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

Modeling Snow Regime in Cores of Small Planetary Bodies

Science.gov (United States)

Boukaré, C. E.; Ricard, Y. R.; Parmentier, E.; Parman, S. W.

2017-12-01

Observations of present day magnetic field on small planetary bodies such as Ganymede or Mercury challenge our understanding of planetary dynamo. Several mechanisms have been proposed to explain the origin of magnetic fields. Among the proposed scenarios, one family of models relies on snow regime. Snow regime is supported by experimental studies showing that melting curves can first intersect adiabats in regions where the solidifying phase is not gravitationaly stable. First solids should thus remelt during their ascent or descent. The effect of the snow zone on magnetic field generation remains an open question. Could magnetic field be generated in the snow zone? If not, what is the depth extent of the snow zone? How remelting in the snow zone drive compositional convection in the liquid layer? Several authors have tackled this question with 1D-spherical models. Zhang and Schubert, 2012 model sinking of the dense phase as internally heated convection. However, to our knowledge, there is no study on the convection structure associated with sedimentation and phase change at planetary scale. We extend the numerical model developped in [Boukare et al., 2017] to model snow dynamics in 2D Cartesian geometry. We build a general approach for modeling double diffusive convection coupled with solid-liquid phase change and phase separation. We identify several aspects that may govern the convection structure of the solidifying system: viscosity contrast between the snow zone and the liquid layer, crystal size, rate of melting/solidification and partitioning of light components during phase change.

Estimation of a planetary magnetic field using a reduced magnetohydrodynamic model

Directory of Open Access Journals (Sweden)

C. Nabert

2017-03-01

Full Text Available Knowledge of planetary magnetic fields provides deep insights into the structure and dynamics of planets. Due to the interaction of a planet with the solar wind plasma, a rather complex magnetic environment is generated. The situation at planet Mercury is an example of the complexities occurring as this planet's field is rather weak and the magnetosphere rather small. New methods are presented to separate interior and exterior magnetic field contributions which are based on a dynamic inversion approach using a reduced magnetohydrodynamic (MHD model and time-varying spacecraft observations. The methods select different data such as bow shock location information or magnetosheath magnetic field data. Our investigations are carried out in preparation for the upcoming dual-spacecraft BepiColombo mission set out to precisely estimate Mercury's intrinsic magnetic field. To validate our new approaches, we use THEMIS magnetosheath observations to estimate the known terrestrial dipole moment. The terrestrial magnetosheath provides observations from a strongly disturbed magnetic environment, comparable to the situation at Mercury. Statistical and systematic errors are considered and their dependence on the selected data sets are examined. Including time-dependent upstream solar wind variations rather than averaged conditions significantly reduces the statistical error of the estimation. Taking the entire magnetosheath data along the spacecraft's trajectory instead of only the bow shock location into account further improves accuracy of the estimated dipole moment.

Saturn's Magnetic Field from the Cassini Grand Finale orbits

Science.gov (United States)

Dougherty, M. K.; Cao, H.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

2017-12-01

The fundamental aims of the Cassini magnetometer investigation during the Cassini Grand Finale orbits were determination of Saturn's internal planetary magnetic field and the rotation rate of the deep interior. The unique geometry of the orbits provided an unprecedented opportunity to measure the intrinsic magnetic field at close distances never before encountered. The surprising close alignment of Saturn's magnetic axis with its spin axis, known about since the days of Pioneer 11, has been a focus of the team's analysis since Cassini Saturn Orbit Insertion. However, the varying northern and southern magnetospheric planetary period oscillations, which fill the magnetosphere, has been a factor in masking the field signals from the interior. Here we describe an overview of the magnetometer results from the Grand Finale orbits, including confirmation of the extreme axisymmetric nature of the planetary magnetic field, implications for knowledge of the rotation rate and the behaviour of external magnetic fields (arising from the ring current, field aligned currents both at high and low latitudes and the modulating effect of the planetary period oscillations).

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.

Influence of large-scale zonal flows on the evolution of stellar and planetary magnetic fields

Science.gov (United States)

Petitdemange, Ludovic; Schrinner, Martin; Dormy, Emmanuel; ENS Collaboration

2011-10-01

Zonal flows and magnetic field are present in various objects as accretion discs, stars and planets. Observations show a huge variety of stellar and planetary magnetic fields. Of particular interest is the understanding of cyclic field variations, as known from the sun. They are often explained by an important Ω-effect, i.e., by the stretching of field lines because of strong differential rotation. We computed the dynamo coefficients for an oscillatory dynamo model with the help of the test-field method. We argue that this model is of α2 Ω -type and here the Ω-effect alone is not responsible for its cyclic time variation. More general conditions which lead to dynamo waves in global direct numerical simulations are presented. Zonal flows driven by convection in planetary interiors may lead to secondary instabilities. We showed that a simple, modified version of the MagnetoRotational Instability, i.e., the MS-MRI can develop in planteray interiors. The weak shear yields an instability by its constructive interaction with the much larger rotation rate of planets. We present results from 3D simulations and show that 3D MS-MRI modes can generate wave pattern at the surface of the spherical numerical domain. Zonal flows and magnetic field are present in various objects as accretion discs, stars and planets. Observations show a huge variety of stellar and planetary magnetic fields. Of particular interest is the understanding of cyclic field variations, as known from the sun. They are often explained by an important Ω-effect, i.e., by the stretching of field lines because of strong differential rotation. We computed the dynamo coefficients for an oscillatory dynamo model with the help of the test-field method. We argue that this model is of α2 Ω -type and here the Ω-effect alone is not responsible for its cyclic time variation. More general conditions which lead to dynamo waves in global direct numerical simulations are presented. Zonal flows driven by convection

A New Model of Jupiter's Magnetic Field From Juno's First Nine Orbits

Science.gov (United States)

Connerney, J. E. P.; Kotsiaros, S.; Oliversen, R. J.; Espley, J. R.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Herceg, M.; Bloxham, J.; Moore, K. M.; Bolton, S. J.; Levin, S. M.

2018-03-01

A spherical harmonic model of the magnetic field of Jupiter is obtained from vector magnetic field observations acquired by the Juno spacecraft during its first nine polar orbits about the planet. Observations acquired during eight of these orbits provide the first truly global coverage of Jupiter's magnetic field with a coarse longitudinal separation of 45° between perijoves. The magnetic field is represented with a degree 20 spherical harmonic model for the planetary ("internal") field, combined with a simple model of the magnetodisc for the field ("external") due to distributed magnetospheric currents. Partial solution of the underdetermined inverse problem using generalized inverse techniques yields a model ("Juno Reference Model through Perijove 9") of the planetary magnetic field with spherical harmonic coefficients well determined through degree and order 10, providing the first detailed view of a planetary dynamo beyond Earth.

Planetary Dynamos: Investigations of Saturn and Ancient Mars

Energy Technology Data Exchange (ETDEWEB)

Stanley, Sabine [University of Toronto

2012-04-18

Magnetic field observations by spacecraft missions have provided vital information on planetary dynamos. The four giant planets as well as Earth, Mercury and Ganymede have observable magnetic fields generated by active dynamos. In contrast, Moon and Mars only have remanent crustal fields from dynamo action in their early histories. A variety of magnetic field morphologies and intensities can be found in the solar system. We have found that some of the differences between planetary magnetic fields can be explained as the result of the presence of boundary thermal variations or stably-stratified layers. In this talk, I will discuss how dynamos are affected by these complications and discuss the implications for Mars’ magnetic dichotomy and Saturn’s extremely axisymmetric magnetic field.

Planetary magnetism

International Nuclear Information System (INIS)

Dolginov, Sh.Sh.

1977-01-01

Experimental data on magnetic fields of planets are surveyed. The magnetic fields of the Earth, Jupiter, Mars, Mercury, Venus, and the Moon are considered in detail. A similarity of the physical models of both the planets of the Earth group and the giant planets was revealed. The fields of the planets and of the Earth are compared in the scheme of the precession dynamo and in the kinematic scheme. Proceeding from the assumption that the Poincare forces and their ratio to other forces are model-similar in the cores of all the planets, the values of Hsub(i)/Hsub(E) are calculated, where Hsub(i) and Hsub(E) are the field strengths of the i-th planet and that of the Earth. The experimental data on the dynamic compression of the Mercury confirm the calculations made. It is concluded that the problem of the origin and moving forces of the terrestrial magnetic field may be resolved only within the framework of comparative planetology

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

Internal magnetic target of proton synchrotron

International Nuclear Information System (INIS)

Gachurin, V.V.; Kats, M.M.; Kondrat'ev, L.N.; Rogal', A.D.; Rusinov, V.Yu.

1988-01-01

Proton extraction from a synchrotron by means of an internal target of magnetized iron is described. The particles that are aimed at the target pass directly through it and are deflected by the internal magnetic field of the target in the extraction direction. The general properties of magnetic targets are examined theoretically and a specific devices and results of its testing are described

Internal structure of magnetic endosomes

Science.gov (United States)

Rivière, C.; Wilhelm, C.; Cousin, F.; Dupuis, V.; Gazeau, F.; Perzynski, R.

2007-01-01

The internal structure of biological vesicles filled with magnetic nanoparticles is investigated using the following complementary analyses: electronic transmission microscopy, dynamic probing by magneto-optical birefringence and structural probing by Small Angle Neutron Scattering (SANS). These magnetic vesicles are magnetic endosomes obtained via a non-specific interaction between cells and anionic magnetic iron oxide nanoparticles. Thanks to a magnetic purification process, they are probed at two different stages of their formation within HeLa cells: (i) adsorption of nanoparticles onto the cellular membrane and (ii) their subsequent internalisation within endosomes. Differences in the microenvironment of the magnetic nanoparticles at those two different stages are highlighted here. The dynamics of magnetic nanoparticles adsorbed onto cellular membranes and confined within endosomes is respectively 3 and 5 orders of magnitude slower than for isolated magnetic nanoparticles in aqueous media. Interestingly, SANS experiments show that magnetic endosomes have an internal structure close to decorated vesicles, with magnetic nanoparticles locally decorating the endosome membrane, inside their inner-sphere. These results, important for future biomedical applications, suggest that multiple fusions of decorated vesicles are the biological processes underlying the endocytosis of that kind of nanometric materials.

The international magnetic fusion energy program

International Nuclear Information System (INIS)

Fowler, T.K.

1988-01-01

In May of 1988, the long tradition of international cooperation in magnetic fusion energy research culminated in the initiation of design work on the International Thermonuclear Experimental Reactor (ITER). If eventually constructed in the 1990s, ITER would be the world's first magnetic fusion reactor. This paper discusses the background events that led to ITER and the present status of the ITER activity. This paper presents a brief summary of the technical, political, and organizational activities that have led to the creation of the ITER design activity. The ITER activity is now the main focus of international cooperation in magnetic fusion research and one of the largest international cooperative efforts in all of science. 2 refs., 12 figs

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.

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.

Radio scintillations observed during atmospheric occultations of Voyager: Internal gravity waves at Titan and magnetic field orientations at Jupiter and Saturn. Ph.D. Thesis

Science.gov (United States)

Hinson, D. P.

1983-01-01

The refractive index of planetary atmospheres at microwave frequencies is discussed. Physical models proposed for the refractive irregularities in the ionosphere and neutral atmosphere serve to characterize the atmospheric scattering structures, and are used subsequently to compute theoretical scintillation spectra for comparison with the Voyager occultation measurements. A technique for systematically analyzing and interpreting the signal fluctuations observed during planetary occultations is presented and applied to process the dual-wavelength data from the Voyager radio occultations by Jupiter, Saturn, and Titan. Results concerning the plasma irregularities in the upper ionospheres of Jupiter and Saturn are reported. The measured orientation of the irregularities is used to infer the magnetic field direction at several locations in the ionospheres of these two planets; the occultation measurements conflict with the predictions of Jovian magnetic field models, but generally confirm current models of Saturn's field. Wave parameters, including the vertical fluxes of energy and momentum, are estimated, and the source of the internal gravity waves discovered in Titan's upper atmosphere is considered.

The international magnetic fusion energy program

Energy Technology Data Exchange (ETDEWEB)

Fowler, T.K.

1988-10-06

In May of 1988, the long tradition of international cooperation in magnetic fusion energy research culminated in the initiation of design work on the International Thermonuclear Experimental Reactor (ITER). If eventually constructed in the 1990s, ITER would be the world's first magnetic fusion reactor. This paper discusses the background events that led to ITER and the present status of the ITER activity. This paper presents a brief summary of the technical, political, and organizational activities that have led to the creation of the ITER design activity. The ITER activity is now the main focus of international cooperation in magnetic fusion research and one of the largest international cooperative efforts in all of science. 2 refs., 12 figs.

International Seminar on Nuclear War and Planetary Emergencies : 46th Session : The Role of Science in the Third Millennium

CERN Document Server

2014-01-01

Proceedings of the 46th Session of the International Seminars on Nuclear War and Planetary Emergencies held in "E. Majorana" Centre for Scientific Culture, Erice, Sicily. This Seminar has again gathered, in 2013, over 100 scientists from 43 countries in an interdisciplinary effort that has been going on for the last 32 years, to examine and analyze planetary problems which had been followed up, all year long, by the World Federation of Scientists' Permanent Monitoring Panels.

Internal Gravity Waves in the Magnetized Solar Atmosphere. I. Magnetic Field Effects

Energy Technology Data Exchange (ETDEWEB)

Vigeesh, G.; Steiner, O. [Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg (Germany); Jackiewicz, J., E-mail: vigeesh@leibniz-kis.de [New Mexico State University, Department of Astronomy, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003 (United States)

2017-02-01

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magnetoacoustic waves. Here, we present a study of the acoustic-gravity wave spectrum emerging from a realistic, self-consistent simulation of solar (magneto)convection. A magnetic field free, hydrodynamic simulation and a magnetohydrodynamic (MHD) simulation with an initial, vertical, homogeneous field of 50 G flux density were carried out and compared with each other to highlight the effect of magnetic fields on the internal gravity wave propagation in the Sun’s atmosphere. We find that the internal gravity waves are absent or partially reflected back into the lower layers in the presence of magnetic fields and argue that the suppression is due to the coupling of internal gravity waves to slow magnetoacoustic waves still within the high- β region of the upper photosphere. The conversion to Alfvén waves is highly unlikely in our model because there is no strongly inclined magnetic field present. We argue that the suppression of internal waves observed within magnetic flux concentrations may also be due to nonlinear breaking of internal waves due to vortex flows that are ubiquitously present in the upper photosphere and the chromosphere.

International Ultraviolet Explorer satellite observations of seven high-excitation planetary nebulae.

Science.gov (United States)

Aller, L H; Keyes, C D

1980-03-01

Observations of seven high-excitation planetary nebulae secured with the International Ultraviolet Explorer (IUE) satellite were combined with extensive ground-based data to obtain electron densities, gas kinetic temperatures, and ionic concentrations. We then employed a network of theoretical model nebulae to estimate the factors by which observed ionic concentrations must be multiplied to obtain elemental abundances. Comparison with a large sample of nebulae for which extensive ground-based observations have been obtained shows nitrogen to be markedly enhanced in some of these objects. Possibly most, if not all, high-excitation nebulae evolve from stars that have higher masses than progenitors of nebulae of low-to-moderate excitation.

Does the planetary dynamo go cycling on? Re-examining the evidence for cycles in magnetic reversal rate

Science.gov (United States)

Melott, Adrian L.; Pivarunas, Anthony; Meert, Joseph G.; Lieberman, Bruce S.

2018-01-01

The record of reversals of the geomagnetic field has played an integral role in the development of plate tectonic theory. Statistical analyses of the reversal record are aimed at detailing patterns and linking those patterns to core-mantle processes. The geomagnetic polarity timescale is a dynamic record and new paleomagnetic and geochronologic data provide additional detail. In this paper, we examine the periodicity revealed in the reversal record back to 375 million years ago (Ma) using Fourier analysis. Four significant peaks were found in the reversal power spectra within the 16-40-million-year range (Myr). Plotting the function constructed from the sum of the frequencies of the proximal peaks yield a transient 26 Myr periodicity, suggesting chaotic motion with a periodic attractor. The possible 16 Myr periodicity, a previously recognized result, may be correlated with `pulsation' of mantle plumes and perhaps; more tentatively, with core-mantle dynamics originating near the large low shear velocity layers in the Pacific and Africa. Planetary magnetic fields shield against charged particles, which can give rise to radiation at the surface and ionize the atmosphere, which is a loss mechanism particularly relevant to M stars. Understanding the origin and development of planetary magnetic fields can shed light on the habitable zone.

Little Earth Experiment: An instrument to model planetary cores.

Science.gov (United States)

Aujogue, Kélig; Pothérat, Alban; Bates, Ian; Debray, François; Sreenivasan, Binod

2016-08-01

In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10 T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core.

First Numerical Simulations of Turbulent Dynamos Driven by Libration, Precession and Tides in Triaxial Ellipsoids - An Alternative Route for Planetary Magnetism

Science.gov (United States)

Le Bars, M.; Kanuganti, S. R.; Favier, B.

2017-12-01

Most of the time, planetary dynamos are - tacitly or not - associated with thermo-solutal convection. The convective dynamo model has indeed proven successful to explain the current Earth's magnetic field. However, its results are sometimes difficult to reconcile with observational data and its validity can be questioned for several celestial bodies. For instance, the small size of the Moon and Ganymede makes it difficult to maintain a sufficient temperature gradient to sustain convection and to explain their past and present magnetic fields, respectively. The same caveat applies to the growing number of planetesimals shown to have generated magnetic fields in their early history. Finally, the energy budget of the early Earth is difficult to reconcile with a convective dynamo before the onset of inner core growth. Significant effort has thus been put into finding new routes for planetary dynamo. In particular, the rotational dynamics of planets, moons and small bodies, where their average spinning motion is periodically perturbed by the small mechanical forcings of libration, precession and/or tides, is now widely accepted as an efficient source of core turbulence. The underlying mechanism relies on a parametric instability where the inertial waves of the rotating fluid core are resonantly excited by the small forcing, leading to exponential growth and bulk filling intense motions, pumping their energy from the orbital dynamics. Dynamos driven by mechanical forcing have been suggested for the Moon, Mars, Io, the early Earth, etc. However, the real dynamo capacity of the corresponding flows has up-to-now been studied only in very limited cases, with simplified spherical/spheroidal geometries and/or overly viscous fluids. We will present here the first numerical simulations of dynamos driven by libration, precession and tides, in the triaxial ellipsoidal geometry and in the turbulent regime relevant for planetary cores. We will describe the numerical techniques

Magnetic properties of nanocrystalline Fe–10%Ni alloy obtained by planetary ball mills

International Nuclear Information System (INIS)

Hamzaoui, Rabah; Elkedim, Omar

2013-01-01

Highlights: •Solid solution formation accompanied by a grain refinement for nanocrystalline Fe-Ni. •The shock mode process (SMP) prevails when Ω > >ω. •The friction mode process (FMP) is stronger when Ω < <ω. •The FMP leads to the formation of alloys exhibiting a soft magnetic behavior. -- Abstract: Planetary ball mill PM 400 from Retsch (with different milling times for Ω = 400 rpm, ω = 800 rpm) and P4 vario ball mill from Fritsch (with different milling conditions (Ω/ω), Ω and ω being the disc and the vial rotation speeds, respectively) are used for obtaining nanocrystalline Fe–10wt% Ni. The structure and magnetic properties are studied by using X-ray diffraction, SEM and hysteresis measurements, respectively. The bcc-Fe(Ni) phase formation is identified by X-ray diffraction. The higher the shock power and the higher milling time are, the larger the bcc lattice parameter and the lower the grain size. The highest value of the coercivity is 1600 A/m for Fe–10 wt.%Ni (with shock mode (424 rpm/100 rpm) after 36 h of milling), while the lowest value is 189 A/m for (400 rpm/800 rpm) after 72 h of milling. The milling performed in the friction mode has been found to lead the formation of alloys exhibiting a soft magnetic behavior for nanocrystalline Fe–10%Ni

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...

The TMT International Observatory: A quick overview of future opportunities for planetary science exploration

Science.gov (United States)

Dumas, Christophe; Dawson, Sandra; Otarola, Angel; Skidmore, Warren; Squires, Gordon; Travouillon, Tony; Greathouse, Thomas K.; Li, Jian-Yang; Lu, Junjun; Marchis, Frank; Meech, Karen J.; Wong, Michael H.

2015-11-01

The construction of the Thirty-Meter-Telescope International Observatory (TIO) is scheduled to take about eight years, with first-light currently planned for the horizon 2023/24, and start of science operations soon after. Its innovative design, the unequalled astronomical quality of its location, and the scientific capabilities that will be offered by its suite of instruments, all contribute to position TIO as a major ground-based facility of the next decade.In this talk, we will review the expected observing performances of the facility, which will combine adaptive-optics corrected wavefronts with powerful imaging and spectroscopic capabilities. TMT will enable ground-based exploration of our solar system - and planetary systems at large - at a dramatically enhanced sensitivity and spatial resolution across the visible and near-/thermal- infrared regimes. This sharpened vision, spanning the study of planetary atmospheres, ring systems, (cryo-)volcanic activity, small body populations (asteroids, comets, trans-Neptunian objects), and exoplanets, will shed new lights on the processes involved in the formation and evolution of our solar system, including the search for life outside the Earth, and will expand our understanding of the physical and chemical properties of extra-solar planets, complementing TIO's direct studies of planetary systems around other stars.TIO operations will meet a wide range of observing needs. Observing support associated with "classical" and "queue" modes will be offered (including some flavors of remote observing). The TIO schedule will integrate observing programs so as to optimize scientific outputs and take into account the stringent observing time constraints often encountered for observations of our solar system such as, for instance, the scheduling of target-of-oportunity observations, the implementation of short observing runs, or the support of long-term "key-science" programmes.Complementary information about TIO, and the

Reports and recommendations from COSPAR Planetary Exploration Committee (PEX) & International Lunar Exploration Working Group (ILEWG)

Science.gov (United States)

Ehrenfreund, Pascale; Foing, Bernard

2014-05-01

In response to the growing importance of space exploration, the objectives of the COSPAR Panel on Exploration (PEX) are to provide high quality, independent science input to support the development of a global space exploration program while working to safeguard the scientific assets of solar system bodies. PEX engages with COSPAR Commissions and Panels, science foundations, IAA, IAF, UN bodies, and IISL to support in particular national and international space exploration working groups and the new era of planetary exploration. COSPAR's input, as gathered by PEX, is intended to express the consensus view of the international scientific community and should ultimately provide a series of guidelines to support future space exploration activities and cooperative efforts, leading to outstanding scientific discoveries, opportunities for innovation, strategic partnerships, technology progression, and inspiration for people of all ages and cultures worldwide. We shall focus on the lunar exploration aspects, where the COSPAR PEX is building on previous COSPAR, ILEWG and community conferences. An updated COSPAR PEX report is published and available online (Ehrenfreund P. et al, COSPAR planetary exploration panel report, http://www.gwu.edu/~spi/assets/COSPAR_PEX2012.pdf). We celebrate 20 years after the 1st International Conference on Exploration and Utilisation of the Moon at Beatenberg in June 1994. The International Lunar Exploration Working Group (ILEWG) was established the year after in April 1995 at an EGS meeting in Hamburg, Germany. As established in its charter, this working group reports to COSPAR and is charged with developing an international strategy for the exploration of the Moon (http://sci.esa.int/ilewg/ ). It discusses coordination between missions, and a road map for future international lunar exploration and utilisation. It fosters information exchange or potential and real future lunar robotic and human missions, as well as for new scientific and

The internal kinematics of the planetary nebula NGC 650/1

International Nuclear Information System (INIS)

Taylor, K.

1979-01-01

Hα and [N II], lambda 6584 line profiles from the bright lobes of planetary nebula NGC 650/1 have been obtained. These emission lines show a very strong symmetrical triple-peak velocity structure, not observed previously to the author's knowledge in planetary nebulae. Models are tentatively proposed to explain both the velocity data and the nebula's optical appearance. The velocity splitting amounts to approximately 62 km/s and the rest frame of the nebula is found to have a heliocentric radial velocity of -19 +- 2 km/s. (author)

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.

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.

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

NEWTON - NEW portable multi-sensor scienTific instrument for non-invasive ON-site characterization of rock from planetary surface and sub-surfaces

Science.gov (United States)

Díaz-Michelena, M.; de Frutos, J.; Ordóñez, A. A.; Rivero, M. A.; Mesa, J. L.; González, L.; Lavín, C.; Aroca, C.; Sanz, M.; Maicas, M.; Prieto, J. L.; Cobos, P.; Pérez, M.; Kilian, R.; Baeza, O.; Langlais, B.; Thébault, E.; Grösser, J.; Pappusch, M.

2017-09-01

In space instrumentation, there is currently no instrument dedicated to susceptibly or complete magnetization measurements of rocks. Magnetic field instrument suites are generally vector (or scalar) magnetometers, which locally measure the magnetic field. When mounted on board rovers, the electromagnetic perturbations associated with motors and other elements make it difficult to reap the benefits from the inclusion of such instruments. However, magnetic characterization is essential to understand key aspects of the present and past history of planetary objects. The work presented here overcomes the limitations currently existing in space instrumentation by developing a new portable and compact multi-sensor instrument for ground breaking high-resolution magnetic characterization of planetary surfaces and sub-surfaces. This new technology introduces for the first time magnetic susceptometry (real and imaginary parts) as a complement to existing compact vector magnetometers for planetary exploration. This work aims to solve the limitations currently existing in space instrumentation by means of providing a new portable and compact multi-sensor instrument for use in space, science and planetary exploration to solve some of the open questions on the crustal and more generally planetary evolution within the Solar System.

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

Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Reactor

International Nuclear Information System (INIS)

Tsvetkov, Pavel V.; Hart, Ron R.; King, Don B.; Rochau, Gary E.

2006-01-01

Fission energy can be used directly if the kinetic energy of fission fragments is converted to electricity and/or thrust before turning into heat. The completed US DOE NERI Direct Energy Conversion (DEC) Power Production project indicates that viable DEC systems are possible. The US DOE NERI DEC Proof of Principle project began in October of 2002 with the goal to demonstrate performance principles of DEC systems. One of the emerging DEC concepts is represented by fission fragment magnetic collimator reactors (FFMCR). Safety, simplicity, and high conversion efficiency are the unique advantages offered by these systems. In the FFMCR, the basic energy source is the kinetic energy of fission fragments. Following escape from thin fuel layers, they are captured on magnetic field lines and are directed out of the core and through magnetic collimators to produce electricity and thrust. The exiting flow of energetic fission fragments has a very high specific impulse that allows efficient planetary surface power and interstellar propulsion without carrying any conventional propellant onboard. The objective of this work was to determine technological feasibility of the concept. This objective was accomplished by producing the FFMCR design and by analysis of its performance characteristics. The paper presents the FFMCR concept, describes its development to a technologically feasible level and discusses obtained results. Performed studies offer efficiencies up to 90% and velocities approaching speed of light as potentially achievable. The unmanned 10-tons probe with 1000 MW FFMCR propulsion unit would attain mission velocity of about 2% of the speed of light. If the unit is designed for 4000 MW, then in 10 years the unmanned 10-tons probe would attain mission velocity of about 10% of the speed of light

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

Magnetic field measurements using the transient internal probe (TIP)

International Nuclear Information System (INIS)

Galambos, J.P.; Bohnet, M.A.; Jarboe, T.R.; Mattick, A.T.

