WorldWideScience

Sample records for planetary radiative balance

  1. Energy Balance Models and Planetary Dynamics

    Science.gov (United States)

    Domagal-Goldman, Shawn

    2012-01-01

    We know that planetary dynamics can have a significant affect on the climate of planets. Planetary dynamics dominate the glacial-interglacial periods on Earth, leaving a significant imprint on the geological record. They have also been demonstrated to have a driving influence on the climates of other planets in our solar system. We should therefore expect th.ere to be similar relationships on extrasolar planets. Here we describe a simple energy balance model that can predict the growth and thickness of glaciers, and their feedbacks on climate. We will also describe model changes that we have made to include planetary dynamics effects. This is the model we will use at the start of our collaboration to handle the influence of dynamics on climate.

  2. Radiation protection for human interplanetary spaceflight and planetary surface operations

    Energy Technology Data Exchange (ETDEWEB)

    Clark, B.C. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)]|[DLR Inst. of Aerospace Medicine, Cologne (Germany)]|[NASA, Goddard Space Flight Center, Greenbelt, MD (United States)

    1993-12-31

    Radiation protection issues are reviewed for five categories of radiation exposure during human missions to the moon and Mars: trapped radiation belts, galactic cosmic rays, solar flare particle events, planetary surface emissions, and on-board radiation sources. Relative hazards are dependent upon spacecraft and vehicle configurations, flight trajectories, human susceptibility, shielding effectiveness, monitoring and warning systems, and other factors. Crew cabins, interplanetary mission modules, surface habitats, planetary rovers, and extravehicular mobility units (spacesuits) provide various degrees of protection. Countermeasures that may be taken are reviewed relative to added complexity and risks that they could entail, with suggestions for future research and analysis.

  3. Do planetary seasons play a role in attaining stable climates?

    DEFF Research Database (Denmark)

    Olsen, Kasper Wibeck; Bohr, Jakob

    2018-01-01

    A simple phenomenological account for planetary climate instabilities is presented. The description is based on the standard model where the balance of incoming stellar radiation and outward thermal radiation is described by the effective planet temperature. Often, it is found to have three diffe...

  4. Continental Ice Sheets and the Planetary Radiation Budget

    NARCIS (Netherlands)

    Oerlemans, J.

    1980-01-01

    The interaction between continental ice sheets and the planetary radiation budget is potentially important in climate-sensitivity studies. A simple ice-sheet model incorporated in an energybalance climate model provides a tool for studying this interaction in a quantitative way. Experiments in which

  5. Radiation balances and the solar constant

    Science.gov (United States)

    Crommelynck, D.

    1981-01-01

    The radiometric concepts are defined in order to consider various types of radiation balances and relate them to the diabetic form of the energy balance. Variability in space and time of the components of the radiation field are presented. A specific concept for sweeping which is tailored to the requirements is proposed. Finally, after establishing the truncated character of the present knowledge of the radiation balance. The results of the last observations of the solar constant are given. Ground and satellite measurement techniques are discussed.

  6. Do planetary seasons play a role in attaining stable climates?

    Science.gov (United States)

    Olsen, Kasper Wibeck; Bohr, Jakob

    2018-05-01

    A simple phenomenological account for planetary climate instabilities is presented. The description is based on the standard model where the balance of incoming stellar radiation and outward thermal radiation is described by the effective planet temperature. Often, it is found to have three different points, or temperatures, where the influx of radiation is balanced with the out-flux, even with conserved boundary conditions. Two of these points are relatively long-term stable, namely the point corresponding to a cold climate and the point corresponding to a hot climate. In a classical sense these points are equilibrium balance points. The hypothesis promoted in this paper is the possibility that the intermediate third point can become long-term stable by being driven dynamically. The initially unstable point is made relatively stable over a long period by the presence of seasonal climate variations.

  7. Langmuir-like waves and radiation in planetary foreshocks

    Science.gov (United States)

    Cairns, Iver H.; Robinson, P. A.; Anderson, R. R.; Gurnett, D. A.; Kurth, W. S.

    1995-01-01

    The basic objectives of this NASA Grant are to develop theoretical understandings (tested with spacecraft data) of the generation and characteristics of electron plasma waves, commonly known as Langmuir-like waves, and associated radiation near f(sub p) and 2f(sub p) in planetary foreshocks. (Here f(sub p) is plasma frequency.) Related waves and radiation in the source regions of interplanetary type III solar radio bursts provide a simpler observational and theoretical context for developing and testing such understandings. Accordingly, applications to type III bursts constitute a significant fraction of the research effort. The testing of the new Stochastic Growth Theory (SGT) for type III bursts, and its extension and testing for foreshock waves and radiation, constitutes a major longterm strategic goal of the research effort.

  8. Energy balance in processes of transition radiation

    International Nuclear Information System (INIS)

    Vladimirov, S.V.; Tsytovich, V.N.

    1985-01-01

    The authors consider the transition radiation arising when a charged particle crosses an interface between two nonabsorbing media. It is shown that energy balance is observed under these circumstances. The fulfillment of energy balance in transition radiation for nonabsorbing media is rigorously demonstrated. This allows one to find the energy of the transition radiation from the change in the energy of the intrinsic field of the charge and the work of forces for volume waves, which in a number of cases of complicated configurations may prove to be considerably simpler than a direct calculation of the radiation power. For surface waves, a calculation of the work of forces enables one to determine the radiation power directly

  9. Clouds and the earth's radiation balance

    Energy Technology Data Exchange (ETDEWEB)

    Schmetz, J; Raschke, E

    1986-01-01

    Cloud formation mechanisms and cloud effects must be known for all regions of the earth for two important purposes of weather and climate research: First, the circulation characteristics of the atmosphere can be defined and understood only if the energy transfer between the atmosphere and the earth's surface is known; secondly, the energy transfer calculations should be as realistic as possible. The article discusses the influence of clouds on the radiation balance of the earth/atmosphere radiation balance, and the effects on weather and climate.

  10. Elaboration of collisional–radiative models for flows related to planetary entries into the Earth and Mars atmospheres

    International Nuclear Information System (INIS)

    Bultel, Arnaud; Annaloro, Julien

    2013-01-01

    The most relevant way to predict the excited state number density in a nonequilibrium plasma is to elaborate a collisional–radiative (CR) model taking into account most of the collisional and radiative elementary processes. Three examples of such an elaboration are given in this paper in the case of various plasma flows related to planetary atmospheric entries. The case of theoretical determination of nitrogen atom ionization or recombination global rate coefficients under electron impact is addressed first. The global rate coefficient can be implemented in multidimensional computational fluid dynamics calculations. The case of relaxation after a shock front crossing a gas of N 2 molecules treated in the framework of the Rankine–Hugoniot assumptions is also studied. The vibrational and electronic specific CR model elaborated in this case allows one to understand how the plasma reaches equilibrium and to estimate the role of the radiative losses. These radiative losses play a significant role at low pressure in the third case studied. This case concerns CO 2 plasma jets inductively generated in high enthalpy wind tunnels used as ground test facilities. We focus our attention on the behaviour of CO and C 2 electronic excited states, the radiative signature of which can be particularly significant in this type of plasma. These three cases illustrate the elaboration of CR models and their coupling with balance equations. (paper)

  11. Radiation balance of an alfalfa crop in Saudi Arabia

    International Nuclear Information System (INIS)

    Al-Yemeni, M.N.; Grace, J.

    1995-01-01

    Short-wave reflectivity or albedo is an important component of net radiation which represents the major determinant of radiation balance of crop surface. This study was conducted on an irrigated alfalfa crop field at Al-Kharj agricultural area in Saudi Arabia, grown according to normal agricultural practices. Data on radiation balance and crop cover were collected over a number of days from March to October 1986, crop albedo varying from 0–4 in early morning to 0–20 at noon, the overall mean value of the crop albedo being estimated at 0–26. The relation between the individual components of radiation balance was studied, and a significant correlation between incident radiation and net radiation was found. Possible causes responsible for changes in crop albedo were discussed. (author)

  12. Radiation balance diversity on NW Spitsbergen in 2010–2014

    Directory of Open Access Journals (Sweden)

    Kejna Marek

    2017-03-01

    Full Text Available This article presents the results of observations of selected fluxes of the radiation balance in north-western Spitsbergen in the years from 2010 to 2014. Measurements were taken in Ny-Ålesund and in the area of Kaffiøyra, on different surface types occurring in the Polar zone: moraine, tundra, snow and ice. Substantial differences in the radiation balance among the various types of surface were observed. The observations carried out in the summer seasons of 2010–2014 in the area of Kaffiøyra demonstrated that the considerable reflection of solar radiation on the Waldemar Glacier (albedo 55% resulted in a smaller solar energy net income. During the polar day, a diurnal course of the components of the radiation balance was apparently related to the solar elevation angle. When the sun was low over the horizon, the radiation balance became negative, especially on the glacier. Diurnal, annual and multi-annual variations in the radiation balance have a significant influence on the functioning of the environment in polar conditions.

  13. Radiative Transfer Modeling in Proto-planetary Disks

    Science.gov (United States)

    Kasper, David; Jang-Condell, Hannah; Kloster, Dylan

    2016-01-01

    Young Stellar Objects (YSOs) are rich astronomical research environments. Planets form in circumstellar disks of gas and dust around YSOs. With ever increasing capabilities of the observational instruments designed to look at these proto-planetary disks, most notably GPI, SPHERE, and ALMA, more accurate interfaces must be made to connect modeling of the disks with observation. PaRTY (Parallel Radiative Transfer in YSOs) is a code developed previously to model the observable density and temperature structure of such a disk by self-consistently calculating the structure of the disk based on radiative transfer physics. We present upgrades we are implementing to the PaRTY code to improve its accuracy and flexibility. These upgrades include: creating a two-sided disk model, implementing a spherical coordinate system, and implementing wavelength-dependent opacities. These upgrades will address problems in the PaRTY code of infinite optical thickness, calculation under/over-resolution, and wavelength-independent photon penetration depths, respectively. The upgraded code will be used to better model disk perturbations resulting from planet formation.

  14. Clouds-radiation interactions in a general circulation model - Impact upon the planetary radiation balance

    Science.gov (United States)

    Smith, Laura D.; Vonder Haar, Thomas H.

    1991-01-01

    Simultaneously conducted observations of the earth radiation budget and the cloud amount estimates, taken during the June 1979 - May 1980 Nimbus 7 mission were used to show interactions between the cloud amount and raidation and to verify a long-term climate simulation obtained with the latest version of the NCAR Community Climate Model (CCM). The parameterization of the radiative, dynamic, and thermodynamic processes produced the mean radiation and cloud quantities that were in reasonable agreement with satellite observations, but at the expense of simulating their short-term fluctuations. The results support the assumption that the inclusion of the cloud liquid water (ice) variable would be the best mean to reduce the blinking of clouds in NCAR CCM.

  15. Solar radiation, cloudiness and longwave radiation over low-latitude glaciers: implications for mass-balance modelling

    Science.gov (United States)

    Mölg, Thomas; Cullen, Nicolas J.; Kaser, Georg

    Broadband radiation schemes (parameterizations) are commonly used tools in glacier mass-balance modelling, but their performance at high altitude in the tropics has not been evaluated in detail. Here we take advantage of a high-quality 2 year record of global radiation (G) and incoming longwave radiation (L↓) measured on Kersten Glacier, Kilimanjaro, East Africa, at 5873 m a.s.l., to optimize parameterizations of G and L↓. We show that the two radiation terms can be related by an effective cloud-cover fraction neff, so G or L↓ can be modelled based on neff derived from measured L↓ or G, respectively. At neff = 1, G is reduced to 35% of clear-sky G, and L↓ increases by 45-65% (depending on altitude) relative to clear-sky L↓. Validation for a 1 year dataset of G and L↓ obtained at 4850 m on Glaciar Artesonraju, Peruvian Andes, yields a satisfactory performance of the radiation scheme. Whether this performance is acceptable for mass-balance studies of tropical glaciers is explored by applying the data from Glaciar Artesonraju to a physically based mass-balance model, which requires, among others, G and L↓ as forcing variables. Uncertainties in modelled mass balance introduced by the radiation parameterizations do not exceed those that can be caused by errors in the radiation measurements. Hence, this paper provides a tool for inclusion in spatially distributed mass-balance modelling of tropical glaciers and/or extension of radiation data when only G or L↓ is measured.

  16. AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES

    International Nuclear Information System (INIS)

    Robinson, Tyler D.; Catling, David C.

    2012-01-01

    We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

  17. Radiation beamline testbeds for the simulation of planetary and spacecraft environments for human and robotic mission risk assessment

    Science.gov (United States)

    Wilkins, Richard

    The Center for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View A&M University, Prairie View, Texas, USA, is establishing an integrated, multi-disciplinary research program on the scientific and engineering challenges faced by NASA and the inter-national space community caused by space radiation. CRESSE focuses on space radiation research directly applicable to astronaut health and safety during future long term, deep space missions, including Martian, lunar, and other planetary body missions beyond low earth orbit. The research approach will consist of experimental and theoretical radiation modeling studies utilizing particle accelerator facilities including: 1. NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory; 2. Proton Synchrotron at Loma Linda University Med-ical Center; and 3. Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory. Specifically, CRESSE investigators are designing, developing, and building experimental test beds that simulate the lunar and Martian radiation environments for experiments focused on risk assessment for astronauts and instrumentation. The testbeds have been designated the Bioastronautics Experimental Research Testbeds for Environmental Radiation Nostrum Investigations and Education (BERT and ERNIE). The designs of BERT and ERNIE will allow for a high degree of flexibility and adaptability to modify experimental configurations to simulate planetary surface environments, planetary habitats, and spacecraft interiors. In the nominal configuration, BERT and ERIE will consist of a set of experimental zones that will simulate the planetary atmosphere (Solid CO2 in the case of the Martian surface.), the planetary surface, and sub-surface regions. These experimental zones can be used for dosimetry, shielding, biological, and electronic effects radiation studies in support of space exploration missions. BERT and ERNIE are designed to be compatible with the

  18. Infrared studies of galactic nebulae. IV - Continuum and line radiation from planetary nebulae.

    Science.gov (United States)

    Gillett, F. C.; Merrill, K. M.; Stein, W. A.

    1972-01-01

    Observations are reported of the detection of IR radiation from several planetary nebulae not previously known to be radiating at these wavelengths. Broad spectral bandwidth observations indicate that ir radiation in excess of that expected from atomic processes is a common phenomenon among these objects. Investigations with narrow spectral bandwidth show that in a few cases the energy in the 10.52-micron line is a significant fraction of the total energy observed in the broad-band measurements and in other cases a relatively small fraction of the total radiation. Other observations on two sources with narrow spectral bandwidth adjacent to the 10.52-micron line indicate that at these wavelengths a true continuum of radiation exists as well as lines. The results are discussed in relation to visual and radio-wavelength data.

  19. Energy-balance climate models: stability experiments with a refined albedo and updated coefficients for infrared emission

    NARCIS (Netherlands)

    Oerlemans, J.

    1978-01-01

    A zonally averaged' climate model of the energy-balance type is examined. Recently published satellite measurements were used to improve existing parameterizations of planetary albedo and outgoing radiation in terms of surface and sea level temperature. A realistic constant for the diffusion of

  20. Radiation and energy balance of lettuce culture inside a polyethylene greenhouse

    International Nuclear Information System (INIS)

    Frisina, V. de A.; Escobedo, J.F.

    1999-01-01

    The objective of this paper was to describe the radiation and energy balance, during the lettuce (Lactuca sativa, L. cv. Verônica) crop cycle inside a polyethylene greenhouse. The radiation and energy balance was made inside a tunnel greenhouse with polyethylene cover (100 mm) and in an external area, both areas with 35 m 2 . Global, reflected and net radiation, soil heat flux and air temperature (dry and humid) were measured during the crop cycle. A Datalogger, which operated at 1 Hz frequency, storing 5 minutes averages was utilized. The global (K↓) and reflected (K) radiations showed that the average transmission of global radiation (K↓in / K↓ex) was almost constant, near to 79.59%, while the average ratio of reflected radiation (Kin / Kex) was 69.21% with 8.47% standard-deviation. The normalized curves of short-wave net radiation, in relation to the global radiation (K*/ K↓), found for both environments, were almost constant at the beginning of cycle; this relation decreased in the final stage of culture. The normalized relation (Rn/ K↓) was bigger in the external area, about 12%, when the green culture covered the soil surface. The long-wave radiation balance average (L*) was bigger outside, about 50%. The energy balance, estimated in terms of vertical fluxes, showed that, for the external area, in average, 83.07% of total net radiation was converted in latent heat evaporation (LE), and 18% in soil heat flux (G), and 9.96% in sensible heat (H), while inside of the greenhouse, 58.71% of total net radiation was converted in LE, 42.68% in H, and 28.79% in G. (author) [pt

  1. Influence of soybean pubescence type on radiation balance

    International Nuclear Information System (INIS)

    Nielsen, D.C.; Blad, B.I.; Verma, S.B.; Rosenberg, N.J.; Specht, J.E.

    1984-01-01

    Increasing the density of pubescence on the leaves and stems of soybeans (Glycine max L.) should influence the radiation balance of the soybean canopy and affect the evapotranspiration and photosynthetic rates. This study was undertaken to evaluate the influence of increased pubescence density on various components of the radiation balance. Near-isogenic lines of two soybean cultivars (Clark and Harosoy) were grown in four adjacent small plots (18 m · 18 m) during the 1980, 1981, and 1982 growing seasons near Mead, Nebr. The soil at this site is classified as a Typic Argiudoll. The isolines of each cultivar varied only in the amount of pubescence (dense vs. normal pubescence). Measurements of albedo, reflected photosynthetically active radiation (PAR), emitted longwave radiation, and net radiation were made over the crop surfaces with instruments mounted on a rotating boom located at the intersection of the four plots. Radiative canopy temperatures were measured with a handheld infrared thermometer (IRT). Results show that dense pubescence increased reflection of shortwave radiation and PAR by 3 to 5% and 8 to 11%, respectively. Emitted longwave radiation and radiative canopy temperature were not significantly affected by increased pubescence, although there was a slight tendency for the dense pubescent canopy to be cooler. Increased pubescence decreased net radiation over the canopy by 0.5 to 1.5%. These results suggest that soybeans with dense pubescence may be slightly better adapted to the high radiation, high temperature, and limited moisture conditions of the eastern Great Plains than are those with normal pubescence

  2. Infrared radiation in the energy balance of the upper atmosphere

    International Nuclear Information System (INIS)

    Gordiets, B.F.; Markov, M.N.

    1977-01-01

    The contribution of the infrared radiation to the energy balance of the Earth's upper atmosphere is discussed. The theoretical analysis has been carried out of the mechanisms of the transformation of the energy of outgoing particles and the ultraviolet-radiation of the Sun absorbed at the heights of Z >= 90 km into the infrared radiation. It is found out the the infrared radiation within the wave length range of 1.2-20 μ is more intensive that the 63 μ radiation of atomic oxygen and plays an important role in the general energy balance and the thermal regime of the thermosphere. It has been found out too that in the area of Z >= 120 km heights the radiation in the 5.3 μ NO band is the most intensive. This radiation is to be considered for the more accurate description of parameters of the atmosphere (temperature, density) conditioning the nature of the translocation of ionospheric sounds (ISS)

  3. PBMC: Pre-conditioned Backward Monte Carlo code for radiative transport in planetary atmospheres

    Science.gov (United States)

    García Muñoz, A.; Mills, F. P.

    2017-08-01

    PBMC (Pre-Conditioned Backward Monte Carlo) solves the vector Radiative Transport Equation (vRTE) and can be applied to planetary atmospheres irradiated from above. The code builds the solution by simulating the photon trajectories from the detector towards the radiation source, i.e. in the reverse order of the actual photon displacements. In accounting for the polarization in the sampling of photon propagation directions and pre-conditioning the scattering matrix with information from the scattering matrices of prior (in the BMC integration order) photon collisions, PBMC avoids the unstable and biased solutions of classical BMC algorithms for conservative, optically-thick, strongly-polarizing media such as Rayleigh atmospheres.

  4. Aerosol influence on energy balance of the middle atmosphere of Jupiter.

    Science.gov (United States)

    Zhang, Xi; West, Robert A; Irwin, Patrick G J; Nixon, Conor A; Yung, Yuk L

    2015-12-22

    Aerosols are ubiquitous in planetary atmospheres in the Solar System. However, radiative forcing on Jupiter has traditionally been attributed to solar heating and infrared cooling of gaseous constituents only, while the significance of aerosol radiative effects has been a long-standing controversy. Here we show, based on observations from the NASA spacecraft Voyager and Cassini, that gases alone cannot maintain the global energy balance in the middle atmosphere of Jupiter. Instead, a thick aerosol layer consisting of fluffy, fractal aggregate particles produced by photochemistry and auroral chemistry dominates the stratospheric radiative heating at middle and high latitudes, exceeding the local gas heating rate by a factor of 5-10. On a global average, aerosol heating is comparable to the gas contribution and aerosol cooling is more important than previously thought. We argue that fractal aggregate particles may also have a significant role in controlling the atmospheric radiative energy balance on other planets, as on Jupiter.

  5. Ultraviolet radiation from F and K stars and implications for planetary habitability

    Science.gov (United States)

    Kasting, J. F.; Whittet, D. C.; Sheldon, W. R.

    1997-01-01

    Now that extrasolar planets have been found, it is timely to ask whether some of them might be suitable for life. Climatic constraints on planetary habitability indicate that a reasonably wide habitable zone exists around main sequence stars with spectral types in the early-F to mid-K range. However, it has not been demonstrated that planets orbiting such stars would be habitable when biologically-damaging energetic radiation is also considered. The large amounts of UV radiation emitted by early-type stars have been suggested to pose a problem for evolving life in their vicinity. But one might also argue that the real problem lies with late-type stars, which emit proportionally less radiation at the short wavelengths (lambda < 200 nm) required to split O2 and initiate ozone formation. We show here that neither of these concerns is necessarily fatal to the evolution of advanced life: Earth-like planets orbiting F and K stars may well receive less harmful UV radiation at their surfaces than does the Earth itself.

  6. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1980-01-01

    A two-component dust model is suggested to explain the infrared emission from planetary nebulae. A cold dust component located in the extensive remnant of the red-giant envelope exterior to the visible nebula is responsible for the far-infrared emission. A ward dust component, which is condensed after the formation of the planetary nebula and confined within the ionized gas shell, emits most of the near- and mid-infrared radiation. The observations of NGC 7027 are shown to be consisten with such a model. The correlation of silicate emission in several planetary nebulae with an approximately +1 spectral index at low radio frequencies suggests that both the silicate and radio emissions originate from the remnant of the circumstellar envelope of th precursor star and are observable only while the planetary nebula is young. It is argued that oxygen-rich stars as well as carbon-rich stars can be progenitors of planetary nebulae

  7. ARTS, the Atmospheric Radiative Transfer Simulator - version 2.2, the planetary toolbox edition

    Science.gov (United States)

    Buehler, Stefan A.; Mendrok, Jana; Eriksson, Patrick; Perrin, Agnès; Larsson, Richard; Lemke, Oliver

    2018-04-01

    This article describes the latest stable release (version 2.2) of the Atmospheric Radiative Transfer Simulator (ARTS), a public domain software for radiative transfer simulations in the thermal spectral range (microwave to infrared). The main feature of this release is a planetary toolbox that allows simulations for the planets Venus, Mars, and Jupiter, in addition to Earth. This required considerable model adaptations, most notably in the area of gaseous absorption calculations. Other new features are also described, notably radio link budgets (including the effect of Faraday rotation that changes the polarization state) and the treatment of Zeeman splitting for oxygen spectral lines. The latter is relevant, for example, for the various operational microwave satellite temperature sensors of the Advanced Microwave Sounding Unit (AMSU) family.

  8. Integrating polarized light over a planetary disk applied to starlight reflected by extrasolar planets

    NARCIS (Netherlands)

    Stam, D.M.; de Rooij, W.A.; Cornet, G.; Hovenier, J.W.

    2006-01-01

    We present an efficient numerical method for integrating planetary radiation over a planetary disk, which is especially interesting for simulating signals of extrasolar planets. Our integration method is applicable to calculating the full flux vector of the disk-integrated planetary radiation, i.e.

  9. A simple method to compute the change in earth-atmosphere radiative balance due to a stratospheric aerosol layer

    Science.gov (United States)

    Lenoble, J.; Tanre, D.; Deschamps, P. Y.; Herman, M.

    1982-01-01

    A computer code was developed in terms of a three-layer model for the earth-atmosphere system, using a two-stream approximation for the troposphere and stratosphere. The analysis was limited to variable atmosphere loading by solar radiation over an unperturbed section of the atmosphere. The scattering atmosphere above a Lambertian ground layer was considered in order to derive the planar albedo and the spherical albedo. Attention was given to the influence of the aerosol optical thickness in the stratosphere, the single scattering albedo and asymmetry factor, and the sublayer albedo. Calculations were performed of the zonal albedo and the planetary radiation balance, taking into account a stratospheric aerosol layer containing H2SO4 droplets and volcanic ash. The resulting ground temperature disturbance was computed using a Budyko (1969) climate model. Local decreases in the albedo in the summer were observed in high latitudes, implying a heating effect of the aerosol. An accompanying energy loss of 23-27 W/sq m was projected, which translates to surface temperature decreases of either 1.1 and 0.45 C, respectively, for background and volcanic aerosols.

  10. Analysis of the temporal variation of radiation balance components in arid rice (Oryza sativa L.) culture

    International Nuclear Information System (INIS)

    Prates, J.E.; Coelho, D.T.; Steinmetz, S.

    1988-01-01

    The time variation of measured radiation balance components in a cultived rice area (Oryza sativa L.) under arid conditions in the Brazil central-west region was analysed. The relation between global solar radiation, radiation balance, reflected radiation and terrestrial effective radiation in three different stages of the culture development: vegetative stage; blooming and maturation, was determined. (M.C.K.) [pt

  11. Measuring and interpreting X-ray fluorescence from planetary surfaces.

    Science.gov (United States)

    Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

    2008-11-15

    As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

  12. Energy Balance Models of planetary climate as a tool for investigating the habitability of terrestrial planets and its evolution

    Science.gov (United States)

    Ferri, G.; Murante, G.; Provenzale, A.; Silva, L.; Vladilo, G.

    2012-04-01

    The study of the habitability and potential for life formation of terrestrial planets requires a considerable work of modelization owing to the limited amount of experimental constraints typical of this type of research. As an example, the paucity of experimental Archean data severely limits the study of the habitability of the primitive Earth at the epoch of the origin of life. In the case of exoplanets the amount of experimental information available is quite limited and the need for modelization strong. Here we focus on the modelization of the surface planetary temperature, a key thermodynamical quantity used to define the habitability. Energy Balance Models (EBM) of planetary climate provide a simple way to calculate the temperature-latitude profile of terrestrial planets with a small amount of computing resources. Thanks to this fact EBMs offer an excellent tool to exploring a wide range of parameter space and therefore testing the effects of variations of physical/chemical quantities unconstrained by experimental data. In particular, one can easily probe possible scenarios of habitability at different stages of planetary evolution. We have recently implemented one-dimensional EBMs featuring the possibility of probing variations of astronomical and geophysical parameters, such as stellar luminosity, orbital semi-major axis and eccentricity, obliquity of the planetary axis, planet rotational velocity, land/ocean surface fractions and thermal capacities, and latitudinal heat diffusion. After testing our models against results obtained in previous work (Williams & Kasting 1997, Icarus, 129, 254; Spiegel et al. 2008, ApJ, 681, 1609), we introduced a novel parametrization of the diffusion coefficient as a function of the stellar zenith distance. Our models have been validated using the mean temperature-latitude profiles of the present Earth and its seasonal variations; the global albedo has been used as an additional constraint. In this work we present specific

  13. Radiation balance in a deep Colorado valley: ASCOT 84

    International Nuclear Information System (INIS)

    Whiteman, C.D.; Fritschen, L.J.; Simpson, J.R.; Orgill, M.M.

    1984-12-01

    Five surface energy budget stations were installed at four sites in a deep, narrow valley in western Colorado as part of the Atmospheric Studies in Complex Terrain (ASCOT) Study. Radiation balance data are presented from these stations for the clear day September 29, 1984. 3 references, 3 figures, 3 tables

  14. X-ray observations of planetary nebulae

    International Nuclear Information System (INIS)

    Apparao, K.M.V.; Tarafdar, S.P.

    1990-01-01

    The Einstein satellite was used to observe 19 planetary nebulae and X-ray emission was detected from four planetary nebulae. The EXOSAT satellite observed 12 planetary nebulae and five new sources were detected. An Einstein HRI observation shows that NGC 246 is a point source, implying that the X-rays are from the central star. Most of the detected planetary nebulae are old and the X-rays are observed during the later stage of planetary nebulae/central star evolution, when the nebula has dispersed sufficiently and/or when the central star gets old and the heavy elements in the atmosphere settle down due to gravitation. However in two cases where the central star is sufficiently luminous X-rays were observed, even though they were young nebulae; the X-radiation ionizes the nebula to a degree, to allow negligible absorption in the nebula. Temperature T x is obtained using X-ray flux and optical magnitude and assuming the spectrum is blackbody. T x agrees with Zanstra temperature obtained from optical Helium lines. (author)

  15. Explicit validation of a surface shortwave radiation balance model over snow-covered complex terrain

    Science.gov (United States)

    Helbig, N.; Löwe, H.; Mayer, B.; Lehning, M.

    2010-09-01

    A model that computes the surface radiation balance for all sky conditions in complex terrain is presented. The spatial distribution of direct and diffuse sky radiation is determined from observations of incident global radiation, air temperature, and relative humidity at a single measurement location. Incident radiation under cloudless sky is spatially derived from a parameterization of the atmospheric transmittance. Direct and diffuse sky radiation for all sky conditions are obtained by decomposing the measured global radiation value. Spatial incident radiation values under all atmospheric conditions are computed by adjusting the spatial radiation values obtained from the parametric model with the radiation components obtained from the decomposition model at the measurement site. Topographic influences such as shading are accounted for. The radiosity approach is used to compute anisotropic terrain reflected radiation. Validations of the shortwave radiation balance model are presented in detail for a day with cloudless sky. For a day with overcast sky a first validation is presented. Validation of a section of the horizon line as well as of individual radiation components is performed with high-quality measurements. A new measurement setup was designed to determine terrain reflected radiation. There is good agreement between the measurements and the modeled terrain reflected radiation values as well as with incident radiation values. A comparison of the model with a fully three-dimensional radiative transfer Monte Carlo model is presented. That validation reveals a good agreement between modeled radiation values.

  16. The energy balance experiment EBEX-2000. Part III: Behaviour and quality of the radiation measurements

    NARCIS (Netherlands)

    Kohsiek, W.; Liebethal, C.; Foken, T.; Vogt, R.; Oncley, S.P.; Bernhofer, C.; Debruin, H.A.R.

    2007-01-01

    An important part of the Energy Balance Experiment (EBEX-2000) was the measurement of the net radiation and its components. Since the terrain, an irrigated cotton field, could not be considered homogeneous, radiation measurements were made at nine sites using a variety of radiation instruments,

  17. Small reactor power systems for manned planetary surface bases

    Energy Technology Data Exchange (ETDEWEB)

    Bloomfield, H.S.

    1987-12-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

  18. Small reactor power systems for manned planetary surface bases

    International Nuclear Information System (INIS)

    Bloomfield, H.S.

    1987-12-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options

  19. A modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    , but not for balanced antennas like loops or dipoles. In this paper, a modified Wheeler cap method is proposed for the radiation efficiency measurement of balanced electrically small antennas and a three-port network model of the Wheeler cap measurement is introduced. The advantage of the modified method...... is that it is wideband, thus does not require any balun, and both the antenna input impedance and radiation efficiency can be obtained. An electrically small loop antenna and a wideband dipole were simulated and measured according to the proposed method and the results of measurements and simulations are presented...

  20. Population-based mammography screening below age 50: Balancing radiation-induced vs prevented breast cancer deaths

    NARCIS (Netherlands)

    R. de Gelder (Rianne); G. Draisma (Gerrit); E.A.M. Heijnsdijk (Eveline); H.J. de Koning (Harry)

    2011-01-01

    textabstractIntroduction:Exposure to ionizing radiation at mammography screening may cause breast cancer. Because the radiation risk increases with lower exposure age, advancing the lower age limit may affect the balance between screening benefits and risks. The present study explores the

  1. Partitioning of radiation and energy balance components in an inhomogeneous desert valley

    International Nuclear Information System (INIS)

    Malek, E.; Bingham, G.E.

    1997-01-01

    Radiation and energy balance components are required to validate global, regional, and local scale models representing surface heat flux relationships in the heterogeneous surfaces of the world's arid and desert regions. Research was conducted in north-eastern Nevada, U.S.A., in a Great Basin inhomogeneous semi-arid desert valley located at 40° 44′ N, 114° 26′ W, with an elevation of 1707 m above mean sea level, to study the daily, monthly, and annual mesoscale radiation and energy balance components. We established five radiation stations along with five Bowen ratio systems to measure the incoming (R si ) and outgoing (R so ) solar (shortwave) radiation, net (R n ) radiation, air temperatures and moisture at 1 and 2 m above-ground, the aggregated (soil + vegetation) surface temperature, soil heat flux at 8 cm (three locations at each station), soil temperatures at 2 and 6 cm above each soil flux plate, wind speed and direction at 10 m, and precipitation (if any) every 5 s averaged into 20 min throughout the valley during the 93–94 water year (beginning 1 October). Our study during the 93–94 water year showed that albedo (R so /R si ) ranged from 85% (snow-covered surface) to 10% (cloudy skies with wet surface) among stations. The water year total incoming solar radiation (averaged among stations) amounted to 6·33 × 10 3 MJ·m −2 and about 24% of that was reflected back to the atmosphere. The net longwave radiation (R ln = R lo − R li ) was about 32% of R si , where R lo and R li are the terrestrial (outgoing) and atmospheric (incoming) longwave radiation, respectively. The 93–94 water year average net radiation (R n ) among stations amounted to 2·68 × 10 3 MJ·m −2 (about 44% of R si ). Approximately 85·3% and 14·6% of R n were used for the processes of sensible (H) and latent (LE) heat fluxes, respectively. The annual R n contribution to surface soil heat flux (G surf ) was almost 0·1%. Monthly and annual relationships among

  2. Radiation losses and global power balance of JT-60 plasmas

    International Nuclear Information System (INIS)

    Nishitani, T.; Itami, K.; Nagashima, K.; Tsuji, S.; Hosogane, N.; Yoshida, H.; Ando, T.; Kubo, H.; Takeuchi, H.

    1990-01-01

    The radiation losses and the global power balance for Ohmic and neutral beam heated plasmas have been investigated in different JT-60 configurations. Discharges with a TiC coated molybdenum wall and with a graphite wall, with limiter, outer and lower X-point configurations have been studied by bolometric measurements, thermocouples and an infrared TV camera. In neutral beam heated outer X-point discharges with a TiC coated molybdenum first wall, the radiation loss of the main plasma was very low (10% of the absorbed power). The radiation loss due to oxygen was dominant in this case. On the contrary, in discharges with TiC coated molybdenum limiters the radiation loss was very high (>60% of the absorbed power). In the discharges with a graphite wall the radiated power from the main plasma was 20-25% for both limiter and lower X-point configurations. In lower X-point discharges the main contributor to the radiation loss was oxygen, whereas in limiter discharges the loss due to carbon was equal to the loss due to oxygen. The radiation loss from the lower X-point divertor increased with increasing electron density of the main plasma. (author). 33 refs, 14 figs, 1 tab

  3. Photochemistry of Planetary Atmospheres

    Science.gov (United States)

    Yung, Y. L.

    2005-12-01

    The Space Age started half a century ago. Today, with the completion of a fairly detailed study of the planets of the Solar System, we have begun studying exoplanets (or extrasolar planets). The overriding question in is to ask whether an exoplanet is habitable and harbors life, and if so, what the biosignatures ought to be. This forces us to confront the fundamental question of what controls the composition of an atmosphere. The composition of a planetary atmosphere reflects a balance between thermodynamic equilibrium chemistry (as in the interior of giant planets) and photochemistry (as in the atmosphere of Mars). The terrestrial atmosphere has additional influence from life (biochemistry). The bulk of photochemistry in planetary atmospheres is driven by UV radiation. Photosynthesis may be considered an extension of photochemistry by inventing a molecule (chlorophyll) that can harvest visible light. Perhaps the most remarkable feature of photochemistry is catalytic chemistry, the ability of trace amounts of gases to profoundly affect the composition of the atmosphere. Notable examples include HOx (H, OH and HO2) chemistry on Mars and chlorine chemistry on Earth and Venus. Another remarkable feature of photochemistry is organic synthesis in the outer solar system. The best example is the atmosphere of Titan. Photolysis of methane results in the synthesis of more complex hydrocarbons. The hydrocarbon chemistry inevitably leads to the formation of high molecular weight products, giving rise to aerosols when the ambient atmosphere is cool enough for them to condense. These results are supported by the findings of the recent Cassini mission. Lastly, photochemistry leaves a distinctive isotopic signature that can be used to trace back the evolutionary history of the atmosphere. Examples include nitrogen isotopes on Mars and sulfur isotopes on Earth. Returning to the question of biosignatures on an exoplanet, our Solar System experience tells us to look for speciation

  4. Planetary interchange of bioactive material: probability factors and implications.

    Science.gov (United States)

    Clark, B C

    2001-01-01

    It is now well-accepted that both lunar and martian materials are represented in the meteorite collections. Early suggestions that viable organisms might survive natural transport between planets have not yet been thoroughly examined. The concept of Planetary Interchange of Bioactive Material (PIBM) is potentially relevant to the conditions under which life originated. PIBM has been also invoked to infer that the potential danger to Earth from martian materials is non-existent, an inference with, however, many pitfalls. Numerous impediments to efficient transfer of viable organisms exist. In this work, the lethality of space radiation during long transients and the biasing of launched objects toward materials unlikely to host abundant organisms are examined and shown to reduce the likelihood of successful transfer by orders of magnitude. It is also shown that martian meteorites studied to date assuredly have been subjected to sterilizing levels of ionizing radiation in space. PIBM considerations apply to both the solar system locale(s) of the origin of life and to the applicability of planetary protection protocols to preserve the biospheres of planetary bodies, including our own.

  5. Impact of cloud microphysics on cloud-radiation interactions in the CSU general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, L.D.; Randall, D.A.

    1995-04-01

    Our ability to study and quantify the impact of cloud-radiation interactions in studying global scale climate variations strongly relies upon the ability of general circulation models (GCMs) to simulate the coupling between the spatial and temporal variations of the model-generated cloudiness and atmospheric moisture budget components. In particular, the ability of GCMs to reproduce the geographical distribution of the sources and sinks of the planetary radiation balance depends upon their representation of the formation and dissipation of cloudiness in conjunction with cloud microphysics processes, and the fractional amount and optical characteristics of cloudiness in conjunction with the mass of condensate stored in the atmosphere. A cloud microphysics package which encompasses five prognostic variables for the mass of water vapor, cloud water, cloud ice, rain, and snow has been implemented in the Colorado State University General Circulation Model (CSU GCM) to simulate large-scale condensation processes. Convection interacts with the large-scale environment through the detrainment of cloud water and cloud ice at the top of cumulus towers. The cloud infrared emissivity and cloud optical depth of the model-generated cloudiness are interactive and depend upon the mass of cloud water and cloud ice suspended in the atmosphere. The global atmospheric moisture budget and planetary radiation budget of the CSU GCM obtained from a perpetual January simulation are discussed. Geographical distributions of the atmospheric moisture species are presented. Global maps of the top-of-atmosphere outgoing longwave radiation and planetary albedo are compared against Earth Radiation Budget Experiment (ERBE) satellite data.

  6. Balancing accuracy, efficiency, and flexibility in a radiative transfer parameterization for dynamical models

    Science.gov (United States)

    Pincus, R.; Mlawer, E. J.

    2017-12-01

    Radiation is key process in numerical models of the atmosphere. The problem is well-understood and the parameterization of radiation has seen relatively few conceptual advances in the past 15 years. It is nonthelss often the single most expensive component of all physical parameterizations despite being computed less frequently than other terms. This combination of cost and maturity suggests value in a single radiation parameterization that could be shared across models; devoting effort to a single parameterization might allow for fine tuning for efficiency. The challenge lies in the coupling of this parameterization to many disparate representations of clouds and aerosols. This talk will describe RRTMGP, a new radiation parameterization that seeks to balance efficiency and flexibility. This balance is struck by isolating computational tasks in "kernels" that expose as much fine-grained parallelism as possible. These have simple interfaces and are interoperable across programming languages so that they might be repalced by alternative implementations in domain-specific langauges. Coupling to the host model makes use of object-oriented features of Fortran 2003, minimizing branching within the kernels and the amount of data that must be transferred. We will show accuracy and efficiency results for a globally-representative set of atmospheric profiles using a relatively high-resolution spectral discretization.

  7. EDITORIAL: The Earth radiation balance as driver of the global hydrological cycle

    Science.gov (United States)

    Wild, Martin; Liepert, Beate

    2010-06-01

    Variations in the intensity of the global hydrological cycle can have far-reaching effects on living conditions on our planet. While climate change discussions often revolve around possible consequences of future temperature changes, the adaptation to changes in the hydrological cycle may pose a bigger challenge to societies and ecosystems. Floods and droughts are already today amongst the most damaging natural hazards, with floods being globally the most significant disaster type in terms of loss of human life (Jonkman 2005). From an economic perspective, changes in the hydrological cycle can impose great pressures and damages on a variety of industrial sectors, such as water management, urban planning, agricultural production and tourism. Despite their obvious environmental and societal importance, our understanding of the causes and magnitude of the variations of the hydrological cycle is still unsatisfactory (e.g., Ramanathan et al 2001, Ohmura and Wild 2002, Allen and Ingram 2002, Allan 2007, Wild et al 2008, Liepert and Previdi 2009). The link between radiation balance and hydrological cycle Globally, precipitation can be approximated by surface evaporation, since the variability of the atmospheric moisture storage is negligible. This is the case because the fluxes are an order of magnitude larger than the atmospheric storage (423 x 1012 m3 year-1 versus 13 x 1012 m3 according to Baumgartner and Reichel (1975)), the latter being determined by temperature (Clausius-Clapeyron). Hence the residence time of evaporated water in the atmosphere is not more than a few days, before it condenses and falls back to Earth in the form of precipitation. Any change in the globally averaged surface evaporation therefore implies an equivalent change in precipitation, and thus in the intensity of the global hydrological cycle. The process of evaporation requires energy, which it obtains from the surface radiation balance (also known as surface net radiation), composed of the

  8. Seasonal changes in the radiation balance of subarctic forest and tundra

    International Nuclear Information System (INIS)

    Lafleur, P.M.; Renzetti, A.V.; Bello, R.

    1993-01-01

    This paper examines the seasonal behavior of the components of the radiation budget of subarctic tundra and open forest near Churchill, Manitoba. Data were collected between late February and August 1990. The presence of the winter snowpack is the most important factor which affects the difference in radiation balances of tundra and forest. Overall, net radiation was about four to five times larger over the forest when snow covered the ground. Albedo differences were primarily responsible for this difference in net radiation; however, somewhat smaller net longwave losses were experienced at the tundra site. The step decrease in albedo from winter to summer (i.e. snow-covered to snow-free conditions) was significant at both sites. The forest albedo decreased by about three-fold while the tundra experienced a seven-fold decrease. Net radiation at both sites increased in direct response to the albedo change. Transmissivity of the atmosphere near Churchill also appeared to change at about the same time as the loss of the snow cover and may be related to changing air masses which bring about the final snow melt

  9. Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

    Institute of Scientific and Technical Information of China (English)

    W. Kolby SMITH; Wei GAO; Heidi STELTZER

    2009-01-01

    One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth's surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

  10. The effect of carbon monoxide on planetary haze formation

    Energy Technology Data Exchange (ETDEWEB)

    Hörst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2014-01-20

    Organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface. Numerous experiments have investigated the aerosols produced by exposing mixtures of N{sub 2}/CH{sub 4} to a variety of energy sources. However, many N{sub 2}/CH{sub 4} atmospheres in both our solar system and extrasolar planetary systems also contain carbon monoxide (CO). We have conducted a series of atmosphere simulation experiments to investigate the effect of CO on the formation and particle size of planetary haze analogues for a range of CO mixing ratios using two different energy sources, spark discharge and UV. We find that CO strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that CO may play an important, previously unexplored, role in aerosol chemistry in planetary atmospheres.

  11. Ultrasound power measurements of HITU transducer with a more stable radiation force balance

    International Nuclear Information System (INIS)

    Karaboece, B; Sadiko'lu, E; Bilgic, E

    2011-01-01

    A new radiation force balance (RFB) system was established at Turkish National Metrology Institute (UME) Ultrasonics Laboratory for High intensity therapeutic ultrasound (HITU) power measurements. The new system is highly stable at high power levels up to 500 Watts. The measurement system consists of a Plexiglas cylindrical balance arm, target mounting scale disks, conical reflecting and absorbing targets, adjustment nuts, and a hanging wire. Both of the two sides of balance were mounted similar size and weight targets. The equilibrium of the balance arm can be adjusted with nuts on screws located at both sides of the balance arm. Transducer was mounted to bottom of water tank. Absorbers in the bottom and the near walls of the tank were used for reflecting target case. Ultrasound power was applied to one scale of the balance where the reflecting/absorbing target was mounted and corresponding force was measured on the other scale of balance where was connected to a balance with a thin wire while the thin rest standing on a support. Ultrasound power of two HITU transducers at frequencies 0.93 MHz, 1.1 MHz and 3.3 MHz were measured with conventional and new system, the values were compared and uncertainty components were assessed in this paper.

  12. Ultrasound power measurements of HITU transducer with a more stable radiation force balance

    Energy Technology Data Exchange (ETDEWEB)

    Karaboece, B; Sadiko' lu, E; Bilgic, E, E-mail: baki.karaboce@ume.tubitak.gov.t [Tuebitak Ulusal Metroloji Enstituesue (UME), P.K. 54 41470 Gebze-Kocaeli (Turkey)

    2011-02-01

    A new radiation force balance (RFB) system was established at Turkish National Metrology Institute (UME) Ultrasonics Laboratory for High intensity therapeutic ultrasound (HITU) power measurements. The new system is highly stable at high power levels up to 500 Watts. The measurement system consists of a Plexiglas cylindrical balance arm, target mounting scale disks, conical reflecting and absorbing targets, adjustment nuts, and a hanging wire. Both of the two sides of balance were mounted similar size and weight targets. The equilibrium of the balance arm can be adjusted with nuts on screws located at both sides of the balance arm. Transducer was mounted to bottom of water tank. Absorbers in the bottom and the near walls of the tank were used for reflecting target case. Ultrasound power was applied to one scale of the balance where the reflecting/absorbing target was mounted and corresponding force was measured on the other scale of balance where was connected to a balance with a thin wire while the thin rest standing on a support. Ultrasound power of two HITU transducers at frequencies 0.93 MHz, 1.1 MHz and 3.3 MHz were measured with conventional and new system, the values were compared and uncertainty components were assessed in this paper.

  13. Radiatively-driven winds: model improvements, ionization balance and the infared spectrum

    International Nuclear Information System (INIS)

    Castor, J.I.

    1979-01-01

    Recent improvements to theoretical stellar wind models and the results of empirical modelling of the ionization balance and the infrared continuum are discussed. The model of a wind driven by radiation pressure in spectral lines is improved by accounting for overlap of the driving lines, dependence of ionization balance on density, and stellar rotation. These effects produce a softer velocity law than that given by Castor, Abbott and Klein (1975). The ionization balance in zeta Puppis is shown to agree with that estimated for an optically thick wind at a gas temperature of 60,000 K. The ionization model is not unique. The infrared continuum of zeta Pup measured by Barlow and Cohen is fitted to a cool model with a linear rise of velocity with radius; this fit is also not unique. It is concluded that one should try to find a model that fits several kinds of evidence simultaneously. (Auth.)

  14. Planetary and Space Simulation Facilities PSI at DLR for Astrobiology

    Science.gov (United States)

    Rabbow, E.; Rettberg, P.; Panitz, C.; Reitz, G.

    2008-09-01

    Ground based experiments, conducted in the controlled planetary and space environment simulation facilities PSI at DLR, are used to investigate astrobiological questions and to complement the corresponding experiments in LEO, for example on free flying satellites or on space exposure platforms on the ISS. In-orbit exposure facilities can only accommodate a limited number of experiments for exposure to space parameters like high vacuum, intense radiation of galactic and solar origin and microgravity, sometimes also technically adapted to simulate extraterrestrial planetary conditions like those on Mars. Ground based experiments in carefully equipped and monitored simulation facilities allow the investigation of the effects of simulated single environmental parameters and selected combinations on a much wider variety of samples. In PSI at DLR, international science consortia performed astrobiological investigations and space experiment preparations, exposing organic compounds and a wide range of microorganisms, reaching from bacterial spores to complex microbial communities, lichens and even animals like tardigrades to simulated planetary or space environment parameters in pursuit of exobiological questions on the resistance to extreme environments and the origin and distribution of life. The Planetary and Space Simulation Facilities PSI of the Institute of Aerospace Medicine at DLR in Köln, Germany, providing high vacuum of controlled residual composition, ionizing radiation of a X-ray tube, polychromatic UV radiation in the range of 170-400 nm, VIS and IR or individual monochromatic UV wavelengths, and temperature regulation from -20°C to +80°C at the sample size individually or in selected combinations in 9 modular facilities of varying sizes are presented with selected experiments performed within.

  15. Long-Term Planetary Habitability and the Carbonate-Silicate Cycle.

    Science.gov (United States)

    Rushby, Andrew J; Johnson, Martin; Mills, Benjamin J W; Watson, Andrew J; Claire, Mark W

    2018-05-01

    The potential habitability of an exoplanet is traditionally assessed by determining whether its orbit falls within the circumstellar "habitable zone" of its star, defined as the distance at which water could be liquid on the surface of a planet (Kopparapu et al., 2013 ). Traditionally, these limits are determined by radiative-convective climate models, which are used to predict surface temperatures at user-specified levels of greenhouse gases. This approach ignores the vital question of the (bio)geochemical plausibility of the proposed chemical abundances. Carbon dioxide is the most important greenhouse gas in Earth's atmosphere in terms of regulating planetary temperature, with the long-term concentration controlled by the balance between volcanic outgassing and the sequestration of CO 2 via chemical weathering and sedimentation, as modulated by ocean chemistry, circulation, and biological (microbial) productivity. We developed a model that incorporates key aspects of Earth's short- and long-term biogeochemical carbon cycle to explore the potential changes in the CO 2 greenhouse due to variance in planet size and stellar insolation. We find that proposed changes in global topography, tectonics, and the hydrological cycle on larger planets result in proportionally greater surface temperatures for a given incident flux. For planets between 0.5 and 2 R ⊕ , the effect of these changes results in average global surface temperature deviations of up to 20 K, which suggests that these relationships must be considered in future studies of planetary habitability. Key Words: Planets-Atmospheres-Carbon dioxide-Biogeochemistry. Astrobiology 18, 469-480.

  16. Planetary nebulae

    International Nuclear Information System (INIS)

    Amnuehl', P.R.

    1985-01-01

    The history of planetary nebulae discovery and their origin and evolution studies is discussed in a popular way. The problem of planetary nebulae central star is considered. The connection between the white-draft star and the planetary nebulae formulation is shown. The experimental data available acknowledge the hypothesis of red giant - planetary nebula nucleus - white-draft star transition process. Masses of planetary nebulae white-draft stars and central stars are distributed practically similarly: the medium mass is close to 0.6Msub(Sun) (Msub(Sun) - is the mass of the Sun)

  17. Surface energy and radiation balance systems - General description and improvements

    Science.gov (United States)

    Fritschen, Leo J.; Simpson, James R.

    1989-01-01

    Surface evaluation of sensible and latent heat flux densities and the components of the radiation balance were desired for various vegetative surfaces during the ASCOT84 experiment to compare with modeled results and to relate these values to drainage winds. Five battery operated data systems equipped with sensors to determine the above values were operated for 105 station days during the ASCOT84 experiment. The Bowen ratio energy balance technique was used to partition the available energy into the sensible and latent heat flux densities. A description of the sensors and battery operated equipment used to collect and process the data is presented. In addition, improvements and modifications made since the 1984 experiment are given. Details of calculations of soil heat flow at the surface and an alternate method to calculate sensible and latent heat flux densities are provided.

  18. SPEX: the Spectropolarimeter for Planetary Exploration

    Science.gov (United States)

    Rietjens, J. H. H.; Snik, F.; Stam, D. M.; Smit, J. M.; van Harten, G.; Keller, C. U.; Verlaan, A. L.; Laan, E. C.; ter Horst, R.; Navarro, R.; Wielinga, K.; Moon, S. G.; Voors, R.

    2017-11-01

    We present SPEX, the Spectropolarimeter for Planetary Exploration, which is a compact, robust and low-mass spectropolarimeter designed to operate from an orbiting or in situ platform. Its purpose is to simultaneously measure the radiance and the state (degree and angle) of linear polarization of sunlight that has been scattered in a planetary atmosphere and/or reflected by a planetary surface with high accuracy. The degree of linear polarization is extremely sensitive to the microphysical properties of atmospheric or surface particles (such as size, shape, and composition), and to the vertical distribution of atmospheric particles, such as cloud top altitudes. Measurements as those performed by SPEX are therefore crucial and often the only tool for disentangling the many parameters that describe planetary atmospheres and surfaces. SPEX uses a novel, passive method for its radiance and polarization observations that is based on a carefully selected combination of polarization optics. This method, called spectral modulation, is the modulation of the radiance spectrum in both amplitude and phase by the degree and angle of linear polarization, respectively. The polarization optics consists of an achromatic quarter-wave retarder, an athermal multiple-order retarder, and a polarizing beam splitter. We will show first results obtained with the recently developed prototype of the SPEX instrument, and present a performance analysis based on a dedicated vector radiative transport model together with a recently developed SPEX instrument simulator.

  19. From Science Reserves to Sustainable Multiple Uses beyond Earth orbit: Evaluating Issues on the Path towards Balanced Environmental Management on Planetary Bodies

    Science.gov (United States)

    Race, Margaret

    Over the past five decades, our understanding of space beyond Earth orbit has been shaped by a succession of mainly robotic missions whose technologies have enabled scientists to answer diverse science questions about celestial bodies across the solar system. For all that time, exploration has been guided by planetary protection policies and principles promulgated by COSPAR and based on provisions in Article IX of the Outer Space Treaty of 1967. Over time, implementation of the various COSPAR planetary protection policies have sought to avoid harmful forward and backward contamination in order to ensure the integrity of science findings, guide activities on different celestial bodies, and appropriately protect Earth whenever extraterrestrial materials have been returned. The recent increased interest in extending both human missions and commercial activities beyond Earth orbit have prompted discussions in various quarters about the need for updating policies and guidelines to ensure responsible, balanced space exploration and use by all parties, regardless whether activities are undertaken by governmental or non-governmental entities. Already, numerous researchers and workgroups have suggested a range of different ways to manage activities on celestial environments (e.g, wilderness parks, exclusion zones, special regions, claims, national research bases, environmental impact assessments, etc.). While the suggestions are useful in thinking about how to manage future space activities, they are not based on any systematically applied or commonly accepted criteria (scientific or otherwise). In addition, they are borrowed from terrestrial approaches for environmental protection, which may or may not have direct applications to space environments. As noted in a recent COSPAR-PEX workshop (GWU 2012), there are no clear definitions of issues such as harmful contamination, the environment to be protected, or what are considered reasonable activity or impacts for particular

  20. On the Meaning of Feedback Parameter, Transient Climate Response, and the Greenhouse Effect: Basic Considerations and the Discussion of Uncertainties

    Science.gov (United States)

    Kramm, Gerhard

    2010-07-01

    In this paper we discuss the meaning of feedback parameter, greenhouse effect and transient climate response usually related to the globally averaged energy balance model of Schneider and Mass. After scrutinizing this model and the corresponding planetary radiation balance we state that (a) the this globally averaged energy balance model is flawed by unsuitable physical considerations, (b) the planetary radiation balance for an Earth in the absence of an atmosphere is fraught by the inappropriate assumption of a uniform surface temperature, the so-called radiative equilibrium temperature of about 255 K, and (c) the effect of the radiative anthropogenic forcing, considered as a perturbation to the natural system, is much smaller than the uncertainty involved in the solution of the model of Schneider and Mass. This uncertainty is mainly related to the empirical constants suggested by various authors and used for predicting the emission of infrared radiation by the Earth's skin. Furthermore, after inserting the absorption of solar radiation by atmospheric constituents and the exchange of sensible and latent heat between the Earth and the atmosphere into the model of Schneider and Mass the surface temperatures become appreciably lesser than the radiative equilibrium temperature. Moreover, neither the model of Schneider and Mass nor the Dines-type two-layer energy balance model for the Earth-atmosphere system, both contain the planetary radiation balance for an Earth in the absence of an atmosphere as an asymptotic solution, do not provide evidence for the existence of the so-called atmospheric greenhouse effect if realistic empirical data are used.

  1. Time-dependent simulations of disk-embedded planetary atmospheres

    Science.gov (United States)

    Stökl, A.; Dorfi, E. A.

    2014-03-01

    At the early stages of evolution of planetary systems, young Earth-like planets still embedded in the protoplanetary disk accumulate disk gas gravitationally into planetary atmospheres. The established way to study such atmospheres are hydrostatic models, even though in many cases the assumption of stationarity is unlikely to be fulfilled. Furthermore, such models rely on the specification of a planetary luminosity, attributed to a continuous, highly uncertain accretion of planetesimals onto the surface of the solid core. We present for the first time time-dependent, dynamic simulations of the accretion of nebula gas into an atmosphere around a proto-planet and the evolution of such embedded atmospheres while integrating the thermal energy budget of the solid core. The spherical symmetric models computed with the TAPIR-Code (short for The adaptive, implicit RHD-Code) range from the surface of the rocky core up to the Hill radius where the surrounding protoplanetary disk provides the boundary conditions. The TAPIR-Code includes the hydrodynamics equations, gray radiative transport and convective energy transport. The results indicate that diskembedded planetary atmospheres evolve along comparatively simple outlines and in particular settle, dependent on the mass of the solid core, at characteristic surface temperatures and planetary luminosities, quite independent on numerical parameters and initial conditions. For sufficiently massive cores, this evolution ultimately also leads to runaway accretion and the formation of a gas planet.

  2. Proto-planetary nebulae

    International Nuclear Information System (INIS)

    Zuckerman, B.

    1978-01-01

    A 'proto-planetary nebula' or a 'planetary nebula progenitor' is the term used to describe those objects that are losing mass at a rate >approximately 10 -5 Msolar masses/year (i.e. comparable to mass loss rates in planetary nebulae with ionized masses >approximately 0.2 Msolar masses) and which, it is believed, will become planetary nebulae themselves within 5 years. It is shown that most proto-planetary nebulae appear as very red objects although a few have been 'caught' near the middle of the Hertzsprung-Russell diagram. The precursors of these proto-planetaries are the general red giant population, more specifically probably Mira and semi-regular variables. (Auth.)end

  3. Relating Radiative Fluxes on Arctic Sea Ice Area Using Arctic Observation and Reanalysis Integrated System (ArORIS)

    Science.gov (United States)

    Sledd, A.; L'Ecuyer, T. S.

    2017-12-01

    With Arctic sea ice declining rapidly and Arctic temperatures rising faster than the rest of the globe, a better understanding of the Arctic climate, and ice cover-radiation feedbacks in particular, is needed. Here we present the Arctic Observation and Reanalysis Integrated System (ArORIS), a dataset of integrated products to facilitate studying the Arctic using satellite, reanalysis, and in-situ datasets. The data include cloud properties, radiative fluxes, aerosols, meteorology, precipitation, and surface properties, to name just a few. Each dataset has uniform grid-spacing, time-averaging and naming conventions for ease of use between products. One intended use of ArORIS is to assess Arctic radiation and moisture budgets. Following that goal, we use observations from ArORIS - CERES-EBAF radiative fluxes and NSIDC sea ice fraction and area to quantify relationships between the Arctic energy balance and surface properties. We find a discernable difference between energy budgets for years with high and low September sea ice areas. Surface fluxes are especially responsive to the September sea ice minimum in months both leading up to September and the months following. In particular, longwave fluxes at the surface show increased sensitivity in the months preceding September. Using a single-layer model of solar radiation we also investigate the individual responses of surface and planetary albedos to changes in sea ice area. By partitioning the planetary albedo into surface and atmospheric contributions, we find that the atmospheric contribution to planetary albedo is less sensitive to changes in sea ice area than the surface contribution. Further comparisons between observations and reanalyses can be made using the available datasets in ArORIS.

  4. Radiation balance at the surface in the city of São Paulo, Brazil: diurnal and seasonal variations

    NARCIS (Netherlands)

    Ferreira, M.J.; Oliveira, de A.P.; Soares, J.; Codato, G.; Wilde Barbaro, E.; Escobedo, J.F.

    2012-01-01

    The main goal of this work is to describe the diurnal and seasonal variations of the radiation balance components at the surface in the city of São Paulo based on observations carried out during 2004. Monthly average hourly values indicate that the amplitudes of the diurnal cycles of net radiation

  5. A New Radio Spectral Line Survey of Planetary Nebulae: Exploring Radiatively Driven Heating and Chemistry of Molecular Gas

    Science.gov (United States)

    Bublitz, Jesse

    Planetary nebulae contain shells of cold gas and dust whose heating and chemistry is likely driven by UV and X-ray emission from their central stars and from wind-collision-generated shocks. We present the results of a survey of molecular line emissions in the 88 - 235 GHz range from nine nearby (Radioastronomie Millimetrique. Rotational transitions of nine molecules, including the well-studied CO isotopologues and chemically important trace species, were observed and the results compared with and augmented by previous studies of molecular gas in PNe. Lines of the molecules HCO+, HNC, HCN, and CN, which were detected in most objects, represent new detections for five planetary nebulae in our study. Flux ratios were analyzed to identify correlations between the central star and/or nebular ultraviolet/X-ray luminosities and the molecular chemistries of the nebulae. Analysis reveals the apparent dependence of the HNC/HCN line ratio on PN central star UV luminosity. There exists no such clear correlation between PN X-rays and various diagnostics of PN molecular chemistry. The correlation between HNC/HCN ratio and central star UV luminosity hints at the potential of molecular emission line studies of PNe for improving our understanding of the role that high-energy radiation plays in the heating and chemistry of photodissociation regions.