1995-01-01

Knowledge of the internal magnetic field profile in hot plasmas is fundamental to understanding the structure and behavior of the current profile. The transient internal probe (TIP) is a novel diagnostic designed to measure internal magnetic fields in hot plasmas. The diagnostic involves shooting a magneto-optic probe through the plasma at high velocities (greater than 2 km/s) using a two stage light gas gun. Local fields are obtained by illuminating the probe with an argon ion laser and measuring the amount of Faraday rotation in the reflected beam. Initial development of the diagnostic is complete. Results of magnetic field measurements conducted at 2 km/s will be presented. Helium muzzle gas introduction to the plasma chamber has been limited to less than 0.4 Torr-ell. Magnetic field resolution of 40 Gauss and spatial resolution of 5 mm have been achieved. System frequency response is 10 MHz

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.

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.

Dovetail spoke internal permanent magnet machine

Science.gov (United States)

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-08-23

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

Internal Stresses in Wires for High Field Magnets

International Nuclear Information System (INIS)

Han, K.; Embury, J.D.; Lawson, A.C.; Von Dreele, R.B.; Wood, J.T.; Richardson, J.W. Jr.

1998-01-01

The codeformation of Cu-Ag or Cu-Nb composite wires used for high field magnets has a number of important microstructural consequences, including the production of very fine scale structures, the development of very high internal surface area to volume ratios during the drawing and the storage of defects at interphase interfaces. In addition, the fabrication and codeformation of phases which differ in crystal structure, thermal expansion, elastic modulus and lattice parameter lead to the development of short wavelength internal stresses. These internal stresses are measured by neutron diffraction and transmission electron microscopy as a function of the imposed drawing strain. The internal stresses lead to important changes in elastic plastic response which can be related to both magnet design and service life and these aspects will be described in detail

Magnetic Fields Recorded by Chondrules Formed in Nebular Shocks

Science.gov (United States)

Mai, Chuhong; Desch, Steven J.; Boley, Aaron C.; Weiss, Benjamin P.

2018-04-01

Recent laboratory efforts have constrained the remanent magnetizations of chondrules and the magnetic field strengths to which the chondrules were exposed as they cooled below their Curie points. An outstanding question is whether the inferred paleofields represent the background magnetic field of the solar nebula or were unique to the chondrule-forming environment. We investigate the amplification of the magnetic field above background values for two proposed chondrule formation mechanisms, large-scale nebular shocks and planetary bow shocks. Behind large-scale shocks, the magnetic field parallel to the shock front is amplified by factors of ∼10–30, regardless of the magnetic diffusivity. Therefore, chondrules melted in these shocks probably recorded an amplified magnetic field. Behind planetary bow shocks, the field amplification is sensitive to the magnetic diffusivity. We compute the gas properties behind a bow shock around a 3000 km radius planetary embryo, with and without atmospheres, using hydrodynamics models. We calculate the ionization state of the hot, shocked gas, including thermionic emission from dust, thermal ionization of gas-phase potassium atoms, and the magnetic diffusivity due to Ohmic dissipation and ambipolar diffusion. We find that the diffusivity is sufficiently large that magnetic fields have already relaxed to background values in the shock downstream where chondrules acquire magnetizations, and that these locations are sufficiently far from the planetary embryos that chondrules should not have recorded a significant putative dynamo field generated on these bodies. We conclude that, if melted in planetary bow shocks, chondrules probably recorded the background nebular field.

Increasing Underrepresented Students in Geophysics and Planetary Science Through the Educational Internship in Physical Sciences (EIPS)

Science.gov (United States)

Terrazas, S.; Olgin, J. G.; Enriquez, F.

2017-12-01

The number of underrepresented minorities pursuing STEM fields, specifically in the sciences, has declined in recent times. In response, the Educational Internship in Physical Sciences (EIPS), an undergraduate research internship program in collaboration with The University of Texas at El Paso (UTEP) Geological Sciences Department and El Paso Community College (EPCC), was created; providing a mentoring environment so that students can actively engage in science projects with professionals in their field so as to gain the maximum benefits in an academic setting. This past year, interns participated in planetary themed projects which exposed them to the basics of planetary geology, and worked on projects dealing with introductory digital image processing and synthesized data on two planetary bodies; Pluto and Enceladus respectively. Interns harnessed and built on what they have learned through these projects, and directly applied it in an academic environment in solar system astronomy classes at EPCC. Since the majority of interns are transfer students or alums from EPCC, they give a unique perspective and dimension of interaction; giving them an opportunity to personally guide and encourage current students there on available STEM opportunities. The goal was to have interns gain experience in planetary geology investigations and networking with professionals in the field; further promoting their interests and honing their abilities for future endeavors in planetary science. The efficacy of these activities toward getting interns to pursue STEM careers, enhance their education in planetary science, and teaching key concepts in planetary geophysics are demonstrated in this presentation.

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)

The Juno Magnetic Field Investigation

DEFF Research Database (Denmark)

Connerney, J. E. P.; Benn, Mathias; Bjarnø, Jonas Bækby

2017-01-01

The Juno Magnetic Field investigation (MAG) characterizes Jupiter’s planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor ...

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

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

Planetary Produced Axionlike Particles and Gamma-Ray Flashes

International Nuclear Information System (INIS)

Liolios, Anastasios

2008-01-01

Axion-like particles could be created in nuclear disintegrations and deexitations of natural radionuclides present in the interior of the planets. For the Earth and the other planets with a surrounding magnetosphere, axion production could result to gamma and X-ray emission, originating from axion to photon conversion in the planetary magnetic fields. The estimated planetary axion fluxes as well as the related gamma ray fluxes from Earth and the giant planets of our solar system are given along with the axion coupling to ordinary matter. A possible connection with the enigmatic Terrestrial Gamma-ray Flashes (TGFs) discovered in 1994 by CGRO/BATSE and also detected with the RHESSI satellite, is also discussed.

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.

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.

New Indivisible Planetary Science Paradigm: Consequence of Questioning Popular Paradigms

Science.gov (United States)

Marvin Herndon, J.

2014-05-01

removed, pressure began to build in the compressed rocky kernel of Earth and eventually the rigid crust began to crack. The major energy source for planetary decompression and for heat emplacement at the base of the crust is the stored energy of protoplanetary compression. In response to decompression-driven volume increases, cracks form to increase surface area and fold-mountain ranges form to accommodate changes in curvature. One of the most profound mysteries of modern planetary science is this: As the terrestrial planets are more-or-less of common chondritic composition, how does one account for the marked differences in their surface dynamics? Differences among the inner planets are principally due to the degree of compression experienced. Planetocentric georeactor nuclear fission, responsible for magnetic field generation and concomitant heat production, is applicable to compressed and non-compressed planets and large moons. The internal composition of Mercury is calculated based upon an analogy with the deep-Earth mass ratio relationships. The origin and implication of Mercurian hydrogen geysers is described. Besides Earth, only Venus appears to have sustained protoplanetary compression; the degree of which might eventually be estimated from understanding Venetian surface geology. A basis is provided for understanding that Mars essentially lacks a 'geothermal gradient' which implies potentially greater subsurface water reservoir capacity than previously expected. Resources at NuclearPlanet.com .

FOREWORD: International Conference on Planetary Boundary Layer and Climate Change

Science.gov (United States)

Djolov, G.; Esau, I.

2010-05-01

One of the greatest achievements of climate science has been the establisment of the concept of climate change on a multitude of time scales. The Earth's complex climate system does not allow a straightforward interpretation of dependences between the external parameter perturbation, internal stochastic system dynamics and the long-term system response. The latter is usually referred to as climate change in a narrow sense (IPCC, 2007). The focused international conference "Planetary Boundary Layers and Climate Change" has addressed only time scales and dynamical aspects of climate change with possible links to the turbulent processes in the Planetary Boundary Layer (PBL). Although limited, the conference topic is by no means singular. One should clearly understand that the PBL is the layer where 99% of biosphere and human activity are concentrated. The PBL is the layer where the energy fluxes, which are followed by changes in cryosphere and other known feedbacks, are maximized. At the same time, the PBL processes are of a naturally small scale. What is the averaged long-term effect of the small-scale processes on the long-term climate dynamics? Can this effect be recognized in existing long-term paleo-climate data records? Can it be modeled? What is the current status of our theoretical understanding of this effect? What is the sensitivity of the climate model projections to the representation of small-scale processes? Are there significant indirect effects, e.g. through transport of chemical components, of the PBL processes on climate? These and other linked questions have been addressed during the conference. The Earth's climate has changed many times during the planet's history, with events ranging from ice ages to long periods of warmth. Historically, natural factors such as the amount of energy released from the Sun, volcanic eruptions and changes in the Earth's orbit have affected the Earth's climate. Beginning late in the 18th century, human activities

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

The internal structure of magnetic nanoparticles determines the magnetic response

Czech Academy of Sciences Publication Activity Database

Pacáková, Barbara; Kubíčková, Simona; Salas, G.; Mantlíková, Alice; Marciello, M.; Morales, M.P.; Nižňanský, D.; Vejpravová, Jana

2017-01-01

Roč. 9, č. 16 (2017), s. 5129-5140 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-01953S Institutional support: RVO:68378271 Keywords : nanoparticles * single-domain * internal structure Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 7.367, year: 2016

A Comparative Analysis of the Magnetic Field Signals over Impact Structures on the Earth, Mars and the Moon

Science.gov (United States)

Isac, Anca; Mandea, Mioara; Purucker, Michael; Langlais, Benoit

2015-01-01

An improved description of magnetic fields of terrestrial bodies has been obtained from recent space missions, leading to a better characterization of the internal fields including those of crustal origin. One of the striking differences in their crustal magnetic field is the signature of large impact craters. A comparative analysis of the magnetic characteristics of these structures can shed light on the history of their respective planetary-scale magnetic dynamos. This has motivated us to identify impact craters and basins, first by their quasi-circular features from the most recent and detailed topographic maps and then from available global magnetic field maps. We have examined the magnetic field observed above 27 complex craters on the Earth, 34 impact basins on Mars and 37 impact basins on the Moon. For the first time, systematic trends in the amplitude and frequency of the magnetic patterns, inside and outside of these structures are observed for all three bodies. The demagnetization effects due to the impact shock wave and excavation processes have been evaluated applying the Equivalent Source Dipole forward modeling approach. The main characteristics of the selected impact craters are shown. The trends in their magnetic signatures are indicated, which are related to the presence or absence of a planetary-scale dynamo at the time of their formation and to impact processes. The low magnetic field intensity at center can be accepted as the prime characteristic of a hypervelocity impact and strongly associated with the mechanics of impact crater formation. In the presence of an active internal field, the process of demagnetization due to the shock impact is associated with post-impact remagnetization processes, generating a more complex magnetic signature.

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.

Magnetic resonance imaging of the internal auditory canal

International Nuclear Information System (INIS)

Daniels, D.L.; Herfkins, R.; Koehler, P.R.; Millen, S.J.; Shaffer, K.A.; Williams, A.L.; Haughton, V.M.

1984-01-01

Three patients with exclusively or predominantly intracanalicular neuromas and 5 with presumably normal internal auditory canals were examined with prototype 1.4- or 1.5-tesla magnetic resonance (MR) scanners. MR images showed the 7th and 8th cranial nerves in the internal auditory canal. The intracanalicular neuromas had larger diameter and slightly greater signal strength than the nerves. Early results suggest that minimal enlargement of the nerves can be detected even in the internal auditory canal

Special issue on enabling open and interoperable access to Planetary Science and Heliophysics databases and tools

Science.gov (United States)

2018-01-01

The large amount of data generated by modern space missions calls for a change of organization of data distribution and access procedures. Although long term archives exist for telescopic and space-borne observations, high-level functions need to be developed on top of these repositories to make Planetary Science and Heliophysics data more accessible and to favor interoperability. Results of simulations and reference laboratory data also need to be integrated to support and interpret the observations. Interoperable software and interfaces have recently been developed in many scientific domains. The Virtual Observatory (VO) interoperable standards developed for Astronomy by the International Virtual Observatory Alliance (IVOA) can be adapted to Planetary Sciences, as demonstrated by the VESPA (Virtual European Solar and Planetary Access) team within the Europlanet-H2020-RI project. Other communities have developed their own standards: GIS (Geographic Information System) for Earth and planetary surfaces tools, SPASE (Space Physics Archive Search and Extract) for space plasma, PDS4 (NASA Planetary Data System, version 4) and IPDA (International Planetary Data Alliance) for planetary mission archives, etc, and an effort to make them interoperable altogether is starting, including automated workflows to process related data from different sources.

Plasma confinement in a magnetic field of the internal ring current

International Nuclear Information System (INIS)

Shafranov, Vitaly; Popovich, Paul; Samitov, Marat

2000-01-01

Plasma confinement in compact region surrounding an internal ring current is considered. As the limiting case of large aspect ratio system the cylindrical plasma is considered initially. Analysis of the cylindrical tubular plasma equilibrium and stability against the most dangerous flute (m=0) and kink (m=1) modes revealed the possibility of the MHD stable plasma confined by magnetic field of the internal rod current, with rather peaked plasma pressure and maximal local beta β(γ)=0.4. In case of the toroidal internal ring system an additional external magnetic field creates the boundary separatrix witch limits the plasma volume. The dependence of the plasma pressure profiles, marginally stable with respect to the flute modes, from the shape of the external plasma boundary (separatrix) in such kind closed toroidal systems is investigated. The internal ring system with circular poloidal magnetic mirror, where the ring supports could be placed, is proposed. (author)

Magnetic reversals from planetary dynamo waves.

Science.gov (United States)

Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

2016-11-24

A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

Second International Workshop on Magnetic Particle Imaging

CERN Document Server

Borgert, Jörn; Magnetic Particle Imaging : A Novel SPIO Nanoparticle Imaging Technique

2012-01-01

Magnetic Particle Imaging (MPI) is a novel imaging modality. In MPI superparamagnetic iron oxide nanoparticles are used as tracer materials. The volume is the proceeding of the 2nd international workshop on magnetic particle imaging (IWMPI). The workshop aims at covering the status and recent developments of both, the instrumentation and the tracer material, as each of them is equally important in designing a well performing MPI. For instance, the current state of the art in magnetic coil design for MPI is discussed. With a new symmetrical arrangement of coils, a field-free line (FFL) can be produced that promises a significantly higher sensitivity compared with the standard arrangement for a FFP. Furthermore, the workshop aims at presenting results from phantom and pre-clinical studies.

International program activities in magnetic fusion energy

International Nuclear Information System (INIS)

1986-03-01

The following areas of our international activities in magnetic fusion are briefly described: (1) policy; (2) background; (3) strategy; (4) strategic considerations and concerns; (5) domestic program inplications, and (6) implementation. The current US activities are reviewed. Some of our present program needs are outlined

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.

An international network of magnetic observatories

Science.gov (United States)

Love, Jeffrey J.; Chulliat, A.

2013-01-01

Since its formation in the late 1980s, the International Real-Time Magnetic Observatory Network (INTERMAGNET), a voluntary consortium of geophysical institutes from around the world, has promoted the operation of magnetic observatories according to modern standards [eg. Rasson, 2007]. INTERMAGNET institutes have cooperatively developed infrastructure for data exchange and management ads well as methods for data processing and checking. INTERMAGNET institute have also helped to expand global geomagnetic monitoring capacity, most notably by assisting magnetic observatory institutes in economically developing countries by working directly with local geophysicists. Today the INTERMAGNET consortium encompasses 57 institutes from 40 countries supporting 120 observatories (see Figures 1a and 1b). INTERMAGNET data record a wide variety of time series signals related to a host of different physical processes in the Earth's interiors and in the Earth's surrounding space environment [e.g., Love, 2008]. Observatory data have always had a diverse user community, and to meet evolving demand, INTERMAGNET has recently coordinated the introduction of several new data services.

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

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.

Magnetorheological measurements with consideration for the internal magnetic field in samples

Energy Technology Data Exchange (ETDEWEB)

Kordonski, W; Gorodkin, S [QED Technologies International, 1040 University Ave., Rochester, NY 14607 (United States)], E-mail: kordonski@qedmrf.com

2009-02-01

The magnetically induced yield stress in a sample of suspension of magnetic particles is associated with formation of a field-oriented structure, the strength of which depends on the degree of particles magnetization. This factor is largely defined by the actual magnetic field strength in the sample. At the same time it is common practice to present and analyze magnetorheological characteristics as a function of the applied magnetic field. Uncertainty of an influence function in magnetorheology hampers interpretation of data obtained with different measurement configurations. It was shown in this paper that rheological response of magnetorheological fluid to the applied magnetic field is defined by the sample's actual (internal) magnetic field intensity, which, in turn, depends on sample geometry and field orientation all other factors being equal. Utilization of the sample's actual field as an influence function in magnetorheology allows proper interpretation of data obtained with different measuring system configurations. Optimization of the actual internal field is a promising approach in designing of energy efficient magnetorheological devices.

Magnetic reversals from planetary dynamo waves

DEFF Research Database (Denmark)

Sheyko, Andrey; Finlay, Chris; Jackson, Andrew

2016-01-01

A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes ...... to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.......A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes...... place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines...

Considering the Ethical Implications of Space Exploration and Potential Impacts on Planetary Environments and Possible Indigenous Life

Science.gov (United States)

Race, Margaret

Since the early days of the Outer Space Treaty, a primary concern of planetary protection policy has been to avoid contamination of planetary environments by terrestrial microbes that could compromise current or subsequent scientific investigations, particularly those searching for indigenous life. Over the past decade robotic missions and astrobiological research have greatly increased our understanding of diverse planetary landscapes and altered our views about the survivability of terrestrial organisms in extreme environments. They have also expanded notions about the prospect for finding evidence of extraterrestrial life. Recently a number of different groups, including the COSPAR Planetary Protection Workshop in Montreal (January 2008), have questioned whether it is advisable to re-examine current biological planetary protection policy in light of the ethical implications and responsibilities to preserve planetary environments and possible indigenous life. This paper discusses the issues and concerns that have led to recent recommendations for convening an international workshop specifically to discuss planetary protection policy and practices within a broader ethical and practical framework, and to consider whether revisions to policy and practices should be made. In addition to including various international scientific and legal organizations and experts in such a workshop, it will be important to find ways to involve the public in these discussions about ethical aspects of planetary exploration.

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.

FENIX [Fusion ENgineering International eXperimental]: A test facility for ITER [International Thermonuclear Experimental Reactor] and other new superconducting magnets

International Nuclear Information System (INIS)

Slack, D.S.; Patrick, R.E.; Miller, J.R.

1990-01-01

The Fusion ENgineering International eXperimental (FENIX) Test Facility which is nearing completion at Lawrence Livermore National Laboratory, is a 76-t set of superconducting magnets housed in a 4-m-diameter cryostat. It represents a significant step toward meeting the testing needs for the development of superconductors appropriate for large-scale magnet applications such as the International Thermonuclear Experimental Reactor (ITER). The magnet set is configured to allow radial access to the 0.4-m-diameter high-field region where maximum fields up to 14 T will be provided. The facility is fitted with a thermally isolated test well with a port to the high-field region that allows insertion and removal of test conductors without disturbing the cryogenic environment of the magnets. It is expected that the facility will be made available to magnet developers internationally, and this paper discusses its general design features, its construction, and its capabilities

Estimating the Magnetic Field Strength in Hot Jupiters

Energy Technology Data Exchange (ETDEWEB)

Yadav, Rakesh K. [Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138 (United States); Thorngren, Daniel P., E-mail: rakesh_yadav@fas.harvard.edu [Department of Physics, University of California, Santa Cruz, CA (United States)

2017-11-01

A large fraction of known Jupiter-like exoplanets are inflated as compared to Jupiter. These “hot” Jupiters orbit close to their parent star and are bombarded with intense starlight. Many theories have been proposed to explain their radius inflation and several suggest that a small fraction of the incident starlight is injected into the planetary interior, which helps to puff up the planet. How will such energy injection affect the planetary dynamo? In this Letter, we estimate the surface magnetic field strength of hot Jupiters using scaling arguments that relate energy available in planetary interiors to the dynamo-generated magnetic fields. We find that if we take into account the energy injected in the planetary interior that is sufficient to inflate hot Jupiters to observed radii, then the resulting dynamo should be able generate magnetic fields that are more than an order of magnitude stronger than the Jovian values. Our analysis highlights the potential fundamental role of the stellar light in setting the field strength in hot Jupiters.

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.

Effective Induction Heating around Strongly Magnetized Stars

Science.gov (United States)

Kislyakova, K. G.; Fossati, L.; Johnstone, C. P.; Noack, L.; Lüftinger, T.; Zaitsev, V. V.; Lammer, H.

2018-05-01

Planets that are embedded in the changing magnetic fields of their host stars can experience significant induction heating in their interiors caused by the planet’s orbital motion. For induction heating to be substantial, the planetary orbit has to be inclined with respect to the stellar rotation and dipole axes. Using WX UMa, for which the rotation and magnetic axes are aligned, as an example, we show that for close-in planets on inclined orbits, induction heating can be stronger than the tidal heating occurring inside Jupiter’s satellite Io; namely, it can generate a surface heat flux exceeding 2 W m‑2. An internal heating source of such magnitude can lead to extreme volcanic activity on the planet’s surface, possibly also to internal local magma oceans, and to the formation of a plasma torus around the star aligned with the planetary orbit. A strongly volcanically active planet would eject into space mostly SO2, which would then dissociate into oxygen and sulphur atoms. Young planets would also eject CO2. Oxygen would therefore be the major component of the torus. If the O I column density of the torus exceeds ≈1012 cm‑2, the torus could be revealed by detecting absorption signatures at the position of the strong far-ultraviolet O I triplet at about 1304 Å. We estimate that this condition is satisfied if the O I atoms in the torus escape the system at a velocity smaller than 1–10 km s‑1. These estimates are valid also for a tidally heated planet.

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)

Development of transient internal probe (TIP) magnetic field diagnostic

International Nuclear Information System (INIS)

Galambos, J.P.; Bohnet, M.A.; Jarboe, T.R.; Mattick, A.T.

1994-01-01

The Transient Internal Probe (TIP) is designed to permit measurement of internal magnetic fields, in hot, high density plasmas. The concept consists of accelerating a probe to high velocities (2.2 Km/s) in order to minimize probe exposure time to plasma. Faraday rotation within the probe is used to measure the local magnetic field. An Argon laser illuminates the probe consisting of a Faraday-rotator material with a retro-reflector that returns the incident light to the detection system. Performance results of the light gas gun and optical detection system will be shown. To date, the gas gun has been extensively tested consistently achieving velocities between 2 and 3 km/s. The probe and detection scheme have been tested by dropping the probe through a static magnetic field. Magnetic field resolution of 20 gauss and spatial resolution of 5 mm has been achieved. System frequency response is 10Mhz. Work is currently being conducted to integrate the diagnostic system with laboratory plasma experiments. Specifically a gas interfaced system has been developed to prevent helium muzzle gas from entering the plasma chamber with the probe. Additionally the probe must be separated from the sabot which protects the probe during acceleration in the gas gun. Data will be presented showing the results of various separation techniques

Convection and magnetic field generation in the interior of planets (August Love Medal Lecture)

Science.gov (United States)

Christensen, U. R.

2009-04-01

Thermal convection driven by internal energy plays a role of paramount importance in planetary bodies. Its numerical modeling has been an essential tool for understanding how the internal engine of a planet works. Solid state convection in the silicate or icy mantles is the cause of endogenic tectonic activity, volcanism and, in the case of Earth, of plate motion. It also regulates the energy budget of the entire planet, including that of its core, and controls the presence or absence of a dynamo. The complex rheology of solid minerals, effects of phase transitions, and chemical heterogeneity are important issues in mantle convection. Examples discussed here are the convection pattern in Mars and the complex morphology of subducted slabs that are observed by seismic tomography in the Earth's mantle. Internally driven convection in the deep gas envelopes of the giant planets is possibly the cause for the strong jet streams at the surfaces that give rise to their banded appearance. Modeling of the magnetohydrodynamic flow in the conducting liquid core of the Earth has been remarkably successful in reproducing the primary properties of the geomagnetic field. As an examplefor attempts to explain also secondary properties, I will discuss dynamo models that account for the thermal coupling to the mantle. The understanding of the somewhat enigmatic magnetic fields of some other planets is less advanced. Here I will show that dynamos that operate below a stable conducting layer in the upper part of the planetary core can explain the unusual magnetic field properties of Mercury and Saturn. The question what determines the strength of a dynamo-generated magnetic field has been a matter of debate. From a large set of numerical dynamo simulations that cover a fair range of control parameters, we find a rule that relates magnetic field strength to the part of the energy flux that is thermodynamically available to be transformed into other forms of energy. This rules predicts

Properties of internal planetary-scale inertio gravity waves in the mesosphere

Directory of Open Access Journals (Sweden)

H. G. Mayr

2004-11-01

Full Text Available At high latitudes in the upper mesosphere, horizontal wind oscillations have been observed with periods around 10h. Waves with such a period are generated in our Numerical Spectral Model (NSM, and they are identified as planetary-scale inertio gravity waves (IGW. These IGWs have periods between 9 and 11h and appear above 60km in the zonal mean (m=0, as well as in m=1 to 4, propagating eastward and westward. Under the influence of the Coriolis force, the amplitudes of the waves propagating westward are larger at high latitudes than those propagating eastward. The waves grow in magnitude at least up to about 100km and have vertical wavelengths around 25km. Applying a running window of 15 days for spectral analysis, the amplitudes in the wind field are typically between 10 and 20m/s and can reach 30m/s in the westward propagating component for m=1 at the poles. In the temperature perturbations, the wave amplitudes above 100km are typically 5K and as large as 10K for m=0 at the poles. The IGWs are intermittent but reveal systematic seasonal variations, with the largest amplitudes occurring generally in late winter and spring. Numerical experiments show that such waves are also generated without excitation of the migrating tides. The amplitudes and periods then are similar, indicating that the tides are not essential to generate the waves. However, the seasonal variations without tides are significantly different, which leads to the conclusion that non linear interactions between the semidiurnal tide and planetary waves must contribute to the excitation of the IGWs. Directly or indirectly through the planetary waves, the IGWs are apparently excited by the instabilities that arise in the zonal mean circulation. When the solar heating is turned off for m=0, both the PWs and IGWs essentially disappear. That the IGWs and PWs have common roots in their excitation mechanism is also indicated by the striking similarity of their seasonal variations in the

Dications and thermal ions in planetary atmospheric escape

Science.gov (United States)

Lilensten, J.; Simon Wedlund, C.; Barthélémy, M.; Thissen, R.; Ehrenreich, D.; Gronoff, G.; Witasse, O.