  6. Određivanje krutosti planetarnog prenosnika / Determination of gear mesh stiffness in planetary gearing

    Directory of Open Access Journals (Sweden)

    Vojislav Batinić

    2008-04-01

    Full Text Available Kontaktna krutost zubaca jedan je od glavnih generatora unutrašnjih dinamičkih sila u spregama zupčanika planetarnih prenosnika. Neophodan je pri opisivanju dinamičkog ponašanja planetarnih prenosnika, tj. pri postavljanju jednačina dinamičke ravnoteže. U radu je prikazan metodološki pristup analitičkom i eksperimentalnom određivanju krutosti posmatranog planetarnog prenosnika. / Gear mesh stiffness in planetary gearing is one of the main generators of internal dynamic forces. It is necessary in describing dynamic behavior of planetary trains, i.e. in defining their equations of dynamic balance. This paper presents a methodological approach to experimental and analytical calculation of stiffness in planetary gearing.

  7. Planetary Radar

    Science.gov (United States)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

    This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

  8. From Planetary Mapping to Map Production: Planetary Cartography as integral discipline in Planetary Sciences

    Science.gov (United States)

    Nass, Andrea; van Gasselt, Stephan; Hargitai, Hendrik; Hare, Trent; Manaud, Nicolas; Karachevtseva, Irina; Kersten, Elke; Roatsch, Thomas; Wählisch, Marita; Kereszturi, Akos

    2016-04-01

    Cartography is one of the most important communication channels between users of spatial information and laymen as well as the open public alike. This applies to all known real-world objects located either here on Earth or on any other object in our Solar System. In planetary sciences, however, the main use of cartography resides in a concept called planetary mapping with all its various attached meanings: it can be (1) systematic spacecraft observation from orbit, i.e. the retrieval of physical information, (2) the interpretation of discrete planetary surface units and their abstraction, or it can be (3) planetary cartography sensu strictu, i.e., the technical and artistic creation of map products. As the concept of planetary mapping covers a wide range of different information and knowledge levels, aims associated with the concept of mapping consequently range from a technical and engineering focus to a scientific distillation process. Among others, scientific centers focusing on planetary cartography are the United State Geological Survey (USGS, Flagstaff), the Moscow State University of Geodesy and Cartography (MIIGAiK, Moscow), Eötvös Loránd University (ELTE, Hungary), and the German Aerospace Center (DLR, Berlin). The International Astronomical Union (IAU), the Commission Planetary Cartography within International Cartographic Association (ICA), the Open Geospatial Consortium (OGC), the WG IV/8 Planetary Mapping and Spatial Databases within International Society for Photogrammetry and Remote Sensing (ISPRS) and a range of other institutions contribute on definition frameworks in planetary cartography. Classical cartography is nowadays often (mis-)understood as a tool mainly rather than a scientific discipline and an art of communication. Consequently, concepts of information systems, mapping tools and cartographic frameworks are used interchangeably, and cartographic workflows and visualization of spatial information in thematic maps have often been

  9. Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

    Science.gov (United States)

    Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

    2013-10-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere.

  10. Radiation losses and global energy balance for Ohmically heated discharges in ASDEX

    International Nuclear Information System (INIS)

    Mueller, E.R.; Behringer, K.; Niedermeyer, H.

    1982-01-01

    Global energy balance, radiation profiles and dominant impurity radiation sources are compared for Ohmically heated limiter and divertor discharges in the ASDEX tokamak. In discharges with a poloidal stainless-steel limiter, total radiation from the plasma is the dominant energy loss channel. The axisymmetric divertor reduces this volume-integrated radiation to 30-35% of the heating power and additional Ti-gettering halves it again to 10-15%. Local radiation losses in the plasma centre, which are mainly due to the presence of iron impurity ions, are reduced by about one order of magnitude. In high-current (Isub(p) = 400 kA) and high-density (nsub(e)-bar = 6 x 10 13 cm -3 ) ungettered divertor discharges, up to 55% of the heating power is dumped into a cold-gas target inside the divertor chambers. The bolometrically detected volume power losses in the chambers can mainly be attributed to neutral hydrogen atoms with kinetic energies of a few eV. In this parameter range, the divertor plasma is dominated by inelastic molecular and atomic processes, the main process being Franck-Condon dissociation of H 2 molecules. (author)

  11. Solving the radiation diffusion and energy balance equations using pseudo-transient continuation

    International Nuclear Information System (INIS)

    Shestakov, A.I.; Greenough, J.A.; Howell, L.H.

    2005-01-01

    We develop a scheme for the system coupling the radiation diffusion and matter energy balance equations. The method is based on fully implicit, first-order, backward Euler differencing; Picard-Newton iterations solve the nonlinear system. We show that iterating on the radiation energy density and the emission source is more robust. Since the Picard-Newton scheme may not converge for all initial conditions and time steps, pseudo-transient continuation (Ψtc) is introduced. The combined Ψtc-Picard-Newton scheme is analyzed. We derive conditions on the Ψtc parameter that guarantee physically meaningful iterates, e.g., positive energies. Successive Ψtc iterates are bounded and the radiation energy density and emission source tend to equilibrate. The scheme is incorporated into a multiply dimensioned, massively parallel, Eulerian, radiation-hydrodynamic computer program with automatic mesh refinement (AMR). Three examples are presented that exemplify the scheme's performance. (1) The Pomraning test problem that models radiation flow into cold matter. (2) A similar, but more realistic problem simulating the propagation of an ionization front into tenuous hydrogen gas with a Saha model for the equation-of-state. (3) A 2D axisymmetric (R,Z) simulation with real materials featuring jetting, radiatively driven, interacting shocks

  12. Radiation dose in mammography: an energy-balance approach

    International Nuclear Information System (INIS)

    Shrivastava, P.N.

    1981-01-01

    An energy-balance approach for calculation of mean, integral, and midpoint doses in mammography is introduced. Estimation of mean absorbed dose for individual applications is described. Calculations made for a range of xeromammographic techniques used at various breast cancer detection centers show that although increasing the beam h.v.l. dramatically decreases breast surface exposure, it is insignificant in lowering mean breast dose or radiation risk. Thus selection of a moderate h.v.l. to optimize image quality in xeromammography may be more beneficial than unduly increasing h.v.l. merely to reduce surface exposure. The mean breast dose per mammogram with low h.v.l. screen-film techniques was 3 to 9 times lower than for xeromammography, suggesting that general acceptance of screen-film techniques can significantly reduce the risk associated with mammography

  13. The circulation pattern and day-night heat transport in the atmosphere of a synchronously rotating aquaplanet: Dependence on planetary rotation rate

    Science.gov (United States)

    Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Takehiro, S.; Onishi, M.; Hashimoto, G. L.; Kuramoto, K.; Hayashi, Y.-Y.

    2017-01-01

    In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aquaplanet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-III to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the

  14. Shaping of planetary nebulae

    International Nuclear Information System (INIS)

    Balick, B.

    1987-01-01

    The phases of stellar evolution and the development of planetary nebulae are examined. The relation between planetary nebulae and red giants is studied. Spherical and nonspherical cases of shaping planetaries with stellar winds are described. CCD images of nebulae are analyzed, and it is determined that the shape of planetary nebulae depends on ionization levels. Consideration is given to calculating the distances of planetaries using radio images, and molecular hydrogen envelopes which support the wind-shaping model of planetary nebulae

  15. Planetary Magnetism

    Science.gov (United States)

    Connerney, J. E. P.

    2007-01-01

    The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

  16. Radiative Transfer of Solar Light in Dense Complex Media : Theoretical and Experimental Achievements by the Planetary Community

    Science.gov (United States)

    Doute, S.; Schmitt, B.

    2004-05-01

    Visible and near infrared imaging spectroscopy is one of the key techniques to detect, map and characterize mineral and volatile species existing at the surface of the planets. Indeed the chemical composition, granularity, texture, physical state, etc, of the materials determine the existence and morphology of the absorption bands. However the development of quantitative methods to analyze reflectance spectra requires mastering of a very challenging physics: the reflection of solar light by densely packed, absorbent and highly scattering materials that usually present a fantastic structural complexity at different spatial scales. Volume scattering of photons depends on many parameters like the intrinsic optical properties, the shapes, sizes and the packing density of the mineral or icy grains forming the natural media. Their discontinuous and stochastic nature plays a great role especially for reflection and shading by the top few grains of the surface. Over several decades, the planetary community has developed increasingly sophisticated tools to handle this problem of radiative transfer in dense complex media in order to fulfill its needs. Analytical functions with a small number of non physical adjusting parameters were first proposed to reproduce the photometry of the planets and satellites. Then reflectance models were built by implementing methods of radiative transfer in continuously absorbent and scattering medium. A number of very restricting hypothesis forms the basis of these methods, e.g. low particles density, scattering treated in the far field approximation. A majority of these assumptions does not stand when treating planetary regoliths or volatile deposits. In addition, the classical methods completely bypass effects due to the constructive interference of scattered waves for backscattering or specular geometries (e.g. the opposition effect). Different, sometimes competing, approaches have been proposed to overcome some of these limitations. In

  17. Europlanet Research Infrastructure: Planetary Simulation Facilities

    Science.gov (United States)

    Davies, G. R.; Mason, N. J.; Green, S.; Gómez, F.; Prieto, O.; Helbert, J.; Colangeli, L.; Srama, R.; Grande, M.; Merrison, J.

    2008-09-01

    EuroPlanet The Europlanet Research Infrastructure consortium funded under FP7 aims to provide the EU Planetary Science community greater access for to research infrastructure. A series of networking and outreach initiatives will be complimented by joint research activities and the formation of three Trans National Access distributed service laboratories (TNA's) to provide a unique and comprehensive set of analogue field sites, laboratory simulation facilities, and extraterrestrial sample analysis tools. Here we report on the infrastructure that comprises the second TNA; Planetary Simulation Facilities. 11 laboratory based facilities are able to recreate the conditions found in the atmospheres and on the surfaces of planetary systems with specific emphasis on Martian, Titan and Europa analogues. The strategy has been to offer some overlap in capabilities to ensure access to the highest number of users and to allow for progressive and efficient development strategies. For example initial testing of mobility capability prior to the step wise development within planetary atmospheres that can be made progressively more hostile through the introduction of extreme temperatures, radiation, wind and dust. Europlanet Research Infrastructure Facilties: Mars atmosphere simulation chambers at VUA and OU These relatively large chambers (up to 1 x 0.5 x 0.5 m) simulate Martian atmospheric conditions and the dual cooling options at VUA allows stabilised instrument temperatures while the remainder of the sample chamber can be varied between 220K and 350K. Researchers can therefore assess analytical protocols for instruments operating on Mars; e.g. effect of pCO2, temperature and material (e.g., ± ice) on spectroscopic and laser ablation techniques while monitoring the performance of detection technologies such as CCD at low T & variable p H2O & pCO2. Titan atmosphere and surface simulation chamber at OU The chamber simulates Titan's atmospheric composition under a range of

  18. Nonlinear Dynamic Analysis and Optimization of Closed-Form Planetary Gear System

    Directory of Open Access Journals (Sweden)

    Qilin Huang

    2013-01-01

    Full Text Available A nonlinear purely rotational dynamic model of a multistage closed-form planetary gear set formed by two simple planetary stages is proposed in this study. The model includes time-varying mesh stiffness, excitation fluctuation and gear backlash nonlinearities. The nonlinear differential equations of motion are solved numerically using variable step-size Runge-Kutta. In order to obtain function expression of optimization objective, the nonlinear differential equations of motion are solved analytically using harmonic balance method (HBM. Based on the analytical solution of dynamic equations, the optimization mathematical model which aims at minimizing the vibration displacement of the low-speed carrier and the total mass of the gear transmission system is established. The optimization toolbox in MATLAB program is adopted to obtain the optimal solution. A case is studied to demonstrate the effectiveness of the dynamic model and the optimization method. The results show that the dynamic properties of the closed-form planetary gear transmission system have been improved and the total mass of the gear set has been decreased significantly.

  19. Planetary magnetospheres

    International Nuclear Information System (INIS)

    Hill, T.W.; Michel, F.C.

    1975-01-01

    Recent planetary probes have resulted in the realization of the generality of magnetospheric interactions between the solar wind and the planets. The three categories of planetary magnetospheres are discussed: intrinsic slowly rotating magnetospheres, intrinsic rapidly rotating magnetospheres, and induced magnetospheres. (BJG)

  20. On Some General Regularities of Formation of the Planetary Systems

    Directory of Open Access Journals (Sweden)

    Belyakov A. V.

    2014-01-01

    Full Text Available J.Wheeler’s geometrodynamic concept has been used, in which space continuum is considered as a topologically non-unitary coherent surface admitting the existence of transitions of the input-output kind between distant regions of the space in an additional dimension. This model assumes the existence of closed structures (micro- and macro- contours formed due to the balance between main interactions: gravitational, electric, magnetic, and inertial forces. It is such macrocontours that have been demonstrated to form — independently of their material basis — the essential structure of objects at various levels of organization of matter. On the basis of this concept in this paper basic regularities acting during formation planetary systems have been obtained. The existence of two sharply different types of planetary systems has been determined. The dependencies linking the masses of the planets, the diameters of the planets, the orbital radii of the planet, and the mass of the central body have been deduced. The possibility of formation of Earth-like planets near brown dwarfs has been grounded. The minimum mass of the planet, which may arise in the planetary system, has been defined.

  1. Simulations of GCR interactions within planetary bodies using GEANT4

    Science.gov (United States)

    Mesick, K.; Feldman, W. C.; Stonehill, L. C.; Coupland, D. D. S.

    2017-12-01

    On planetary bodies with little to no atmosphere, Galactic Cosmic Rays (GCRs) can hit the body and produce neutrons primarily through nuclear spallation within the top few meters of the surfaces. These neutrons undergo further nuclear interactions with elements near the planetary surface and some will escape the surface and can be detected by landed or orbiting neutron radiation detector instruments. The neutron leakage signal at fast neutron energies provides a measure of average atomic mass of the near-surface material and in the epithermal and thermal energy ranges is highly sensitive to the presence of hydrogen. Gamma-rays can also escape the surface, produced at characteristic energies depending on surface composition, and can be detected by gamma-ray instruments. The intra-nuclear cascade (INC) that occurs when high-energy GCRs interact with elements within a planetary surface to produce the leakage neutron and gamma-ray signals is highly complex, and therefore Monte Carlo based radiation transport simulations are commonly used for predicting and interpreting measurements from planetary neutron and gamma-ray spectroscopy instruments. In the past, the simulation code that has been widely used for this type of analysis is MCNPX [1], which was benchmarked against data from the Lunar Neutron Probe Experiment (LPNE) on Apollo 17 [2]. In this work, we consider the validity of the radiation transport code GEANT4 [3], another widely used but open-source code, by benchmarking simulated predictions of the LPNE experiment to the Apollo 17 data. We consider the impact of different physics model options on the results, and show which models best describe the INC based on agreement with the Apollo 17 data. The success of this validation then gives us confidence in using GEANT4 to simulate GCR-induced neutron leakage signals on Mars in relevance to a re-analysis of Mars Odyssey Neutron Spectrometer data. References [1] D.B. Pelowitz, Los Alamos National Laboratory, LA-CP-05

  2. Radiation dose in mammography: an energy-balance approach

    International Nuclear Information System (INIS)

    Shrivastava, P.N.

    1981-01-01

    An energy-balance approach for calculation of mean, integral, and midpoint doses in mammography is introduced. Estimation of mean absorbed dose for individual applications is described. Differences in breast composition and thickness are accounted for by simple measurements of entrance and exit exposures. Calculations made for a range of xeromammographic techniques used at various breast cancer detection centers show that although increasing the beam h.v.l. dramatically decreases breast surface exposure, it is insignificant in lowering mean breast dose or radiation risk. Thus selection of a moderate h.v.l. to optimize image quality (soft-tissue contrast) in xeromammography may be more beneficial than unduly increasing h.v.l. merely to reduce surface exposure. The mean breast dose per mammogram with low-h.v.l. screen-film techniques was 3 to 9 times lower than for xeromammography, suggesting that general acceptance of screen-film techniques can significantly reduce the risk associated with mammography

  3. Solar radiation and energy balance in polyethylene covered greenhouse; Balancos de radiacao solar e de energia em estufa com cobertura de polietileno

    Energy Technology Data Exchange (ETDEWEB)

    Frisina, Valeria de Almeida; Escobedo, Joao Francisco [UNESP, Botucatu, SP (Brazil). Faculdade de Ciencias Agronomicas. Dept. de Ciencias Ambientais

    1998-07-01

    The objective of this paper is describe the radiation and energy balance, during the lettuce (Lactuca sativa, L, var Veronica) crop cycle inside a polyethylene greenhouse. The radiation and energy balance was made inside of a tunnel greenhouse with polyethylene cover (100 {mu} m) and in an external area, both area with 35 m{sup 2}. Global (R{sub G}), reflected (R{sub r}) and net radiation (SR), soil heat flux and air temperature (dry and humid) were measured during crop cycle, in this two environment. In the data acquisition it was utilized a DATALOGGER, which operated at 1 Hz frequency, storing 5 minutes averages. The global and reflected radiations (MJ/m{sup 2}) allowed the verification that the average transmission of global radiation (R-G{sub in}/R{sub Gex}) was almost constant, near 79,59% while the average ratio of reflected radiation (R{sub rin}/R{sub rex}) was 69,21% with 8,47% standard-deviation. The short-wave radiation average (SRoc) was bigger in the external area. The normalized relation (SR/R{sub G}) was bigger in the external area, about 12%, when the green culture covered (SRol) was bigger outside, about 50%. The energy balance, estimated in terms of vertical fluxes, showed that, for the external area, in average, 83,07% of total net radiation was converted in latent heat evaporation; 18% in soil heat flux and 9,96% in sensible heat, while, inside of the greenhouse, 58,71% of total net radiation was converted in latent heat evaporation:; 42,68% in sensible heat and 28,79% in soil heat flux. (author)

  4. Comparative analysis of different approaches to the computation of long-wave radiation balance of water air systems

    International Nuclear Information System (INIS)

    Zhukovskii, K.; Nourani, Y.; Monte, L.

    1999-01-01

    In the present paper, the net long-wave radiation balance of the water-air environmental systems is analysed on the base of several semi-empirical approaches. Various theoretical models of infrared atmospheric radiation are reviewed. Factors, affecting their behavior are considered. Special attention is paid to physical conditions under which those models are applicable. Atmospheric and net infrared radiation fluxes are computed and compared under clear and cloudy sky. Results are presented in graphical form. Conclusions are made on the applicability of models considered for evaluating infrared radiation fluxes in environmental conditions of Central Italy. On the base of present analysis Anderson's model is chosen for future calculations of heat budget of lakes in Central Italy [it

  5. Luminosity function for planetary nebulae and the number of planetary nebulae in local group galaxies

    International Nuclear Information System (INIS)

    Jacoby, G.H.

    1980-01-01

    Identifications of 19 and 34 faint planetary nebulae have been made in the central regions of the SMC and LMC, respectively, using on-line/off-line filter photography at [O III] and Hα. The previously known brighter planetary nebulae in these fields, eight in both the SMC and the LMC, were also identified. On the basis of the ratio of the numbers of faint to bright planetary nebulae in these fields and the numbers of bright planetary nebulae in the surrounding fields, the total numbers of planetary nebulae in the SMC and LMC are estimated to be 285 +- 78 and 996 +- 253, respectively. Corrections have been applied to account for omissions due to crowding confusion in previous surveys, spatial and detectability incompleteness, and obscuration by dust.Equatorial coordinates and finding charts are presented for all the identified planetary nebulae. The coordinates have uncertainties smaller than 0.''6 relative to nearby bright stars, thereby allowing acquisition of the planetary nebulae by bling offsetting.Monochromatic fluxes are derived photographically and used to determine the luminosity function for Magellanic Cloud planetary nebulae as faint as 6 mag below the brightest. The luminosity function is used to estimate the total numbers of planetary nebulae in eight Local Group galaxies in which only bright planetary nebulae have been identified. The dervied luminosity specific number of planetary nebulae per unit luminosity is nearly constant for all eight galaxies, having a value of 6.1 x 10 -7 planetary nebulae L -1 /sub sun/. The mass specific number, based on the three galaxies with well-determined masses, is 2.1 x 10 -7 planetary nebulae M -1 /sub sun/. With estimates for the luminosity and mass of our Galaxy, its total number of planetary nebulae is calculated to be 10,000 +- 4000, in support of the Cudworth distance scale

  6. The Role of NASA's Planetary Data System in the Planetary Spatial Data Infrastructure Initiative

    Science.gov (United States)

    Arvidson, R. E.; Gaddis, L. R.

    2017-12-01

    An effort underway in NASA's planetary science community is the Mapping and Planetary Spatial Infrastructure Team (MAPSIT, http://www.lpi.usra.edu/mapsit/). MAPSIT is a community assessment group organized to address a lack of strategic spatial data planning for space science and exploration. Working with MAPSIT, a new initiative of NASA and USGS is the development of a Planetary Spatial Data Infrastructure (PSDI) that builds on extensive knowledge on storing, accessing, and working with terrestrial spatial data. PSDI is a knowledge and technology framework that enables the efficient discovery, access, and exploitation of planetary spatial data to facilitate data analysis, knowledge synthesis, and decision-making. NASA's Planetary Data System (PDS) archives >1.2 petabytes of digital data resulting from decades of planetary exploration and research. The PDS charter focuses on the efficient collection, archiving, and accessibility of these data. The PDS emphasis on data preservation and archiving is complementary to that of the PSDI initiative because the latter utilizes and extends available data to address user needs in the areas of emerging technologies, rapid development of tailored delivery systems, and development of online collaborative research environments. The PDS plays an essential PSDI role because it provides expertise to help NASA missions and other data providers to organize and document their planetary data, to collect and maintain the archives with complete, well-documented and peer-reviewed planetary data, to make planetary data accessible by providing online data delivery tools and search services, and ultimately to ensure the long-term preservation and usability of planetary data. The current PDS4 information model extends and expands PDS metadata and relationships between and among elements of the collections. The PDS supports data delivery through several node services, including the Planetary Image Atlas (https

  7. Comparative Climates of the Trappist-1 Planetary System: Results from a Simple Climate-vegetation Model

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, Tommaso; Carbone, Vincenzo; Lepreti, Fabio [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, I-87036, Rende (CS) (Italy); Vecchio, Antonio, E-mail: tommaso.alberti@unical.it, E-mail: tommasoalberti89@gmail.com [LESIA—Observatoire de Paris, PSL Research University, 5 place Jules Janssen, F-92190, Meudon (France)

    2017-07-20

    The recent discovery of the planetary system hosted by the ultracool dwarf star TRAPPIST-1 could open new paths for investigations of the planetary climates of Earth-sized exoplanets, their atmospheres, and their possible habitability. In this paper, we use a simple climate-vegetation energy-balance model to study the climate of the seven TRAPPIST-1 planets and the climate dependence on various factors: the global albedo, the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions. The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a “surface water zone (SWZ)”) in different planetary conditions, with or without the presence of a greenhouse effect. It is shown that planet TRAPPIST-1d seems to be the most stable from an Earth-like perspective, since it resides in the SWZ for a wide range of reasonable values of the model parameters. Moreover, according to the model, outer planets (f, g, and h) cannot host liquid water on their surfaces, even with Earth-like conditions, entering a snowball state. Although very simple, the model allows us to extract the main features of the TRAPPIST-1 planetary climates.

  8. Comparative Climates of the Trappist-1 Planetary System: Results from a Simple Climate-vegetation Model

    International Nuclear Information System (INIS)

    Alberti, Tommaso; Carbone, Vincenzo; Lepreti, Fabio; Vecchio, Antonio

    2017-01-01

    The recent discovery of the planetary system hosted by the ultracool dwarf star TRAPPIST-1 could open new paths for investigations of the planetary climates of Earth-sized exoplanets, their atmospheres, and their possible habitability. In this paper, we use a simple climate-vegetation energy-balance model to study the climate of the seven TRAPPIST-1 planets and the climate dependence on various factors: the global albedo, the fraction of vegetation that could cover their surfaces, and the different greenhouse conditions. The model allows us to investigate whether liquid water could be maintained on the planetary surfaces (i.e., by defining a “surface water zone (SWZ)”) in different planetary conditions, with or without the presence of a greenhouse effect. It is shown that planet TRAPPIST-1d seems to be the most stable from an Earth-like perspective, since it resides in the SWZ for a wide range of reasonable values of the model parameters. Moreover, according to the model, outer planets (f, g, and h) cannot host liquid water on their surfaces, even with Earth-like conditions, entering a snowball state. Although very simple, the model allows us to extract the main features of the TRAPPIST-1 planetary climates.

  9. Can planetary nebulae rotate

    International Nuclear Information System (INIS)

    Grinin, V.P.

    1982-01-01

    It is shown that the inclination of spectral lines observed in a number of planetary nebulae when the spectrograph slit is placed along the major axis, which is presently ascribed to nonuniform expansion of the shells, actually may be due to rotation of the nebulae about their minor axes, as Campbell and Moore have suggested in their reports. It is assumed that the rotation of the central star (or, if the core is a binary system, circular motions of gas along quasi-Keplerian orbits) serves as the source of the original rotation of a protoplanetary nebula. The mechanism providing for strengthening of the original rotation in the process of expansion of the shell is the tangential pressure of L/sub α/ radiation due to the anisotropic properties of the medium and radiation field. The dynamic effect produced by them is evidently greatest in the epoch when the optical depth of the nebula in the L/sub c/ continuum becomes on the order of unity in the course of its expansion

  10. Test models for estimating radiation balance in different scales for Jaboticabal, SP

    Directory of Open Access Journals (Sweden)

    Valquíria de Alencar Beserra

    2012-12-01

    Full Text Available The net radiation (Rn in agroecosystems is the amount of energy that is available in the environment to heating processes of living organisms, air and soil; perspiration of animals and plants; photosynthesis and water evaporation. The Rn defines the type of climate and weather conditions prevailing in a region affecting the availability and thermal water, the fundamental understanding of genotype-environment, which ultimately determine the productivity of the agricultural system. Rn usually is used in models of weather and climate studies. The sustainability and economic viability of zootechnical activity is dependent on the positive interaction between animal and environment. Environmental factors such as water, shading, thermal exchanges sensible heat (conduction, convection and radiation skin and latent heat losses (evaporation and transpiration, conditioned by Rn, must be managed to provide the best results. The present study was conducted to develop and test models for accurate and precise radiation balance on the scales daily, monthly and seasonal ten-day for Jaboticabal - SP, due to the importance of estimates of net radiation for agricultural activities. We used daily meteorological data from weather station located in Jaboticabal, SP (coordinates: 21 ° 14'05 "South, 48 ° 17'09" West, 615m altitude at Universidade Estadual Paulista "Júlio Mesquita Filho" - FCAV/UNESP in a situation of default grass "Bahiagrass" during the period 20/08/2005 to 20/01/2012. The data used were the maximum temperature (Tmax, minimum (Tmin and mean (TMED; maximum relative humidity (URMáx, minimum (URMín and average (URMéd precipitation (mm, average velocity (m/s, Qo, solar radiation (MJ m-2, sunshine (hour meter (MJ m², soil temperature at two depths (Tsoil2CM, Tsoil5CM and class A pan evaporation (TCA (mm. The measures taken by the balance radiometer were taken as a reference to test other models. The models tested were those reported by NORMAN et al

  11. The structure of the radiation balance on a sandy surface: case the Błędów desert, Silesian Upland

    Directory of Open Access Journals (Sweden)

    Caputa Zbigniew

    2016-06-01

    Full Text Available Comprehensive environmental studies taking under consideration the structure of the radiation balance during the vegetation growing seasons of 2001 and 2002 were carried out on the open sandy surface of the area called the Błędów ‘desert’ located on Silesian Upland. The research in each site covered the composition of plant species, their age and height, the condition of the substratum, the composition and structure of the soil and the meteorological conditions with elements of the radiation balance. The article presents some part of the research on meteorological elements and their impact on ecosystem. Special attention was devoted to radiation conditions on the open sandy surface in the context of the formation of BSC (biological soil crust. Having presumed that the values obtained on the grassy surface constituted 100%, the values of radiation reflection measured on the open sandy surface were 185% higher and the values of net longwave radiation were 105% higher in day time and 137% in night time. Values of net radiation of about 63% lower were observed on the sandy surface during a typical sunny summer day. It was found that a strong irradiation of the sandy surface (26 MJ·m–2d–1 creates extremely difficult conditions for the initiation of the process of ecosystem formation (including BSC or plant succession. The elements of the radiation balance, net radiation, albedo and temperature of the open sandy surface were represented quantitatively. The test surfaces were classified based on the value of the albedo: group I with low albedo values, up to 0.15 (spore-bearing plants on a dark surface, including BSC; group II with mean values of the albedo from 0.16 to 0.24 (spore-bearing plants and seed on a dark grey surface; and group III with high albedo values, above 0.25 (plants growing on bare or loose sands.

  12. Multidisciplinary approaches to radiation-balanced lasers (MARBLE): a MURI program by AFOSR (Conference Presentation)

    Science.gov (United States)

    Sheik-Bahae, Mansoor

    2017-02-01

    An overview of the diverse research activities under the newly funded MURI project by AFOSR will be presented. The main goal is to advance the science of radiation-balanced lasers, also known as athermal lasers, in order to mitigate the thermal degradation of the high-power laser beams. The MARBLE project involves researchers from four universities and spans research activities in rare-earth doped crystals and fibers to semiconductor disc lasers.

  13. PLANETARY EMBRYO BOW SHOCKS AS A MECHANISM FOR CHONDRULE FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Christopher R.; Boley, Aaron C. [Department of Physics and Astronomy University of British Columbia Vancouver, BC V6T 1Z1 (Canada); Morris, Melissa A. [Physics Department State University of New York at Cortland Cortland, NY 13045 (United States)

    2016-02-20

    We use radiation hydrodynamics with direct particle integration to explore the feasibility of chondrule formation in planetary embryo bow shocks. The calculations presented here are used to explore the consequences of a Mars-size planetary embryo traveling on a moderately excited orbit through the dusty, early environment of the solar system. The embryo’s eccentric orbit produces a range of supersonic relative velocities between the embryo and the circularly orbiting gas and dust, prompting the formation of bow shocks. Temporary atmospheres around these embryos, which can be created via volatile outgassing and gas capture from the surrounding nebula, can non-trivially affect thermal profiles of solids entering the shock. We explore the thermal environment of solids that traverse the bow shock at different impact radii, the effects that planetoid atmospheres have on shock morphologies, and the stripping efficiency of planetoidal atmospheres in the presence of high relative winds. Simulations are run using adiabatic and radiative conditions, with multiple treatments for the local opacities. Shock speeds of 5, 6, and 7 km s{sup −1} are explored. We find that a high-mass atmosphere and inefficient radiative conditions can produce peak temperatures and cooling rates that are consistent with the constraints set by chondrule furnace studies. For most conditions, the derived cooling rates are potentially too high to be consistent with chondrule formation.

  14. Review on the Role of Planetary Factors on Habitability.

    Science.gov (United States)

    Kereszturi, A; Noack, L

    2016-11-01

    In this work various factors on the habitability were considered, focusing on conditions irrespective of the central star's radiation, to see the role of specific planetary body related effects. These so called planetary factors were evaluated to identify those trans-domain issues where important information is missing but good chance exit to be filled by new knowledge that might be gained in the next decade(s). Among these strategic knowledge gaps, specific issues are listed, like occurrence of radioactive nucleides in star forming regions, models to estimate the existence of subsurface liquid water from bulk parameters plus evolutionary context of the given system, estimation on the existence of redox gradient depending on the environment type etc. These issues require substantial improvement of modelling and statistical handling of various cases, as "planetary environment types". Based on our current knowledge it is probable that subsurface habitability is at least as frequent, or more frequent than surface habitability. Unfortunately it is more difficult from observations to infer conditions for subsurface habitability, but specific argumentation might help with indirect ways, which might result in new methods to approach habitability in general.

  15. Radiation balances of melting snow covers at an open site in the Central Sierra Nevada, California

    International Nuclear Information System (INIS)

    Aguado, E.

    1985-01-01

    The radiation balances of melting snow packs for three seasons at an open site at the Central Sierra Snow Laboratory near Soda Springs, California were examined. The snow covers were examples of below-normal, near-normal and much-above-normal water equivalents. Two of the snow covers melted under generally clear skies in late spring while the other melted under cloudier conditions and at a time when less extraterrestrial radiation was available. Moreover, the snow covers were of very different densities, thereby allowing examination of a possible relationship between that characteristic and albedo. No such relationship was observed. Despite the dissimilarities in the conditions under which melt occurred, the disposition of solar radiation was similar for the three melt seasons. Albedos and their rates of decline through the melt season were similar for the three seasons. Absorbed solar radiation and a cloudiness index were useful predictors for daily net radiation, accounting for 71% of the total variance. (author)

  16. Observation-based estimation of aerosol-induced reduction of planetary boundary layer height

    Science.gov (United States)

    Zou, Jun; Sun, Jianning; Ding, Aijun; Wang, Minghuai; Guo, Weidong; Fu, Congbin

    2017-09-01

    Radiative aerosols are known to influence the surface energy budget and hence the evolution of the planetary boundary layer. In this study, we develop a method to estimate the aerosol-induced reduction in the planetary boundary layer height (PBLH) based on two years of ground-based measurements at a site, the Station for Observing Regional Processes of the Earth System (SORPES), at Nanjing University, China, and radiosonde data from the meteorological station of Nanjing. The observations show that increased aerosol loads lead to a mean decrease of 67.1 W m-2 for downward shortwave radiation (DSR) and a mean increase of 19.2 W m-2 for downward longwave radiation (DLR), as well as a mean decrease of 9.6 Wm-2 for the surface sensible heat flux (SHF) in the daytime. The relative variations of DSR, DLR and SHF are shown as a function of the increment of column mass concentration of particulate matter (PM2.5). High aerosol loading can significantly increase the atmospheric stability in the planetary boundary layer during both daytime and nighttime. Based on the statistical relationship between SHF and PM2.5 column mass concentrations, the SHF under clean atmospheric conditions (same as the background days) is derived. In this case, the derived SHF, together with observed SHF, are then used to estimate changes in the PBLH related to aerosols. Our results suggest that the PBLH decreases more rapidly with increasing aerosol loading at high aerosol loading. When the daytime mean column mass concentration of PM2.5 reaches 200 mg m-2, the decrease in the PBLH at 1600 LST (local standard time) is about 450 m.

  17. The Fifteen-Year Attitude History of the Wide Field Planetary Camera 2 Radiator and Collection Efficiencies for Micrometeoroids and Orbital Debris

    Science.gov (United States)

    Anz-Meador, Phillip D.; Liou, Jer-Chyi; Cooke, William J.; Koehler, H.

    2010-01-01

    An examination of the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC-2) radiator assembly was conducted at NASA Goddard Space Flight Center (GSFC) during the summer of 2009. Immediately apparent was a distinct biasing of the largest 45 impact features towards one side of the radiator, in contrast to an approximately uniform distribution of smaller impacts. Such a distribution may be a consequence of the HST s attitude history and pointing requirements for the cold radiator, or of environmental effects, such as an anisotropic distribution of the responsible population in that size regime. Understanding the size-dependent spatial distribution of impact features is essential to the general analysis of these features. We have obtained from GSFC a 15 minute temporal resolution record of the state vector (Earth Centered Inertial position and velocity) and HST attitude, consisting of the orientation of the velocity and HST-sun vectors in HST body coordinates. This paper reviews the actual state vector and attitude history of the radiator in the context of the randomly tumbling plate assumption and assesses the statistical likelihood (or collection efficiency) of the radiator for the micrometeoroid and orbital debris environments. The NASA Marshall Space Flight Center s Meteoroid Environment Model is used to assess the micrometeoroid component. The NASA Orbital Debris Engineering Model (ORDEM) is used to model the orbital debris component. Modeling results are compared with observations of the impact feature spatial distribution, and the relative contribution of each environmental component are examined in detail.

  18. The Solar Connections Observatory for Planetary Environments

    Science.gov (United States)

    Oliversen, Ronald J.; Harris, Walter M.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    The NASA Sun-Earth Connection theme roadmap calls for comparative study of how the planets, comets, and local interstellar medium (LISM) interact with the Sun and respond to solar variability. Through such a study we advance our understanding of basic physical plasma and gas dynamic processes, thus increasing our predictive capabilities for the terrestrial, planetary, and interplanetary environments where future remote and human exploration will occur. Because the other planets have lacked study initiatives comparable to the terrestrial ITM, LWS, and EOS programs, our understanding of the upper atmospheres and near space environments on these worlds is far less detailed than our knowledge of the Earth. To close this gap we propose a mission to study {\\it all) of the solar interacting bodies in our planetary system out to the heliopause with a single remote sensing space observatory, the Solar Connections Observatory for Planetary Environments (SCOPE). SCOPE consists of a binocular EUV/FUV telescope operating from a remote, driftaway orbit that provides sub-arcsecond imaging and broadband medium resolution spectro-imaging over the 55-290 nm bandpass, and high (R>10$^{5}$ resolution H Ly-$\\alpha$ emission line profile measurements of small scale planetary and wide field diffuse solar system structures. A key to the SCOPE approach is to include Earth as a primary science target. From its remote vantage point SCOPE will be able to observe auroral emission to and beyond the rotational pole. The other planets and comets will be monitored in long duration campaigns centered when possible on solar opposition when interleaved terrestrial-planet observations can be used to directly compare the response of both worlds to the same solar wind stream and UV radiation field. Using a combination of observations and MHD models, SCOPE will isolate the different controlling parameters in each planet system and gain insight into the underlying physical processes that define the

  19. Planetary Defense

    Science.gov (United States)

    2016-05-01

    4 Abstract Planetary defense against asteroids should be a major concern for every government in the world . Millions of asteroids and...helps make Planetary Defense viable because defending the Earth against asteroids benefits from all the above technologies. So if our planet security...information about their physical characteristics so we can employ the right strategies. It is a crucial difference if asteroids are made up of metal

  20. Solar planetary systems stardust to terrestrial and extraterrestrial planetary sciences

    CERN Document Server

    Bhattacharya, Asit B

    2017-01-01

    The authors have put forth great efforts in gathering present day knowledge about different objects within our solar system and universe. This book features the most current information on the subject with information acquired from noted scientists in this area. The main objective is to convey the importance of the subject and provide detailed information on the physical makeup of our planetary system and technologies used for research. Information on educational projects has also been included in the Radio Astronomy chapters.This information is a real plus for students and educators considering a career in Planetary Science or for increasing their knowledge about our planetary system

  1. Use of MODIS Images to Quantify the Radiation and Energy Balances in the Brazilian Pantanal

    Directory of Open Access Journals (Sweden)

    Antônio H. de C. Teixeira

    2015-11-01

    Full Text Available MODIS images during the year 2012 were used for modelling of the radiation and energy balance components with the application of the SAFER algorithm (Simple Algorithm for Evapotranspiration Retrieving in the Brazilian Pantanal area. Pixels from the main sub-regions of Barão de Melgaço (BR, Paiaguás (PA and Nhecolândia (NH were extracted in order to process microclimatic comparisons. In general, the net radiation (Rn relied much more on the global solar radiation (RG levels than on water conditions and ecosystem types, in accordance with the low Rn standard deviation values. The fraction of the available energy used as latent heat flux (λE were, on average, 65, 50 and 49% for the BR, PA and NH sub-regions, respectively. Horizontal heat advection, identified by the negative values of sensible heat flux (H, made several pixels with λE values higher than those for Rn in the middle of the year. Taking the evaporative fraction (Ef as a surface moisture indicator, the Tree-Lined Savanna (TLS was considered the moister ecosystem class, with 58% of the available energy being used as λE, while the driest one was the modified ecosystem Anthropogenic Changes (AC, presenting a λE/Rn fraction of 0.46. According to the spatial and temporal consistencies, and after comparisons with other previous point and large-scale studies, the SAFER algorithm proved to have sensibility to quantify and compare the large-scale radiation and energy balance components in the different ecosystems of the Brazilian Pantanal. The algorithm is useful for monitoring the energy exchange dynamics among the different terrestrial and aquatic ecosystem types throughout the seasons of the year.

  2. New and misclassified planetary nebulae

    International Nuclear Information System (INIS)

    Kohoutek, L.

    1978-01-01

    Since the 'Catalogue of Galactic Planetary Nebulae' 226 new objects have been classified as planetary nebulae. They are summarized in the form of designations, names, coordinates and the references to the discovery. Further 9 new objects have been added and called 'proto-planetary nebulae', but their status is still uncertain. Only 34 objects have been included in the present list of misclassified planetary nebulae although the number of doubtful cases is much larger. (Auth.)

  3. Ionizing radiation and life.

    Science.gov (United States)

    Dartnell, Lewis R

    2011-01-01

    Ionizing radiation is a ubiquitous feature of the Cosmos, from exogenous cosmic rays (CR) to the intrinsic mineral radioactivity of a habitable world, and its influences on the emergence and persistence of life are wide-ranging and profound. Much attention has already been focused on the deleterious effects of ionizing radiation on organisms and the complex molecules of life, but ionizing radiation also performs many crucial functions in the generation of habitable planetary environments and the origins of life. This review surveys the role of CR and mineral radioactivity in star formation, generation of biogenic elements, and the synthesis of organic molecules and driving of prebiotic chemistry. Another major theme is the multiple layers of shielding of planetary surfaces from the flux of cosmic radiation and the various effects on a biosphere of violent but rare astrophysical events such as supernovae and gamma-ray bursts. The influences of CR can also be duplicitous, such as limiting the survival of surface life on Mars while potentially supporting a subsurface biosphere in the ocean of Europa. This review highlights the common thread that ionizing radiation forms between the disparate component disciplines of astrobiology. © Mary Ann Liebert, Inc.

  4. Can quantum coherent solar cells break detailed balance?

    International Nuclear Information System (INIS)

    Kirk, Alexander P.

    2015-01-01

    Carefully engineered coherent quantum states have been proposed as a design attribute that is hypothesized to enable solar photovoltaic cells to break the detailed balance (or radiative) limit of power conversion efficiency by possibly causing radiative recombination to be suppressed. However, in full compliance with the principles of statistical mechanics and the laws of thermodynamics, specially prepared coherent quantum states do not allow a solar photovoltaic cell—a quantum threshold energy conversion device—to exceed the detailed balance limit of power conversion efficiency. At the condition given by steady-state open circuit operation with zero nonradiative recombination, the photon absorption rate (or carrier photogeneration rate) must balance the photon emission rate (or carrier radiative recombination rate) thus ensuring that detailed balance prevails. Quantum state transitions, entropy-generating hot carrier relaxation, and photon absorption and emission rate balancing are employed holistically and self-consistently along with calculations of current density, voltage, and power conversion efficiency to explain why detailed balance may not be violated in solar photovoltaic cells

  5. From red giants to planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1982-01-01

    The transition from red giants to planetary nebulae is studied by comparing the spectral characteristics of red giant envelopes and planetary nebulae. Observational and theoretical evidence both suggest that remnants of red giant envelopes may still be present in planetary nebula systems and should have significant effects on their formation. The dynamical effects of the interaction of stellar winds from central stars of planetary nebulae with the remnant red giant envelopes are evaluated and the mechanism found to be capable of producing the observed masses and momenta of planetary nebulae. The observed mass-radii relation of planetary nebulae may also be best explained by the interacting winds model. The possibility that red giant mass loss, and therefore the production of planetary nebulae, is different between Population I and II systems is also discussed

  6. The ExtraSolar Planetary Imaging Coronagraph

    Science.gov (United States)

    Clampin, M.; Lyon, R.

    2010-10-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a 1.65-m telescope employing a visible nulling coronagraph (VNC) to deliver high-contrast images of extrasolar system architectures. EPIC will survey the architectures of exosolar systems, and investigate the physical nature of planets in these solar systems. EPIC will employ a Visible Nulling Coronagraph (VNC), featuring an inner working angle of ≤2λ/D, and offers the ideal balance between performance and feasibility of implementation, while not sacrificing science return. The VNC does not demand unrealistic thermal stability from its telescope optics, achieving its primary mirror surface figure requires no new technology, and pointing stability is within state of the art. The EPIC mission will be launched into a drift-away orbit with a five-year mission lifetime.

  7. Planetary Radio Interferometry and Doppler Experiment (PRIDE) for Planetary Atmospheric Studies

    Science.gov (United States)

    Bocanegra Bahamon, Tatiana; Cimo, Giuseppe; Duev, Dmitry; Gurvits, Leonid; Molera Calves, Guifre; Pogrebenko, Sergei

    2015-04-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that allows the determination of the radial velocity and lateral coordinates of planetary spacecraft with very high accuracy (Duev, 2012). The setup of the experiment consists of several ground stations from the European VLBI Network (EVN) located around the globe, which simultaneously perform Doppler tracking of a spacecraft carrier radio signal, and are subsequently processed in a VLBI-style in phase referencing mode. Because of the accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of planetary research, among which planetary atmospheric studies, gravimetry and ultra-precise celestial mechanics of planetary systems. In the study at hand the application of this technique for planetary atmospheric investigations is demonstrated. As a test case, radio occultation experiments were conducted with PRIDE having as target ESA's Venus Express, during different observing sessions with multiple ground stations in April 2012 and March 2014. Once each of the stations conducts the observation, the raw data is delivered to the correlation center at the Joint Institute for VLBI in Europe (JIVE) located in the Netherlands. The signals are processed with a high spectral resolution and phase detection software package from which Doppler observables of each station are derived. Subsequently the Doppler corrected signals are correlated to derive the VLBI observables. These two sets of observables are used for precise orbit determination. The reconstructed orbit along with the Doppler observables are used as input for the radio occultation processing software, which consists of mainly two modules, the geometrical optics module and the ray tracing inversion module, from which vertical density profiles, and subsequently, temperature and pressure profiles of Venus

  8. Trends in Planetary Data Analysis. Executive summary of the Planetary Data Workshop

    Science.gov (United States)

    Evans, N.

    1984-09-01

    Planetary data include non-imaging remote sensing data, which includes spectrometric, radiometric, and polarimetric remote sensing observations. Also included are in-situ, radio/radar data, and Earth based observation. Also discussed is development of a planetary data system. A catalog to identify observations will be the initial entry point for all levels of users into the data system. There are seven distinct data support services: encyclopedia, data index, data inventory, browse, search, sample, and acquire. Data systems for planetary science users must provide access to data, process, store, and display data. Two standards will be incorporated into the planetary data system: Standard communications protocol and Standard format data unit. The data system configuration must combine a distributed system with those of a centralized system. Fiscal constraints have made prioritization important. Activities include saving previous mission data, planning/cost analysis, and publishing of proceedings.

  9. Planetary Data System (PDS)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Planetary Data System (PDS) is an archive of data products from NASA planetary missions, which is sponsored by NASA's Science Mission Directorate. We actively...

  10. Planetary Science Training for NASA's Astronauts: Preparing for Future Human Planetary Exploration

    Science.gov (United States)

    Bleacher, J. E.; Evans, C. A.; Graff, T. G.; Young, K. E.; Zeigler, R.

    2017-02-01

    Astronauts selected in 2017 and in future years will carry out in situ planetary science research during exploration of the solar system. Training to enable this goal is underway and is flexible to accommodate an evolving planetary science vision.

  11. Planetary Geologic Mapping Handbook - 2009

    Science.gov (United States)

    Tanaka, K. L.; Skinner, J. A.; Hare, T. M.

    2009-01-01

    Geologic maps present, in an historical context, fundamental syntheses of interpretations of the materials, landforms, structures, and processes that characterize planetary surfaces and shallow subsurfaces (e.g., Varnes, 1974). Such maps also provide a contextual framework for summarizing and evaluating thematic research for a given region or body. In planetary exploration, for example, geologic maps are used for specialized investigations such as targeting regions of interest for data collection and for characterizing sites for landed missions. Whereas most modern terrestrial geologic maps are constructed from regional views provided by remote sensing data and supplemented in detail by field-based observations and measurements, planetary maps have been largely based on analyses of orbital photography. For planetary bodies in particular, geologic maps commonly represent a snapshot of a surface, because they are based on available information at a time when new data are still being acquired. Thus the field of planetary geologic mapping has been evolving rapidly to embrace the use of new data and modern technology and to accommodate the growing needs of planetary exploration. Planetary geologic maps have been published by the U.S. Geological Survey (USGS) since 1962 (Hackman, 1962). Over this time, numerous maps of several planetary bodies have been prepared at a variety of scales and projections using the best available image and topographic bases. Early geologic map bases commonly consisted of hand-mosaicked photographs or airbrushed shaded-relief views and geologic linework was manually drafted using mylar bases and ink drafting pens. Map publishing required a tedious process of scribing, color peel-coat preparation, typesetting, and photo-laboratory work. Beginning in the 1990s, inexpensive computing, display capability and user-friendly illustration software allowed maps to be drawn using digital tools rather than pen and ink, and mylar bases became obsolete

  12. Spectral and diurnal variations in clear sky planetary albedo

    Science.gov (United States)

    Briegleb, B.; Ramanathan, V.

    1982-01-01

    Spectral and diurnal variations in the clear sky planetary albedo of the earth are calculated using a radiative transfer model to obtain January and July values for a 5 deg x 5 deg global grid. The model employs observed climatological values of temperatures, humidities, snow and sea-ice cover. The diurnal cycle of clear sky albedo is calculated in the following intervals: 0.2-0.5, 0.5-0.7, and 0.7-4 microns. Observed ozone distribution is specified as a function of latitude and season. The 0.2-0.5 micron spectral albedo is 10-20% higher than the total albedo for all latitudes because of Rayleigh scattering; the 0.5-0.7 micron albedo differs from the total albedo by 1-2% for most latitudes, while the 0.7-4 micron albedo is 5-10% lower than the total because of strong atmospheric absorption. Planetary albedo decreases from morning to local noon, with diurnal variations being particularly strong over water.

  13. Fire-induced albedo change and surface radiative forcing in sub-Saharan Africa savanna ecosystems: Implications for the energy balance

    Science.gov (United States)

    Dintwe, Kebonye; Okin, Gregory S.; Xue, Yongkang

    2017-06-01

    Surface albedo is a critical parameter that controls surface energy balance. In dryland ecosystems, fires play a significant role in decreasing surface albedo, resulting in positive radiative forcing. Here we investigate the long-term effect of fire on surface albedo. We devised a method to calculate short-, medium-, and long-term effect of fire-induced radiative forcing and their relative effects on energy balance. We used Moderate Resolution Imaging Spectroradiometer (MODIS) data in our analysis, covering different vegetation classes in sub-Saharan Africa (SSA). Our analysis indicated that mean short-term fire-induced albedo change in SSA was -0.022, -0.035, and -0.041 for savannas, shrubland, and grasslands, respectively. At regional scale, mean fire-induced albedo change in savannas was -0.018 and -0.024 for northern sub-Saharan of Africa and the southern hemisphere Africa, respectively. The short-term mean fire-induced radiative forcing in burned areas in sub-Saharan Africa (SSA) was 5.41 W m-2, which contributed continental and global radiative forcings of 0.25 and 0.058 W m-2, respectively. The impact of fire in surface albedo has long-lasting effects that varies with vegetation type. The long-term energetic effects of fire-induced albedo change and associated radiative forcing were, on average, more than 19 times greater across SSA than the short-term effects, suggesting that fires exerted far more radiative forcing than previously thought. Taking into account the actual duration of fire's effect on surface albedo, we conclude that the contribution of SSA fires, globally and throughout the year, is 0.12 W m-2. These findings provide crucial information on possible impact of fire on regional climate variability.

  14. Preparing Planetary Scientists to Engage Audiences

    Science.gov (United States)

    Shupla, C. B.; Shaner, A. J.; Hackler, A. S.

    2017-12-01

    While some planetary scientists have extensive experience sharing their science with audiences, many can benefit from guidance on giving presentations or conducting activities for students. The Lunar and Planetary Institute (LPI) provides resources and trainings to support planetary scientists in their communication efforts. Trainings have included sessions for students and early career scientists at conferences (providing opportunities for them to practice their delivery and receive feedback for their poster and oral presentations), as well as separate communication workshops on how to engage various audiences. LPI has similarly begun coaching planetary scientists to help them prepare their public presentations. LPI is also helping to connect different audiences and their requests for speakers to planetary scientists. Scientists have been key contributors in developing and conducting activities in LPI education and public events. LPI is currently working with scientists to identify and redesign short planetary science activities for scientists to use with different audiences. The activities will be tied to fundamental planetary science concepts, with basic materials and simple modifications to engage different ages and audience size and background. Input from the planetary science community on these efforts is welcome. Current results and resources, as well as future opportunities will be shared.

  15. Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin

    2014-12-01

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.

  16. The direct effect of aerosols on solar radiation over the broader Mediterranean basin

    Directory of Open Access Journals (Sweden)

    C. D. Papadimas

    2012-08-01

    Full Text Available For the first time, the direct radiative effect (DRE of aerosols on solar radiation is computed over the entire Mediterranean basin, one of the most climatically sensitive world regions, using a deterministic spectral radiation transfer model (RTM. The DRE effects on the outgoing shortwave radiation at the top of atmosphere (TOA, DRETOA, on the absorption of solar radiation in the atmospheric column, DREatm, and on the downward and absorbed surface solar radiation (SSR, DREsurf and DREnetsurf, respectively, are computed separately. The model uses input data for the period 2000–2007 for various surface and atmospheric parameters, taken from satellite (International Satellite Cloud Climatology Project, ISCCP-D2, Global Reanalysis projects (National Centers for Environmental Prediction – National Center for Atmospheric Research, NCEP/NCAR, and other global databases. The spectral aerosol optical properties (aerosol optical depth, AOD, asymmetry parameter, gaer and single scattering albedo, ωaer, are taken from the MODerate resolution Imaging Spectroradiometer (MODIS of NASA (National Aeronautics and Space Administration and they are supplemented by the Global Aerosol Data Set (GADS. The model SSR fluxes have been successfully validated against measurements from 80 surface stations of the Global Energy Balance Archive (GEBA covering the period 2000–2007.

    A planetary cooling is found above the Mediterranean on an annual basis (regional mean DRETOA = −2.4 W m−2. Although a planetary cooling is found over most of the region, of up to −7 W m−2, large positive DRETOA values (up to +25 W m−2 are found over North Africa, indicating a strong planetary warming, and a weaker warming over the Alps (+0.5 W m−2. Aerosols are found to increase the absorption of solar radiation in the atmospheric

  17. Experiments on the Scaling of Ionization Balance vs. Electron and Radiation Temperature in Non-LTE Gold Plasmas

    International Nuclear Information System (INIS)

    Heeter, R.F.; Hansen, S.B.; Beiersdorfer, P.; Foord, M.E.; Fournier, K.B.; Froula, D.H.; Mackinnon, A.J.; May, M.J.; Schneider, M.B.; Young, B.K.F.

    2004-01-01

    Understanding and predicting the behavior of high-Z non-LTE plasmas is important for developing indirect-drive inertial confinement fusion. Extending earlier work from the Nova laser, we present results from experiments using the Omega laser to study the ionization balance of gold as a function of electron and radiation temperature. In these experiments, gold samples embedded in Be disks expand under direct laser heating to ne ≅ 1021cm-3, with Te varying from 0.8 to 2.5 keV. An additional finite radiation field with effective temperature Tr up to 150 eV is provided by placing the gold Be disks inside truncated 1.2 mm diameter tungsten-coated cylindrical hohlraums with full laser entrance holes. Densities are measured by imaging of plasma expansion. Electron temperatures are diagnosed with either 2ω or 4ω Thomson scattering, and also K-shell spectroscopy of KCl tracers co-mixed with the gold. Hohlraum flux and effective radiation temperature are measured using an absolutely-calibrated multichannel filtered diode array. Spectroscopic measurements of the M-shell gold emission in the 2.9-4 keV spectral range provide ionization balance and charge state distribution information. The spectra show strong variation with Te, strong variation with the applied Tr, at Te below 1.6 keV, and relatively little variation with Tr at higher Te (upwards of 2 keV). We summarize our most recent spectral analyses and discuss emerging and outstanding issues

  18. Energy Balance, Climate, and Life - Work of M. Budyko

    Science.gov (United States)

    Cahalan, Robert F.

    2004-01-01

    This talk will review the work of Mikhail I. Budyko, author of "Climate and Life" and many other works, who died recently at age 81, in St Petersburg, Russia. He directed the Division for Climate Change Research at the State Hydrological Institute. We will explore Budyko's work in clarifying the role of energy balance in determining planetary climate, and the role of climate in regulating Earth s biosphere.

  19. Energy Balance, Climate, and Life \\-- Work of M. Budyko

    Science.gov (United States)

    Cahalan, R. F.

    2003-12-01

    This talk will review the work of Mikhail I. Budyko, author of "Climate and Life" and many other works, who died recently at the age of 81 in St. Petersburg, Russia. He directed the Division for Climate Change Research at the State Hydrological Institute. We will explore Budyko's work in clarifying the role of energy balance in determining planetary climate, and the role of climate in regulating Earth's biosphere.

  20. Planetary Data Archiving Plan at JAXA

    Science.gov (United States)

    Shinohara, Iku; Kasaba, Yasumasa; Yamamoto, Yukio; Abe, Masanao; Okada, Tatsuaki; Imamura, Takeshi; Sobue, Shinichi; Takashima, Takeshi; Terazono, Jun-Ya

    After the successful rendezvous of Hayabusa with the small-body planet Itokawa, and the successful launch of Kaguya to the moon, Japanese planetary community has gotten their own and full-scale data. However, at this moment, these datasets are only available from the data sites managed by each mission team. The databases are individually constructed in the different formats, and the user interface of these data sites is not compatible with foreign databases. To improve the usability of the planetary archives at JAXA and to enable the international data exchange smooth, we are investigating to make a new planetary database. Within a coming decade, Japan will have fruitful datasets in the planetary science field, Venus (Planet-C), Mercury (BepiColombo), and several missions in planning phase (small-bodies). In order to strongly assist the international scientific collaboration using these mission archive data, the planned planetary data archive at JAXA should be managed in an unified manner and the database should be constructed in the international planetary database standard style. In this presentation, we will show the current status and future plans of the planetary data archiving at JAXA.

  1. Application of the modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas in complex environment

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    In this paper, application of a modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small antennas is presented. It is shown that the limitations on the cavity dimension can be overcome and thus measurement in a large cavity is possible. The cavity loss...... is investigated, and a modified radiation efficiency formula that includes the cavity loss is introduced. Moreover, a modification of the technique is proposed that involves the antenna working complex environment inside the Wheeler Cap and thus makes possible measurement of an antenna close to a hand or head...

  2. The Planetary Data System— Archiving Planetary Data for the use of the Planetary Science Community

    Science.gov (United States)

    Morgan, Thomas H.; McLaughlin, Stephanie A.; Grayzeck, Edwin J.; Vilas, Faith; Knopf, William P.; Crichton, Daniel J.

    2014-11-01

    NASA’s Planetary Data System (PDS) archives, curates, and distributes digital data from NASA’s planetary missions. PDS provides the planetary science community convenient online access to data from NASA’s missions so that they can continue to mine these rich data sets for new discoveries. The PDS is a federated system consisting of nodes for specific discipline areas ranging from planetary geology to space physics. Our federation includes an engineering node that provides systems engineering support to the entire PDS.In order to adequately capture complete mission data sets containing not only raw and reduced instrument data, but also calibration and documentation and geometry data required to interpret and use these data sets both singly and together (data from multiple instruments, or from multiple missions), PDS personnel work with NASA missions from the initial AO through the end of mission to define, organize, and document the data. This process includes peer-review of data sets by members of the science community to ensure that the data sets are scientifically useful, effectively organized, and well documented. PDS makes the data in PDS easily searchable so that members of the planetary community can both query the archive to find data relevant to specific scientific investigations and easily retrieve the data for analysis. To ensure long-term preservation of data and to make data sets more easily searchable with the new capabilities in Information Technology now available (and as existing technologies become obsolete), the PDS (together with the COSPAR sponsored IPDA) developed and deployed a new data archiving system known as PDS4, released in 2013. The LADEE, MAVEN, OSIRIS REx, InSight, and Mars2020 missions are using PDS4. ESA has adopted PDS4 for the upcoming BepiColumbo mission. The PDS is actively migrating existing data records into PDS4 and developing tools to aid data providers and users. The PDS is also incorporating challenge

  3. Planetary Geologic Mapping Handbook - 2010. Appendix

    Science.gov (United States)

    Tanaka, K. L.; Skinner, J. A., Jr.; Hare, T. M.

    2010-01-01

    Geologic maps present, in an historical context, fundamental syntheses of interpretations of the materials, landforms, structures, and processes that characterize planetary surfaces and shallow subsurfaces. Such maps also provide a contextual framework for summarizing and evaluating thematic research for a given region or body. In planetary exploration, for example, geologic maps are used for specialized investigations such as targeting regions of interest for data collection and for characterizing sites for landed missions. Whereas most modern terrestrial geologic maps are constructed from regional views provided by remote sensing data and supplemented in detail by field-based observations and measurements, planetary maps have been largely based on analyses of orbital photography. For planetary bodies in particular, geologic maps commonly represent a snapshot of a surface, because they are based on available information at a time when new data are still being acquired. Thus the field of planetary geologic mapping has been evolving rapidly to embrace the use of new data and modern technology and to accommodate the growing needs of planetary exploration. Planetary geologic maps have been published by the U.S. Geological Survey (USGS) since 1962. Over this time, numerous maps of several planetary bodies have been prepared at a variety of scales and projections using the best available image and topographic bases. Early geologic map bases commonly consisted of hand-mosaicked photographs or airbrushed shaded-relief views and geologic linework was manually drafted using mylar bases and ink drafting pens. Map publishing required a tedious process of scribing, color peel-coat preparation, typesetting, and photo-laboratory work. Beginning in the 1990s, inexpensive computing, display capability and user-friendly illustration software allowed maps to be drawn using digital tools rather than pen and ink, and mylar bases became obsolete. Terrestrial geologic maps published by

  4. Considerations in the Design of Future Planetary Laser Altimeters

    Science.gov (United States)

    Smith, D. E.; Neumann, G. A.; Mazarico, E.; Zuber, M. T.; Sun, X.

    2017-12-01

    Planetary laser altimeters have generally been designed to provide high accuracy measurements of the nadir range to an uncooperative surface for deriving the shape of the target body, and sometimes specifically for identifying and characterizing potential landing sites. However, experience has shown that in addition to the range measurement, other valuable observations can be acquired, including surface reflectance and surface roughness, despite not being given high priority in the original altimeter design or even anticipated. After nearly 2 decades of planetary laser altimeter design, the requirements are evolving and additional capabilities are becoming equally important. The target bodies, once the terrestrial planets, are now equally asteroids and moons that in many cases do not permit simple orbital operations due to their small mass, radiation issues, or spacecraft fuel limitations. In addition, for a number of reasons, it has become necessary to perform shape determination from a much greater range, even thousands of kilometers, and thus ranging is becoming as important as nadir altimetry. Reflectance measurements have also proved important for assessing the presence of ice, water or CO2, and laser pulse spreading informed knowledge of surface roughness; all indicating a need for improved instrument capability. Recently, the need to obtain accurate range measurement to laser reflectors on landers or on a planetary surface is presenting new science opportunities but for which current designs are far from optimal. These changes to classic laser altimetry have consequences for many instrument functions and capabilities, including beam divergence, laser power, number of beams and detectors, pixelation, energy measurements, pointing stability, polarization, laser wavelengths, and laser pulse rate dependent range. We will discuss how a new consideration of these trades will help make lidars key instruments to execute innovative science in future planetary

  5. Influences of deforestation on radiation and heat balances in tropical peat swamp forest in Thailand

    International Nuclear Information System (INIS)

    Suzuki, S.; Ishida, T.; Nagano, T.; Matsukawa, S.

    1997-01-01

    The difference of radiation and heat balances between a natural peat swamp forest and a deforested secondary forest has been investigated in Narathiwat Province, Thailand. Micrometeorological measurements were conducted continuously on observation towers 38 m and 4 m in heights in the primary forest and the secondary forest respectively. Results show that the deforestation of peat swamp forest leads to an increase in the sensible heat flux in the secondary forest. The yearly average ratio of the sensible heat flux to the net radiation was 20.9% in the peat swamp forest, and 33.2% in the secondary forest from Aug. 1995 to Jul. 1996. A ratio more than 40% was observed only in the dry season in the secondary forest. The change in sensible heat flux seemed to be influenced by the change in ground water levels. (author)

  6. Spatiotemporal Variability of Earth's Radiation Balance Components from Russian Radiometer IKOR-M

    Science.gov (United States)

    Cherviakov, M.

    2016-12-01

    The radiometer IKOR-M was created in National Research Saratov State University for satellite monitoring of the outgoing reflected short-wave radiation, which is one of the components of Earth's radiation budget. Such information can be used in different models of long-term weather forecasts, in researches of climate change trends and in calculation of absorbed solar radiation values and albedo of the Earth-atmosphere system. The IKOR-M product archive is available online at all times. A searchable catalogue of data products is continually updated and users may search and download data products via the Earth radiation balance components research laboratory website as soon as they become available. Two series of measurements from two different IKOR-M are available. The first radiometer had worked from October 2009 to August 2014 and second - from August 2014 to the present. Therefore, there is a period when both radiometers work at the same time. Top-of-atmosphere fluxes deduced from the "Meteor-M" No 1 measurement in August, 2014 show very good agreement with the fluxes determined from "Meteor-M" No 2. The scale relationship of the IKOR-M radiometers on "Meteor - M" No 1 and No 2 satellites found by comparing of the global distribution maps for monthly averaged albedo values. The seasonal and interannual variations of OSR, albedo and ASR were discussed. The variations between SW radiation budget components seem to be within observational uncertainty and natural variability governed by cloudiness, water vapor and aerosol variations. It was assessed spatial and temporal variations of albedo and the absorbed solar radiation over different regions. Latitudinal distributions of albedo and ASR were estimated in more detail. Meridional cross sections over oceans and land were used separately for this estimation. It was shown that the albedo and ASR data received from the radiometer IKOR-M can be used to detect El Nino in the Pacific Ocean. The reported study was funded by

  7. Kinematics of galactic planetary nebulae

    International Nuclear Information System (INIS)

    Kiosa, M.I.; Khromov, G.S.

    1979-01-01

    The classical method of determining the components of the solar motion relative to the centroid of the system of planetary nebulae with known radial velocities is investigated. It is shown that this method is insensitive to random errors in the radial velocities and that low accuracy in determining the coordinates of the solar apex and motion results from the insufficient number of planetaries with measured radial velocities. The planetary nebulae are found not to satisfy well the law of differential galactic rotation with circular orbits. This is attributed to the elongation of their galactic orbits. A method for obtaining the statistical parallax of planetary nebulae is considered, and the parallax calculated from the tau components of their proper motion is shown to be the most reliable

  8. Operational Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    André, Nicolas; Grande, Manuel

    2017-04-01

    Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI, http://www.europlanet-2020-ri.eu) includes an entirely new Virtual Access Service, "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. PSWS will provide at the end of 2017 12 services distributed over 4 different service domains - 1) Prediction, 2) Detection, 3) Modelling, 4) Alerts. These services include 1.1) A 1D MHD solar wind prediction tool, 1.2) Extensions of a Propagation Tool, 1.3) A meteor showers prediction tool, 1.4) A cometary tail crossing prediction tool, 2.1) Detection of lunar impacts, 2.2) Detection of giant planet fireballs, 2.3) Detection of cometary tail events, 3.1) A Transplanet model of magnetosphere-ionosphere coupling, 3.2) A model of the Mars radiation environment, 3.3.) A model of giant planet magnetodisc, 3.4) A model of Jupiter's thermosphere, 4) A VO-event based alert system. We will detail in the present paper some of these services with a particular emphasis on those already operational at the time of the presentation (1.1, 1.2, 1.3, 2.2, 3.1, 4). The proposed Planetary Space Weather Services will be accessible to the research community, amateur astronomers as well as to industrial partners planning for space missions dedicated in particular to the following key planetary environments: Mars, in support of ESA's ExoMars missions; comets, building on the success of the ESA Rosetta mission; and outer planets, in preparation for the ESA JUpiter ICy moon Explorer (JUICE). These services will also be augmented by the future Solar Orbiter and BepiColombo observations. This new facility will not only have an impact on planetary space missions but will also allow the hardness of spacecraft and their components to be evaluated under variety of known conditions, particularly radiation conditions, extending

  9. Radiation entropy influx as a measure of planetary dissipative processes

    International Nuclear Information System (INIS)

    Izakov, M.N.

    1989-01-01

    Dissipative processes including high flows of matter and energy occur at the planets. Radiation negentropy influx, resulting from difference of entropy fluxes of incoming solar and outgoing thermal radiation of the planet, is a measure of all these processes. Large share of radiation negentropy influx is spent in the vertical thermal fluxes which keep the planet temperature conditions. Next share of radiation negentropy consumption at the Earth is water evaporation. It's rest part is used for the dynamics, which is explained by the efficiency insignificant amount of heat engine, which generates movements in the atmosphere and ocean. Essentially higher share of radiation negentropy influx, than at the Earth, is spent at the Venus, where there are practically no water

  10. Improving accessibility and discovery of ESA planetary data through the new planetary science archive

    Science.gov (United States)

    Macfarlane, A. J.; Docasal, R.; Rios, C.; Barbarisi, I.; Saiz, J.; Vallejo, F.; Besse, S.; Arviset, C.; Barthelemy, M.; De Marchi, G.; Fraga, D.; Grotheer, E.; Heather, D.; Lim, T.; Martinez, S.; Vallat, C.

    2018-01-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific data sets through various interfaces at http://psa.esa.int. Mostly driven by the evolution of the PDS standards which all new ESA planetary missions shall follow and the need to update the interfaces to the archive, the PSA has undergone an important re-engineering. In order to maximise the scientific exploitation of ESA's planetary data holdings, significant improvements have been made by utilising the latest technologies and implementing widely recognised open standards. To facilitate users in handling and visualising the many products stored in the archive which have spatial data associated, the new PSA supports Geographical Information Systems (GIS) by implementing the standards approved by the Open Geospatial Consortium (OGC). The modernised PSA also attempts to increase interoperability with the international community by implementing recognised planetary science specific protocols such as the PDAP (Planetary Data Access Protocol) and EPN-TAP (EuroPlanet-Table Access Protocol). In this paper we describe some of the methods by which the archive may be accessed and present the challenges that are being faced in consolidating data sets of the older PDS3 version of the standards with the new PDS4 deliveries into a single data model mapping to ensure transparent access to the data for users and services whilst maintaining a high performance.

  11. Planetary Magnetism

    International Nuclear Information System (INIS)

    Russell, C.T.

    1980-01-01

    Planetary spacecraft have now probed the magnetic fields of all the terrestrial planets, the moon, Jupiter, and Saturn. These measurements reveal that dynamos are active in at least four of the planets, Mercury, the earth, Jupiter, and Saturn but that Venus and Mars appear to have at most only very weak planetary magnetic fields. The moon may have once possessed an internal dynamo, for the surface rocks are magnetized. The large satellites of the outer solar system are candidates for dynamo action in addition to the large planets themselves. Of these satellites the one most likely to generate its own internal magnetic field is Io

  12. Planetary Torque in 3D Isentropic Disks

    International Nuclear Information System (INIS)

    Fung, Jeffrey; Masset, Frédéric; Velasco, David; Lega, Elena

    2017-01-01

    Planetary migration is inherently a three-dimensional (3D) problem, because Earth-size planetary cores are deeply embedded in protoplanetary disks. Simulations of these 3D disks remain challenging due to the steep resolution requirements. Using two different hydrodynamics codes, FARGO3D and PEnGUIn, we simulate disk–planet interaction for a one to five Earth-mass planet embedded in an isentropic disk. We measure the torque on the planet and ensure that the measurements are converged both in resolution and between the two codes. We find that the torque is independent of the smoothing length of the planet’s potential ( r s ), and that it has a weak dependence on the adiabatic index of the gaseous disk ( γ ). The torque values correspond to an inward migration rate qualitatively similar to previous linear calculations. We perform additional simulations with explicit radiative transfer using FARGOCA, and again find agreement between 3D simulations and existing torque formulae. We also present the flow pattern around the planets that show active flow is present within the planet’s Hill sphere, and meridional vortices are shed downstream. The vertical flow speed near the planet is faster for a smaller r s or γ , up to supersonic speeds for the smallest r s and γ in our study.

  13. The remarkably high excitation planetary nebula GC 6537.

    Science.gov (United States)

    Aller, L H; Hung, S; Feibelman, W A

    1999-05-11

    NGC 6537 is an unusually high excitation point symmetric planetary nebula with a rich spectrum. Its kinematical structures are of special interest. We are here primarily concerned with the high resolution spectrum as revealed by the Hamilton echelle Spectrograph at Lick Observatory (resolution approximately 0.2 A) and supplemented by UV and near-UV data. These extensive data permit a determination of interstellar extinction, plasma diagnostics, and ionic concentrations. The photoionization models that have been used successfully for many planetary nebulae are not entirely satisfactory here. The plasma electron temperature of a photoionization model cannot much exceed 20,000 K, but plasma diagnostics show that regions emitting radiation of highly ionized atoms such as [NeIV] and [NeV] are much hotter, showing that shock excitation must be important, as suggested by the remarkable kinematics of this object. Hence, instead of employing a strict photoionization model, we are guided by the nebular diagnostics, which reveal how electron temperature varies with ionization potential and accommodates density effects. The predictions of the photoionization model may be useful in estimating ionization correction factor. In effect, we have estimated the chemical composition by using both photoionization and shock considerations.

  14. Planetary mass function and planetary systems

    Science.gov (United States)

    Dominik, M.

    2011-02-01

    With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the properties of their respective host stars. This can be accounted for by describing planet populations by means of a differential planetary mass-radius-orbit function, which together with the fraction of stars with given properties that are orbited by planets and the stellar mass function allows the derivation of all statistics for any considered sample. These fundamental functions provide a framework for comparing statistics that result from different observing techniques and campaigns which all have their very specific selection procedures and detection efficiencies. Moreover, recent results both from gravitational microlensing campaigns and radial-velocity surveys of stars indicate that planets tend to cluster in systems rather than being the lonely child of their respective parent star. While planetary multiplicity in an observed system becomes obvious with the detection of several planets, its quantitative assessment however comes with the challenge to exclude the presence of further planets. Current exoplanet samples begin to give us first hints at the population statistics, whereas pictures of planet parameter space in its full complexity call for samples that are 2-4 orders of magnitude larger. In order to derive meaningful statistics, however, planet detection campaigns need to be designed in such a way that well-defined fully deterministic target selection, monitoring and detection criteria are applied. The probabilistic nature of gravitational microlensing makes this technique an illustrative example of all the encountered challenges and uncertainties.

  15. Planetary Simulation Chambers bring Mars to laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Mateo-Marti, E.

    2016-07-01

    Although space missions provide fundamental and unique knowledge for planetary exploration, they are always costly and extremely time-consuming. Due to the obvious technical and economical limitations of in-situ planetary exploration, laboratory simulations are among the most feasible research options for making advances in planetary exploration. Therefore, laboratory simulations of planetary environments are a necessary and complementary option to expensive space missions. Simulation chambers are economical, more versatile, and allow for a higher number of experiments than space missions. Laboratory-based facilities are able to mimic the conditions found in the atmospheres and on the surfaces of a majority of planetary objects. Number of relevant applications in Mars planetary exploration will be described in order to provide an understanding about the potential and flexibility of planetary simulation chambers systems: mainly, stability and presence of certain minerals on Mars surface; and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will be a promising tools and necessary platform to design future planetary space mission and to validate in-situ measurements from orbital or rover observations. (Author)

  16. Vertical Distribution of Radiation and Energy Balance Partitioning Within and Above a Lodgepole Pine Stand Recovering from a Recent Insect Attack

    Science.gov (United States)

    Emmel, Carmen; Paul-Limoges, Eugenie; Black, Thomas Andrew; Christen, Andreas

    2013-11-01

    The current outbreak of mountain pine beetle (MPB) that started in the late 1990s in British Columbia, Canada, is the largest ever recorded in the north American native habitat of the beetle. The killing of trees is expected to change the vertical distribution of net radiation () and the partitioning of latent () and sensible () heat fluxes in the different layers of an attacked forest canopy. During an intensive observation period in the summer of 2010, eddy-covariance flux and radiation measurements were made at seven heights from ground level up to 1.34 times the canopy height in an MPB-attacked open-canopy forest stand in the interior of British Columbia, Canada. The lodgepole pine dominated stand with a rich secondary structure (trees and understorey not killed by the beetle) was first attacked by the MPB in 2003 and received no management. In this study, the vertical distribution of the energy balance components and their sources and sinks were analyzed and energy balance closure (EBC) was determined for various levels within the canopy. The low stand density resulted in approximately 60 % of the shortwave irradiance and 50 % of the daily total reaching the ground. Flux divergence calculations indicated relatively strong sources of latent heat at the ground and where the secondary structure was located. Only very weak sources of latent heat were found in the upper part of the canopy, which was mainly occupied by dead lodgepole pine trees. was the dominant term throughout the canopy, and the Bowen ratio () increased with height in the canopy. Soil heat flux () accounted for approximately 4 % of . Sensible heat storage in the air () was the largest of the energy balance storage components in the upper canopy during daytime, while in the lower canopy sensible heat storage in the boles () and biochemical energy storage () were the largest terms. was almost constant from the bottom to above the canopy. , and latent heat storage in the air () varied more than

  17. Response of normal stem cells to ionizing radiation: A balance between homeostasis and genomic stability

    International Nuclear Information System (INIS)

    Harfouche, G.; Martin, M.T.

    2010-01-01

    Stem cells have been described in most adult tissues, where they play a key role in maintaining tissue homeostasis. As they self-renew throughout life, accumulating genetic anomalies can compromise their genomic integrity and potentially give rise to cancer. Stem cells (SCs) may thus be a major target of radiation carcinogenesis. In addition, unrepaired genotoxic damage may cause cell death and stem cell pool depletion, impairing lineage functionality and accelerating aging. Developments in SC biology enabled the characterization of the responses of stem cells to genotoxic stress and their role in tissue damage. We here examine how these cells react to ionizing radiation (IR), and more specifically their radiosensitivity, stress signaling and DNA repair. We first review embryonic SCs, as a paradigm of primitive pluri-potent cells, then three adult tissues, bone marrow, skin and intestine, capable of long-term regeneration and at high risk for acute radiation syndromes and long-term carcinogenesis. We discuss IR disruption of the fine balance between maintenance of tissue homeostasis and genomic stability. We show that stem cell radiosensitivity does not follow a unique model, but differs notably according to the turnover rates of the tissues. (authors)

  18. Model planetary nebulae: the effect of shadowed filaments on low ionization potential ion radiation

    International Nuclear Information System (INIS)

    Katz, A.

    1977-01-01

    Previous homogeneous model planetary nebulae calculations No. 4 have yielded emission strengths for low ionization potential No. 4 ions which are considerably lower than those observed. Several attempts were to correct this problem by the inclusion of optically thin condensations, the use of energy flux distributions from stellar model calculations instead of blackbody spectrum stars, and the inclusion of dust in the nebulae. The effect that shadowed filaments have on the ionization and thermal structure of model nebulae and the resultant line strengths are considered. These radial filaments are shielded from the direct stellar ionizing radiation by optically thick condensations in the nebula. Theoretical observational evidence exists for the presence of condensations and filaments. Since the only source of ionizing photons in the shadowed filaments is due to diffuse photons produced by recombination, ions of lower ionization potential are expected to exist there in greater numbers than those found in the rest of the nebula. This leads to increased line strengths from these ions and increases their values to match the observational values. It is shown that these line strengths in the filaments increase by over one to two orders of magnitude relative to values found in homogeneous models. This results in an increase of approximately one order of magnitude for these lines when contributions from both components of the nebula are considered. The parameters that determine the exact value of the increase are the radial location of the filaments in the nebula and the fraction of the nebular volume occupied by the filaments

  19. Radiation Belts of Antiparticles in Planetary Magnetospheres

    Science.gov (United States)

    Pugacheva, G. I.; Gusev, A. A.; Jayanthi, U. B.; Martin, I. M.; Spjeldvik, W. N.

    2007-05-01

    The Earth's radiation belts could be populated, besides with electrons and protons, also by antiparticles, such as positrons (Basilova et al., 1982) and antiprotons (pbar). Positrons are born in the decay of pions that are directly produced in nuclear reactions of trapped relativistic inner zone protons with the residual atmosphere at altitudes in the range of about 500 to 3000 km over the Earth's surface. Antiprotons are born by high energy (E > 6 GeV) cosmic rays in p+p - p+p+p+ pbar and in p+p - p+p+n+nbar reactions. The trapping and storage of these charged anti-particles in the magnetosphere result in radiation belts similar to the classical Van Allen belts of protons and electrons. We describe the mathematical techniques used for numerical simulation of the trapped positron and antiproton belt fluxes. The pion and antiproton yields were simulated on the basis of the Russian nuclear reaction computer code MSDM, a Multy Stage Dynamical Model, Monte Carlo code, (i.e., Dementyev and Sobolevsky, 1999). For estimates of positron flux there we have accounted for ionisation, bremsstrahlung, and synchrotron energy losses. The resulting numerical estimates show that the positron flux with energy >100 MeV trapped into the radiation belt at L=1.2 is of the order ~1000 m-2 s-1 sr-1, and that it is very sensitive to the shape of the trapped proton spectrum. This confined positron flux is found to be greater than that albedo, not trapped, mixed electron/positron flux of about 50 m-2 s-1 sr-1 produced by CR in the same region at the top of the geomagnetic field line at L=1.2. As we show in report, this albedo flux also consists mostly of positrons. The trapped antiproton fluxes produced by CR in the Earth's upper rarified atmosphere were calculated in the energy range from 10 MeV to several GeV. In the simulations we included a mathematic consideration of the radial diffusion process, both an inner and an outer antiproton source, losses of particles due to ionization process

  20. Radiation Tolerant Temperature-Invariant Scintillation Modules, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation detectors are an invaluable tool for space applications spanning planetary science, astrophysics, heliophysics, space weather, and dosimetry for human...

  1. Energy balance of controlled thermonuclear fusion

    International Nuclear Information System (INIS)

    Hashmi, M.; Staudenmaier, G.

    2000-01-01

    It is shown that a discrepancy and incompatibility persist between basic physics and fusion-literature regarding the radiation losses from a thermonuclear plasma. Whereas the fusion-literature neglects the excitation or line radiation completely, according to basic physics it depends upon the prevailing conditions and cannot be neglected in general. Moreover, for a magnetized plasma, while the fusion-literature assumes a self-absorption or reabsorption of cyclotron or synchrotron radiation emitted by the electrons spiraling along the magnetic field, the basic physics does not allow any effective reabsorption of cyclotron or synchrotron radiation. As is demonstrated, fallacious assumptions and notions, which somehow or other crept into the fusion-literature, are responsible for this discrepancy. In the present work, the theory is corrected. On the grounds of basic physics, a complete energy balance of magnetized and non-magnetized plasmas is presented for pulsed, stationary and self-sustaining operations by taking into account the energy release by reactions of light nuclei as well as different kinds of diffusive (conduction) and radiative (bremsstrahlung, cyclotron or synchrotron radiation and excitation radiation) energy losses. Already the energy losses by radiation make the energy balance negative. Hence, a fusion reactor-an energy producing device-seems to be beyond the realms of realization. (orig.)

  2. Space and Planetary Resources

    Science.gov (United States)

    Abbud-Madrid, Angel

    2018-02-01

    The space and multitude of celestial bodies surrounding Earth hold a vast wealth of resources for a variety of space and terrestrial applications. The unlimited solar energy, vacuum, and low gravity in space, as well as the minerals, metals, water, atmospheric gases, and volatile elements on the Moon, asteroids, comets, and the inner and outer planets of the Solar System and their moons, constitute potential valuable resources for robotic and human space missions and for future use in our own planet. In the short term, these resources could be transformed into useful materials at the site where they are found to extend mission duration and to reduce the costly dependence from materials sent from Earth. Making propellants and human consumables from local resources can significantly reduce mission mass and cost, enabling longer stays and fueling transportation systems for use within and beyond the planetary surface. Use of finely grained soils and rocks can serve for habitat construction, radiation protection, solar cell fabrication, and food growth. The same material could also be used to develop repair and replacement capabilities using advanced manufacturing technologies. Following similar mining practices utilized for centuries on Earth, identifying, extracting, and utilizing extraterrestrial resources will enable further space exploration, while increasing commercial activities beyond our planet. In the long term, planetary resources and solar energy could also be brought to Earth if obtaining these resources locally prove to be no longer economically or environmentally acceptable. Throughout human history, resources have been the driving force for the exploration and settling of our planet. Similarly, extraterrestrial resources will make space the next destination in the quest for further exploration and expansion of our species. However, just like on Earth, not all challenges are scientific and technological. As private companies start working toward

  3. The estimation of the atmospheric longwave radiation

    NARCIS (Netherlands)

    Nowak, H.; Wit, de M.H.; Schellen, H.L.

    1994-01-01

    The paper presents a review of some models to calculate the intensity of the atmospheric longwave radiation upon horizontal plane. This radiation (called also thermal or infrared radiation) may have significant influence on the radiative balance and subseuquently on the thermal balance of the

  4. The Planetary Science Archive (PSA): Exploration and discovery of scientific datasets from ESA's planetary missions

    Science.gov (United States)

    Vallat, C.; Besse, S.; Barbarisi, I.; Arviset, C.; De Marchi, G.; Barthelemy, M.; Coia, D.; Costa, M.; Docasal, R.; Fraga, D.; Heather, D. J.; Lim, T.; Macfarlane, A.; Martinez, S.; Rios, C.; Vallejo, F.; Said, J.

    2017-09-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific datasets through various interfaces at http://psa.esa.int. All datasets are scientifically peer-reviewed by independent scientists, and are compliant with the Planetary Data System (PDS) standards. The PSA has started to implement a number of significant improvements, mostly driven by the evolution of the PDS standards, and the growing need for better interfaces and advanced applications to support science exploitation.

  5. Ethics and the Potential Conflicts between Astrobiology, Planetary Protection, and Commercial Use of Space

    Directory of Open Access Journals (Sweden)

    Erik Persson

    2017-05-01

    Full Text Available A high standard of planetary protection is important for astrobiology, though the risk for contamination can never be zero. It is therefore important to find a balance. If extraterrestrial life has a moral standing in its own right, it will also affect what we have to do to protect it. The questions of how far we need to go to protect extraterrestrial life will be even more acute and complicated when the time comes to use habitable worlds for commercial purposes. There will also be conflicts between those who want to set a world aside for more research and those who want to give the green light for development. I believe it is important to be proactive in relation to these issues. The aim of my project is therefore to identify, elucidate, and if possible, suggest solutions to potential conflicts between astrobiology, planetary protection, and commercial use of space.

  6. Photoneutron spectrum measured with Bonner Spheres in Planetary method mode

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Velazquez F, J., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado en Ciencias Biologico Agropecuarias, Carretera Tepic-Compostela Km 9, 63780 Jalisco-Nayarit (Mexico)

    2012-10-15

    We measured the spectrum of photoneutrons at 100 cm isocenter linear accelerator (Linac) Varian ix operating at 15 MV Bremsstrahlung mode. In this process was used a radiation field of 20 x 20 cm{sup 2} at a depth of 5 cm in a solid water phantom with dimensions of 30 x 30 x 15 cm{sup 3}. The measurement was performed with a system using it Bonner Spheres spectrometric method Planetary mode. As neutron detector of the spectrometer is used thermoluminescent dosimeters pairs of type 600 and 700. (Author)

  7. Photoneutron spectrum measured with Bonner Spheres in Planetary method mode

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    We measured the spectrum of photoneutrons at 100 cm isocenter linear accelerator (Linac) Varian ix operating at 15 MV Bremsstrahlung mode. In this process was used a radiation field of 20 x 20 cm 2 at a depth of 5 cm in a solid water phantom with dimensions of 30 x 30 x 15 cm 3 . The measurement was performed with a system using it Bonner Spheres spectrometric method Planetary mode. As neutron detector of the spectrometer is used thermoluminescent dosimeters pairs of type 600 and 700. (Author)

  8. Number of planetary nebulae in our galaxy

    International Nuclear Information System (INIS)

    Alloin, D.; Cruz-Gonzalez, C.; Peimbert, M.

    1976-01-01

    It is found that the contribution to the ionization of the interstellar medium due to planetary nebulae is from one or two orders of magnitude smaller than that due to O stars. The mass return to the interstellar medium due to planetary nebulae is investigated, and the birth rate of white dwarfs and planetary nebulae are compared. Several arguments are given against the possibility that the infrared sources detected by Becklin and Neugebauer in the direction of the galactic center are planetary nebulae

  9. Technology under Planetary Protection Research (PPR)

    Data.gov (United States)

    National Aeronautics and Space Administration — Planetary protection involves preventing biological contamination on both outbound and sample return missions to other planetary bodies. Numerous areas of research...

  10. Multi-Beam Surface Lidar for Lunar and Planetary Mapping

    Science.gov (United States)

    Bufton, Jack L.; Garvin, James B.

    1998-01-01

    Surface lidar techniques are now being demonstrated in low Earth orbit with a single beam of pulsed laser radiation at 1064 nm that profiles the vertical structure of Earth surface landforms along the nadir track of a spacecraft. In addition, a profiling laser altimeter, called MOLA, is operating in elliptical Martian orbit and returning surface topography data. These instruments form the basis for suggesting an improved lidar instrument that employs multiple beams for extension of sensor capabilities toward the goal of true, 3-dimensional mapping of the Moon or other similar planetary surfaces. In general the lidar waveform acquired with digitization of a laser echo can be used for laser distance measurement (i.e. range-to-the-surface) by time-of-flight measurement and for surface slope and shape measurements by examining the detailed lidar waveform. This is particularly effective when the intended target is the lunar surface or another planetary body free of any atmosphere. The width of the distorted return pulse is a first order measure of the surface incidence angle, a combination of surface slope and laser beam pointing. Assuming an independent and absolute (with respect to inertial space) measurement of laser beam pointing on the spacecraft, it is possible to derive a surface slope with-respect-to the mean planetary surface or its equipotential gravity surface. Higher-order laser pulse distortions can be interpreted in terms of the vertical relief of the surface or reflectivity variations within the area of the laser beam footprint on the surface.

  11. Virtual reality and planetary exploration

    Science.gov (United States)

    McGreevy, Michael W.

    Exploring planetary environments is central to NASA's missions and goals. A new computing technology called Virtual Reality has much to offer in support of planetary exploration. This technology augments and extends human presence within computer-generated and remote spatial environments. Historically, NASA has been a leader in many of the fundamental concepts and technologies that comprise Virtual Reality. Indeed, Ames Research Center has a central role in the development of this rapidly emerging approach to using computers. This ground breaking work has inspired researchers in academia, industry, and the military. Further, NASA's leadership in this technology has spun off new businesses, has caught the attention of the international business community, and has generated several years of positive international media coverage. In the future, Virtual Reality technology will enable greatly improved human-machine interactions for more productive planetary surface exploration. Perhaps more importantly, Virtual Reality technology will democratize the experience of planetary exploration and thereby broaden understanding of, and support for, this historic enterprise.

  12. Virtual reality and planetary exploration

    Science.gov (United States)

    Mcgreevy, Michael W.

    1992-01-01

    Exploring planetary environments is central to NASA's missions and goals. A new computing technology called Virtual Reality has much to offer in support of planetary exploration. This technology augments and extends human presence within computer-generated and remote spatial environments. Historically, NASA has been a leader in many of the fundamental concepts and technologies that comprise Virtual Reality. Indeed, Ames Research Center has a central role in the development of this rapidly emerging approach to using computers. This ground breaking work has inspired researchers in academia, industry, and the military. Further, NASA's leadership in this technology has spun off new businesses, has caught the attention of the international business community, and has generated several years of positive international media coverage. In the future, Virtual Reality technology will enable greatly improved human-machine interactions for more productive planetary surface exploration. Perhaps more importantly, Virtual Reality technology will democratize the experience of planetary exploration and thereby broaden understanding of, and support for, this historic enterprise.

  13. RAPID WATER LOSS CAN EXTEND THE LIFETIME OF PLANETARY HABITABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Takanori; Abe, Yutaka [Department of Earth and Planetary Science, The University of Tokyo, Tokyo 113-0033 (Japan); Genda, Hidenori [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Zahnle, Kevin J., E-mail: koda@eps.s.u-tokyo.ac.jp [Space Science and Astrobiology Division, NASA Ames Research Center, California 94035 (United States)

    2015-10-20

    Two habitable planetary states are proposed: an aqua planet like the Earth and a land planet that has a small amount of water. Land planets keep liquid water under larger solar radiation compared to aqua planets. Water loss may change an aqua planet into a land planet, and the planet can remain habitable for a longer time than if it had remained an aqua planet. We calculate planetary evolution with hydrogen escape for different initial water inventories and different distances from the central star. We find that there are two conditions necessary to evolve an aqua planet into a land planet: the critical amount of water on the surface (M{sub ml}) consistent with a planet being a land planet, and the critical amount of water vapor in the atmosphere (M{sub cv}) that defines the onset of the runaway greenhouse state. We find that Earth-sized aqua planets with initial oceans <10% of the Earth's can evolve into land planets if M{sub cv} = 3 m in precipitable water and M{sub ml} = 5% of the Earth's ocean mass. Such planets can keep liquid water on their surface for another 2 Gyr. The initial amount of water and M{sub cv} are shown to be important dividing parameters of the planetary evolution path. Our results indicate that massive hydrogen escape could give a fresh start as another kind of habitable planet rather than the end of its habitability.

  14. RAPID WATER LOSS CAN EXTEND THE LIFETIME OF PLANETARY HABITABILITY

    International Nuclear Information System (INIS)

    Kodama, Takanori; Abe, Yutaka; Genda, Hidenori; Zahnle, Kevin J.

    2015-01-01

    Two habitable planetary states are proposed: an aqua planet like the Earth and a land planet that has a small amount of water. Land planets keep liquid water under larger solar radiation compared to aqua planets. Water loss may change an aqua planet into a land planet, and the planet can remain habitable for a longer time than if it had remained an aqua planet. We calculate planetary evolution with hydrogen escape for different initial water inventories and different distances from the central star. We find that there are two conditions necessary to evolve an aqua planet into a land planet: the critical amount of water on the surface (M ml ) consistent with a planet being a land planet, and the critical amount of water vapor in the atmosphere (M cv ) that defines the onset of the runaway greenhouse state. We find that Earth-sized aqua planets with initial oceans <10% of the Earth's can evolve into land planets if M cv = 3 m in precipitable water and M ml = 5% of the Earth's ocean mass. Such planets can keep liquid water on their surface for another 2 Gyr. The initial amount of water and M cv are shown to be important dividing parameters of the planetary evolution path. Our results indicate that massive hydrogen escape could give a fresh start as another kind of habitable planet rather than the end of its habitability

  15. Spectral Feature Analysis of Minerals and Planetary Surfaces in an Introductory Planetary Science Course

    Science.gov (United States)

    Urban, Michael J.

    2013-01-01

    Using an ALTA II reflectance spectrometer, the USGS digital spectral library, graphs of planetary spectra, and a few mineral hand samples, one can teach how light can be used to study planets and moons. The author created the hands-on, inquiry-based activity for an undergraduate planetary science course consisting of freshman to senior level…

  16. NASA Planetary Science Summer School: Preparing the Next Generation of Planetary Mission Leaders

    Science.gov (United States)

    Lowes, L. L.; Budney, C. J.; Sohus, A.; Wheeler, T.; Urban, A.; NASA Planetary Science Summer School Team

    2011-12-01

    Sponsored by NASA's Planetary Science Division, and managed by the Jet Propulsion Laboratory, the Planetary Science Summer School prepares the next generation of engineers and scientists to participate in future solar system exploration missions. Participants learn the mission life cycle, roles of scientists and engineers in a mission environment, mission design interconnectedness and trade-offs, and the importance of teamwork. For this professional development opportunity, applicants are sought who have a strong interest and experience in careers in planetary exploration, and who are science and engineering post-docs, recent PhDs, and doctoral students, and faculty teaching such students. Disciplines include planetary science, geoscience, geophysics, environmental science, aerospace engineering, mechanical engineering, and materials science. Participants are selected through a competitive review process, with selections based on the strength of the application and advisor's recommendation letter. Under the mentorship of a lead engineer (Dr. Charles Budney), students select, design, and develop a mission concept in response to the NASA New Frontiers Announcement of Opportunity. They develop their mission in the JPL Advanced Projects Design Team (Team X) environment, which is a cross-functional multidisciplinary team of professional engineers that utilizes concurrent engineering methodologies to complete rapid design, analysis and evaluation of mission concept designs. About 36 students participate each year, divided into two summer sessions. In advance of an intensive week-long session in the Project Design Center at JPL, students select the mission and science goals during a series of six weekly WebEx/telecons, and develop a preliminary suite of instrumentation and a science traceability matrix. Students assume both a science team and a mission development role with JPL Team X mentors. Once at JPL, students participate in a series of Team X project design sessions

  17. Planetary Torque in 3D Isentropic Disks

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Jeffrey [Department of Astronomy, University of California at Berkeley, Campbell Hall, Berkeley, CA 94720-3411 (United States); Masset, Frédéric; Velasco, David [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad s/n, 62210 Cuernavaca, Mor. (Mexico); Lega, Elena, E-mail: jeffrey.fung@berkeley.edu [Université de la Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange UMR 7293, Nice (France)

    2017-03-01

    Planetary migration is inherently a three-dimensional (3D) problem, because Earth-size planetary cores are deeply embedded in protoplanetary disks. Simulations of these 3D disks remain challenging due to the steep resolution requirements. Using two different hydrodynamics codes, FARGO3D and PEnGUIn, we simulate disk–planet interaction for a one to five Earth-mass planet embedded in an isentropic disk. We measure the torque on the planet and ensure that the measurements are converged both in resolution and between the two codes. We find that the torque is independent of the smoothing length of the planet’s potential ( r {sub s}), and that it has a weak dependence on the adiabatic index of the gaseous disk ( γ ). The torque values correspond to an inward migration rate qualitatively similar to previous linear calculations. We perform additional simulations with explicit radiative transfer using FARGOCA, and again find agreement between 3D simulations and existing torque formulae. We also present the flow pattern around the planets that show active flow is present within the planet’s Hill sphere, and meridional vortices are shed downstream. The vertical flow speed near the planet is faster for a smaller r {sub s} or γ , up to supersonic speeds for the smallest r {sub s} and γ in our study.

  18. Gravitational waves emitted by extrasolar planetary systems

    International Nuclear Information System (INIS)

    Berti, E.; Ferrari, V.

    2001-01-01

    The recently discovered Extrasolar Planetary Systems (EPS's) are potentially interesting sources of gravitational waves, since they are very close to Earth (at distances ∼ 10 pc), and their orbital features and positions in the sky are quite well known. As a first estimate, we compute the orbital emission of these systems using the quadrupole formula. Then we show that, in principle, the orbiting planet could resonantly excite the quasi-normal modes of the central star. We use the general-relativistic theory of stellar pulsations to estimate the effects of such a resonance on the gravitational-wave emission of the system. We also consider radiation-reaction effects on the orbital evolution, and give upper limits on the timescales required for a planet to get off-resonance. (author)

  19. The NASA Regional Planetary Image Facility (RPIF) Network: A Key Resource for Accessing and Using Planetary Spatial Data

    Science.gov (United States)

    Hagerty, J. J.

    2017-12-01

    The role of the NASA Regional Planetary Image Facility (RPIF) Network is evolving as new science-ready spatial data products continue to be created and as key historical planetary data sets are digitized. Specifically, the RPIF Network is poised to serve specialized knowledge and services in a user-friendly manner that removes most barriers to locating, accessing, and exploiting planetary spatial data, thus providing a critical data access role within a spatial data infrastructure. The goal of the Network is to provide support and training to a broad audience of planetary spatial data users. In an effort to meet the planetary science community's evolving needs, we are focusing on the following objectives: Maintain and improve the delivery of historical data accumulated over the past four decades so as not to lose critical, historical information. This is being achieved by systematically digitizing fragile materials, allowing increased access and preserving them at the same time. Help users locate, access, visualize, and exploit planetary science data. Many of the facilities have begun to establish Guest User Facilities that allow researchers to use and/or be trained on GIS equipment and other specialized tools like Socet Set/GXP photogrammetry workstations for generating digital elevation maps. Improve the connection between the Network nodes while also leveraging the unique resources of each node. To achieve this goal, each facility is developing and sharing searchable databases of their collections, including robust metadata in a standards compliant way. Communicate more effectively and regularly with the planetary science community in an effort to make potential users aware of resources and services provided by the Network, while also engaging community members in discussions about community needs. Provide a regional resource for the science community, colleges, universities, museums, media, and the public to access planetary data. Introduce new strategies for

  20. Radiation -- A Cosmic Hazard to Human Habitation in Space

    Science.gov (United States)

    Lewis, Ruthan; Pellish, Jonathan

    2017-01-01

    Radiation exposure is one of the greatest environmental threats to the performance and success of human and robotic space missions. Radiation permeates all space and aeronautical systems, challenges optimal and reliable performance, and tests survival and survivability. We will discuss the broad scope of research, technological, and operational considerations to forecast and mitigate the effects of the radiation environment for deep space and planetary exploration.

  1. Classification of ISO SWS 01 spectra of proto-planetary nebulae: a search for precursors of planetary nebulae with [WR] central stars

    OpenAIRE

    Szczerba, R.; Stasi{ń}ska, G.; Siódmiak, N.; Górny, S. K.

    2002-01-01

    We have analyzed ISO SWS 01 observations for 61 proto-planetary nebulae candidates and classified their spectra according to their dominant chemistry. On the basis of our classification and the more general classification of SWS 01 spectra by Kraemer et al. (2002) we discuss the connection between proto-planetary nebulae candidates and planetary nebulae, with emphasis on possible precursors of planetary nebulae with [WR] central stars.

  2. An ecological compass for planetary engineering.

    Science.gov (United States)

    Haqq-Misra, Jacob

    2012-10-01

    Proposals to address present-day global warming through the large-scale application of technology to the climate system, known as geoengineering, raise questions of environmental ethics relevant to the broader issue of planetary engineering. These questions have also arisen in the scientific literature as discussions of how to terraform a planet such as Mars or Venus in order to make it more Earth-like and habitable. Here we draw on insights from terraforming and environmental ethics to develop a two-axis comparative tool for ethical frameworks that considers the intrinsic or instrumental value placed upon organisms, environments, planetary systems, or space. We apply this analysis to the realm of planetary engineering, such as terraforming on Mars or geoengineering on present-day Earth, as well as to questions of planetary protection and space exploration.

  3. Instrumentation For Multiple Radiation Detection Based On Novel Mercurous Halides For Nuclear Planetology, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation detectors that sense gamma and neutron radiation are critical to the exploration of planetary surface composition. Among the key technological challenges...

  4. Schottky barrier CdTe(Cl) detectors for planetary missions

    International Nuclear Information System (INIS)

    Eisen, Yosef; Floyd, Samuel

    2002-01-01

    Schottky barrier cadmium telluride (CdTe) radiation detectors of dimensions 2mm x 2mm x 1mm and segmented monolithic 3cm x 3 cm x 1mm are under study at GSFC for future NASA planetary instruments. These instruments will perform x-ray fluorescence spectrometry of the surface and monitor the solar x-ray flux spectrum, the excitation source for the characteristic x-rays emitted from the planetary body. The Near Earth Asteroid Rendezvous (NEAR) mission is the most recent example of such a remote sensing technique. Its x-ray fluorescence detectors were gas proportional counters with a back up Si PIN solar monitor. Analysis of NEAR data has shown the necessity to develop a solar x-ray detector with efficiency extending to 30keV. Proportional counters and Si diodes have low sensitivity above 9keV. Our 2mm x 2mm x 1mm CdTe operating at -30 degree sign C possesses an energy resolution of 250eV FWHM for 55Fe with unit efficiency to up to 30keV. This is an excellent candidate for a solar monitor. Another ramification of the NEAR data is a need to develop a large area detector system, 20-30 cm2, with cosmic ray charged particle rejection, for measuring the characteristic radiation. A 3cm x 3cm x 1mm Schottky CdTe segmented monolithic detector is under investigation for this purpose. A tiling of 2-3 such detectors will result in the desired area. The favorable characteristics of Schottky CdTe detectors, the system design complexities when using CdTe and its adaptation to future missions will be discussed

  5. Biomass-based negative emissions difficult to reconcile with planetary boundaries

    Science.gov (United States)

    Heck, Vera; Gerten, Dieter; Lucht, Wolfgang; Popp, Alexander

    2018-01-01

    Under the Paris Agreement, 195 nations have committed to holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to strive to limit the increase to 1.5 °C (ref. 1). It is noted that this requires "a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the century"1. This either calls for zero greenhouse gas (GHG) emissions or a balance between positive and negative emissions (NE)2,3. Roadmaps and socio-economic scenarios compatible with a 2 °C or 1.5 °C goal depend upon NE via bioenergy with carbon capture and storage (BECCS) to balance remaining GHG emissions4-7. However, large-scale deployment of BECCS would imply significant impacts on many Earth system components besides atmospheric CO2 concentrations8,9. Here we explore the feasibility of NE via BECCS from dedicated plantations and potential trade-offs with planetary boundaries (PBs)10,11 for multiple socio-economic pathways. We show that while large-scale BECCS is intended to lower the pressure on the PB for climate change, it would most likely steer the Earth system closer to the PB for freshwater use and lead to further transgression of the PBs for land-system change, biosphere integrity and biogeochemical flows.

  6. On planetary nebulae as sources of carbon dust: Infrared emission from planetary nebulae of the galactic halo

    International Nuclear Information System (INIS)

    Dinerstein, H.L.; Lester, D.F.

    1990-01-01

    Researchers examine here the characteristics of the infrared emission from the four planetary nebulae which are believed on the basis of their low overall metallicities to belong to the halo population. These nebulae are of particular interest because they are the most metal-poor ionized nebulae known in our Galaxy, and offer the opportunity to probe possible dependences of the dust properties on nebular composition. Researchers present fluxes extracted from co-addition of the IRAS data, as well as ground-based near infrared measurements. Each of the four halo objects, including the planetary nebula in the globular cluster M15, is detected in at least one infrared band. Researchers compare the estimated infrared excesses of these nebulae (IRE, the ratio of measured infrared power to the power available in the form of resonantly-trapped Lyman alpha photons) to those of disk planetary nebulae with similar densities but more normal abundances. Three of the halo planetaries have IRE values similar to those of the disk nebulae, despite the fact that their Fe- and Si-peak gas phase abundances are factors of 10 to 100 lower. However, these halo nebulae have normal or elevated C/H ratios, due to nuclear processing and mixing in their red giant progenitors. Unlike the other halo planetaries, DDDM1 is deficient in carbon as well as in the other light metals. This nebula has a substantially lower IRE than the other halo planetaries, and may be truly dust efficient. Researchers suggest that the deficiency is due to a lack of the raw material for producing carbon-based grains, and that the main bulk constituent of the dust in these planetary nebulae is carbon

  7. A Study of Planetary Nebulae using the Faint Object Infrared Camera for the SOFIA Telescope

    Science.gov (United States)

    Davis, Jessica

    2012-01-01

    A planetary nebula is formed following an intermediate-mass (1-8 solar M) star's evolution off of the main sequence; it undergoes a phase of mass loss whereby the stellar envelope is ejected and the core is converted into a white dwarf. Planetary nebulae often display complex morphologies such as waists or torii, rings, collimated jet-like outflows, and bipolar symmetry, but exactly how these features form is unclear. To study how the distribution of dust in the interstellar medium affects their morphology, we utilize the Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST) to obtain well-resolved images of four planetary nebulae--NGC 7027, NGC 6543, M2-9, and the Frosty Leo Nebula--at wavelengths where they radiate most of their energy. We retrieve mid infrared images at wavelengths ranging from 6.3 to 37.1 micron for each of our targets. IDL (Interactive Data Language) is used to perform basic analysis. We select M2-9 to investigate further; analyzing cross sections of the southern lobe reveals a slight limb brightening effect. Modeling the dust distribution within the lobes reveals that the thickness of the lobe walls is higher than anticipated, or rather than surrounding a vacuum surrounds a low density region of tenuous dust. Further analysis of this and other planetary nebulae is needed before drawing more specific conclusions.

  8. Planetary rovers robotic exploration of the solar system

    CERN Document Server

    Ellery, Alex

    2016-01-01

    The increasing adoption of terrain mobility – planetary rovers – for the investigation of planetary surfaces emphasises their central importance in space exploration. This imposes a completely new set of technologies and methodologies to the design of such spacecraft – and planetary rovers are indeed, first and foremost, spacecraft. This introduces vehicle engineering, mechatronics, robotics, artificial intelligence and associated technologies to the spacecraft engineer’s repertoire of skills. Planetary Rovers is the only book that comprehensively covers these aspects of planetary rover engineering and more. The book: • discusses relevant planetary environments to rover missions, stressing the Moon and Mars; • includes a brief survey of previous rover missions; • covers rover mobility, traction and control systems; • stresses the importance of robotic vision in rovers for both navigation and science; • comprehensively covers autonomous navigation, path planning and multi-rover formations on ...

  9. Planetary climates (princeton primers in climate)

    CERN Document Server

    Ingersoll, Andrew

    2013-01-01

    This concise, sophisticated introduction to planetary climates explains the global physical and chemical processes that determine climate on any planet or major planetary satellite--from Mercury to Neptune and even large moons such as Saturn's Titan. Although the climates of other worlds are extremely diverse, the chemical and physical processes that shape their dynamics are the same. As this book makes clear, the better we can understand how various planetary climates formed and evolved, the better we can understand Earth's climate history and future.

  10. Planetary protection in the framework of the Aurora exploration program

    Science.gov (United States)

    Kminek, G.

    The Aurora Exploration Program will give ESA new responsibilities in the field of planetary protection. Until now, ESA had only limited exposure to planetary protection from its own missions. With the proposed ExoMars and MSR missions, however, ESA will enter the realm of the highest planetary protection categories. As a consequence, the Aurora Exploration Program has initiated a number of activities in the field of planetary protection. The first and most important step was to establish a Planetary Protection Working Group (PPWG) that is advising the Exploration Program Advisory Committee (EPAC) on all matters concerning planetary protection. The main task of the PPWG is to provide recommendations regarding: Planetary protection for robotic missions to Mars; Planetary protection for a potential human mission to Mars; Review/evaluate standards & procedures for planetary protection; Identify research needs in the field of planetary protection. As a result of the PPWG deliberations, a number of activities have been initiated: Evaluation of the Microbial Diversity in SC Facilities; Working paper on legal issues of planetary protection and astrobiology; Feasibility study on a Mars Sample Return Containment Facility; Research activities on sterilization procedures; Training course on planetary protection (May, 2004); Workshop on sterilization techniques (fall 2004). In parallel to the PPWG, the Aurora Exploration Program has established an Ethical Working Group (EWG). This working group will address ethical issues related to astrobiology, planetary protection, and manned interplanetary missions. The recommendations of the working groups and the results of the R&D activities form the basis for defining planetary protection specification for Aurora mission studies, and for proposing modification and new inputs to the COSPAR planetary protection policy. Close cooperation and free exchange of relevant information with the NASA planetary protection program is strongly

  11. An Ion-Propelled Cubesat for Planetary Defense and Planetary Science

    Science.gov (United States)

    Russell, Christopher T.; Wirz, Richard; Lai, Hairong; Li, Jian-Yang; Connors, Martin

    2017-04-01

    Small satellites can reduce the cost of launch by riding along with other payloads on a large rocket or being launched on a small rocket, but are perceived as having limited capabilities. This perception can be at least partially overcome by innovative design, including ample in-flight propulsion. This allows achieving multiple targets and adaptive exploration. Ion propulsion has been pioneered on Deep Space 1 and honed on the long-duration, multiple-planetary body mission Dawn. Most importantly, the operation of such a mission is now well- understood, including navigation, communication, and science operations for remote sensing. We examined different mission concepts that can be used for both planetary defense and planetary science near 1 AU. Such a spacecraft would travel in the region between Venus and Mars, allowing a complete inventory of material above, including objects down to about 10m diameter to be inventoried. The ion engines could be used to approach these bodies slowly and carefully and allow the spacecraft to map debris and follow its collisional evolution throughout its orbit around the Sun, if so desired. The heritage of Dawn operations experience enables the mission to be operated inexpensively, and the engineering heritage will allow it to be operated for many trips around the Sun.

  12. Non-planetary Science from Planetary Missions

    Science.gov (United States)

    Elvis, M.; Rabe, K.; Daniels, K.

    2015-12-01

    Planetary science is naturally focussed on the issues of the origin and history of solar systems, especially our own. The implications of an early turbulent history of our solar system reach into many areas including the origin of Earth's oceans, of ores in the Earth's crust and possibly the seeding of life. There are however other areas of science that stand to be developed greatly by planetary missions, primarily to small solar system bodies. The physics of granular materials has been well-studied in Earth's gravity, but lacks a general theory. Because of the compacting effects of gravity, some experiments desired for testing these theories remain impossible on Earth. Studying the behavior of a micro-gravity rubble pile -- such as many asteroids are believed to be -- could provide a new route towards exploring general principles of granular physics. These same studies would also prove valuable for planning missions to sample these same bodies, as techniques for anchoring and deep sampling are difficult to plan in the absence of such knowledge. In materials physics, first-principles total-energy calculations for compounds of a given stoichiometry have identified metastable, or even stable, structures distinct from known structures obtained by synthesis under laboratory conditions. The conditions in the proto-planetary nebula, in the slowly cooling cores of planetesimals, and in the high speed collisions of planetesimals and their derivatives, are all conditions that cannot be achieved in the laboratory. Large samples from comets and asteroids offer the chance to find crystals with these as-yet unobserved structures as well as more exotic materials. Some of these could have unusual properties important for materials science. Meteorites give us a glimpse of these exotic materials, several dozen of which are known that are unique to meteorites. But samples retrieved directly from small bodies in space will not have been affected by atmospheric entry, warmth or

  13. Migration-induced architectures of planetary systems.

    Science.gov (United States)

    Szuszkiewicz, Ewa; Podlewska-Gaca, Edyta

    2012-06-01

    The recent increase in number of known multi-planet systems gives a unique opportunity to study the processes responsible for planetary formation and evolution. Special attention is given to the occurrence of mean-motion resonances, because they carry important information about the history of the planetary systems. At the early stages of the evolution, when planets are still embedded in a gaseous disc, the tidal interactions between the disc and planets cause the planetary orbital migration. The convergent differential migration of two planets embedded in a gaseous disc may result in the capture into a mean-motion resonance. The orbital migration taking place during the early phases of the planetary system formation may play an important role in shaping stable planetary configurations. An understanding of this stage of the evolution will provide insight on the most frequently formed architectures, which in turn are relevant for determining the planet habitability. The aim of this paper is to present the observational properties of these planetary systems which contain confirmed or suspected resonant configurations. A complete list of known systems with such configurations is given. This list will be kept by us updated from now on and it will be a valuable reference for studying the dynamics of extrasolar systems and testing theoretical predictions concerned with the origin and the evolution of planets, which are the most plausible places for existence and development of life.

  14. Lessons learned from planetary science archiving

    Science.gov (United States)

    Zender, J.; Grayzeck, E.

    2006-01-01

    The need for scientific archiving of past, current, and future planetary scientific missions, laboratory data, and modeling efforts is indisputable. To quote from a message by G. Santayama carved over the entrance of the US Archive in Washington DC “Those who can not remember the past are doomed to repeat it.” The design, implementation, maintenance, and validation of planetary science archives are however disputed by the involved parties. The inclusion of the archives into the scientific heritage is problematic. For example, there is the imbalance between space agency requirements and institutional and national interests. The disparity of long-term archive requirements and immediate data analysis requests are significant. The discrepancy between the space missions archive budget and the effort required to design and build the data archive is large. An imbalance exists between new instrument development and existing, well-proven archive standards. The authors present their view on the problems and risk areas in the archiving concepts based on their experience acquired within NASA’s Planetary Data System (PDS) and ESA’s Planetary Science Archive (PSA). Individual risks and potential problem areas are discussed based on a model derived from a system analysis done upfront. The major risk for a planetary mission science archive is seen in the combination of minimal involvement by Mission Scientists and inadequate funding. The authors outline how the risks can be reduced. The paper ends with the authors view on future planetary archive implementations including the archive interoperability aspect.

  15. POET: A Model for Planetary Orbital Evolution Due to Tides on Evolving Stars

    Science.gov (United States)

    Penev, Kaloyan; Zhang, Michael; Jackson, Brian

    2014-06-01

    We make publicly available an efficient, versatile, easy to use and extend tool for calculating the evolution of circular aligned planetary orbits due to the tidal dissipation in the host star. This is the first model to fully account for the evolution of the angular momentum of the stellar convective envelope by the tidal coupling, the transfer of angular momentum between the stellar convective and radiative zones, the effects of the stellar evolution on the tidal dissipation efficiency and stellar core and envelope spins, the loss of stellar convective zone angular momentum to a magnetically launched wind and frequency dependent tidal dissipation. This is only a first release and further development is under way to allow calculating the evolution of inclined and eccentric orbits, with the latter including the tidal dissipation in the planet and its feedback on planetary structure. Considerable effort has been devoted to providing extensive documentation detailing both the usage and the complete implementation details, in order to make it as easy as possible for independent groups to use and/or extend the code for their purposes. POET represents a significant improvement over some previous models for planetary tidal evolution and so has many astrophysical applications. In this article, we describe and illustrate several key examples.

  16. Radiation: Balancing the record

    International Nuclear Information System (INIS)

    Mann, C.C.

    1994-01-01

    This article reviews the radioactivity experiments performed on humans during the cold war, and examines the ethics of the experiments. The radiation experiments can be broadly classified into three groups: researchers knowingly inflicted potential harm, using methods questionable even by the then-current standards; the investigations involved good work by any standards with appropriate safeguards taken; and a third group which falls between the other two, the experiments provided useful information but had ethical flaws. The article also examines the experiments in the light of changing knowledge and moral standards

  17. The History of Planetary Exploration Using Mass Spectrometers

    Science.gov (United States)

    Mahaffy, Paul R.

    2012-01-01

    At the Planetary Probe Workshop Dr. Paul Mahaffy will give a tutorial on the history of planetary exploration using mass spectrometers. He will give an introduction to the problems and solutions that arise in making in situ measurements at planetary targets using this instrument class.

  18. SPEX: The spectropolarimeter for planetary EXploration

    NARCIS (Netherlands)

    Snik, F.; Rietjens, J.H.H.; Harten, G. van; Stam, D.M.; Keller, C.U.; Smit, J.M.; Laan, E.C.; Verlaan, A.L.; Horst, R. ter; Navarro, R.; Wielinga, K.; Moon, S.G.; Voors, R.

    2010-01-01

    SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, compact instrument for spectropolarimetry, and in particular for detecting and characterizing aerosols in planetary atmospheres. With its ∼1-liter volume it is capable of full linear spectropolarimetry, without moving parts. The

  19. Balancing patient dose and image quality

    International Nuclear Information System (INIS)

    Martin, C.J.; Sutton, D.G.; Sharp, P.F.

    1999-01-01

    The formation of images in diagnostic radiology involves a complex interdependence of many factors. The ideal balance is to obtain an image which is adequate for the clinical purpose with the minimum radiation dose. Factors which affect radiation dose and image quality can be grouped under three headings; radiation quality, photon fluence and removal of scattered radiation. If optimal performance is to be achieved, it is necessary to understand how these factors influence image formation and affect radiation dose, and apply methodology for image quality and dose analysis at each stage in the development and use of X-ray equipment

  20. POET: Planetary Orbital Evolution due to Tides

    Science.gov (United States)

    Penev, Kaloyan

    2014-08-01

    POET (Planetary Orbital Evolution due to Tides) calculates the orbital evolution of a system consisting of a single star with a single planet in orbit under the influence of tides. The following effects are The evolutions of the semimajor axis of the orbit due to the tidal dissipation in the star and the angular momentum of the stellar convective envelope by the tidal coupling are taken into account. In addition, the evolution includes the transfer of angular momentum between the stellar convective and radiative zones, effect of the stellar evolution on the tidal dissipation efficiency, and stellar core and envelope spins and loss of stellar convective zone angular momentum to a magnetically launched wind. POET can be used out of the box, and can also be extended and modified.

  1. Troughs in Ice Sheets and Other Icy Deposits on Mars: Analysis of Their Radiative Balance

    Science.gov (United States)

    Fountain, A.; Kargel, J.; Lewis, K.; MacAyeal, D.; Pfeffer, T.; Zwally, H. J.

    2000-01-01

    It has long been known that groove-like structures in glaciers and ice sheets can trap more incoming solar radiation than is the case for a 'normal' flat, smooth surface. In this presentation, we shall describe the radiative regimes of typical scarps and troughs on icy surfaces of Mars, and suggest how these features originate and evolve through time. The basis of our analysis is the radiation balance model presented by Pfeffer and Bretherton. Their model considers the visible band radiation regime of a V-shaped groove on a terrestrial ice surface, and shows that absorbed energy can be enhanced by up to 50 percent for grooves with small opening angles and with typical polar values of the solar zenith angle. Our work extends this model by considering: (a) departures from V-shaped geometry, (b) both englacial and surficial dust and debris, and (c) the infrared spectrum. We apply the extended model to various features on the Martian surface, including the spiral-like scarps on the Northern and Southern ice sheets, the large-scale chasms (e.g., Chasm Borealis), and groove-like lineations on valley floors thought to be filled with mixtures of dust and icy substances. In conjunction with study of valley-closure experiments, we suggest that spiral-like scarps and chasms are stable features of the Martian climate regime. We also suggest that further study of scarps and chasms may shed light on the composition (i.e., relative proportions of water ice, carbon-dioxide ice and dust) of the Martian ice sheets and valley fills.

  2. PC 11: Symbiotic star or planetary nebulae?

    International Nuclear Information System (INIS)

    Gutierrez-Moreno, A.; Moreno, H.; Cortes, G.

    1987-01-01

    PC 11 is an object listed in Perek and Kohoutek (1967) Catalogue of Galactic Planetary Nebulae as PK 331 -5 0 1. Some authors suggest that it is not a planetary nebula, but that it has some characteristics (though not all) of symbiotic stars. We have made photographic, spectrophotometric and spectroscopic observations of PC 11. The analysis of the results suggests that it is a young planetary nebula. (Author)

  3. Precise Chemical Analyses of Planetary Surfaces

    Science.gov (United States)

    Kring, David; Schweitzer, Jeffrey; Meyer, Charles; Trombka, Jacob; Freund, Friedemann; Economou, Thanasis; Yen, Albert; Kim, Soon Sam; Treiman, Allan H.; Blake, David; hide

    1996-01-01

    We identify the chemical elements and element ratios that should be analyzed to address many of the issues identified by the Committee on Planetary and Lunar Exploration (COMPLEX). We determined that most of these issues require two sensitive instruments to analyze the necessary complement of elements. In addition, it is useful in many cases to use one instrument to analyze the outermost planetary surface (e.g. to determine weathering effects), while a second is used to analyze a subsurface volume of material (e.g., to determine the composition of unaltered planetary surface material). This dual approach to chemical analyses will also facilitate the calibration of orbital and/or Earth-based spectral observations of the planetary body. We determined that in many cases the scientific issues defined by COMPLEX can only be fully addressed with combined packages of instruments that would supplement the chemical data with mineralogic or visual information.

  4. Seasonal contrast in the surface energy balance of the Sahel

    Science.gov (United States)

    Miller, R. L.; Slingo, A.; Barnard, J. C.; Kassianov, E.

    2009-07-01

    Over much of the world, heating of the surface by sunlight is balanced predominately by evaporative cooling. However, at the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) in Niamey, Niger, evaporation makes a significant contribution to the surface energy balance only at the height of the rainy season, when precipitation has replenished the reservoir of soil moisture. The AMF was placed at Niamey from late 2005 to early 2007 to provide measurements of surface fluxes in coordination with geostationary satellite retrievals of radiative fluxes at the top of the atmosphere, as part of the RADAGAST experiment to calculate atmospheric radiative divergence. We use observations at the mobile facility to investigate how the surface adjusts to radiative forcing throughout the year. The surface response to solar heating varies with changes in atmospheric water vapor associated with the seasonal reversal of the West African monsoon, which modulates the greenhouse effect and the ability of the surface to radiate thermal energy directly to space. During the dry season, sunlight is balanced mainly by longwave radiation and the turbulent flux of sensible heat. The ability of longwave radiation to cool the surface drops after the onset of southwesterly surface winds at Niamey, when moist, oceanic air flows onshore, increasing local column moisture and atmospheric opacity. Following the onset of southwesterly flow, evaporation remains limited by the supply of moisture from precipitation. By the height of the rainy season, however, sufficient precipitation has accumulated that evaporation is controlled by incident sunlight, and radiative forcing of the surface is balanced comparably by the latent, sensible, and longwave fluxes. Evaporation increases with the leaf area index, suggesting that plants are a significant source of atmospheric moisture and may tap moisture stored beneath the surface that accumulated during a previous rainy season. Surface radiative forcing

  5. Influence of inhomogeneous surface heat capacity on the estimation of radiative response coefficients in a two-zone energy balance model

    Science.gov (United States)

    Park, Jungmin; Choi, Yong-Sang

    2018-04-01

    Observationally constrained values of the global radiative response coefficient are pivotal to assess the reliability of modeled climate feedbacks. A widely used approach is to measure transient global radiative imbalance related to surface temperature changes. However, in this approach, a potential error in the estimate of radiative response coefficients may arise from surface inhomogeneity in the climate system. We examined this issue theoretically using a simple two-zone energy balance model. Here, we dealt with the potential error by subtracting the prescribed radiative response coefficient from those calculated within the two-zone framework. Each zone was characterized by the different magnitude of the radiative response coefficient and the surface heat capacity, and the dynamical heat transport in the atmosphere between the zones was parameterized as a linear function of the temperature difference between the zones. Then, the model system was forced by randomly generated monthly varying forcing mimicking time-varying forcing like an observation. The repeated simulations showed that inhomogeneous surface heat capacity causes considerable miscalculation (down to -1.4 W m-2 K-1 equivalent to 31.3% of the prescribed value) in the global radiative response coefficient. Also, the dynamical heat transport reduced this miscalculation driven by inhomogeneity of surface heat capacity. Therefore, the estimation of radiative response coefficients using the surface temperature-radiation relation is appropriate for homogeneous surface areas least affected by the exterior.