2013-01-01

In the recent years, the presence of dications in the atmospheres of Mars, Venus, Earth and Titan has been modeled and assessed. These studies also suggested that these ions could participate to the escape of the planetary atmospheres because a large fraction of them is unstable and highly energetic. When they dissociate, their internal energy is transformed into kinetic energy which may be larger than the escape energy. The goal of this study is to assess the impact of the doubly-charged ions in the escape of CO2-dominated planetary atmospheres and to compare it to the escape of thermal photo-ions. We solve a Boltzmann transport equation at daytime taking into account the dissociative states of CO2++ for a simplified single constituent atmosphere of a case-study planet. We compute the escape of fast ions using a Beer-Lambert approach. We study three test-cases. On a Mars-analog planet in today's conditions, we retrieve the measured electron escape flux. When comparing the two mechanisms (i.e. excluding solar wind effects, sputtering, etc.), the escape due to the fast ions issuing from the dissociation of dications may account for up to 6% of the total and the escape of thermal ions for the remaining. We show that these two mechanisms cannot explain the escape of the atmosphere since the magnetic field vanished and even contribute only marginally to this loss. We show that with these two mechanisms, the atmosphere of a Mars analog planet would empty in another giga years and a half. At Venus orbit, the contribution of the dications in the escape rate is negligible. When simulating the hot Jupiter HD 209458 b, the two processes cannot explain the measured escape flux of C+. This study shows that the dications may constitute a source of the escape of planetary atmospheres which had not been taken into account until now. This source, although marginal, is not negligible. The influence of the photoionization is of course large, but cannot explain alone the loss of Mars

An Antarctic research outpost as a model for planetary exploration.

Science.gov (United States)

Andersen, D T; McKay, C P; Wharton, R A; Rummel, J D

1990-01-01

During the next 50 years, human civilization may well begin expanding into the solar system. This colonization of extraterrestrial bodies will most likely begin with the establishment of small research outposts on the Moon and/or Mars. In all probability these facilities, designed primarily for conducting exploration and basic science, will have international participation in their crews, logistical support and funding. High fidelity Earth-based simulations of planetary exploration could help prepare for these expensive and complex operations. Antarctica provides one possible venue for such a simulation. The hostile and remote dry valleys of southern Victoria Land offer a valid analog to the Martian environment but are sufficiently accessible to allow routine logistical support and to assure the relative safety of their inhabitants. An Antarctic research outpost designed as a planetary exploration simulation facility would have great potential as a testbed and training site for the operation of future Mars bases and represents a near-term, relatively low-cost alternative to other precursor activities. Antarctica already enjoys an international dimension, an aspect that is more than symbolically appropriate to an international endeavor of unprecedented scientific and social significance--planetary exploration by humans. Potential uses of such a facility include: 1) studying human factors in an isolated environment (including long-term interactions among an international crew); 2) testing emerging technologies (e.g., advanced life support facilities such as a partial bioregenerative life support system, advanced analytical and sample acquisition instrumentation and equipment, etc.); and 3) conducting basic scientific research similar to the research that will be conducted on Mars, while contributing to the planning for human exploration. (Research of this type is already ongoing in Antarctica).

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

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

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

Lunar and Planetary Geology

Science.gov (United States)

Basilevsky, Alexander T.

2018-05-01

Lunar and planetary geology can be described using examples such as the geology of Earth (as the reference case) and geologies of the Earth's satellite the Moon; the planets Mercury, Mars and Venus; the satellite of Saturn Enceladus; the small stony asteroid Eros; and the nucleus of the comet 67P Churyumov-Gerasimenko. Each body considered is illustrated by its global view, with information given as to its position in the solar system, size, surface, environment including gravity acceleration and properties of its atmosphere if it is present, typical landforms and processes forming them, materials composing these landforms, information on internal structure of the body, stages of its geologic evolution in the form of stratigraphic scale, and estimates of the absolute ages of the stratigraphic units. Information about one body may be applied to another body and this, in particular, has led to the discovery of the existence of heavy "meteoritic" bombardment in the early history of the solar system, which should also significantly affect Earth. It has been shown that volcanism and large-scale tectonics may have not only been an internal source of energy in the form of radiogenic decay of potassium, uranium and thorium, but also an external source in the form of gravity tugging caused by attractions of the neighboring bodies. The knowledge gained by lunar and planetary geology is important for planning and managing space missions and for the practical exploration of other bodies of the solar system and establishing manned outposts on them.

Internal Magnetic Configuration Measured by ECE Imaging on EAST Tokamak

International Nuclear Information System (INIS)

Xu Ming; Wen Yizhi; Xie Jinlin; Yu Changxuan; Gao Bingxi; Xu Xiaoyuan; Liu Wandong; Hu Liqun; Sun Youwen; Qian Jinping; Wan Baonian

2013-01-01

ECE imaging (electron cyclotron emission imaging) is an important diagnostic which can give 2D imaging of temperature fluctuation in the core of tokamak. A method based on ECE imaging is introduced which can give the information of the position of magnetic axis and the structure of internal magnetic surface for EAST tokamak. The EFIT equilibrium reconstruction is not reliable due to the absence of important core diagnostic at the initial phase for EAST, so the information given by ECE imaging could help to improve the accuracy of EFIT equilibrium reconstruction. (magnetically confined plasma)

A look at magnetic crack testing at an international level

International Nuclear Information System (INIS)

Deutsch, V.; Cost, H.; Schug, W.

1984-01-01

On an international level, there are several different magnetization processes in use for magnetic particle crack testing. Anglo-Saxon countries implement two separate working cycles with a DC current or field respectively. France has introduced combined sequential magnetization using a DC field. For German speaking countries, a combination of out-of-phase AC fields represents the state of the art. Comparisons present the advantages and disadvantages involved. Consequences arising from the equipment used are indicated by way of an example of a new generation of crack testing equipment. (orig.) [de

Internal magnetic turbulence measurement in plasma by cross polarization scattering

Energy Technology Data Exchange (ETDEWEB)

Zou, X L; Colas, L; Paume, M; Chareau, J M; Laurent, L; Devynck, P; Gresillon, D

1994-09-01

For the first time, the internal magnetic turbulence is measured by a new cross polarization scattering diagnostic in Tore Supra tokamak. The principle of this experiment is presented. It is based on the polarization change or mode conversion of the e.m. wave scattering by magnetic fluctuations. The role of different physical processes on the signal formation are investigated. From the Observation, a rough estimate for the relative magnetic fluctuations of about 10{sup -4} is obtained. A strong correlation of the measured signal with additional heating is observed. (author). 14 refs., 4 figs.

THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION MODELS OF HD 189733b AND HD 209458b WITH CONSISTENT MAGNETIC DRAG AND OHMIC DISSIPATION

International Nuclear Information System (INIS)

Rauscher, Emily; Menou, Kristen

2013-01-01

We present the first three-dimensional circulation models for extrasolar gas giant atmospheres with geometrically and energetically consistent treatments of magnetic drag and ohmic dissipation. Atmospheric resistivities are continuously updated and calculated directly from the flow structure, strongly coupling the magnetic effects with the circulation pattern. We model the hot Jupiters HD 189733b (T eq ≈ 1200 K) and HD 209458b (T eq ≈ 1500 K) and test planetary magnetic field strengths from 0 to 30 G. We find that even at B = 3 G the atmospheric structure and circulation of HD 209458b are strongly influenced by magnetic effects, while the cooler HD 189733b remains largely unaffected, even in the case of B = 30 G and super-solar metallicities. Our models of HD 209458b indicate that magnetic effects can substantially slow down atmospheric winds, change circulation and temperature patterns, and alter observable properties. These models establish that longitudinal and latitudinal hot spot offsets, day-night flux contrasts, and planetary radius inflation are interrelated diagnostics of the magnetic induction process occurring in the atmospheres of hot Jupiters and other similarly forced exoplanets. Most of the ohmic heating occurs high in the atmosphere and on the dayside of the planet, while the heating at depth is strongly dependent on the internal heat flux assumed for the planet, with more heating when the deep atmosphere is hot. We compare the ohmic power at depth in our models, and estimates of the ohmic dissipation in the bulk interior (from general scaling laws), to evolutionary models that constrain the amount of heating necessary to explain the inflated radius of HD 209458b. Our results suggest that deep ohmic heating can successfully inflate the radius of HD 209458b for planetary magnetic field strengths of B ≥ 3-10 G.

Mercury's magnetic field and interior

International Nuclear Information System (INIS)

Connerney, J.E.P.; Ness, N.F.

1988-01-01

The magnetic-field data collected on Mercury by the Mariner-10 spacecraft present substantial evidence for an intrinsic global magnetic field. However, studies of Mercury's thermal evolution show that it is most likely that the inner core region of Mercury solidified or froze early in the planet's history. Thus, the explanation of Mercury's magnetic field in the framework of the traditional planetary dynamo is less than certain

Magnetic domains and magnetic stability of cohenite from the Morasko iron meteorite

Energy Technology Data Exchange (ETDEWEB)

Reznik, B. [Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe (Germany); Kontny, A., E-mail: agnes.kontny@kit.edu [Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe (Germany); Uehara, M.; Gattacceca, J. [CNRS, Aix Marseille Univ, IRD, Coll France, CEREGE, Aix-en-Provence (France); Solheid, P.; Jackson, M. [Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN (United States)

2017-03-15

Magnetic properties, texture and microstructure of cohenite grains from Morasko iron meteorite have been investigated using electron backscattered diffraction, Bitter pattern technique, magneto-optical imaging method and magnetic force microscopy. Cohenite shows much stronger magnetic contrast compared to kamacite because it is magnetically harder than the Fe-Ni alloy, and thus causes higher stray fields. A surprising result is the high stability and reversibility of the global stripe-like magnetic domain structure in cohenite when applying high magnetic fields up to 1.5 T, and exposing it to high temperatures above the Curie temperature of about 220 °C. Heating up to 700 °C under atmosphere conditions has shown that cohenite remains stable and that the global magnetic domain structures mainly recover to its preheating state. This observation suggests that magnetic domains are strongly controlled by the crystal anisotropy of cohenite. Branching magnetic domain structures at the grain boundary to kamacite can be annealed, which indicates that they are very sensitive to record deformation. EBSD observations clearly demonstrate that increasing deviation from the easy [010] crystallographic axis and stress localization are the main factors controlling the distortion of Bitter patterns, and suggest a high sensitivity of the cohenite magnetic domain structure to local microstructural heterogeneities. The results of this study substantiate the theory that cohenite can be a good recorder of magnetic fields in planetary core material. - Highlights: • Magnetic domain structure of cohenite from the Morasko iron meteorite was investigated by Bitter pattern method, magneto-optical imaging and magnetic force microscopy. • Strong magnetocrystalline anisotropy explains high magnetic stability. • Magnetic domain structure shows high sensitivity to local microstructural heterogeneities. • Cohenite is probably a good recorder of magnetic fields in planetary core material.

Magnetic domains and magnetic stability of cohenite from the Morasko iron meteorite

International Nuclear Information System (INIS)

Reznik, B.; Kontny, A.; Uehara, M.; Gattacceca, J.; Solheid, P.; Jackson, M.

2017-01-01

Magnetic properties, texture and microstructure of cohenite grains from Morasko iron meteorite have been investigated using electron backscattered diffraction, Bitter pattern technique, magneto-optical imaging method and magnetic force microscopy. Cohenite shows much stronger magnetic contrast compared to kamacite because it is magnetically harder than the Fe-Ni alloy, and thus causes higher stray fields. A surprising result is the high stability and reversibility of the global stripe-like magnetic domain structure in cohenite when applying high magnetic fields up to 1.5 T, and exposing it to high temperatures above the Curie temperature of about 220 °C. Heating up to 700 °C under atmosphere conditions has shown that cohenite remains stable and that the global magnetic domain structures mainly recover to its preheating state. This observation suggests that magnetic domains are strongly controlled by the crystal anisotropy of cohenite. Branching magnetic domain structures at the grain boundary to kamacite can be annealed, which indicates that they are very sensitive to record deformation. EBSD observations clearly demonstrate that increasing deviation from the easy [010] crystallographic axis and stress localization are the main factors controlling the distortion of Bitter patterns, and suggest a high sensitivity of the cohenite magnetic domain structure to local microstructural heterogeneities. The results of this study substantiate the theory that cohenite can be a good recorder of magnetic fields in planetary core material. - Highlights: • Magnetic domain structure of cohenite from the Morasko iron meteorite was investigated by Bitter pattern method, magneto-optical imaging and magnetic force microscopy. • Strong magnetocrystalline anisotropy explains high magnetic stability. • Magnetic domain structure shows high sensitivity to local microstructural heterogeneities. • Cohenite is probably a good recorder of magnetic fields in planetary core material.

Exploring the planetary boundary for chemical pollution

DEFF Research Database (Denmark)

Diamond, Miriam L.; de Wit, Cynthia A.; Molander, Sverker

2015-01-01

Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience...... of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales......, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient...

LOW-MASS PLANETS IN PROTOPLANETARY DISKS WITH NET VERTICAL MAGNETIC FIELDS: THE PLANETARY WAKE AND GAP OPENING

Energy Technology Data Exchange (ETDEWEB)

Zhu Zhaohuan; Stone, James M.; Rafikov, Roman R., E-mail: zhzhu@astro.princeton.edu, E-mail: jstone@astro.princeton.edu, E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ, 08544 (United States)

2013-05-10

Some regions in protoplanetary disks are turbulent, while some regions are quiescent (e.g. the dead zone). In order to study how planets open gaps in both inviscid hydrodynamic disk (e.g. the dead zone) and the disk subject to magnetorotational instability (MRI), we carried out both shearing box two-dimensional inviscid hydrodynamical simulations and three-dimensional unstratified magnetohydrodynamical (MHD) simulations (having net vertical magnetic fields) with a planet at the box center. We found that, due to the nonlinear wave steepening, even a low mass planet can open gaps in both cases, in contradiction to the ''thermal criterion'' for gap opening. In order to understand if we can represent the MRI turbulent stress with the viscous {alpha} prescription for studying gap opening, we compare gap properties in MRI-turbulent disks to those in viscous HD disks having the same stress, and found that the same mass planet opens a significantly deeper and wider gap in net vertical flux MHD disks than in viscous HD disks. This difference arises due to the efficient magnetic field transport into the gap region in MRI disks, leading to a larger effective {alpha} within the gap. Thus, across the gap, the Maxwell stress profile is smoother than the gap density profile, and a deeper gap is needed for the Maxwell stress gradient to balance the planetary torque density. Comparison with previous results from net toroidal flux/zero flux MHD simulations indicates that the magnetic field geometry plays an important role in the gap opening process. We also found that long-lived density features (termed zonal flows) produced by the MRI can affect planet migration. Overall, our results suggest that gaps can be commonly produced by low mass planets in realistic protoplanetary disks, and caution the use of a constant {alpha}-viscosity to model gaps in protoplanetary disks.

LOW-MASS PLANETS IN PROTOPLANETARY DISKS WITH NET VERTICAL MAGNETIC FIELDS: THE PLANETARY WAKE AND GAP OPENING

International Nuclear Information System (INIS)

Zhu Zhaohuan; Stone, James M.; Rafikov, Roman R.

2013-01-01

Some regions in protoplanetary disks are turbulent, while some regions are quiescent (e.g. the dead zone). In order to study how planets open gaps in both inviscid hydrodynamic disk (e.g. the dead zone) and the disk subject to magnetorotational instability (MRI), we carried out both shearing box two-dimensional inviscid hydrodynamical simulations and three-dimensional unstratified magnetohydrodynamical (MHD) simulations (having net vertical magnetic fields) with a planet at the box center. We found that, due to the nonlinear wave steepening, even a low mass planet can open gaps in both cases, in contradiction to the ''thermal criterion'' for gap opening. In order to understand if we can represent the MRI turbulent stress with the viscous α prescription for studying gap opening, we compare gap properties in MRI-turbulent disks to those in viscous HD disks having the same stress, and found that the same mass planet opens a significantly deeper and wider gap in net vertical flux MHD disks than in viscous HD disks. This difference arises due to the efficient magnetic field transport into the gap region in MRI disks, leading to a larger effective α within the gap. Thus, across the gap, the Maxwell stress profile is smoother than the gap density profile, and a deeper gap is needed for the Maxwell stress gradient to balance the planetary torque density. Comparison with previous results from net toroidal flux/zero flux MHD simulations indicates that the magnetic field geometry plays an important role in the gap opening process. We also found that long-lived density features (termed zonal flows) produced by the MRI can affect planet migration. Overall, our results suggest that gaps can be commonly produced by low mass planets in realistic protoplanetary disks, and caution the use of a constant α-viscosity to model gaps in protoplanetary disks.

Magnetoresistivity and microstructure of YBa2Cu3Oy prepared using planetary ball milling

International Nuclear Information System (INIS)

Hamrita, A.; Ben Azzouz, F.; Madani, A.; Ben Salem, M.

2012-01-01

Superconducting properties of YBa 2 Cu 3 O y prepared using planetary ball milling were studied. Y-deficient YBa 2 Cu 3 O y nanoparticles are embedded in the superconducting matrix. Ball milled sample exhibits a large magnetoresistivity in weak magnetic fields at 77 K. We have studied the microstructure and the magnetoresistivity of polycrystalline YBa 2 Cu 3 O y (YBCO or Y-123 for brevity) embedded with nanoparticles of Y-deficient YBCO, generated by the planetary ball milling technique. Bulk samples were synthesized from a precursor YBCO powder, which was prepared from commercial high purity Y 2 O 3 , Ba 2 CO 3 and CuO via a one-step annealing process in air at 950 °C. After planetary ball milling of the precursor, the powder was uniaxially pressed and subsequently annealed at 950 °C in air. Phase analysis by X-ray diffraction (XRD), granular structure examination by scanning electron microscopy (SEM), microstructure investigation by transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDXS) were carried out. TEM analyses show that nanoparticles of Y-deficient YBCO, generated by ball milling, are embedded in the superconducting matrix. Electrical resistance as a function of temperature, ρ(T), revealed that the zero resistance temperature, T co , is 84.5 and 90 K for the milled and unmilled samples respectively. The milled ceramics exhibit a large magnetoresistance in weak magnetic fields at liquid nitrogen temperature. This attractive effect is of high significance as it makes these materials promising candidates for practical application in magnetic field sensor devices.

Density-functional theory for internal magnetic fields

Science.gov (United States)

Tellgren, Erik I.

2018-01-01

A density-functional theory is developed based on the Maxwell-Schrödinger equation with an internal magnetic field in addition to the external electromagnetic potentials. The basic variables of this theory are the electron density and the total magnetic field, which can equivalently be represented as a physical current density. Hence, the theory can be regarded as a physical current density-functional theory and an alternative to the paramagnetic current density-functional theory due to Vignale and Rasolt. The energy functional has strong enough convexity properties to allow a formulation that generalizes Lieb's convex analysis formulation of standard density-functional theory. Several variational principles as well as a Hohenberg-Kohn-like mapping between potentials and ground-state densities follow from the underlying convex structure. Moreover, the energy functional can be regarded as the result of a standard approximation technique (Moreau-Yosida regularization) applied to the conventional Schrödinger ground-state energy, which imposes limits on the maximum curvature of the energy (with respect to the magnetic field) and enables construction of a (Fréchet) differentiable universal density functional.

International magnetic pulse compression workshop: (Proceedings)

Energy Technology Data Exchange (ETDEWEB)

Kirbie, H.C.; Newton, M.A.; Siemens, P.D.

1991-04-01

A few individuals have tried to broaden the understanding of specific and salient pulsed-power topics. One such attempt is this documentation of a workshop on magnetic switching as it applies primarily to pulse compression (power transformation), affording a truly international perspective by its participants under the initiative and leadership of Hugh Kirbie and Mark Newton of the Lawrence Livermore National Laboratory (LLNL) and supported by other interested organizations. During the course of the Workshop at Granlibakken, a great deal of information was amassed and a keen insight into both the problems and opportunities as to the use of this switching approach was developed. The segmented workshop format proved ideal for identifying key aspects affecting optimum performance in a variety of applications. Individual groups of experts addressed network and system modeling, magnetic materials, power conditioning, core cooling and dielectrics, and finally circuits and application. At the end, they came together to consolidate their input and formulate the workshop's conclusions, identifying roadblocks or suggesting research projects, particularly as they apply to magnetic switching's trump card--its high-average-power-handling capability (at least on a burst-mode basis). The workshop was especially productive both in the quality and quantity of information transfer in an environment conducive to a free and open exchange of ideas. We will not delve into the organization proper of this meeting, rather we wish to commend to the interested reader this volume, which provides the definitive and most up-to-date compilation on the subject of magnetic pulse compression from underlying principles to current state of the art as well as the prognosis for the future of magnetic pulse compression as a consensus of the workshop's organizers and participants.

International magnetic pulse compression workshop: [Proceedings

International Nuclear Information System (INIS)

Kirbie, H.C.; Newton, M.A.; Siemens, P.D.

1991-04-01

A few individuals have tried to broaden the understanding of specific and salient pulsed-power topics. One such attempt is this documentation of a workshop on magnetic switching as it applies primarily to pulse compression (power transformation), affording a truly international perspective by its participants under the initiative and leadership of Hugh Kirbie and Mark Newton of the Lawrence Livermore National Laboratory (LLNL) and supported by other interested organizations. During the course of the Workshop at Granlibakken, a great deal of information was amassed and a keen insight into both the problems and opportunities as to the use of this switching approach was developed. The segmented workshop format proved ideal for identifying key aspects affecting optimum performance in a variety of applications. Individual groups of experts addressed network and system modeling, magnetic materials, power conditioning, core cooling and dielectrics, and finally circuits and application. At the end, they came together to consolidate their input and formulate the workshop's conclusions, identifying roadblocks or suggesting research projects, particularly as they apply to magnetic switching's trump card--its high-average-power-handling capability (at least on a burst-mode basis). The workshop was especially productive both in the quality and quantity of information transfer in an environment conducive to a free and open exchange of ideas. We will not delve into the organization proper of this meeting, rather we wish to commend to the interested reader this volume, which provides the definitive and most up-to-date compilation on the subject of magnetic pulse compression from underlying principles to current state of the art as well as the prognosis for the future of magnetic pulse compression as a consensus of the workshop's organizers and participants

A high-resolution Fourier Transform Spectrometer for planetary spectroscopy

Science.gov (United States)

Cruikshank, D. P.; Sinton, W. M.

1973-01-01

The employment of a high-resolution Fourier Transform Spectrometer (FTS) is described for planetary and other astronomical spectroscopy in conjunction with the 88-inch telescope at Mauna Kea Observatory. The FTS system is designed for a broad range of uses, including double-beam laboratory spectroscopy, infrared gas chromatography, and nuclear magnetic resonance spectroscopy. The data system is well-suited to astronomical applications because of its great speed in acquiring and transforming data, and because of the enormous storage capability of the magnetic tape unit supplied with the system. The basic instrument is outlined 2nd some of the initial results from the first attempted use on the Mauna Kea 88-inch telescope are reported.

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.

Change of Surface Roughness and Planetary Boundary Layer

DEFF Research Database (Denmark)

Jensen, Niels Otto

1978-01-01

The ratio between upstream and far downstream surface friction velocities relative to a change in surface roughness is given on the basis of results from surface Rossby number similarity theory. By simple theories for the internal boundary layer, which are found to compare quite well with recent...... numerical results from higher-order closure models, it is found that, even at a downwind distance such that the internal boundary layer has grown to the full height of the planetary boundary layers, the surface stress still considerably exceeds the equilibrium value...

Planetary science education in a multidisciplinar environment: an alternative approach for ISU

Science.gov (United States)

Calzada, A.

2012-09-01

The aim of the International Space University (ISU) located in Strasbourg, France, is to provide to the participants of its programs an overview of all the aspects of the space field. This also includes a basic background on Planetary Sciences. During the Master 2012 an individual project about impact processes was done. During this project some issues regarding planetary science awareness arise and it brought to the table the need to increase its presence in the ISU programs. The conclusions may be extrapolated to other academic institutions.

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

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.

Magnetic fields in the solar system planets, moons and solar wind interactions

CERN Document Server

Wicht, Johannes; Gilder, Stuart; Holschneider, Matthias

2018-01-01

This book addresses and reviews many of the still little understood questions related to the processes underlying planetary magnetic fields and their interaction with the solar wind. With focus on research carried out within the German Priority Program ”PlanetMag”, it also provides an overview of the most recent research in the field. Magnetic fields play an important role in making a planet habitable by protecting the environment from the solar wind. Without the geomagnetic field, for example, life on Earth as we know it would not be possible. And results from recent space missions to Mars and Venus strongly indicate that planetary magnetic fields play a vital role in preventing atmospheric erosion by the solar wind. However, very little is known about the underlying interaction between the solar wind and a planet’s magnetic field. The book takes a synergistic interdisciplinary approach that combines newly developed tools for data acquisition and analysis, computer simulations of planetary interiors an...

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

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.)

MAVEN Observations of Escaping Planetary Ions from the Martian Atmosphere: Mass, Velocity, and Spatial Distributions

Science.gov (United States)

Dong, Yaxue; Fang, Xiaohua; Brain, D. A.; McFadden, James P.; Halekas, Jasper; Connerney, Jack

2015-04-01

The Mars-solar wind interaction accelerates and transports planetary ions away from the Martian atmosphere through a number of processes, including ‘pick-up’ by electromagnetic fields. The MAVEN spacecraft has made routine observations of escaping planetary ions since its arrival at Mars in September 2014. The SupraThermal And Thermal Ion Composition (STATIC) instrument measures the ion energy, mass, and angular spectra. It has detected energetic planetary ions during most of the spacecraft orbits, which are attributed to the pick-up process. We found significant variations in the escaping ion mass and velocity distributions from the STATIC data, which can be explained by factors such as varying solar wind conditions, contributions of particles from different source locations and different phases during the pick-up process. We also study the spatial distributions of different planetary ion species, which can provide insight into the physics of ion escaping process and enhance our understanding of atmospheric erosion by the solar wind. Our results will be further interpreted within the context of the upstream solar wind conditions measured by the MAVEN Solar Wind Ion Analyzer (SWIA) instrument and the magnetic field environment measured by the Magnetometer (MAG) instrument. Our study shows that the ion spatial distribution in the Mars-Sun-Electric-Field (MSE) coordinate system and the velocity space distribution with respect to the local magnetic field line can be used to distinguish the ions escaping through the polar plume and those through the tail region. The contribution of the polar plume ion escape to the total escape rate will also be discussed.

Magnetic field of Mercury

International Nuclear Information System (INIS)

Jackson, D.J.; Beard, D.B.

1977-01-01

The geomagnetic field, suitably scaled down and parameterized, is shown to give a very good fit to the magnetic field measurements taken on the first and third passes of the Mariner 10 space probe past Mercury. The excellence of the fit to a reliable planetary magnetospheric model is good evidence that the Mercury magnetosphere is formed by a simple, permanent, intrinsic planetary magnetic field distorted by the effects of the solar wind. The parameters used for a best fit to all the data are (depending slightly on the choice of data) 2.44--2.55 for the ratio of Mercury's magnetic field strength at the subsolar point to that of the earth's subsolar point field (this results in a dipole moment of 170 γR/sub M/ 3 (R/sub M/ is Mercury Radius), i.e., 2.41 x 10 22 G cm 3 in the same direction as the earth's dipole), approx.-113 γR/sub M/ 4 for the planetary quadrupole moment parallel to the dipole moment, 10degree--17degree for the tilt of the planet dipole toward the sun, 4.5degree for the tilt of the dipole toward dawn, and 2.5degree--7.6degree aberration angle for the shift in the tail axis from the planet-sun direction because of the planet's orbital velocity. The rms deviation overall for the entire data set compared with the theoretical fitted model for the magnetic field strength was 17 γ (approx.4% of the maximum field measured). If the data from the first pass that show presumed strong time variations are excluded, the overall rms deviation for the field magnitude is only 10 γ

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

The fluxgate magnetometer of the BepiColombo Mercury Planetary Orbiter

Science.gov (United States)

Glassmeier, K.-H.; Auster, H.-U.; Heyner, D.; Okrafka, K.; Carr, C.; Berghofer, G.; Anderson, B. J.; Balogh, A.; Baumjohann, W.; Cargill, P.; Christensen, U.; Delva, M.; Dougherty, M.; Fornaçon, K.-H.; Horbury, T. S.; Lucek, E. A.; Magnes, W.; Mandea, M.; Matsuoka, A.; Matsushima, M.; Motschmann, U.; Nakamura, R.; Narita, Y.; O'Brien, H.; Richter, I.; Schwingenschuh, K.; Shibuya, H.; Slavin, J. A.; Sotin, C.; Stoll, B.; Tsunakawa, H.; Vennerstrom, S.; Vogt, J.; Zhang, T.