  6. TESTS OF THE PLANETARY HYPOTHESIS FOR PTFO 8-8695b

    International Nuclear Information System (INIS)

    Yu, Liang; Winn, Joshua N.; Rappaport, Saul; Dai, Fei; Triaud, Amaury H. M. J.; Gillon, Michaël; Delrez, Laetitia; Jehin, Emmanuel; Lendl, Monika; Albrecht, Simon; Bieryla, Allyson; Holman, Matthew J.; Montet, Benjamin T.; Hillenbrand, Lynne; Howard, Andrew W.; Huang, Chelsea X.; Isaacson, Howard; Sanchis-Ojeda, Roberto; Muirhead, Philip

    2015-01-01

    The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted to be a consequence of orbital precession. We observed 28 fading events spread over several years and did not see the expected changes. Instead, we found that the fading events are not strictly periodic. Second, we attempted to detect the planet's radiation, based on infrared observations spanning the predicted times of occultations. We ruled out a signal of the expected amplitude. Third, we attempted to detect the Rossiter–McLaughlin effect by performing high-resolution spectroscopy throughout a fading event. No effect was seen at the expected level, ruling out most (but not all) possible orientations for the hypothetical planetary orbit. Our spectroscopy also revealed strong, time-variable, high-velocity Hα and Ca H and K emission features. All these observations cast doubt on the planetary hypothesis, and suggest instead that the fading events represent starspots, eclipses by circumstellar dust, or occultations of an accretion hotspot

  7. Radiation balance in the sweet sorghum crop

    International Nuclear Information System (INIS)

    Assis, F.N. de; Mendez, M.E.G.; Martins, S.R.; Verona, L.A.

    1987-01-01

    The fluxes of incident solar radiation, reflected and net radiation were measured during the growing cicle of two fields of sweet sorghum (Sorghum bicolor L.), cus. BR-501 and BR-503, maintained under convenient irrigation level. Resultant data allowed to estimate the crop albedo as well as the estimates of Rn. (M.A.C.) [pt

  8. Studies of planetary boundary layer by infrared thermal imagery

    Energy Technology Data Exchange (ETDEWEB)

    Albina, Bogdan; Dimitriu, Dan Gheorghe, E-mail: dimitriu@uaic.ro; Gurlui, Silviu Octavian, E-mail: dimitriu@uaic.ro [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi (Romania); Cazacu, Marius Mihai [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi, Romania and Department of Physics, Gheorghe Asachi Technical University of Iasi, 59A Mangeron Blvd., 700 (Romania); Timofte, Adrian [Alexandru Ioan Cuza University of Iasi, Faculty of Physics, Atmosphere Optics, Spectroscopy and Lasers Laboratory, 11 Carol I Blvd., 700506 Iasi, Romania and National Meteorological Administration, Regional Forecast Center Bacau, 1 Cuza Voda Str., 60 (Romania)

    2014-11-24

    The IR camera is a relatively novel device for remote sensing of atmospheric thermal processes from the Planetary Boundary Layer (PBL) based on measurements of the infrared radiation. Infrared radiation is energy radiated by the motion of atoms and molecules on the surface of aerosols, when their temperature is more than absolute zero. The IR camera measures directly the intensity of radiation emitted by aerosols which is converted by an imaging sensor into an electric signal, resulting a thermal image. Every image pixel that corresponds to a specific radiance is pre-processed to identify the brightness temperature. The thermal infrared imaging radiometer used in this study, NicAir, is a precision radiometer developed by Prata et al. The device was calibrated for the temperature range of 270–320 K and using a calibration table along with image processing software, important information about variations in temperature can be extracted from acquired IR images. The PBL is the lowest layer of the troposphere where the atmosphere interacts with the ground surfaces. The importance of PBL lies in the fact that it provides a finite but varying volume in which pollutants can disperse. The aim of this paper is to analyze the PBL altitude and thickness variations over Iasi region using the IR imaging camera as well as its behavior from day to night and thermal processes occurring in PBL.

  9. Visualizing NASA's Planetary Data with Google Earth

    Science.gov (United States)

    Beyer, R. A.; Hancher, M. D.; Broxton, M.; Weiss-Malik, M.; Gorelick, N.; Kolb, E.

    2008-12-01

    There is a vast store of planetary geospatial data that has been collected by NASA but is difficult to access and visualize. As a 3D geospatial browser, the Google Earth client is one way to visualize planetary data. KML imagery super-overlays enable us to create a non-Earth planetary globe within Google Earth, and conversion of planetary meta-data allows display of the footprint locations of various higher-resolution data sets. Once our group, or any group, performs these data conversions the KML can be made available on the Web, where anyone can download it and begin using it in Google Earth (or any other geospatial browser), just like a Web page. Lucian Plesea at JPL offers several KML basemaps (MDIM, colorized MDIM, MOC composite, THEMIS day time infrared, and both grayscale and colorized MOLA). We have created TES Thermal Inertia maps, and a THEMIS night time infrared overlay, as well. Many data sets for Mars have already been converted to KML. We provide coverage polygons overlaid on the globe, whose icons can be clicked on and lead to the full PDS data URL. We have built coverage maps for the following data sets: MOC narrow angle, HRSC imagery and DTMs, SHARAD tracks, CTX, and HiRISE. The CRISM team is working on providing their coverage data via publicly-accessible KML. The MSL landing site process is also providing data for potential landing sites via KML. The Google Earth client and KML allow anyone to contribute data for everyone to see via the Web. The Earth sciences community is already utilizing KML and Google Earth in a variety of ways as a geospatial browser, and we hope that the planetary sciences community will do the same. Using this paradigm for sharing geospatial data will not only enable planetary scientists to more easily build and share data within the scientific community, but will also provide an easy platform for public outreach and education efforts, and will easily allow anyone to layer geospatial information on top of planetary data

  10. Ultraviolet spectroscopy of planetary nebulae in the Magellanic Clouds

    International Nuclear Information System (INIS)

    Maran, S.P.; Aller, L.H.; Gull, T.R.; Stecher, T.P.

    1982-01-01

    Ultraviolet spectra of three high excitation planetary nebulae in the Magellanic Clouds (LMC P40, SMC N2, SMC N5) were obtained with the International Ultraviolet Explorer. The results are analyzed together with new visual wavelength spectrophotometry of LMC P40 and published data on SMC N2 and SMC N5 to investigate chemical composition and in particular to make the first reliable estimates of the carbon abundance in extragalactic planetary nebulae. Although carbon is at most only slightly less abundant in the LMC and SMC planetary nebulae than in galactic planetaries, it is almost 40 times more abundant in the SMC planetaries than in the SMC interstellar medium, and is about 6 times more abundant in the LMC planetary than in the LMC interstellar medium. According to our limited sample, the net result of carbon synthesis and convective dredgeup in the progenitors of planetary nebulae, as reflected in the nebular carbon abundance, is roughly the same in the Galaxy, the LMC, and the SMC

  11. The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres.

    Science.gov (United States)

    Goldblatt, Colin; Watson, Andrew J

    2012-09-13

    The ultimate climate emergency is a 'runaway greenhouse': a hot and water-vapour-rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only after the surface reaches approximately 1400 K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that the Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here, we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon dioxide to the atmosphere. However, our understanding of the dynamics, thermodynamics, radiative transfer and cloud physics of hot and steamy atmospheres is weak. We cannot therefore completely rule out the possibility that human actions might cause a transition, if not to full runaway, then at least to a much warmer climate state than the present one. High climate sensitivity might provide a warning. If we, or more likely our remote descendants, are threatened with a runaway greenhouse, then geoengineering to reflect sunlight might be life's only hope. Injecting reflective aerosols into the stratosphere would be too short-lived, and even sunshades in space might require excessive maintenance. In the distant future, modifying Earth's orbit might provide a sustainable solution. The runaway greenhouse also remains relevant in planetary sciences and astrobiology: as extrasolar planets smaller and nearer to their stars are detected, some will be in

  12. Planetary engineering

    Science.gov (United States)

    Pollack, James B.; Sagan, Carl

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  13. Planetary engineering

    Science.gov (United States)

    Pollack, James B.; Sagan, Carl

    1991-01-01

    Assuming commercial fusion power, heavy lift vehicles and major advances in genetic engineering, the authors survey possible late-21st century methods of working major transformations in planetary environments. Much more Earthlike climates may be produced on Mars by generating low freezing point greenhouse gases from indigenous materials; on Venus by biological conversion of CO2 to graphite, by canceling the greenhouse effect with high-altitude absorbing fine particles, or by a sunshield at the first Lagrangian point; and on Titan by greenhouses and/or fusion warming. However, in our present state of ignorance we cannot guarantee a stable endstate or exclude unanticipated climatic feedbacks or other unintended consequences. Moreover, as the authors illustrate by several examples, many conceivable modes of planetary engineering are so wasteful of scarce solar system resources and so destructive of important scientific information as to raise profound ethical issues, even if they were economically feasible, which they are not. Global warming on Earth may lead to calls for mitigation by planetary engineering, e.g., emplacement and replenishment of anti-greenhouse layers at high altitudes, or sunshields in space. But here especially we must be concerned about precision, stability, and inadvertent side-effects. The safest and most cost-effective means of countering global warming - beyond, e.g., improved energy efficiency, CFC bans and alternative energy sources - is the continuing reforestation of approximately 2 times 107 sq km of the Earth's surface. This can be accomplished with present technology and probably at the least cost.

  14. The Making of a Pre-Planetary Nebula

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    The gas expelled by dying stars gets twisted into intricate shapes and patterns as nebulae form. Now a team of researchers might have some answers about how this happens.Whats a Pre-Planetary Nebula?This H-R diagram for the globular cluster M5 shows where AGB stars lie: they are represented by blue markers here. The AGB is one of the final stages in a low- to intermediate-mass stars lifetime. [Lithopsian]When a low- to intermediate-mass star approaches the end of its lifetime, it moves onto the Asymptotic Giant Branch (AGB) in the Herzsprung-Russell diagram. As the star exhausts its fuel here, it shrugs off its outer layers. These layers of gas then encase the stars core, which is not yet hot enough to ionize the gas and cause it to glow.Instead, during this time the gas is relatively cool and dark, faintly reflecting light from the star and emitting only very dim infrared emission of its own. At this stage, the gas represents a pre-planetary nebula. Only later when the stellar core contracts enough to heat up and emit ionizing radiation does the nebula begin to properly glow, at which point it qualifies as a full planetary nebula.Images of OH231 in optical light (top) and 12CO (bottom) taken from the literature. [See Balick et al. 2017 for full credit]Unexpected ShapesPre-planetary nebulae are a very short-lived evolutionary stage, so weve observed only a few hundred of them which has left many unanswered questions about these objects.One particular mystery is that of their shapes: if these nebulae are formed by stars expelling their outer layers, we would naively expect them to be simple spherical shells and yet we observe pre-planetary nebulae to have intricate shapes and patterns. How does the star create these asymmetric shapes? A team of scientists led by Bruce Balick (University of Washington, Seattle) has now used simulations to address this question.Injecting MassBalick and collaborators use 3D hydrodynamic simulations to model one particular pre-planetary

  15. Planetary Geomorphology.

    Science.gov (United States)

    Baker, Victor R.

    1984-01-01

    Discusses various topics related to planetary geomorphology, including: research techniques; such geomorphic processes as impact, volcanic, degradational, eolian, and hillslope/mass movement processes; and channels and valleys. Indicates that the subject should be taught as a series of scientific questions rather than scientific results of…

  16. Electrostatic Phenomena on Planetary Surfaces

    Science.gov (United States)

    Calle, Carlos I.

    2017-02-01

    The diverse planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near planetary surfaces. The desire to understand the electrostatic environments of planetary surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.

  17. Pioneer 10/11 data analysis of the trapped radiation experiment

    Science.gov (United States)

    Fillius, W.

    1982-01-01

    The data handling operations and the database produced by the Trapped Radiation Experiment on the NASA Pioneer 10 and 11 spacecraft are outlined. In situ measurements of trapped radiation at both Jupiter and Saturn, the extension of cosmic ray observations to the outer heliosphere, the presence of Jovian electrons in interplanetary space, analyses of the interaction between planetary satellites and the trapped radiation that engulfs them, and further investigations of the radiation enviroments of both planets are reported.

  18. Significant achievements in the planetary geology program. Final report

    International Nuclear Information System (INIS)

    Head, J.W.

    1978-12-01

    Developments reported at a meeting of principal investigators for NASA's planetology geology program are summarized. Topics covered include the following: constraints on solar system formation; asteriods, comets, and satellites; constraints on planetary interiors; volatiles and regoliths; instrument development techniques; planetary cartography; geological and geochemical constraints on planetary evolution; fluvial processes and channel formation; volcanic processes; Eolian processes; radar studies of planetary surfaces; cratering as a process, landform, and dating method; and the Tharsis region of Mars. Activities at a planetary geology field conference on Eolian processes are reported and techniques recommended for the presentation and analysis of crater size-frequency data are included

  19. Rocky Planetary Debris Around Young WDs

    Science.gov (United States)

    Gaensicke, B.

    2014-04-01

    The vast majority of all known planet host stars, including the Sun, will eventually evolve into red giants and finally end their lives as white dwarfs: extremely dense Earth-sized stellar embers. Only close-in planets will be devoured during the red-giant phase. In the solar system, Mars, the asteroid belt, and all the giant planets will escape evaporation, and the same is true for many of the known exo-planets. It is hence certain that a significant fraction of the known white dwarfs were once host stars to planets, and it is very likely that many of them still have remnants of planetary systems. The detection of metals in the atmospheres of white dwarfs is the unmistakable signpost of such evolved planetary systems. The strong surface gravity of white dwarfs causes metals to sink out of the atmosphere on time-scales much shorter than their cooling ages, leading unavoidably to pristine H/He atmospheres. Therefore any metals detected in the atmosphere of a white dwarf imply recent or ongoing accretion of planetary debris. In fact, planetary debris is also detected as circumstellar dust and gas around a number of white dwarfs. These debris disks are formed from the tidal disruption of asteroids or Kuiper belt-like objects, stirred up by left-over planets, and are subsequently accreted onto the white dwarf, imprinting their abundance pattern into its atmosphere. Determining the photospheric abundances of debris-polluted white dwarfs is hence entirely analogue to the use of meteorites, "rocks that fell from the sky", for measuring the abundances of planetary material in the solar system. I will briefly review this new field of exo-planet science, and then focus on the results of a large, unbiased COS snapshot survey of relatively young ( 20-100Myr) white dwarfs that we carried out in Cycle 18/19. * At least 30% of all white dwarfs in our sample are accreting planetary debris, and that fraction may be as high as 50%. * In most cases where debris pollution is detected

  20. Planetary Vital Signs

    Science.gov (United States)

    Kennel, Charles; Briggs, Stephen; Victor, David

    2016-07-01

    The climate is beginning to behave in unusual ways. The global temperature reached unprecedented highs in 2015 and 2016, which led climatologists to predict an enormous El Nino that would cure California's record drought. It did not happen the way they expected. That tells us just how unreliable temperature has become as an indicator of important aspects of climate change. The world needs to go beyond global temperature to a set of planetary vital signs. Politicians should not over focus policy on one indicator. They need to look at the balance of evidence. A coalition of scientists and policy makers should start to develop vital signs at once, since they should be ready at the entry into force of the Paris Agreement in 2020. But vital signs are only the beginning. The world needs to learn how to use the vast knowledge we will be acquiring about climate change and its impacts. Is it not time to use all the tools at hand- observations from space and ground networks; demographic, economic and societal measures; big data statistical techniques; and numerical models-to inform politicians, managers, and the public of the evolving risks of climate change at global, regional, and local scales? Should we not think in advance of an always-on social and information network that provides decision-ready knowledge to those who hold the responsibility to act, wherever they are, at times of their choosing?

  1. Lunar and Planetary Science XXXV: Origin of Planetary Systems

    Science.gov (United States)

    2004-01-01

    The session titled Origin of Planetary Systems" included the following reports:Convective Cooling of Protoplanetary Disks and Rapid Giant Planet Formation; When Push Comes to Shove: Gap-opening, Disk Clearing and the In Situ Formation of Giant Planets; Late Injection of Radionuclides into Solar Nebula Analogs in Orion; Growth of Dust Particles and Accumulation of Centimeter-sized Objects in the Vicinity of a Pressure enhanced Region of a Solar Nebula; Fast, Repeatable Clumping of Solid Particles in Microgravity ; Chondrule Formation by Current Sheets in Protoplanetary Disks; Radial Migration of Phyllosilicates in the Solar Nebula; Accretion of the Outer Planets: Oligarchy or Monarchy?; Resonant Capture of Irregular Satellites by a Protoplanet ; On the Final Mass of Giant Planets ; Predicting the Atmospheric Composition of Extrasolar Giant Planets; Overturn of Unstably Stratified Fluids: Implications for the Early Evolution of Planetary Mantles; and The Evolution of an Impact-generated Partially-vaporized Circumplanetary Disk.

  2. SMALL PLANETARY SATELLITE COLORS V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is intended to include published colors of small planetary satellites published up through December 2003. Small planetary satellites are defined as all...

  3. The Formation of a Planetary Nebula.

    Science.gov (United States)

    Harpaz, Amos

    1991-01-01

    Proposes a scenario to describe the formation of a planetary nebula, a cloud of gas surrounding a very hot compact star. Describes the nature of a planetary nebula, the number observed to date in the Milky Way Galaxy, and the results of research on a specific nebula. (MDH)

  4. Modeling, Testing, and Characteristic Analysis of a Planetary Flywheel Inerter

    Directory of Open Access Journals (Sweden)

    Zheng Ge

    2018-01-01

    Full Text Available We propose the planetary flywheel inerter, which is a new type of ball screw inerter. A planetary flywheel consists of several planetary gears mounted on a flywheel bracket. When the flywheel bracket is driven by a screw and rotating, each planetary gear meshing with an outer ring gear generates a compound motion composed of revolution and rotation. Theoretical analysis shows that the output force of the planetary flywheel inerter is proportional to the relative acceleration of one terminal of the inerter to the other. Optimizing the gear ratio of the planetary gears to the ring gear allows the planetary flywheel to be lighter than its traditional counterpart, without any loss on the inertance. According to the structure of the planetary flywheel inerter, nonlinear factors of the inerter are analyzed, and a nonlinear dynamical model of the inerter is established. Then the parameters in the model are identified and the accuracy of the model is validated by experiment. Theoretical analysis and experimental data show that the dynamical characteristics of a planetary flywheel inerter and those of a traditional flywheel inerter are basically the same. It is concluded that a planetary flywheel can completely replace a traditional flywheel, making the inerter lighter.

  5. Future planetary X-ray and gamma-ray remote sensing system and in situ requirements for room temperature solid state detectors

    CERN Document Server

    Trombka, J I; Starr, R; Clark, P E; Floyd, S R

    1999-01-01

    X-Ray and gamma-ray remote sensing observations find important applications in the study of the development of the planets. Orbital measurements can be carried out on solar-system bodies whose atmospheres and trapped radiation environments do not interfere significantly with the emissions. Elemental compositions can be inferred from observations of these line emissions. Future planetary missions also will involve landing both stationery and roving probes on planetary surfaces. Both X-ray and gamma-ray spectrometers will be used for performing elemental analysis of surface samples. These future planetary missions will impose a number of constraints: the flight instruments must be significantly reduced in weight from those previously flown; for many missions, gravity assist will be required, greatly increasing mission duration, resulting in the passage of several years before the first scientific measurement of a solar system body. The detector systems must operate reliably after years of cosmic-ray irradiation...

  6. Planetary Habitability

    Science.gov (United States)

    Kasting, James F.

    1997-01-01

    This grant was entitled 'Planetary Habitability' and the work performed under it related to elucidating the conditions that lead to habitable, i.e. Earth-like, planets. Below are listed publications for the past two and a half years that came out of this work. The main thrusts of the research involved: (1) showing under what conditions atmospheric O2 and O3 can be considered as evidence for life on a planet's surface; (2) determining whether CH4 may have played a role in warming early Mars; (3) studying the effect of varying UV levels on Earth-like planets around different types of stars to see whether this would pose a threat to habitability; and (4) studying the effect of chaotic obliquity variations on planetary climates and determining whether planets that experienced such variations might still be habitable. Several of these topics involve ongoing research that has been carried out under a new grant number, but which continues to be funded by NASA's Exobiology program.

  7. Planetary geology

    CERN Document Server

    Gasselt, Stephan

    2018-01-01

    This book provides an up-to-date interdisciplinary geoscience-focused overview of solid solar system bodies and their evolution, based on the comparative description of processes acting on them. Planetary research today is a strongly multidisciplinary endeavor with efforts coming from engineering and natural sciences. Key focal areas of study are the solid surfaces found in our Solar System. Some have a direct interaction with the interplanetary medium and others have dynamic atmospheres. In any of those cases, the geological records of those surfaces (and sub-surfaces) are key to understanding the Solar System as a whole: its evolution and the planetary perspective of our own planet. This book has a modular structure and is divided into 4 sections comprising 15 chapters in total. Each section builds upon the previous one but is also self-standing. The sections are:  Methods and tools Processes and Sources  Integration and Geological Syntheses Frontiers The latter covers the far-reaching broad topics of exo...

  8. From red giants to planetary nebulae: Asymmetries, dust, and polarization

    International Nuclear Information System (INIS)

    Johnson, J.J.

    1990-01-01

    In order to investigate the development of aspherical planetary nebulae, polarimetry was obtained for a group of planetary nebulae and for objects that will evolve into planetary nebulae, i.e., red giants, late asymptotic giant branch (AGB) objects, proto-planetary nebulae, and young planetary nebulae. To study the dust around the objects in our sample, we also used data from the Infrared Astronomy Satellite (IRAS) mission. The youngest objects in our survey, red giants, had the hottest dust temperatures while planetary nebulae had the coolest. Most of the objects were intrinsically polarized, including the red giants. This indicated that the circumstellar dust shells of these objects were aspherical. Both carbon- and oxygen-rich objects could be intrinsically polarized. The intrinsic polarizations of a sample of our objects were modeled using an ellipsoidal circumstellar dust shell. The findings of this study suggest that the asphericities that lead to an aspherical planetary nebula originate when a red giant begins to undergo mass loss. The polarization and thus the asphericity as the star evolves, with both reaching a maximum during the proto-planetary nebula stage. The circumstellar dust shell will dissipate after the proto-planetary nebulae stage since no new material is being added. The polarization of planetary nebulae will thus be low. In the most evolved planetary nebulae, the dust has either been destroyed or dissipated into the interstellar medium. In these objects no polarization was observed

  9. The influence of diffusion and of reabsorption of radiation on the particle and energy balance of an infinitely long quasi-cylindrical discharge in hydrogen gas

    International Nuclear Information System (INIS)

    Goedheer, W.J.

    1978-09-01

    A numerical study of the pressure and temperature profiles of an infinitely long quasi-cylindrical discharge in hydrogen gas is presented. In particular the influence of the diffusion of atoms in the ground state and the reabsorption of Lyman-α and Lyman-β radiation on both the particle balance and the energy balance of the discharge is studied. Because the transport of the charged particles is corrected for toroidal effects in the regime of high collisionality which is present in the discharge, the model is quasi-cylindrical. The results obtained show an increase of the neutral density on the axis and of the ion and electron density near the wall of the discharge, as compared with earlier calculations in which both diffusion and reabsorption of radiation were neglected. The results are in agreement with measurements in the 'Ringboog' experiment. (Auth.)

  10. Red giants as precursors of planetary nebulae

    International Nuclear Information System (INIS)

    Renzini, A.

    1981-01-01

    It is generally accepted that Planetary Nebulae are produced by asymptotic giant-branch stars. Therefore, several properties of planetary nebulae are discussed in the framework of the current theory of stellar evolution. (Auth.)

  11. ORBSIM- ESTIMATING GEOPHYSICAL MODEL PARAMETERS FROM PLANETARY GRAVITY DATA

    Science.gov (United States)

    Sjogren, W. L.

    1994-01-01

    The ORBSIM program was developed for the accurate extraction of geophysical model parameters from Doppler radio tracking data acquired from orbiting planetary spacecraft. The model of the proposed planetary structure is used in a numerical integration of the spacecraft along simulated trajectories around the primary body. Using line of sight (LOS) Doppler residuals, ORBSIM applies fast and efficient modelling and optimization procedures which avoid the traditional complex dynamic reduction of data. ORBSIM produces quantitative geophysical results such as size, depth, and mass. ORBSIM has been used extensively to investigate topographic features on the Moon, Mars, and Venus. The program has proven particulary suitable for modelling gravitational anomalies and mascons. The basic observable for spacecraft-based gravity data is the Doppler frequency shift of a transponded radio signal. The time derivative of this signal carries information regarding the gravity field acting on the spacecraft in the LOS direction (the LOS direction being the path between the spacecraft and the receiving station, either Earth or another satellite). There are many dynamic factors taken into account: earth rotation, solar radiation, acceleration from planetary bodies, tracking station time and location adjustments, etc. The actual trajectories of the spacecraft are simulated using least squares fitted to conic motion. The theoretical Doppler readings from the simulated orbits are compared to actual Doppler observations and another least squares adjustment is made. ORBSIM has three modes of operation: trajectory simulation, optimization, and gravity modelling. In all cases, an initial gravity model of curved and/or flat disks, harmonics, and/or a force table are required input. ORBSIM is written in FORTRAN 77 for batch execution and has been implemented on a DEC VAX 11/780 computer operating under VMS. This program was released in 1985.

  12. Blue Marble Matches: Using Earth for Planetary Comparisons

    Science.gov (United States)

    Graff, Paige Valderrama

    2009-01-01

    Goal: This activity is designed to introduce students to geologic processes on Earth and model how scientists use Earth to gain a better understanding of other planetary bodies in the solar system. Objectives: Students will: 1. Identify common descriptor characteristics used by scientists to describe geologic features in images. 2. Identify geologic features and how they form on Earth. 3. Create a list of defining/distinguishing characteristics of geologic features 4. Identify geologic features in images of other planetary bodies. 5. List observations and interpretations about planetary body comparisons. 6. Create summary statements about planetary body comparisons.

  13. THE REGULARITIES OF THE SPACE-TEMPORAL DISTRIBUTION OF THE RADIATION BALANCE OF THE UNDERLYING SURFACE IN ARAKS BASIN ON MOUNTAINOUS TERRITORY OF THE REPUBLIC OF ARMENIA

    Directory of Open Access Journals (Sweden)

    V. G. Margaryan

    2017-12-01

    Full Text Available The regularities of the space-temporal distribution of the radiation balance of the underlying surface for the conditions of the mountainous territory of the Republic of Armenia were discussed and analyzed.

  14. Summary of the Third International Planetary Dunes Workshop: remote sensing and image analysis of planetary dunes

    Science.gov (United States)

    Fenton, Lori K.; Hayward, Rosalyn K.; Horgan, Briony H.N.; Rubin, David M.; Titus, Timothy N.; Bishop, Mark A.; Burr, Devon M.; Chojnacki, Matthew; Dinwiddie, Cynthia L.; Kerber, Laura; Gall, Alice Le; Michaels, Timothy I.; Neakrase, Lynn D.V.; Newman, Claire E.; Tirsch, Daniela; Yizhaq, Hezi; Zimbelman, James R.

    2013-01-01

    The Third International Planetary Dunes Workshop took place in Flagstaff, AZ, USA during June 12–15, 2012. This meeting brought together a diverse group of researchers to discuss recent advances in terrestrial and planetary research on aeolian bedforms. The workshop included two and a half days of oral and poster presentations, as well as one formal (and one informal) full-day field trip. Similar to its predecessors, the presented work provided new insight on the morphology, dynamics, composition, and origin of aeolian bedforms on Venus, Earth, Mars, and Titan, with some intriguing speculation about potential aeolian processes on Triton (a satellite of Neptune) and Pluto. Major advancements since the previous International Planetary Dunes Workshop include the introduction of several new data analysis and numerical tools and utilization of low-cost field instruments (most notably the time-lapse camera). Most presentations represented advancement towards research priorities identified in both of the prior two workshops, although some previously recommended research approaches were not discussed. In addition, this workshop provided a forum for participants to discuss the uncertain future of the Planetary Aeolian Laboratory; subsequent actions taken as a result of the decisions made during the workshop may lead to an expansion of funding opportunities to use the facilities, as well as other improvements. The interactions during this workshop contributed to the success of the Third International Planetary Dunes Workshop, further developing our understanding of aeolian processes on the aeolian worlds of the Solar System.

  15. Mars Technology Program Planetary Protection Technology Development

    Science.gov (United States)

    Lin, Ying

    2006-01-01

    The objectives of the NASA Planetary Protection program are to preserve biological and organic conditions of solar-system bodies for future scientific exploration and to protect the Earth from potential hazardous extraterrestrial contamination. As the exploration of solar system continues, NASA remains committed to the implementation of planetary protection policy and regulations. To fulfill this commitment, the Mars Technology Program (MTP) has invested in a portfolio of tasks for developing necessary technologies to meet planetary protection requirements for the next decade missions.

  16. Opportunities and trade-offs of biomass based negative emissions within planetary boundaries

    Science.gov (United States)

    Heck, Vera; Gerten, Dieter; Lucht, Wolfgang

    2017-04-01

    The Paris Agreement requires "a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of the century" (UNFCCC, 2015). Without a full decarbonization of the energy and land use sector until the second half of this century, negative emission technologies (NETs) are required to achieve net zero greenhouse gas emissions. Integrated assessment studies indicate that bioenergy with carbon capture and storage (BECCS), a land based NET, has the potential to contribute substantially to balancing anthropogenic fossil fuel emissions. However, significant negative emission potentials from BECCS require substantial biomass potentials, which can only be achieved by intensively managed (fertilized and irrigated) large-scale biomass plantations. Additional to direct trade-offs of land and water availability, the implementation of large-scale biomass plantations implies major restructuring of the land surface on top of existing land use and would be accompanied by indirect trade-offs such as changes in moisture and energy fluxes. In the context of the planetary boundaries framework as proposed by Rockström et al. (2009), BECCS might contribute to reduce the transgression of the planetary boundary (PB) for climate change, but would most likely steer the Earth system closer to the PB for freshwater use and lead to further transgression of the PBs for land system change, biosphere integrity and biogeochemical flows. This presentation will investigate the opportunities of second generation biomass potentials within the safe operating space for humanity and highlight the multidimensional trade-offs between biomass potentials for BECCS in relation to the PBs. Scenarios of land availability for biomass plantations and land based carbon sequestration were developed with a spatially explicit multi-criterial optimization framework, considering the precautionary need to stay within the safe operating space vis-à-vis the need to

  17. Planetary optical and infrared imaging

    International Nuclear Information System (INIS)

    Terrile, R.J.

    1988-01-01

    The purpose of this investigation is to obtain and analyze high spatial resolution charge coupled device (CCD) coronagraphic images of extra-solar planetary material and solar system objects. These data will provide information on the distribution of planetary and proto-planetary material around nearby stars leading to a better understanding of the origin and evolution of the solar system. Imaging within our solar system will provide information on the current cloud configurations on the outer planets, search for new objects around the outer planets, and provide direct support for Voyager, Galileo, and CRAF by imaging material around asteroids and clouds on Neptune. Over the last year this program acquired multispectral and polarization images of the disk of material around the nearby star Beta Pictoris. This material is believed to be associated with the formation of planets and provides a first look at a planetary system much younger than our own. Preliminary color and polarization data suggest that the material is very low albedo and similar to dark outer solar system carbon rich material. A coronagraphic search for other systems is underway and has already examined over 100 nearby stars. Coronagraphic imaging provided the first clear look at the rings of Uranus and albedo limits for the ring arcs around Neptune

  18. NASA's Planetary Science Missions and Participations

    Science.gov (United States)

    Daou, Doris; Green, James L.

    2017-04-01

    NASA's Planetary Science Division (PSD) and space agencies around the world are collaborating on an extensive array of missions exploring our solar system. Planetary science missions are conducted by some of the most sophisticated robots ever built. International collaboration is an essential part of what we do. NASA has always encouraged international participation on our missions both strategic (ie: Mars 2020) and competitive (ie: Discovery and New Frontiers) and other Space Agencies have reciprocated and invited NASA investigators to participate in their missions. NASA PSD has partnerships with virtually every major space agency. For example, NASA has had a long and very fruitful collaboration with ESA. ESA has been involved in the Cassini mission and, currently, NASA funded scientists are involved in the Rosetta mission (3 full instruments, part of another), BepiColombo mission (1 instrument in the Italian Space Agency's instrument suite), and the Jupiter Icy Moon Explorer mission (1 instrument and parts of two others). In concert with ESA's Mars missions NASA has an instrument on the Mars Express mission, the orbit-ground communications package on the Trace Gas Orbiter (launched in March 2016) and part of the DLR/Mars Organic Molecule Analyzer instruments going onboard the ExoMars Rover (to be launched in 2018). NASA's Planetary Science Division has continuously provided its U.S. planetary science community with opportunities to include international participation on NASA missions too. For example, NASA's Discovery and New Frontiers Programs provide U.S. scientists the opportunity to assemble international teams and design exciting, focused planetary science investigations that would deepen the knowledge of our Solar System. The PSD put out an international call for instruments on the Mars 2020 mission. This procurement led to the selection of Spain and Norway scientist leading two instruments and French scientists providing a significant portion of another

  19. The Planetary Data System Web Catalog Interface--Another Use of the Planetary Data System Data Model

    Science.gov (United States)

    Hughes, S.; Bernath, A.

    1995-01-01

    The Planetary Data System Data Model consists of a set of standardized descriptions of entities within the Planetary Science Community. These can be real entities in the space exploration domain such as spacecraft, instruments, and targets; conceptual entities such as data sets, archive volumes, and data dictionaries; or the archive data products such as individual images, spectrum, series, and qubes.

  20. Getting the balance right

    International Nuclear Information System (INIS)

    1987-01-01

    This 8 page leaflet is published by the Nuclear Electricity Information Group (NEIG) which is made up of eight different bodies working within the nuclear industry. It aims to present a balanced outline of the facts needed to form an opinion about energy policy in the UK. It looks at the price of electricity, other sources of electricity, (oil and coal, solar power, wind power, water power), safety in the nuclear industry, nuclear waste disposal and risks from radiation. The NEIG is in favour of a balanced energy programme with nuclear energy being only a part of the overall scheme. (U.K.)

  1. Effects of mass and metallicity upon planetary nebula formation

    International Nuclear Information System (INIS)

    Papp, K.A.; Purton, C.R.; Kwok, S.

    1983-01-01

    We construct a parameterized function which describes the possible dependence of planetary nebula formation upon metal abundance and stellar mass. Data on galaxies in the Local Group compared with predictions made from the parameterized function indicate that heavy element abundance is the principal agent influencing the formation of planetary nebulae; stars which are rich in heavy elements are the progenitors of planetary nebulae. Our analysis, when compared with the observations, argues for a modest degree of pre-enrichment in a few of the sample galaxies. The heavy element dependence of planetary nebula formation also accounts for the deficit of planetary nebula in the nuclei of NGC 221 and NGC 224, and in the bulge of our Galaxy

  2. Engaging Audiences in Planetary Science Through Visualizations

    Science.gov (United States)

    Shupla, C. B.; Mason, T.; Peticolas, L. M.; Hauck, K.

    2017-12-01

    One way to share compelling stories is through visuals. The Lunar and Planetary Institute (LPI), in collaboration with Laboratory for Atmospheric and Space Physics (LASP) and Space Science Laboratory at the University of California, Berkeley, has been working with planetary scientists to reach and engage audiences in their research through the use of visualizations. We will share how images and animations have been used in multiple mediums, including the planetarium, Science on a Sphere, the hyperwall, and within apps. Our objectives are to provide a tool that planetary scientists can use to tell their stories, as well as to increase audience awareness of and interest in planetary science. While scientists are involved in the selection of topics and the development of the visuals, LPI and partners seek to increase the planetary science community's awareness of these resources and their ability to incorporate them into their own public engagement efforts. This presentation will share our own resources and efforts, as well as the input received from scientists on how education and public engagement teams can best assist them in developing and using these resources, and disseminating them to both scientists and to informal science education venues.

  3. DESIGN FOR A BI-PLANETARY GEAR TRAIN

    Directory of Open Access Journals (Sweden)

    Józef DREWNIAK

    2016-06-01

    Full Text Available The article presents the design for a bi-planetary gear train. The project description is supplemented with calculations of kinematics, statics and meshing efficiency of the gear wheels included in the gear train. Excluded are calculations of strength and geometry of gears, shaft and rolling bearing, since they are similar to classical calculations for planetary gears. An assembly drawing in 2D and assembly drawings in 3D of the designed bi-planetary gear train are also shown. This gear train will form the main element of the research in hand.

  4. Robotic vehicles for planetary exploration

    Science.gov (United States)

    Wilcox, Brian; Matthies, Larry; Gennery, Donald; Cooper, Brian; Nguyen, Tam; Litwin, Todd; Mishkin, Andrew; Stone, Henry

    1992-01-01

    A program to develop planetary rover technology is underway at the Jet Propulsion Laboratory (JPL) under sponsorship of the National Aeronautics and Space Administration. Developmental systems with the necessary sensing, computing, power, and mobility resources to demonstrate realistic forms of control for various missions have been developed, and initial testing has been completed. These testbed systems and the associated navigation techniques used are described. Particular emphasis is placed on three technologies: Computer-Aided Remote Driving (CARD), Semiautonomous Navigation (SAN), and behavior control. It is concluded that, through the development and evaluation of such technologies, research at JPL has expanded the set of viable planetary rover mission possibilities beyond the limits of remotely teleoperated systems such as Lunakhod. These are potentially applicable to exploration of all the solid planetary surfaces in the solar system, including Mars, Venus, and the moons of the gas giant planets.

  5. VARIATIONAL PRINCIPLE FOR PLANETARY INTERIORS

    International Nuclear Information System (INIS)

    Zeng, Li; Jacobsen, Stein B.

    2016-01-01

    In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. The variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory, which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying the variational principle to the planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From this principle, a universal mass–radius relation, an estimate of the error propagation from the equation of state to the mass–radius relation, and a form of the virial theorem applicable to planetary interiors are derived.

  6. Finite Element Residual Stress Analysis of Planetary Gear Tooth

    Directory of Open Access Journals (Sweden)

    Jungang Wang

    2013-01-01

    Full Text Available A method to simulate residual stress field of planetary gear is proposed. In this method, the finite element model of planetary gear is established and divided to tooth zone and profile zone, whose different temperature field is set. The gear's residual stress simulation is realized by the thermal compression stress generated by the temperature difference. Based on the simulation, the finite element model of planetary gear train is established, the dynamic meshing process is simulated, and influence of residual stress on equivalent stress of addendum, pitch circle, and dedendum of internal and external meshing planetary gear tooth profile is analyzed, according to non-linear contact theory, thermodynamic theory, and finite element theory. The results show that the equivalent stresses of planetary gear at both meshing and nonmeshing surface are significantly and differently reduced by residual stress. The study benefits fatigue cracking analysis and dynamic optimization design of planetary gear train.

  7. Life Support and Habitation and Planetary Protection Workshop

    Science.gov (United States)

    Hogan, John A. (Editor); Race, Margaret S. (Editor); Fisher, John W. (Editor); Joshi, Jitendra A. (Editor); Rummel, John D. (Editor)

    2006-01-01

    A workshop entitled "Life Support and Habitation and Planetary Protection Workshop" was held in Houston, Texas on April 27-29, 2005 to facilitate the development of planetary protection guidelines for future human Mars exploration missions and to identify the potential effects of these guidelines on the design and selection of related human life support, extravehicular activity and monitoring and control systems. This report provides a summary of the workshop organization, starting assumptions, working group results and recommendations. Specific result topics include the identification of research and technology development gaps, potential forward and back contaminants and pathways, mitigation alternatives, and planetary protection requirements definition needs. Participants concluded that planetary protection and science-based requirements potentially affect system design, technology trade options, development costs and mission architecture. Therefore early and regular coordination between the planetary protection, scientific, planning, engineering, operations and medical communities is needed to develop workable and effective designs for human exploration of Mars.

  8. Young planetary nebula with OH molecules - NGC 6302

    International Nuclear Information System (INIS)

    Payne, H.E.; Phillips, J.A.; Terzian, Y.

    1988-01-01

    The results of a sensitive survey of planetary nebulae in all four ground-state OH lines are reported. The results confirm that evolved planetary nebulas are not OH sources in general. However, one interesting object was not detected: an OH 1612 MHz maser in the young planetary nebula NGC 6302. This nebula may be in a brief evolutionary stage, similar to the young and compact planetary nebula Vy 2-2, where OH has already been detected. In addition, the results of further observations of NGC 6302 are reported, including VLA observations of the 1612 MHz line and continuum emission and detections of rotationally excited OH lines at 5-cm wavelength in absorption. 28 references

  9. An online planetary exploration tool: ;Country Movers;

    Science.gov (United States)

    Gede, Mátyás; Hargitai, Henrik

    2017-08-01

    Results in astrogeologic investigations are rarely communicated towards the general public by maps despite the new advances in planetary spatial informatics and new spatial datasets in high resolution and more complete coverage. Planetary maps are typically produced by astrogeologists for other professionals, and not by cartographers for the general public. We report on an application designed for students, which uses cartography as framework to aid the virtual exploration of other planets and moons, using the concepts of size comparison and travel time calculation. We also describe educational activities that build on geographic knowledge and expand it to planetary surfaces.

  10. Mars Technology Program: Planetary Protection Technology Development

    Science.gov (United States)

    Lin, Ying

    2006-01-01

    This slide presentation reviews the development of Planetary Protection Technology in the Mars Technology Program. The goal of the program is to develop technologies that will enable NASA to build, launch, and operate a mission that has subsystems with different Planetary Protection (PP) classifications, specifically for operating a Category IVb-equivalent subsystem from a Category IVa platform. The IVa category of planetary protection requires bioburden reduction (i.e., no sterilization is required) The IVb category in addition to IVa requirements: (i.e., terminal sterilization of spacecraft is required). The differences between the categories are further reviewed.

  11. Optical observations of southern planetary nebula candidates

    NARCIS (Netherlands)

    VandeSteene, GC; Sahu, KC; Pottasch, [No Value

    1996-01-01

    We present H alpha+[NII] images and low resolution spectra of 16 IRAS-selected, southern planetary nebula candidates previously detected in the radio continuum. The H alpha+[NII] images are presented as finding charts. Contour plots are shown for the resolved planetary nebulae. From these images

  12. A history of presatellite investigations of the earth's radiation budget

    Science.gov (United States)

    Hunt, G. E.; Kandel, R.; Mecherikunnel, A. T.

    1986-01-01

    The history of radiation budget studies from the early twentieth century to the advent of the space age is reviewed. By the beginning of the 1960's, accurate radiative models had been developed capable of estimating the global and zonally averaged components of the radiation budget, though great uncertainty in the derived parameters existed due to inaccuracy of the data describing the physical parameters used in the model, associated with clouds, the solar radiation, and the gaseous atmospheric absorbers. Over the century, the planetary albedo estimates had reduced from 89 to 30 percent.

  13. Simulations of the Urban Planetary Boundary Layer in an Arid Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Grossman-Clarke, Susanne; Liu, Yubao; Zehnder, Joseph A.; Fast, Jerome D.

    2008-03-15

    Characteristics of the summertime urban planetary boundary layer (PBL) were investigated for the arid Phoenix (Arizona, USA) metropolitan region using simulated data as well as observations from two field campaigns conducted in May/June 1998 and June 2001. A version of the fifth-generation PSU/NCAR mesoscale meteorological model (MM5) was applied that included a refined land cover classification and updated land use/cover data for Phoenix as well as bulk approaches of characteristics of the urban surface energy balance. Planetary boundary layer processes were simulated by a modified version of MM5¹s non-local closure Medium Range Forecast (MRF) scheme that was enhanced by new surface flux and non-local mixing approaches to better capture near-surface wind speeds and the evolution of the planetary boundary layer. Simulated potential temperature profiles were tested against radiosonde data, indicating that the PBL scheme was able to simulate the evolution and height of the PBL with good accuracy and better than the original MRF scheme. During both simulation periods, MM5¹s performance for near-surface meteorological variables in the urban area was consistently improved by the modifications applied to the standard MM5. The results showed that the urban PBL evolved faster after sunrise than the rural PBL due to the reminiscence of the nighttime urban heat island and its influence on the flow field and surface sensible heat fluxes. During afternoon hours the urban PBL was lower than the rural PBL due to the higher water availability for evaporation in the urban area and accompanying lower sensible heat fluxes. No consistent differences between the urban and rural PBL were detected during nighttime because of deviations in air flow and accompanying wind shear.

  14. The activities and prospect of planetary protection research in China

    Science.gov (United States)

    Li, Ming

    2016-07-01

    Planetary protection is an important activities and responsibilities for space exploration. In Chinese manned missions, micro-organism research and protection has been developed in Shenzhou-9, Shenzhou-10 and Tiangong-2 missions. In the experiment facility of Lunar Palace-1, the micro-organism pollution and protection/control technology has been studied. In the lunar sample recovery mission and China Mars mission, the planetary protection has become an important issue. This paper introduced the research about planetary protection in China. The planetary protection activities, strategy and procedures have been suggested for future space exploration program to meet the requirement for planetary protection, such as cabin pollution isolation, pollutant detection, and so on.

  15. The brazilian indigenous planetary-observatory

    Science.gov (United States)

    Afonso, G. B.

    2003-08-01

    We have performed observations of the sky alongside with the Indians of all Brazilian regions that made it possible localize many indigenous constellations. Some of these constellations are the same as the other South American Indians and Australian aborigines constellations. The scientific community does not have much of this information, which may be lost in one or two generations. In this work, we present a planetary-observatory that we have made in the Park of Science Newton Freire-Maia of Paraná State, in order to popularize the astronomical knowledge of the Brazilian Indians. The planetary consists, essentially, of a sphere of six meters in diameter and a projection cylinder of indigenous constellations. In this planetary we can identify a lot of constellations that we have gotten from the Brazilian Indians; for instance, the four seasonal constellations: the Tapir (spring), the Old Man (summer), the Deer (autumn) and the Rhea (winter). A two-meter height wooden staff that is posted vertically on the horizontal ground similar to a Gnomon and stones aligned with the cardinal points and the soltices directions constitutes the observatory. A stone circle of ten meters in diameter surrounds the staff and the aligned stones. During the day we observe the Sun apparent motions and at night the indigenous constellations. Due to the great community interest in our work, we are designing an itinerant indigenous planetary-observatory to be used in other cities mainly by indigenous and primary schools teachers.

  16. Hydrodynamic escape from planetary atmospheres

    Science.gov (United States)

    Tian, Feng

    Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Due to the existence of a singularity point near the transonic point, it is difficult to find transonic steady state solutions by solving the time-independent hydrodynamic equations. In addition to that, most previous works assume that all energy driving the escape flow is deposited in one narrow layer. This assumption not only results in less accurate solutions to the hydrodynamic escape problem, but also makes it difficult to include other chemical and physical processes in the hydrodynamic escape models. In this work, a numerical model describing the transonic hydrodynamic escape from planetary atmospheres is developed. A robust solution technique is used to solve the time dependent hydrodynamic equations. The method has been validated in an isothermal atmosphere where an analytical solution is available. The hydrodynamic model is applied to 3 cases: hydrogen escape from small orbit extrasolar planets, hydrogen escape from a hydrogen rich early Earth's atmosphere, and nitrogen/methane escape from Pluto's atmosphere. Results of simulations on extrasolar planets are in good agreement with the observations of the transiting extrasolar planet HD209458b. Hydrodynamic escape of hydrogen from other hypothetical close-in extrasolar planets are simulated and the influence of hydrogen escape on the long-term evolution of these extrasolar planets are discussed. Simulations on early Earth suggest that hydrodynamic escape of hydrogen from a hydrogen rich early Earth's atmosphere is about two orders magnitude slower than the diffusion limited escape rate. A hydrogen rich early Earth's atmosphere could have been maintained by the balance between the hydrogen escape and the supply of hydrogen into the atmosphere by volcanic outgassing. Origin of life may have occurred in the organic soup ocean created by the efficient formation of prebiotic molecules in the hydrogen rich early

  17. Effects of anthropogenic aerosol particles on the radiation balance of the atmosphere. Einfluss anthropogener Aerosolteilchen auf den Strahlungshaushalt der Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Newiger, M

    1985-01-01

    The influence of aerosol particles is assessed on the basis of the changes in the climate parameters ''albedo'' and ''neutron flux''. Apart from the directly emitted particles, particles formed in the atmosphere as a result of SO/sub 2/ emissions are investigated. The model of aerosol effects on the radiation field takes account of the feedback with the microphysical parameters of the clouds. In the investigation, given particle concentrations were recalculated for three size classes using a two-dimensional transport model. The particle size distribution is described by a modified power function. Extreme-value estimates are made because the absorption capacity of anthropogenic particles is little known. A comparison of the climatic effects of anthropogenic activities shows that aerosol particles and SO/sub 2/ emissions have opposite effects on the radiation balance. (orig./PW).

  18. An energy balance model for the Greenland ice sheet

    NARCIS (Netherlands)

    Wal, R.S.W. van de; Oerlemans, J.

    1994-01-01

    The sensitivity of the mass balance of the Greenland Ice Sheet is studied by means of an energy balance model. The model calculates the shortwave and longwave radiation and the turbulent fluxes on a grid with a grid point spacing of 20 km. Special attention is given to the parameterization of the

  19. A Common Probe Design for Multiple Planetary Destinations

    Science.gov (United States)

    Hwang, H. H.; Allen, G. A., Jr.; Alunni, A. I.; Amato, M. J.; Atkinson, D. H.; Bienstock, B. J.; Cruz, J. R.; Dillman, R. A.; Cianciolo, A. D.; Elliott, J. O.; hide

    2018-01-01

    Atmospheric probes have been successfully flown to planets and moons in the solar system to conduct in situ measurements. They include the Pioneer Venus multi-probes, the Galileo Jupiter probe, and Huygens probe. Probe mission concepts to five destinations, including Venus, Jupiter, Saturn, Uranus, and Neptune, have all utilized similar-shaped aeroshells and concept of operations, namely a 45-degree sphere cone shape with high density heatshield material and parachute system for extracting the descent vehicle from the aeroshell. Each concept designed its probe to meet specific mission requirements and to optimize mass, volume, and cost. At the 2017 International Planetary Probe Workshop (IPPW), NASA Headquarters postulated that a common aeroshell design could be used successfully for multiple destinations and missions. This "common probe"� design could even be assembled with multiple copies, properly stored, and made available for future NASA missions, potentially realizing savings in cost and schedule and reducing the risk of losing technologies and skills difficult to sustain over decades. Thus the NASA Planetary Science Division funded a study to investigate whether a common probe design could meet most, if not all, mission needs to the five planetary destinations with extreme entry environments. The Common Probe study involved four NASA Centers and addressed these issues, including constraints and inefficiencies that occur in specifying a common design. Study methodology: First, a notional payload of instruments for each destination was defined based on priority measurements from the Planetary Science Decadal Survey. Steep and shallow entry flight path angles (EFPA) were defined for each planet based on qualification and operational g-load limits for current, state-of-the-art instruments. Interplanetary trajectories were then identified for a bounding range of EFPA. Next, 3-degrees-of-freedom simulations for entry trajectories were run using the entry state

  20. Formation of planetary systems

    International Nuclear Information System (INIS)

    Brahic, A.

    1982-01-01

    It seemed appropriate to devote the 1980 School to the origin of the solar system and more particularly to the formation of planetary systems (dynamic accretion processes, small bodies, planetary rings, etc...) and to the physics and chemistry of planetary interiors, surface and atmospheres (physical and chemical constraints associated with their formation). This Summer School enabled both young researchers and hard-nosed scientists, gathered together in idyllic surroundings, to hold numerous discussions, to lay the foundations for future cooperation, to acquire an excellent basic understanding, and to make many useful contacts. This volume reflects the lectures and presentations that were delivered in this Summer School setting. It is aimed at both advanced students and research workers wishing to specialize in planetology. Every effort has been made to give an overview of the basic knowledge required in order to gain a better understanding of the origin of the solar system. Each article has been revised by one or two referees whom I would like to thank for their assistance. Between the end of the School in August 1980 and the publication of this volume in 1982, the Voyager probes have returned a wealth of useful information. Some preliminary results have been included for completeness

  1. Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    André, Nicolas; Grande, Manuel

    2016-04-01

    Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI) will include an entirely new Virtual Access Service, WP5 VA1 "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. VA1 will make five entirely new 'toolkits' accessible to the research community and to industrial partners planning for space missions: a general planetary space weather toolkit, as well as three toolkits dedicated to the following key planetary environments: Mars (in support ExoMars), comets (building on the expected success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUICE mission to be launched in 2022). This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather in the tools and models available within the partner institutes. It will also create a novel event-diary toolkit aiming at predicting and detecting planetary events like meteor showers and impacts. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. So WP10 JRA4 "Planetary Space Weather Services" (PSWS) will provide the additional research and tailoring required to apply them for these purposes. The overall objectives of this Joint Research Aactivities will be to review, test, improve and adapt methods and tools available within the partner institutes in order to make prototype planetary event and space weather services operational in

  2. To See the Unseen: A History of Planetary Radar Astronomy

    Science.gov (United States)

    Butrica, Andrew J.

    1996-01-01

    This book relates the history of planetary radar astronomy from its origins in radar to the present day and secondarily to bring to light that history as a case of 'Big Equipment but not Big Science'. Chapter One sketches the emergence of radar astronomy as an ongoing scientific activity at Jodrell Bank, where radar research revealed that meteors were part of the solar system. The chief Big Science driving early radar astronomy experiments was ionospheric research. Chapter Two links the Cold War and the Space Race to the first radar experiments attempted on planetary targets, while recounting the initial achievements of planetary radar, namely, the refinement of the astronomical unit and the rotational rate and direction of Venus. Chapter Three discusses early attempts to organize radar astronomy and the efforts at MIT's Lincoln Laboratory, in conjunction with Harvard radio astronomers, to acquire antenna time unfettered by military priorities. Here, the chief Big Science influencing the development of planetary radar astronomy was radio astronomy. Chapter Four spotlights the evolution of planetary radar astronomy at the Jet Propulsion Laboratory, a NASA facility, at Cornell University's Arecibo Observatory, and at Jodrell Bank. A congeries of funding from the military, the National Science Foundation, and finally NASA marked that evolution, which culminated in planetary radar astronomy finding a single Big Science patron, NASA. Chapter Five analyzes planetary radar astronomy as a science using the theoretical framework provided by philosopher of science Thomas Kuhn. Chapter Six explores the shift in planetary radar astronomy beginning in the 1970s that resulted from its financial and institutional relationship with NASA Big Science. Chapter Seven addresses the Magellan mission and its relation to the evolution of planetary radar astronomy from a ground-based to a space-based activity. Chapters Eight and Nine discuss the research carried out at ground

  3. Collisional stripping of planetary crusts

    Science.gov (United States)

    Carter, Philip J.; Leinhardt, Zoë M.; Elliott, Tim; Stewart, Sarah T.; Walter, Michael J.

    2018-02-01

    Geochemical studies of planetary accretion and evolution have invoked various degrees of collisional erosion to explain differences in bulk composition between planets and chondrites. Here we undertake a full, dynamical evaluation of 'crustal stripping' during accretion and its key geochemical consequences. Crusts are expected to contain a significant fraction of planetary budgets of incompatible elements, which include the major heat producing nuclides. We present smoothed particle hydrodynamics simulations of collisions between differentiated rocky planetesimals and planetary embryos. We find that the crust is preferentially lost relative to the mantle during impacts, and we have developed a scaling law based on these simulations that approximates the mass of crust that remains in the largest remnant. Using this scaling law and a recent set of N-body simulations of terrestrial planet formation, we have estimated the maximum effect of crustal stripping on incompatible element abundances during the accretion of planetary embryos. We find that on average approximately one third of the initial crust is stripped from embryos as they accrete, which leads to a reduction of ∼20% in the budgets of the heat producing elements if the stripped crust does not reaccrete. Erosion of crusts can lead to non-chondritic ratios of incompatible elements, but the magnitude of this effect depends sensitively on the details of the crust-forming melting process on the planetesimals. The Lu/Hf system is fractionated for a wide range of crustal formation scenarios. Using eucrites (the products of planetesimal silicate melting, thought to represent the crust of Vesta) as a guide to the Lu/Hf of planetesimal crust partially lost during accretion, we predict the Earth could evolve to a superchondritic 176Hf/177Hf (3-5 parts per ten thousand) at present day. Such values are in keeping with compositional estimates of the bulk Earth. Stripping of planetary crusts during accretion can lead to

  4. DEFINITION OF THE GEAR’S GEOMETRY IN THE PLANETARY CYCLOIDAL TRANSMISSION

    Directory of Open Access Journals (Sweden)

    Sławomir BEDNARCZYK

    2014-03-01

    Full Text Available In the paper, the design and operation of the planetary cycloidal transmission have been discussed. The transmission is a synthesis of the planetary and the straight-line mechanism. The planetary mechanism is made of a planetary gear set with rollers, which is critical for the proper work of the transmission. Its basic and most important element is the planetary cycloidal gear. Influence of the parameters determining the cycloidal profile of the gear on the gear’s geometry and the forces has been presented. The straight-line mechanism carrying the motion from the driving onto the driven unit of the transmission is made of the pins and bushes located in the holes of the planetary gears. The influence of the number and geometry of the elements on the forces and occuring in the holes of the planetary gears has been presented. Therefore, the properly defined geometry of the gear and of the material of which the gear is made is crucial for the safe operation of the planetary cycloidal transmission.

  5. The effects of mass and metallicity upon planetary nebula formation

    Science.gov (United States)

    Papp, K. A.; Purton, C. R.; Kwok, S.

    1983-05-01

    A parameterized function is constructed which describes the possible dependence of planetary nebula formation upon metal abundance and stellar mass. Data on galaxies in the Local Group compared with predictions made from the parameterized function indicate that heavy element abundance is the principal agent influencing the formation of planetary nebulae; stars which are rich in heavy elements are the progenitors of planetary nebulae. This analysis, when compared with the observations, argues for a modest degree of pre-enrichment in a few of the sample galaxies. The heavy element dependence of planetary nebula formation also accounts for the deficit of planetary nebulae in the nuclei of NGC 221 and NGC 224, and in the bulge of our Galaxy.

  6. Lay and Expert Perceptions of Planetary Protection

    Science.gov (United States)

    Race, Margaret S.; MacGregor, Donald G.; Slovic, Paul

    2000-01-01

    As space scientists and engineers plan new missions to Mars and other planets in our solar system, they will face critical questions about the potential for biological contamination of planetary surfaces. In a society that places ever-increasing importance on the role of public involvement in science and technology policy, questions about risks of biological contamination will be examined and debated in the media, and will lead to the formation of public perceptions of planetary-contamination risks. These perceptions will, over time, form an important input to the development of space policy. Previous research in public and expert perceptions of technological risks and hazards has shown that many of the problems faced by risk-management organizations are the result of differing perceptions of risk (and risk management) between the general public and scientific and technical experts. These differences manifest themselves both as disagreements about the definition (and level) of risk associated with a scientific, technological or industrial enterprise, and as distrust about the ability of risk-management organizations (both public and private) to adequately protect people's health and safety. This report presents the results of a set of survey studies designed to reveal perceptions of planetary exploration and protection from a wide range of respondents, including both members of the general public and experts in the life sciences. The potential value of this research lies in what it reveals about perceptions of risk and benefit that could improve risk-management policies and practices. For example, efforts to communicate with the public about Mars sample return missions could benefit from an understanding of the specific concerns that nonscientists have about such a mission by suggesting areas of potential improvement in public education and information. Assessment of both public and expert perceptions of risk can also be used to provide an advanced signal of

  7. Standards-Based Open-Source Planetary Map Server: Lunaserv

    Science.gov (United States)

    Estes, N. M.; Silva, V. H.; Bowley, K. S.; Lanjewar, K. K.; Robinson, M. S.

    2018-04-01

    Lunaserv is a planetary capable Web Map Service developed by the LROC SOC. It enables researchers to serve their own planetary data to a wide variety of GIS clients without any additional processing or download steps.

  8. Study on Cracking Mechanism of Hardened Planetary frame

    Science.gov (United States)

    Li, Xinghui

    2017-09-01

    Planetary carrier made by 45 steel appear quenching crack, which is analyzed in chemical composition, hardness test and metallographic microscopic structure. The reasons of quenching crack of planetary gear include the unreasonable structure of the planetary carrier, thinner annular wall on the base of the upper part, and in dangerous area of the 45 steel in the process of quenching. The faster cooling rate of quenching results in a centripetal stress with the thick-wall part, which is greater than the ultimate bearing capacity of the material.

  9. Energy balance in the ohmically heated FT

    International Nuclear Information System (INIS)

    Bartiromo, R.; Brusati, M.; Cilloco, F.

    1981-01-01

    A typical discharge in the FT Tokamak at 60 kG has been studied in detail in order to derive the power balance between the ohmic input and the plasma losses. Impurity and radiation losses together with ion and electron energy balance are discussed. A power transport term for electrons is derived which is ascribed to anomalous thermal conduction. This resulting thermal transport is compared with those derived from different proposed scalings

  10. Charging of Individual Micron-Size Interstellar/Planetary Dust Grains by Secondary Electron Emissions

    Science.gov (United States)

    Tankosic, D.; Abbas, M. M.

    2012-01-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper, we discuss experimental results on dust charging by electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Currently, very limited experimental data are available for charging of individual micron-size dust grains, particularly by low energy electron impact. Available theoretical models based on the Sternglass equation (Sternglass, 1954) are applicable for neutral, planar, and bulk surfaces only. However, charging properties of individual micron-size dust grains are expected to be different from the values measured on bulk materials. Our recent experimental results on individual, positively charged, micron-size lunar dust grains levitated in an electrodynamic balance facility (at NASA-MSFC) indicate that the SEE by electron impact is a complex process. The electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (e.g. Abbas et al, 2010). Here we discuss the complex nature of SEE charging properties of individual micron-size lunar dust grains and silica microspheres.

  11. Long-term Satellite Observations of Cloud and Aerosol Radiative Effects Using the (A)ATSR Satellite Data Record

    Science.gov (United States)

    Christensen, M.; McGarragh, G.; Thomas, G.; Povey, A.; Proud, S.; Poulsen, C. A.; Grainger, R. G.

    2016-12-01

    Radiative forcing by clouds, aerosols, and their interactions constitute some of the largest sources of uncertainties in the climate system (Chapter 7 IPCC, 2013). It is essential to understand the past through examination of long-term satellite observation records to provide insight into the uncertainty characteristics of these radiative forcers. As part of the ESA CCI (Climate Change Initiative) we have recently implemented a broadband radiative flux algorithm (known as BUGSrad) into the Optimal Retrieval for Aerosol and Cloud (ORAC) scheme. ORAC achieves radiative consistency of its aerosol and cloud products through an optimal estimation scheme and is highly versatile, enabling retrievals for numerous satellite sensors: ATSR, MODIS, VIIRS, AVHRR, SLSTR, SEVIRI, and AHI. An analysis of the 17-year well-calibrated Along Track Scanning Radiometer (ATSR) data is used to quantify trends in cloud and aerosol radiative effects over a wide range of spatiotemporal scales. The El Niño Southern Oscillation stands out as the largest contributing mode of variability to the radiative energy balance (long wave and shortwave fluxes) at the top of the atmosphere. Furthermore, trends in planetary albedo show substantial decreases across the Arctic Ocean (likely due to the melting of sea ice and snow) and modest increases in regions dominated by stratocumulus (e.g., off the coast of California) through notable increases in cloud fraction and liquid water path. Finally, changes in volcanic activity and biomass burning aerosol over this period show sizeable radiative forcing impacts at local-scales. We will demonstrate that radiative forcing from aerosols and clouds have played a significant role in the identified key climate processes using 17 years of satellite observational data.

  12. Planetary Cartography - Activities and Current Challenges

    Science.gov (United States)

    Nass, Andrea; Di, Kaichang; Elgner, Stephan; van Gasselt, Stephan; Hare, Trent; Hargitai, Henrik; Karachevtseva, Irina; Kereszturi, Akos; Kersten, Elke; Kokhanov, Alexander; Manaud, Nicolas; Roatsch, Thomas; Rossi, Angelo Pio; Skinner, James, Jr.; Wählisch, Marita

    2018-05-01

    Maps are one of the most important tools for communicating geospatial information between producers and receivers. Geospatial data, tools, contributions in geospatial sciences, and the communication of information and transmission of knowledge are matter of ongoing cartographic research. This applies to all topics and objects located on Earth or on any other body in our Solar System. In planetary science, cartography and mapping have a history dating back to the roots of telescopic space exploration and are now facing new technological and organizational challenges with the rise of new missions, new global initiatives, organizations and opening research markets. The focus of this contribution is to introduce the community to the field of planetary cartography and its historic foundation, to highlight some of the organizations involved and to emphasize challenges that Planetary Cartography has to face today and in the near future.

  13. Planetary Data Systems (PDS) Imaging Node Atlas II

    Science.gov (United States)

    Stanboli, Alice; McAuley, James M.

    2013-01-01

    The Planetary Image Atlas (PIA) is a Rich Internet Application (RIA) that serves planetary imaging data to the science community and the general public. PIA also utilizes the USGS Unified Planetary Coordinate system (UPC) and the on-Mars map server. The Atlas was designed to provide the ability to search and filter through greater than 8 million planetary image files. This software is a three-tier Web application that contains a search engine backend (MySQL, JAVA), Web service interface (SOAP) between server and client, and a GWT Google Maps API client front end. This application allows for the search, retrieval, and download of planetary images and associated meta-data from the following missions: 2001 Mars Odyssey, Cassini, Galileo, LCROSS, Lunar Reconnaissance Orbiter, Mars Exploration Rover, Mars Express, Magellan, Mars Global Surveyor, Mars Pathfinder, Mars Reconnaissance Orbiter, MESSENGER, Phoe nix, Viking Lander, Viking Orbiter, and Voyager. The Atlas utilizes the UPC to translate mission-specific coordinate systems into a unified coordinate system, allowing the end user to query across missions of similar targets. If desired, the end user can also use a mission-specific view of the Atlas. The mission-specific views rely on the same code base. This application is a major improvement over the initial version of the Planetary Image Atlas. It is a multi-mission search engine. This tool includes both basic and advanced search capabilities, providing a product search tool to interrogate the collection of planetary images. This tool lets the end user query information about each image, and ignores the data that the user has no interest in. Users can reduce the number of images to look at by defining an area of interest with latitude and longitude ranges.

  14. Interoperability in planetary research for geospatial data analysis

    Science.gov (United States)

    Hare, Trent M.; Rossi, Angelo P.; Frigeri, Alessandro; Marmo, Chiara

    2018-01-01

    For more than a decade there has been a push in the planetary science community to support interoperable methods for accessing and working with geospatial data. Common geospatial data products for planetary research include image mosaics, digital elevation or terrain models, geologic maps, geographic location databases (e.g., craters, volcanoes) or any data that can be tied to the surface of a planetary body (including moons, comets or asteroids). Several U.S. and international cartographic research institutions have converged on mapping standards that embrace standardized geospatial image formats, geologic mapping conventions, U.S. Federal Geographic Data Committee (FGDC) cartographic and metadata standards, and notably on-line mapping services as defined by the Open Geospatial Consortium (OGC). The latter includes defined standards such as the OGC Web Mapping Services (simple image maps), Web Map Tile Services (cached image tiles), Web Feature Services (feature streaming), Web Coverage Services (rich scientific data streaming), and Catalog Services for the Web (data searching and discoverability). While these standards were developed for application to Earth-based data, they can be just as valuable for planetary domain. Another initiative, called VESPA (Virtual European Solar and Planetary Access), will marry several of the above geoscience standards and astronomy-based standards as defined by International Virtual Observatory Alliance (IVOA). This work outlines the current state of interoperability initiatives in use or in the process of being researched within the planetary geospatial community.

  15. Visualization of Kepler's Laws of Planetary Motion

    Science.gov (United States)

    Lu, Meishu; Su, Jun; Wang, Weiguo; Lu, Jianlong

    2017-01-01

    For this article, we use a 3D printer to print a surface similar to universal gravitation for demonstrating and investigating Kepler's laws of planetary motion describing the motion of a small ball on the surface. This novel experimental method allows Kepler's laws of planetary motion to be visualized and will contribute to improving the…

  16. Handbook of cosmic hazards and planetary defense

    CERN Document Server

    Allahdadi, Firooz

    2015-01-01

    Covers in a comprehensive fashion all aspects of cosmic hazards and possible strategies for contending with these threats through a comprehensive planetary defense strategy. This handbook brings together in a single reference work a rich blend of information about the various types of cosmic threats that are posed to human civilization by asteroids, comets, bolides, meteors, solar flares and coronal mass ejections, cosmic radiation and other types of threats that are only recently beginning to be understood and studied, such as investigation of the “cracks” in the protective shield provided by the Van Allen belts and the geomagnetosphere, of matter-antimatter collisions, orbital debris and radiological or biological contamination. Some areas that are addressed involve areas about which there is a good deal of information that has been collected for many decades by multiple space missions run by many different space agencies, observatories and scientific researchers. Other areas involving research and ...

  17. Abundance determinations in HII regions and planetary nebulae

    OpenAIRE

    Stasinska, Grazyna

    2002-01-01

    The methods of abundance determinations in HII regions and planetary nebulae are described, with emphasis on the underlying assumptions and inherent problems. Recent results on abundances in Galactic HII regions and in Galactic and extragalactic Planetary Nebulae are reviewed.

  18. The signatures of the parental cluster on field planetary systems

    Science.gov (United States)

    Cai, Maxwell Xu; Portegies Zwart, Simon; van Elteren, Arjen

    2018-03-01

    Due to the high stellar densities in young clusters, planetary systems formed in these environments are likely to have experienced perturbations from encounters with other stars. We carry out direct N-body simulations of multiplanet systems in star clusters to study the combined effects of stellar encounters and internal planetary dynamics. These planetary systems eventually become part of the Galactic field population as the parental cluster dissolves, which is where most presently known exoplanets are observed. We show that perturbations induced by stellar encounters lead to distinct signatures in the field planetary systems, most prominently, the excited orbital inclinations and eccentricities. Planetary systems that form within the cluster's half-mass radius are more prone to such perturbations. The orbital elements are most strongly excited in the outermost orbit, but the effect propagates to the entire planetary system through secular evolution. Planet ejections may occur long after a stellar encounter. The surviving planets in these reduced systems tend to have, on average, higher inclinations and larger eccentricities compared to systems that were perturbed less strongly. As soon as the parental star cluster dissolves, external perturbations stop affecting the escaped planetary systems, and further evolution proceeds on a relaxation time-scale. The outer regions of these ejected planetary systems tend to relax so slowly that their state carries the memory of their last strong encounter in the star cluster. Regardless of the stellar density, we observe a robust anticorrelation between multiplicity and mean inclination/eccentricity. We speculate that the `Kepler dichotomy' observed in field planetary systems is a natural consequence of their early evolution in the parental cluster.

  19. Planetary Society

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Carl Sagan, Bruce Murray and Louis Friedman founded the non-profit Planetary Society in 1979 to advance the exploration of the solar system and to continue the search for extraterrestrial life. The Society has its headquarters in Pasadena, California, but is international in scope, with 100 000 members worldwide, making it the largest space interest group in the world. The Society funds a var...

  20. The Possible Role of Penning Ionization Processes in Planetary Atmospheres

    Directory of Open Access Journals (Sweden)

    Stefano Falcinelli

    2015-03-01

    Full Text Available In this paper we suggest Penning ionization as an important route of formation for ionic species in upper planetary atmospheres. Our goal is to provide relevant tools to researchers working on kinetic models of atmospheric interest, in order to include Penning ionizations in their calculations as fast processes promoting reactions that cannot be neglected. Ions are extremely important for the transmission of radio and satellite signals, and they govern the chemistry of planetary ionospheres. Molecular ions have also been detected in comet tails. In this paper recent experimental results concerning production of simple ionic species of atmospheric interest are presented and discussed. Such results concern the formation of free ions in collisional ionization of H2O, H2S, and NH3 induced by highly excited species (Penning ionization as metastable noble gas atoms. The effect of Penning ionization still has not been considered in the modeling of terrestrial and extraterrestrial objects so far, even, though metastable helium is formed by radiative recombination of He+ ions with electrons. Because helium is the second most abundant element of the universe, Penning ionization of atomic or molecular species by He*(23S1 is plausibly an active route of ionization in relatively dense environments exposed to cosmic rays.

  1. The New Planetary Science Archive (PSA): Exploration and Discovery of Scientific Datasets from ESA's Planetary Missions

    Science.gov (United States)

    Heather, David; Besse, Sebastien; Vallat, Claire; Barbarisi, Isa; Arviset, Christophe; De Marchi, Guido; Barthelemy, Maud; Coia, Daniela; Costa, Marc; Docasal, Ruben; Fraga, Diego; Grotheer, Emmanuel; Lim, Tanya; MacFarlane, Alan; Martinez, Santa; Rios, Carlos; Vallejo, Fran; Saiz, Jaime

    2017-04-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific datasets through various interfaces at http://psa.esa.int. All datasets are scientifically peer-reviewed by independent scientists, and are compliant with the Planetary Data System (PDS) standards. The PSA is currently implementing a number of significant improvements, mostly driven by the evolution of the PDS standard, and the growing need for better interfaces and advanced applications to support science exploitation. As of the end of 2016, the PSA is hosting data from all of ESA's planetary missions. This includes ESA's first planetary mission Giotto that encountered comet 1P/Halley in 1986 with a flyby at 800km. Science data from Venus Express, Mars Express, Huygens and the SMART-1 mission are also all available at the PSA. The PSA also contains all science data from Rosetta, which explored comet 67P/Churyumov-Gerasimenko and asteroids Steins and Lutetia. The year 2016 has seen the arrival of the ExoMars 2016 data in the archive. In the upcoming years, at least three new projects are foreseen to be fully archived at the PSA. The BepiColombo mission is scheduled for launch in 2018. Following that, the ExoMars Rover Surface Platform (RSP) in 2020, and then the JUpiter ICy moon Explorer (JUICE). All of these will archive their data in the PSA. In addition, a few ground-based support programmes are also available, especially for the Venus Express and Rosetta missions. The newly designed PSA will enhance the user experience and will significantly reduce the complexity for users to find their data promoting one-click access to the scientific datasets with more customized views when needed. This includes a better integration with Planetary GIS analysis tools and Planetary interoperability services (search and retrieve data, supporting e.g. PDAP, EPN-TAP). It will also be up

  2. NASA Johnson Space Center's Planetary Sample Analysis and Mission Science (PSAMS) Laboratory: A National Facility for Planetary Research

    Science.gov (United States)

    Draper, D. S.

    2016-01-01

    NASA Johnson Space Center's (JSC's) Astromaterials Research and Exploration Science (ARES) Division, part of the Exploration Integration and Science Directorate, houses a unique combination of laboratories and other assets for conducting cutting edge planetary research. These facilities have been accessed for decades by outside scientists, most at no cost and on an informal basis. ARES has thus provided substantial leverage to many past and ongoing science projects at the national and international level. Here we propose to formalize that support via an ARES/JSC Plane-tary Sample Analysis and Mission Science Laboratory (PSAMS Lab). We maintain three major research capa-bilities: astromaterial sample analysis, planetary process simulation, and robotic-mission analog research. ARES scientists also support planning for eventual human ex-ploration missions, including astronaut geological training. We outline our facility's capabilities and its potential service to the community at large which, taken together with longstanding ARES experience and expertise in curation and in applied mission science, enable multi-disciplinary planetary research possible at no other institution. Comprehensive campaigns incorporating sample data, experimental constraints, and mission science data can be conducted under one roof.

  3. Dust radiative forcing in snow of the Upper Colorado River Basin: 1. A 6 year record of energy balance, radiation, and dust concentrations

    Science.gov (United States)

    Painter, Thomas H.; Skiles, S. Mckenzie; Deems, Jeffrey S.; Bryant, Ann C.; Landry, Christopher C.

    2012-07-01

    Dust in snow accelerates snowmelt through its direct reduction of snow albedo and its further indirect reduction of albedo by accelerating the growth of snow grains. Since the westward expansion of the United States that began in the mid-19th century, the mountain snow cover of the Colorado River Basin has been subject to five-fold greater dust loading, largely from the Colorado Plateau and Great Basin. Radiative forcing of snowmelt by dust is not captured by conventional micrometeorological measurements, and must be monitored by a more comprehensive suite of radiation instruments. Here we present a 6 year record of energy balance and detailed radiation measurements in the Senator Beck Basin Study Area, San Juan Mountains, Colorado, USA. Data include broadband irradiance, filtered irradiance, broadband reflected flux, filtered reflected flux, broadband and visible albedo, longwave irradiance, wind speed, relative humidity, and air temperatures. The gradient of the snow surface is monitored weekly and used to correct albedo measurements for geometric effects. The snow is sampled weekly for dust concentrations in plots immediately adjacent to each tower over the melt season. Broadband albedo in the last weeks of snow cover ranged from 0.33 to 0.55 across the 6 years and two sites. Total end of year dust concentration in the top 3 cm of the snow column ranged from 0.23 mg g-1 to 4.16 mg g-1. These measurements enable monitoring and modeling of dust and climate-driven snowmelt forcings in the Upper Colorado River Basin.

  4. Interoperability in the Planetary Science Archive (PSA)

    Science.gov (United States)

    Rios Diaz, C.

    2017-09-01

    The protocols and standards currently being supported by the recently released new version of the Planetary Science Archive at this time are the Planetary Data Access Protocol (PDAP), the EuroPlanet- Table Access Protocol (EPN-TAP) and Open Geospatial Consortium (OGC) standards. We explore these protocols in more detail providing scientifically useful examples of their usage within the PSA.

  5. The diversity of planetary system architectures: contrasting theory with observations

    Science.gov (United States)

    Miguel, Y.; Guilera, O. M.; Brunini, A.

    2011-10-01

    In order to explain the observed diversity of planetary system architectures and relate this primordial diversity to the initial properties of the discs where they were born, we develop a semi-analytical model for computing planetary system formation. The model is based on the core instability model for the gas accretion of the embryos and the oligarchic growth regime for the accretion of the solid cores. Two regimes of planetary migration are also included. With this model, we consider different initial conditions based on recent results of protoplanetary disc observations to generate a variety of planetary systems. These systems are analysed statistically, exploring the importance of several factors that define the planetary system birth environment. We explore the relevance of the mass and size of the disc, metallicity, mass of the central star and time-scale of gaseous disc dissipation in defining the architecture of the planetary system. We also test different values of some key parameters of our model to find out which factors best reproduce the diverse sample of observed planetary systems. We assume different migration rates and initial disc profiles, in the context of a surface density profile motivated by similarity solutions. According to this, and based on recent protoplanetary disc observational data, we predict which systems are the most common in the solar neighbourhood. We intend to unveil whether our Solar system is a rarity or whether more planetary systems like our own are expected to be found in the near future. We also analyse which is the more favourable environment for the formation of habitable planets. Our results show that planetary systems with only terrestrial planets are the most common, being the only planetary systems formed when considering low-metallicity discs, which also represent the best environment for the development of rocky, potentially habitable planets. We also found that planetary systems like our own are not rare in the

  6. The final fate of planetary systems

    Science.gov (United States)

    Gaensicke, Boris

    2015-12-01

    The discovery of the first extra-solar planet around a main-sequence star in 1995 has changed the way we think about the Universe: our solar system is not unique. Twenty years later, we know that planetary systems are ubiquitous, orbit stars spanning a wide range in mass, and form in an astonishing variety of architectures. Yet, one fascinating aspect of planetary systems has received relatively little attention so far: their ultimate fate.Most planet hosts will eventually evolve into white dwarfs, Earth-sized stellar embers, and the outer parts of their planetary systems (in the solar system, Mars and beyond) can survive largely intact for billions of years. While scattered and tidally disrupted planetesimals are directly detected at a small number of white dwarfs in the form infrared excess, the most powerful probe for detecting evolved planetary systems is metal pollution of the otherwise pristine H/He atmospheres.I will present the results of a multi-cycle HST survey that has obtained COS observations of 136 white dwarfs. These ultraviolet spectra are exquisitely sensitive to the presence of metals contaminating the white atmosphere. Our sophisticated model atmosphere analysis demonstrates that at least 27% of all targets are currently accreting planetary debris, and an additional 29% have very likely done so in the past. These numbers suggest that planet formation around A-stars (the dominant progenitors of today's white dwarf population) is similarly efficient as around FGK stars.In addition to post-main sequence planetary system demographics, spectroscopy of the debris-polluted white dwarf atmospheres provides a direct window into the bulk composition of exo-planetesimals, analogous to the way we use of meteorites to determine solar-system abundances. Our ultraviolet spectroscopy is particularly sensitive to the detection of Si, a dominant rock-forming species, and we identify up to ten additional volatile and refractory elements in the most strongly

  7. A new planetary nebula in the outer reaches of the Galaxy

    DEFF Research Database (Denmark)

    Viironen, K.; Mampaso, A.; L. M. Corradi, R.

    2011-01-01

    of a new planetary nebula towards the Anticentre direction, IPHASX J052531.19+281945.1 (PNG 178.1-04.0), is presented. The planetary nebula was discovered from the IPHAS survey. Long-slit follow-up spectroscopy was carried out to confirm its planetary nebula nature and to calculate its physical...... and chemical characteristics. The newly discovered planetary nebula turned out to be located at a very large galactocentric distance (D_GC=20.8+-3.8 kpc), larger than any previously known planetary nebula with measured abundances. Its relatively high oxygen abundance (12+log(O/H) = 8.36+-0.03) supports...

  8. Influence of stellar duplicity on the form of planetary nebulae

    International Nuclear Information System (INIS)

    Kolesnik, I.G.; Pilyugin, L.S.

    1986-01-01

    Formation of planetary nebulae's spatial structures is considered. Simple expression for angular distribution of density in planetary nebulae is obtained. Bipolar structures are formed effectively in binary systems in which the velocity of the expanding shell around the main star is smaller than the orbital velocity of the satellite. Masses of satellites lie in the range 0.1-0.4Msub(sun). Theoretical isophotal contour map for the model of the planetary nebula NGC 3587 is consistent with observational data. It is shown that central stars of planetary nebulae are usually binary systems

  9. Post-main-sequence planetary system evolution

    Science.gov (United States)

    Veras, Dimitri

    2016-01-01

    The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level of theoretical scrutiny. Here, I review the diverse dynamical processes which affect planets, asteroids, comets and pebbles as their parent stars evolve into giant branch, white dwarf and neutron stars. This reference provides a foundation for the interpretation and modelling of currently known systems and upcoming discoveries. PMID:26998326

  10. Gazetteer of Planetary Nomenclature

    Data.gov (United States)

    National Aeronautics and Space Administration — Planetary nomenclature, like terrestrial nomenclature, is used to uniquely identify a feature on the surface of a planet or satellite so that the feature can be...

  11. Vibration Based Diagnosis for Planetary Gearboxes Using an Analytical Model

    Directory of Open Access Journals (Sweden)

    Liu Hong

    2016-01-01

    Full Text Available The application of conventional vibration based diagnostic techniques to planetary gearboxes is a challenge because of the complexity of frequency components in the measured spectrum, which is the result of relative motions between the rotary planets and the fixed accelerometer. In practice, since the fault signatures are usually contaminated by noises and vibrations from other mechanical components of gearboxes, the diagnostic efficacy may further deteriorate. Thus, it is essential to develop a novel vibration based scheme to diagnose gear failures for planetary gearboxes. Following a brief literature review, the paper begins with the introduction of an analytical model of planetary gear-sets developed by the authors in previous works, which can predict the distinct behaviors of fault introduced sidebands. This analytical model is easy to implement because the only prerequisite information is the basic geometry of the planetary gear-set. Afterwards, an automated diagnostic scheme is proposed to cope with the challenges associated with the characteristic configuration of planetary gearboxes. The proposed vibration based scheme integrates the analytical model, a denoising algorithm, and frequency domain indicators into one synergistic system for the detection and identification of damaged gear teeth in planetary gearboxes. Its performance is validated with the dynamic simulations and the experimental data from a planetary gearbox test rig.

  12. Long-term global distribution of earth's shortwave radiation budget at the top of atmosphere

    Directory of Open Access Journals (Sweden)

    N. Hatzianastassiou

    2004-01-01

    Full Text Available The mean monthly shortwave (SW radiation budget at the top of atmosphere (TOA was computed on 2.5° longitude-latitude resolution for the 14-year period from 1984 to 1997, using a radiative transfer model with long-term climatological data from the International Satellite Cloud Climatology Project (ISCCP-D2 supplemented by data from the National Centers for Environmental Prediction – National Center for Atmospheric Research (NCEP-NCAR Global Reanalysis project, and other global data bases such as TIROS Operational Vertical Sounder (TOVS and Global Aerosol Data Set (GADS. The model radiative fluxes at TOA were validated against Earth Radiation Budget Experiment (ERBE S4 scanner satellite data (1985–1989. The model is able to predict the seasonal and geographical variation of SW TOA fluxes. On a mean annual and global basis, the model is in very good agreement with ERBE, overestimating the outgoing SW radiation at TOA (OSR by 0.93 Wm-2 (or by 0.92%, within the ERBE uncertainties. At pixel level, the OSR differences between model and ERBE are mostly within ±10 Wm-2, with ±5 Wm-2 over extended regions, while there exist some geographic areas with differences of up to 40 Wm-2, associated with uncertainties in cloud properties and surface albedo. The 14-year average model results give a planetary albedo equal to 29.6% and a TOA OSR flux of 101.2 Wm-2. A significant linearly decreasing trend in OSR and planetary albedo was found, equal to 2.3 Wm-2 and 0.6% (in absolute values, respectively, over the 14-year period (from January 1984 to December 1997, indicating an increasing solar planetary warming. This planetary SW radiative heating occurs in the tropical and sub-tropical areas (20° S–20° N, with clouds being the most likely cause. The computed global mean OSR anomaly ranges within ±4 Wm-2, with signals from El Niño and La Niña events or Pinatubo eruption, whereas significant negative OSR anomalies, starting from year 1992, are also

  13. Ideas for Testing of Planetary Gear Sets of Automotive Transmissions

    Directory of Open Access Journals (Sweden)

    Achtenová Gabriela

    2017-06-01

    Full Text Available The article describes the concept of modular stand, where is possible to provide tests of gear pairs with fixed axes from mechanical automotive gearboxes, as well as tests of separate planetary sets from automatic gearboxes. Special attention in the article will be paid to the variant dedicated for testing of planetary gear sets. This variant is particularly interesting because: 1 it is rarely described in the literature, and 2 this topology allows big simplification with respect to testing of standard gearwheels. In the planetary closed-loop stand it is possible to directly link two identical planetary sets. Without any bracing flange or other connecting clutches, shafts or gear sets, just two planetary sets face-to-face will be assembled and connected to the electric motor.

  14. Planetary Landscape Geography

    Science.gov (United States)

    Hargitai, H.

    building Lunar or Martian bases. Factors of this category are the presence of water, 24 h communication oppor- tunity with Earth, radio noise free sky, radiation, temperature etc conditions. Since the emergence of the discipline of astrobiology, potentially habitable niches - and espe- cially the so far undiscovered de facto inhabited niches - make very high value of a given landscape. CONCLUSION As we have closer touch with planetary surfaces other than our, and as human (and manned) exploration of the Solar System will again be in the agenda, in addition to physical geographic or geologic factors, new ones: economical, cultural, aesthetic and geofactors together will determine the value of a certain landscape in a given area. Its study will be more geographic than geologic. The above listed ele- ments can be important when chosing a base or landing site on any planetary body. The landscape values can be merged in a GIS system and this way we can more ea- sity determine not only landcape types but also the optimal landing sites for future missions. References [1] Mezõsi , G.: A földrajzi táj (geographic landscape), in: Általános ter- mészerföldrajz, Budapest, 1993. pp 807-818. [2] Baker, V. R.: Extraterrestrial Geo- morphology: An Introduction. Geomorphology 37 (2001) pp 175-178. [3] Jakucs, L.: A földrajzi burok kozmogén és endogén dinamikája (Endogenic and Cosmogenic Dy- namics of the Geospheres). JATEPress, 1997. 3

  15. Influence of Planetary Protection Guidelines on Waste Management Operations

    Science.gov (United States)

    Hogan, John A.; Fisher, John W.; Levri, Julie A.; Wignarajah, Kanapathipi; Race, Margaret S.; Stabekis, Perry D.; Rummel, John D.

    2005-01-01

    Newly outlined missions in the Space Exploration Initiative include extended human habitation on Mars. During these missions, large amounts of waste materials will be generated in solid, liquid and gaseous form. Returning these wastes to Earth will be extremely costly, and will therefore likely remain on Mars. Untreated, these wastes are a reservoir of live/dead organisms and molecules considered to be "biomarkers" i.e., indicators of life). If released to the planetary surface, these materials can potentially confound exobiology experiments and disrupt Martian ecology indefinitely (if existent). Waste management systems must therefore be specifically designed to control release of problematic materials both during the active phase of the mission, and for any specified post-mission duration. To effectively develop waste management requirements for Mars missions, planetary protection guidelines must first be established. While previous policies for Apollo lunar missions exist, it is anticipated that the increased probability of finding evidence of life on Mars, as well as the lengthy mission durations will initially lead to more conservative planetary protection measures. To facilitate the development of overall requirements for both waste management and planetary protection for future missions, a workshop was conducted to identify how these two areas interface, and to establish a preliminary set of planetary protection guidelines that address waste management operations. This paper provides background regarding past and current planetary protection and waste management issues, and their interactions. A summary of the recommended planetary protection guidelines, anticipated ramifications and research needs for waste management system design for both forward (Mars) and backward (Earth) contamination is also provided.

  16. Radiation Pressure Measurements on Micron-Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Witherow, W. K.; West, E. A.; Gallagher, D. L.; Adrian, M. L.; Fishman, G. J.; Tankosic, D.; LeClair, A.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400 microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.

  17. Elpasolite Planetary Ice and Composition Spectrometer (EPICS): A Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary Science

    Science.gov (United States)

    Stonehill, L. C.; Coupland, D. D. S.; Dallmann, N. A.; Feldman, W. C.; Mesick, K.; Nowicki, S.; Storms, S.

    2017-12-01

    The Elpasolite Planetary Ice and Composition Spectrometer (EPICS) is an innovative, low-resource gamma-ray and neutron spectrometer for planetary science missions, enabled by new scintillator and photodetector technologies. Neutrons and gamma rays are produced by cosmic ray interactions with planetary bodies and their subsequent interactions with the near-surface materials produce distinctive energy spectra. Measuring these spectra reveals details of the planetary near-surface composition that are not accessible through any other phenomenology. EPICS will be the first planetary science instrument to fully integrate the neutron and gamma-ray spectrometers. This integration is enabled by the elpasolite family of scintillators that offer gamma-ray spectroscopy energy resolutions as good as 3% FWHM at 662 keV, thermal neutron sensitivity, and the ability to distinguish gamma-ray and neutron signals via pulse shape differences. This new detection technology will significantly reduce size, weight, and power (SWaP) while providing similar neutron performance and improved gamma energy resolution compared to previous scintillator instruments, and the ability to monitor the cosmic-ray source term. EPICS will detect scintillation light with silicon photomultipliers rather than traditional photomultiplier tubes, offering dramatic additional SWaP reduction. EPICS is under development with Los Alamos National Laboratory internal research and development funding. Here we report on the EPICS design, provide an update on the current status of the EPICS development, and discuss the expected sensitivity and performance of EPICS in several potential missions to airless bodies.

  18. The impacts of urban surface characteristics on radiation balance and meteorological variables in the boundary layer around Beijing in summertime

    Science.gov (United States)

    Liu, Ruiting; Han, Zhiwei; Wu, Jian; Hu, Yonghong; Li, Jiawei

    2017-11-01

    In this study, some key geometric and thermal parameters derived from recent field and satellite observations in Beijing were collected and incorporated into WRF-UCM (Weather Research and Forecasting) model instead of previous default ones. A series of sensitivity model simulations were conducted to investigate the influences of these parameters on radiation balance, meteorological variables, turbulence kinetic energy (TKE), as well as planetary boundary layer height (PBLH) in regions around Beijing in summer 2014. Model validation demonstrated that the updated parameters represented urban surface characteristics more realistically and the simulations of meteorological variables were evidently improved to be closer to observations than the default parameters. The increase in building height tended to increase and slightly decrease surface air temperature at 2 m (T2) at night and around noon, respectively, and to reduce wind speed at 10 m (WS10) through a day. The increase in road width led to significant decreases in T2 and WS10 through the whole day, with the maximum changes in early morning and in evening, respectively. Both lower surface albedo and inclusion of anthropogenic heat (AH) resulted in increases in T2 and WS10 over the day, with stronger influence from AH. The vertical extension of the impact of urban surface parameters was mainly confined within 300 m at night and reached as high as 1600 m during daytime. The increase in building height tended to increase TKE and PBLH and the TKE increase was larger at night than during daytime due to enhancements of both mechanical and buoyant productions. The increase in road width generally reduced TKE and PBLH except for a few hours in the afternoon. The lower surface albedo and the presence of AH consistently resulted in increases of TKE and PBLH through both day and night. The increase in building height induced a slight divergence by day and a notable convergence at night, whereas the increase in road width

  19. Reconfigurable Autonomy for Future Planetary Rovers

    Science.gov (United States)

    Burroughes, Guy

    Extra-terrestrial Planetary rover systems are uniquely remote, placing constraints in regard to communication, environmental uncertainty, and limited physical resources, and requiring a high level of fault tolerance and resistance to hardware degradation. This thesis presents a novel self-reconfiguring autonomous software architecture designed to meet the needs of extraterrestrial planetary environments. At runtime it can safely reconfigure low-level control systems, high-level decisional autonomy systems, and managed software architecture. The architecture can perform automatic Verification and Validation of self-reconfiguration at run-time, and enables a system to be self-optimising, self-protecting, and self-healing. A novel self-monitoring system, which is non-invasive, efficient, tunable, and autonomously deploying, is also presented. The architecture was validated through the use-case of a highly autonomous extra-terrestrial planetary exploration rover. Three major forms of reconfiguration were demonstrated and tested: first, high level adjustment of system internal architecture and goal; second, software module modification; and third, low level alteration of hardware control in response to degradation of hardware and environmental change. The architecture was demonstrated to be robust and effective in a Mars sample return mission use-case testing the operational aspects of a novel, reconfigurable guidance, navigation, and control system for a planetary rover, all operating in concert through a scenario that required reconfiguration of all elements of the system.

  20. The energy balance of a plasma in partial local thermodynamic equilibrium

    NARCIS (Netherlands)

    Kroesen, G.M.W.; Schram, D.C.; Timmermans, C.J.; de Haas, J.C.M.

    1990-01-01

    The energy balance for electrons and heavy particles constituting a plasma in partial local thermodynamic equilibrium is derived. The formulation of the energy balance used allows for evaluation of the source terms without knowledge of the particle and radiation transport situation, since most of

  1. Request for Funding for the 2016 Air & Waste Management Association Visibility Conference on Atmospheric Optics:Aerosols, Visibility, and the Radiative Balance

    International Nuclear Information System (INIS)

    Eatough, Delbert

    2016-01-01

    This international conference will provide a technical forum on advances in the scientific understanding of the effects of aerosols on urban, regional, continental, and global-scale haze and the radiative balance. The conference will take a multipronged approach and address scientific topics (e.g., related to measurements, modeling, etc.) as well as regulatory and policy issues. There will be sessions on black and brown carbon, as recent research has shown the importance of these particles for radiative forcing. In addition, there will be sessions related to the synergistic and increasing concerns of the effects of atmospheric nitrogen and carbonaceous material on haze, climate change, and nitrogen deposition on ecosystems. Conference learning will be enhanced with a half day excursion and hikes in Grand Teton National Park and a Night Sky Program.

  2. Request for Funding for the 2016 Air & Waste Management Association Visibility Conference on Atmospheric Optics:Aerosols, Visibility, and the Radiative Balance

    Energy Technology Data Exchange (ETDEWEB)

    Eatough, Delbert [Brigham Young Univ., Provo, UT (United States)

    2016-06-01

    This international conference will provide a technical forum on advances in the scientific understanding of the effects of aerosols on urban, regional, continental, and global-scale haze and the radiative balance. The conference will take a multipronged approach and address scientific topics (e.g., related to measurements, modeling, etc.) as well as regulatory and policy issues. There will be sessions on black and brown carbon, as recent research has shown the importance of these particles for radiative forcing. In addition, there will be sessions related to the synergistic and increasing concerns of the effects of atmospheric nitrogen and carbonaceous material on haze, climate change, and nitrogen deposition on ecosystems. Conference learning will be enhanced with a half day excursion and hikes in Grand Teton National Park and a Night Sky Program.

  3. Evolution of planetary nebula nuclei

    International Nuclear Information System (INIS)

    Shaw, R.A.

    1985-01-01

    The evolution of planetary nebula nuclei (PNNs) is examined with the aid of the most recent available stellar evolution calculations and new observations of these objects. Their expected distribution in the log L-log T plane is calculated based upon the stellar evolutionary models of Paczynski, Schoenberner and Iben, the initial mass function derived by Miller and Scalo, and various assumptions concerning mass loss during post-main sequence evolution. The distribution is found to be insensitive both to the assumed range of main-sequence progenitor mass and to reasonable variations in the age and the star forming history of the galactic disk. Rather, the distribution is determined by the strong dependence of the rate of stellar evolution upon core mass, the steepness of the initial mass function, and to a lesser extent the finite lifetime of an observable planetary nebula. The theoretical distributions are rather different than any of those inferred from earlier observations. Possible observational selection effects that may be responsible are examined, as well as the intrinsic uncertainties associated with the theoretical model predictions. An extensive photometric and smaller photographic survey of southern hemisphere planetary nebulae (PNs) is presented

  4. Ground-based simulations of cosmic ray heavy ion interactions in spacecraft and planetary habitat shielding materials

    Science.gov (United States)

    Miller, J.; Zeitlin, C.; Heilbronn, L.; Borak, T.; Carter, T.; Frankel, K. A.; Fukumura, A.; Murakami, T.; Rademacher, S. E.; Schimmerling, W.; hide

    1998-01-01

    This paper surveys some recent accelerator-based measurements of the nuclear fragmentation of high energy nuclei in shielding and tissue-equivalent materials. These data are needed to make accurate predictions of the radiation field produced at depth in spacecraft and planetary habitat shielding materials and in the human body by heavy charged particles in the galactic cosmic radiation. Projectile-target combinations include 1 GeV/nucleon 56Fe incident on aluminum and graphite and 600 MeV/nucleon 56Fe and 290 MeV/nucleon 12C on polyethylene. We present examples of the dependence of fragmentation on material type and thickness, of a comparison between data and a fragmentation model, and of multiple fragments produced along the beam axis.

  5. Design Tools for Cost-Effective Implementation of Planetary Protection Requirements

    Science.gov (United States)

    Hamlin, Louise; Belz, Andrea; Evans, Michael; Kastner, Jason; Satter, Celeste; Spry, Andy

    2006-01-01

    Since the Viking missions to Mars in the 1970s, accounting for the costs associated with planetary protection implementation has not been done systematically during early project formulation phases, leading to unanticipated costs during subsequent implementation phases of flight projects. The simultaneous development of more stringent planetary protection requirements, resulting from new knowledge about the limits of life on Earth, together with current plans to conduct life-detection experiments on a number of different solar system target bodies motivates a systematic approach to integrating planetary protection requirements and mission design. A current development effort at NASA's Jet Propulsion Laboratory is aimed at integrating planetary protection requirements more fully into the early phases of mission architecture formulation and at developing tools to more rigorously predict associated cost and schedule impacts of architecture options chosen to meet planetary protection requirements.

  6. Planetary Nomenclature: An Overview and Update for 2017

    Science.gov (United States)

    Gaither, Tenielle; Hayward, Rose; IAU Working GroupPlanetary System Nomenclature

    2017-10-01

    The task of naming planetary surface features, rings, and natural satellites is managed by the International Astronomical Union’s (IAU) Working Group for Planetary System Nomenclature (WGPSN). There are currently 15,361 IAU-approved surface feature names on 41 planetary bodies, including moons and asteroids. The members of the WGPSN and its task groups have worked since the early 1970s to provide a clear, unambiguous system of planetary nomenclature that represents cultures and countries from all regions of Earth. WGPSN members include Rita Schulz (Chair) and 9 other members representing countries around the globe. The participation of knowledgeable scientists and experts in this process is vital to its success of the IAU WGPSN . Planetary nomenclature is a tool used to uniquely identify features on the surfaces of planets or satellites so they can be located, described, and discussed in publications, including peer-review journals, maps and conference presentations. Approved names are listed in the Transactions of the IAU and on the Gazetteer of Planetary Nomenclature website. Any names currently in use that are not listed the Gazetteer are not official. Planetary names must adhere to rules and conventions established by the IAU WGPSN (see http://planetarynames.wr.usgs.gov/Page/Rules for the complete list). The gazetteer includes an online Name Request Form (http://planetarynames.wr.usgs.gov/FeatureNameRequest) that can be used by members of the professional science community. Name requests are first reviewed by one of six task groups (Mercury, Venus, Moon, Mars, Outer Solar System, and Small Bodies). After a task group has reviewed a proposal, it is submitted to the WGPSN. Allow four to six weeks for the review and approval process. Upon WGPSN approval, names are considered formally approved and it is then appropriate to use them in publications. Approved names are immediately entered into the database and shown on the website. Questions about the nomenclature

  7. Magnetic Fields of Extrasolar Planets: Planetary Interiors and Habitability

    Science.gov (United States)

    Lazio, T. Joseph

    2018-06-01

    Ground-based observations showed that Jupiter's radio emission is linked to its planetary-scale magnetic field, and subsequent spacecraft observations have shown that most planets, and some moons, have or had a global magnetic field. Generated by internal dynamos, magnetic fields are one of the few remote sensing means of constraining the properties of planetary interiors. For the Earth, its magnetic field has been speculated to be partially responsible for its habitability, and knowledge of an extrasolar planet's magnetic field may be necessary to assess its habitability. The radio emission from Jupiter and other solar system planets is produced by an electron cyclotron maser, and detections of extrasolar planetary electron cyclotron masers will enable measurements of extrasolar planetary magnetic fields. Based on experience from the solar system, such observations will almost certainly require space-based observations, but they will also be guided by on-going and near-future ground-based observations.This work has benefited from the discussion and participants of the W. M. Keck Institute of Space Studies "Planetary Magnetic Fields: Planetary Interiors and Habitability" and content within a white paper submitted to the National Academy of Science Committee on Exoplanet Science Strategy. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  8. Balancing requirements for radioactive waste management and radiation protection

    International Nuclear Information System (INIS)

    Lafuma, J.; Lefevre, J.

    1985-01-01

    The authors recall the principles of radiation protection and their application to radioactive waste management. The dose limitation system applies to every stage in management. The accepted risk limits should be compared with the level of risk from other sources, particularly from natural radiation. The uncertainties associated with long-term estimates should not lead to unrealistic requirements. The optimum rules are to be obtained by discussion among those responsible for radiation protection, nuclear safety and radioactive waste management. Satisfactory, applicable rules can be worked out in the present state of the art [fr

  9. Laboratory simulations of planetary surfaces: Understanding regolith physical properties from remote photopolarimetric observations

    Science.gov (United States)

    Nelson, Robert M.; Boryta, Mark D.; Hapke, Bruce W.; Manatt, Kenneth S.; Shkuratov, Yuriy; Psarev, V.; Vandervoort, Kurt; Kroner, Desire; Nebedum, Adaze; Vides, Christina L.; Quiñones, John

    2018-03-01

    We present reflectance and polarization phase curve measurements of highly reflective planetary regolith analogues having physical characteristics expected on atmosphereless solar system bodies (ASSBs) such as a eucritic asteroids or icy satellites. We used a goniometric photopolarimeter (GPP) of novel design to study thirteen well-sorted particle size fractions of aluminum oxide (Al2O3). The sample suite included particle sizes larger than, approximately equal to, and smaller than the wavelength of the incident monochromatic radiation (λ = 635 nm). The observed phase angle, α, was 0.056 o ∼95%). The incident radiation has a very high probability of being multiply scattered before being backscattered toward the incident direction or ultimately absorbed. The five smallest particle sizes exhibited extremely high void space (> ∼95%). The reflectance phase curves for all particle size fractions show a pronounced non-linear reflectance increase with decreasing phase angle at α∼ ∼1 we detect no polarization. This polarization behavior is distinct from that observed in low albedo solar system objects such as the Moon and asteroids and for absorbing materials in the laboratory. We suggest this behavior arises because photons that are backscattered have a high probability of having interacted with two or more particles, thus giving rise to the CB process. These results may explain the unusual negative polarization behavior observed near small phase angles reported for several decades on highly reflective ASSBs such as the asteroids 44 Nysa, 64 Angelina and the Galilean satellites Io, Europa and Ganymede. Our results suggest these ASSB regoliths scatter electromagnetic radiation as if they were extremely fine grained with void space > ∼95%, and grain sizes of the order geo-engineering, particularly to suggestions that earth's radiation balance can be modified by injecting Al2O3 particulates into the stratosphere thereby offsetting the effect of anthropogenic

  10. Solar energy and global heat balance of a city

    Energy Technology Data Exchange (ETDEWEB)

    Roulet, Claude-Alain [Ecole Polytechnique Federale, Lab. d' Energie Solaire et de Physique du Batiment, Lausanne (Switzerland)

    2001-07-01

    The global energy balance of a city involves numerous energy flows and is rather complex. It includes, among others, the absorbed solar radiation and the energy fuels on one hand, and the heat loss to the environment --- by radiation, convection and evaporation --- on the other hand. This balance generally results in a temperature in the town that is slightly higher than in the surrounding country. Using solar energy saves imported fuels on one hand, but increases the absorption of solar radiation on the other hand. Simple, steady state models are used to assess the change of heat released to the environment when replacing the use of classical fuels by solar powered plants, on both the global and city scale. The conclusion is that, in most cases, this will reduce the heat released to the environment. The exception is cooling, for which a good solar alternative does not exist today. (Author)

  11. Interannual and Decadal Variations of Planetary Wave Activity, Stratospheric Cooling, and Northern Hemisphere Annular Mode.

    Science.gov (United States)

    Hu, Yongyun; Kit Tung, Ka

    2002-07-01

    Using NCEP-NCAR 51-yr reanalysis data, the interannual and decadal variations of planetary wave activity and its relationship to stratospheric cooling, and the Northern Hemisphere Annular mode (NAM), are studied. It is found that winter stratospheric polar temperature is highly correlated on a year-to-year basis with the Eliassen-Palm (E-P) wave flux from the troposphere, implying a dynamical control of the former by the latter, as often suggested. Greater (lower) wave activity from the troposphere implies larger (smaller) poleward heat flux into the polar region, which leads to warmer (colder) polar temperature. A similar highly correlated antiphase relationship holds for E-P flux divergence and the strength of the polar vortex in the stratosphere. It is tempting to extrapolate these relationships found for interannual timescales to explain the recent stratospheric polar cooling trend in the past few decades as caused by decreased wave activity in the polar region. This speculation is not supported by the data. On timescales of decades the cooling trend is not correlated with the trend in planetary wave activity. In fact, it is found that planetary wave amplitude, E-P flux, and E-P flux convergence all show little statistical evidence of decrease in the past 51 yr, while the stratosphere is experiencing a cooling trend and the NAM index has a positive trend during the past 30 yr. This suggests that the trends in the winter polar temperature and the NAM index can reasonably be attributed to the radiative cooling of the stratosphere, due possibly to increasing greenhouse gases and ozone depletion. It is further shown that the positive trend of the NAM index in the past few decades is not through the inhibition of upward planetary wave propagation from the troposphere to the stratosphere, as previously suggested.

  12. Radiation Pressure Measurements on Micron Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P.D.; Spann, J. F.; Tankosic, D.; Witherow, W. K.; LeClair, A.; West, E.; Sheldon, R.; Gallagher, D. L.; Adrian, M. L.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2 micron to 6.82 micron range and irradiating them from above with laser radiation focused to beam-widths of approx. 175-400 micron, at ambient pressures approx. 10(exp -3) to 10(exp -4) torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of silica and the corresponding extinction and scattering efficiencies.

  13. Relation between radius and expansion velocity in planetary nebulae

    International Nuclear Information System (INIS)

    Chu, Y.H.; Kwitter, K.B.; Kaler, J.B.

    1984-01-01

    The expansion velocity-radius (R-V) relation for planetary nebulae is examined using the existing measurements of expansion velocities and recent calculations of radii. It is found that some of the previously alleged R-V relations for PN are not convincingly established. The scatter in the R-V plots may be due largely to stratification of ions in individual nebulae and to heterogeneity in the planetary nebula population. In addition, from new echelle/CCD observations of planetary nebulae, it is found that spatial information is essential in deriving the internal kinematic properties. Future investigations of R-V relations should be pursued separately for groups of planetaries with similar physical properties, and they should employ observations of appropriate low excitation lines in order to measure the expansion velocity at the surface of the nebula. 26 references

  14. Planetary Sciences Literature - Access and Discovery

    Science.gov (United States)

    Henneken, Edwin A.; ADS Team

    2017-10-01

    The NASA Astrophysics Data System (ADS) has been around for over 2 decades, helping professional astronomers and planetary scientists navigate, without charge, through the increasingly complex environment of scholarly publications. As boundaries between disciplines dissolve and expand, the ADS provides powerful tools to help researchers discover useful information efficiently. In its new form, code-named ADS Bumblebee (https://ui.adsabs.harvard.edu), it may very well answer questions you didn't know you had! While the classic ADS (http://ads.harvard.edu) focuses mostly on searching basic metadata (author, title and abstract), today's ADS is best described as a an "aggregator" of scholarly resources relevant to the needs of researchers in astronomy and planetary sciences, and providing a discovery environment on top of this. In addition to indexing content from a variety of publishers, data and software archives, the ADS enriches its records by text-mining and indexing the full-text articles (about 4.7 million in total, with 130,000 from planetary science journals), enriching its metadata through the extraction of citations and acknowledgments. Recent technology developments include a new Application Programming Interface (API), a new user interface featuring a variety of visualizations and bibliometric analysis, and integration with ORCID services to support paper claiming. The new ADS provides powerful tools to help you find review papers on a given subject, prolific authors working on a subject and who they are collaborating with (within and outside their group) and papers most read by by people who read recent papers on the topic of your interest. These are just a couple of examples of the capabilities of the new ADS. We currently index most journals covering the planetary sciences and we are striving to include those journals most frequently cited by planetary science publications. The ADS is operated by the Smithsonian Astrophysical Observatory under NASA

  15. The planetary scientist's companion

    CERN Document Server

    Lodders, Katharina

    1998-01-01

    A comprehensive and practical book of facts and data about the Sun, planets, asteroids, comets, meteorites, the Kuiper belt and Centaur objects in our solar system. Also covered are properties of nearby stars, the interstellar medium, and extra-solar planetary systems.

  16. Planetary Boundaries: Exploring the Safe Operating Space for Humanity

    DEFF Research Database (Denmark)

    Richardson, Katherine; Rockström, Johan; Steffen, Will

    2009-01-01

    boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance...... and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure...

  17. UNSTABLE PLANETARY SYSTEMS EMERGING OUT OF GAS DISKS

    International Nuclear Information System (INIS)

    Matsumura, Soko; Thommes, Edward W.; Chatterjee, Sourav; Rasio, Frederic A.

    2010-01-01

    The discovery of over 400 extrasolar planets allows us to statistically test our understanding of the formation and dynamics of planetary systems via numerical simulations. Traditional N-body simulations of multiple-planet systems without gas disks have successfully reproduced the eccentricity (e) distribution of the observed systems by assuming that the planetary systems are relatively closely packed when the gas disk dissipates, so that they become dynamically unstable within the stellar lifetime. However, such studies cannot explain the small semimajor axes a of extrasolar planetary systems, if planets are formed, as the standard planet formation theory suggests, beyond the ice line. In this paper, we numerically study the evolution of three-planet systems in dissipating gas disks, and constrain the initial conditions that reproduce the observed a and e distributions simultaneously. We adopt initial conditions that are motivated by the standard planet formation theory, and self-consistently simulate the disk evolution and planet migration, by using a hybrid N-body and one-dimensional gas disk code. We also take into account eccentricity damping, and investigate the effect of saturation of corotation resonances on the evolution of planetary systems. We find that the a distribution is largely determined in a gas disk, while the e distribution is determined after the disk dissipation. We also find that there may be an optimum disk mass which leads to the observed a-e distribution. Our simulations generate a larger fraction of planetary systems trapped in mean-motion resonances (MMRs) than the observations, indicating that the disk's perturbation to the planetary orbits may be important to explain the observed rate of MMRs. We also find a much lower occurrence of planets on retrograde orbits than the current observations of close-in planets suggest.

  18. Miniaturisation of imaging spectrometer for planetary exploration

    Science.gov (United States)

    Drossart, Pierre; Sémery, Alain; Réess, Jean-Michel; Combes, Michel

    2017-11-01

    Future planetary exploration on telluric or giant planets will need a new kind of instrumentation combining imaging and spectroscopy at high spectral resolution to achieve new scientific measurements, in particular for atmospheric studies in nadir configuration. We present here a study of a Fourier Transform heterodyne spectrometer, which can achieve these objectives, in the visible or infrared. The system is composed of a Michelson interferometer, whose mirrors have been replaced by gratings, a configuration studied in the early days of Fourier Transform spectroscopy, but only recently reused for space instrumentation, with the availability of large infrared mosaics. A complete study of an instrument is underway, with optical and electronic tests, as well as data processing analysis. This instrument will be proposed for future planetary missions, including ESA/Bepi Colombo Mercury Planetary Orbiter or Earth orbiting platforms.

  19. Ultraviolet Radiation in the Solar System

    CERN Document Server

    Vázquez, M

    2006-01-01

    UV radiation is an important part in the electromagnetic spectrum since the energy of the photons is great enough to produce important chemical reactions in the atmospheres of planets and satellites of our Solar System, thereby affecting the transmission of this radiation to the ground and its physical properties. Scientists have used different techniques (balloons and rockets) to access to the information contained in this radiation, but the pioneering of this new frontier has not been free of dangers. The Sun is our main source of UV radiation and its description occupies the first two chapters of the book. The Earth is the only known location where life exists in a planetary system and therefore where the interaction of living organism with UV radiation can be tested through different epochs and on distinct species. The development of the human technology has affected the natural shield of ozone that protects complex lifeforms against damaging UV irradiation. The formation of the ozone hole and its consequ...

  20. The chemical composition of three planetary nebulae in the Magellanic clouds

    International Nuclear Information System (INIS)

    Dufour, R.J.; Killen, R.M.

    1977-01-01

    Emission-line intensities in the planetary nebulae Henize 67 in the Small Magellanic Cloud (SMC) and Henize 97 and 153 in the LMC along with the small SMC H II regions Henize 9, 61, and 81 were measured from photographic image-tube spectra taken with the 1.5 m telescope at Cerro Tololo. The relative abundances of H, He, N, O, Ne, S, and Ar in the nebulae were estimated and compared with the compositions of galactic planetary nebulae and previously studied H II regions in the Clouds. The results show that (1) the N/O ratios in the planetary nebulae are substantially higher than found in the H II regions of each Cloud; (2) He/H approx. = 0.18 in the SMC planetary nebula, but seems normal (approx.0.10) in the two LMC planetaries; and (3) the compositions of the three small SMC H II regions are similar to that of larger SMC H II regions studied previously. It is concluded that the N/H values in the shells of planetary nebulae may not depend on the metal content of the progenitor star as much as recent theoretical models suggest and that the N content of the gas in the Magellanic Clouds arises primarily from sources other than planetary nebulae

  1. LBT observations of the HR8799 planetary system

    Science.gov (United States)

    Mesa, D.; Arcidiacono, C.; Claudi, R. U.; Desidera, S.; Esposito, S.; Gratton, R.; Masciadri, E.

    2013-09-01

    We present here observations of the HR8799 planetary system performed in H and Ks band exploiting the AO system at the Large Binocular Telescope and the PISCES camera. Thanks to the excellent performence of the instrument we were able to detect for the first time the inner known planet of the system (HR8799) in the H band. Precise photometric and astrometric measures have been taken for all the four planets. Further, exploiting ours and previous astrometric results, we were able to put some limits on the planetary orbits of the four planets. The analysis of the dinamical stability of the system seems to show lower planetary masses than the ones adopted until now.

  2. Advances in Planetary Protection at the Deep Space Gateway

    Science.gov (United States)

    Spry, J. A.; Siegel, B.; Race, M.; Rummel, J. D.; Pugel, D. E.; Groen, F. J.; Kminek, G.; Conley, C. A.; Carosso, N. J.

    2018-02-01

    Planetary protection knowledge gaps that can be addressed by science performed at the Deep Space Gateway in the areas of human health and performance, space biology, and planetary sciences that enable future exploration in deep space, at Mars, and other targets.

  3. Reconstruction and visualization of planetary nebulae.

    Science.gov (United States)

    Magnor, Marcus; Kindlmann, Gordon; Hansen, Charles; Duric, Neb

    2005-01-01

    From our terrestrially confined viewpoint, the actual three-dimensional shape of distant astronomical objects is, in general, very challenging to determine. For one class of astronomical objects, however, spatial structure can be recovered from conventional 2D images alone. So-called planetary nebulae (PNe) exhibit pronounced symmetry characteristics that come about due to fundamental physical processes. Making use of this symmetry constraint, we present a technique to automatically recover the axisymmetric structure of many planetary nebulae from photographs. With GPU-based volume rendering driving a nonlinear optimization, we estimate the nebula's local emission density as a function of its radial and axial coordinates and we recover the orientation of the nebula relative to Earth. The optimization refines the nebula model and its orientation by minimizing the differences between the rendered image and the original astronomical image. The resulting model allows creating realistic 3D visualizations of these nebulae, for example, for planetarium shows and other educational purposes. In addition, the recovered spatial distribution of the emissive gas can help astrophysicists gain deeper insight into the formation processes of planetary nebulae.

  4. The Africa Initiative for Planetary and Space Sciences

    Science.gov (United States)

    Baratoux, D.; Chennaoui-Aoudjehane, H.; Gibson, R.; Lamali, A.; Reimold, W. U.; Selorm Sepah, M.; Chabou, M. C.; Habarulema, J. B.; Jessell, M.; Mogessie, A.; Benkhaldoun, Z.; Nkhonjera, E.; Mukosi, N. C.; Kaire, M.; Rochette, P.; Sickafoose, A.; Martínez-Frías, J.; Hofmann, A.; Folco, L.; Rossi, A. P.; Faye, G.; Kolenberg, K.; Tekle, K.; Belhai, D.; Elyajouri, M.; Koeberl, C.; Abdeem, M.

    2017-12-01

    Research groups in Planetary and Space Sciences (PSS) are now emerging in Africa, but remain few, scattered and underfunded. It is our conviction that the exclusion of 20% of the world's population from taking part in the fascinating discoveries about our solar system impoverishes global science. The benefits of a coordinated PSS program for Africa's youth have motivated a call for international support and investment [1] into an Africa Initiative for Planetary and Space Sciences. At the time of writing, the call has been endorsed by 230 scientists and 19 institutions or international organizations (follow the map of endorsements on https://africapss.org). More than 70 African Planetary scientists have already joined the initiative and about 150 researchers in non-African countries are ready to participate in research and in capacitity building of PSS programs in Africa. We will briefly review in this presentation the status of PSS in Africa [2] and illustrate some of the major achievements of African Planetary and Space scientists, including the search for meteorites or impact craters, the observations of exoplanets, and space weather investigations. We will then discuss a road map for its expansion, with an emphasis on the role that planetary and space scientists can play to support scientific and economic development in Africa. The initiative is conceived as a network of projects with Principal Investigators based in Africa. A Steering Committee is being constituted to coordinate these efforts and contribute to fund-raising and identification of potential private and public sponsors. The scientific strategy of each group within the network will be developed in cooperation with international experts, taking into account the local expertise, available equipment and facilities, and the priority needs to achieve well-identified scientific goals. Several founding events will be organized in 2018 in several African research centers and higher-education institutions to

  5. HESS Opinions: A planetary boundary on freshwater use is misleading

    Science.gov (United States)

    Heistermann, Maik

    2017-07-01

    In 2009, a group of prominent Earth scientists introduced the planetary boundaries (PB) framework: they suggested nine global control variables, and defined corresponding thresholds which, if crossed, could generate unacceptable environmental change. The concept builds on systems theory, and views Earth as a complex adaptive system in which anthropogenic disturbances may trigger non-linear, abrupt, and irreversible changes at the global scale, and push the Earth system outside the stable environmental state of the Holocene. While the idea has been remarkably successful in both science and policy circles, it has also raised fundamental concerns, as the majority of suggested processes and their corresponding planetary boundaries do not operate at the global scale, and thus apparently lack the potential to trigger abrupt planetary changes. This paper picks up the debate with specific regard to the planetary boundary on global freshwater use. While the bio-physical impacts of excessive water consumption are typically confined to the river basin scale, the PB proponents argue that water-induced environmental disasters could build up to planetary-scale feedbacks and system failures. So far, however, no evidence has been presented to corroborate that hypothesis. Furthermore, no coherent approach has been presented to what extent a planetary threshold value could reflect the risk of regional environmental disaster. To be sure, the PB framework was revised in 2015, extending the planetary freshwater boundary with a set of basin-level boundaries inferred from environmental water flow assumptions. Yet, no new evidence was presented, either with respect to the ability of those basin-level boundaries to reflect the risk of regional regime shifts or with respect to a potential mechanism linking river basins to the planetary scale. So while the idea of a planetary boundary on freshwater use appears intriguing, the line of arguments presented so far remains speculative and

  6. The ionisation balance of C0 to C+4

    International Nuclear Information System (INIS)

    Nussbaumer, H.; Storey, P.J.

    1975-01-01

    The ionisation balance for the ions C 0 -C +4 has been calculated for 10 8 -3 ] 12 and 2 x 10 4 K 5 K. The presence of metastable terms is included in the calculation of the collisional dielectronic recombination and ionisation coefficients. The influence of the observed solar radiation field on the ionisation balance is investigated. Changes in that field do strongly influence the results. (orig.) [de

  7. Radiation versus radiation: nuclear energy in perspective

    International Nuclear Information System (INIS)

    Gonzalez, A.J.; Anderer, J.

    1989-01-01

    This paper seeks to provide a proper perspective on radiation exposures from nuclear energy. Instead of comparing these exposures with other pollutants, natural and man-made, it assesses the radiation doses that result from the human environment and from the entire fuel cycle associated with nuclear generated electricity. It explores radiation versus radiation, not only in terms of absolute levels but, more importantly, of the enormous variability characterizing many radiation sources. The quantitative findings and their implications are meant to contribute to a balanced understanding of the radiological impact of nuclear energy, and so to help to bridge the information gap that is perceived to exist on this issue. The 1988 Unscear report and its seven scientific annexes provide an authoritative and dispassionate factual basis for examining radiation levels from all sources, natural and man-made. It is the main source for this paper. (author)

  8. Planetary protection issues related to human missions to Mars

    Science.gov (United States)

    Debus, A.; Arnould, J.