2010-01-01

The magnetometer (MAG) on the Mercury Planetary Orbiter (MPO) of the joint European-Japanese BepiColombo mission to planet Mercury is a low-noise, tri-axial, dual-sensor, digital fluxgate instrument with its sensors mounted on a 2.8-m-long boom. The primary MPO/MAG science objectives are to determine the spatial and temporal structure of the magnetic field in the Hermean system, in particular the structure and origin of the intrinsic magnetic field of Mercury. MPO/MAG has a dynamic measurement range of ±2000nT with a resolution of 2 pT during operation along the near-polar orbit of the MPO spacecraft around Mercury. MPO/MAG is designed to provide measurements with rates between 0.5 and 128 vectors/s. In cooperation with its sister magnetometer instrument, MMO/MGF on board the BepiColombo Mercury Magnetospheric Orbiter (MMO), MPO/MAG will be able to distinguish between temporal and spatial magnetic field variations in the magnetically closely coupled Hermean system.

PREDICTING THE CONFIGURATION OF A PLANETARY SYSTEM: KOI-152 OBSERVED BY KEPLER

International Nuclear Information System (INIS)

Wang Su; Ji Jianghui; Zhou Jilin

2012-01-01

The recent Kepler discovery of KOI-152 reveals a system of three hot super-Earth candidates that are in or near a 4:2:1 mean motion resonance. It is unlikely that they formed in situ; the planets probably underwent orbital migration during the formation and evolution process. The small semimajor axes of the three planets suggest that migration stopped at the inner edge of the primordial gas disk. In this paper, we focus on the influence of migration halting mechanisms, including migration 'dead zones', and inner truncation by the stellar magnetic field. We show that the stellar accretion rate, stellar magnetic field, and the speed of migration in the protoplanetary disk are the main factors affecting the final configuration of KOI-152. Our simulations suggest that three planets may be around a star with low star accretion rate or with high magnetic field. On the other hand, slow type I migration, which decreases to one-tenth of the linear analysis results, favors forming the configuration of KOI-152. Under such a formation scenario, the planets in the system are not massive enough to open gaps in the gas disk. The upper limits of the planetary masses are estimated to be about 15, 19, and 24 M ⊕ , respectively. Our results are also indicative of the near Laplacian configurations that are quite common in planetary systems.

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

-to-date with versions 3 and 4 of the PDS standards, as PDS4 will be used for ESA's ExoMars and upcoming BepiColombo missions. Users will have direct access to documentation, information and tools that are relevant to the scientific use of the dataset, including ancillary datasets, Software Interface Specification (SIS) documents, and any tools/help that the PSA team can provide. The new PSA interface was released in January 2017. The home page provides a direct and simple access to the scientific data, aiming to help scientists to discover and explore its content. The archive can be explored through a set of parameters that allow the selection of products through space and time. Quick views provide information needed for the selection of appropriate scientific products. During 2017, the PSA team will focus their efforts on developing a map search interface using GIS technologies to display ESA planetary datasets, an image gallery providing navigation through images to explore the datasets, and interoperability with international partners. This will be done in parallel with additional metadata searchable through the interface (i.e., geometry), and with a dedication to improve the content of 20 years of space exploration.

The effect of internal magnetic structure on the fishbone instability

International Nuclear Information System (INIS)

Roberts, D.W.; Powell, E.; Kaita, R.; Bell, R.; Chance, M.; Hatcher, R.; Holland, A.; Kaye, S.; Kessel, C.; Kugel, H.; LeBlanc, B.; Manickam, J.; Okabayashi, M.; Paul, S.; Pomphrey, N.; Sauthoff, N.; Sesnic, S.; Takahashi, H.; White, R.; Asakura, N.; Duperrex, P.; Gammel, G.

1992-01-01

Plasmas exhibiting the ''fishbone'' instability studied on the PBX-M tokamak show a distinct relationship between the plasma shape, the internal magnetic structure, and the presence or absence of fast ion losses associated with the fishbone mode. We have, for the first time, carried out measurements of the magnetic safety factor profile in fishbone-unstable plasmas, and used the knowledge of the associated experimental equilibria to compare the stability and fast ion loss properties of these plasmas with experimental observations

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

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

The Earth’s Magnetic Field in the Space Age

DEFF Research Database (Denmark)

Hulot, Gauthier; Balogh, André; Christensen, Ulrich R.

2010-01-01

. Focussing on the (still very broad) topic of Terrestrial Magnetism, this workshop was the last of a series of three that aimed to present, discuss and summarize recent advances in our understanding of magnetic fields in the solar system. The earlier workshops, on solar and on planetary magnetism, were held...

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.

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...

Planetary Missions of the 20th Century*

Science.gov (United States)

Moroz, V. I.; Huntress, W. T.; Shevalev, I. L.

2002-09-01

Among of the highlights of the 20th century were flights of spacecraft to other bodies of the Solar System. This paper describes briefly the missions attempted, their goals, and fate. Information is presented in five tables on the missions launched, their goals, mission designations, dates, discoveries when successful, and what happened if they failed. More detailed explanations are given in the accompanying text. It is shown how this enterprise developed and evolved step by step from a politically driven competition to intense scientific investigations and international cooperation. Initially, only the USA and USSR sent missions to the Moon and planets. Europe and Japan joined later. The USSR carried out significant research in Solar System exploration until the end of the 1980s. The Russian Federation no longer supports robotic planetary exploration for economic reasons, and it remains to be seen whether the invaluable Russian experience in planetary space flight will be lost. Collaboration between Russian and other national space agencies may be a solution.

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.

Scaling properties of planetary calderas and terrestrial volcanic eruptions

Directory of Open Access Journals (Sweden)

L. Sanchez

2012-11-01

Full Text Available Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.

Obtaining Magnetic Properties of Meteorites Using Magnetic Scanner

Science.gov (United States)

Kletetschka, G.; Nabelek, L.; Mazanec, M.; Simon, K.; Hruba, J.

2015-12-01

Magnetic images of Murchison meteorite's and Chelyabinsk meteorite's thin section have been obtained from magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10-3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses (Nabelek et al., 2015). Nabelek, L., Mazanec, M., Kdyr, S., and Kletetschka, G., 2015, Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section: Meteoritics & Planetary Science.

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.

Nasa's International Space Station: A Testbed for Planetary Protection Protocol Development

Science.gov (United States)

Bell, M. S.; Rucker, M.; Love, S.; Johnson, J.; Chambliss, J.; Pierson, D.; Ott, M.; Mary, N.; Glass, B.; Lupisella, M.;

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

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.

Internal magnetic probe measurements of MHD activity and current profiles in a tokamak

International Nuclear Information System (INIS)

Giannone, L.; Cross, R.C.

1987-01-01

Mirnov oscillations and plasma disruptions in the TORTUS tokamak have been studied by using both internal and external magnetic probe arrays. The internal probe was also used to measure the plasma current distribution so that results could be compared with resistive tearing mode calculations. The growth of m = 3, 4 and 5 modes was found to be consistent with linear tearing mode theory before a disruption but not after it. The observed mode amplitudes, typically b θ /B θ ∼ 5%, were much larger than theoretical estimates based on the magnetic energy available to drive the modes. Despite the presence of large islands near the limiter, most of the disruptions observed were associated with rapid growth of internal modes. (author). 23 refs, 14 figs

Internal magnetic probe measurements of MHD activity and current profiles in a tokamak

Energy Technology Data Exchange (ETDEWEB)

Giannone, L.; Cross, R C; Hutchinson, I H

1987-01-01

Mirnov oscillations and plasma disruptions in the TORTUS tokamak have been studied by using both internal and external magnetic probe arrays. The internal probe was also used to measure the plasma current distribution so that results could be compared with resistive tearing mode calculations. The growth of m = 3, 4 and 5 modes was found to be consistent with linear tearing mode theory before a disruption but not after it. The observed mode amplitudes, typically b/sub theta//B/sub theta/ approx. 5%, were much larger than theoretical estimates based on the magnetic energy available to drive the modes. Despite the presence of large islands near the limiter, most of the disruptions observed were associated with rapid growth of internal modes. (author). 23 refs, 14 figs.

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.

Studies in matter antimatter separation and in the origin of lunar magnetism

Science.gov (United States)

Barker, W. A.; Greeley, R.; Parkin, C.; Aggarwal, H.; Schultz, P.

1975-01-01

A progress report, covering lunar and planetary research is introduced. Data cover lunar ionospheric models, lunar and planetary geology, and lunar magnetism. Wind tunnel simulations of Mars aeolian problems and a comparative study of basaltic analogs of Lunar and Martial volcanic features was discussed.

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

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

Measurement of the internal magnetic fluctuation by the transport of runaways on J-TEXT

Energy Technology Data Exchange (ETDEWEB)

Chen, Z. Y., E-mail: zychen@hust.edu.cn; Huang, D. W.; Tong, R. H.; Yan, W.; Wei, Y. N.; Ma, T. K.; Jiang, Z. H.; Zhang, X. Q.; Chen, Z. P.; Yang, Z. J.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2016-11-15

The measurement of internal magnetic fluctuation is important for the study of transport in tokamak plasmas. The runaway electron transport induced by the sawtooth crash can be used to obtain the internal magnetic fluctuation. Inversed sawtooth-like activities on hard x-ray (HXR) fluxes following sawtooth activities were observed after the application of electrode biasing on J-TEXT tokamak. The runaway diffusion coefficient D{sub r} is deduced to be about 30 m{sup 2}/s according to the time delay of HXR flux peaks to the sawtooth crashes. The averaged value of normalized magnetic fluctuation in the discharges with electrode biasing was increased to the order of 1 × 10{sup −4}.

Planet gaps in the dust layer of 3D proto-planetary disks: Observability with ALMA

OpenAIRE

Gonzalez, Jean-François; Pinte, Christophe; Maddison, Sarah T.; Ménard, François

2013-01-01

2 pages, 2 figures, to appear in the Proceedings of IAU Symp. 299: Exploring the Formation and Evolution of Planetary Systems (Victoria, Canada); International audience; Among the numerous known extrasolar planets, only a handful have been imaged directly so far, at large orbital radii and in rather evolved systems. The Atacama Large Millimeter/submillimeter Array (ALMA) will have the capacity to observe these wide planetary systems at a younger age, thus bringing a better understanding of th...

Measurement of local, internal magnetic fluctuations via cross-polarization scattering in the DIII-D tokamak (invited)

Energy Technology Data Exchange (ETDEWEB)

Barada, K., E-mail: kshitish@ucla.edu; Rhodes, T. L.; Crocker, N. A.; Peebles, W. A. [University of California-Los Angeles, P.O. Box 957099, Los Angeles, California 90095 (United States)

2016-11-15

We present new measurements of internal magnetic fluctuations obtained with a novel eight channel cross polarization scattering (CPS) system installed on the DIII-D tokamak. Measurements of internal, localized magnetic fluctuations provide a window on an important physics quantity that we heretofore have had little information on. Importantly, these measurements provide a new ability to challenge and test linear and nonlinear simulations and basic theory. The CPS method, based upon the scattering of an incident microwave beam into the opposite polarization by magnetic fluctuations, has been significantly extended and improved over the method as originally developed on the Tore Supra tokamak. A new scattering geometry, provided by a unique probe beam, is utilized to improve the spatial localization and wavenumber range. Remotely controllable polarizer and mirror angles allow polarization matching and wavenumber selection for a range of plasma conditions. The quasi-optical system design, its advantages and challenges, as well as important physics validation tests are presented and discussed. Effect of plasma beta (ratio of kinetic to magnetic pressure) on both density and magnetic fluctuations is studied and it is observed that internal magnetic fluctuations increase with beta. During certain quiescent high confinement operational regimes, coherent low frequency modes not detected by magnetic probes are detected locally by CPS diagnostics.

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

NASA's Solar System Treks: Online Portals for Planetary Mapping and Modeling

Science.gov (United States)

Day, Brian

2017-01-01

NASA's Solar System Treks are a suite of web-based of lunar and planetary mapping and modeling portals providing interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to access mapped lunar data products from past and current missions for the Moon, Mars, Vesta, and more. New portals for additional planetary bodies are being planned. This presentation will recap significant enhancements to these toolsets during the past year and look ahead to future features and releases. Moon Trek is a new portal replacing its predecessor, the Lunar Mapping and Modeling Portal (LMMP), that significantly upgrades and builds upon the capabilities of LMMP. It features greatly improved navigation, 3D visualization, fly-overs, performance, and reliability. Additional data products and tools continue to be added. These include both generalized products as well as polar data products specifically targeting potential sites for NASA's Resource Prospector mission as well as for missions being planned by NASA's international partners. The latest release of Mars Trek includes new tools and data products requested by NASA's Planetary Science Division to support site selection and analysis for Mars Human Landing Exploration Zone Sites. Also being given very high priority by NASA Headquarters is Mars Trek's use as a means to directly involve the public in 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. Phobos Trek, the latest effort in the Solar System Treks suite, is being developed in coordination with the International Phobos/Deimos Landing Site Working Group, with landing site selection and analysis for JAXA's MMX (Martian Moons eXploration) mission as a primary driver.

NASA's Solar System Treks: Online Portals for Planetary Mapping and Modeling

Science.gov (United States)

Day, B. H.; Law, E.

2017-12-01

NASA's Solar System Treks are a suite of web-based of lunar and planetary mapping and modeling portals providing interactive visualization and analysis tools enabling mission planners, planetary scientists, students, and the general public to access mapped lunar data products from past and current missions for the Moon, Mars, Vesta, and more. New portals for additional planetary bodies are being planned. This presentation will recap significant enhancements to these toolsets during the past year and look ahead to future features and releases. Moon Trek is a new portal replacing its predecessor, the Lunar Mapping and Modeling Portal (LMMP), that significantly upgrades and builds upon the capabilities of LMMP. It features greatly improved navigation, 3D visualization, fly-overs, performance, and reliability. Additional data products and tools continue to be added. These include both generalized products as well as polar data products specifically targeting potential sites for NASA's Resource Prospector mission as well as for missions being planned by NASA's international partners. The latest release of Mars Trek includes new tools and data products requested by NASA's Planetary Science Division to support site selection and analysis for Mars Human Landing Exploration Zone Sites. Also being given very high priority by NASA Headquarters is Mars Trek's use as a means to directly involve the public in 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. Phobos Trek, the latest effort in the Solar System Treks suite, is being developed in coordination with the International Phobos/Deimos Landing Site Working Group, with landing site selection and analysis for JAXA's MMX mission as a primary driver.

Fundamental relations of mineral specific magnetic carriers for paleointensity determination

Czech Academy of Sciences Publication Activity Database

Kletetschka, Günther; Wieczorek, M. A.

2017-01-01

Roč. 272, November 2017 (2017), s. 44-49 ISSN 0031-9201 Institutional support: RVO:67985831 Keywords : Paleofield determination * TRM * Planetary magnetic anomalies * Néel’s theory of magnetism * Magnetic acquisition * Moon * Mars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Particles and field physics Impact factor: 2.075, year: 2016

Cosmic rays and ancient planetary magnetic fields

International Nuclear Information System (INIS)

Wesson, P.S.

1977-01-01

The possibility is discussed of using the latitude-dependent cutoff in the intensity and flux of cosmic ray particles reaching the surface of a planet to investigate ancient magnetic fields in the Moon, Mars and the Earth. In the last case, the method could provide a validity test for conventional palaeomagnetism. (Auth.)

A New Model of Jupiter's Magnetic Field from Juno's First Nine Orbits

DEFF Research Database (Denmark)

Connerney, J. E. P.; Kotsiaros, S.; Oliversen, R. J.

2018-01-01

A spherical harmonic model of the magnetic field of Jupiter is obtained from vector magnetic field observations acquired by the Juno spacecraft during its first nine polar orbits about the planet. Observations acquired during eight of these orbits provide the first truly global coverage of Jupiter......'s magnetic field with a coarse longitudinal separation of ~45° between perijoves. The magnetic field is represented with a degree 20 spherical harmonic model for the planetary (“internal”) field, combined with a simple model of the magnetodisc for the field (“external”) due to distributed magnetospheric...... currents. Partial solution of the underdetermined inverse problem using generalized inverse techniques yields a model (“Juno Reference Model through Perijove 9”) of the planetary magnetic field with spherical harmonic coefficients well determined through degree and order 10, providing the first detailed...

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

Benefits of rotational ground motions for planetary seismology

Science.gov (United States)

Donner, S.; Joshi, R.; Hadziioannou, C.; Nunn, C.; van Driel, M.; Schmelzbach, C.; Wassermann, J. M.; Igel, H.

2017-12-01

Exploring the internal structure of planetary objects is fundamental to understand the evolution of our solar system. In contrast to Earth, planetary seismology is hampered by the limited number of stations available, often just a single one. Classic seismology is based on the measurement of three components of translational ground motion. Its methods are mainly developed for a larger number of available stations. Therefore, the application of classical seismological methods to other planets is very limited. Here, we show that the additional measurement of three components of rotational ground motion could substantially improve the situation. From sparse or single station networks measuring translational and rotational ground motions it is possible to obtain additional information on structure and source. This includes direct information on local subsurface seismic velocities, separation of seismic phases, propagation direction of seismic energy, crustal scattering properties, as well as moment tensor source parameters for regional sources. The potential of this methodology will be highlighted through synthetic forward and inverse modeling experiments.

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

Magnetic Topology and Ion Outflow in Mars' Magnetotail

Science.gov (United States)

Mitchell, D. L.; Xu, S.; McFadden, J. P.; Hara, T.; Luhmann, J. G.; Mazelle, C. X.; Andersson, L.; DiBraccio, G. A.; Connerney, J. E. P.

2017-12-01

Planetary ion outflow down the Martian magnetotail could be an important atmospheric loss mechanism. This process depends on magnetic connectivity to the day-side ionosphere and on acceleration of ions to escape velocity. The Mars Atmosphere and Volatile Evolution (MAVEN) mission has obtained comprehensive ion, electron, and magnetic field data in Mars' magnetotail. The spacecraft is in a 75°-inclination, elliptical orbit that samples altitudes from 150 to 6200 km. As the orbit precesses, it sweeps through the tail at a variety of altitudes in this range. Data from the Solar Wind Electron Analyzer (SWEA) and Magnetometer (MAG) are used to determine the magnetic field topology in the tail at high cadence (every 2-4 seconds), and in particular whether field lines are open, closed, or draped, and if open whether they have access to the day-side or night-side ionosphere. Simultaneous observations by the Supra-Thermal and Thermal Ion Composition (STATIC) instrument and the Langmuir Probe and Waves (LPW) experiment are used to measure the density, composition, and velocity of planetary plasma on these field lines. We find that magnetic topology in the tail is complex and variable, and is influenced by the IMF polarity and the orientation of Mars' crustal magnetic fields with respect to the Sun. We find that planetary ion outflow occurs on both open and draped field lines. On open field lines, outflow tends to occur parallel to the field line, with colder, denser, and slower outflow on field lines connected to the day-side ionosphere (Fig. 1). On these same field lines (after correction for the spacecraft potential) a shift in the position of the He-II photoelectron feature indicates a 1-Volt parallel electric potential directed away from the planet. Except for H+ and occasionally O+, this potential is insufficient by itself to accelerate planetary ions to escape velocity. Outflow is warmer, less dense, and faster moving on draped field lines. In this case, the ion bulk

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

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

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

PREFACE: 8th International Conference on Fine Particle Magnetism (ICFPM2013)

Science.gov (United States)

2014-06-01

The 8th International Conference on Fine Particle Magnetism (ICFPM) was held in Perpignan from 24 to 27 June 2013, and was the continuation of the previous meetings held in Bangor (1996), Rome (1991), Barcelona (1999), Pittsburg (2002), London (2004), Rome (2007) and Uppsala (2010). The next meeting will be organized by Profs. Robert D. Shull, George Hadjipanayis and Cindi Dennis, in 2016 at NIST, Gaithersburg (USA). ICFPM is a small-sized conference focused on the magnetism of nanoparticles. It provides an international forum for discussing the state-of-the-art understanding of physics of these systems, of their properties and the underlying phenomena, as approached from a variety of directions: theory and modelling, experiments on well characterized or model systems (both fabricated and synthetised), as well as experiments on technologically-relevant non-ideal systems. This meeting brought together about 120 participants working on experimental, theoretical and applied topics of the multidisciplinary research areas covered by magnetic nanoparticles, with focused interest on either single-particle or collective phenomena. The technical program of the conference was based on keynote conferences, invited talks, oral contributions and poster sessions, covering the following aspects: . Fabrication, synthesis, characterization . Single particle, surface and finite-size effects on magnetic properties . Magnetization dynamics, micro-wave assisted switching, dynamical coupling . Assemblies, collective effects, self-assembling and nanostructuring . Applications : hyperthermia, drug delivery, magneto-caloric, magneto-resistance, magneto-plasmonics, magnetic particle imaging This ICFPM edition was organized by the group Nanoscale Spin Systems of the laboratory PROMES of the CNRS (UPR8521), and Université de Perpignan Via Domitia. The meeting took place at the Congress Center of the city of Perpignan providing high-quality facilities for the technical program as well for the

Modelling of charged satellite motion in Earth's gravitational and magnetic fields

Science.gov (United States)

Abd El-Bar, S. E.; Abd El-Salam, F. A.

2018-05-01

In this work Lagrange's planetary equations for a charged satellite subjected to the Earth's gravitational and magnetic force fields are solved. The Earth's gravity, and magnetic and electric force components are obtained and expressed in terms of orbital elements. The variational equations of orbit with the considered model in Keplerian elements are derived. The solution of the problem in a fully analytical way is obtained. The temporal rate of changes of the orbital elements of the spacecraft are integrated via Lagrange's planetary equations and integrals of the normalized Keplerian motion obtained by Ahmed (Astron. J. 107(5):1900, 1994).

How to bring absolute sustainability into decision-making: An industry case study using a Planetary Boundary-based methodology

DEFF Research Database (Denmark)

Ryberg, Morten W.; Owsianiak, Mikołaj; Clavreul, Julie

2018-01-01

The Planetary Boundaries concept has emerged as a framework for articulating environmental limits, gaining traction as a basis for considering sustainability in business settings, government policy and international guidelines. There is emerging interest in using the Planetary Boundaries concept...... as part of life cycle assessment (LCA) for gauging absolute environmental sustainability. We tested the applicability of a novel Planetary Boundaries-based life cycle impact assessment methodology on a hypothetical laundry washing case study at the EU level. We express the impacts corresponding...... to the control variables of the individual Planetary Boundaries together with a measure of their respective uncertainties. We tested four sharing principles for assigning a share of the safe operating space (SoSOS) to laundry washing and assessed if the impacts were within the assigned SoSOS. The choice...

NOMINAL VALUES FOR SELECTED SOLAR AND PLANETARY QUANTITIES: IAU 2015 RESOLUTION B3

Energy Technology Data Exchange (ETDEWEB)

Prša, Andrej [Villanova University, Department of Astrophysics and Planetary Science, 800 Lancaster Ave., Villanova, PA 19085 (United States); Harmanec, Petr [Astronomical Institute of the Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, CZ-180 00 Praha 8 (Czech Republic); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mamajek, Eric [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Asplund, Martin [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Capitaine, Nicole [SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC, LNE, 61 avenue de lObservatoire, F-75014 Paris (France); Christensen-Dalsgaard, Jørgen [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Depagne, Éric [South African Astronomical Observatory, P.O. Box 9 Observatory, Cape Town (South Africa); Haberreiter, Margit [Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center, Dorfstrasse 33, Davos (Switzerland); Hekker, Saskia [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Hilton, James [US Naval Observatory, 3450 Massachusetts Ave. NW, Washington, DC 20392-5420 (United States); Kopp, Greg [Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, CO 80303-7814 (United States); and others

2016-08-01

In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

NOMINAL VALUES FOR SELECTED SOLAR AND PLANETARY QUANTITIES: IAU 2015 RESOLUTION B3

International Nuclear Information System (INIS)

Prša, Andrej; Harmanec, Petr; Torres, Guillermo; Mamajek, Eric; Asplund, Martin; Capitaine, Nicole; Christensen-Dalsgaard, Jørgen; Depagne, Éric; Haberreiter, Margit; Hekker, Saskia; Hilton, James; Kopp, Greg

2016-01-01

In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

An apodized Kepler periodogram for separating planetary and stellar activity signals

Science.gov (United States)

Gregory, Philip C.

2016-01-01

A new apodized Keplerian (AK) model is proposed for the analysis of precision radial velocity (RV) data to model both planetary and stellar activity (SA) induced RV signals. A symmetrical Gaussian apodization function with unknown width and centre can distinguish planetary signals from SA signals on the basis of the span of the apodization window. The general model for m AK signals includes a linear regression term between RV and the SA diagnostic log (R′hk), as well as an extra Gaussian noise term with unknown standard deviation. The model parameters are explored using a Bayesian fusion Markov chain Monte Carlo code. A differential version of the generalized Lomb–Scargle periodogram that employs a control diagnostic provides an additional way of distinguishing SA signals and helps guide the choice of new periods. Results are reported for a recent international RV blind challenge which included multiple state-of-the-art simulated data sets supported by a variety of SA diagnostics. In the current implementation, the AK method achieved a reduction in SA noise by a factor of approximately 6. Final parameter estimates for the planetary candidates are derived from fits that include AK signals to model the SA components and simple Keplerians to model the planetary candidates. Preliminary results are also reported for AK models augmented by a moving average component that allows for correlations in the residuals. PMID:27346979

MAGLEV `95. 14th international conference on magnetically levitated systems. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-31

The proceedings present the papers of the 14th International Conference on Magnetically Levitated Systems held in Bremen, FRG, in November 1995. For 70 of 74 papers a separate subject analysis has been carried out. 4 papers are not available in the proceedings. (HW)

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.

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)

Instabilities of bellows: Dependence on internal pressure, end supports, and interactions in accelerator magnet systems

International Nuclear Information System (INIS)

Shutt, R.P.; Rehak, M.L.

1990-01-01

For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines in addition to beam tube bellows. There could be approximately 10,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed or internally pressurized, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in an assembly, failure modes might interact. If designed properly, large bellows can be a very feasible possibility for connecting the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We present here (1) a spring-supported bellows model, in order to develop necessary design features for bellows and end supports so that instabilities will not occur in the bellows pressure operating region, including some margin, (2) a model of three superconducting accelerator magnets connected by two large bellows, in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Reliability of bellows for our application will be stressed. 3 refs., 4 figs

ULF Waves Upstream from Planetary Bow Shocks: Application to the Interball-Tail Observations at the Earth

International Nuclear Information System (INIS)

Trotignon, J.G.; Rauch, J.L.; Klimov, S.; Nozdrachev, M.; Romanov, S.; Savin, S.; Skalsky, A.; Blecki, J.; Juchniewicz, J.; Amata, E.