    2008-09-01

    In accordance with the United Nations Outer Space Treaties [United Nations, Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, UN doc A/RES/34/68, resolution 38/68 of December 1979], currently maintained and promulgated by the Committee on Space Research [COSPAR Planetary Protection Panel, Planetary Protection Policy accepted by the COSPAR Council and Bureau, 20 October 2002, amended 24 March 2005, http://www.cosparhq.org/scistr/PPPolicy.htm], missions exploring the Solar system must meet planetary protection requirements. Planetary protection aims to protect celestial bodies from terrestrial contamination and to protect the Earth environment from potential biological contamination carried by returned samples or space systems that have been in contact with an extraterrestrial environment. From an exobiology perspective, Mars is one of the major targets, and several missions are currently in operation, in transit, or scheduled for its exploration. Some of them include payloads dedicated to the detection of life or traces of life. The next step, over the coming years, will be to return samples from Mars to Earth, with a view to increasing our knowledge in preparation for the first manned mission that is likely to take place within the next few decades. Robotic missions to Mars shall meet planetary protection specifications, currently well documented, and planetary protection programs are implemented in a very reliable manner given that experience in the field spans some 40 years. With regards to sample return missions, a set of stringent requirements has been approved by COSPAR [COSPAR Planetary Protection Panel, Planetary Protection Policy accepted by the COSPAR Council and Bureau, 20 October 2002, amended 24 March 2005, http://www.cosparhq.org/scistr/PPPolicy.htm], and technical challenges must now be overcome in order to preserve the Earth’s biosphere from any eventual contamination risk. In addition to the human dimension of

  9. 75 FR 19661 - NASA Advisory Council; Science Committee; Planetary Protection Subcommittee; Meeting

    Science.gov (United States)

    2010-04-15

    ... includes the following topics: --Review European Space Agency-NASA Coordination on Planetary Protection... Committee; Planetary Protection Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration... (NASA) announces a meeting of the Planetary Protection Subcommittee of the NASA Advisory Council (NAC...

  10. Some results of radiative balance in atmospheres with clouds

    International Nuclear Information System (INIS)

    Anduckia Avila, Juan Carlos; Pelkowski, Joaquin

    2000-01-01

    Vertical profiles of temperature for a semi grey three-Layer atmosphere are established using a radiative equilibrium condition. The approximation contains the greenhouse effect, scattering by clouds in one direction and isotropic diffuse reflection at the planet's surface. Absorption of short- wave radiation is also considered in one of the three layers. Similar models are contained therein

  11. Intermediate Models of Planetary Circulations in the Atmosphere and Ocean.

    Science.gov (United States)

    McWilliams, James C.; Gent, Peter R.

    1980-08-01

    Large-scale extratropical motions (with dimensions comparable to, or somewhat smaller than, the planetary radius) in the atmosphere and ocean exhibit a more restricted range of phenomena than are admissible in the primitive equations for fluid motions, and there have been many previous proposals for simpler, more phenomenologically limited models of these motions. The oldest and most successful of these is the quasi-geostrophic model. An extensive discussion is made of models intermediate between the quasi-geostrophic and primitive ones, some of which have been previously proposed [e.g., the balance equations (BE), where tendencies in the equation for the divergent component of velocity are neglected, or the geostrophic momentum approximation (GM), where ageostrophic accelerations are neglected relative to geostrophic ones] and some of which are derived here. Virtues of these models are assessed in the dual measure of nearly geostrophic momentum balance (i.e., small Rossby number) and approximate frontal structure (i.e., larger along-axis velocities and length scales than their cross-axis counterparts), since one or both of these circumstances is usually characteristic of planetary motions. Consideration is also given to various coordinate transformations, since they can yield simpler expressions for the governing differential equations of the intermediate models. In particular, a new set of coordinates is proposed, isentropic geostrophic coordinates,(IGC), which has the advantage of making implicit the advections due to ageostrophic horizontal and vertical velocities under various approximations. A generalization of quasi-geostrophy is made. named hypo-geostrophy (HG), which is an asymptotic approximation of one higher order accuracy in Rossby number. The governing equations are simplest in IGC for both HG and GM; we name the latter in these coordinates isentropic semi-geostrophy (ISG), in analogy to Hoskins' (1975) semi-geostrophy (SG). HG, GM and BE are, in our

  12. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1978-01-01

    The author's review concentrates on theoretical aspects of dust in planetary nebulae (PN). He considers the questions: how much dust is there is PN; what is its composition; what effects does it have on the ionization structure, on the dynamics of the nebula. (Auth.)

  13. Planetary ring systems properties, structures, and evolution

    CERN Document Server

    Murray, Carl D

    2018-01-01

    Planetary rings are among the most intriguing structures of our solar system and have fascinated generations of astronomers. Collating emerging knowledge in the field, this volume reviews our current understanding of ring systems with reference to the rings of Saturn, Uranus, Neptune, and more. Written by leading experts, the history of ring research and the basics of ring–particle orbits is followed by a review of the known planetary ring systems. All aspects of ring system science are described in detail, including specific dynamical processes, types of structures, thermal properties and their origins, and investigations using computer simulations and laboratory experiments. The concluding chapters discuss the prospects of future missions to planetary rings, the ways in which ring science informs and is informed by the study of other astrophysical disks, and a perspective on the field's future. Researchers of all levels will benefit from this thorough and engaging presentation.

  14. Planetary Space Weather Service: Part of the the Europlanet 2020 Research Infrastructure

    Science.gov (United States)

    Grande, Manuel; Andre, Nicolas

    2016-07-01

    Over the next four years the Europlanet 2020 Research Infrastructure will set up an entirely new European Planetary Space Weather service (PSWS). Europlanet RI is a part of of Horizon 2020 (EPN2020-RI, http://www.europlanet-2020-ri.eu). The Virtual Access Service, WP5 VA1 "Planetary Space Weather Services" will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. VA1 will make five entirely new 'toolkits' accessible to the research community and to industrial partners planning for space missions: a general planetary space weather toolkit, as well as three toolkits dedicated to the following key planetary environments: Mars (in support ExoMars), comets (building on the expected success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUICE mission to be launched in 2022). This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather in the tools and models available within the partner institutes. It will also create a novel event-diary toolkit aiming at predicting and detecting planetary events like meteor showers and impacts. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. So WP10 JRA4 "Planetary Space Weather Services" (PSWS) will provide the additional research and tailoring required to apply them for these purposes. The overall objectives of this Joint Research Aactivities will be to review, test, improve and adapt methods and tools

  15. Balancing Radiation and Contrast Media Dose in Single-Pass Abdominal Multidetector CT: Prospective Evaluation of Image Quality.

    Science.gov (United States)

    Camera, Luigi; Romano, Federica; Liccardo, Immacolata; Liuzzi, Raffaele; Imbriaco, Massimo; Mainenti, Pier Paolo; Pizzuti, Laura Micol; Segreto, Sabrina; Maurea, Simone; Brunetti, Arturo

    2015-11-01

    As both contrast and radiation dose affect the quality of CT images, a constant image quality in abdominal contrast-enhanced multidetector computed tomography (CE-MDCT) could be obtained balancing radiation and contrast media dose according to the age of the patients. Seventy-two (38 Men; 34 women; aged 20-83 years) patients underwent a single-pass abdominal CE-MDCT. Patients were divided into three different age groups: A (20-44 years); B (45-65 years); and C (>65 years). For each group, a different noise index (NI) and contrast media dose (370 mgI/mL) was selected as follows: A (NI, 15; 2.5 mL/kg), B (NI, 12.5; 2 mL/kg), and C (NI, 10; 1.5 mL/kg). Radiation exposure was reported as dose-length product (DLP) in mGy × cm. For quantitative analysis, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated for both the liver (L) and the abdominal aorta (A). Statistical analysis was performed with a one-way analysis of variance. Standard imaging criteria were used for qualitative analysis. Although peak hepatic enhancement was 152 ± 16, 128 ± 12, and 101 ± 14 Hounsfield units (P contrast media dose (mL) administered were 476 ± 147 and 155 ± 27 for group A, 926 ± 291 and 130 ± 16 for group B, and 1981 ± 451 and 106 ± 15 for group C, respectively (P contrast media dose administered to patients of different age. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  16. Interdisciplinary Research Produces Results in the Understanding of Planetary Dunes

    Science.gov (United States)

    Titus, Timothy N.; Hayward, Rosalyn Kay; Bourke, Mary C.

    2010-08-01

    Second International Planetary Dunes Workshop: Planetary Analogs—Integrating Models, Remote Sensing, and Field Data; Alamosa, Colorado, 18-21 May 2010; Dunes and other eolian bed forms are prominent on several planetary bodies in our solar system. Despite 4 decades of study, many questions remain regarding the composition, age, and origins of these features, as well as the climatic conditions under which they formed. Recently acquired data from orbiters and rovers, together with terrestrial analogs and numerical models, are providing new insights into Martian sand dunes, as well as eolian bed forms on other terrestrial planetary bodies (e.g., Titan). As a means of bringing together terrestrial and planetary researchers from diverse backgrounds with the goal of fostering collaborative interdisciplinary research, the U.S. Geological Survey (USGS), the Carl Sagan Center for the Study of Life in the Universe, the Desert Research Institute, and the U.S. National Park Service held a workshop in Colorado. The small group setting facilitated intensive discussion of problems and issues associated with eolian processes on Earth, Mars, and Titan.

  17. Automation and Robotics for space operation and planetary exploration

    Science.gov (United States)

    Montemerlo, Melvin D.

    1990-01-01

    This paper presents a perspective of Automation and Robotics (A&R) research and developments at NASA in terms of its history, its current status, and its future. It covers artificial intelligence, telerobotics and planetary rovers, and it encompasses ground operations, operations in earth orbit, and planetary exploration.

  18. Vibration condition monitoring of planetary gearbox under varying external load

    Energy Technology Data Exchange (ETDEWEB)

    Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

    2009-01-15

    The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

  19. HPS: A space fission power system suitable for near-term, low-cost lunar and planetary bases

    International Nuclear Information System (INIS)

    Houts, M.G.; Poston, D.I.; Ranken, W.A.

    1996-01-01

    Near-term, low-cost space fission power systems can enhance the feasibility and utility of lunar and planetary bases. One such system, the Heatpipe Power System (HPS), is described in this paper. The HPS draws on 40 yr of United States and international experience to enable a system that can be developed in <5 yr at a cost of <$100M. Total HPS mass is <600 kg at 5 kWe and <2000 kg at 50 kWe, assuming that thermoelectric power conversion is used. More advanced power conversion systems could reduce system mass significantly. System mass for planetary surface systems also may be reduced (1) if indigenous material is used for radiation shielding and (2) because of the positive effect of the gravitational field on heatpipe operation. The HPS is virtually non-radioactive at launch and is passively subcritical during all credible launch accidents. Full-system electrically heated testing is possible, and a ground nuclear power test is not needed for flight qualification. Fuel burnup limits are not reached for several decades, thus giving the system long-life potential

  20. Tips and Tools for Teaching Planetary Science

    Science.gov (United States)

    Schneider, N. M.

    2011-10-01

    The poster will describe handson exercises with demonstrations, clicker questions and discussion to demonstrate how to help students understand planets on a deeper conceptual level. We'll also discuss ways to take the latest discoveries beyond "wow" and turn them into teachable moments. The goal is to give modern strategies for teaching planetary science, emphasizing physical concepts and comparative principles. All will be given digital copies of video clips, demonstration descriptions, clicker questions, web links and powerpoint slidesets on recent planetary science discoveries.

  1. Calcium signals in planetary embryos

    Science.gov (United States)

    Morbidelli, Alessandro

    2018-03-01

    The calcium-isotope composition of planetary bodies in the inner Solar System correlates with the masses of such objects. This finding could have implications for our understanding of how the Solar System formed.

  2. Spectrophotometry of Bowen resonance fluorescence lines in three planetary nebulae

    Science.gov (United States)

    O'Dell, C. R.; Miller, Christopher O.

    1992-01-01

    The results are presented of a uniquely complete, carefully reduced set of observations of the O III Bowen fluorescence lines in the planetary nebulae NGC 6210, NGC 7027, and NGC 7662. A detailed comparison with the predictions of radiative excitation verify that some secondary lines are enhanced by selective population by the charge exchange mechanism involving O IV. Charge exchange is most important in NGC 6210, which is of significantly lower ionization than the other nebulae. In addition to the principal Bowen lines arising from Ly-alpha pumping of the O III O1 line, lines arising from pumping of the O3 line are also observed. Comparison of lines produced by O1 and O3 with the theoretical predictions of Neufeld indicate poor agreement; comparison with the theoretical predictions of Harrington show agreement with NGC 7027 and NGC 7662.

  3. Equation of state experiments and theory relevant to planetary modelling

    International Nuclear Information System (INIS)

    Ross, M.; Graboske, H.C. Jr.; Nellis, W.J.

    1981-01-01

    In recent years there have been a number of static and shockwave experiments on the properties of planetary materials. The highest pressure measurements, and the ones most relevant to planetary modelling, have been obtained by shock compression. Of particular interest to the Jovian group are results for H 2 , H 2 O, CH 4 and NH 3 . Although the properties of metallic hydrogen have not been measured, they have been the subject of extensive calculations. In addition recent shock wave experiments on iron report to have detected melting under Earth core conditions. From this data theoretical models have been developed for computing the equations of state of materials used in planetary studies. A compelling feature that has followed from the use of improved material properties is a simplification in the planetary models. (author)

  4. Towards linearization of atmospheric radiative transfer in spherical geometry

    International Nuclear Information System (INIS)

    Walter, Holger H.; Landgraf, Jochen

    2005-01-01

    We present a general approach for the linearization of radiative transfer in a spherical planetary atmosphere. The approach is based on the forward-adjoint perturbation theory. In the first part we develop the theoretical background for a linearization of radiative transfer in spherical geometry. Using an operator formulation of radiative transfer allows one to derive the linearization principles in a universally valid notation. The application of the derived principles is demonstrated for a radiative transfer problem in simplified spherical geometry in the second part of this paper. Here, we calculate the derivatives of the radiance at the top of the atmosphere with respect to the absorption properties of a trace gas species in the case of a nadir-viewing satellite instrument

  5. Russian Planetary Exploration History, Development, Legacy, Prospects

    CERN Document Server

    Harvey, Brian

    2007-01-01

    Russia’s accomplishments in planetary space exploration were not achieved easily. Formerly, the USSR experienced frustration in trying to tame unreliable Molniya and Proton upper stages and in tracking spacecraft over long distances. This book will assess the scientific haul of data from the Venus and Mars missions and look at the engineering approaches. The USSR developed several generations of planetary probes: from MV and Zond to the Phobos type. The engineering techniques used and the science packages are examined, as well as the nature of the difficulties encountered which ruined several missions. The programme’s scientific and engineering legacy is also addressed, as well as its role within the Soviet space programme as a whole. Brian Harvey concludes by looking forward to future Russian planetary exploration (e.g Phobos Grunt sample return mission). Several plans have been considered and may, with a restoration of funding, come to fruition. Soviet studies of deep space and Mars missions (e.g. TMK, ...

  6. CHEMIFOGV - A Model to Simulate Radiation Fogs and their Interaction with Vegetation and Chemistry

    International Nuclear Information System (INIS)

    Winterrath, Tanja; Bott, Andreas

    2001-01-01

    Radiation fog is an important modifier of atmospheric compounds in the planetary boundary layer. In vegetated areas effects are especially pronounced due to the enlarged surface area. Besides affecting the lower boundary of atmospheric models fog acts as a multi-phase reaction chamber leading to acid deposition. Here we present the 1-dimensional radiation fog modelCHEMIFOG V to simulate regional radiation fog events. The key feature of the fog model is the detailed microphysics, where the aerosol/droplet spectrum is described with a joint 2-dimensional distribution, but also the dynamics, thermodynamics, and radiative transfer are calculated. To investigate the interaction between fog and the biosphere a multi-layer vegetation module, including a soil module as well as a dry deposition module were coupled. Vegetation influences the dynamics, thermodynamics, and the radiation field of the lowest atmospheric layers. With CHEMIFOG V , numerical case studies on dry and moist deposition processes on vegetation surfaces were performed. Hereby multi-phase chemistry and the processing of aerosols were considered. The results show that the chemical composition of the deposited fog droplets is mainly determined by the aerosol composition. Dry deposition fluxes are dependent on the incoming radiation and the leaves' surface conditions with respect to water coverage.Due to chemical aerosol processing and deposition, the aerosol spectrum is significantly modified in the planetary boundary layer

  7. Techniques for Engaging the Public in Planetary Science

    Science.gov (United States)

    Shupla, Christine; Shaner, Andrew; Smith Hackler, Amanda

    2017-10-01

    Public audiences are often curious about planetary science. Scientists and education and public engagement specialists can leverage this interest to build scientific literacy. This poster will highlight research-based techniques the authors have tested with a variety of audiences, and are disseminating to planetary scientists through trainings.Techniques include:Make it personal. Audiences are interested in personal stories, which can capture the excitement, joy, and challenges that planetary scientists experience in their research. Audiences can learn more about the nature of science by meeting planetary scientists and hearing personal stories about their motivations, interests, and how they conduct research.Share relevant connections. Most audiences have very limited understanding of the solar system and the features and compositions of planetary bodies, but they enjoy learning about those objects they can see at night and factors that connect to their culture or local community.Demonstrate concepts. Some concepts can be clarified with analogies, but others can be demonstrated or modeled with materials. Demonstrations that are messy, loud, or that yield surprising results are particularly good at capturing an audience’s attention, but if they don’t directly relate to the key concept, they can serve as a distraction.Give them a role. Audience participation is an important engagement technique. In a presentation, scientists can invite the audience to respond to questions, pause to share their thoughts with a neighbor, or vote on an answer. Audiences can respond physically to prompts, raising hands, pointing, or clapping, or even moving to different locations in the room.Enable the audience to conduct an activity. People learn best by doing and by teaching others; simple hands-on activities in which the audience is discovering something themselves can be extremely effective at engaging audiences.This poster will cite examples of each technique, resources that

  8. 3He Abundances in Planetary Nebulae

    Science.gov (United States)

    Guzman-Ramirez, Lizette

    2017-10-01

    Determination of the 3He isotope is important to many fields of astrophysics, including stellar evolution, chemical evolution, and cosmology. The isotope is produced in stars which evolve through the planetary nebula phase. Planetary nebulae are the final evolutionary phase of low- and intermediate-mass stars, where the extensive mass lost by the star on the asymptotic giant branch is ionised by the emerging white dwarf. This ejecta quickly disperses and merges with the surrounding ISM. 3He abundances in planetary nebulae have been derived from the hyperfine transition of the ionised 3He, 3He+, at the radio rest frequency 8.665 GHz. 3He abundances in PNe can help test models of the chemical evolution of the Galaxy. Many hours have been put into trying to detect this line, using telescopes like the Effelsberg 100m dish of the Max Planck Institute for Radio Astronomy, the National Radio Astronomy Observatory (NRAO) 140-foot telescope, the NRAO Very Large Array, the Arecibo antenna, the Green Bank Telescope, and only just recently, the Deep Space Station 63 antenna from the Madrid Deep Space Communications Complex.

  9. Variation of sodium on Mercury with solar radiation pressure

    International Nuclear Information System (INIS)

    Potter, A.E.; Morgan, T.H.

    1987-01-01

    It has been suggested that nonthermal Na atoms with velocities in excess of 2.1 km/sec in the Mercury atmosphere can be accelerated off the planet by solar radiation pressure; Na abundance may accordingly be expected to decrease with increasing radiation pressure. While this is confirmed by the present measurements, high resolution line profile measurements on Na emission indicate that very little, if any, of the Na is nonthermal, while the bulk is at a temperature approaching that of the planetary surface. Attention is given to explanations for the observed variation. 11 references

  10. Natural Frequencies and Vibrating Modes for a Magnetic Planetary Gear Drive

    Directory of Open Access Journals (Sweden)

    Lizhong Xu

    2012-01-01

    Full Text Available In this paper, a dynamic model for a magnetic planetary gear drive is proposed. Based on the model, the dynamic equations for the magnetic planetary gear drive are given. From the magnetic meshing forces and torques between the elements for the drive system, the tangent and radial magnetic meshing stiffness is obtained. Using these equations, the natural frequencies and the modes of the magnetic planetary gear drive are investigated. The sensitivity of the natural frequencies to the system parameters is discussed. Results show that the pole pair number and the air gap have obvious effects on the natural frequencies. For the planetary gear number larger than two, the vibrations of the drive system include the torsion mode of the center elements, the translation mode of the center elements, and the planet modes. For the planetary gear number equal to two, the planet mode does not occur, the crown mode and the sun gear mode occur.

  11. The Lunar and Planetary Institute Summer Intern Program in Planetary Science

    Science.gov (United States)

    Kramer, G. Y.

    2017-12-01

    Since 1977, the Lunar and Planetary Institute (LPI) Summer Intern Program brings undergraduate students from across the world to Houston for 10 weeks of their summer where they work one-on-one with a scientist at either LPI or Johnson Space Center on a cutting-edge research project in the planetary sciences. The program is geared for students finishing their sophomore and junior years, although graduating seniors may also apply. It is open to international undergraduates as well as students from the United States. Applicants must have at least 50 semester hours of credit (or equivalent sophomore status) and an interest in pursuing a career in the sciences. The application process is somewhat rigorous, requiring three letters of recommendation, official college transcripts, and a letter describing their background, interests, and career goals. The deadline for applications is in early January of that year of the internship. More information about the program and how to apply can be found on the LPI website: http://www.lpi.usra.edu/lpiintern/. Each advisor reads through the applications, looking for academically excellent students and those with scientific interest and backgrounds compatible with the advisor's specific project. Interns are selected fairly from the applicant pool - there are no pre-arranged agreements or selections based on who knows whom. The projects are different every year as new advisors come into the program, and existing ones change their research interest and directions. The LPI Summer Intern Program gives students the opportunity to participate in peer-reviewed research, learn from top-notch planetary scientists, and preview various careers in science. For many interns, this program was a defining moment in their careers - when they decided whether or not to follow an academic path, which direction they would take, and how. While past interns can be found all over the world and in a wide variety of occupations, all share the common bond of

  12. The role of clouds in the surface energy balance over the Amazon forest

    International Nuclear Information System (INIS)

    Eltahir, E.A.B.; Humphries, E.J. Jr.

    1998-01-01

    Deforestation in the Amazon region will initially impact the energy balance at the land surface through changes in land cover and surface hydrology. However, continuation of this human activity will eventually lead to atmospheric feedbacks, including changes in cloudiness which may play an important role in the final equilibrium of solar and terrestrial radiation at the surface. In this study, the different components of surface radiation over an undisturbed forest in the Amazon region are computed using data from the Amazon region micrometerological experiment (ARME). Several measures of cloudiness are defined: two estimated from the terrestrial radiation measurements, and one from the solar radiation measurements. The sensitivity of the surface fluxes of solar and terrestrial radiation to natural variability in cloudiness is investigated to infer the potential role of the cloudiness feedback in the surface energy balance. The results of this analysis indicate that a 1% decrease in cloudiness would increase net solar radiation by ca. 1.6 W/m 2 . However, the overall magnitude of this feedback, due to total deforestation of the Amazon forest, is likely to be of the same order as the magnitude of the decrease in net solar radiation due to the observed increase in surface albedo following deforestation. Hence, the total change in net solar radiation is likely to have a negligible magnitude. In contrast to this conclusion, we find that terrestrial radiation is likely to be more strongly affected; reduced cloudiness will decrease net terrestrial radiation; a 1% decrease in cloudiness induces a reduction in net terrestrial radiation of ca. 0.7 W/m 2 ; this process augments the similar effects of the predicted warming and drying in the boundary layer. Due to the cloudiness feedback, the most significant effect of large-scale deforestation on the surface energy balance is likely to be in the modification of the terrestrial radiation field rather than the classical albedo

  13. Novel Space Exploration Technique for Analysing Planetary Atmospheres

    OpenAIRE

    Dekoulis, George

    2010-01-01

    The chapter presents a new reconfigurable wide-beam radio interferometer system for analysing planetary atmospheres. The system operates at frequencies, where the ionisation of the planetary plasma regions induces strong attenuation. For Earth, the attenuation is undistinguishable from the CMB at frequencies over 50 MHz. The system introduces a set of advanced specifications to this field of science, previously unseen in similar suborbital experiments. The reprogrammable dynamic range of the ...

  14. Soft x-ray Planetary Imager

    Data.gov (United States)

    National Aeronautics and Space Administration — The project is to prototype a soft X-ray Imager for planetary applications that has the sensitivity to observe solar system sources of soft  X-ray emission. A strong...

  15. Extreme Ionizing-Radiation-Resistant Bacterium

    Science.gov (United States)

    Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

    2013-01-01

    There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing micro-organisms. Eradi cation techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation-based sterilization processes. Due to their resistance to a variety of perturbations, the nonspore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-sporeforming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/m2), and desiccation (years). These resistive phenotypes of Deinococcus enhance the

  16. Balancing radiation benefits and risks: The needs of an informed public

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-01

    The American public`s perceptions regarding ionizing radiation do not always conform to or correlate with scientific evidence. The ultimate purpose of this coordinated Federal effort and report is to increase the public`s knowledge of the benefits and risks associated with ionizing radiation. This report is divided into five sections. The first section, Introduction, discusses the public`s knowledge of radiation, their perceptions of benefits versus risks, and the Federal government`s role in public education. The section also outlines the charge to the Subpanel. Radiation Issues and Public Reactions discusses several radiation issues important to Federal agencies for which public education programs need to be established or enhanced. Federal Programs describes Federal agencies with public education programs on radiation and the nature of the programs they support. Education Issues and Federal Strategies explores the elements identified by the Subpanel as critical to the development and implementation of an effective Federal program in the area of public education on radiation issues and nuclear technologies. An important issue repeatedly brought up during the public sector presentations to the Subpanel was the perceived lack of Federal credibility on radiation issues in the eyes of the public. To some degree, this concern was factored into all of the recommendations developed by the subpanel. The issues discussed in this section include the fragmented nature of Federal radiation programs and the need to improve credibility, promote agency responsiveness, and support the enhancement of scientific literacy. Finally, under Recommendations, the Subpanel discusses its overall findings and conclusions.

  17. Balancing radiation benefits and risks: The needs of an informed public

    International Nuclear Information System (INIS)

    1994-04-01

    The American public's perceptions regarding ionizing radiation do not always conform to or correlate with scientific evidence. The ultimate purpose of this coordinated Federal effort and report is to increase the public's knowledge of the benefits and risks associated with ionizing radiation. This report is divided into five sections. The first section, Introduction, discusses the public's knowledge of radiation, their perceptions of benefits versus risks, and the Federal government's role in public education. The section also outlines the charge to the Subpanel. Radiation Issues and Public Reactions discusses several radiation issues important to Federal agencies for which public education programs need to be established or enhanced. Federal Programs describes Federal agencies with public education programs on radiation and the nature of the programs they support. Education Issues and Federal Strategies explores the elements identified by the Subpanel as critical to the development and implementation of an effective Federal program in the area of public education on radiation issues and nuclear technologies. An important issue repeatedly brought up during the public sector presentations to the Subpanel was the perceived lack of Federal credibility on radiation issues in the eyes of the public. To some degree, this concern was factored into all of the recommendations developed by the subpanel. The issues discussed in this section include the fragmented nature of Federal radiation programs and the need to improve credibility, promote agency responsiveness, and support the enhancement of scientific literacy. Finally, under Recommendations, the Subpanel discusses its overall findings and conclusions

  18. Polarimetry of stars and planetary systems

    National Research Council Canada - National Science Library

    Kolokolova, Ludmilla; Hough, James; Levasseur-Regourd, Anny-Chantal

    2015-01-01

    ... fields of polarimetric exploration, including proto-planetary and debris discs, icy satellites, transneptunian objects, exoplanets and the search for extraterrestrial life -- unique results produced...

  19. Intelligence for Human-Assistant Planetary Surface Robots

    Science.gov (United States)

    Hirsh, Robert; Graham, Jeffrey; Tyree, Kimberly; Sierhuis, Maarten; Clancey, William J.

    2006-01-01

    The central premise in developing effective human-assistant planetary surface robots is that robotic intelligence is needed. The exact type, method, forms and/or quantity of intelligence is an open issue being explored on the ERA project, as well as others. In addition to field testing, theoretical research into this area can help provide answers on how to design future planetary robots. Many fundamental intelligence issues are discussed by Murphy [2], including (a) learning, (b) planning, (c) reasoning, (d) problem solving, (e) knowledge representation, and (f) computer vision (stereo tracking, gestures). The new "social interaction/emotional" form of intelligence that some consider critical to Human Robot Interaction (HRI) can also be addressed by human assistant planetary surface robots, as human operators feel more comfortable working with a robot when the robot is verbally (or even physically) interacting with them. Arkin [3] and Murphy are both proponents of the hybrid deliberative-reasoning/reactive-execution architecture as the best general architecture for fully realizing robot potential, and the robots discussed herein implement a design continuously progressing toward this hybrid philosophy. The remainder of this chapter will describe the challenges associated with robotic assistance to astronauts, our general research approach, the intelligence incorporated into our robots, and the results and lessons learned from over six years of testing human-assistant mobile robots in field settings relevant to planetary exploration. The chapter concludes with some key considerations for future work in this area.

  20. A radio search for planetary nebulae near the galactic center

    International Nuclear Information System (INIS)

    Isaacman, R.B.

    1980-01-01

    Because of galactic center is a hostile environment, and because planetaries are weak radio emitters, it is not clear a priori that one expects to detect any planetary nebulae at all in the nuclear region of the Galaxy. Therefore the expected lifetime and flux density distribution of galactic center nebulae is considered. The principal observational results from the Westerbork data, and the results of some pilot observations with the Very Large Array, which were intended to distinguish planetaries from other radio sources on an individual basis are given. (Auth.)

  1. Residual signal feature extraction for gearbox planetary stage fault detection

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Ursin, Thomas; Sweeney, Christian Walsted

    2017-01-01

    Faults in planetary gears and related bearings, e.g. planet bearings and planet carrier bearings, pose inherent difficulties on their accurate and consistent detection associated mainly to the low energy in slow rotating stages and the operating complexity of planetary gearboxes. In this work......, identification of the expected spectral signature for proper residual signal calculation and filtering of any frequency component not related to the planetary stage. Two field cases of planet carrier bearing defect and planet wheel spalling are presented and discussed, showing the efficiency of the followed...

  2. The Energetic Demands and Planetary Footprint of Alternative Human Diets

    Science.gov (United States)

    Eshel, G.; Martin, P. A.

    2005-12-01

    Agriculture is one of the major vehicles of human alteration of the planetary environment. Yet different diets vary vastly in terms of both their energetic demands and overall planetary footprint. We present a quantitative argument that demonstrates that plant-based diets exert vastly smaller planetary environmental cost than animal-based ones. We demonstrate that under a reasonable and readily defensible set of assumptions, a plant-based diet differs from the average American diet by as much energy as the difference between driving a compact and efficient sedan and a Sport Utility Vehicle.

  3. The Strength Analysis of Differential Planetary Gears of Gearbox for Concrete Mixer Truck

    Science.gov (United States)

    Bae, M. H.; Bae, T. Y.; Kim, D. J.

    2018-03-01

    The power train of mixer gearbox for concrete mixer truck includes differential planetary gears to get large reduction ratio for operating mixer a drum and simple structure. The planetary gears are very important part of a mixer gearbox where strength problems namely gear bending stress, gear compressive stress and scoring failure are the main concern. In the present study, calculating specifications of the differential planetary gears and analyzing the gear bending and compressive stresses as well as scoring factor of the differential planetary gears gearbox for an optimal design of the mixer gearbox in respect to cost and reliability are investigated. The analyses of actual gear bending and compressive stresses of the differential planetary gears using Lewes & Hertz equation and verifications of the calculated specifications of the differential planetary gears evaluate the results with the data of allowable bending and compressive stress from the Stress-No. of cycles curves of gears. In addition, we also analyze actual gear scoring factor as well as evaluate the possibility of scoring failure of the differential planetary gear.

  4. A Synergistic Approach to Interpreting Planetary Atmospheres

    Science.gov (United States)

    Batalha, Natasha E.

    We will soon have the technological capability to measure the atmospheric composition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In contrast to jovian-like atmospheres, whose bulk compositions consist of hydrogen and helium, terrestrial planet atmospheres are likely comprised of high mean molecular weight secondary atmospheres, which have gone through a high degree of evolution. For example, present-day Mars has a frozen surface with a thin tenuous atmosphere, but 4 billion years ago it may have been warmed by a thick greenhouse atmosphere. Several processes contribute to a planet's atmospheric evolution: stellar evolution, geological processes, atmospheric escape, biology, etc. Each of these individual processes affects the planetary system as a whole and therefore they all must be considered in the modeling of terrestrial planets. In order to demonstrate the intricacies in modeling terrestrial planets, I use early Mars as a case study. I leverage a combination of one-dimensional climate, photochemical and energy balance models in order to create one self-consistent model that closely matches currently available climate data. One-dimensional models can address several processes: the influence of greenhouse gases on heating, the effect of the planet's geological processes (i.e. volcanoes and the carbonatesilicate cycle) on the atmosphere, the effect of rainfall on atmospheric composition and the stellar irradiance. After demonstrating the number of assumptions required to build a model, I look towards what exactly we can learn from remote observations of temperate Earths and Super Earths. However, unlike in-situ observations from our own solar system, remote sensing techniques need to be developed and understood in order to accurately characterize exo-atmospheres. I describe the models used to create synthetic transit transmission observations, which includes models of

  5. The complex planetary synchronization structure of the solar system

    Science.gov (United States)

    Scafetta, N.

    2014-01-01

    The complex planetary synchronization structure of the solar system, which since Pythagoras of Samos (ca. 570-495 BC) is known as the music of the spheres, is briefly reviewed from the Renaissance up to contemporary research. Copernicus' heliocentric model from 1543 suggested that the planets of our solar system form a kind of mutually ordered and quasi-synchronized system. From 1596 to 1619 Kepler formulated preliminary mathematical relations of approximate commensurabilities among the planets, which were later reformulated in the Titius-Bode rule (1766-1772), which successfully predicted the orbital position of Ceres and Uranus. Following the discovery of the ~ 11 yr sunspot cycle, in 1859 Wolf suggested that the observed solar variability could be approximately synchronized with the orbital movements of Venus, Earth, Jupiter and Saturn. Modern research has further confirmed that (1) the planetary orbital periods can be approximately deduced from a simple system of resonant frequencies; (2) the solar system oscillates with a specific set of gravitational frequencies, and many of them (e.g., within the range between 3 yr and 100 yr) can be approximately constructed as harmonics of a base period of ~ 178.38 yr; and (3) solar and climate records are also characterized by planetary harmonics from the monthly to the millennial timescales. This short review concludes with an emphasis on the contribution of the author's research on the empirical evidences and physical modeling of both solar and climate variability based on astronomical harmonics. The general conclusion is that the solar system works as a resonator characterized by a specific harmonic planetary structure that also synchronizes the Sun's activity and the Earth's climate. The special issue Pattern in solar variability, their planetary origin and terrestrial impacts (Mörner et al., 2013) further develops the ideas about the planetary-solar-terrestrial interaction with the personal contribution of 10

  6. Vibration behavior optimization of planetary gear sets

    Directory of Open Access Journals (Sweden)

    Farshad Shakeri Aski

    2014-12-01

    Full Text Available This paper presents a global optimization method focused on planetary gear vibration reduction by means of tip relief profile modifications. A nonlinear dynamic model is used to study the vibration behavior. In order to investigate the optimal radius and amplitude, Brute Force method optimization is used. One approach in optimization is straightforward and requires considerable computation power: brute force methods try to calculate all possible solutions and decide afterwards which one is the best. Results show the influence of optimal profile on planetary gear vibrations.

  7. Planetary nebulae and the interstellar magnetic field

    International Nuclear Information System (INIS)

    Heiligman, G.M.

    1980-01-01

    Previous workers have found a statistical correlation between the projected directions of the interstellar magnetic field and the major axes of planetary nebulae. This result has been examined theoretically using a numerical hydromagnetic model of a cold plasma nebula expanding into a uniform vacuum magnetic field, with nebular gas accreting on the surface. It is found that magnetic pressure alone is probably not sufficient to shape most planetary nebulae to the observed degree. Phenomena are discussed which could amplify simple magnetic pressure, alter nebular morphology and account for the observed correlation. (author)

  8. Absolute Navigation Information Estimation for Micro Planetary Rovers

    Directory of Open Access Journals (Sweden)

    Muhammad Ilyas

    2016-03-01

    Full Text Available This paper provides algorithms to estimate absolute navigation information, e.g., absolute attitude and position, by using low power, weight and volume Microelectromechanical Systems-type (MEMS sensors that are suitable for micro planetary rovers. Planetary rovers appear to be easily navigable robots due to their extreme slow speed and rotation but, unfortunately, the sensor suites available for terrestrial robots are not always available for planetary rover navigation. This makes them difficult to navigate in a completely unexplored, harsh and complex environment. Whereas the relative attitude and position can be tracked in a similar way as for ground robots, absolute navigation information, unlike in terrestrial applications, is difficult to obtain for a remote celestial body, such as Mars or the Moon. In this paper, an algorithm called the EASI algorithm (Estimation of Attitude using Sun sensor and Inclinometer is presented to estimate the absolute attitude using a MEMS-type sun sensor and inclinometer, only. Moreover, the output of the EASI algorithm is fused with MEMS gyros to produce more accurate and reliable attitude estimates. An absolute position estimation algorithm has also been presented based on these on-board sensors. Experimental results demonstrate the viability of the proposed algorithms and the sensor suite for low-cost and low-weight micro planetary rovers.

  9. Trapping in stochastic mechanics and applications to covers of clouds and radiation belts

    International Nuclear Information System (INIS)

    Albeverio, S.; Blanchard, P.; Combe, P.; Rodriguez, R.; Sirugue, M.; Sirugue-Collin, M.

    1984-11-01

    It is possible to assign a stochastic acceleration to conservative stochastic diffusion processes. As a basic assumption, this stochastic acceleration is set equal to the deterministic smooth component of the external force acting on the particle, whereas the influences of the remainder is modelled by a diffusion coefficient. In this paper, we shall try to see whether it can account for the observation in two cases: the cover of clouds of planets and the radiation belts in the planetary magnetic field. We describe the basic properties of Newtonian Diffusion Stochastic Processes and indicate their connection with Schroedinger-like equations. Furthermore we give a heuristic interpretation of the nodal surfaces as impenetrable barriers for Newtonian Stochastic Diffusion Processes. The possible applications to the observed average cloud covering in the planetary atmosphere are presented we discuss the radiation belts (Van Allen Belts) along the previous ideas

  10. Workshop on Advanced Technologies for Planetary Instruments, part 1

    International Nuclear Information System (INIS)

    Appleby, J.F.

    1993-01-01

    This meeting was conceived in response to new challenges facing NASA's robotic solar system exploration program. This volume contains papers presented at the Workshop on Advanced Technologies for Planetary Instruments on 28-30 Apr. 1993. This meeting was conceived in response to new challenges facing NASA's robotic solar system exploration program. Over the past several years, SDIO has sponsored a significant technology development program aimed, in part, at the production of instruments with these characteristics. This workshop provided an opportunity for specialists from the planetary science and DOD communities to establish contacts, to explore common technical ground in an open forum, and more specifically, to discuss the applicability of SDIO's technology base to planetary science instruments

  11. An ultrasound mini-balance for measurement of therapy level ultrasound

    International Nuclear Information System (INIS)

    Sutton, Yvonne; McBride, Karne; Pye, Stephen

    2006-01-01

    This paper describes a cost-effective method for measuring acoustic power using a radiation force balance. The device is based around a long established balance design with a gantry arrangement fitted with an absorbing target. The notion of this balance design is that it can easily be constructed from materials that would be readily available within a clinical or industrial environment. The mini-balance was calibrated using a transfer standard against an NPL Reference balance, so a comparison of the performance between the two systems could be assessed. The measurements were completed at 1 MHz and 3 MHz and over the acoustic power range of 1 W to 15 W. The results show the acoustic power measured on the mini-balance to be within 5% of the reference measurements made on the NPL Balance. A separate systematic uncertainty budget is also presented based on studies made on the balance and on similar systems. The overall expanded uncertainty was calculated to be within 14% at 1 W level, decreasing with increasing power level to 7.4% above 5 W

  12. High-resolution 8-13 micron imaging of the planetary nebulae BD + 30 deg 3639 and NGC 6572

    International Nuclear Information System (INIS)

    Hora, J.L.; Hoffmann, W.F.; Deutsch, L.K.; Fazio, G.G.

    1990-01-01

    High-resolution midinfrared images of the planetary nebulae BD + 30 deg 3639 and NGC 6572 are presented at 8.3, 8.7, 9.8, 11.2, and 12.4 microns. Analysis of the maps of BD + 30 deg 3639 supports a model in which the infrared emission originates from two spatially distinct components, one which is responsible for the continuum radiation at 8-12 microns and the other which produces the emission-line features. The NGC 6572 images provides evidence for a previously undetected 11.2 micron UIR emission feature. Comparison with radio continuum maps indicates that the distribution of dust is similar to the distribution of ionized gas in each nebula. Various models of source morphology are also investigated. The planetary nebulae DB + 30 deg 3639 and NGC 6572 can be modeled by an optically thin cylinder or a prolate ellipsoid with enhanced equatorial emission. These models reproduce well the general features of the nebula, such as the bipolar lobes of emission and the ring structure. 67 refs

  13. Planetary boundaries: exploring the safe operating space for humanity

    Science.gov (United States)

    Johan Rockström; Will Steffen; Kevin Noone; Asa Persson; F. Stuart Chapin; Eric Lambin; Timothy M. Lenton; Marten Scheffer; Carl Folke; Hans Joachim Schellnhuber; Björn Nykvist; Cynthia A. de Wit; Terry Hughes; Sander van der Leeuw; Henning Rodhe; Sverker Sörlin; Peter K. Snyder; Robert Costanza; Uno Svedin; Malin Falkenmark; Louise Karlberg; Robert W. Corell; Victoria J. Fabry; James Hansen; Brian Walker; Diana Liverman; Katherine Richardson; Paul Crutzen; Jonathan Foley

    2009-01-01

    Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due...

  14. Probing clouds in planets with a simple radiative transfer model: the Jupiter case

    International Nuclear Information System (INIS)

    Mendikoa, Iñigo; Pérez-Hoyos, Santiago; Sánchez-Lavega, Agustín

    2012-01-01

    Remote sensing of planets evokes using expensive on-orbit satellites and gathering complex data from space. However, the basic properties of clouds in planetary atmospheres can be successfully estimated with small telescopes even from an urban environment using currently available and affordable technology. This makes the process accessible for undergraduate students while preserving most of the physics and mathematics involved. This paper presents the methodology for carrying out a photometric study of planetary atmospheres, focused on the planet Jupiter. The method introduces the basics of radiative transfer in planetary atmospheres, some notions on inverse problem theory and the fundamentals of planetary photometry. As will be shown, the procedure allows the student to derive the spectral reflectivity and top altitude of clouds from observations at different wavelengths by applying a simple but enlightening ‘reflective layer model’. In this way, the planet's atmospheric structure is estimated by students as an inverse problem from the observed photometry. Web resources are also provided to help those unable to obtain telescopic observations of the planets. (paper)

  15. Probing clouds in planets with a simple radiative transfer model: the Jupiter case

    Science.gov (United States)

    Mendikoa, Iñigo; Pérez-Hoyos, Santiago; Sánchez-Lavega, Agustín

    2012-11-01

    Remote sensing of planets evokes using expensive on-orbit satellites and gathering complex data from space. However, the basic properties of clouds in planetary atmospheres can be successfully estimated with small telescopes even from an urban environment using currently available and affordable technology. This makes the process accessible for undergraduate students while preserving most of the physics and mathematics involved. This paper presents the methodology for carrying out a photometric study of planetary atmospheres, focused on the planet Jupiter. The method introduces the basics of radiative transfer in planetary atmospheres, some notions on inverse problem theory and the fundamentals of planetary photometry. As will be shown, the procedure allows the student to derive the spectral reflectivity and top altitude of clouds from observations at different wavelengths by applying a simple but enlightening ‘reflective layer model’. In this way, the planet's atmospheric structure is estimated by students as an inverse problem from the observed photometry. Web resources are also provided to help those unable to obtain telescopic observations of the planets.

  16. Laser Mass Spectrometry in Planetary Science

    International Nuclear Information System (INIS)

    Wurz, P.; Whitby, J. A.; Managadze, G. G.

    2009-01-01

    Knowing the chemical, elemental, and isotopic composition of planetary objects allows the study of their origin and evolution within the context of our solar system. Exploration plans in planetary research of several space agencies consider landing spacecraft for future missions. Although there have been successful landers in the past, more landers are foreseen for Mars and its moons, Venus, the jovian moons, and asteroids. Furthermore, a mass spectrometer on a landed spacecraft can assist in the sample selection in a sample-return mission and provide mineralogical context, or identify possible toxic soils on Mars for manned Mars exploration. Given the resources available on landed spacecraft mass spectrometers, as well as any other instrument, have to be highly miniaturised.

  17. Energy balance in the solar transition region. I - Hydrostatic thermal models with ambipolar diffusion

    Science.gov (United States)

    Fontenla, J. M.; Avrett, E. H.; Loeser, R.

    1990-01-01

    The energy balance in the lower transition region is analyzed by constructing theoretical models which satisfy the energy balance constraint. The energy balance is achieved by balancing the radiative losses and the energy flowing downward from the corona. This energy flow is mainly in two forms: conductive heat flow and hydrogen ionization energy flow due to ambipolar diffusion. Hydrostatic equilibrium is assumed, and, in a first calculation, local mechanical heating and Joule heating are ignored. In a second model, some mechanical heating compatible with chromospheric energy-balance calculations is introduced. The models are computed for a partial non-LTE approach in which radiation departs strongly from LTE but particles depart from Maxwellian distributions only to first order. The results, which apply to cases where the magnetic field is either absent, or uniform and vertical, are compared with the observed Lyman lines and continuum from the average quiet sun. The approximate agreement suggests that this type of model can roughly explain the observed intensities in a physically meaningful way, assuming only a few free parameters specified as chromospheric boundary conditions.

  18. Europlanet/IDIS: Combining Diverse Planetary Observations and Models

    Science.gov (United States)

    Schmidt, Walter; Capria, Maria Teresa; Chanteur, Gerard

    2013-04-01

    Planetary research involves a diversity of research fields from astrophysics and plasma physics to atmospheric physics, climatology, spectroscopy and surface imaging. Data from all these disciplines are collected from various space-borne platforms or telescopes, supported by modelling teams and laboratory work. In order to interpret one set of data often supporting data from different disciplines and other missions are needed while the scientist does not always have the detailed expertise to access and utilize these observations. The Integrated and Distributed Information System (IDIS) [1], developed in the framework of the Europlanet-RI project, implements a Virtual Observatory approach ([2] and [3]), where different data sets, stored in archives around the world and in different formats, are accessed, re-formatted and combined to meet the user's requirements without the need of familiarizing oneself with the different technical details. While observational astrophysical data from different observatories could already earlier be accessed via Virtual Observatories, this concept is now extended to diverse planetary data and related model data sets, spectral data bases etc. A dedicated XML-based Europlanet Data Model (EPN-DM) [4] was developed based on data models from the planetary science community and the Virtual Observatory approach. A dedicated editor simplifies the registration of new resources. As the EPN-DM is a super-set of existing data models existing archives as well as new spectroscopic or chemical data bases for the interpretation of atmospheric or surface observations, or even modeling facilities at research institutes in Europe or Russia can be easily integrated and accessed via a Table Access Protocol (EPN-TAP) [5] adapted from the corresponding protocol of the International Virtual Observatory Alliance [6] (IVOA-TAP). EPN-TAP allows to search catalogues, retrieve data and make them available through standard IVOA tools if the access to the archive

  19. Teaching Planetary Science as Part of the Search for Extraterrestrial Intelligence (SETI)

    Science.gov (United States)

    Margot, Jean-Luc; Greenberg, Adam H.

    2017-10-01

    In Spring 2016 and 2017, UCLA offered a course titled "EPSS C179/279 - Search for Extraterrestrial Intelligence: Theory and Applications". The course is designed for advanced undergraduate students and graduate students in the science, technical, engineering, and mathematical fields. Each year, students designed an observing sequence for the Green Bank telescope, observed known planetary systems remotely, wrote a sophisticated and modular data processing pipeline, analyzed the data, and presented their results. In 2016, 15 students participated in the course (9U, 5G; 11M, 3F) and observed 14 planetary systems in the Kepler field. In 2017, 17 students participated (15U, 2G; 10M, 7F) and observed 10 planetary systems in the Kepler field, TRAPPIST-1, and LHS 1140. In order to select suitable targets, students learned about planetary systems, planetary habitability, and planetary dynamics. In addition to planetary science fundamentals, students learned radio astronomy fundamentals, collaborative software development, signal processing techniques, and statistics. Evaluations indicate that the course is challenging but that students are eager to learn because of the engrossing nature of SETI. Students particularly value the teamwork approach, the observing experience, and working with their own data. The next offering of the course will be in Spring 2018. Additional information about our SETI work is available at seti.ucla.edu.

  20. Earth as a radio source: terrestrial kilometric radiation. Progress report

    International Nuclear Information System (INIS)

    Gurnett, D.A.

    1974-02-01

    Radio wave experiments on the IMP-6 and 8 satellites have shown that the earth emits very intense electromagnetic radiation in the frequency range from about 50 kHz to 500 kHz. A peak intensity the total power emitted in this frequency range is about 1 billion watts. The earth is, therefore, a very intense planetary radio source, with a total power output comparable to the decametric radio emission from Jupiter. This radio emission from the earth is referred to as terrestrial kilometric radiation. Terrestrial kilometric radiation appears to originate from low altitudes (less than 3.0 Re) in the auroral region. Possible mechanisms which can explain the generation and propagation of the terrestrial kilometric radiation are discussed. (U.S.)

  1. Structure of planetary nebulae

    International Nuclear Information System (INIS)

    Goad, L.E.

    1975-01-01

    Image-tube photographs of planetary nebulae taken through narrow-band interference filters are used to map the surface brightness of these nebulae in their most prominent emission lines. These observations are best understood in terms of a two-component model consisting of a tenuous diffuse nebular medium and a network of dense knots and filaments with neutral cores. The observations of the diffuse component indicate that the inner regions of these nebulae are hollow shells. This suggests that steady stellar winds are the dominant factor in determining the structure of the central regions of planetary nebulae. The observations of the filamentary components of NGC 40 and NGC 6720 show that the observed nebular features can result from the illumination of the inner edges of dense fragmentary neutral filaments by the central stars of these nebulae. From the analysis of the observations of the low-excitation lines in NGC 2392, it is concluded that the rate constant for the N + --H charge transfer reaction is less than 10 -12 cm 3 sec -1

  2. Parallel Study of HEND, RAD, and DAN Instrument Response to Martian Radiation and Surface Conditions

    Science.gov (United States)

    Martiniez Sierra, Luz Maria; Jun, Insoo; Litvak, Maxim; Sanin, Anton; Mitrofanov, Igor; Zeitlin, Cary

    2015-01-01

    Nuclear detection methods are being used to understand the radiation environment at Mars. JPL (Jet Propulsion Laboratory) assets on Mars include: Orbiter -2001 Mars Odyssey [High Energy Neutron Detector (HEND)]; Mars Science Laboratory Rover -Curiosity [(Radiation Assessment Detector (RAD); Dynamic Albedo Neutron (DAN))]. Spacecraft have instruments able to detect ionizing and non-ionizing radiation. Instrument response on orbit and on the surface of Mars to space weather and local conditions [is discussed] - Data available at NASA-PDS (Planetary Data System).

  3. OH+ emission from cometary knots in planetary nebulae

    Science.gov (United States)

    Priestley, F. D.; Barlow, M. J.

    2018-05-01

    We model the molecular emission from cometary knots in planetary nebulae (PNe) using a combination of photoionization and photodissociation region (PDR) codes, for a range of central star properties and gas densities. Without the inclusion of ionizing extreme ultraviolet (EUV) radiation, our models require central star temperatures T* to be near the upper limit of the range investigated in order to match observed H2 and OH+ surface brightnesses consistent with observations - with the addition of EUV flux, our models reproduce observed OH+ surface brightnesses for T* ≥ 100 kK. For T* non-detection of this molecule in PNe with such central star temperatures. Our predicted level of H2 emission is somewhat weaker than commonly observed in PNe, which may be resolved by the inclusion of shock heating or fluorescence due to UV photons. Some of our models also predict ArH+ and HeH+ rotational line emission above detection thresholds, despite neither molecule having been detected in PNe, although the inclusion of photodissociation by EUV photons, which is neglected by our models, would be expected to reduce their detectability.

  4. The Planetary Nebula Spectrograph : The green light for galaxy kinematics

    NARCIS (Netherlands)

    Douglas, NG; Arnaboldi, M; Freeman, KC; Kuijken, K; Merrifield, MR; Romanowsky, AJ; Taylor, K; Capaccioli, M; Axelrod, T; Gilmozzi, R; Hart, J; Bloxham, G; Jones, D

    2002-01-01

    Planetary nebulae (PNe) are now well established as probes of galaxy dynamics and as standard candles in distance determinations. Motivated by the need to improve the efficiency of planetary nebulae searches and the speed with which their radial velocities are determined, a dedicated instrument-the

  5. China's roadmap for planetary exploration

    Science.gov (United States)

    Wei, Yong; Yao, Zhonghua; Wan, Weixing

    2018-05-01

    China has approved or planned a string of several space exploration missions to be launched over the next decade. A new generation of planetary scientists in China is playing an important role in determining the scientific goals of future missions.

  6. Using Sandia's Z Machine and Density Functional Theory Simulations to Understand Planetary Materials

    Science.gov (United States)

    Root, Seth

    2017-06-01

    The use of Z, NIF, and Omega have produced many breakthrough results in high pressure physics. One area that has greatly benefited from these facilities is the planetary sciences. The high pressure behavior of planetary materials has implications for numerous geophysical and planetary processes. The continuing discovery of exosolar super-Earths demonstrates the need for accurate equation of state data to better inform our models of their interior structures. Planetary collision processes, such as the moon-forming giant impact, require understanding planetary materials over a wide-range of pressures and temperatures. Using Z, we examined the shock compression response of some common planetary materials: MgO, Mg2SiO4, and Fe2O3 (hematite). We compare the experimental shock compression measurements with density functional theory (DFT) based quantum molecular dynamics (QMD) simulations. The combination of experiment and theory provides clearer understanding of planetary materials properties at extreme conditions. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. A drilling tool design and in situ identification of planetary regolith mechanical parameters

    Science.gov (United States)

    Zhang, Weiwei; Jiang, Shengyuan; Ji, Jie; Tang, Dewei

    2018-05-01

    The physical and mechanical properties as well as the heat flux of regolith are critical evidence in the study of planetary origin and evolution. Moreover, the mechanical properties of planetary regolith have great value for guiding future human planetary activities. For planetary subsurface exploration, an inchworm boring robot (IBR) has been proposed to penetrate the regolith, and the mechanical properties of the regolith are expected to be simultaneously investigated during the penetration process using the drilling tool on the IBR. This paper provides a preliminary study of an in situ method for measuring planetary regolith mechanical parameters using a drilling tool on a test bed. A conical-screw drilling tool was designed, and its drilling load characteristics were experimentally analyzed. Based on the drilling tool-regolith interaction model, two identification methods for determining the planetary regolith bearing and shearing parameters are proposed. The bearing and shearing parameters of lunar regolith simulant were successfully determined according to the pressure-sinkage tests and shear tests conducted on the test bed. The effects of the operating parameters on the identification results were also analyzed. The results indicate a feasible scheme for future planetary subsurface exploration.

  8. Planetary protection implementation on future Mars lander missions

    Science.gov (United States)

    Howell, Robert; Devincenzi, Donald L.

    1993-01-01

    A workshop was convened to discuss the subject of planetary protection implementation for Mars lander missions. It was sponsored and organized by the Exobiology Implementation Team of the U.S./Russian Joint Working Group on Space Biomedical and Life Support Systems. The objective of the workshop was to discuss planetary protection issues for the Russian Mars '94 mission, which is currently under development, as well as for additional future Mars lander missions including the planned Mars '96 and U.S. MESUR Pathfinder and Network missions. A series of invited presentations was made to ensure that workshop participants had access to information relevant to the planned discussions. The topics summarized in this report include exobiology science objectives for Mars exploration, current international policy on planetary protection, planetary protection requirements developed for earlier missions, mission plans and designs for future U.S. and Russian Mars landers, biological contamination of spacecraft components, and techniques for spacecraft bioload reduction. In addition, the recent recommendations of the U.S. Space Studies Board (SSB) on this subject were also summarized. Much of the discussion focused on the recommendations of the SSB. The SSB proposed relaxing the planetary protection requirements for those Mars lander missions that do not contain life detection experiments, but maintaining Viking-like requirements for those missions that do contain life detection experiments. The SSB recommendations were found to be acceptable as a guide for future missions, although many questions and concerns about interpretation were raised and are summarized. Significant among the concerns was the need for more quantitative guidelines to prevent misinterpretation by project offices and better access to and use of the Viking data base of bioassays to specify microbial burden targets. Among the questions raised were how will the SSB recommendations be integrated with existing

  9. Planetary protection implementation on future Mars lander missions

    Science.gov (United States)

    Howell, Robert; Devincenzi, Donald L.

    1993-06-01

    A workshop was convened to discuss the subject of planetary protection implementation for Mars lander missions. It was sponsored and organized by the Exobiology Implementation Team of the U.S./Russian Joint Working Group on Space Biomedical and Life Support Systems. The objective of the workshop was to discuss planetary protection issues for the Russian Mars '94 mission, which is currently under development, as well as for additional future Mars lander missions including the planned Mars '96 and U.S. MESUR Pathfinder and Network missions. A series of invited presentations was made to ensure that workshop participants had access to information relevant to the planned discussions. The topics summarized in this report include exobiology science objectives for Mars exploration, current international policy on planetary protection, planetary protection requirements developed for earlier missions, mission plans and designs for future U.S. and Russian Mars landers, biological contamination of spacecraft components, and techniques for spacecraft bioload reduction. In addition, the recent recommendations of the U.S. Space Studies Board (SSB) on this subject were also summarized. Much of the discussion focused on the recommendations of the SSB. The SSB proposed relaxing the planetary protection requirements for those Mars lander missions that do not contain life detection experiments, but maintaining Viking-like requirements for those missions that do contain life detection experiments. The SSB recommendations were found to be acceptable as a guide for future missions, although many questions and concerns about interpretation were raised and are summarized. Significant among the concerns was the need for more quantitative guidelines to prevent misinterpretation by project offices and better access to and use of the Viking data base of bio-assays to specify microbial burden targets. Among the questions raised were how will the SSB recommendations be integrated with existing

  10. Is Planetary-Scale High Tech Civilization Climatically Sustainable?: The Geophysics v Economics Paradigm War

    Science.gov (United States)

    Hoffert, M.

    2012-12-01

    Climate/energy policy is gridlocked between (1) a geophysics perspective revealing long-term instabilities from continued energy consumption growth, of which the fossil fuel greenhouse an early symptom; and (2) short-term, fossil-fuel energized-rapid-economic-growth-driven policies likely adaptive for hunter-gatherers competing for scarce food, but climatically fatal to planetary-scale economies dependent on agriculture and "energy slaves." Incorporating social science into climate/energy policy formulation has focused on integrated assessment models (IAMs) exploring scenarios (parallel universes making different social choices) depicting the evolution of GDP, energy consumed, the energy technology mixture, land use, greenhouse gas and aerosol emissions, and radiative forcing). Representative concentration pathways (RCP) scenarios developed for the IPCC AR5 report imply 5-10 degree C warming from fossil fuel burning unless unprecedentedly fast decarbonization rates ~ 7 %/yr are implemented from 2020 to 2100. A massive transition to carbon neutrality by midcentury is needed to keep warming use continues growing at 2%/year, fossil-fuel-greenhouse level warming would be generated by heat rejecting in only 200-300 years underscoring that sustainability implies a steady state planetary economy (FIG.2). Evolutionary psychology and neuroeconomics are emergent disciplines that may illuminate the physical v social science paradigm conflict threatening human survivability.

  11. Planetary nebulae: 20 years of Hubble inquiry

    Science.gov (United States)

    Balick, Bruce

    2012-08-01

    The Hubble Space Telescope has served the critical roles of microscope and movie camera in the past 20 years of research on planetary nebulae (``PNe''). We have glimpsed the details of the evolving structures of neutral and ionized post-AGB objects, built ingenious heuristic models that mimic these structures, and constrained most of the relevant physical processes with careful observations and interpretation. We have searched for close physical binary stars with spatial resolution ~50 AU at 1 AU, located jets emerging from the nucleus at speeds up to 2000 km s-1 and matched newly discovered molecular and X-ray emission regions to physical substructures in order to better understand how stellar winds and ionizing radiation interact to form the lovely symmetries that are observed. Ultraviolet spectra of CNO in PNe help to uncover how stars process deep inside AGB stars with unstable nuclear burning zones. HST broadband imaging has been at the forefront of uncovering surprisingly complex wind morphologies produced at the tip of the AGB, and has led to an increasing realization of the potentially vital roles of close binary stars and emerging magnetic fields in shaping stellar winds.

  12. Photogrammetric Processing of Planetary Linear Pushbroom Images Based on Approximate Orthophotos

    Science.gov (United States)

    Geng, X.; Xu, Q.; Xing, S.; Hou, Y. F.; Lan, C. Z.; Zhang, J. J.

    2018-04-01

    It is still a great challenging task to efficiently produce planetary mapping products from orbital remote sensing images. There are many disadvantages in photogrammetric processing of planetary stereo images, such as lacking ground control information and informative features. Among which, image matching is the most difficult job in planetary photogrammetry. This paper designs a photogrammetric processing framework for planetary remote sensing images based on approximate orthophotos. Both tie points extraction for bundle adjustment and dense image matching for generating digital terrain model (DTM) are performed on approximate orthophotos. Since most of planetary remote sensing images are acquired by linear scanner cameras, we mainly deal with linear pushbroom images. In order to improve the computational efficiency of orthophotos generation and coordinates transformation, a fast back-projection algorithm of linear pushbroom images is introduced. Moreover, an iteratively refined DTM and orthophotos scheme was adopted in the DTM generation process, which is helpful to reduce search space of image matching and improve matching accuracy of conjugate points. With the advantages of approximate orthophotos, the matching results of planetary remote sensing images can be greatly improved. We tested the proposed approach with Mars Express (MEX) High Resolution Stereo Camera (HRSC) and Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images. The preliminary experimental results demonstrate the feasibility of the proposed approach.

  13. Galactic planetary nebulae and evolution of their nuclei

    International Nuclear Information System (INIS)

    Khromov, G.S.