1999-01-01

One of the outstanding problems in solar system plasma physics is the morphology of planetary and cometary foreshocks. A large variety of electron and ion velocity distribution functions, as well as electrostatic and electromagnetic waves phenomena, are indeed currently observed in these regions located upstream from, and magnetically connected to, bow shocks. Foreshocks being complex and highly dynamic, it is not easy to get a comprehensive description of them. Nevertheless, simple geometrical considerations can be of help to order foreshock structures. In light of the great number of results obtained in planetary foreshocks, which are briefly reviewed, we present an ongoing study of the upstream waves observed by the INTERBALL-TAIL magnetometers in the Ultra Low Frequency range. (author)

Experimental and Numerical Studies of Mechanically- and Convectively-Driven Turbulence in Planetary Interiors

Science.gov (United States)

Grannan, Alexander Michael

2017-08-01

The energy for driving turbulent flows in planetary fluid layers comes from a combination of thermocompositional sources and the motion of the boundary in contact with the fluid through mechanisms like precessional, tidal, and librational forcing. Characterizing the resulting turbulent fluid motions are necessary for understanding many aspects of the planet's dynamics and evolution including the generation of magnetic fields in the electrically conducting fluid layers and dissipation in the oceans. Although such flows are strongly inertial they are also strongly influenced by the Coriolis force whose source is in the rotation of the body and tends to constrain the inertial effects and provide support for fluid instabilities that might in-turn generate turbulence. Furthermore, the magnetic fields generated by the electrically conducting fluids act back on the fluid through the Lorentz force that also tends to constrain the flow. The goal of this dissertation is to investigate the characteristics of turbulent flows under the influence of mechanical, convective, rotational and magnetic forcing. In order to investigate the response of the fluid to mechanical forcing, I have modified a unique set of laboratory experiments that allows me to quantify the generation of turbulence driven by the periodic oscillations of the fluid containing boundary through tides and libration. These laboratory experiments replicate the fundamental ingredients found in planetary environments and are necessary for the excitation of instabilities that drive the turbulent fluid motions. For librational forcing, a rigid ellipsoidal container and ellipsoidal shell of isothermal unstratified fluid is made to rotate with a superimposed oscillation while, for tidal forcing, an elastic ellipsoidal container of isothermal unstratified fluid is made to rotate while an independently rotating perturbance also flexes the elastic container. By varying the strength and frequencies of these oscillations the

Planetary maps - Passports for the mind

International Nuclear Information System (INIS)

Anderson, C.M.

1990-01-01

The various types of planetary maps are reviewed. Included are basic descriptions of planimetric, topographic, geologic, and digital maps. It is noted that planimetric maps are pictorial representations of a planet's round surface flattened into a plane, such as controlled photomosaic maps and shaded relief maps. Topographic maps, those usually made with data from altimeters and stereoscopic images, have contour lines indicating the shapes and elevations of landforms. Geologic maps carry additional information about landforms, such as rock types, the processes that formed them, and their relative ages. The International Astronomical Union nomenclature system is briefly discussed, pointing out that the Union often assigns themes to areas to be mapped

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

High speed internal permanent magnet machine and method of manufacturing the same

Science.gov (United States)

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-09-13

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple permanent magnets for generating a magnetic field, which interacts with the stator magnetic field to produce torque. The permanent magnets are disposed between the stacks. The rotor assembly also includes multiple bottom wedges disposed on the bottom structures of the shaft and configured to hold the multiple stacks and the multiple permanent magnets.

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.

Excitation of planetary electromagnetic waves in the inhomogeneous ionosphere

Directory of Open Access Journals (Sweden)

Yu. Rapoport

2014-04-01

Full Text Available In this paper we develop a new method for the analysis of excitation and propagation of planetary electromagnetic waves (PEMW in the ionosphere of the Earth. The nonlinear system of equations for PEMW, valid for any height, from D to F regions, including intermediate altitudes between D and E and between E and F regions, is derived. In particular, we have found the system of nonlinear one-fluid MHD equations in the β-plane approximation valid for the ionospheric F region (Aburjania et al., 2003a, 2005. The series expansion in a "small" (relative to the local geomagnetic field non-stationary magnetic field has been applied only at the last step of the derivation of the equations. The small mechanical vertical displacement of the media is taken into account. We have shown that obtained equations can be reduced to the well-known system with Larichev–Reznik vortex solution in the equatorial region (see e.g. Aburjania et al., 2002. The excitation of planetary electromagnetic waves by different initial perturbations has been investigated numerically. Some means for the PEMW detection and data processing are discussed.

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

Remote Sensing Data Analytics for Planetary Science with PlanetServer/EarthServer

Science.gov (United States)

Rossi, Angelo Pio; Figuera, Ramiro Marco; Flahaut, Jessica; Martinot, Melissa; Misev, Dimitar; Baumann, Peter; Pham Huu, Bang; Besse, Sebastien

2016-04-01

https://github.com/planetserver References: Baumann, P., et al. (2015) Big Data Analytics for Earth Sciences: the EarthServer approach, International Journal of Digital Earth, doi: 10.1080/17538947.2014.1003106. Cantini, F. et al. (2014) Geophys. Res. Abs., Vol. 16, #EGU2014-3784. Gaddis, L., and T. Hare (2015), Status of tools and data for planetary research, Eos, 96, dos: 10.1029/2015EO041125. Hogan, P., 2011. NASA World Wind: Infrastructure for Spatial Data. Technical report. Proceedings of the 2nd International Conference on Computing for Geospatial Research & Applications ACM. Oosthoek, J.H.P, et al. (2013) Advances in Space Research. doi: 10.1016/j.asr.2013.07.002. Rossi, A. P., et al. (2014) PlanetServer/EarthServer: Big Data analytics in Planetary Science. Geophysical Research Abstracts, Vol. 16, #EGU2014-5149.

The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets

Energy Technology Data Exchange (ETDEWEB)

Garraffo, Cecilia; Drake, Jeremy J.; Cohen, Ofer; Alvarado-Gómez, Julian D.; Moschou, Sofia P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2017-07-10

Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf, TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their surface. Temperate terrestrial planets around an M-dwarf orbit close to their parent star, rendering their atmospheres vulnerable to erosion by the stellar wind and energetic electromagnetic and particle radiation. Here, we use state-of-the-art 3D magnetohydrodynamic models to simulate the wind around TRAPPIST-1 and study the conditions at each planetary orbit. All planets experience a stellar wind pressure between 10{sup 3} and 10{sup 5} times the solar wind pressure on Earth. All orbits pass through wind pressure changes of an order of magnitude and most planets spend a large fraction of their orbital period in the sub-Alfvénic regime. For plausible planetary magnetic field strengths, all magnetospheres are greatly compressed and undergo much more dynamic change than that of the Earth. The planetary magnetic fields connect with the stellar radial field over much of the planetary surface, allowing the direct flow of stellar wind particles onto the planetary atmosphere. These conditions could result in strong atmospheric stripping and evaporation and should be taken into account for any realistic assessment of the evolution and habitability of the TRAPPIST-1 planets.

Measurement of internal forces in superconducting accelerator magnets with strain gauge transducers

International Nuclear Information System (INIS)

Goodzeit, C.L.; Anerella, M.D.; Ganetis, G.L.

1988-01-01

An improved method has been developed for the measurement of internal forces in superconducting accelerator magnets, in particular the compressive stresses in coils and the end restraint forces on the coils. The transducers have been designed to provide improved sensitivity to purely mechanical strain by using bending mode deflections for sensing the applied loads. Strain gauge resistance measurements are made with a new system that eliminates sources of errors due to spurious resistance changes in interconnecting wiring and solder joints. The design of the transducers and their measurement system is presented along with a discussion of the method of compensation for thermal and magnetic effects, methods of calibration with typical calibration data, and measured effect in actual magnets of the thermal stress changes from cooldown and the Lorentz forces during magnet excitation. 13 figs., 1 tab

PREFACE: International Conference on Magnetism (ICM 2009)

Science.gov (United States)

Goll, Gernot; Löhneysen, Hilbert v.; Loidl, Alois; Pruschke, Thomas; Richter, Manuel; Schultz, Ludwig; Sürgers, Christoph; Wosnitza, Jochen

2010-11-01

The International Conference on Magnetism 2009 (ICM 2009) was held in Karlsruhe, Germany, from 26-31 July 2009. Previous conferences in this series were organized in Edingburgh, United Kingdom (1991), Warsaw, Poland (1994), Cairns, Australia (1997), Recife, Brazil (2000), Rome, Italy (2003) and Kyoto, Japan (2006). As with previous ICM conferences, the annual Conference on Strongly Correlated Electron Systems (SCES) was integrated into ICM 2009. Conference photograph Participants of ICM 2009 in front of the Stadthalle Karlsruhe. Topics of ICM 2009 were: Strongly Correlated Electron Systems; Quantum and Classical Spin Systems; Magnetic Structures and Interactions; Magnetization Dynamics and Micromagnetics; Spin-Dependent Transport; Spin Electronics; Magnetic Thin Films, Particles, and Nanostructures; Soft and Hard Magnetic Materials and their Applications; Novel Materials and Device Applications; Magnetic Recording and Memories; Measuring Techniques and Instrumentation, as well as Interdisciplinary Topics. We are grateful to the International Advisory Committee for their help in putting up an attractive program encompassing practically all aspects of magnetism, both experimentally and theoretically. The program committee comprised A Loidl, Germany (Chair), M A Continentino, Brazil, D E Dahlberg, USA, D Givord, France, G Güntherodt, Germany, H Mikeska, Germany, D Kaczorowski, Poland, Ching-Ray Chang, South Korea, I Mertig, Germany, D Vollhardt, Germany and E F Wassermann, Germany was also head of the National Organizing Committee. His help is gratefully acknowledged. Photographs Left: Poster session in the Stadthalle Karlsruhe. Upper right: H v Löhneysen (Conference Chairman), Nobel Laureates A Fert and P. Grünberg, E Umbach (Chairman of the Executive Board of Forschungszentrum Karlsruhe) (left to right). Lower right: Nobel Laureate P W Anderson. The scientific program started on Monday 27 July 2009 with opening addresses by the Conference Chairman, the deputy

Simulated orbits of heavy planetary ions at Mars for different IMF configurations

Science.gov (United States)

Curry, Shannon; Luhmann, Janet; Livi, Roberto; Hara, Takuya; Dong, Chuanfei; Ma, Yingjuan; McFadden, James; Bougher, Stephen

2014-11-01

We present simulated detections of O+, O2+ and CO2+ ions at Mars along a virtual orbit in the Mars space environment. Planetary pick-up ions are formed through the direct interaction of the solar wind with the neutral upper atmosphere, causing the newly created ions to be picked up and accelerated by the background convective electric field. Because previous missions such as Mars Global Surveyor (MGS) and Mars Express (MEX) have not been able to measure the interplanetary magnetic field (IMF) components simultaneously with plasma measurements, the response of heavy planetary pick-up ions to changes in the IMF has not been well characterized. Using a steady-state multi-species MHD model to provide the background electric and magnetic fields, the Mars Test Particle (MTP) simulation can trace each of these particles along field lines in near-Mars space and construct virtual ion detections from a spacecraft orbit. Specifically, we will present energy-time spectrograms and velocity space distributions (VSDs) for a selection of orbits during different IMF configurations and solar cycle conditions. These simulated orbits have broader implications for how to measure ion escape. Using individual particle traces, the origin and trajectories of different ion populations can be analyzed in order to assess how and where they contribute to the total atmospheric escape rate, which is a major objective of the upcoming MAVEN mission.

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

Analysis of Dynamic Behavior of Multiple-Stage Planetary Gear Train Used in Wind Driven Generator

Directory of Open Access Journals (Sweden)

Jungang Wang

2014-01-01

Full Text Available A dynamic model of multiple-stage planetary gear train composed of a two-stage planetary gear train and a one-stage parallel axis gear is proposed to be used in wind driven generator to analyze the influence of revolution speed and mesh error on dynamic load sharing characteristic based on the lumped parameter theory. Dynamic equation of the model is solved using numerical method to analyze the uniform load distribution of the system. It is shown that the load sharing property of the system is significantly affected by mesh error and rotational speed; load sharing coefficient and change rate of internal and external meshing of the system are of obvious difference from each other. The study provides useful theoretical guideline for the design of the multiple-stage planetary gear train of wind driven generator.

Mathematical Modeling of Electrodynamics Near the Surface of Earth and Planetary Water Worlds

Science.gov (United States)

Tyler, Robert H.

2017-01-01

An interesting feature of planetary bodies with hydrospheres is the presence of an electrically conducting shell near the global surface. This conducting shell may typically lie between relatively insulating rock, ice, or atmosphere, creating a strong constraint on the flow of large-scale electric currents. All or parts of the shell may be in fluid motion relative to main components of the rotating planetary magnetic field (as well as the magnetic fields due to external bodies), creating motionally-induced electric currents that would not otherwise be present. As such, one may expect distinguishing features in the types of electrodynamic processes that occur, as well as an opportunity for imposing specialized mathematical methods that efficiently address this class of application. The purpose of this paper is to present and discuss such specialized methods. Specifically, thin-shell approximations for both the electrodynamics and fluid dynamics are combined to derive simplified mathematical formulations describing the behavior of these electric currents as well as their associated electric and magnetic fields. These simplified formulae allow analytical solutions featuring distinct aspects of the thin-shell electrodynamics in idealized cases. A highly efficient numerical method is also presented that is useful for calculations under inhomogeneous parameter distributions. Finally, the advantages as well as limitations in using this mathematical approach are evaluated. This evaluation is presented primarily for the generic case of bodies with water worlds or other thin spherical conducting shells. More specific discussion is given for the case of Earth, but also Europa and other satellites with suspected oceans.

Early-career experts essential for planetary sustainability

Science.gov (United States)

Lim, Michelle; Lynch, Abigail J.; Fernández-Llamazares, Alvaro; Balint, Lenke; Basher, Zeenatul; Chan, Ivis; Jaureguiberry, Pedro; Mohamed, A.A.A.; Mwampamba, Tuyeni H.; Palomo, Ignacio; Pliscoff, Patricio; Salimov, R.A.; Samakov, Aibek; Selomane, Odirilwe; Shrestha, Uttam B.; Sidorovich, Anna A.

2017-01-01

Early-career experts can play a fundamental role in achieving planetary sustainability by bridging generational divides and developing novel solutions to complex problems. We argue that intergenerational partnerships and interdisciplinary collaboration among early-career experts will enable emerging sustainability leaders to contribute fully to a sustainable future. We review 16 international, interdisciplinary, and sustainability-focused early-career capacity building programs. We conclude that such programs are vital to developing sustainability leaders of the future and that decision-making for sustainability is likely to be best served by strong institutional cultures that promote intergenerational learning and involvement.

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...

Enabling interoperability in planetary sciences and heliophysics: The case for an information model

Science.gov (United States)

Hughes, J. Steven; Crichton, Daniel J.; Raugh, Anne C.; Cecconi, Baptiste; Guinness, Edward A.; Isbell, Christopher E.; Mafi, Joseph N.; Gordon, Mitchell K.; Hardman, Sean H.; Joyner, Ronald S.

2018-01-01

The Planetary Data System has developed the PDS4 Information Model to enable interoperability across diverse science disciplines. The Information Model is based on an integration of International Organization for Standardization (ISO) level standards for trusted digital archives, information model development, and metadata registries. Where controlled vocabularies provides a basic level of interoperability by providing a common set of terms for communication between both machines and humans the Information Model improves interoperability by means of an ontology that provides semantic information or additional related context for the terms. The information model was defined by team of computer scientists and science experts from each of the diverse disciplines in the Planetary Science community, including Atmospheres, Geosciences, Cartography and Imaging Sciences, Navigational and Ancillary Information, Planetary Plasma Interactions, Ring-Moon Systems, and Small Bodies. The model was designed to be extensible beyond the Planetary Science community, for example there are overlaps between certain PDS disciplines and the Heliophysics and Astrophysics disciplines. "Interoperability" can apply to many aspects of both the developer and the end-user experience, for example agency-to-agency, semantic level, and application level interoperability. We define these types of interoperability and focus on semantic level interoperability, the type of interoperability most directly enabled by an information model.

Equilibrium positions on stationary orbits and planetary principal inertia axis orientations for the Solar System

Science.gov (United States)

Romero, Pilar; Barderas, Gonzalo; Mejuto, Javier

2018-05-01

We present a qualitative analysis in a phase space to determine the longitudinal equilibrium positions on the planetary stationary orbits by applying an analytical model that considers linear gravitational perturbations. We discuss how these longitudes are related with the orientation of the planetary principal inertia axes with respect to their Prime Meridians, and then we use this determination to derive their positions with respect to the International Celestial Reference Frame. Finally, a numerical analysis of the non-linear effects of the gravitational fields on the equilibrium point locations is developed and their correlation with gravity field anomalies shown.

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…

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

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

A Substantial Plume of Escaping Planetary Ions in the MSE Northern Hemisphere Observed by MAVEN

Science.gov (United States)

Dong, Y.; Fang, X.; Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.; Curry, S.; Harada, Y.; Luhmann, J. G.; Jakosky, B. M.

2015-12-01

The Mars-solar wind interaction accelerates and transports planetary ions away from Mars through a number of processes, including pick-up by the electromagnetic fields. The Mars Atmospheric and Volatile EvolutioN (MAVEN) spacecraft has frequently detected strong escaping planetary ion fluxes in both tailward and upstream solar wind motional electric field directions since the beginning of its science phase in November 2014. Our statistical study using three-month MAVEN data from November 2014 through February 2015 illustrates a substantial plume-like escaping planetary ion population organized by the upstream electric field with strong fluxes widely distributed in the northern hemisphere of the Mars-Sun-Electric-field (MSE) coordinate system, which is generally consistent with model predictions. The plume constitutes an important planetary ion escape channel from the Martian atmosphere in addition to the tailward escape. The >25eV O+ escape rate through the plume is estimated to be ~35% of the tailward escape and ~25% of the total escape. We will compare the dynamics of the plume and tailward escaping ions based on their velocity-space distributions with respect to the electromagnetic fields. We will also discuss the variations of the plume characteristics between different ion species (O+, O2+, and CO2+) and from the effect of different solar wind and interplanetary magnetic field (IMF) conditions.

Cosmic Education: Formation of a Planetary and Cosmic Personality

Directory of Open Access Journals (Sweden)

Bazaluk Oleg

2012-04-01

Full Text Available The major stages of development of cosmic pedagogy have been researched. Based on the achievements of the modern neurosciences as well as of psychology, cosmology, and philosophy, the authors provide their reasoning for the cosmic education and its outlooks for the educational systems of the world. Through the studies of how important human mind is for the Earth and the cosmos and by researching the evolution of human mind within the structure of the Universe, the authors create a more advanced scientific and philosophic basis for the cosmic education where the subject is a comprehensive process of formation and directed progress of both an individual mind and a conglomerate of minds called the "psychospace". The cosmic education researches the permanent progress of the intelligent matter of the Earth. The purpose of the cosmic education has been determined as formation of a planetary and cosmic personality. According to the authors, a planetary and cosmic personality is a harmony of mind, soul, and body, and such harmony is directed to use the internal creative potential of mind to the benefit of the intelligent matter of the entire Earth and the cosmos. The properties of such a planetary and cosmic personality are being improved continuously; they are a sample (the ideal of the cosmic pedagogy and the image of a human being of the future. Through the usage of the entire potential and art of upbringing and educating, the cosmic pedagogy is called to embody the major properties of the image of a human being of the future in the new generations of minds and to form a planetary and cosmic personality capable of self-actualization to the benefit of the permanent progress of the intelligent matter.

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.

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)

Close binary evolution. II. Impact of tides, wind magnetic braking, and internal angular momentum transport

Science.gov (United States)

Song, H. F.; Meynet, G.; Maeder, A.; Ekström, S.; Eggenberger, P.; Georgy, C.; Qin, Y.; Fragos, T.; Soerensen, M.; Barblan, F.; Wade, G. A.

2018-01-01

Context. Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-initial-mass stars. In a close binary system, the effect of wind magnetic braking also interacts with the influence of tides, resulting in a complex evolution of rotation. Aims: We study the interactions between the process of wind magnetic braking and tides in close binary systems. Methods: We discuss the evolution of a 10 M⊙ star in a close binary system with a 7 M⊙ companion using the Geneva stellar evolution code. The initial orbital period is 1.2 days. The 10 M⊙ star has a surface magnetic field of 1 kG. Various initial rotations are considered. We use two different approaches for the internal angular momentum transport. In one of them, angular momentum is transported by shear and meridional currents. In the other, a strong internal magnetic field imposes nearly perfect solid-body rotation. The evolution of the primary is computed until the first mass-transfer episode occurs. The cases of different values for the magnetic fields and for various orbital periods and mass ratios are briefly discussed. Results: We show that, independently of the initial rotation rate of the primary and the efficiency of the internal angular momentum transport, the surface rotation of the primary will converge, in a time that is short with respect to the main-sequence lifetime, towards a slowly evolving velocity that is different from the synchronization velocity. This "equilibrium angular velocity" is always inferior to the angular orbital velocity. In a given close binary system at this equilibrium stage, the difference between the spin and the orbital angular velocities becomes larger when the mass losses and/or the surface magnetic field increase. The

Proceedings of The Twentieth International Symposium on Space Technology and Science. Volume 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-10-31

The 20th international symposium on space technology and science was held in Nagaragawa city, Gifu prefecture on May 19-25, 1996, and 401 papers were made public. Out of those, 112 papers were summed up as Volume 2 following the previous Volume 1. As to space transportation, the paper included reports titled as follows: Conceptual study of H-IIA rocket (upgraded H-II rocket); Test flight of the launch vehicle; International cooperation in space transportation; etc. Concerning microgravity science, Recent advances in microgravity research; Use of microgravity environment to investigate the effect of magnetic field on flame shape; etc. Relating to satellite communications and broadcasting, `Project GENESYS`: CRL`s R and D project for realizing high data rate satellite communications networks; The Astrolink {sup TM/SM} system; etc. Besides, the paper contained reports on the following fields: lunar and planetary missions and utilization, space science and balloons, earth observations, life science and human presence, international cooperation and space environment, etc

Depletion of solar wind plasma near a planetary boundary

International Nuclear Information System (INIS)

Zwan, B.J.; Wolf, R.A.

1976-01-01

A mathematical model is presented that describes the squeezing of solar wind plasma out along interplanetary magnetic field lines in the region between the bow shock and the effective planetary boundary (in the case of the earth, the magnetopause). In the absence of local magnetic merging the squeezing process should create a 'depletion layer,' a region of very low plasma density just outside the magnetopause. Numerical solutions are obtained for the dimensionless magnetohydrodynamic equations describing this depletion process for the case where the solar wind magnetic field is perpendicular to the solar wind flow direction. For the case of the earth with a magnetopause standoff distance of 10 R/subE/, the theory predicts that the density should be reduced by a factor > or =2 in a layer about 700--1300 km thick if M/subA/, the Alfven Mach number in the solar wind, is equal to 8. The layer thickness should vary as M/subA/ -2 and should be approximately uniform for a large area of the magnetopause around the subsolar point. Computed layer thicknesses are somewhat smaller than those derived from Lees' axisymmetric model. Depletion layers should develop fully only where magnetic merging is locally unimportant. Scaling of the model calculations to Venus and Mars suggest layer thicknesses about 1/10 and 1/15 those of the earth, respectively, neglecting diffusion and ionospheric effects

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.

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

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.

The Alpha Magnetic Spectrometer (AMS) experiment on the International Space Station

Energy Technology Data Exchange (ETDEWEB)

Alpat, Behcet E-mail: behcet.alpat@pg.infn.it

2001-04-01

The Alpha Magnetic Spectrometer (AMS) is a detector designed to operate in space to search for antimatter components in cosmic ray, the annihilation products of darkmatter and to study the antiprotons, positrons and light nuclei. A 'baseline' version of the experiment has successfully completed the precursor flight on Space Shuttle Discovery (June 2-12, 1998). The complete AMS is programmed for installation on International Space Station in year 2003 for an operational period of 3 years. In this contribution we report on the experimental configuration of AMS that will be installed on International Space Station.

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.

Measurement of internal defects in aluminum using a nano-granular in-gap magnetic sensor

Science.gov (United States)

Ozawa, T.; Yabukami, S.; Totsuka, J.; Koyama, S.; Hayasaka, J.; Wako, N.; Arai, K. I.

2015-05-01

Techniques for identifying defects in metals are very important in a wide variety of manufacturing areas. The present paper reports an eddy current testing method that employs a nano-granular in-gap magnetic sensor (GIGS) to detect internal defects in aluminum boards. The GIGS consists of a tunnel magnetoresistive film with nanometer sized grains and two yokes. In the presence of an external magnetic field, the nano-granular film exhibits only a small change in resistance due to the tunnel magnetoresistive effect. However, by placing it between two yokes, the magnetic flux can be greatly concentrated, thus increasing the change in resistance. The GIGS is a magnetic-field sensor that exploits this principle to achieve enhanced sensitivity. Moreover, because it has a cross-sectional yolk area of just 80 μm × 0.5 μm, it achieves outstanding spatial resolution. In the present study, it is used in combination with an eddy-current method in order to detect internal defects in aluminum. In this method, an excitation coil is used to apply an AC magnetic field perpendicular to the aluminum surface. This induces eddy currents in the metal, which in turn give rise to an AC magnetic field, which is then measured by the GIGS. The presence of defects in the aluminum distorts the eddy current flow, causing a change in the magnitude and distribution of the magnetic field. Such changes can be detected using the GIGS. In the present study, the proposed method was used to successfully detect indentations with diameters of 5 mm on the rear surface of an aluminum plate.

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.

Preparation of ring-shaped composite bonded magnets with continuously controlled anisotropy distribution for internal space

International Nuclear Information System (INIS)

Yamashita, F; Yamada, O; Ohya, S; Kobayashi, O; Nakano, M; Fukunaga, H

2010-01-01

We have already reported an advanced method for producing a radially-anisotropic rare earth composite bonded magnet with continuously controlled direction of anisotropy. The magnet has been applied to an inner rotor as a practical usage. In this study, the outstanding preparation method was adopted into the preparation of a magnet applied for an outer rotor. An optimized condition of extrusion and compaction at an elevated temperature could be obtained. In addition, a low pressure configuration to the ring-shaped magnet from plural preformed magnets was carried out, which had specific distribution of magnetic anisotropy for internal space for a small motor, by using self recoverability based on the viscous deformation without an alignment field. No deterioration of magnetic properties was detected through the process even if those magnets were miniaturized. Resultantly, the (BH) max of a ring-shaped magnet with the continuously controlled direction of magnetic anisotropy attained the value of 186 kJ/m 3 , and we obtained sine-wave magnetic anisotropy distribution, even if those magnets were miniaturized.