    1980-01-01

    The galactic system of planetary nebulae is investigated using previously constructed distance scale and kinematics data. A strong effect of observational selection is established, which has the consequence that with increasing distance, ever brighter and younger objects are observed. More accurate determinations of the spatial and surface densities of the planetary nebulae system are obtained as well as a new estimate of their total number in the Galaxy, which is approximately 200,000. New estimates are also made of the masses of the nebulae, the absolute magnitudes of the nebulae and their nuclei, and other physical parameters of these objects. The spatial and kinematic characteristics of the planetary nebulae indicate that they are objects of the old type I population. It is possible that their remote ancestors are main sequence stars of the type B8-A5-F or as yet unidentified objects of the same galactic subsystem

  14. Alien skies planetary atmospheres from earth to exoplanets

    CERN Document Server

    Pont, Frédéric J

    2014-01-01

    Planetary atmospheres are complex and evolving entities, as mankind is rapidly coming to realise whilst attempting to understand, forecast and mitigate human-induced climate change. In the Solar System, our neighbours Venus and Mars provide striking examples of two endpoints of planetary evolution, runaway greenhouse and loss of atmosphere to space. The variety of extra-solar planets brings a wider angle to the issue: from scorching "hot jupiters'' to ocean worlds, exo-atmospheres explore many configurations unknown in the Solar System, such as iron clouds, silicate rains, extreme plate tectonics, and steam volcanoes. Exoplanetary atmospheres have recently become accessible to observations. This book puts our own climate in the wider context of the trials and tribulations of planetary atmospheres. Based on cutting-edge research, it uses a grand tour of the atmospheres of other planets to shine a new light on our own atmosphere, and its relation with life.

  15. Planetary Gearbox Fault Detection Using Vibration Separation Techniques

    Science.gov (United States)

    Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    Studies were performed to demonstrate the capability to detect planetary gear and bearing faults in helicopter main-rotor transmissions. The work supported the Operations Support and Sustainment (OSST) program with the U.S. Army Aviation Applied Technology Directorate (AATD) and Bell Helicopter Textron. Vibration data from the OH-58C planetary system were collected on a healthy transmission as well as with various seeded-fault components. Planetary fault detection algorithms were used with the collected data to evaluate fault detection effectiveness. Planet gear tooth cracks and spalls were detectable using the vibration separation techniques. Sun gear tooth cracks were not discernibly detectable from the vibration separation process. Sun gear tooth spall defects were detectable. Ring gear tooth cracks were only clearly detectable by accelerometers located near the crack location or directly across from the crack. Enveloping provided an effective method for planet bearing inner- and outer-race spalling fault detection.

  16. NASA's Lunar and Planetary Mapping and Modeling Program

    Science.gov (United States)

    Law, E.; Day, B. H.; Kim, R. M.; Bui, B.; Malhotra, S.; Chang, G.; Sadaqathullah, S.; Arevalo, E.; Vu, Q. A.

    2016-12-01

    NASA's Lunar and Planetary Mapping and Modeling Program produces a suite of online visualization and analysis tools. Originally designed for mission planning and science, these portals offer great benefits for education and public outreach (EPO), providing access to data from a wide range of instruments aboard a variety of past and current missions. As a component of NASA's Science EPO Infrastructure, they are available as resources for NASA STEM EPO programs, and to the greater EPO community. As new missions are planned to a variety of planetary bodies, these tools are facilitating the public's understanding of the missions and engaging the public in the process of identifying and selecting where these missions will land. There are currently three web portals in the program: the Lunar Mapping and Modeling Portal or LMMP (http://lmmp.nasa.gov), Vesta Trek (http://vestatrek.jpl.nasa.gov), and Mars Trek (http://marstrek.jpl.nasa.gov). Portals for additional planetary bodies are planned. As web-based toolsets, the portals do not require users to purchase or install any software beyond current web browsers. The portals provide analysis tools for measurement and study of planetary terrain. They allow data to be layered and adjusted to optimize visualization. Visualizations are easily stored and shared. The portals provide 3D visualization and give users the ability to mark terrain for generation of STL files that can be directed to 3D printers. Such 3D prints are valuable tools in museums, public exhibits, and classrooms - especially for the visually impaired. Along with the web portals, the program supports additional clients, web services, and APIs that facilitate dissemination of planetary data to a range of external applications and venues. NASA challenges and hackathons are also providing members of the software development community opportunities to participate in tool development and leverage data from the portals.

  17. Statistical and physical study of one-sided planetary nebulae.

    Science.gov (United States)

    Ali, A.; El-Nawawy, M. S.; Pfleiderer, J.

    The authors have investigated the spatial orientation of one-sided planetary nebulae. Most of them if not all are interacting with the interstellar medium. Seventy percent of the nebulae in the sample have inclination angles larger than 45° to the Galactic plane and 30% of the inclination angles are less than 45°. Most of the selected objects are old, evolved planetary nebulae with large dimensions, and not far away from the Galactic plane. Seventy-five percent of the objects are within 160 pc from the Galactic plane. The enhanced concavity arc can be explained physically as a result of the 'planetary nebulae-interstellar matter' interaction. The authors discuss the possible effect of the interstellar magnetic field in the concavity regions.

  18. A comparison of Hipparcos parallaxes with planetary nebulae spectroscopic distances

    NARCIS (Netherlands)

    Pottasch, [No Value; Acker, A

    1998-01-01

    The Hipparcos satellite has measured the parallax of a small sample of planetary nebulae. In this paper we consider the results for 3 planetary nebulae (PN) for which spectroscopic distances have also been determined from stellar gravities. These gravities in turn have been derived from profile

  19. Water Partitioning in Planetary Embryos and Protoplanets with Magma Oceans

    Science.gov (United States)

    Ikoma, M.; Elkins-Tanton, L.; Hamano, K.; Suckale, J.

    2018-06-01

    The water content of magma oceans is widely accepted as a key factor that determines whether a terrestrial planet is habitable. Water ocean mass is determined as a result not only of water delivery and loss, but also of water partitioning among several reservoirs. Here we review our current understanding of water partitioning among the atmosphere, magma ocean, and solid mantle of accreting planetary embryos and protoplanets just after giant collisions. Magma oceans are readily formed in planetary embryos and protoplanets in their accretion phase. Significant amounts of water are partitioned into magma oceans, provided the planetary building blocks are water-rich enough. Particularly important but still quite uncertain issues are how much water the planetary building blocks contain initially and how water goes out of the solidifying mantle and is finally degassed to the atmosphere. Constraints from both solar-system explorations and exoplanet observations and also from laboratory experiments are needed to resolve these issues.

  20. Solar system astrophysics planetary atmospheres and the outer solar system

    CERN Document Server

    Milone, Eugene F

    2014-01-01

    The second edition of Solar System Astrophysics: Planetary Atmospheres and the Outer Solar System provides a timely update of our knowledge of planetary atmospheres and the bodies of the outer solar system and their analogs in other planetary systems. This volume begins with an expanded treatment of the physics, chemistry, and meteorology of the atmospheres of the Earth, Venus, and Mars, moving on to their magnetospheres and then to a full discussion of the gas and ice giants and their properties. From here, attention switches to the small bodies of the solar system, beginning with the natural satellites. Then comets, meteors, meteorites, and asteroids are discussed in order, and the volume concludes with the origin and evolution of our solar system. Finally, a fully revised section on extrasolar planetary systems puts the development of our system in a wider and increasingly well understood galactic context. All of the material is presented within a framework of historical importance. This book and its sist...

  1. A bibliography of planetary geology principal investigators and their associates, 1982 - 1983

    Science.gov (United States)

    Plescia, J. B.

    1984-01-01

    This bibliography cites recent publications by principal investigators and their associates, supported through NASA's Office of Space Science and Applications, Earth and Planetary Exploration Division, Planetary Geology Program. It serves as a companion piece to NASA TM-85127, ""Reports of Planetary Programs, 1982". Entries are listed under the following subject areas: solar system, comets, asteroids, meteorites and small bodies; geologic mapping, geomorphology, and stratigraphy; structure, tectonics, and planetary and satellite evolutions; impact craters; volcanism; fluvial, mass wasting, glacial and preglacial studies; Eolian and Arid climate studies; regolith, volatiles, atmosphere, and climate, radar; remote sensing and photometric studies; and cartography, photogrammetry, geodesy, and altimetry. An author index is provided.

  2. Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

    Science.gov (United States)

    Klein, Richard C.; Fusaro, Robert L.; Dimofte, Florin

    2012-01-01

    NASA s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments. Current drive systems use gears with various configurations of teeth. These gears must be lubricated with oil (or grease) and must have some sort of a lubricant resupply system. For drive systems, oil poses problems such as evaporation, becoming too viscous and eventually freezing at cold temperatures, being too thin to lubricate at high temperatures, being degraded by the radiation environment, being contaminated by the regolith (soil), and if vaporized (and not sealed), it will contaminate the regolith. Thus, it may not be advisable or even possible to use oil because of these limitations. An oil-less, compact traction vehicle drive is a drive designed for use in hostile environments like those that will be encountered on planetary surfaces. Initially, traction roller tests in vacuum were conducted to obtain traction and endurance data needed for designing the drives. From that data, a traction drive was designed that would fit into a prototype lunar rover vehicle, and this design data was used to construct several traction drives. These drives were then tested in air to determine their performance characteristics, and if any final corrections to the designs were necessary. A limitation with current speed reducer systems such as planetary gears and harmonic drives is the high-contact stresses that occur at tooth engagement and in the harmonic drive wave generator interface. These high stresses induce high wear of solid

  3. The Vibration Sensors Optimum Mounting Analysis at Planetary Reduction Gearmotor Vibration Diagnostics

    OpenAIRE

    Ļitvinovs, D

    2008-01-01

    Due to the specific mechanical peculiarities, planetary reduction gearmotors were and remain the most progressive types of reduction gearboxes for industry application. Compactness, small specific gravity and, simultaneously, possibility to pass the increased loadings – here what planetary reduction gearmotors are attractive for developers and customers. Because of planetary reduction gearmotors increased amount applying in industry, increases the requirements in their diagnostics. For this p...

  4. Solar Variability and Planetary Climates

    CERN Document Server

    Calisesi, Y; Gray, L; Langen, J; Lockwood, M

    2007-01-01

    Variations in solar activity, as revealed by variations in the number of sunspots, have been observed since ancient times. To what extent changes in the solar output may affect planetary climates, though, remains today more than ever a subject of controversy. In 2000, the SSSI volume on Solar Variability and Climate reviewed the to-date understanding of the physics of solar variability and of the associated climate response. The present volume on Solar Variability and Planetary Climates provides an overview of recent advances in this field, with particular focus at the Earth's middle and lower atmosphere. The book structure mirrors that of the ISSI workshop held in Bern in June 2005, the collection of invited workshop contributions and of complementary introductory papers synthesizing the current understanding in key research areas such as middle atmospheric processes, stratosphere-troposphere dynamical coupling, tropospheric aerosols chemistry, solar storm influences, solar variability physics, and terrestri...

  5. Spreading the passion for scientifically useful planetary observations

    Science.gov (United States)

    Kardasis, E.; Vourliotis, E.; Bellias, I.; Maravelias, G.; Vakalopoulos, E.; Papadeas, P.; Marouda, K.; Voutyras, O.

    2015-10-01

    Τhe "March 2015 - Planetary Observation Project (POP)" was a series of talks and hands-on workshops focused on planetary observation organized in March 2015 by the planetary section of the Hellenic Amateur Astronomy Association. Building on our previous experience (Voutyras et al. 2013), which also includes more than 500 attendants in our 2013-2014 series of lectures in Astronomy, we identified that there is a lack of more focused lectures/workshops on observing techniques. In particular, POP's structure included two talks and two workshops aiming to inspire and educate astronomy enthusiasts. The talks tried to stimulate the participants about the importance of ground-based observations by presenting the most current scientific news and puzzling problems that we are facing in the observation of planets. During the hands-on workshops the beauty of planetary observation was used to inspire participants. However, we trained participants on observing techniques and image processing to enable them to produce scientifically useful results. All POP's events were open to the public and free, meaning both out-of-charge and freely available material provided to the participants (through our website). The project offered attendants unique experiences that may have a significant impact with potential lifelong benefits. In this work we present an overview of the project structure that may work as a prototype for similar outreach programs.

  6. Analysis of solar radiation transfer: A method to estimate the porosity of a plastic shading net

    International Nuclear Information System (INIS)

    Abdel-Ghany, A.M.; Al-Helal, I.M.

    2011-01-01

    Plastic nets with opaque threads are frequently used for shading agricultural structures under high solar radiation conditions. A parameter that is often used to define a net is the net porosity (Π). Value of Π is usually estimated by one of three methods: image processing, direct beam transmittance, or solar radiation balance (hereafter radiation balance). Image processing is a rather slow process because it requires scanning the net sample at high resolution. The direct beam transmittance and radiation balance methods greatly overestimate Π because some of the solar radiation incident on the thread surfaces is forward scattered and add a considerable amount of radiation to that transmitted from the net pores directly. In this study, the radiation balance method was modified to estimate Π precisely. The amount of solar radiation scattered forward on the thread surfaces was estimated separately. Thus, the un-scattered solar radiation transmitted from the net pores directly, which describes the net porosity, Π could be estimated. This method, in addition to the image processing and the direct beam transmittance methods were used to estimate Π for different types of nets that are commonly used for shading structures in summer. Values of Π estimated by using the proposed method were in good accordance with those measured by the image processing method at a resolution of 4800 dpi. The direct beam transmittance and the radiation balance methods resulted in overestimation errors in the values of Π. This error strongly depends on the color of the net. The estimated errors were +14% for a green net and +37% for a white net when using the radiation balance method, and were +16% and +38%, respectively, when using the direct beam transmittance method. In the image processing method, a resolution of 2400 dpi is sufficient to estimate Π precisely and the higher resolutions showed no significant effect on the value of Π.

  7. Robots and Humans in Planetary Exploration: Working Together?

    Science.gov (United States)

    Landis, Geoffrey A.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Today's approach to human-robotic cooperation in planetary exploration focuses on using robotic probes as precursors to human exploration. A large portion of current NASA planetary surface exploration is focussed on Mars, and robotic probes are seen as precursors to human exploration in: Learning about operation and mobility on Mars; Learning about the environment of Mars; Mapping the planet and selecting landing sites for human mission; Demonstration of critical technology; Manufacture fuel before human presence, and emplace elements of human-support infrastructure

  8. Fluvial geomorphology on Earth-like planetary surfaces: A review.

    Science.gov (United States)

    Baker, Victor R; Hamilton, Christopher W; Burr, Devon M; Gulick, Virginia C; Komatsu, Goro; Luo, Wei; Rice, James W; Rodriguez, J A P

    2015-09-15

    Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn's moon Titan). In other cases, as on Mercury, Venus, Earth's moon, and Jupiter's moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn's moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry.

  9. Spatial solar radiation distribution analysis in afforestation at horqin desert, China

    International Nuclear Information System (INIS)

    Hao, A.; Haraguchi, T.; Nakano, Y.; Amaya, T.

    2007-01-01

    Forestation is one of the effective ways to prevent the desertification. This study was conducted to evaluate the effects of big project of forestation going on at Naimanki, Horqin Desert in China. First, a simulation model was proposed to estimate solar radiation environment in the poplars forest. Second, using fisheye-photographs taken at several points on the soil surface between tree rows, gap space of the canopy was calculated with applying the Gap Light Analyzer (GLA). Third, the gap space data were used for simulating direct radiation, diffused radiation and scattered radiation at different points on the soil surface. Fourth, the accuracy of simulation model was checked by comparing the estimated solar radiations at four points on the soil surface with the observation. The estimated values showed good agreement with the observation. Once the fisheye-photographs were taken at any points on the soil surface, daily fluctuations of solar radiation in the forestation can be calculated. Solar radiation acts main role on energy balance, heat balance and water balance phenomena in the forestation. The proposed method would be effectively used for evaluating the environmental modification brought by the forestation in the desert

  10. Vision and Voyages: Lessons Learned from the Planetary Decadal Survey

    Science.gov (United States)

    Squyres, S. W.

    2015-12-01

    The most recent planetary decadal survey, entitled Vision and Voyages for Planetary Science in the Decade 2013-2022, provided a detailed set of priorities for solar system exploration. Those priorities drew on broad input from the U.S. and international planetary science community. Using white papers, town hall meetings, and open meetings of the decadal committees, community views were solicited and a consensus began to emerge. The final report summarized that consensus. Like many past decadal reports, the centerpiece of Vision and Voyages was a set of priorities for future space flight projects. Two things distinguished this report from some previous decadals. First, conservative and independent cost estimates were obtained for all of the projects that were considered. These independent cost estimates, rather than estimates generated by project advocates, were used to judge each project's expected science return per dollar. Second, rather than simply accepting NASA's ten-year projection of expected funding for planetary exploration, decision rules were provided to guide program adjustments if actual funding did not follow projections. To date, NASA has closely followed decadal recommendations. In particular, the two highest priority "flagship" missions, a Mars rover to collect samples for return to Earth and a mission to investigate a possible ocean on Europa, are both underway. The talk will describe the planetary decadal process in detail, and provide a more comprehensive assessment of NASA's response to it.

  11. The Planetary Terrestrial Analogues Library (PTAL)

    Science.gov (United States)

    Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

    2018-04-01

    The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

  12. On the evolution of central stars of planetary nebulae

    International Nuclear Information System (INIS)

    Yahel, R.Z.

    1977-01-01

    The evolution of nuclei of planetary nebulae has been calculated from the end of the ejection stage that produces the nebulae to the white dwarf stage. The structure of the central star is in agreement with the general picture of Finzi (1973) about the mass ejection from the progenitors of planetary nebulae. It has been found that in order to obtain evolutionary track consistent with the Harman-Seaton track (O'Dell, 1968) one has to assume that the masses of the nuclei stars are less than approximately 0.7 solar masses. The calculated evolutionary time scale of the central stars of planetary nebulae is approximately 2 x 10 4 yr. This time scale is negatively correlated with the stellar mass: the heavier the stellar mass, the shorter the evolutionary time scale. (Auth.)

  13. Planetary Balloon-Based Science Platform Evaluation and Program Implementation

    Science.gov (United States)

    Dankanich, John W.; Kremic, Tibor; Hibbitts, Karl; Young, Eliot F.; Landis, Rob

    2016-01-01

    This report describes a study evaluating the potential for a balloon-based optical telescope as a planetary science asset to achieve decadal class science. The study considered potential science achievable and science traceability relative to the most recent planetary science decadal survey, potential platform features, and demonstration flights in the evaluation process. Science Potential and Benefits: This study confirms the cost the-benefit value for planetary science purposes. Forty-four (44) important questions of the decadal survey are at least partially addressable through balloon based capabilities. Planetary science through balloon observations can provide significant science through observations in the 300 nm to 5 m range and at longer wavelengths as well. Additionally, balloon missions have demonstrated the ability to progress from concept to observation to publication much faster than a space mission increasing the speed of science return. Planetary science from a balloon-borne platform is a relatively low-cost approach to new science measurements. This is particularly relevant within a cost-constrained planetary science budget. Repeated flights further reduce the cost of the per unit science data. Such flights offer observing time at a very competitive cost. Another advantage for planetary scientists is that a dedicated asset could provide significant new viewing opportunities not possible from the ground and allow unprecedented access to observations that cannot be realized with the time allocation pressures faced by current observing assets. In addition, flight systems that have a relatively short life cycle and where hardware is generally recovered, are excellent opportunities to train early career scientists, engineers, and project managers. The fact that balloon-borne payloads, unlike space missions, are generally recovered offers an excellent tool to test and mature instruments and other space craft systems. Desired Gondola Features: Potential

  14. Lunar and planetary surface conditions advances in space science and technology

    CERN Document Server

    Weil, Nicholas A

    1965-01-01

    Lunar and Planetary Surface Conditions considers the inferential knowledge concerning the surfaces of the Moon and the planetary companions in the Solar System. The information presented in this four-chapter book is based on remote observations and measurements from the vantage point of Earth and on the results obtained from accelerated space program of the United States and U.S.S.R. Chapter 1 presents the prevalent hypotheses on the origin and age of the Solar System, followed by a brief description of the methods and feasibility of information acquisition concerning lunar and planetary data,

  15. Past and future of radio occultation studies of planetary atmospheres

    Science.gov (United States)

    Eshleman, Von R.; Hinson, David P.; Tyler, G. Leonard; Lindal, Gunnar F.

    1987-01-01

    Measurements of radio waves that have propagated through planetary atmospheres have provided exploratory results on atmospheric constituents, structure, dynamics, and ionization for Venus, Mars, Titan, Jupiter, Saturn, and Uranus. Highlights of past results are reviewed in order to define and illustrate the potential of occultation and related radio studies in future planetary missions.

  16. Preliminary analysis of surface radiation measurements recorded at the Nansen ice sheet (Antarctica)

    International Nuclear Information System (INIS)

    Bonafe', U.; Dalpane, E.; Georgiadis, T.; Pitacco, A.

    1996-01-01

    An experiment on radiation and surface energy balance was conducted during the 9. Italian expedition in Antarctica at the Nancen ice sheet, a glacier situated close to the Italian base at Terra Nova Bay, to correlate surface balances to the formation and development of katabatic winds. Measurements were taken by radiometers covering the whole spectra of solar and terrestrial emissions and by fast sensors of atmospheric wind velocity and humidity for the application of the eddy correlation technique. A preliminary analysis of the radiometric data collected in order to quantify the major components of radiative energy balance during the Antarctic summer in clear sky conditions is reported and discussed. The findings show the very low available energy (mean about 1 W/m 2 ), in terms of net radiation, for the physical processes such as sensible- and latent-heat fluxes. Long-wave radiation balance was applied to estimate the reliability of the Swinbank's parametrization, relative to general conditions of the atmosphere

  17. Robo-AO Kepler Survey. IV. The Effect of Nearby Stars on 3857 Planetary Candidate Systems

    Science.gov (United States)

    Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Riddle, Reed; Duev, Dmitry A.; Howard, Ward; Jensen-Clem, Rebecca; Kulkarni, S. R.; Morton, Tim; Salama, Maïssa

    2018-04-01

    We present the overall statistical results from the Robo-AO Kepler planetary candidate survey, comprising of 3857 high-angular resolution observations of planetary candidate systems with Robo-AO, an automated laser adaptive optics system. These observations reveal previously unknown nearby stars blended with the planetary candidate host stars that alter the derived planetary radii or may be the source of an astrophysical false positive transit signal. In the first three papers in the survey, we detected 440 nearby stars around 3313 planetary candidate host stars. In this paper, we present observations of 532 planetary candidate host stars, detecting 94 companions around 88 stars; 84 of these companions have not previously been observed in high resolution. We also report 50 more-widely separated companions near 715 targets previously observed by Robo-AO. We derive corrected planetary radius estimates for the 814 planetary candidates in systems with a detected nearby star. If planetary candidates are equally likely to orbit the primary or secondary star, the radius estimates for planetary candidates in systems with likely bound nearby stars increase by a factor of 1.54, on average. We find that 35 previously believed rocky planet candidates are likely not rocky due to the presence of nearby stars. From the combined data sets from the complete Robo-AO KOI survey, we find that 14.5 ± 0.5% of planetary candidate hosts have a nearby star with 4″, while 1.2% have two nearby stars, and 0.08% have three. We find that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of Jupiter-sized planet candidates have detected nearby stars.

  18. Balancing radiation risks and benefits of cardiac imaging: challenges for developed countries

    International Nuclear Information System (INIS)

    Einstein, A.J.; Balter, S.; Bernheim, A.; Brenner, D.J.

    2008-01-01

    Full text: Cardiovascular disease remains the leading cause of death in the US, EU, Canada, Australia, and New Zealand, although coronary disease mortality has decreased due to improvements in prevention, diagnosis, and treatment. In many developed countries, most cardiologists now perform procedures involving radiopharmaceuticals, CT, or fluoroscopy. Their increased utilization, while contributing to improved care for patients with known or suspected heart disease, has been accompanied by a sharp increase in collective doses from medical radiation. E.g., an estimated ∼ 10% (∼ 0.6 mSv/person/y) of the collective dose to the US population is now attributed to nuclear stress tests. Radiation risk from any modality is highly dependent on patient age and gender. Cardiologists, like most non-radiologists, have had limited training in the safe use of radiation and are generally unaware of such facts. While one encouraging sign has been the development of appropriateness criteria for various cardiac imaging modalities, much work remains to advance radiological protection for the tens of millions of patients each year who receive cardiac imaging studies. Here we address current efforts to balance benefits of cardiac imaging with radiation risks, dose-reduction strategies, and future desiderata. General themes are improvements in technology, education, clinical standards, and reimbursement policies for these examinations. The vast majority of nuclear cardiology studies are performed using SPECT, and the radiopharmaceuticals used most widely are 99m Tc sestamibi and tetrofosmin, and 201 Tl. Effective doses are considerably higher for standard injected activities of 201 Tl than for 99m Tc agents, and the highest doses, ∼ 24 mSv, are associated with dual isotope (rest 201 Tl, stress 99m Tc) protocols. E.g., in the US, 1/4 of nuclear stress tests are still performed using dual isotope protocols, a practice fostered by current structuring of reimbursement. Although most

  19. Visual lunar and planetary astronomy

    CERN Document Server

    Abel, Paul G

    2013-01-01

    With the advent of CCDs and webcams, the focus of amateur astronomy has to some extent shifted from science to art. The object of many amateur astronomers is now to produce “stunning images” that, although beautiful, are not intended to have scientific merit. Paul Abel has been addressing this issue by promoting visual astronomy wherever possible – at talks to astronomical societies, in articles for popular science magazines, and on BBC TV’s The Sky at Night.   Visual Lunar and Planetary Astronomy is a comprehensive modern treatment of visual lunar and planetary astronomy, showing that even in the age of space telescopes and interplanetary probes it is still possible to contribute scientifically with no more than a moderately priced commercially made astronomical telescope.   It is believed that imaging and photography is somehow more objective and more accurate than the eye, and this has led to a peculiar “crisis of faith” in the human visual system and its amazing processing power. But by anal...

  20. Annual review of earth and planetary sciences. Volume 8

    International Nuclear Information System (INIS)

    Donath, F.A.; Stehli, F.G.; Wetherill, G.W.

    1980-01-01

    Papers are presented on the geochemistry of evaporitic lacustrine deposits, the deformation of mantle rocks, the dynamics of sudden stratospheric warmings, the equatorial undercurrent, geomorphological processes on planetary surfaces, and rare earth elements in petrogenetic studies of igneous systems. Consideration is also given to evolutionary patterns in early Cenozoic animals, the origin and evolution of planetary atmospheres, the moons of Mars, and refractory inclusions in the Allende meteorite

  1. MPLNET V3 Cloud and Planetary Boundary Layer Detection

    Science.gov (United States)

    Lewis, Jasper R.; Welton, Ellsworth J.; Campbell, James R.; Haftings, Phillip C.

    2016-01-01

    The NASA Micropulse Lidar Network Version 3 algorithms for planetary boundary layer and cloud detection are described and differences relative to the previous Version 2 algorithms are highlighted. A year of data from the Goddard Space Flight Center site in Greenbelt, MD consisting of diurnal and seasonal trends is used to demonstrate the results. Both the planetary boundary layer and cloud algorithms show significant improvement of the previous version.

  2. Mission Implementation Constraints on Planetary Muon Radiography

    Science.gov (United States)

    Jones, Cathleen E.; Kedar, Sharon; Naudet, Charles; Webb, Frank

    2011-01-01

    Cost: Use heritage hardware, especially use a tested landing system to reduce cost (Phoenix or MSL EDL stage). The sky crane technology delivers higher mass to the surface and enables reaching targets at higher elevation, but at a higher mission cost. Rover vs. Stationary Lander: Rover-mounted instrument enables tomography, but the increased weight of the rover reduces the allowable payload weight. Mass is the critical design constraint for an instrument for a planetary mission. Many factors that are minor factors or do not enter into design considerations for terrestrial operation are important for a planetary application. (Landing site, diurnal temperature variation, instrument portability, shock/vibration)

  3. Power balance and loss mechanism analysis in RF transmit coil arrays.

    Science.gov (United States)

    Kuehne, Andre; Goluch, Sigrun; Waxmann, Patrick; Seifert, Frank; Ittermann, Bernd; Moser, Ewald; Laistler, Elmar

    2015-10-01

    To establish a framework for transmit array power balance calculations based on power correlation matrices to accurately quantify the loss contributions from different mechanisms such as coupling, lumped components, and radiation. Starting from Poynting's theorem, power correlation matrices are derived for all terms in the power balance, which is formulated as a matrix equation. Finite-difference time-domain simulations of two 7 T eight-channel head array coils at 297.2 MHz are used to verify the theoretical considerations and demonstrate their application. Care is taken to accurately incorporate all loss mechanisms. The power balance for static B1 phase shims as well as two-dimensional spatially selective transmit SENSE pulses is shown. The simulated power balance shows an excellent agreement with theory, with a maximum power imbalance of less than 0.11%. Power loss contributions from the different loss mechanisms vary significantly between the investigated setups, and depending on the excitation mode imposed on the coil. The presented approach enables a straightforward loss evaluation for an arbitrary excitation of transmit coil arrays. Worst-case power imbalance and losses are calculated in a straightforward manner. This allows for deeper insight into transmit array loss mechanisms, incorporation of radiated power components in specific absorption rate calculations and verification of electromagnetic simulations. © 2014 Wiley Periodicals, Inc.

  4. Developing the Planetary Science Virtual Observatory

    Science.gov (United States)

    Erard, Stéphane; Cecconi, Baptiste; Le Sidaner, Pierre; Henry, Florence; Chauvin, Cyril; Berthier, Jérôme; André, Nicolas; Génot, Vincent; Schmitt, Bernard; Capria, Teresa; Chanteur, Gérard

    2015-08-01

    In the frame of the Europlanet-RI program, a prototype Virtual Observatory dedicated to Planetary Science has been set up. Most of the activity was dedicated to the definition of standards to handle data in this field. The aim was to facilitate searches in big archives as well as sparse databases, to make on-line data access and visualization possible, and to allow small data providers to make their data available in an interoperable environment with minimum effort. This system makes intensive use of studies and developments led in Astronomy (IVOA), Solar Science (HELIO), and space archive services (IPDA).The current architecture connects existing data services with IVOA or IPDA protocols whenever relevant. However, a more general standard has been devised to handle the specific complexity of Planetary Science, e.g. in terms of measurement types and coordinate frames. This protocol, named EPN-TAP, is based on TAP and includes precise requirements to describe the contents of a data service (Erard et al Astron & Comp 2014). A light framework (DaCHS/GAVO) and a procedure have been identified to install small data services, and several hands-on sessions have been organized already. The data services are declared in standard IVOA registries. Support to new data services in Europe will be provided during the proposed Europlanet H2020 program, with a focus on planetary mission support (Rosetta, Cassini…).A specific client (VESPA) has been developed at VO-Paris (http://vespa.obspm.fr). It is able to use all the mandatory parameters in EPN-TAP, plus extra parameters from individual services. A resolver for target names is also available. Selected data can be sent to VO visualization tools such as TOPCAT or Aladin though the SAMP protocol.Future steps will include the development of a connection between the VO world and GIS tools, and integration of heliophysics, planetary plasma and reference spectroscopic data.The EuroPlaNet-RI project was funded by the European

  5. PLANETARY NEBULAE IN FACE-ON SPIRAL GALAXIES. II. PLANETARY NEBULA SPECTROSCOPY

    International Nuclear Information System (INIS)

    Herrmann, Kimberly A.; Ciardullo, Robin

    2009-01-01

    As the second step in our investigation of the mass-to-light ratio of spiral disks, we present the results of a spectroscopic survey of planetary nebulae (PNe) in five nearby, low-inclination galaxies: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), and M101 (NGC 5457). Using 50 setups of the WIYN/Hydra and Blanco/Hydra spectrographs, and 25 observations with the Hobby-Eberly Telescope's Medium Resolution Spectrograph, we determine the radial velocities of 99, 102, 162, 127, and 48 PNe, respectively, to a precision better than 15 km s -1 . Although the main purpose of this data set is to facilitate dynamical mass measurements throughout the inner and outer disks of large spiral galaxies, our spectroscopy has other uses as well. Here, we co-add these spectra to show that, to first order, the [O III] and Balmer line ratios of PNe vary little over the top ∼1.5 mag of the PN luminosity function. The only obvious spectral change occurs with [N II], which increases in strength as one proceeds down the luminosity function. We also show that typical [O III]-bright planetaries have E(B - V) ∼ 0.2 of circumstellar extinction, and that this value is virtually independent of [O III] luminosity. We discuss the implications this has for understanding the population of PN progenitors.

  6. Measuring planetary neutron albedo fluxes by remote gamma-ray sensing

    International Nuclear Information System (INIS)

    Haines, E.L.; Metzger, A.E.

    1984-01-01

    A remote-sensing γ-ray spectrometer (GRS) is capable of measuring planetary surface composition through the detection of characteristic gamma rays. In addition, the planetary neutron leakage flux may be detected by means of a thin neutron absorber surrounding the γ-ray detector which converts the neutron flux into a γ-ray flux having a unique energy signature. The γ rays representing the neutron flux are observed against interference consisting of cosmic γ rays, planetary continuum and line emission, and a variety of gamma rays arising from cosmic-ray particle interactions with the γ-ray spectrometer and spacecraft (SC). In this paper the amplitudes of planetary and non-planetary neutron fluxes are assessed and their impact on the sensitivity of measurement is calculated for a lunar orbiter mission and a comet nucleus rendezvous mission. For a 100 h observation period from an altitude of 100 km, a GRS on a lunar orbiter can detect a thermal neutron albedo flux as low as 0.002 cm -2 s -1 and measure the expected flux of approx.=0.6 cm -2 s -1 with an uncertainty of 0.001 cm -2 s -1 . A GRS rendezvousing with a comet at a distance equal to the radius of the comet's nucleus, again for a 100 h observation time, should detect a thermal neutron albedo flux at a level of 0.006 cm -2 s -1 and measure the expected flux of approx.=0.4 cm -2 s -1 with an uncertainty of 0.004 cm -2 s -1 . Mapping the planetary neutron flux jointly with the direct detection of H will not only provide a more accurate model for translating observed γ-ray fluxes into concentrations but will also extend the effective sampling depth and should provide a capability for simple stratigraphic modeling of hydrogen. (orig.)

  7. Application of the MCMC Method for the Calibration of DSMC Parameters to NASA EAST Results for Ionizing, Radiating Hypersonic Flows

    Data.gov (United States)

    National Aeronautics and Space Administration — The reentry of a vehicle into a planetary atmosphere creates extreme Mach number conditions which produce a weakly ionized plasma and radiation. The greatest...

  8. Prostate Cancer (Radiation Therapy)

    Science.gov (United States)

    ... be considered carefully, balancing the advantages against the disadvantages as they relate to the individual man's age, ... therapy with photon or x-rays: Uses advanced technology to tailor the x-ray or photon radiation ...

  9. Interoperability In The New Planetary Science Archive (PSA)

    Science.gov (United States)

    Rios, C.; Barbarisi, I.; Docasal, R.; Macfarlane, A. J.; Gonzalez, J.; Arviset, C.; Grotheer, E.; Besse, S.; Martinez, S.; Heather, D.; De Marchi, G.; Lim, T.; Fraga, D.; Barthelemy, M.

    2015-12-01

    As the world becomes increasingly interconnected, there is a greater need to provide interoperability with software and applications that are commonly being used globally. For this purpose, the development of the new Planetary Science Archive (PSA), by the European Space Astronomy Centre (ESAC) Science Data Centre (ESDC), is focused on building a modern science archive that takes into account internationally recognised standards in order to provide access to the archive through tools from third parties, for example by the NASA Planetary Data System (PDS), the VESPA project from the Virtual Observatory of Paris as well as other international institutions. The protocols and standards currently being supported by the new Planetary Science Archive at this time are the Planetary Data Access Protocol (PDAP), the EuroPlanet-Table Access Protocol (EPN-TAP) and Open Geospatial Consortium (OGC) standards. The architecture of the PSA consists of a Geoserver (an open-source map server), the goal of which is to support use cases such as the distribution of search results, sharing and processing data through a OGC Web Feature Service (WFS) and a Web Map Service (WMS). This server also allows the retrieval of requested information in several standard output formats like Keyhole Markup Language (KML), Geography Markup Language (GML), shapefile, JavaScript Object Notation (JSON) and Comma Separated Values (CSV), among others. The provision of these various output formats enables end-users to be able to transfer retrieved data into popular applications such as Google Mars and NASA World Wind.

  10. Emission lines of Mg2 and Ca2 in planetary nebulae

    International Nuclear Information System (INIS)

    Gurzadyan, G.A.

    1979-01-01

    Conditions of exciting resonance lines in the emission of ionized magnesium (lambda lambda 2796+2803 Mg2) and calcium (lambda lambda 3934+3968 Ca2) in planetary nebulae have been analyzed. It is shown that the allowed lines are excited with the same mechanism, as the forbidden lines, i.e. inelastic electron collisions, but not with common fluorescence. The emission line lambda 2800 Mg2 of enough force can be observed only in the spectra of planetary nebulae with mean excitation (IC 2149) as well as in the spectra of diffuse nebulae. The line must not be observed in high-excited planetary nebulae (NGC 7026, 7662). The absence of emission lines H and K Ca2 in planetary nebulae spectra results from the fact, that their expected intensity is by 3-4 orders less than the intensity of the line lambda 2800 Mg2 or Hsub(β) hydrogen

  11. Summary and abstracts of the Planetary Data Workshop, June 2012

    Science.gov (United States)

    Gaddis, Lisa R.; Hare, Trent; Beyer, Ross

    2014-01-01

    The recent boom in the volume of digital data returned by international planetary science missions continues to both delight and confound users of those data. In just the past decade, the Planetary Data System (PDS), NASA’s official archive of scientific results from U.S. planetary missions, has seen a nearly 50-fold increase in the amount of data and now serves nearly half a petabyte. In only a handful of years, this volume is expected to approach 1 petabyte (1,000 terabytes or 1 quadrillion bytes). Although data providers, archivists, users, and developers have done a creditable job of providing search functions, download capabilities, and analysis and visualization tools, the new wealth of data necessitates more frequent and extensive discussion among users and developers about their current capabilities and their needs for improved and new tools. A workshop to address these and other topics, “Planetary Data: A Workshop for Users and Planetary Software Developers,” was held June 25–29, 2012, at Northern Arizona University (NAU) in Flagstaff, Arizona. A goal of the workshop was to present a summary of currently available tools, along with hands-on training and how-to guides, for acquiring, processing and working with a variety of digital planetary data. The meeting emphasized presentations by data users and mission providers during days 1 and 2, and developers had the floor on days 4 and 5 using an “unconference” format for day 5. Day 3 featured keynote talks by Laurence Soderblom (U.S. Geological Survey, USGS) and Dan Crichton (Jet Propulsion Laboratory, JPL) followed by a panel discussion, and then research and technical discussions about tools and capabilities under recent or current development. Software and tool demonstrations were held in break-out sessions in parallel with the oral session. Nearly 150 data users and developers from across the globe attended, and 22 National Aeronautics and space Administration (NASA) and non-NASA data providers

  12. Research of Planetary Gear Fault Diagnosis Based on Permutation Entropy of CEEMDAN and ANFIS

    NARCIS (Netherlands)

    Kuai, Moshen; Cheng, Gang; Pang, Y.; Li, Yong

    2018-01-01

    For planetary gear has the characteristics of small volume, light weight and large transmission ratio, it is widely used in high speed and high power mechanical system. Poor working conditions result in frequent failures of planetary gear. A method is proposed for diagnosing faults in planetary gear

  13. Studying effects of non-equilibrium radiative transfer via HPC

    Energy Technology Data Exchange (ETDEWEB)

    Holladay, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-24

    This report presents slides on Ph.D. Research Goals; Local Thermodynamic Equilibrium (LTE) Implications; Calculating an Opacity; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Opacity: Pictographic Representation; Collisional Radiative Modeling; Radiative and Collisional Excitation; Photo and Electron Impact Ionization; Autoionization; The Rate Matrix; Example: Total Photoionization rate; The Rate Coefficients; inlinlte version 1.1; inlinlte: Verification; New capabilities: Rate Matrix – Flexibility; Memory Option Comparison; Improvements over previous DCA solver; Inter- and intra-node load balancing; Load Balance – Full Picture; Load Balance – Full Picture; Load Balance – Internode; Load Balance – Scaling; Description; Performance; xRAGE Simulation; Post-process @ 2hr; Post-process @ 4hr; Post-process @ 8hr; Takeaways; Performance for 1 realization; Motivation for QOI; Multigroup Er; Transport and NLTE large effects (1mm, 1keV); Transport large effect, NLTE lesser (1mm, 750eV); Blastwave Diagnostici – Description & Performance; Temperature Comparison; NLTE has effect on dynamics at wall; NLTE has lesser effect in the foam; Global Takeaways; The end.

  14. A New Model of the Fractional Order Dynamics of the Planetary Gears

    Directory of Open Access Journals (Sweden)

    Vera Nikolic-Stanojevic

    2013-01-01

    Full Text Available A theoretical model of planetary gears dynamics is presented. Planetary gears are parametrically excited by the time-varying mesh stiffness that fluctuates as the number of gear tooth pairs in contact changes during gear rotation. In the paper, it has been indicated that even the small disturbance in design realizations of this gear cause nonlinear properties of dynamics which are the source of vibrations and noise in the gear transmission. Dynamic model of the planetary gears with four degrees of freedom is used. Applying the basic principles of analytical mechanics and taking the initial and boundary conditions into consideration, it is possible to obtain the system of equations representing physical meshing process between the two or more gears. This investigation was focused to a new model of the fractional order dynamics of the planetary gear. For this model analytical expressions for the corresponding fractional order modes like one frequency eigen vibrational modes are obtained. For one planetary gear, eigen fractional modes are obtained, and a visualization is presented. By using MathCAD the solution is obtained.

  15. Planetary submillimeter spectroscopy

    Science.gov (United States)

    Klein, M. J.

    1988-01-01

    The aim is to develop a comprehensive observational and analytical program to study solar system physics and meterology by measuring molecular lines in the millimeter and submillimeter spectra of planets and comets. A primary objective is to conduct observations with new JPL and Caltech submillimeter receivers at the Caltech Submillimeter Observatory (CSO) on Mauna Kea, Hawaii. A secondary objective is to continue to monitor the time variable planetary phenomena (e.g., Jupiter and Uranus) at centimeter wavelength using the NASA antennas of the Deep Space Network (DSN).

  16. Smart Rotorcraft Field Assistants for Terrestrial and Planetary Science

    Science.gov (United States)

    Young, Larry A.; Aiken, Edwin W.; Briggs, Geoffrey A.

    2004-01-01

    Field science in extreme terrestrial environments is often difficult and sometimes dangerous. Field seasons are also often short in duration. Robotic field assistants, particularly small highly mobile rotary-wing platforms, have the potential to significantly augment a field season's scientific return on investment for geology and astrobiology researchers by providing an entirely new suite of sophisticated field tools. Robotic rotorcraft and other vertical lift planetary aerial vehicle also hold promise for supporting planetary science missions.

  17. Enviromnental Control and Life Support Systems for Mars Missions - Issues and Concerns for Planetary Protection

    Science.gov (United States)

    Barta, Daniel J.; Anderson, Molly S.; Lange, Kevin

    2015-01-01

    Planetary protection represents an additional set of requirements that generally have not been considered by developers of technologies for Environmental Control and Life Support Systems (ECLSS). Planetary protection guidelines will affect the kind of operations, processes, and functions that can take place during future human planetary exploration missions. Ultimately, there will be an effect on mission costs, including the mission trade space when planetary protection requirements begin to drive vehicle deisgn in a concrete way. Planetary protection requirements need to be considered early in technology development and mission programs in order to estimate these impacts and push back on requirements or find efficient ways to perform necessary functions. It is expected that planetary protection will be a significant factor during technology selection and system architecture design for future missions.

  18. Planetary mapping—The datamodel's perspective and GIS framework

    Science.gov (United States)

    van Gasselt, S.; Nass, A.

    2011-09-01

    Demands for a broad range of integrated geospatial data-analysis tools and methods for planetary data organization have been growing considerably since the late 1990s when a plethora of missions equipped with new instruments entered planetary orbits or landed on the surface. They sent back terabytes of new data which soon became accessible for the scientific community and public and which needed to be organized. On the terrestrial side, issues of data access, organization and utilization for scientific and economic analyses are handled by using a range of well-established geographic information systems (GIS) that also found their way into the field of planetary sciences in the late 1990s. We here address key issues concerning the field of planetary mapping by making use of established GIS environments and discuss methods of addressing data organization and mapping requirements by using an easily integrable datamodel that is - for the time being - designed as file-geodatabase (FileGDB) environment in ESRI's ArcGIS. A major design-driving requirement for this datamodel is its extensibility and scalability for growing scientific as well as technical needs, e.g., the utilization of such a datamodel for surface mapping of different planetary objects as defined by their respective reference system and by using different instrument data. Furthermore, it is a major goal to construct a generic model which allows to perform combined geologic as well as geomorphologic mapping tasks making use of international standards without loss of information and by maintaining topologic integrity. An integration of such a datamodel within a geospatial DBMS context can practically be performed by individuals as well as groups without having to deal with the details of administrative tasks and data ingestion issues. Besides the actual mapping, key components of such a mapping datamodel deal with the organization and search for image-sensor data and previous mapping efforts, as well as the

  19. Torsional vibration signal analysis as a diagnostic tool for planetary gear fault detection

    Science.gov (United States)

    Xue, Song; Howard, Ian

    2018-02-01

    This paper aims to investigate the effectiveness of using the torsional vibration signal as a diagnostic tool for planetary gearbox faults detection. The traditional approach for condition monitoring of the planetary gear uses a stationary transducer mounted on the ring gear casing to measure all the vibration data when the planet gears pass by with the rotation of the carrier arm. However, the time variant vibration transfer paths between the stationary transducer and the rotating planet gear modulate the resultant vibration spectra and make it complex. Torsional vibration signals are theoretically free from this modulation effect and therefore, it is expected to be much easier and more effective to diagnose planetary gear faults using the fault diagnostic information extracted from the torsional vibration. In this paper, a 20 degree of freedom planetary gear lumped-parameter model was developed to obtain the gear dynamic response. In the model, the gear mesh stiffness variations are the main internal vibration generation mechanism and the finite element models were developed for calculation of the sun-planet and ring-planet gear mesh stiffnesses. Gear faults on different components were created in the finite element models to calculate the resultant gear mesh stiffnesses, which were incorporated into the planetary gear model later on to obtain the faulted vibration signal. Some advanced signal processing techniques were utilized to analyses the fault diagnostic results from the torsional vibration. It was found that the planetary gear torsional vibration not only successfully detected the gear fault, but also had the potential to indicate the location of the gear fault. As a result, the planetary gear torsional vibration can be considered an effective alternative approach for planetary gear condition monitoring.

  20. The four hundred years of planetary science since Galileo and Kepler.

    Science.gov (United States)

    Burns, Joseph A

    2010-07-29

    For 350 years after Galileo's discoveries, ground-based telescopes and theoretical modelling furnished everything we knew about the Sun's planetary retinue. Over the past five decades, however, spacecraft visits to many targets transformed these early notions, revealing the diversity of Solar System bodies and displaying active planetary processes at work. Violent events have punctuated the histories of many planets and satellites, changing them substantially since their birth. Contemporary knowledge has finally allowed testable models of the Solar System's origin to be developed and potential abodes for extraterrestrial life to be explored. Future planetary research should involve focused studies of selected targets, including exoplanets.

  1. Lunar and Planetary Science XXXII

    Science.gov (United States)

    2001-01-01

    This CD-ROM publication contains the extended abstracts that were accepted for presentation at the 32nd Lunar and Planetary Science Conference held at Houston, TX, March 12-16, 2001. The papers are presented in PDF format and are indexed by author, keyword, meteorite, program and samples for quick reference.

  2. Environmental microbiology as related to planetary quarantine. [synergetic effect of heat and radiation

    Science.gov (United States)

    Pflug, I. J.

    1973-01-01

    The mechanistic basis of the synergetic effect of combined heat and radiation on microbial destruction was analyzed and results show that radiation intensity, temperature, and relative humidity are the determining factors. Dry heat resistance evaluation for selected bacterial spore crops indicates that different strains of Bacillus stearothermophilus demonstrate marked differences in resistance. Preliminary work to determine the effects of storage time, suspending medium, storage temperature and spore crop cleaning procedures on dry heat survival characteristics of Bacillus subtilis var. Niger, and dry heat resistance of natural microflora in soil particles is also reported.

  3. Radiation hazards underestimated. Or?

    International Nuclear Information System (INIS)

    Breckow, J.

    2013-01-01

    Radiation protection claims that its regulations, policies and approaches are based on scientific evidence. If due to progress in science and technology new knowledge is added, it must be given to whether or not the existing radiation protection implementing is still appropriate or whether or not modifications need to be made. However, radiation protection is not just a matter of science. Continuity, consensus, accountability, public perception, communication and social acceptance play an important role in radiation protection as well. Thus, as new scientific evidence should be taken into account, not only the adequate implementation of radiation protection has to be discussed, but also their impact on the public perception and acceptance. It is one major challenge for all who are involved in radiation protection, to find an appropriate balance between these two aspects. (orig.)

  4. The study about planetary gearbox virtual prototyping with nonlinear gear contact characteristics

    International Nuclear Information System (INIS)

    Yin Huabing; Zhou Guangming

    2010-01-01

    The virtual prototypes of gear transmission system built in most multi-body dynamic software have difficulties in describing the gear mesh characteristics. The gear mesh contact is modelled as rigid contact and this is not accurate for the gear mesh contact, which is elastic or flexible. The gear contact formula used in the multi-body dynamic software does not reveal the gear contact nonlinear stiffness characteristic. The model built with gear meshing contact is difficult to solve because of its time-consuming algorithm. In the paper a new method is put forward to build the virtual prototype of planetary gearbox system according to the nonlinear mesh stiffness and mesh phase obtained through FEM models. This new FEM method of gear mesh stiffness calculation is much more accurate than the common formulas. The gear mesh nonlinear stiffness of sun gear- pinion and pinion-ring gear of all the planetary gear sets in gearbox are obtained through MATALB code, which is used to read and plot the analyzing result data. The gear mesh phase differences between different pinions with suns or rings of different planetary gear set can be also obtained. With all these data modelled in simulink (or other software) and integrated with the multi-body dynamic planetary gearbox model and the gear meshing contact problem in multi-body gear models is solved easily and accurately. The interfaces for gear mesh stiffness and mesh phases are designed for multi-body dynamic model and simulink. The nonlinear planetary gear set prototyping models are integrated to become the whole planetary gear box model and the whole vehicle system model built in multi-body dynamic software can be integrated to simulate different duty conditions. At last high speed input is put into the nonlinear planetary transmission model and the different duty cases are simulated. The dynamic characteristics of different parts are obtained. The dynamic characteristic comparison between nonlinear and linear models is made

  5. Detecting aromatic compounds on planetary surfaces using ultraviolet time-resolved fluorescence spectroscopy

    Science.gov (United States)

    Eshelman, E.; Daly, M. G.; Slater, G.; Cloutis, E.

    2018-02-01

    Many aromatic organic molecules exhibit strong and characteristic fluorescence when excited with ultraviolet radiation. As laser excitation in the ultraviolet generates both fluorescence and resonantly enhanced Raman scattering of aromatic vibrational modes, combined Raman and fluorescence instruments have been proposed to search for organic compounds on Mars. In this work the time-resolved fluorescence of a suite of 24 compounds composed of 2-5 ringed alternant, non-alternant, and heterocyclic PAHs was measured. Fluorescence instrumentation with similar specifications to a putative flight instrument was capable of observing the fluorescence decay of these compounds with a sub-ns resolution. Incorporating time-resolved capabilities was also found to increase the ability to discriminate between individual PAHs. Incorporating time-resolved fluorescence capabilities into an ultraviolet gated Raman system intended for a rover or lander can increase the ability to detect and characterize PAHs on planetary surfaces.

  6. A Methodology of Designing the Teeth Conjugation in a Planetary Roller Screw

    Directory of Open Access Journals (Sweden)

    Lisowski Filip

    2016-12-01

    Full Text Available The paper presents the methodology for designing the teeth conjunction of planetary gears in the planetary roller screw mechanism. A function of the planetary gears is to synchronize an operation of rollers in order to avoid axial displacements. A condition of the correct operation is no axial movement of rollers in relation to the nut. The planetary gears are integral parts of rollers and therefore an operation of the gear transmissions has a direct impact on cooperation of the screw, rollers and the nut. The proper design of gear engagements is essential for reducing slippage on surfaces of the cooperating threaded elements. For this purpose, in a designing method, both the limitations of operation and kinematic conditions of rollers’ operation have to be taken into account.

  7. Planetary Rings

    Science.gov (United States)

    Nicholson, P. D.

    2001-11-01

    A revolution in the studies in planetary rings studies occurred in the period 1977--1981, with the serendipitous discovery of the narrow, dark rings of Uranus, the first Voyager images of the tenuous jovian ring system, and the many spectacular images returned during the twin Voyager flybys of Saturn. In subsequent years, ground-based stellar occultations, HST observations, and the Voyager flybys of Uranus (1986) and Neptune (1989), as well as a handful of Galileo images, provided much additional information. Along with the completely unsuspected wealth of detail these observations revealed came an unwelcome problem: are the rings ancient or are we privileged to live at a special time in history? The answer to this still-vexing question may lie in the complex gravitational interactions recent studies have revealed between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto parent bodies. Perhaps most puzzling is Saturn's multi-stranded, clumpy F ring, which continues to defy a simple explanation 20 years after it was first glimpsed in grainy images taken by Pioneer 11. Voyager and HST images reveal a complex, probably chaotic, dynamical interaction between unseen parent bodies within this ring and its two shepherd satellites, Pandora and Prometheus. The work described here reflects contributions by Joe Burns, Jeff Cuzzi, Luke Dones, Dick French, Peter Goldreich, Colleen McGhee, Carolyn Porco, Mark Showalter, and Bruno Sicardy, as well as those of the author. This research has been supported by NASA's Planetary Geology and Geophysics program and the

  8. Planets around pulsars - Implications for planetary formation

    Science.gov (United States)

    Bodenheimer, Peter

    1993-01-01

    Data on planets around pulsars are summarized, and different models intended to explain the formation mechanism are described. Both theoretical and observational evidence suggest that very special circumstances are required for the formation of planetary systems around pulsars, namely, the prior presence of a millisecond pulsar with a close binary companion, probably a low mass main-sequence star. It is concluded that the discovery of two planets around PSR 1257+12 is important for better understanding the problems of dynamics and stellar evolution. The process of planetary formation should be learned through intensive studies of the properties of disks near young objects and application of techniques for detection of planets around main-sequence solar-type stars.

  9. Investments by NASA to build planetary protection capability

    Science.gov (United States)

    Buxbaum, Karen; Conley, Catharine; Lin, Ying; Hayati, Samad

    NASA continues to invest in capabilities that will enable or enhance planetary protection planning and implementation for future missions. These investments are critical to the Mars Exploration Program and will be increasingly important as missions are planned for exploration of the outer planets and their icy moons. Since the last COSPAR Congress, there has been an opportunity to respond to the advice of NRC-PREVCOM and the analysis of the MEPAG Special Regions Science Analysis Group. This stimulated research into such things as expanded bioburden reduction options, modern molecular assays and genetic inventory capability, and approaches to understand or avoid recontamination of spacecraft parts and samples. Within NASA, a portfolio of PP research efforts has been supported through the NASA Office of Planetary Protection, the Mars Technology Program, and the Mars Program Office. The investment strategy focuses on technology investments designed to enable future missions and reduce their costs. In this presentation we will provide an update on research and development supported by NASA to enhance planetary protection capability. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

  10. Planetary Taxonomy: Label Round Bodies "Worlds"

    Science.gov (United States)

    Margot, Jean-Luc; Levison, H. F.

    2009-05-01

    The classification of planetary bodies is as important to Astronomy as taxonomy is to other sciences. The etymological, historical, and IAU definitions of planet rely on a dynamical criterion, but some authors prefer a geophysical criterion based on "roundness". Although the former criterion is superior when it comes to classifying newly discovered objects, the conflict need not exist if we agree to identify the subset of "round" planetary objects as "worlds". This addition to the taxonomy would conveniently recognize that "round" objects such as Earth, Europa, Titan, Triton, and Pluto share some common planetary-type processes regardless of their distance from the host star. Some of these worlds are planets, others are not. Defining how round is round and handling the inevitable transition objects are non-trivial tasks. Because images at sufficient resolution are not available for the overwhelming majority of newly discovered objects, the degree of roundness is not a directly observable property and is inherently problematic as a basis for classification. We can tolerate some uncertainty in establishing the "world" status of a newly discovered object, and still establish its planet or satellite status with existing dynamical criteria. Because orbital parameters are directly observable, and because mass can often be measured either from orbital perturbations or from the presence of companions, the dynamics provide a robust and practical planet classification scheme. It may also be possible to determine which bodies are dynamically dominant from observations of the population magnitude/size distribution.

  11. ISO Spectroscopy of Proto-Planetary Nebulae

    Science.gov (United States)

    Hrivnak, Bruce J.

    2000-01-01

    features at 3.3, 6,2, 7.7, and 11.3 micron, which are commonly observed in planetary nebulae and HII regions, are also seen in these PPNs. However, their strengths relative to the continuum plateaus at 8 and 12 micron are weaker than in planetary nebulae. The 6.9 micron feature, seen almost exclusively in PPNs, is strong. The spectral energy distributions of these PPNs were fitted with a radiative-transfer model, taking into account the emission features at 21, 26, and 30 micron. A significant fraction of the total energy output is emitted in these features: as high as 20% in the 30 micron feature and 8% in the 21 micron feature. The fact that so much energy is carried in these features suggests that the material responsible for this feature must be made of abundant elements, and most likely involves carbon. The change in the in feature strengths from stronger aliphatic bonds in PPNs to stronger aromatic bonds in PNs suggests a chemical and physical evolution in the carbonaceous circumstellar dust during this transition time scale of a few thousand years.

  12. Determining Daily Radiation Interception in a Semiarid Inter ...

    African Journals Online (AJOL)

    ... in soil-plant-atmosphere continuum, as net radiation is a major part of the energy balance. ... Africa, where solar radiation is not a limiting factor for plant growth. The results suggested that ... Metrics Loading ... Metrics powered by PLOS ALM

  13. 3D Visualization for Planetary Missions

    Science.gov (United States)

    DeWolfe, A. W.; Larsen, K.; Brain, D.

    2018-04-01

    We have developed visualization tools for viewing planetary orbiters and science data in 3D for both Earth and Mars, using the Cesium Javascript library, allowing viewers to visualize the position and orientation of spacecraft and science data.

  14. Exploring the Largest Mass Fraction of the Solar System: the Case for Planetary Interiors

    Science.gov (United States)

    Danielson, L. R.; Draper, D.; Righter, K.; McCubbin, F.; Boyce, J.

    2017-01-01

    Why explore planetary interiors: The typical image that comes to mind for planetary science is that of a planet surface. And while surface data drive our exploration of evolved geologic processes, it is the interiors of planets that hold the key to planetary origins via accretionary and early differentiation processes. It is that initial setting of the bulk planet composition that sets the stage for all geologic processes that follow. But nearly all of the mass of planets is inaccessible to direct examination, making experimentation an absolute necessity for full planetary exploration.

  15. Institute of Geophysics, Planetary Physics, and Signatures

    Data.gov (United States)

    Federal Laboratory Consortium — The Institute of Geophysics, Planetary Physics, and Signatures at Los Alamos National Laboratory is committed to promoting and supporting high quality, cutting-edge...

  16. Cost estimation model for advanced planetary programs, fourth edition

    Science.gov (United States)

    Spadoni, D. J.

    1983-01-01

    The development of the planetary program cost model is discussed. The Model was updated to incorporate cost data from the most recent US planetary flight projects and extensively revised to more accurately capture the information in the historical cost data base. This data base is comprised of the historical cost data for 13 unmanned lunar and planetary flight programs. The revision was made with a two fold objective: to increase the flexibility of the model in its ability to deal with the broad scope of scenarios under consideration for future missions, and to maintain and possibly improve upon the confidence in the model's capabilities with an expected accuracy of 20%. The Model development included a labor/cost proxy analysis, selection of the functional forms of the estimating relationships, and test statistics. An analysis of the Model is discussed and two sample applications of the cost model are presented.

  17. Data Preservation and Curation for the Planetary Science Community

    Science.gov (United States)

    Hughes, J. S.; Crichton, D. J.; Joyner, R.; Hardman, S.; Rye, E.

    2013-12-01

    The Planetary Data System (PDS) has just released PDS4 Version 1.0, its next generation data standards for the planetary science archive. These data standards are the result of a multi-year effort to develop an information model based on accepted standards for data preservation, data curation, metadata management, and model development. The resulting information model is subsequently used to drive information system development from the generation of data standards documentation to the configuration of federated registries and search engines. This paper will provide an overview of the development of the PDS4 Information Model and focus on the application of the Open Archive Information System (OAIS) Reference Model - ISO 14721:2003, the Metadata Registry (MDR) Standard - ISO/IEC 11179, and the E-Business XML Standard to help ensure the long-term preservation and curation of planetary science data. Copyright 2013 California Institute of Technology Government sponsorship acknowledged

  18. HM Sagittae as a young planetary nebula

    International Nuclear Information System (INIS)

    Kwok, S.; Purton, C.R.

    1979-01-01

    HM Sagittae is suggested to be a very young planetary nebula recently transformed from a red-giant star through continuous mass loss. The observational data for HM Sge have been analyzed in terms of the interacting stellar wind model of planetary nebula formation. The model is in accord with virtually all the spectral data available--radio, optical, and infrared--as well as with the remarkable brightening of HM Sge observed in 1975. In particular, all three gaseous components predicted by the model are observed in the optical spectrum. The density in the newly formed shell is found to be at least 5 x 10 7 cm -3 , a value considerably higher than that found by the conventional analysis, which assumes a single-component homogeneous nebula. The radio spectrum is dominated by free-free emission from the remnant red-giant wind. The infrared spectrum suggests the presence of two dust components, one consisting of silicate grains left over from the red-giant stage and the other of grains newly formed after the 1975 brightening. The low observed shell mass is consistent with the interacting stellar wind model but is not consistent with the conventional sudden-ejection model of planetary nebula formation

  19. Degassing of reduced carbon from planetary basalts.

    Science.gov (United States)

    Wetzel, Diane T; Rutherford, Malcolm J; Jacobsen, Steven D; Hauri, Erik H; Saal, Alberto E

    2013-05-14

    Degassing of planetary interiors through surface volcanism plays an important role in the evolution of planetary bodies and atmospheres. On Earth, carbon dioxide and water are the primary volatile species in magmas. However, little is known about the speciation and degassing of carbon in magmas formed on other planets (i.e., Moon, Mars, Mercury), where the mantle oxidation state [oxygen fugacity (fO2)] is different from that of the Earth. Using experiments on a lunar basalt composition, we confirm that carbon dissolves as carbonate at an fO2 higher than -0.55 relative to the iron wustite oxygen buffer (IW-0.55), whereas at a lower fO2, we discover that carbon is present mainly as iron pentacarbonyl and in smaller amounts as methane in the melt. The transition of carbon speciation in mantle-derived melts at fO2 less than IW-0.55 is associated with a decrease in carbon solubility by a factor of 2. Thus, the fO2 controls carbon speciation and solubility in mantle-derived melts even more than previous data indicate, and the degassing of reduced carbon from Fe-rich basalts on planetary bodies would produce methane-bearing, CO-rich early atmospheres with a strong greenhouse potential.