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

Magnetic properties of Proxima Centauri b analogues

Science.gov (United States)

Zuluaga, Jorge I.; Bustamante, Sebastian

2018-03-01

The discovery of a planet around the closest star to our Sun, Proxima Centauri, represents a quantum leap in the testability of exoplanetary models. Unlike any other discovered exoplanet, models of Proxima b could be contrasted against near future telescopic observations and far future in-situ measurements. In this paper we aim at predicting the planetary radius and the magnetic properties (dynamo lifetime and magnetic dipole moment) of Proxima b analogues (solid planets with masses of ∼ 1 - 3M⊕ , rotation periods of several days and habitable conditions). For this purpose we build a grid of planetary models with a wide range of compositions and masses. For each point in the grid we run the planetary evolution model developed in Zuluaga et al. (2013). Our model assumes small orbital eccentricity, negligible tidal heating and earth-like radiogenic mantle elements abundances. We devise a statistical methodology to estimate the posterior distribution of the desired planetary properties assuming simple lprior distributions for the orbital inclination and bulk composition. Our model predicts that Proxima b would have a mass 1.3 ≤Mp ≤ 2.3M⊕ and a radius Rp =1.4-0.2+0.3R⊕ . In our simulations, most Proxima b analogues develop intrinsic dynamos that last for ≥4 Gyr (the estimated age of the host star). If alive, the dynamo of Proxima b have a dipole moment ℳdip >0.32÷2.9×2.3ℳdip , ⊕ . These results are not restricted to Proxima b but they also apply to earth-like planets having similar observed properties.

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 ...

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.

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

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.

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

Measurement of internal magnetic field pitch using Li pellet injection on TFTR (invited)

International Nuclear Information System (INIS)

Terry, J.L.; Marmar, E.S.; Howell, R.B.; Bell, M.; Cavallo, A.; Fredrickson, E.; Ramsey, A.; Schmidt, G.L.; Stratton, B.; Taylor, G.; Mauel, M.E.

1990-01-01

A diagnostic technique which measures the direction of the internal magnetic field pitch angle has been used successfully on TFTR. The technique requires the injection of high-speed Li pellets. The magnetic field direction is measured by observing the polarization direction of the intense visible line emission from Li + (λ∼5485 A, 1s2p 3 P 0,1,2 →1s2s 3 S 0 ) in the pellet ablation cloud. The presence of the large (primarily toroidal) magnetic field causes the line to be split due to the Zeeman effect, and the unshifted π component is polarized with its polarization direction parallel to the local magnetic field. In devices with sufficiently strong fields (B approx-gt 4.5 T), the Zeeman splitting of the line is large enough, relative to the linewidth of each Zeeman component, that enough residual polarization remains. Because the pellet moves about 1 cm before the Li + is ionized (τ ionization approx-lt 10 μs), the time history of the polarization direction (as the pellet penetrates from the outside toward the plasma center) yields the local magnetic field direction. In the TFTR experiment, spatial resolution of the measurement is typically ∼7 cm, limited by the requirement that a large number of photons must be collected in order to make the measurement of the polarization angle. Typically, the pitch of the field is measured with an accuracy of ±0.01 rad, limited by the photon statistics. The measurements of the internal field pitch angle, combined with external magnetic measurements, have been used in a code which finds the solution of the Grad--Shafranov equation, yielding the equilibrium which is the best fit to the measured inputs

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.

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.

Artificial neural network methodology: Application to predict magnetic properties of nanocrystalline alloys

International Nuclear Information System (INIS)

Hamzaoui, R.; Cherigui, M.; Guessasma, S.; ElKedim, O.; Fenineche, N.

2009-01-01

This paper is dedicated to the optimization of magnetic properties of iron based magnetic materials with regard to milling and coating process conditions using artificial neural network methodology. Fe-20 wt.% Ni and Fe-6.5 wt.% Si, alloys were obtained using two high-energy ball milling technologies, namely a planetary ball mill P4 vario ball mill from Fritsch and planetary ball mill from Retch. Further processing of Fe-Si powder allowed the spraying of the feedstock material using high-velocity oxy-fuel (HVOF) process to obtain a relatively dense coating. Input parameters were the disc Ω and vial ω speed rotations for the milling technique, and spray distance and oxygen flow rate in the case of coating process. Two main magnetic parameters are optimized namely the saturation magnetization and the coercivity. Predicted results depict clearly coupled effects of input parameters to vary magnetic parameters. In particular, the increase of saturation magnetization is correlated to the increase of the product Ωω (shock power) and the product of spray parameters. Largest coercivity values are correlated to the increase of the ratio Ω/ω (shock mode process) and the increase of the product of spray parameters.

Physics of magnetic flux ropes

Science.gov (United States)

Russell, C. T.; Priest, E. R.; Lee, L. C.

The present work encompasses papers on the structure, waves, and instabilities of magnetic flux ropes (MFRs), photospheric flux tubes (PFTs), the structure and heating of coronal loops, solar prominences, coronal mass ejections and magnetic clouds, flux ropes in planetary ionospheres, the magnetopause, magnetospheric field-aligned currents and flux tubes, and the magnetotail. Attention is given to the equilibrium of MFRs, resistive instability, magnetic reconnection and turbulence in current sheets, dynamical effects and energy transport in intense flux tubes, waves in solar PFTs, twisted flux ropes in the solar corona, an electrodynamical model of solar flares, filament cooling and condensation in a sheared magnetic field, the magnetopause, the generation of twisted MFRs during magnetic reconnection, ionospheric flux ropes above the South Pole, substorms and MFR structures, evidence for flux ropes in the earth magnetotail, and MFRs in 3D MHD simulations.

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.

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

Space and Planetary Resources

Science.gov (United States)

Abbud-Madrid, Angel

2018-02-01

exploiting the resources from asteroids, the Moon, and Mars, an international legal framework is also needed to regulate commercial exploration and the use of space and planetary resources for the benefit of all humanity. These resources hold the secret to unleash an unprecedented wave of exploration and of economic prosperity by utilizing the full potential and value of space. It is up to us humans here on planet Earth to find the best way to use these extraterrestrial resources effectively and responsibly to make this promise a reality.

PREFACE: The International Conference on Highly Frustrated Magnetism HFM2008

Science.gov (United States)

Eremin, Ilya; Brenig, Wolfram; Kremer, Reinhard; Litterst, Jochen

2009-01-01

The International Conference on Highly Frustrated Magnetism 2008 (HFM2008) took place on 7-12 September 2008 at the Technische Universität Carolo-Wilhelmina zu Braunschweig, Germany. This conference was the fourth event in a series of meetings, which started in Waterloo, Canada (HFM 2000), followed by the second one in Grenoble, France (HFM 2003), and the third meeting in Osaka, Japan (HFM 2006). HFM2008 attracted more than 220 participants from all over the world. The number of participants of the HFM conference series has been increasing steadily, from about 80 participants at HFM 2000, to 120 participants at HFM 2003, and 190 participants at HFM 2006, demonstrating that highly frustrated magnetism remains a rapidly growing area of research in condensed matter physics. At the end of HFM2008 it was decided that the next International Conference on Highly Frustrated Magnetism will be held in Baltimore, USA in 2010. HFM2008 saw four plenary talks by R Moessner, S Nakatsuji, S-W Cheong, and S Sachdev, 18 invited presentations, 30 contributed talks and about 160 poster presentations from all areas of frustrated magnetism. The subjects covered by the conference included: Kagome systems Itinerant frustrated systems Spinels and pyrochlore materials Triangular systems Unconventional order and spin liquids Chain systems Chain systems Novel frustrated systems This volume of Journal of Physics: Conference Series contains the proceedings of HFM2008 with 83 papers that provide a scientific record of the scientific topics covered by the conference. All articles have been refereed by experts in the field. It is our hope that the reader will enjoy and profit from the HFM2008 Proceedings. Ilya Eremin Proceedings Editor Wolfram Brenig, Reinhard Kremer, and Jochen Litterst Co-Editors International Advisory Board L Balents (USA) F Becca (Italy) S Bramwell (UK) P Fulde (Germany) B D Gaulin (Canada) J E Greedan (Canada) A Harrison (France) Z Hiroi (Japan) H Kawamura (Japan) A Keren

Experimental Investigations of Noise Control in Planetary Gear Set by Phasing

Directory of Open Access Journals (Sweden)

S. H. Gawande

2014-01-01

Full Text Available Now a days reduction of gear noise and resulting vibrations has received much attention of the researchers. The internal excitation caused by the variation in tooth mesh stiffness is a key factor in causing vibration. Therefore to reduce gear noise and vibrations several techniques have been proposed in recent years. In this research the experimental work is carried out to study the effect of planet phasing on noise and subsequent resulting vibrations of Nylon-6 planetary gear drive. For this purpose experimental set-up was built and trials were conducted for two different arrangements (i.e., with phasing and without phasing and it is observed that the noise level and resulting vibrations were reduced by planet phasing arrangement. So from the experimental results it is observed that by applying the meshing phase difference one can reduce planetary gear set noise and vibrations.

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)

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;

Reversing the polarity of a cochlear implant magnet after magnetic resonance imaging.

Science.gov (United States)

Jeon, Ju Hyun; Bae, Mi Ran; Chang, Jae Won; Choi, Jae Young

2012-08-01

The number of patients with cochlear implant (CI) has been rapidly increasing in recent years, and these patients show a growing need of examination by magnetic resonance imaging (MRI). However, the use of MRI on patients with CI is restricted by the internal magnet of the CI. Many studies have investigated the safety of performing 1.5T MRI on patients with CI, which is now being practiced in a clinical setting. We experienced a case in which the polarity of the cochlear implant magnet was reversed after the patient was examined using 1.5T MRI. The external device was attached to the internal device oppositely. We could not find displacement of the internal device, magnet, or electrode upon radiological evaluation. We came up with two possible mechanisms by which the polarity of the magnet reversed. The first possibility was that the magnetic field of MRI reversed the polarity of the magnet. The second was that the internal magnet was physically realigned while interacting with the MRI. We believe the second hypothesis to be more reliable. A removable magnet and a loose magnet boundary of a CI device may have allowed for physical reorientation of the internal magnet. Therefore, in order to avoid these complications, first, the internal magnet must not be aligned anti-parallel with the magnetic polarity of MRI. In the Siemens MRI, the vector of the magnetic field is downward, so implant site should be placed in facing upwards to minimize demagnetization. In the GE Medical Systems MRI, the vector of the magnetic field is upward, so the implant site should be placed facing downwards. Second, wearing of a commercial mold which is fixed to the internal device before performing MRI can be helpful. In addition, any removable internal magnets in a CI device should be removed before MRI, especially in the trunk. However, to ultimately solve this problem, the pocket of the internal magnet should be redesigned for safety. Copyright © 2011. Published by Elsevier Ireland Ltd.

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

Earth and planetary sciences

International Nuclear Information System (INIS)

Wetherill, G.W.; Drake, C.L.

1980-01-01

The earth is a dynamic body. The major surface manifestation of this dynamism has been fragmentation of the earth's outer shell and subsequent relative movement of the pieces on a large scale. Evidence for continental movement came from studies of geomagnetism. As the sea floor spreads and new crust is formed, it is magnetized with the polarity of the field at the time of its formation. The plate tectonics model explains the history, nature, and topography of the oceanic crust. When a lithospheric plate surmounted by continental crust collides with an oceanic lithosphere, it is the denser oceanic lithosphere that is subducted. Hence the ancient oceans have vanished and the knowledge of ancient earth will require deciphering the complex continental geological record. Geochemical investigation shows that the source region of continental rocks is not simply the depleted mantle that is characteristic of the source region of basalts produced at the oceanic ridges. The driving force of plate tectonics is convection within the earth, but much remains to be learned about the convection and interior of the earth. A brief discussion of planetary exploration is given

The architecture and formation of the Kepler-30 planetary system

Science.gov (United States)

Panichi, F.; Goździewski, K.; Migaszewski, C.; Szuszkiewicz, E.

2018-04-01

We study the orbital architecture, physical characteristics of planets, formation and long-term evolution of the Kepler-30 planetary system, detected and announced in 2012 by the KEPLER team. We show that the Kepler-30 system belongs to a particular class of very compact and quasi-resonant, yet long-term stable planetary systems. We re-analyse the light curves of the host star spanning Q1-Q17 quarters of the KEPLER mission. A huge variability of the Transit Timing Variations (TTV) exceeding 2 days is induced by a massive Jovian planet located between two Neptune-like companions. The innermost pair is near to the 2:1 mean motion resonance (MMR), and the outermost pair is close to higher order MMRs, such as 17:7 and 7:3. Our re-analysis of photometric data allows us to constrain, better than before, the orbital elements, planets' radii and masses, which are 9.2 ± 0.1, 536 ± 5, and 23.7 ± 1.3 Earth masses for Kepler-30b, Kepler-30c and Kepler-30d, respectively. The masses of the inner planets are determined within ˜1% uncertainty. We infer the internal structures of the Kepler-30 planets and their bulk densities in a wide range from (0.19 ± 0.01) g.cm-3 for Kepler-30d, (0.96 ± 0.15) g.cm-3 for Kepler-30b, to (1.71 ± 0.13) g.cm-3 for the Jovian planet Kepler-30c. We attempt to explain the origin of this unique planetary system and a deviation of the orbits from exact MMRs through the planetary migration scenario. We anticipate that the Jupiter-like planet plays an important role in determining the present dynamical state of this system.

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.

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.

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…

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.

Quantification of disc displacement in internal derangement of the temporomandibular joint using magnetic resonance imaging.

Science.gov (United States)

Arayasantiparb, Raweewan; Tsuchimochi, Makoto

2010-02-01

Many measures have been developed to determine the extent of disc displacement in internal derangements of the temporomandibular joint (TMJ) using magnetic resonance imaging. The purpose of this study was to develop a quantitative method of analyzing disc position and to evaluate the positions of the disc in internal derangements of the TMJ (group 1, with reduction; group 2, without reduction). Magnetic resonance images of 150 TMJs in 20 healthy volunteers and 55 patients with internal derangements were evaluated. The anatomical points of interest of the TMJ, including the anterior (DA) and posterior (DP) points of the disc, were marked on parasagittal magnetic resonance images of the TMJ disc taken in both the closed- and the open-mouth positions. All points were recorded using an x-y coordinate system, with reference to a referral line. In the closed-mouth position, the DP in patients in group 1 was situated in a more-anterior direction than the DP in volunteers. The DP in group 2 was located further anterior and inferior than the DP in group 1. However, the position of the DA did not differ between group 1 and group 2. In the open-mouth position, the DP was displaced anteroinferiorly to a greater extent in group 2 than in group 1 (one-way ANOVA, followed by Scheffe's test; P displaced TMJ discs revealed no significant difference. In conclusion, most of our results quantitatively support previously reported findings in imaging, surgical, and histopathological studies of TMJ internal derangement. We suggest that our measure of disc position of the TMJ would be useful to assess the status and response to treatment of internal derangements of the TMJ.

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

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

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.

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...

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)

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.

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.

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...

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

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.)

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.

How to bring absolute sustainability into decision-making: An industry case study using a Planetary Boundary-based methodology.

Science.gov (United States)

Ryberg, Morten W; Owsianiak, Mikołaj; Clavreul, Julie; Mueller, Carina; Sim, Sarah; King, Henry; Hauschild, Michael Z

2018-09-01

The Planetary Boundaries concept has emerged as a framework for articulating environmental limits, gaining traction as a basis for considering sustainability in business settings, government policy and international guidelines. There is emerging interest in using the Planetary Boundaries concept as part of life cycle assessment (LCA) for gauging absolute environmental sustainability. We tested the applicability of a novel Planetary Boundaries-based life cycle impact assessment methodology on a hypothetical laundry washing case study at the EU level. We express the impacts corresponding to the control variables of the individual Planetary Boundaries together with a measure of their respective uncertainties. We tested four sharing principles for assigning a share of the safe operating space (SoSOS) to laundry washing and assessed if the impacts were within the assigned SoSOS. The choice of sharing principle had the greatest influence on the outcome. We therefore highlight the need for more research on the development and choice of sharing principles. Although further work is required to operationalize Planetary Boundaries in LCA, this study shows the potential to relate impacts of human activities to environmental boundaries using LCA, offering company and policy decision-makers information needed to promote environmental sustainability. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

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

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

THE INFLUENCE OF THERMAL EVOLUTION IN THE MAGNETIC PROTECTION OF TERRESTRIAL PLANETS

Energy Technology Data Exchange (ETDEWEB)

Zuluaga, Jorge I.; Bustamante, Sebastian; Cuartas, Pablo A. [Instituto de Fisica-FCEN, Universidad de Antioquia, Calle 67 No. 53-108, Medellin (Colombia); Hoyos, Jaime H., E-mail: jzuluaga@fisica.udea.edu.co, E-mail: sbustama@pegasus.udea.edu.co, E-mail: p.cuartas@fisica.udea.edu.co, E-mail: jhhoyos@udem.edu.co [Departamento de Ciencias Basicas, Universidad de Medellin, Carrera 87 No. 30-65, Medellin (Colombia)

2013-06-10

Magnetic protection of potentially habitable planets plays a central role in determining their actual habitability and/or the chances of detecting atmospheric biosignatures. Here we develop a thermal evolution model of potentially habitable Earth-like planets and super-Earths (SEs). Using up-to-date dynamo-scaling laws, we predict the properties of core dynamo magnetic fields and study the influence of thermal evolution on their properties. The level of magnetic protection of tidally locked and unlocked planets is estimated by combining simplified models of the planetary magnetosphere and a phenomenological description of the stellar wind. Thermal evolution introduces a strong dependence of magnetic protection on planetary mass and rotation rate. Tidally locked terrestrial planets with an Earth-like composition would have early dayside magnetopause distances between 1.5 and 4.0 R{sub p} , larger than previously estimated. Unlocked planets with periods of rotation {approx}1 day are protected by magnetospheres extending between 3 and 8 R{sub p} . Our results are robust in comparison with variations in planetary bulk composition and uncertainties in other critical model parameters. For illustration purposes, the thermal evolution and magnetic protection of the potentially habitable SEs GL 581d, GJ 667Cc, and HD 40307g were also studied. Assuming an Earth-like composition, we found that the dynamos of these planets are already extinct or close to being shut down. While GL 581d is the best protected, the protection of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic conditions, seems to be severely exposed to the stellar wind, and, under the conditions of our model, has probably suffered massive atmospheric losses.

Selection of the optimum magnet design for the International Linear Collider positron source helical undulator

Directory of Open Access Journals (Sweden)

D. J. Scott

2007-03-01

Full Text Available A comparison of possible undulator designs for the International Linear Collider positron source has resulted in a superconducting bifilar wire design being selected. After a comprehensive paper study and fabrication of the two preeminent designs, the superconducting undulator was chosen instead of the permanent magnet alternative. This was because of its superior performance in terms of magnetic field strength and quality, operational flexibility, risk of radiation damage, ease in achieving the required vacuum, and cost. The superconducting undulator design will now be developed into a complete system design for the full 200 m long magnet that is required.

Magnetic Fields above the Surface of aSuperconductor with Internal Magnetism

Energy Technology Data Exchange (ETDEWEB)

Bluhm, Hendrik; /Stanford U., Phys. Dept. /SLAC, SSRl

2007-06-26

The author presents a method for calculating the magnetic fields near a planar surface of a superconductor with a given intrinsic magnetization in the London limit. He computes solutions for various magnetic domain boundary configurations and derives relations between the spectral densities of the magnetization and the resulting field in the vacuum half space, which are useful if the magnetization can be considered as a statistical quantity and its features are too small to be resolved individually. The results are useful for analyzing and designing magnetic scanning experiments. Application to existing data from such experiments on Sr{sub 2}RuO{sub 4} show that a domain wall would have been detectable, but the magnetic field of randomly oriented small domains and small defects may have been smaller than the experimental noise level.

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.

Studies in matter antimatter separation and in the origin of lunar magnetism. Annual progress report, 1 Sep 1974--31 Aug 1975

International Nuclear Information System (INIS)

Barker, W.A.; Greeley, R.; Parkin, C.; Aggarwal, H.; Schultz, P.

1975-01-01

A progress report covering lunar and planetary research is introduced. Data cover lunar ionospheric models, lunar and planetary geology, and lunar magnetism. Wind tunnel simulations of Mars aeolian problems and a comparative study of basaltic analogs of Lunar and Martial volcanic features was discussed

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

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.

Preparing Graduate Students for Solar System Science and Exploration Careers: Internships and Field Training Courses led by the Lunar and Planetary Institute

Science.gov (United States)

Shaner, A. J.; Kring, D. A.

2015-12-01

To be competitive in 21st century science and exploration careers, graduate students in planetary science and related disciplines need mentorship and need to develop skills not always available at their home university, including fieldwork, mission planning, and communicating with others in the scientific and engineering communities in the U.S. and internationally. Programs offered by the Lunar and Planetary Institute (LPI) address these needs through summer internships and field training programs. From 2008-2012, LPI hosted the Lunar Exploration Summer Intern Program. This special summer intern program evaluated possible landing sites for robotic and human exploration missions to the lunar surface. By the end of the 2012 program, a series of scientifically-rich landing sites emerged, some of which had never been considered before. Beginning in 2015 and building on the success of the lunar exploration program, a new Exploration Science Summer Intern Program is being implemented with a broader scope that includes both the Moon and near-Earth asteroids. Like its predecessor, the Exploration Science Summer Intern Program offers graduate students a unique opportunity to integrate scientific input with exploration activities in a way that mission architects and spacecraft engineers can use. The program's activities may involve assessments and traverse plans for a particular destination or a more general assessment of a class of possible exploration targets. Details of the results of these programs will be discussed. Since 2010 graduate students have participated in field training and research programs at Barringer (Meteor) Crater and the Sudbury Impact Structure. Skills developed during these programs prepare students for their own thesis studies in impact-cratered terrains, whether they are on the Earth, the Moon, Mars, or other solar system planetary surface. Future field excursions will take place at these sites as well as the Zuni-Bandera Volcanic Field. Skills

EDITORIAL: Selected papers from the 19th International Colloquium on Magnetic Films and Surfaces

Science.gov (United States)

Miyazaki, T.; Inoue, J.

2007-03-01

The 19th International Colloquium on Magnetic Films and Surfaces (ICMFS 2006) was held on 14-18 August 2006 at the Sendai International Center in Sendai, Japan. The purpose of the Colloquium was to bring together scientists working on magnetic thin films and surfaces and to provide an opportunity for presentation and discussion of recent experimental and theoretical advances in the field. 285 scientists from 17 countries (Japan: 167, overseas: 118) participated in the Colloquium, as well as 6 family members. There were 56 oral and 178 poster presentations. The oral presentations consisted of 3 plenary talks, 23 invited talks and 30 contributed talks. The number of presentations by scientific category are as follows: Spin dependent transport: 43 Magnetic storage/memory: 9 Magnetization reversal and fast dynamics: 15 Spin injection and spin transfer torque: 26 Magnetic thin films and multilayers: 71 High spin polarization materials: 17 Hard and soft magnetic materials: 3 Magneto-optics: 5 Characterization techniques for thin films and surfaces: 7 Exchange coupling: 13 Micro- and nanopatterned magnetic structures: 18 Micromagnetic modelling: 2 One of the characteristics of the present Colloquium is an increase in the number of presentations in the field of spin-electronics, as seen above. This Cluster Issue of Journal of Physics D: Applied Physics includes several important papers in this rapidly developing field. We believe that, in the future, the field of magnetic materials will maintain its popularity and, on top of that, other fields such as spintronics materials, materials related to life sciences and medicine and also materials related to the environment will be investigated further. The ICMFS Conference started in London in 1964, and is now one of the world-wide conferences on magnetism. The Colloquium has been held in Japan four times now: the previous ones being the 5th ICMFS in the Mount Fuji area, the 10th at Yokohama and the 17th at Kyoto, which was

Predicting thermal history a-priori for magnetic nanoparticle hyperthermia of internal carcinoma

Science.gov (United States)

Dhar, Purbarun; Sirisha Maganti, Lakshmi

2017-08-01

This article proposes a simplistic and realistic method where a direct analytical expression can be derived for the temperature field within a tumour during magnetic nanoparticle hyperthermia. The approximated analytical expression for thermal history within the tumour is derived based on the lumped capacitance approach and considers all therapy protocols and parameters. The present method is simplistic and provides an easy framework for estimating hyperthermia protocol parameters promptly. The model has been validated with respect to several experimental reports on animal models such as mice/rabbit/hamster and human clinical trials. It has been observed that the model is able to accurately estimate the thermal history within the carcinoma during the hyperthermia therapy. The present approach may find implications in a-priori estimation of the thermal history in internal tumours for optimizing magnetic hyperthermia treatment protocols with respect to the ablation time, tumour size, magnetic drug concentration, field strength, field frequency, nanoparticle material and size, tumour location, and so on.

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.

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.

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.

MESSENGER observations of magnetic reconnection in Mercury's magnetosphere.

Science.gov (United States)

Slavin, James A; Acuña, Mario H; Anderson, Brian J; Baker, Daniel N; Benna, Mehdi; Boardsen, Scott A; Gloeckler, George; Gold, Robert E; Ho, George C; Korth, Haje; Krimigis, Stamatios M; McNutt, Ralph L; Raines, Jim M; Sarantos, Menelaos; Schriver, David; Solomon, Sean C; Trávnícek, Pavel; Zurbuchen, Thomas H

2009-05-01

Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between the interplanetary magnetic field (IMF) and a planet's magnetic field. During MESSENGER's second flyby of Mercury, a steady southward IMF was observed and the magnetopause was threaded by a strong magnetic field, indicating a reconnection rate ~10 times that typical at Earth. Moreover, a large flux transfer event was observed in the magnetosheath, and a plasmoid and multiple traveling compression regions were observed in Mercury's magnetotail, all products of reconnection. These observations indicate that Mercury's magnetosphere is much more responsive to IMF direction and dominated by the effects of reconnection than that of Earth or the other magnetized planets.

PREFACE: International Conference on Superconductivity and Magnetism-ICSM2008

Science.gov (United States)

Gencer, Ali; Grasso, Gianni

2009-03-01

The International Conference on Superconductivity and Magnetism (ICSM2008) was held at the congress centre of Ankara University in Side, Antalya, between 25-29 August 2008. The conference was the first conference on the combined fields of superconductivity and magnetism organized in Turkey at international level, and it had broad international participation from 42 countries, with registered delegates numbering over 400. A quarter of the attendees were research students. The conference attracted many of the best known leading scientists and experts in the field of superconductivity and magnetism from all over the world. The scientific program involved the presentation and discussion of 336 papers, classified as 65 invited, 81 oral and 190 posters. Submission of papers for the proceedings was on a volunteer basis and we therefore had nearly half of the presented papers, i.e. 30 submitted invited papers, peer-reviewed by Superconductor Science and Technology, and 85 submitted contributing papers, peer-reviewed by the organizers through processes administered by the Editorial Board and Scientific Committee. Reviews were conducted by expert referees at professional level and with the scientific standards expected of a proceedings journal issue published by IOP Publishing. The invited papers on superconductivity and magnetism with superconductivity were considered and processed for Superconductor Science and Technology by IOP itself. Although there are missing papers from some of the plenary speakers, we believe that this special issue of Superconductor Science and Technology (SUST) and the corresponding issue of Journal of Physics: Conference Series (JPCS) reflect most of the booming research in the fields of superconductivity and magnetism. We are very pleased to have worked with IOP on the conference proceedings, with special thanks to Dr Tom Miller and Dr Graham Douglas. Based on a refereed evaluation of all the papers and posters submitted, about 93 papers were

Magnetic Resonance Imaging With Cochlear Implant Magnet in Place: Safety and Imaging Quality.

Science.gov (United States)

Carlson, Matthew L; Neff, Brian A; Link, Michael J; Lane, John I; Watson, Robert E; McGee, Kiaran P; Bernstein, Matt A; Driscoll, Colin L W

2015-07-01

To evaluate the safety and image quality of 1.5-T MRI in patients with cochlear implants and retained internal magnets. Retrospective case series from 2012 to 2014. Single tertiary academic referral center. All cochlear implant recipients undergoing 1.5-T MRI without internal magnet removal. MRI after tight headwrap application. Patient tolerance, complications, and characteristics of imaging artifact. Nineteen ears underwent a total of 34 MRI scans. Two patients did not tolerate imaging with the headwrap in place and required magnet removal before rescanning. One subject experienced two separate episodes of polarity reversal in the same device from physical realignment (i.e., flipping) of the internal magnet requiring surgical repositioning. Three patients were discovered to have canting of the internal magnet after imaging. In all three cases, the magnet could be reseated by applying gentle firm pressure to the scalp until the magnet "popped" back into place. These patients continue to use their device without difficulty and have not required surgical replacement. In patients receiving head MRI, the ipsilateral internal auditory canal and cerebellopontine angle could be visualized without difficulty in 94% of cases. There were no episodes of cochlear implant device failure or soft tissue complications. Under controlled conditions, 1.5-T MRI can be successfully performed in most patients without the need for cochlear implant magnet removal. In nearly all cases, imaging artifact does not impede evaluation of the ipsilateral skull base. Patients should be counseled regarding the risk of internal magnet movement that may occur in up to 15% of cases, even with tight headwrap application. If internal magnet polarity reversal occurs, a trial of reversing the external magnet can be considered. If canting or mild displacement of the internal magnet occurs, an attempt at reseating can be made by applying gentle firm pressure to the scalp over the internal magnet. If

Biological quarantine on international waters: an initiative for onboard protocols

Science.gov (United States)

Takano, Yoshinori; Yano, Hajime; Funase, Ryu; Sekine, Yasuhito; Takai, Ken

2012-07-01

The research vessel Chikyu is expanding new frontiers in science, technology, and international collaboration through deep-sea expedition. The Chikyu (length: 210 m, gross tonnage: 56752 tons) has advanced and comprehensive scientific research facilities. One of the scientific purposes of the vessel is to investigate into unexplored biosphere (i.e., undescribed extremophiles) on the Earth. Therefore, "the onboard laboratory" provides us systematic microbiological protocols with a physical containment situation. In parallel, the onboard equipments provide sufficient space for fifty scientists and technical support staff. The helicopter deck also supports various logistics through transporting by a large scale helicopter (See, http://www.jamstec.go.jp/chikyu/eng/). Since the establishment of Panel on Planetary Protection (PPP) in Committee on Space Research (COSPAR), we have an international consensus about the development and promulgation of planetary protection knowledge, policy, and plans to prevent the harmful effects of biological contamination on the Earth (e.g., Rummel, 2002). However, the matter to select a candidate location of initial quarantine at BSL4 level is often problematic. To answer the key issue, we suggest that international waters can be a meaningful option with several advantages to conduct initial onboard-biological quarantine investigation. Hence, the research vessel Chikyu is promising for further PPP requirements (e.g., Enceladus sample return project: Tsou et al., 2012). Rummel, J., Seeking an international consensus in planetary protection: COSPAR's planetary protection panel. Advances in Space Research, 30, 1573-1575 (2002). Tsou, P. et al. LIFE: Life Investigation For Enceladus - A Sample Return Mission Concept in Search for Evidence of Life. Astrobiology, in press.

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.

IMPEx : enabling model/observational data comparison in planetary plasma sciences

Science.gov (United States)

Génot, V.; Khodachenko, M.; Kallio, E. J.; Al-Ubaidi, T.; Alexeev, I. I.; Topf, F.; Gangloff, M.; André, N.; Bourrel, N.; Modolo, R.; Hess, S.; Perez-Suarez, D.; Belenkaya, E. S.; Kalegaev, V.

2013-09-01

The FP7 IMPEx infrastructure, whose general goal is to encourage and facilitate inter-comparison between observational and model data in planetary plasma sciences, is now established for 2 years. This presentation will focus on a tour of the different achievements which occurred during this period. Within the project, data originate from multiple sources : large observational databases (CDAWeb, AMDA at CDPP, CLWeb at IRAP), simulation databases for hybrid and MHD codes (FMI, LATMOS), planetary magnetic field models database and online services (SINP). Each of these databases proposes dedicated access to their models and runs (HWA@FMI, LATHYS@LATMOS, SMDC@SINP). To gather this large data ensemble, IMPEx offers a distributed framework in which these data may be visualized, analyzed, and shared thanks to interoperable tools; they comprise of AMDA - an online space physics analysis tool -, 3DView - a tool for data visualization in 3D planetary context -, and CLWeb - an online space physics visualization tool. A simulation data model, based on SPASE, has been designed to ease data exchange within the infrastructure. On the communication point of view, the VO paradigm has been retained and the architecture is based on web services and the IVOA protocol SAMP. The presentation will focus on how the tools may be operated synchronously to manipulate these heterogeneous data sets. Use cases based on in-flight missions and associated model runs will be proposed for the demonstration. Finally the motivation and functionalities of the future IMPEx portal will be exposed. As requirements to and potentialities of joining the IMPEx infrastructure will be shown, the presentation could be seen as an invitation to other modeling teams in the community which may be interested to promote their results via IMPEx.

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

Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines

Energy Technology Data Exchange (ETDEWEB)

Misguich, J.H.; Reuss, J.D. [Association Euratom-CEA sur la Fusion, CEA/DSM/DRFC, 13 - Saint Paul lez Durance (France); Constantinescu, D.; Steinbrecher, G. [Association Euratom-N.A.S.T.I., Dept. of Physics, University of Craiova (Romania); Vlad, M.; Spineanu, F. [Association Euratom-N.A.S.T.I., National Institute of Laser, Plasma and Radiation Physics, Bucharest (Romania); Weyssow, B.; Balescu, R. [Association Euratom-Etat Belge sur la Fusion, Universite Libre de Bruxelles (Belgium)

2002-02-01

Internal transport barriers (ITB's) observed in tokamaks are described by a purely magnetic approach. Magnetic line motion in toroidal geometry with broken magnetic surfaces is studied from a previously derived Hamiltonian map in situation of incomplete chaos. This appears to reproduce in a realistic way the main features of a tokamak, for a given safety factor profile and in terms of a single parameter L representing the amplitude of the magnetic perturbation. New results are given concerning the Shafranov shift as function of L. For small values of L, closed magnetic surfaces exist (KAM tori) and island chains begin to appear on rational surfaces for higher values of L, with chaotic zones around hyperbolic points, as expected. Single trajectories of magnetic line motion indicate the persistence of a central protected plasma core, surrounded by a chaotic shell enclosed in a double-sided transport barrier. Magnetic lines which succeed to escape across this barrier begin to wander in a wide chaotic sea extending up to a very robust barrier (as long as L{<=}1). For values of L{>=}1, above the escape threshold, most magnetic lines succeed to escape out of the external barrier which has become a permeable Cantorus. Statistical analysis of a large number of trajectories, representing the evolution of a bunch of magnetic lines, indicate that the flux variable {psi} asymptotically grows in a diffuse manner as (L{sup 2}t) with a L{sup 2} scaling as expected, but that the average radial position r{sub m}(t) asymptotically grows as (L{sup 2}t){sup 1/4} while the mean square displacement around this average radius asymptotically grows in a sub-diffusive manner as (L{sup 2}t){sup 1/2}. This result shows the slower dispersion in the present incomplete chaotic regime, which is different from the usual quasilinear diffusion in completely chaotic situations. For physical times t{sub {phi}} of the order of the escape time defined by x{sub m}(t{sub {phi}}) {approx}1, the motion

Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines

International Nuclear Information System (INIS)

Misguich, J.H.; Reuss, J.D.; Constantinescu, D.; Steinbrecher, G.; Vlad, M.; Spineanu, F.; Weyssow, B.; Balescu, R.

2002-02-01

Internal transport barriers (ITB's) observed in tokamaks are described by a purely magnetic approach. Magnetic line motion in toroidal geometry with broken magnetic surfaces is studied from a previously derived Hamiltonian map in situation of incomplete chaos. This appears to reproduce in a realistic way the main features of a tokamak, for a given safety factor profile and in terms of a single parameter L representing the amplitude of the magnetic perturbation. New results are given concerning the Shafranov shift as function of L. For small values of L, closed magnetic surfaces exist (KAM tori) and island chains begin to appear on rational surfaces for higher values of L, with chaotic zones around hyperbolic points, as expected. Single trajectories of magnetic line motion indicate the persistence of a central protected plasma core, surrounded by a chaotic shell enclosed in a double-sided transport barrier. Magnetic lines which succeed to escape across this barrier begin to wander in a wide chaotic sea extending up to a very robust barrier (as long as L≤1). For values of L≥1, above the escape threshold, most magnetic lines succeed to escape out of the external barrier which has become a permeable Cantorus. Statistical analysis of a large number of trajectories, representing the evolution of a bunch of magnetic lines, indicate that the flux variable ψ asymptotically grows in a diffuse manner as (L 2 t) with a L 2 scaling as expected, but that the average radial position r m (t) asymptotically grows as (L 2 t) 1/4 while the mean square displacement around this average radius asymptotically grows in a sub-diffusive manner as (L 2 t) 1/2 . This result shows the slower dispersion in the present incomplete chaotic regime, which is different from the usual quasilinear diffusion in completely chaotic situations. For physical times t φ of the order of the escape time defined by x m (t φ ) ∼1, the motion appears to be super-diffusive, however, but less dangerous than

Design considerations for ITER [International Thermonuclear Experimental Reactor] magnet systems

International Nuclear Information System (INIS)

Henning, C.D.; Miller, J.R.

1988-01-01

The International Thermonuclear Experimental Reactor (ITER) is now completing a definition phase as a beginning of a three-year design effort. Preliminary parameters for the superconducting magnet system have been established to guide further and more detailed design work. Radiation tolerance of the superconductors and insulators has been of prime importance, since it sets requirements for the neutron-shield dimension and sensitively influences reactor size. The major levels of mechanical stress in the structure appear in the cases of the inboard legs of the toroidal-field (TF) coils. The cases of the poloidal-field (PF) coils must be made thin or segmented to minimize eddy current heating during inductive plasma operation. As a result, the winding packs of both the TF and PF coils includes significant fractions of steel. The TF winding pack provides support against in-plane separating loads but offers little support against out-of-plane loads, unless shear-bonding of the conductors can be maintained. The removal of heat due to nuclear and ac loads has not been a fundamental limit to design, but certainly has non-negligible economic consequences. We present here preliminary ITER magnetic systems design parameters taken from trade studies, designs, and analyses performed by the Home Teams of the four ITER participants, by the ITER Magnet Design Unit in Garching, and by other participants at workshops organized by the Magnet Design Unit. The work presented here reflects the efforts of many, but the responsibility for the opinions expressed is the authors'. 4 refs., 3 figs., 4 tabs

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.

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.

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.

PREFACE: 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3)

Science.gov (United States)

Sakka, Yoshio; Hirota, Noriyuki; Horii, Shigeru; Ando, Tsutomu

2009-07-01

The 3rd International Workshop on Materials Analysis and Processing in Materials Fields (MAP3) was held on 14-16 May 2008 at the University of Tokyo, Japan. The first was held in March 2004 at the National High Magnetic Field Laboratory in Tallahassee, USA. Two years later the second took place in Grenoble, France. MAP3 was held at The University of Tokyo International Symposium, and jointly with MANA Workshop on Materials Processing by External Stimulation, and JSPS CORE Program of Construction of the World Center on Electromagnetic Processing of Materials. At the end of MAP3 it was decided that the next MAP4 will be held in Atlanta, USA in 2010. Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. MAP3 focused on the magnetic field interactions involved in the study and processing of materials in all disciplines ranging from physics to chemistry and biology: Magnetic field effects on chemical, physical, and biological phenomena Magnetic field effects on electrochemical phenomena Magnetic field effects on thermodynamic phenomena Magnetic field effects on hydrodynamic phenomena Magnetic field effects on crystal growth Magnetic processing of materials Diamagnetic levitation Magneto-Archimedes effect Spin chemistry Application of magnetic fields to analytical chemistry Magnetic orientation Control of structure by magnetic fields Magnetic separation and purification Magnetic field-induced phase transitions Materials properties in high magnetic fields Development of NMR and MRI Medical application of magnetic fields Novel magnetic phenomena Physical property measurement by Magnetic fields High magnetic field generation> MAP3 consisted of 84 presentations including 16 invited talks. This volume of Journal of Physics: Conference Series contains the proceeding of MAP3 with 34 papers that provide a scientific record of the topics covered by the conference with the special topics (13 papers) in

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

Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field.

Science.gov (United States)

Johnson, Catherine L; Phillips, Roger J; Purucker, Michael E; Anderson, Brian J; Byrne, Paul K; Denevi, Brett W; Feinberg, Joshua M; Hauck, Steven A; Head, James W; Korth, Haje; James, Peter B; Mazarico, Erwan; Neumann, Gregory A; Philpott, Lydia C; Siegler, Matthew A; Tsyganenko, Nikolai A; Solomon, Sean C

2015-05-22

Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data. Copyright © 2015, American Association for the Advancement of Science.

Comparative Magnetic Minima: Characterizing Quiet Times in the Sun and Stars. Symposium of the International Astronomical Union (286th) Held in Mendoza, Argentina on October 3-7, 2011

Science.gov (United States)

2011-10-01

11:15 – 11:45 Invited Talk – Stars in Magnetic Grand Minima: Where Are They and What Are They Like? Steven Saar (Presentation file) 11:45 – 12:00...of Archaeology and Ancient History, University Rd, Leicester LE1 7RH, United Kingdom IAUS 279 Death of Massive Stars: Supernovae and Gamma-Ray Bursts...of Astronomy & Astrophysics, 525 Davey Lab, University Park, PA 16802, USA IAUS 283 Planetary Nebulae: an Eye to the Future A. MANCHADO, Instituto de

On the parametrization of the planetary boundary layer of the atmosphere

Energy Technology Data Exchange (ETDEWEB)

Yordanov, D. [Bulgarian Academy of Sciences, Geophysical Inst., Sofia (Bulgaria); Syrakov, D.; Kolarova, M. [Bulgarian Academy of Sciences, National Inst. of Meteorology and Hydrology, Sofia (United Kingdom)

1997-10-01

The investigation of the dynamic processes in the planetary boundary layer presents a definite theoretical challenge and plays a growing role for the solution of a number of practical tasks. The improvement of large-scale atmospheric weather forecast depends, to a certain degree, on the proper inclusion of the planetary boundary layer dynamics in the numerical models. The modeling of the transport and the diffusion of air pollutants is connected with estimation of the different processes in the Planetary Boundary Layer (PBL) and needs also a proper PBL parametrization. For the solution of these practical tasks the following PBL models;(i) a baroclinic PBL model with its barotropic version, and (ii) a convective PBL model were developed. Both models are one dimensional and are based on the similarity theory and the resistance lows extended for the whole PBL. Two different PBL parametrizations under stable and under convective conditions are proposed, on the basis of which the turbulent surface heat and momentum fluxes are estimated using generalized similarity theory. By the proposed parametrizations the internal parameters are calculated from the synoptic scale parameters as geostrophyc wind, potential temperature and humidity given at two levels (ground level and at 850 hPa) and from them - the PBL profiles. The models consists of two layers: a surface layer (SL) with a variable height and a second (Ekman layer) over it with a constant with height turbulent exchange coefficient. (au) 14 refs.

A Path to Planetary Protection Requirements for Human Exploration: A Literature Review and Systems Engineering Approach

Science.gov (United States)

Johnson, James E.; Conley, Cassie; Siegel, Bette

2015-01-01

As systems, technologies, and plans for the human exploration of Mars and other destinations beyond low Earth orbit begin to coalesce, it is imperative that frequent and early consideration is given to how planetary protection practices and policy will be upheld. While the development of formal planetary protection requirements for future human space systems and operations may still be a few years from fruition, guidance to appropriately influence mission and system design will be needed soon to avoid costly design and operational changes. The path to constructing such requirements is a journey that espouses key systems engineering practices of understanding shared goals, objectives and concerns, identifying key stakeholders, and iterating a draft requirement set to gain community consensus. This paper traces through each of these practices, beginning with a literature review of nearly three decades of publications addressing planetary protection concerns with respect to human exploration. Key goals, objectives and concerns, particularly with respect to notional requirements, required studies and research, and technology development needs have been compiled and categorized to provide a current 'state of knowledge'. This information, combined with the identification of key stakeholders in upholding planetary protection concerns for human missions, has yielded a draft requirement set that might feed future iteration among space system designers, exploration scientists, and the mission operations community. Combining the information collected with a proposed forward path will hopefully yield a mutually agreeable set of timely, verifiable, and practical requirements for human space exploration that will uphold international commitment to planetary protection.

Fourth International Conference on Nanoscale Magnetism

CERN Document Server

Aktas, Bekir; Advances in Nanoscale Magnetism

2009-01-01

The book aims to provide an overview of recent progress in the understanding of magnetic properties in nanoscale through recent results of various theoretical and experimental investigations. The papers describe a wide range of physical aspects, together with theoretical and experimental methods. It is of central interest to researchers and specialists in magnetism and magnetic materials science, both in academic and industrial research, as well as advanced students.

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.

Electron Dynamics in a Subproton-Gyroscale Magnetic Hole

Science.gov (United States)

Gershman, Daniel J.; Dorelli, John C.; Vinas, Adolfo F.; Avanov, Levon A.; Gliese, Ulrik B.; Barrie, Alexander C.; Coffey, Victoria; Chandler, Michael; Dickson, Charles; MacDonald, Elizabeth A.;

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.

Structure of the solar nebula, growth and decay of magnetic fields and effects of magnetic and turbulent viscosities on the nebula

International Nuclear Information System (INIS)

Hayashi, Chushiro

1982-01-01

First, distributions of surface densities of dust materials and gases in a preplanetary solar nebula, which give a good fit to the distribution of the planetary mass, are presented and the over-all structure of this nebula, which is in thermal and gravitational equilibrium, is studied. Second, in order to see magnetic effect on the structure, electric conductivity of a gas ionized by cosmic rays and radioactivities contained in dust grains is estimated for each region of the nebula and, then, the growth and decay of seed magnetic fields, which are due to differential rotation of the nebula and to the Joule dissipation, respectively, are calculated. The results indicate that, in regions of the terrestrial planets, magnetic fields decay much faster than they grow and magnetic effects can be ignored, except for the outermost layers of very low density. This is not the case for regions of Uranus and Neptune where magnetic fields can be amplified to considerable extents. Third, the transport of angular momentum due to magnetic and mechanical turbulent viscosities and the resultant redistribution of surface density in the nebula are investigated. The results show that the density redistribution occurs, in general, in a direction to attain a distribution of surface density which has nearly the same ν-dependence as that obtained from the present distribution of the planetary mass. This redistribution seems to be possible if it occurs at a formation stage of the nebula where the presence of large viscosities is expected. Finally, a comment is given on the initial condition of a collapsing interstellar cloud from which the solar nebula is formed at the end of the collapse. (author)

Model/observational data cross analysis in planetary plasma sciences with IMPEx

Science.gov (United States)

Genot, V. N.; Khodachenko, M.; Kallio, E. J.; Al-Ubaidi, T.; Alexeev, I. I.; Gangloff, M.; Bourrel, N.; andre, N.; Modolo, R.; Hess, S.; Topf, F.; Perez-Suarez, D.; Belenkaya, E. S.; Kalegaev, V. V.; Hakkinen, L. V.

2013-12-01

This presentation details how the FP7 IMPEx (http://impex-fp7.oeaw.ac.at/) infrastructure helps scientists in inter-comparing observational and model data in planetary plasma sciences. Within the project, data originate from multiple sources : large observational databases (CDAWeb, AMDA at CDPP, CLWeb at IRAP), simulation databases for hybrid and MHD codes (FMI, LATMOS), planetary magnetic field models database and online services (SINP). To navigate in this large data ensemble, IMPEx offers a distributed framework in which these data may be visualized, analyzed, and shared thanks to a set of interoperable tools (AMDA, 3DView, CLWeb). A simulation data model, based on SPASE, has been designed to ease data exchange within the infrastructure. On the communication point of view, the Virtual Observatory paradigm is followed and the architecture is based on web services and the IVOA protocol SAMP. These choices enabled a high level versatility with the goal to allow other model or data providers to distribute their own resources via the IMPEx infrastructure. A detailed use case based on Mars data and hybrid models will be proposed showing how the tools may be operated synchronously to manipulate heterogeneous data sets. Facilitating the analysis of the future MAVEN observations is one possible application of the IMPEx infrastructure.

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

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

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

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

Internal transport barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.; Challis, C.D.; Conway, G.D.

2003-01-01

The formation of Internal Transport Barriers (ITBs) has been experimentally associated with the presence of rational q-surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling or fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable to the linear growth rate of ITG modes. For JET reversed magnetic shear scenarios, ITB emergence occurs preferentially when the minimum q reaches an integer value. In this case, transport effects localised in the vicinity of zero magnetic shear and close to rational q values may also contribute to the formation of ITBs.The role of rational q surfaces on ITB triggering stresses the importance of q profile control for advanced tokamak scenario and could contribute to lower substantially the access power to these scenarios in next step facilities. (author)

Internal Transport Barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.H.

2002-01-01

The formation of Internal Transport Barriers (ITBs) has been experimentally associated with the presence of rational q-surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling or fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable to the linear growth rate of ITG modes. For reversed magnetic shear scenario, ITB emergence occurs preferentially when the minimum q reaches an integer value. In this case, transport effects localised in the vicinity of zero magnetic shear and close to rational q values may also contribute to the formation of ITBs. The role of rational q surfaces on ITB triggering stresses the importance of q profile control for advanced tokamak scenario and could contribute to lower substantially the access power to these scenarios in next step facilities. (author)

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.

The earth's palaeomagnetosphere as the third type of planetary magnetosphere

International Nuclear Information System (INIS)

Saito, T; Sakurai, T.; Yumoto, K.

1978-01-01

From the viewpoint of dynamical topology, planetary magnetospheres are classified into three: Types 1,2 and 3. When the rotation vector and dipole moment of a planet and the velocity vector of the solar wind are denoted as Ω,M, and V, respectively, the planetary magnetosphere with Ωparallel to M perpendicular to V is called Type 1. The magnetospheres of the present Earth, Jupiter, and Uranus at its equinoctial points belong to this type. The magnetosphere with Ωparallel to M parallel to V is called Type 2, which includes the Uranium magnetosphere at its solstitial points. The magnetosphere with Ωperpendicular M and perpendicular V is called Type 3. The Earth's palaeomagnetosphere is considered to have experienced Type 3 during excursions and transition stages of palaeomagnetic polarity reversals. In the Type 3 magnetosphere, drastic variations are expected in configurations of the dayside cusps, tail axis, neutral sheet, polar caps, and so on. A possible relation between the Type 3 palaeomagnetosphere and palaeoclimate of the Earth during polarity reversals and geomagnetic excursions is suggested. It is also suggested that the heliomagnetosphere during polarity reversals of the general field of the Sun exhibits a drastic configuration change similar to the Type 3 palaeomagnetosphere of the Earth. A relation between the perpendicular condition Ω perpendicular to M and magnetic variable stars and pulsars is briefly discussed. (author)

Exploring the planetary boundary for chemical pollution.

Science.gov (United States)

Diamond, Miriam L; de Wit, Cynthia A; Molander, Sverker; Scheringer, Martin; Backhaus, Thomas; Lohmann, Rainer; Arvidsson, Rickard; Bergman, Åke; Hauschild, Michael; Holoubek, Ivan; Persson, Linn; Suzuki, Noriyuki; Vighi, Marco; Zetzsch, Cornelius

2015-05-01

Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social

Instrumented Moles for Planetary Subsurface Regolith Studies

Science.gov (United States)

Richter, L. O.; Coste, P. A.; Grzesik, A.; Knollenberg, J.; Magnani, P.; Nadalini, R.; Re, E.; Romstedt, J.; Sohl, F.; Spohn, T.

2006-12-01

Soil-like materials, or regolith, on solar system objects provide a record of physical and/or chemical weathering processes on the object in question and as such possess significant scientific relevance for study by landed planetary missions. In the case of Mars, a complex interplay has been at work between impact gardening, aeolian as well as possibly fluvial processes. This resulted in regolith that is texturally as well as compositionally layered as hinted at by results from the Mars Exploration Rover (MER) missions which are capable of accessing shallow subsurface soils by wheel trenching. Significant subsurface soil access on Mars, i.e. to depths of a meter or more, remains to be accomplished on future missions. This has been one of the objectives of the unsuccessful Beagle 2 landed element of the ESA Mars Express mission having been equipped with the Planetary Underground Tool (PLUTO) subsurface soil sampling Mole system capable of self-penetration into regolith due to an internal electro-mechanical hammering mechanism. This lightweight device of less than 900 g mass was designed to repeatedly obtain and deliver to the lander regolith samples from depths down to 2 m which would have been analysed for organic matter and, specifically, organic carbon from potential extinct microbial activity. With funding from the ESA technology programme, an evolved Mole system - the Instrumented Mole System (IMS) - has now been developed to a readiness level of TRL 6. The IMS is to serve as a carrier for in situ instruments for measurements in planetary subsurface soils. This could complement or even eliminate the need to recover samples to the surface. The Engineering Model hardware having been developed within this effort is designed for accommodating a geophysical instrument package (Heat Flow and Physical Properties Package, HP3) that would be capable of measuring regolith physical properties and planetary heat flow. The chosen design encompasses a two-body Mole

Alpha Magnetic Spectrometer (AMS) for Extraterrestrial Study of Antimatter, Matter and Missing Matter on the International Space Station

CERN Multimedia

Lee, M W; Lipari, P; Berdugo perez, J F; Borgia, B; Lazzizzera, I; Battarbee, M C; Valente, V; Bartoloni, A

2002-01-01

% RE1\\\\ \\\\ AMS is the first magnetic particle physics spectrometer to be installed on the International Space Station. With a superconducting magnetic spectrometer, AMS will provide accurate measurements of electrons, positrons, protons, antiprotons and various nuclei up to TeV region. NASA has scheduled to install this detector on the International Space Station in May 2003. The first flight of AMS was done with a permanent magnet and this prototype detector has provided accurate information on the limit of the existence of antihelium. It also showed that proton and electron -positron spectra exhibited a complicated behavior in the near earth orbit. The construction of AMS is being carried out in Switzerland, Germany, Italy, France, Finland, Spain, Portugal, Romania, Russia, Taiwan, China and the United States. NASA provides the use of the space shuttle and the space station, as well as mission management.

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.

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

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.

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.

THERMAL EVOLUTION AND LIFETIME OF INTRINSIC MAGNETIC FIELDS OF SUPER-EARTHS IN HABITABLE ZONES

International Nuclear Information System (INIS)

Tachinami, C.; Ida, S.; Senshu, H.