  20. Earth as an Exoplanet: Lessons in Recognizing Planetary Habitability

    Science.gov (United States)

    Meadows, Victoria; Robinson, Tyler; Misra, Amit; Ennico, Kimberly; Sparks, William B.; Claire, Mark; Crisp, David; Schwieterman, Edward; Bussey, D. Ben J.; Breiner, Jonathan

    2015-01-01

    Earth will always be our best-studied example of a habitable world. While extrasolar planets are unlikely to look exactly like Earth, they may share key characteristics, such as oceans, clouds and surface inhomogeneity. Earth's globally-averaged characteristics can therefore help us to recognize planetary habitability in data-limited exoplanet observations. One of the most straightforward ways to detect habitability will be via detection of 'glint', specular reflectance from an ocean (Robinson et al., 2010). Other methods include undertaking a census of atmospheric greenhouse gases, or attempting to measure planetary surface temperature and pressure, to determine if liquid water would be feasible on the planetary surface. Here we present recent research on detecting planetary habitability, led by the NASA Astrobiology Institute's Virtual Planetary Laboratory Team. This work includes a collaboration with the NASA Lunar Science Institute on the detection of ocean glint and ozone absorption using Lunar Crater Observation and Sensing Satellite (LCROSS) Earth observations (Robinson et al., 2014). This data/model comparison provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths. We find that the VPL spectral Earth model is in excellent agreement with the LCROSS Earth data, and can be used to reliably predict Earth's appearance at a range of phases relevant to exoplanet observations. Determining atmospheric surface pressure and temperature directly for a potentially habitable planet will be challenging due to the lack of spatial-resolution, presence of clouds, and difficulty in spectrally detecting many bulk constituents of terrestrial atmospheres. Additionally, Rayleigh scattering can be masked by absorbing gases and absorption from the underlying surface. However, new techniques using molecular dimers of oxygen (Misra et al., 2014) and nitrogen

  1. Generalized detailed balance theory of solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kirchartz, Thomas

    2009-12-12

    The principle of detailed balance is the requirement that every microscopic process in a system must be in equilibrium with its inverse process, when the system itself is in thermodynamic equilibrium. This detailed balance principle has been of special importance for photovoltaics, since it allows the calculation of the limiting efficiency of a given solar cell by defining the only fundamental loss process as the radiative recombination of electron/hole pairs followed by the emission of a photon. In equilibrium, i.e. in the dark and without applied voltage, the absorbed and emitted photon flux must be equal due to detailed balance. This equality determines the radiative recombination from absorption and vice versa. While the classical theory of photovoltaic efficiency limits by Shockley and Queisser considers only one detailed balance pair, namely photogeneration and radiative recombination, the present work extends the detailed balance principle to any given process in the solar cell. Applying the detailed balance principle to the whole device leads to two major results, namely (i) a model that is compatible with the Shockley-Queisser efficiency limit for efficient particle transport, while still being able to describe non-ideal and non-linear solar cells, and (ii) an analytical relation between electroluminescent emission and photovoltaic action of a diode that is applied to a variety of different solar cells. This thesis presents several variations of a detailed balance model that are applicable to different types of solar cells. Any typical inorganic solar cell is a mainly bipolar device, meaning that the current is carried by electrons and holes. The detailed balance model for pn-type and pin-type bipolar solar cells is therefore the most basic incorporation of a detailed balance model. The only addition compared to the classical diode theory or compared to standard one-dimensional device simulators is the incorporation of photon recycling, making the model

  2. Planetary Science Exploration Through 2050: Strategic Gaps in Commercial and International Partnerships

    Science.gov (United States)

    Ghosh, A.

    2017-02-01

    Planetary science will see greater participation from the commercial sector and international space agencies. It is critical to understand how these entities can partner with NASA through 2050 and help realize NASA's goals in planetary science.

  3. Agriculture production as a major driver of the Earth system exceeding planetary boundaries

    Directory of Open Access Journals (Sweden)

    Bruce M. Campbell

    2017-12-01

    Full Text Available We explore the role of agriculture in destabilizing the Earth system at the planetary scale, through examining nine planetary boundaries, or "safe limits": land-system change, freshwater use, biogeochemical flows, biosphere integrity, climate change, ocean acidification, stratospheric ozone depletion, atmospheric aerosol loading, and introduction of novel entities. Two planetary boundaries have been fully transgressed, i.e., are at high risk, biosphere integrity and biogeochemical flows, and agriculture has been the major driver of the transgression. Three are in a zone of uncertainty i.e., at increasing risk, with agriculture the major driver of two of those, land-system change and freshwater use, and a significant contributor to the third, climate change. Agriculture is also a significant or major contributor to change for many of those planetary boundaries still in the safe zone. To reduce the role of agriculture in transgressing planetary boundaries, many interventions will be needed, including those in broader food systems.

  4. Energy and carbon balances in cheatgrass, an essay in autecology. [Shortwave radiation, radiowave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.

    1975-01-01

    An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)

  5. Quality assurance in radiation processing

    International Nuclear Information System (INIS)

    Noriah Mod Ali

    2002-01-01

    The growth of the radiation processing industries in Malaysia has presented the SSDL-MINT a new set of parameter for the Quality Assurance (QA) programs. The large massive doses of radiation required for commercial application of sterilization, cross-linking etc needs measurement method outside the scope of familiar radiation detection instruments. This requires establishment of proper calibration procedure and selection of appropriate transfer system/technique to assure adequate traceability to an international radiation standard. The benefit of accurate in-plant dosimetry for the operator, approving authority and purchaser are balanced against the extra dosimetric efforts required for good QA is presented. (Author)

  6. The Radiolytic Destruction of Glycine Diluted in H2O and CO2 Ice: Implications for Mars and Other Planetary Environments

    Science.gov (United States)

    Gerakines, Perry A.; Hudson, R. L.

    2013-10-01

    Future missions to Mars and other planetary surfaces will probe under the surfaces of these worlds for signs of organic chemistry. In previous studies we have shown that glycine and other amino acids have radiolytic destruction rates that depend on temperature and on dilution within an H2O ice matrix (Gerakines et al., 2012; Gerakines and Hudson 2013). In the new work presented here, we have examined the destruction of glycine diluted in CO2 ice at various concentrations and irradiated with protons at 0.8 MeV, typical of cosmic rays and solar energetic particles. Destruction rates for glycine were measured by infrared spectroscopy in situ, without removing or warming the ice samples. New results on the half life of glycine in solid CO2 will be compared to those found in H2O ice matrices. The survivability of glycine in icy planetary surfaces rich in H2O and CO2 ice will be discussed, and the implications for planetary science missions will be considered. References: Gerakines, P. A., Hudson, R. L., Moore, M. H., and Bell, J-L. (2012). In-situ Measurements of the Radiation Stability of Amino Acids at 15 - 140 K. Icarus, 220, 647-659. Gerakines, P. A. and Hudson, R. L. (2013). Glycine's Radiolytic Destruction in Ices: First in situ Laboratory Measurements for Mars. Astrobiology, 13, 647-655.

  7. Sealed Planetary Return Canister (SPRC), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample return missions have primary importance in future planetary missions. A basic requirement is that samples be returned in pristine, uncontaminated condition,...

  8. A Method Based on Multi-Sensor Data Fusion for Fault Detection of Planetary Gearboxes

    Directory of Open Access Journals (Sweden)

    Detong Kong

    2012-02-01

    Full Text Available Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that for systems as complex as planetary gearboxes, multiple sensors mounted on different locations provide complementary information on the health condition of the systems. On this basis, a fault detection method based on multi-sensor data fusion is introduced in this paper. In this method, two features developed for planetary gearboxes are used to characterize the gear health conditions, and an adaptive neuro-fuzzy inference system (ANFIS is utilized to fuse all features from different sensors. In order to demonstrate the effectiveness of the proposed method, experiments are carried out on a planetary gearbox test rig, on which multiple accelerometers are mounted for data collection. The comparisons between the proposed method and the methods based on individual sensors show that the former achieves much higher accuracies in detecting planetary gearbox faults.

  9. Health condition identification of multi-stage planetary gearboxes using a mRVM-based method

    Science.gov (United States)

    Lei, Yaguo; Liu, Zongyao; Wu, Xionghui; Li, Naipeng; Chen, Wu; Lin, Jing

    2015-08-01

    Multi-stage planetary gearboxes are widely applied in aerospace, automotive and heavy industries. Their key components, such as gears and bearings, can easily suffer from damage due to tough working environment. Health condition identification of planetary gearboxes aims to prevent accidents and save costs. This paper proposes a method based on multiclass relevance vector machine (mRVM) to identify health condition of multi-stage planetary gearboxes. In this method, a mRVM algorithm is adopted as a classifier, and two features, i.e. accumulative amplitudes of carrier orders (AACO) and energy ratio based on difference spectra (ERDS), are used as the input of the classifier to classify different health conditions of multi-stage planetary gearboxes. To test the proposed method, seven health conditions of a two-stage planetary gearbox are considered and vibration data is acquired from the planetary gearbox under different motor speeds and loading conditions. The results of three tests based on different data show that the proposed method obtains an improved identification performance and robustness compared with the existing method.

  10. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    Science.gov (United States)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  11. Planetary Sciences, Geodynamics, Impacts, Mass Extinctions, and Evolution: Developments and Interconnections

    Directory of Open Access Journals (Sweden)

    Jaime Urrutia-Fucugauchi

    2016-01-01

    Full Text Available Research frontiers in geophysics are being expanded, with development of new fields resulting from technological advances such as the Earth observation satellite network, global positioning system, high pressure-temperature physics, tomographic methods, and big data computing. Planetary missions and enhanced exoplanets detection capabilities, with discovery of a wide range of exoplanets and multiple systems, have renewed attention to models of planetary system formation and planet’s characteristics, Earth’s interior, and geodynamics, highlighting the need to better understand the Earth system, processes, and spatio-temporal scales. Here we review the emerging interconnections resulting from advances in planetary sciences, geodynamics, high pressure-temperature physics, meteorite impacts, and mass extinctions.

  12. The International Planetary Data Alliance (IPDA)

    Science.gov (United States)

    Stein, Thomas; Gopala Krishna, Barla; Crichton, Daniel J.

    2016-07-01

    The International Planetary Data Alliance (IPDA) is a close association of partners with the aim of improving the quality of planetary science data and services to the end users of space based instrumentation. The specific mission of the IPDA is to facilitate global access to, and exchange of, high quality scientific data products managed across international boundaries. Ensuring proper capture, accessibility and availability of the data is the task of the individual member space agencies. The IPDA is focused on developing an international standard that allows discovery, query, access, and usage of such data across international planetary data archive systems. While trends in other areas of space science are concentrating on the sharing of science data from diverse standards and collection methods, the IPDA concentrates on promoting governing data standards that drive common methods for collecting and describing planetary science data across the international community. This approach better supports the long term goal of easing data sharing across system and agency boundaries. An initial starting point for developing such a standard will be internationalization of NASA's Planetary Data System's (PDS) PDS4 standard. The IPDA was formed in 2006 with the purpose of adopting standards and developing collaborations across agencies to ensure data is captured in common formats. It has grown to a dozen member agencies represented by a number of different groups through the IPDA Steering Committee. Member agencies include: Armenian Astronomical Society, China National Space Agency (CNSA), European Space Agency (ESA), German Aerospace Center (DLR), Indian Space Research Organization (ISRO), Italian Space Agency (ASI), Japanese Aerospace Exploration Agency (JAXA), National Air and Space Administration (NASA), National Centre for Space Studies (CNES), Space Research Institute (IKI), UAE Space Agency, and UK Space Agency. The IPDA Steering Committee oversees the execution of

  13. Teaching, learning, and planetary exploration

    Science.gov (United States)

    Brown, Robert A.

    1992-01-01

    The progress accomplished in the first five months of the three-year grant period of Teaching, Learning, and Planetary Exploration is presented. The objectives of this project are to discover new education products and services based on space science, particularly planetary exploration. An Exploration in Education is the umbrella name for the education projects as they are seen by teachers and the interested public. As described in the proposal, our approach consists of: (1) increasing practical understanding of the potential role and capabilities of the research community to contribute to basic education using new discoveries; (2) developing an intellectual framework for these contributions by supplying criteria and templates for the teacher's stories; (3) attracting astronomers, engineers, and technical staff to the project and helping them form productive education partnerships for the future, (4) exploring relevant technologies and networks for authoring and communicating the teacher's stories; (5) enlisting the participation of potential user's of the teacher's stories in defining the products; (6) actually producing and delivering many educationally useful teacher's stories; and (7) reporting the pilot study results with critical evaluation. Technical progress was made by assembling our electronic publishing stations, designing electronic publications based on space science, and developing distribution approaches for electronic products. Progress was made addressing critical issues by developing policies and procedures for securing intellectual property rights and assembling a focus group of teachers to test our ideas and assure the quality of our products. The following useful materials are being produced: the TOPS report; three electronic 'PictureBooks'; one 'ElectronicArticle'; three 'ElectronicReports'; ten 'PrinterPosters'; and the 'FaxForum' with an initial complement of printed materials. We have coordinated with planetary scientists and astronomers

  14. Subsurface Prospecting by Planetary Drones, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed program innovates subsurface prospecting by planetary drones to seek a solution to the difficulty of robotic prospecting, sample acquisition, and sample...

  15. Get Involved in Planetary Discoveries through New Worlds, New Discoveries

    Science.gov (United States)

    Shupla, Christine; Shipp, S. S.; Halligan, E.; Dalton, H.; Boonstra, D.; Buxner, S.; SMD Planetary Forum, NASA

    2013-01-01

    "New Worlds, New Discoveries" is a synthesis of NASA’s 50-year exploration history which provides an integrated picture of our new understanding of our solar system. As NASA spacecraft head to and arrive at key locations in our solar system, "New Worlds, New Discoveries" provides an integrated picture of our new understanding of the solar system to educators and the general public! The site combines the amazing discoveries of past NASA planetary missions with the most recent findings of ongoing missions, and connects them to the related planetary science topics. "New Worlds, New Discoveries," which includes the "Year of the Solar System" and the ongoing celebration of the "50 Years of Exploration," includes 20 topics that share thematic solar system educational resources and activities, tied to the national science standards. This online site and ongoing event offers numerous opportunities for the science community - including researchers and education and public outreach professionals - to raise awareness, build excitement, and make connections with educators, students, and the public about planetary science. Visitors to the site will find valuable hands-on science activities, resources and educational materials, as well as the latest news, to engage audiences in planetary science topics and their related mission discoveries. The topics are tied to the big questions of planetary science: how did the Sun’s family of planets and bodies originate and how have they evolved? How did life begin and evolve on Earth, and has it evolved elsewhere in our solar system? Scientists and educators are encouraged to get involved either directly or by sharing "New Worlds, New Discoveries" and its resources with educators, by conducting presentations and events, sharing their resources and events to add to the site, and adding their own public events to the site’s event calendar! Visit to find quality resources and ideas. Connect with educators, students and the public to

  16. Hayes Receives 2012 Ronald Greeley Early Career Award in Planetary Science: Citation

    Science.gov (United States)

    Leshin, Laurie A.

    2013-10-01

    Alexander G. Hayes Jr. received the 2012 Ronald Greeley Early Career Award in Planetary Science at the 2012 AGU Fall Meeting, held 3-7 December in San Francisco, Calif. The award recognizes significant early-career contributions to planetary science.

  17. Planets and planetarians. A history of theories of the origin of planetary systems

    Energy Technology Data Exchange (ETDEWEB)

    Jaki, S L

    1978-01-01

    A critical review is presented of theories of the origin of planetary systems. The book deals chronologically with the subject from Greek times to the present. The last of the eight chapters covers the post-war period. Particular attention is paid to theories of the origin of our own planetary system and to the degree of frequency of planetary systems (in particular, the frequency of planets carrying life in some form) in the universe.

  18. Planetary Surface-Atmosphere Interactions

    Science.gov (United States)

    Merrison, J. P.; Bak, E.; Finster, K.; Gunnlaugsson, H. P.; Holstein-Rathlou, C.; Knak Jensen, S.; Nørnberg, P.

    2013-09-01

    Planetary bodies having an accessible solid surface and significant atmosphere, such as Earth, Mars, Venus, Titan, share common phenomenology. Specifically wind induced transport of surface materials, subsequent erosion, the generation and transport of solid aerosols which leads both to chemical and electrostatic interaction with the atmosphere. How these processes affect the evolution of the atmosphere and surface will be discussed in the context of general planetology and the latest laboratory studies will be presented.

  19. Evolution of space drones for planetary exploration: A review

    Science.gov (United States)

    Hassanalian, M.; Rice, D.; Abdelkefi, A.

    2018-02-01

    In the past decade, there has been a tendency to design and fabricate drones which can perform planetary exploration. Generally, there are various ways to study space objects, such as the application of telescopes and satellites, launching robots and rovers, and sending astronauts to the targeted solar bodies. However, due to the advantages of drones compared to other approaches in planetary exploration, ample research has been carried out by different space agencies in the world, including NASA to apply drones in other solar bodies. In this review paper, several studies which have been performed on space drones for planetary exploration are consolidated and discussed. Design and fabrication challenges of space drones, existing methods for their flight tests, different methods for deployment and planet entry, and various navigation and control approaches are reviewed and discussed elaborately. Limitations of applying space drones, proposed solutions for future space drones, and recommendations are also presented and discussed.

  20. First characterization and comparison of TEB model simulations with in situ measurements regarding radiation balance in a single urban canyon at the BOKU site (Vienna)

    Science.gov (United States)

    Oswald, Sandro; Trimmel, Heidelinde; Revesz, Michael; Nadeem, Imran; Masson, Valéry; Weihs, Philipp

    2017-04-01

    According to the World Health Organization more than half of the world population lives in a city since 2010. Predictions foresee that by 2030 six out of ten people will live in an urban area. As a result, many cities are expanding in size. Almost 10% of all urban dwellers live in megacities (defined according to UN HABITAT as a city with a population of more than 10 million). There are several effects in cities which strongly influence human health. Visible influences like the severe emissions of air pollutants by industry and traffic (e.g. Mayer H., 1999, Grimmond et al., 2010) are obvious to people but thermal stress in urban areas is only recently recognized for its strong devastating effect on human health. As a consequence, the urban environment virtually influences all weather parameters that have an impact on human comfort and thermal stress. Within this study, we investigate effects of city growth and the development of outlying districts on the local climate of Vienna. We focus particularly on the influence of urban heat island and consequent the risk for heat related illnesses or thermal stress for people. To quantify radiation balance and other important meteorological factors, we performed an extensive field campaign with three types of net radiometer in three different heights at BOKU site in August 2016. The first results indicated a strong correlation (ρ=0.96) between the Town Energy Balance (TEB) model and the measurements of the top net radiometer regarding radiation balance at roof level, meanwhile the TEB results are slightly underestimated. Further check if the measurements are reasonable, a comparison of the input values (global and direct solar radiation) for the TEB simulation with Secondary Standard measurements of ARAD site Wien Hohe Warte shows a deviation under 2% concerning interquartile range on clear sky days. The next steps will enclose TEB simulations, coupled with the mesoscale Weather Research and Forecasting (WRF) model, for

  1. Arc tracking energy balance for copper and aluminum aeronautic cables

    International Nuclear Information System (INIS)

    André, T; Valensi, F; Teulet, P; Cressault, Y; Zink, T; Caussé, R

    2017-01-01

    Arc tracking tests have been carried out between two voluntarily damaged aeronautic cables. Copper or aluminum conductors have been exposed to short circuits under alternating current. Various data have been recorded (arc voltage and current, radiated power and ablated mass), enabling to determine a power balance, in which every contribution is estimated. The total power is mainly transferred to the cables (between 50 and 65%, depending on the current and the cable type), and causes the melting and partial vaporization of the metallic core and insulating material, or is conducted or radiated. The other part is deposited into the arc column, being either radiated, convected or conducted. (paper)

  2. Heat balance characteristics and water use efficiency of soybean community

    International Nuclear Information System (INIS)

    Lee, Y.S.; Im, J.N.

    1990-01-01

    A field experiment was conducted to study seasonal evapotranspiration above soybean canopy and its relationship with dry matter production by the Bowen ratio-energy balance method. The soybean ''Paldalkong'' was sown with the space of 40 * 10 cm at Suwon on May 27, 1988. The daily net radiation ranged from 59 to 76 percents of the total shortwave radiation under cloudless conditions, which was lower than cloud overcast condition with record 63 to 83 percents. The latent heat flux under overcast condition was sometimes larger than the sum of net radiation, implying transportation of energy by advection of ambient air

  3. Virtual Planetary Space Weather Services offered by the Europlanet H2020 Research Infrastructure

    Science.gov (United States)

    André, N.; Grande, M.; Achilleos, N.; Barthélémy, M.; Bouchemit, M.; Benson, K.; Blelly, P.-L.; Budnik, E.; Caussarieu, S.; Cecconi, B.; Cook, T.; Génot, V.; Guio, P.; Goutenoir, A.; Grison, B.; Hueso, R.; Indurain, M.; Jones, G. H.; Lilensten, J.; Marchaudon, A.; Matthiä, D.; Opitz, A.; Rouillard, A.; Stanislawska, I.; Soucek, J.; Tao, C.; Tomasik, L.; Vaubaillon, J.

    2018-01-01

    Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI) will include an entirely new Virtual Access Service, "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. PSWS will make twelve new services accessible to the research community, space agencies, and industrial partners planning for space missions. These services will in particular be dedicated to the following key planetary environments: Mars (in support of the NASA MAVEN and European Space Agency (ESA) Mars Express and ExoMars missions), comets (building on the outstanding success of the ESA Rosetta mission), and outer planets (in preparation for the ESA JUpiter ICy moon Explorer mission), and one of these services will aim at predicting and detecting planetary events like meteor showers and impacts in the Solar System. This will give the European planetary science community new methods, interfaces, functionalities and/or plugins dedicated to planetary space weather as well as to space situational awareness in the tools and models available within the partner institutes. A variety of tools (in the form of web applications, standalone software, or numerical models in various degrees of implementation) are available for tracing propagation of planetary and/or solar events through the Solar System and modelling the response of the planetary environment (surfaces, atmospheres, ionospheres, and magnetospheres) to those events. But these tools were not originally designed for planetary event prediction and space weather applications. PSWS will provide the additional research and tailoring required to apply them for these purposes. PSWS will be to review, test, improve and adapt methods and tools available within the partner institutes in order to make prototype planetary event and space weather services operational in Europe at the end

  4. A phase angle based diagnostic scheme to planetary gear faults diagnostics under non-stationary operational conditions

    Science.gov (United States)

    Feng, Ke; Wang, Kesheng; Ni, Qing; Zuo, Ming J.; Wei, Dongdong

    2017-11-01

    Planetary gearbox is a critical component for rotating machinery. It is widely used in wind turbines, aerospace and transmission systems in heavy industry. Thus, it is important to monitor planetary gearboxes, especially for fault diagnostics, during its operational conditions. However, in practice, operational conditions of planetary gearbox are often characterized by variations of rotational speeds and loads, which may bring difficulties for fault diagnosis through the measured vibrations. In this paper, phase angle data extracted from measured planetary gearbox vibrations is used for fault detection under non-stationary operational conditions. Together with sample entropy, fault diagnosis on planetary gearbox is implemented. The proposed scheme is explained and demonstrated in both simulation and experimental studies. The scheme proves to be effective and features advantages on fault diagnosis of planetary gearboxes under non-stationary operational conditions.

  5. Generic and scientific constraints involving geoethics and geoeducation in planetary geosciences

    Science.gov (United States)

    Martínez-Frías, Jesús

    2013-04-01

    Geoscience education is a key factor in the academic, scientific and professional progress of any modern society. Geoethics is an interdisciplinary field, which involves Earth and Planetary Sciences as well as applied ethics, regarding the study of the abiotic world. These coss-cutting interactions linking scientific, societal and cultural aspects, consider our planet, in its modern approach, as a system and as a model. This new perspective is extremely important in the context of geoducation in planetary geosciences. In addition, Earth, our home planet, is the only planet in our solar system known to harbor life. This also makes it crucial to develop any scientific strategy and methodological technique (e.g. Raman spectroscopy) of searching for extraterrestrial life. In this context, it has been recently proposed [1-3] that the incorporation of the geoethical and geodiversity issues in planetary geology and astrobiology studies would enrich their methodological and conceptual character (mainly but not only in relation to planetary protection). Modern geoscience education must take into account that, in order to understand the origin and evolution of our planet, we need to be aware that the Earth is open to space, and that the study of meteorites, asteroids, the Moon and Mars is also essential for this purpose (Earth analogs are also unique sites to define planetary guidelines). Generic and scientific constraints involving geoethics and geoeducation should be incorporated into the teaching of all fundamental knowledge and skills for students and teachers. References: [1] Martinez-Frias, J. et al. (2009) 9th European Workshop on Astrobiology, EANA 09, 12-14 October 2009, Brussels, Belgiam. [2] Martinez-Frias, J., et al. (2010) 38th COSPAR Scientific Assembly. Protecting the Lunar and Martian Environments for Scientific Research, Bremen, Germany, 18-25 July. [3] Walsh et al. (2012) 43rd Lunar and Planetary Science Conference, 1910.pdf

  6. Planets and planetarians. A history of theories of the origin of planetary systems

    International Nuclear Information System (INIS)

    Jaki, S.L.

    1978-01-01

    A critical review is presented of theories of the origin of planetary systems. The book deals chronologically with the subject from Greek times to the present. The last of the eight chapters covers the post-war period. Particular attention is paid to theories of the origin of our own planetary system and to the degree of frequency of planetary systems (in particular, the frequency of planets carrying life in some form) in the universe. (U.K.)

  7. 78 FR 64253 - NASA Advisory Council; Science Committee; Planetary Protection Subcommittee; Meeting

    Science.gov (United States)

    2013-10-28

    ...; Issues and Status --Planetary Protection for Cached Mars Samples --Planetary Science Update --Mars... later than the close of business November 5, 2013. Foreign Nationals must provide following information: full name, gender, date/place of birth, citizenship, home address, visa information (number, type...

  8. Modeling Radiative Heat Transfer and Turbulence-Radiation Interactions in Engines

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Chandan [Pennsylvania State Univ., University Park, PA (United States); Sircar, Arpan [Pennsylvania State Univ., University Park, PA (United States); Ferreyro-Fernandez, Sebastian [Pennsylvania State Univ., University Park, PA (United States); Imren, Abdurrahman [Pennsylvania State Univ., University Park, PA (United States); Haworth, Daniel C [Pennsylvania State Univ., University Park, PA (United States); Roy, Somesh P [Marquette University (United States); Ge, Wenjun [University of California Merced (United States); Modest, Michael F [University of California Merced (United States)

    2017-04-26

    Detailed radiation modelling in piston engines has received relatively little attention to date. Recently, it is being revisited in light of current trends towards higher operating pressures and higher levels of exhaust-gas recirculation, both of which enhance molecular gas radiation. Advanced high-efficiency engines also are expected to function closer to the limits of stable operation, where even small perturbations to the energy balance can have a large influence on system behavior. Here several different spectral radiation property models and radiative transfer equation (RTE) solvers have been implemented in an OpenFOAM-based engine CFD code, and simulations have been performed for a full-load (peak pressure ~200 bar) heavy-duty diesel engine. Differences in computed temperature fields, NO and soot levels, and wall heat transfer rates are shown for different combinations of spectral models and RTE solvers. The relative importance of molecular gas radiation versus soot radiation is examined. And the influence of turbulence-radiation interactions is determined by comparing results obtained using local mean values of composition and temperature to compute radiative emission and absorption with those obtained using a particle-based transported probability density function method.

  9. Automated Planning and Scheduling for Planetary Rover Distributed Operations

    Science.gov (United States)

    Backes, Paul G.; Rabideau, Gregg; Tso, Kam S.; Chien, Steve

    1999-01-01

    Automated planning and Scheduling, including automated path planning, has been integrated with an Internet-based distributed operations system for planetary rover operations. The resulting prototype system enables faster generation of valid rover command sequences by a distributed planetary rover operations team. The Web Interface for Telescience (WITS) provides Internet-based distributed collaboration, the Automated Scheduling and Planning Environment (ASPEN) provides automated planning and scheduling, and an automated path planner provided path planning. The system was demonstrated on the Rocky 7 research rover at JPL.

  10. Radiation loss driven instabilities in laser heated plasmas

    International Nuclear Information System (INIS)

    Evans, R.G.

    1985-01-01

    Any plasma in which a significant part of the power balance is due to optically thin radiative losses may be subject to a radiation cooling instability. A simple analytical model gives the dispersion relation for the instability and inclusion of a realistic radiation loss term in a two dimensional hydrodynamic simulation shows that ''jet'' like features form in moderate to high Z plasmas

  11. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2008

    Energy Technology Data Exchange (ETDEWEB)

    LR Roeder

    2008-12-01

    The Importance of Clouds and Radiation for Climate Change: The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols, can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To reduce these scientific uncertainties, the ARM Program uses a unique twopronged approach: • The ARM Climate Research Facility, a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes; and • The ARM Science Program, focused on the analysis of ACRF and other data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report provides an overview of each of these components and a sample of achievements for each in fiscal year (FY) 2008.

  12. Bringing Terramechanics to bear on Planetary Rover Design

    Science.gov (United States)

    Richter, L.

    2007-08-01

    Thus far, planetary rovers have been successfully operated on the Earth's moon and on Mars. In particular, the two NASA Mars Exploration Rovers (MERs) ,Spirit' and ,Opportunity' are still in sustained daily operations at two sites on Mars more than 3 years after landing there. Currently, several new planetary rover missions are in development targeting Mars (the US Mars Science Lab vehicle for launch in 2009 and ESA's ExoMars rover for launch in 2013), with lunar rover missions under study by China and Japan for launches around 2012. Moreover, the US Constellation program is preparing pre-development of lunar rovers for initially unmanned and, subsequently, human missions to the Moon with a corresponding team dedicated to mobility system development having been set up at the NASA Glenn Research Center. Given this dynamic environment, it was found timely to establish an expert group on off-the-road mobility as relevant for robotic vehicles that would involve individuals representing the various on-going efforts on the different continents. This was realized through the International Society of Terrain-Vehicle Systems (ISTVS), a research organisation devoted to terramechanics and to the ,science' of off-the-road vehicle development which as a result is just now establishing a Technical Group on Terrestrial and Planetary Rovers. Members represent space-related as well as military research institutes and universities from the US, Germany, Italy, and Japan. The group's charter for 2007 is to define its objectives, functions, organizational structure and recommended research objectives to support planetary rover design and development. Expected areas of activity of the ISTVS-sponsored group include: the problem of terrain specification for planetary rovers; identification of limitations in modelling of rover mobility; a survey of existing rover mobility testbeds; the consolidation of mobility predictive models and their state of validation; sensing and real

  13. PSUP: A Planetary SUrface Portal

    Science.gov (United States)

    Poulet, F.; Quantin-Nataf, C.; Ballans, H.; Dassas, K.; Audouard, J.; Carter, J.; Gondet, B.; Lozac'h, L.; Malapert, J.-C.; Marmo, C.; Riu, L.; Séjourné, A.

    2018-01-01

    The large size and complexity of planetary data acquired by spacecraft during the last two decades create a demand within the planetary community for access to the archives of raw and high level data and for the tools necessary to analyze these data. Among the different targets of the Solar System, Mars is unique as the combined datasets from the Viking, Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter missions provide a tremendous wealth of information that can be used to study the surface of Mars. The number and the size of the datasets require an information system to process, manage and distribute data. The Observatories of Paris Sud (OSUPS) and Lyon (OSUL) have developed a portal, called PSUP (Planetary SUrface Portal), for providing users with efficient and easy access to data products dedicated to the Martian surface. The objectives of the portal are: 1) to allow processing and downloading of data via a specific application called MarsSI (Martian surface data processing Information System); 2) to provide the visualization and merging of high level (image, spectral, and topographic) products and catalogs via a web-based user interface (MarsVisu), and 3) to distribute some of these specific high level data with an emphasis on products issued by the science teams of OSUPS and OSUL. As the MarsSI service is extensively described in a companion paper (Quantin-Nataf et al., companion paper, submitted to this special issue), the present paper focus on the general architecture and the functionalities of the web-based user interface MarsVisu. This service provides access to many data products for Mars: albedo, mineral and thermal inertia global maps from spectrometers; mosaics from imagers; image footprints and rasters from the MarsSI tool; high level specific products (defined as catalogs or vectors). MarsVisu can be used to quickly assess the visualized processed data and maps as well as identify areas that have not been mapped yet

  14. High pressure studies of planetary matter

    International Nuclear Information System (INIS)

    Ross, M.

    1989-06-01

    Those materials which are of greatest interest to the physics of the deep planetary interiors are Fe, H 2 , He and the Ices. These are sufficiently diverse and intensively studied to offer an overview of present day high pressure research. 13 refs., 1 fig

  15. 2010 Gordon Research Conference On Radiation Chemistry

    International Nuclear Information System (INIS)

    Orlando, Thomas

    2010-01-01

    The 2010 Gordon Conference on Radiation Chemistry will present cutting edge research regarding the study of radiation-induced chemical transformations. Radiation Chemistry or 'high energy' chemistry is primarily initiated by ionizing radiation: i.e. photons or particles with energy sufficient to create conduction band electrons and 'holes', excitons, ionic and neutral free radicals, highly excited states, and solvated electrons. These transients often interact or 'react' to form products vastly different than those produced under thermal equilibrium conditions. The non-equilibrium, non-thermal conditions driving radiation chemistry exist in plasmas, star-forming regions, the outer solar system, nuclear reactors, nuclear waste repositories, radiation-based medical/clinical treatment centers and in radiation/materials processing facilities. The 2010 conference has a strong interdisciplinary flavor with focus areas spanning (1) the fundamental physics and chemistry involved in ultrafast (atto/femtosecond) energy deposition events, (2) radiation-induced processes in biology (particularly spatially resolved studies), (3) radiation-induced modification of materials at the nanoscale and cosmic ray/x-ray mediated processes in planetary science/astrochemistry. While the conference concentrates on fundamental science, topical applied areas covered will also include nuclear power, materials/polymer processing, and clinical/radiation treatment in medicine. The Conference will bring together investigators at the forefront of their field, and will provide opportunities for junior scientists and graduate students to present work in poster format or as contributors to the Young Investigator session. The program and format provides excellent avenues to promote cross-disciplinary collaborations.

  16. Planetary nebulae and Wolf-Rayet stars in the galactic-centre field

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D A [Anglo-Australian Observatory, Epping (Australia)

    1979-06-01

    A UK Schmidt objective-prism plate of the Galactic-centre field has been examined. Of the 74 objects in the field which have been catalogued as planetary nebulae, only half appear correctly classified; the others include Be stars, symbiotic stars, and stars without emission lines. A further 19 planetary nebulae and two Wolf-Rayet stars have been discovered.

  17. Implementation of cartographic symbols for planetary mapping in geographic information systems

    Science.gov (United States)

    Nass, A.; van Gasselt, S.; Jaumann, R.; Asche, H.

    2011-09-01

    The steadily growing international interest in the exploration of planets in our Solar System and many advances in the development of space-sensor technology have led to the launch of a multitude of planetary missions to Mercury, Venus, the Earth's moon, Mars and various Outer-Solar System objects, such as the Jovian and Saturnian satellites. Camera instruments carried along on these missions image surfaces in different wavelength ranges and under different viewing angles, permitting additional data to be derived, such as spectral data or digital terrain models. Such data enable researchers to explore and investigate the development of planetary surfaces by analyzing and interpreting the inventory of surface units and structures. Results of such work are commonly abstracted and represented in thematic, mostly geological and geomorphological, maps. In order to facilitate efficient collaboration among different planetary research disciplines, mapping results need to be prepared, described, managed, archived, and visualized in a uniform way. These tasks have been increasingly carried out by means of computer-based geographic information systems (GIS or GI systems) which have come to be widely employed in the field of planetary research since the last two decades. In this paper we focus on the simplification of mapping processes, putting specific emphasis on a cartographically correct visualization of planetary mapping data using GIS-based environments. We present and discuss the implementation of a set of standardized cartographic symbols for planetary mapping based on the Digital Cartographic Standard for Geologic Map Symbolization as prepared by the United States Geological Survey (USGS) for the Federal Geographic Data Committee (FGDC). Furthermore, we discuss various options to integrate this symbol catalog into generic GI systems, and more specifically into the Environmental Systems Research Institute's (ESRI) ArcGIS environment, and focus on requirements for

  18. The European standard on planetary protection requirements.

    Science.gov (United States)

    Debus, André

    2006-01-01

    Since the beginning of solar system exploration, numerous spacecrafts have been sent towards others worlds, and one of the main goals of such missions is the search for extraterrestrial forms of life. It is known that, under certain conditions, some terrestrial entities are able to survive during cruises in space and that they may contaminate other planets (forward contamination). At another level, possible extraterrestrial life forms are unknown and their ability to contaminate the Earth's biosphere (back contamination) in the frame of sample return missions cannot be excluded. Article IX of the Outer Space Treaty (London/Washington, January 27, 1967) requires the preservation of planets and the Earth from contamination. All nations taking part in this Treaty must prevent forward and back contamination during missions exploring our solar system. Consequently, the United Nations (UN-COPUOS) has delegated COSPAR (Committee of Space Research) to take charge of planetary protection and, at present, all space-faring nations must comply with COSPAR policy and consequently with COSPAR planetary protection recommendations. Starting from these recommendations and the "CNES Planetary Protection Standard" document, a working group has been set up in the framework of the "European Cooperation for Space Standardization" (ECSS) to establish the main specifications for preventing cross-contamination between target bodies within the solar system and the Earth-moon system.

  19. A Planetary Park system for the Moon and beyond

    Science.gov (United States)

    Cockell, Charles; Horneck, Gerda

    Deutschland International space exploration programs foresee the establishment of human settlements on the Moon and on Mars within the next decades, following a series of robotic precursor missions. These increasing robotic visits and eventual human exploration and settlements may have an environmental impact on scientifically important sites and sites of natural beauty in the form of contamination with microorganisms and spacecraft parts, or even pollution as a consequence of in situ resource use. This concern has already been reflected in the Moon Treaty, "The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies" of the United Nations, which follows the Outer Space Treaty of the UN. However, so far, the Moon Treaty has not been ratified by any nation which engages in human space programs or has plans to do so. Planetary protection guidelines as formulated by the Committee on Space Research (COSPAR) are based on the Outer Space Treaty and follow the objectives: (i) to prevent contamination by terrestrial microorganisms if this might jeopardize scientific investi-gations of possible extraterrestrial life forms, and (ii) to protect the Earth from the potential hazard posed by extraterrestrial material brought back to the Earth. As a consequence, they group exploratory missions according to the type of mission and target body in five different categories, requesting specific means of cleaning and sterilization. However, the protection of extraterrestrial environments might also encompass ethical and other non-instrumental reasons. In order to allow intense scientific research and exploitation, and on the other hand to preserve regions of the Moon for research and use by future generations, we proposed the introduction of a planetary (or lunar) park system, which would protect areas of scientific, historic and intrinsic value under a common scheme. A similar placePlaceNamePlanetary PlaceTypePark system could be established on Mars well

  20. Women in Planetary Science: Career Resources and e-Mentoring on Blogs, Twitter, Facebook, Google+, and Pinterest

    Science.gov (United States)

    Niebur, S. M.; Singer, K.; Gardner-Vandy, K.

    2012-08-01

    Fifty-one interviews with women in planetary science are now available as an e-mentoring and teaching resource on WomeninPlanetaryScience.com. Each scientist was nominated and interviewed by a fellow member of the planetary science community, and each gladly shared her advice for advancement in the field. Women in Planetary Science was founded in 2008 to connect communities of current and prospective scientists, to promote proposal and award opportunities, and to stimulate discussion in the planetary science community at large. Regular articles, or posts, by nearly a dozen collaborators highlight a range of current issues for women in this field. These articles are promoted by collaborators on Twitter, Facebook, and Google+ and shared again by the collaborators' contacts, reaching a significantly wider audience. The group's latest project, on Pinterest, is a crowd-sourced photo gallery of more than 350 inspiring women in planetary science; each photo links to the scientist's CV. The interviews, the essays, and the photo gallery are available online as resources for prospective scientists, planetary scientists, parents, and educators.

  1. The effect of roll with passive segment on the planetary rolling process

    Directory of Open Access Journals (Sweden)

    Qing-Ling Zeng

    2015-03-01

    Full Text Available In three-roll planetary rolling process, there is secondary torsion phenomenon that may lead to rolling instability. This article proposed a new idea to alleviate the secondary torsion phenomenon by dividing the secondary torsion segment out of the roll as an independent and passive one. To study the performance of the roll with passive segment, the three-dimensional finite element models of planetary rolling process using actual roll or new roll with passive segment involving elastic–plastic and thermal–mechanical coupling were established by the software ABAQUS/Explicit, and a series of analysis had been done successfully. The rolling temperature and rolling force of planetary mill were in good agreement with the measured results, which indicated that the finite element method would supply important reference merit for three-dimensional thermo-mechanical simulation of the three-roll planetary rolling process. Comparing the simulation results of the two models, the results indicated that the change in the roll structure had just a little influence on the metal deformation, temperature, and rolling force, but it lessened the secondary torsion deformation effectively and improved the outside roundness of the rolled tube slightly. The research provided a new idea for the roll design of three-roll planetary mill (PSW.

  2. PROTECTION FROM COSMIC RADIATION IN LONG-TERM MANNED SPACEFLIGHTS

    Directory of Open Access Journals (Sweden)

    Marco Durante

    2012-06-01

    Full Text Available Current space programs are shifting toward planetary exploration, and in particular towards human missions to the moon and Mars. Space radiation, comprised of energetic protons and heavy nuclei, has been shown to produce distinct biological damage compared to radiation on Earth, leading to large uncertainties in the projection of health risks. Even if uncertainties in risk assessment will be reduced in the next few years, there is little doubt that appropriate countermeasures have to be taken to reduce the exposure or the biological damage produced by cosmic radiation. In addition, it is necessary to provide effective countermeasures against solar particle events, which can produce acute effects, even life threatening, for inadequately protected crews. Unfortunately, passive (bulk shielding is currently unable to provide adequate protection, because cosmic rays have very high energy and nuclear fragmentation in the absorbers produce light fragments. Material science could provide new materials with better shielding properties for space radiation. Active (magnetic shielding could be an interesting alternative, pending technical improvements.

  3. NASA Lunar and Planetary Mapping and Modeling

    Science.gov (United States)

    Day, B. H.; Law, E.

    2016-12-01

    NASA's Lunar and Planetary Mapping and Modeling Portals provide web-based suites of interactive visualization and analysis tools to enable mission planners, planetary scientists, students, and the general public to access mapped lunar data products from past and current missions for the Moon, Mars, and Vesta. New portals for additional planetary bodies are being planned. This presentation will recap significant enhancements to these toolsets during the past year and look forward to the results of the exciting work currently being undertaken. Additional data products and tools continue to be added to the Lunar Mapping and Modeling Portal (LMMP). These include both generalized products as well as polar data products specifically targeting potential sites for the Resource Prospector mission. Current development work on LMMP also includes facilitating mission planning and data management for lunar CubeSat missions, and working with the NASA Astromaterials Acquisition and Curation Office's Lunar Apollo Sample database in order to help better visualize the geographic contexts from which samples were retrieved. A new user interface provides, among other improvements, significantly enhanced 3D visualizations and navigation. Mars Trek, the project's Mars portal, has now been assigned by NASA's Planetary Science Division to support site selection and analysis for the Mars 2020 Rover mission as well as for the Mars Human Landing Exploration Zone Sites. This effort is concentrating on enhancing Mars Trek with data products and analysis tools specifically requested by the proposing teams for the various sites. Also being given very high priority by NASA Headquarters is Mars Trek's use as a means to directly involve the public in these upcoming missions, letting them explore the areas the agency is focusing upon, understand what makes these sites so fascinating, follow the selection process, and get caught up in the excitement of exploring Mars. The portals also serve as

  4. Planetary tides during the Maunder sunspot minimum

    International Nuclear Information System (INIS)

    Smythe, C.M.; Eddy, J.A.

    1977-01-01

    Sun-centered planetary conjunctions and tidal potentials are here constructed for the AD1645 to 1715 period of sunspot absence, referred to as the 'Maunder Minimum'. These are found to be effectively indistinguishable from patterns of conjunctions and power spectra of tidal potential in the present era of a well established 11 year sunspot cycle. This places a new and difficult restraint on any tidal theory of sunspot formation. Problems arise in any direct gravitational theory due to the apparently insufficient forces and tidal heights involved. Proponents of the tidal hypothesis usually revert to trigger mechanisms, which are difficult to criticise or test by observation. Any tidal theory rests on the evidence of continued sunspot periodicity and the substantiation of a prolonged period of solar anomaly in the historical past. The 'Maunder Minimum' was the most drastic change in the behaviour of solar activity in the last 300 years; sunspots virtually disappeared for a 70 year period and the 11 year cycle was probably absent. During that time, however, the nine planets were all in their orbits, and planetary conjunctions and tidal potentials were indistinguishable from those of the present era, in which the 11 year cycle is well established. This provides good evidence against the tidal theory. The pattern of planetary tidal forces during the Maunder Minimum was reconstructed to investigate the possibility that the multiple planet forces somehow fortuitously cancelled at the time, that is that the positions of the slower moving planets in the 17th and early 18th centuries were such that conjunctions and tidal potentials were at the time reduced in number and force. There was no striking dissimilarity between the time of the Maunder Minimum and any period investigated. The failure of planetary conjunction patterns to reflect the drastic drop in sunspots during the Maunder Minimum casts doubt on the tidal theory of solar activity, but a more quantitative test

  5. Efficient Radiation Simulation in Complex Geometries with Applications to Planetary Entry, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA aerocapture missions require an accurate evaluation of radiative thermal transport in order to simulate the aerothermal environment around space vehicles....

  6. Numerical models of planetary dynamos

    International Nuclear Information System (INIS)

    Glatzmaier, G.A.; Roberts, P.H.

    1992-01-01

    We describe a nonlinear, axisymmetric, spherical-shell model of planetary dynamos. This intermediate-type dynamo model requires a prescribed helicity field (the alpha effect) and a prescribed buoyancy force or thermal wind (the omega effect) and solves for the axisymmetric time-dependent magnetic and velocity fields. Three very different time dependent solutions are obtained from different prescribed sets of alpha and omega fields

  7. Using Vulcan to Recreate Planetary Cores

    CERN Document Server

    Collins, G W; Benedetti, L R; Benuzzi-Mounaix, A; Cauble, R; Celliers, P M; Danson, C; Da Silva, L B; Gessner, H; Henry, E; Hicks, D G; Huser, G; Jeanloz, R; Koening, M; Lee, K M; Mackinnon, A J; Moon, S J; Neely, D; Notley, M; Pasley, J; Willi, O

    2001-01-01

    An accurate equation of state (EOS) for planetary constituents at extreme conditions is the key to any credible model of planets or low mass stars. However, experimental validation has been carried out on at high pressure (>few Mbar), and then only on the principal Hugoniot. For planetary and stellar interiors, compression occurs from gravitational force so that material states follow a line of isentropic compression (ignoring phase separation) to ultra-high densities. An example of the predicted states for water along the isentrope for Neptune is shown in a figure. The cutaway figure on the left is from Hubbard, and the phase diagram on the right is from Cavazzoni et al. Clearly these states lie at quite a bit lower temperature and higher density than single shock Hugoniot states but they are at higher temperature than can be achieved with accurate diamond anvil experiments. At extreme densities, material states are predicted to have quite unearthly properties such as high temperature superconductivity and l...

  8. Lunar and Planetary Webcam User's Guide

    CERN Document Server

    Mobberley, Martin

    2006-01-01

    Inexpensive webcams are revolutionizing imaging in amateur astronomy by providing an affordable alternative to cooled-chip astronomical CCD cameras, for photographing the brighter astronomical objects. Webcams – costing only a few tens of dollars – are capable of more advanced high resolution work than "normal" digital cameras because their rapid image download speed can freeze fine planetary details, even through the Earth's turbulent atmosphere. Also, their simple construction makes it easy to remove the lens, allowing them to be used at high power at the projected focus of an astronomical telescope. Webcams also connect direct to a PC, so that software can be used to "stack" multiple images, providing a stunning increase in image quality. In the Lunar and Planetary Webcam User’s Guide Martin Mobberley de-mystifies the jargon of webcams and computer processing, and provides detailed hints and tips for imaging the Sun, Moon and planets with a webcam. He looks at each observing target separately, descri...

  9. Equations of State: Gateway to Planetary Origin and Evolution (Invited)

    Science.gov (United States)

    Melosh, J.

    2013-12-01

    Research over the past decades has shown that collisions between solid bodies govern many crucial phases of planetary origin and evolution. The accretion of the terrestrial planets was punctuated by planetary-scale impacts that generated deep magma oceans, ejected primary atmospheres and probably created the moons of Earth and Pluto. Several extrasolar planetary systems are filled with silicate vapor and condensed 'tektites', probably attesting to recent giant collisions. Even now, long after the solar system settled down from its violent birth, a large asteroid impact wiped out the dinosaurs, while other impacts may have played a role in the origin of life on Earth and perhaps Mars, while maintaining a steady exchange of small meteorites between the terrestrial planets and our moon. Most of these events are beyond the scale at which experiments are possible, so that our main research tool is computer simulation, constrained by the laws of physics and the behavior of materials during high-speed impact. Typical solar system impact velocities range from a few km/s in the outer solar system to 10s of km/s in the inner system. Extrasolar planetary systems expand that range to 100s of km/sec typical of the tightly clustered planetary systems now observed. Although computer codes themselves are currently reaching a high degree of sophistication, we still rely on experimental studies to determine the Equations of State (EoS) of materials critical for the correct simulation of impact processes. The recent expansion of the range of pressures available for study, from a few 100 GPa accessible with light gas guns up to a few TPa from current high energy accelerators now opens experimental access to the full velocity range of interest in our solar system. The results are a surprise: several groups in both the USA and Japan have found that silicates and even iron melt and vaporize much more easily in an impact than previously anticipated. The importance of these findings is

  10. Radiation Effects on Spacecraft Structural Materials

    International Nuclear Information System (INIS)

    Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

    2002-01-01

    Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

  11. Windows with an improved energy balance of 30%

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe

    means that both energy losses and transmittance of solar radiation is considered.The final goal of the project was to improve the energy balance of a window with at least 30%. As reference is chosen a common low energy glazing mounted in a wooden frame construction measuring 1188 × 1188 mm2...... the main emphasis has been put on improvement of the frame construction and the interaction between frame and glazing. Several theoretical analyses have been carried out and a prototype construction has been made, that meets the goal of a 30% improvement of the energy balance.The prototype has been tested....... A 30% improvement of the energy balance then corresponds to an reduction in net energy loss of 17 kWh/m2 window area.The frame costruction and the joint between glazing and frame is the thermally weak part of modern windows compared to centre values of the new super insulating glazings. As a result...

  12. The effects of gamma-radiation on lithium-ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, N.; Zhu, J.; Yao, Y.X.; Chen, C.H. [Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China)

    2006-09-15

    Planetary explorations of human beings necessitate the research of the influence of {gamma}-radiation on lithium-ion cells. In this study, the radioactive Co-60 was used as the radiation source. The electrochemical performances of LiCoO{sub 2}/graphite full cells and LiCoO{sub 2}/Li half-cells with a LiPF{sub 6}-based electrolyte were measured before and after the radiation. The structural and compositional changes of the cell components were evaluated by means of X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), and {sup 1}H nuclear magnetic resonance spectroscopy ({sup 1}H NMR). The experimental results indicate that the cell performance is substantially deteriorated after the radiation due to two aspects of changes, i.e. radiation-induced defects in LiCoO{sub 2} and production of carboxyl in the electrolyte. The cell degradation is more pronounced for the LiCoO{sub 2}/C full cells than for LiCoO{sub 2}/Li half-cells owing to the reaction between active lithium and the carboxyl. (author)

  13. Molecular Dications in Planetary Atmospheric Escape

    Directory of Open Access Journals (Sweden)

    Stefano Falcinelli

    2016-08-01

    Full Text Available Fundamental properties of multiply charged molecular ions, such as energetics, structure, stability, lifetime and fragmentation dynamics, are relevant to understand and model the behavior of gaseous plasmas as well as ionosphere and astrophysical environments. Experimental determinations of the Kinetic Energy Released (KER for ions originating from dissociations reactions, induced by Coulomb explosion of doubly charged molecular ions (molecular dications produced by double photoionization of CO2, N2O and C2H2 molecules of interest in planetary atmospheres, are reported. The KER measurement as a function of the ultraviolet (UV photon energy in the range of 28–65 eV was extracted from the electron-ion-ion coincidence spectra obtained by using tunable synchrotron radiation coupled with ion imaging techniques at the ELETTRA Synchrotron Light Laboratory Trieste, Italy. These experiments, coupled with a computational analysis based on a Monte Carlo trajectory simulation, allow assessing the probability of escape for simple ionic species in the upper atmosphere of Mars, Venus and Titan. The measured KER in the case of H+, C+, CH+, CH2+, N+, O+, CO+, N2+ and NO+ fragment ions range between 1.0 and 5.5 eV, being large enough to allow these ionic species to participate in the atmospheric escape from such planets into space. In the case of Mars, we suggest a possible explanation for the observed behavior of the O+ and CO22+ ion density profiles.

  14. Surface Energy Balance in Jakarta and Neighboring Regions As Simulated Using Fifth Mesoscale Model (MM5

    Directory of Open Access Journals (Sweden)

    Yopi Ilhamsyah

    2014-04-01

    Full Text Available The objective of the present research was to assess the surface energy balance particularly in terms of the computed surface energy and radiation balance and the development of boundary layer over Jakarta and Neighboring Regions (JNR by means of numerical model of fifth generation of Mesoscale Model (MM5. The MM5 with four domains of 9 kilometers in spatial resolution presenting the outermost and the innermost of JNR is utilized. The research focuses on the third and fourth domains covering the entire JNR. The description between radiation and energy balance at the surface is obtained from the model. The result showed that energy balance is higher in the city area during daytime. Meanwhile, energy components, e.g., surface sensible and latent heat flux showed that at the sea and in the city areas were higher than other areas. Moreover, ground flux showed eastern region was higher than others. In general, radiation and energy balance was higher in the daytime and lower in the nighttime for all regions. The calculation of Bowen Ratio, the ratio of surface sensible and latent heat fluxes, was also higher in the city area, reflecting the dominations of urban and built-up land in the region. Meanwhile, Bowen Ratio in the rural area dominated by irrigated cropland was lower. It is consistent with changes of land cover properties, e.g. albedo, soil moisture, and thermal characteristics. In addition, the boundary layer is also higher in the city. Meanwhile western region dominated by suburban showed higher boundary layer instead of eastern region.

  15. Development of balanced downflow type surface condensers, (2)

    International Nuclear Information System (INIS)

    Tomida, Akira; Oshima, Yoshikuni; Okochi, Isao; Izumi, Kenkichi.

    1976-01-01

    As the size of the condensers for power generation plants grew large, the new balanced downflow type condenser was developed and completed on the basis of the experiment on steam flow according to the two-dimensional flow model, the analysis of the performance in a tube nest with a computer, and the studies on the effect of outside liquid film and the reheating deaeration of condensate. When the balanced downflow type condensers were adopted for actual plants, the construction, strength and production method were examined, and the reliability of the new condenser was confirmed by the thermal characteristic experiment with the model similar to the actual machine. The condenser comprises a condenser body, supporting plates, cooling tubes, tube plates, water chambers, and reinforcements, and the cooling tubes are arranged so as to exchange heat effectively. The arrangement of tubes is divided into three regions, namely radiation portion, densely arranged portion, and air cooling portion. In the balanced downflow type condensers, the dilution by utilizing condensate is provided against ammonia attack. The apparatuses for the thermal characteristic experiment and the experimental results, and the results of the performance test on the actual balanced downflow type condenser are reported. (Kako, I.)

  16. Pyrometer with tracking balancing

    Science.gov (United States)

    Ponomarev, D. B.; Zakharenko, V. A.; Shkaev, A. G.

    2018-04-01

    Currently, one of the main metrological noncontact temperature measurement challenges is the emissivity uncertainty. This paper describes a pyrometer with emissivity effect diminishing through the use of a measuring scheme with tracking balancing in which the radiation receiver is a null-indicator. In this paper the results of the prototype pyrometer absolute error study in surfaces temperature measurement of aluminum and nickel samples are presented. There is absolute error calculated values comparison considering the emissivity table values with errors on the results of experimental measurements by the proposed method. The practical implementation of the proposed technical solution has allowed two times to reduce the error due to the emissivity uncertainty.

  17. The NASA Planetary Data System Roadmap Study for 2017 - 2026

    Science.gov (United States)

    McNutt, R. L., Jr.; Gaddis, L. R.; Law, E.; Beyer, R. A.; Crombie, M. K.; Ebel, D. S. S.; Ghosh, A.; Grayzeck, E.; Morgan, T. H.; Paganelli, F.; Raugh, A.; Stein, T.; Tiscareno, M. S.; Weber, R. C.; Banks, M.; Powell, K.

    2017-12-01

    NASA's Planetary Data System (PDS) is the formal archive of >1.2 petabytes of data from planetary exploration, science, and research. Initiated in 1989 to address an overall lack of attention to mission data documentation, access, and archiving, the PDS has evolved into an online collection of digital data managed and served by a federation of six science discipline nodes and two technical support nodes. Several ad hoc mission-oriented data nodes also provide complex data interfaces and access for the duration of their missions. The recent Planetary Data System Roadmap Study for 2017 to 2026 involved 15 planetary science community members who collectively prepared a report summarizing the results of an intensive examination of the current state of the PDS and its organization, management, practices, and data holdings (https://pds.jpl.nasa.gov/roadmap/PlanetaryDataSystemRMS17-26_20jun17.pdf). The report summarizes the history of the PDS, its functions and characteristics, and how it has evolved to its present form; also included are extensive references and documentary appendices. The report recognizes that as a complex, evolving, archive system, the PDS must constantly respond to new pressures and opportunities. The report provides details on the challenges now facing the PDS, 19 detailed findings, suggested remediations, and a summary of what the future may hold for planetary data archiving. The findings cover topics such as user needs and expectations, data usability and discoverability (i.e., metadata, data access, documentation, and training), tools and file formats, use of current information technologies, and responses to increases in data volume, variety, complexity, and number of data providers. In addition, the study addresses the possibility of archiving software, laboratory data, and measurements of physical samples. Finally, the report discusses the current structure and governance of the PDS and its impact on how archive growth, technology, and new

  18. Multiscale regime shifts and planetary boundaries

    NARCIS (Netherlands)

    Hughes, T.P.; Carpenter, S.; Rockstrom, J.; Scheffer, M.; Walker, B.

    2013-01-01

    Life on Earth has repeatedly displayed abrupt and massive changes in the past, and there is no reason to expect that comparable planetary-scale regime shifts will not continue in the future. Different lines of evidence indicate that regime shifts occur when the climate or biosphere transgresses a

  19. Bi-Abundance Ionisation Structure of the Wolf-Rayet Planetary Nebula PB 8

    Science.gov (United States)

    Danehkar, A.

    2018-01-01

    The planetary nebula PB 8 around a [WN/WC]-hybrid central star is one of planetary nebulae with moderate abundance discrepancy factors (ADFs 2-3), which could be an indication of a tiny fraction of metal-rich inclusions embedded in the nebula (bi-abundance). In this work, we have constructed photoionisation models to reproduce the optical and infrared observations of the planetary nebula PB 8 using a non-LTE stellar model atmosphere ionising source. A chemically homogeneous model initially used cannot predict the optical recombination lines. However, a bi-abundance model provides a better fit to most of the observed optical recombination lines from N and O ions. The metal-rich inclusions in the bi-abundance model occupy 5.6% of the total volume of the nebula, and are roughly 1.7 times cooler and denser than the mean values of the surrounding nebula. The N/H and O/H abundance ratios in the metal-rich inclusions are 1.0 and 1.7 dex larger than the diffuse warm nebula, respectively. To reproduce the Spitzer spectral energy distribution of PB 8, dust grains with a dust-to-gas ratio of 0.01 (by mass) were also included. It is found that the presence of metal-rich inclusions can explain the heavy element optical recombination lines, while a dual-dust chemistry with different grain species and discrete grain sizes likely produces the infrared continuum of this planetary nebula. This study demonstrates that the bi-abundance hypothesis, which was examined in a few planetary nebulae with large abundance discrepancies (ADFs > 10), could also be applied to those typical planetary nebulae with moderate abundance discrepancies.

  20. What works in planetary science outreach and what doesn't: an attempt to create a functional framing

    Science.gov (United States)

    Urban, Z.

    2014-04-01

    A thorough synthesis of experience from several decades (including 14 years on a full-time basis) of writing in the media and lecturing about the exploration of the Solar System and search for planets of other stars for the general public in Slovakia and in the Czech Republic is presented. The emphasis is given on detailed evaluation of specific feedbacks from readership and audience of various backgrounds and age groups communicated to the author. A list of 10 + 1 main pro arguments is compiled, consisting of reasonings (in addition to scientific or general knowledge/cultural value) like embodiment of our exploratory spirit, colonization, "emergency backup" world or worlds for mankind, comparative planetology as a tool for the explanation and full understanding of Earth's properties, transfer of environmentally unfriendly but irreplaceable (in mid term, at least) technologies to lifeless environments of other planetary bodies, etc. Similarly, a list of 5 main con arguments (like it is wasting of money badly needed to solve a number of urgent social problems, or it is in conflict with valued traditional beliefs) related to planetary exploration or manned and robotic space exploration in general is compiled. A short review of best practices how to counter them is presented alongside. It is demonstrated that one can construct a coherent, balanced framing of planetary science. It assertively supports the relevant efforts in both the general public and special groups involved (for example, enterpreneurs, politicians, members of the media, various activists) while treats the differing opinions and worldviews of critics with respect they deserve. The open conflict, if only in discussion, does not represent any way out. It is counterproductive in both the short-term and the long-term context. In fact, even sharply dissenting opinions often contain some points which can be used, with the help of empathy, psychology and - to be candid - a little, still tolerable dose of