2011-01-01

We have numerically studied the thermal evolution of different-mass terrestrial planets in habitable zones, focusing on the duration of dynamo activity to generate their intrinsic magnetic fields, which may be one of the key factors in habitability of the planets. In particular, we are concerned with super-Earths, observations of which are rapidly developing. We calculated the evolution of temperature distributions in the planetary interior using Vinet equations of state, the Arrhenius-type formula for mantle viscosity, and the astrophysical mixing-length theory for convective heat transfer modified for mantle convection. After calibrating the model with terrestrial planets in the solar system, we apply it for 0.1-10 M + rocky planets with a surface temperature of 300 K (in habitable zones) and Earth-like compositions. With the criterion of heat flux at the core-mantle boundary (CMB), the lifetime of the magnetic fields is evaluated from the calculated thermal evolution. We found that the lifetime slowly increases with planetary mass (M p ), independent of the initial temperature gap at the CMB (ΔT CMB ), but beyond the critical value M c,p (∼O(1) M + ) it abruptly declines from the mantle viscosity enhancement due to the pressure effect. We derived M c,p as a function of ΔT CMB and a rheological parameter (activation volume, V*). Thus, the magnetic field lifetime of super-Earths with M p >M p,c sensitively depends on ΔT CMB , which reflects planetary accretion, and V*, which has uncertainty at very high pressure. More advanced high-pressure experiments and first-principle simulation, as well as planetary accretion simulation, are needed to discuss the habitability of super-Earths.

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.

Experiments in Ice Contaminant Remanent Magnetization of Dusty Frost Deposits

Science.gov (United States)

Grossman, Y.; Aharonson, O.; Shaar, R.

2017-12-01

Sedimentary rocks can acquire magnetization in the presence of an external field as grains settle out of suspension in a water column - a process known as Depositional Remanent Magnetization (DRM). In analogy with this, here we propose and experimentally demonstrate a new mechanism for acquisition of magnetization by ice and particulate mixtures which we term Ice Contaminant Remanent Magnetization (ICRM). This phenomenon results from the settling of atmospheric dust containing magnetic particles (e.g. magnetite or other iron oxides). Upon freezing, magnetic dust particles assume a preferential orientation that depends on the external planetary field, resulting in bulk magnetization of the dusty ice. Hence over geologic timescales, the ice stratigraphy is expected to record the geomagnetic history. To test this hypothesis, we designed a set of experiments in which mixtures of ice and dust were deposited in a controlled ambient magnetic field environment. We measured the ratio between the volume normalized magnetization of the dusty ice (m) and the applied field (H) during deposition of the mixture, which is expressed as the effective ICRM susceptibility: m=χICRMH. A magnetic field was applied by a 3-axis Helmholtz coil at the Weizmann Simulating Planetary Ices & Environments Laboratory, and the frozen samples were analyzed in a 2G-Entreprises SQUID Rock Magnetometer at the Hebrew University Institute for Earth Sciences. We measured a clear correlation in amplitude and direction between the ambient magnetic field applied during deposition and the remanent magnetic moment of the resulting samples. We studied various concentrations and particle sizes (diameters 5 µm to 50 µm) of iron and magnetite particles. Effective bulk susceptibilities show a range of values, starting from 10-3 and up to values that saturate the analytical instrument. Our preliminary results indicate that natural ice deposits may acquire variable magnetization due to ICRM, which may in turn be

On the control of magnetic perturbing field onboard landers: the Magnetometer Protection program for the ESA ExoMars/Humboldt MSMO magnetometer experiment

DEFF Research Database (Denmark)

Menvielle, M.; Primdahl, Fritz; Brauer, Peter

to planetary research. The major difficulty in implementing a magnetometer experiment onboard a lander is to achieve at acceptable costs a good Magnetometer Protection, namely to control the perturbing magnetic field generated by the lander during operations at the planetary surfa ce, so as to achieve...... scientific payload in the frame of the ESA ExoMars mission. Experience from previous missions constitutes the background for the MSMO Magnetometer Protection strategy. DC and AC lander generated magnetic perturbations are discussed, with particular attention to those related to solar generators. Emphasis...... and very resource consuming....

Toroidal equilibrium states with reversed magnetic shear and parallel flow in connection with the formation of Internal Transport Barriers

Science.gov (United States)

Kuiroukidis, Ap.; Throumoulopoulos, G. N.

2015-08-01

We construct nonlinear toroidal equilibria of fixed diverted boundary shaping with reversed magnetic shear and flows parallel to the magnetic field. The equilibria have hole-like current density and the reversed magnetic shear increases as the equilibrium nonlinearity becomes stronger. Also, application of a sufficient condition for linear stability implies that the stability is improved as the equilibrium nonlinearity correlated to the reversed magnetic shear gets stronger with a weaker stabilizing contribution from the flow. These results indicate synergetic stabilizing effects of reversed magnetic shear, equilibrium nonlinearity and flow in the establishment of Internal Transport Barriers (ITBs).

Single rotating stars and the formation of bipolar planetary nebula

Energy Technology Data Exchange (ETDEWEB)

García-Segura, G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Km. 103 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico); Villaver, E. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Langer, N. [Argelander-Institut für Astronomie, Universität Bonn, D-53121 Bonn (Germany); Yoon, S.-C. [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of); Manchado, A., E-mail: ggs@astrosen.unam.mx [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38200 La Laguna, Tenerife (Spain)

2014-03-10

We have computed new stellar evolution models that include the effects of rotation and magnetic torques under different hypotheses. The goal is to test whether a single star can sustain the rotational velocities needed in the envelope for magnetohydrodynamical(MHD) simulations to shape bipolar planetary nebulae (PNe) when high mass-loss rates take place. Stellar evolution models with main sequence masses of 2.5 and 5 M {sub ☉} and initial rotational velocities of 250 km s{sup –1} have been followed through the PNe formation phase. We find that stellar cores have to be spun down using magnetic torques in order to reproduce the rotation rates observed for white dwarfs. During the asymptotic giant branch phase and beyond, the magnetic braking of the core has a practically null effect on increasing the rotational velocity of the envelope since the stellar angular momentum is efficiently removed by the wind. We have also tested the best possible case scenarios in rather non-physical contexts to give enough angular momentum to the envelope. We find that we cannot get the envelope of a single star to rotate at the speeds needed for MHD simulations to form bipolar PNe. We conclude that single stellar rotators are unlikely to be the progenitors of bipolar PNe under the current MHD model paradigm.

Design and construction of permanent magnetic gears

DEFF Research Database (Denmark)

Jørgensen, Frank Thorleif

/l]. Measurement from this gear has resulted in a measured total torque density of 23 [Nm/l]. Mechanical versions of this gear type are found with total torque density in the 16 to 31 [Nm/l] range. The third and last gear technology that is investigated is a gear that reminds of a planetary gear. Research shows......This thesis deals with design and development of permanent magnetic gears. The goal of this thesis is to develop knowledge and calculation software for magnetic gears. They use strong NdFeB permanent magnets and a new magnetic gear technology, which will be a serious alternative to classical...... mechanical gears. The new magnetic gear will have a high torque density1 relationship –high efficiency and are maintenance free. In this project was manufactured two test gears which is tested and verified with models developed in this project. Present technological status for magnetic gears is introduced...

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.

Free and Open Source Software for Geospatial in the field of planetary science

Science.gov (United States)

Frigeri, A.

2012-12-01

Information technology applied to geospatial analyses has spread quickly in the last ten years. The availability of OpenData and data from collaborative mapping projects increased the interest on tools, procedures and methods to handle spatially-related information. Free Open Source Software projects devoted to geospatial data handling are gaining a good success as the use of interoperable formats and protocols allow the user to choose what pipeline of tools and libraries is needed to solve a particular task, adapting the software scene to his specific problem. In particular, the Free Open Source model of development mimics the scientific method very well, and researchers should be naturally encouraged to take part to the development process of these software projects, as this represent a very agile way to interact among several institutions. When it comes to planetary sciences, geospatial Free Open Source Software is gaining a key role in projects that commonly involve different subjects in an international scenario. Very popular software suites for processing scientific mission data (for example, ISIS) and for navigation/planning (SPICE) are being distributed along with the source code and the interaction between user and developer is often very strict, creating a continuum between these two figures. A very widely spread library for handling geospatial data (GDAL) has started to support planetary data from the Planetary Data System, and recent contributions enabled the support to other popular data formats used in planetary science, as the Vicar one. The use of Geographic Information System in planetary science is now diffused, and Free Open Source GIS, open GIS formats and network protocols allow to extend existing tools and methods developed to solve Earth based problems, also to the case of the study of solar system bodies. A day in the working life of a researcher using Free Open Source Software for geospatial will be presented, as well as benefits and

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…

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.

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.

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

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

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...

Internal transport barrier triggering by rational magnetic flux surfaces in tokamaks

International Nuclear Information System (INIS)

Joffrin, E.; Challis, C.D.; Conway, G.D.

2003-01-01

The formation of internal transport barriers (ITBs) has been experimentally associated with the presence of rational q surfaces in both JET and ASDEX Upgrade. The triggering mechanisms are related to the occurrence of magneto-hydrodynamic (MHD) instabilities such as mode coupling and fishbone activity. These events could locally modify the poloidal velocity and increase transiently the shearing rate to values comparable with the linear growth rate of ion temperature gradient modes. For JET reversed magnetic shear scenarios, ITB emergence occurs preferentially when the minimum q reaches an integral value. In this case, transport effects localized in the vicinity of zero magnetic shear and close to rational q values may be at the origin of ITB formation. The role of rational q surfaces in ITB triggering stresses the importance of q profile control for an advanced tokamak scenario and could assist in substantially lowering the access power to these scenarios in next step facilities. (author)

Partnering to Enhance Planetary Science Education and Public Outreach Programs

Science.gov (United States)

Dalton, H.; Shipp, S. S.; Shupla, C. B.; Shaner, A. J.; LaConte, K.

2015-12-01

The Lunar and Planetary Institute (LPI) in Houston, Texas utilizes many partners to support its multi-faceted Education and Public Outreach (E/PO) program. The poster will share what we have learned about successful partnerships. One portion of the program is focused on providing training and NASA content and resources to K-12 educators. Teacher workshops are performed in several locations per year, including LPI and the Harris County Department of Education, as well as across the country in cooperation with other programs and NASA Planetary Science missions. To serve the public, LPI holds several public events per year called Sky Fest, featuring activities for children, telescopes for night sky viewing, and a short scientist lecture. For Sky Fest, LPI partners with the NASA Johnson Space Center Astronomical Society; they provide the telescopes and interact with members of the public as they are viewing celestial objects. International Observe the Moon Night (InOMN) is held annually and involves the same aspects as Sky Fest, but also includes partners from Johnson Space Center's Astromaterials Research and Exploration Science group, who provide Apollo samples for the event. Another audience that LPI E/PO serves is the NASA Planetary Science E/PO community. Partnering efforts for the E/PO community include providing subject matter experts for professional development workshops and webinars, connections to groups that work with diverse and underserved audiences, and avenues to collaborate with groups such as the National Park Service and the Afterschool Alliance. Additional information about LPI's E/PO programs can be found at http://www.lpi.usra.edu/education. View a list of LPI E/PO's partners here: http://www.lpi.usra.edu/education/partners/.

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

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

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...

Annual review of earth and planetary sciences. Volume 16

International Nuclear Information System (INIS)

Wetherill, G.W.; Albee, A.L.; Stehli, F.G.

1988-01-01

Various papers on earth and planetary science topics are presented. The subjects addressed include: role and status of earth science field work; phase relations of prealuminous granitic rocks and their petrogenetic implications; chondritic meteorites and the solar nebula; volcanic winters; mass wasting on continental margins; earthquake ground motions; ore deposits as guides to geologic history of the earth; geology of high-level nuclear waste disposal; and tectonic evolution of the Caribbean. Also discussed are: the earth's rotation; the geophysics of a restless caldera (Long Valley, California); observations of cometary nuclei; geology of Venus; seismic stratigraphy; in situ-produced cosmogenic isotopes in terrestrial rocks; time variations of the earth's magnetic field; deep slabs, geochemical heterogeneity, and the large-scale structure of mantle convection; early proterozoic assembly and growth of Laurentia; concepts and methods of high-resolution event stratigraphy

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.

In-Flight spacecraft magnetic field monitoring using scalar/vector gradiometry

DEFF Research Database (Denmark)

Primdahl, Fritz; Risbo, Torben; Merayo, José M.G.

2006-01-01

Earth magnetic field mapping from planetary orbiting satellites requires a spacecraft magnetic field environment control program combined with the deployment of the magnetic sensors on a boom in order to reduce the measurement error caused by the local spacecraft field. Magnetic mapping missions...... (Magsat, Oersted, CHAMP, SAC-C MMP and the planned ESA Swarm project) carry a vector magnetometer and an absolute scalar magnetometer for in-flight calibration of the vector magnetometer scale values and for monitoring of the inter-axes angles and offsets over time intervals from months to years...... sensors onboard the Oersted satellite. For Oersted, a large difference between the pre-flight determined spacecraft magnetic field and the in-flight estimate exists causing some concern about the general applicability of the dual sensors technique....

Decreasing the radiation quality factor of magnetic dipole antennas by a magnetic-coated metal core

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Breinbjerg, Olav

2010-01-01

To achieve the Chu lower bound for the radiation Q, an electrically small magnetic dipole antenna should not store any magnetic energy internally to the minimum sphere enclosing the antenna. As shown in our previous works, the internal stored magnetic energy can be reduced, although not entirely...... eliminated, by introducing a solid magnetic core inside the antenna. In this paper, using analytical results obtained though the vector spherical wave theory, we show that the internal stored magnetic energy can be further reduced, and the Chu lower bound reached, for a spherical magnetic dipole antenna...

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.

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.

Public Engagement with the Lunar and Planetary Institute

Science.gov (United States)

Shaner, Andrew; Shupla, Christine; Smith Hackler, Amanda; Buxner, Sanlyn; Wenger, Matthew; Joseph, Emily C. S.

2016-10-01

The Lunar and Planetary Institute's (LPI) public engagement programs target audiences of all ages and backgrounds; in 2016 LPI has expanded its programs to reach wider, more diverse audiences. The status, resources, and findings of these programs, including evaluation results, will be discussed in this poster. LPI's Cosmic Explorations Speaker Series (CESS) is an annual public speaker series to engage the public in space science and exploration. Each thematic series includes four to five presentations held between September and May. Past series' titles have included "Science" on the Silver Screen, The Universe is Out to Get Us and What We Can (or Can't) Do About It, and A User's Guide to the Universe: You Live Here. Here's What You Need to Know. While the presentations are available online after the event, they are now being livestreamed to be accessible to a broader national, and international, audience. Sky Fest events, held four to five times a year, have science content themes and include several activities for children and their parents, night sky viewing through telescopes, and scientist presentations. Themes include both planetary and astronomy topics as well as planetary exploration topics (e.g., celebrating the launch or landing of a spacecraft). Elements of the Sky Fest program are being conducted in public libraries serving audiences underrepresented in STEM near LPI. These programs take place as part of existing hour-long programs in the library. During this hour, young people, typically 6-12 years old, move through three stations where they participate in hands-on activities. Like Sky Fest, these programs are thematic, centered on one over-arching topic such as the Moon or Mars. Beginning in Fall 2016, LPI will present programs at a revitalized park in downtown Houston. Facilities at this park will enable LPI to bring both the Sky Fest and CESS programs into the heart of Houston, which is one of the most diverse cities in the US and the world.

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.

Plastic deformation of FeSi at high pressures: implications for planetary cores

Science.gov (United States)

Kupenko, Ilya; Merkel, Sébastien; Achorner, Melissa; Plückthun, Christian; Liermann, Hanns-Peter; Sanchez-Valle, Carmen

2017-04-01

The cores of terrestrial planets is mostly comprised of a Fe-Ni alloy, but it should additionally contain some light element(s) in order to explain the observed core density. Silicon has long been considered as a likely candidate because of geochemical and cosmochemical arguments: the Mg/Si and Fe/Si ratios of the Earth does not match those of the chondrites. Since silicon preferentially partition into iron-nickel metal, having 'missing' silicon in the core would solve this problem. Moreover, the evidence of present (e.g. Mercury) or ancient (e.g. Mars) magnetic fields on the terrestrial planets is a good indicator of (at least partially) liquid cores. The estimated temperature profiles of these planets, however, lay below iron melting curve. The addition of light elements in their metal cores could allow reducing their core-alloy melting temperature and, hence, the generation of a magnetic field. Although the effect of light elements on the stability and elasticity of Fe-Ni alloys has been widely investigated, their effect on the plasticity of core materials remains largely unknown. Yet, this information is crucial for understanding how planetary cores deform. Here we investigate the plastic deformation of ɛ-FeSi up to 50 GPa at room temperature employing a technique of radial x-ray diffraction in diamond anvil cells. Stoichiometric FeSi endmember is a good first-order approximation of the Fe-FeSi system and a good starting material to develop new experimental perspectives. In this work, we focused on the low-pressure polymorph of FeSi that would be the stable phase in the cores of small terrestrial planets. We will present the analysis of measured data and discuss their potential application to constrain plastic deformation in planetary cores.

SmallSat Missions Traveling to Planetary Targets from Near-Earth-Space: Applications for Space Physics

Science.gov (United States)

Espley, J. R.; Folta, D.

2017-12-01

Recent advances in propulsion technology and interplanetary navigation theoretically allow very small spacecraft to travel directly to planetary destinations from near-Earth-space. Because there are currently many launches with excess mass capability (NASA, military, and even commercial), we anticipate a dramatic increase in the number of opportunities for missions to planetary targets. Spacecraft as small as 12U CubeSats can use solar electric propulsion to travel from Earth-orbit to Mars-orbit in approximately 2-3 years. Space physics missions are particularly well suited for such mission architectures since state-of-the-art instrumentation to answer fundamental science questions can be accommodated in relatively small payload packages. For example, multi-point measurements of the martian magnetosphere, ionosphere, and crustal magnetic fields would yield important new science results regarding atmospheric escape and the geophysical history of the martian surface. These measurements could be accomplished by a pair of 12U CubeSats with world-class instruments that require only modest mass, power, and telemetry resources (e.g. Goddard's mini-fluxgate vector magnetometer).

THE HYADES CLUSTER: IDENTIFICATION OF A PLANETARY SYSTEM AND ESCAPING WHITE DWARFS

International Nuclear Information System (INIS)

Zuckerman, B.; Xu, S.; Klein, B.; Jura, M.

2013-01-01

Recently, some hot DA-type white dwarfs have been proposed to plausibly be escaping members of the Hyades. We used hydrogen Balmer lines to measure the radial velocities of seven such stars and confirm that three, and perhaps two others, are/were indeed cluster members and one is not. The other candidate Hyad is strongly magnetic and its membership status remains uncertain. The photospheres of at least one quarter of field white dwarf stars are ''polluted'' by elements heavier than helium that have been accreted. These stars are orbited by extended planetary systems that contain both debris belts and major planets. We surveyed the seven classical single Hyades white dwarfs and the newly identified (escaping) Hyades white dwarfs and found calcium in the photosphere of LP 475-242 of type DBA (now DBAZ), thus implying the presence of an orbiting planetary system. The spectrum of white dwarf GD 31, which may be, but probably is not, an escaping member of the Hyades, displays calcium absorption lines; these originate either from the interstellar medium or, less likely, from a gaseous circumstellar disk. If GD 31 was once a Hyades member, then it would be the first identified white dwarf Hyad with a cooling age >340 Myr.

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

An enhanced Planetary Radar Operating Centre (PROC)

Science.gov (United States)

Catallo, C.

2010-12-01

Planetary exploration by means of radar systems, mainly using GPRs is an important role of Italy and numerous scientific international space programs are carried out jointly with ESA and NASA by Italian Space Agency, the scientific community and the industry. Three experiments under Italian leadership ( designed and manufactured by the Italian industry) provided by ASI within a NASA/ESA/ASI joint venture framework are successfully operating: MARSIS on-board MEX, SHARAD on-board MRO and CASSINI Radar on-board Cassini spacecraft: the missions have been further extended . Three dedicated operational centers, namely SHOC, (Sharad Operating Centre), MOC (Marsis Operating Center) and CASSINI PAD are operating from the missions beginning to support all the scientific communities, institutional customers and experiment teams operation Each center is dedicated to a single instrument management and control, data processing and distribution and even if they had been conceived to operate autonomously and independently one from each other, synergies and overlaps have been envisaged leading to the suggestion of a unified center, the Planetary Radar Processing Center (PROC). In order to harmonize operations either from logistics point of view and from HW/SW capabilities point of view PROC is designed and developed for offering improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation. PROC is, therefore, conceived as the Italian support facility to the scientific community for on-going and future Italian planetary exploration programs, such as Europa-Jupiter System Mission (EJSM) The paper describes how the new PROC is designed and developed, to allow SHOC, MOC and CASSINI PAD to operate as before, and to offer improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation aiding scientists to increase their knowledge in the field of surface

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.

PREFACE: Selected invited contributions from the International Conference on Magnetism (Karlsruhe, Germany, 26-31 July 2009) Selected invited contributions from the International Conference on Magnetism (Karlsruhe, Germany, 26-31 July 2009)

Science.gov (United States)

Goll, Gernot; Löhneysen, Hilbert v.; Loidl, Alois; Pruschke, Thomas; Richter, Manuel; Schultz, Ludwig; Sürgers, Christoph; Wosnitza, Jochen

2010-04-01

The International Conference on Magnetism 2009 (ICM 2009) was held in Karlsruhe, Germany, from 26 to 31 July 2009. Previous conferences in this series were organized in Edinburgh, UK (1991), Warsaw, Poland (1994), Cairns, Australia (1997), Recife, Brazil (2000), Rome, Italy (2003), and Kyoto, Japan (2006). As with previous ICM conferences, the annual Conference on Strongly Correlated Electron Systems (SCES) was integrated into ICM 2009. The topics presented at ICM 2009 were strongly correlated electron systems, quantum and classical spin systems, magnetic structures and interactions, magnetization dynamics and micromagnetics, spin-dependent transport, spin electronics, magnetic thin films, particles and nanostructures, soft and hard magnetic materials and their applications, novel materials and device applications, magnetic recording and memories, measuring techniques and instrumentation, as well as interdisciplinary topics. We are grateful to the International Advisory Committee for their help in coordinating an attractive program encompassing practically all aspects of magnetism, both experimentally and theoretically. The Program Committee comprised A Loidl, Germany (Chair), M A Continentino, Brazil, D E Dahlberg, USA, D Givord, France, G Güntherodt, Germany, H Mikeska, Germany, D Kaczorowski, Poland, Ching-Ray Chang, South Korea, I Mertig, Germany, D Vollhardt, Germany, and E F Wassermann, Germany. E F Wassermann was also head of the National Organizing Committee. His help is gratefully acknowledged. The scientific program started on Monday 27 July 2009 with opening addresses by the Conference Chairman, the Deputy Mayor of Karlsruhe, Ms M Mergen and the Chairman of the Executive Board of Forschungszentrum Karlsruhe, E Umbach. ICM 2009 was attended by the Nobel Laureates P W Anderson, A Fert and P Grünberg who gave plenary talks. A special highlight was the presentation of the Magnetism Award and Néel Medal to S S P Parkin who also presented his newest results

A New Model of Jupiter's Magnetic Field from Juno's First Nine Orbits

DEFF Research Database (Denmark)

Connerney, J. E. P.; Kotsiaros, S.; Oliversen, R. J.

2018-01-01

A spherical harmonic model of the magnetic field of Jupiter is obtained from vector magnetic field observations acquired by the Juno spacecraft during its first nine polar orbits about the planet. Observations acquired during eight of these orbits provide the first truly global coverage of Jupiter...... currents. Partial solution of the underdetermined inverse problem using generalized inverse techniques yields a model (“Juno Reference Model through Perijove 9”) of the planetary magnetic field with spherical harmonic coefficients well determined through degree and order 10, providing the first detailed...

Planetary gyre, time-dependent eddies, torsional waves, and equatorial jets at the Earth's core surface

DEFF Research Database (Denmark)

Gillet, N.; Jault, D.; Finlay, Chris

2015-01-01

between the magnetic field and subdecadal nonzonal motions within the fluid outer core. Both the zonal and the more energetic nonzonal interannual motions were particularly intense close to the equator (below 10∘ latitude) between 1995 and 2010. We revise down the amplitude of the decade fluctuations......We report a calculation of time-dependent quasi-geostrophic core flows for 1940–2010. Inverting recursively for an ensemble of solutions, we evaluate the main source of uncertainties, namely, the model errors arising from interactions between unresolved core surface motions and magnetic fields....... Temporal correlations of these uncertainties are accounted for. The covariance matrix for the flow coefficients is also obtained recursively from the dispersion of an ensemble of solutions. Maps of the flow at the core surface show, upon a planetary-scale gyre, time-dependent large-scale eddies...

Gyre-driven decay of the Earth’s magnetic dipole

DEFF Research Database (Denmark)

Finlay, Christopher C.; Aubert, Julien; Gillet, Nicolas

2016-01-01

Direct observations indicate that the magnitude of the Earth’s magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre...

Vibration characteristics of two-stage planetary transmission system with thin-walled ring gear on elastic supports

Science.gov (United States)

Li, JianYing; Hu, QingChun; Zong, ChangFu; Zhu, TianJun; Zhang, ZeXing

2018-03-01

A dual-clutch and dual-speed planetary gears mechanism of a hybrid car coupled-system is taken as research subject, in which the ring gear of planet set II is a thin-walled structure and the clutch friction plates of planet set II are used as its elastic supports. Based on the lumped parameter-rigid elastic coupled dynamic model of two-stage planetary transmission system with thin-walled ring gear on elastic supports, the motion differential equations are established and the dynamic responses are solved by the Runge-Kutta method considering each stage internal and external time-varying mesh stiffness. The vibration displacements of each stage ring gear have been affected differently in time-domain, the translational vibration displacement of the ring gear of planet set I are obviously more than the torsional vibration displacement, but it is opposite for the ring gear of planet set II; The translational and torsional vibration responses of each stage ring gear arrive the peak in low-frequency. The analysis results of this paper can enrich the theoretical research of multistage planetary transmission and provide guidance for dynamic design.

Observation of changing of the internal conversion coefficient under Moessbauer effect at magnetic transition in Rh-Fe system

International Nuclear Information System (INIS)

Ruskov, T.

1998-01-01

The magnetic disorder-order transition in the Rh-Fe alloy is studied by conversion electron Moessbauer spectroscopy. The drastic increase of the area under the Moessbauer spectrum at the transition from the paramagnetic to the magnetic state could be explained by diminishing the internal conversion coefficient. Thus our experimental results directly confirm the theory of the collective effect in the system of radiating developed by Yukalov

Nonlinear Wave-Particle Interaction: Implications for Newborn Planetary and Backstreaming Proton Velocity Distribution Functions

Science.gov (United States)

Romanelli, N.; Mazelle, C.; Meziane, K.

2018-02-01

Seen from the solar wind (SW) reference frame, the presence of newborn planetary protons upstream from the Martian and Venusian bow shocks and SW protons reflected from each of them constitutes two sources of nonthermal proton populations. In both cases, the resulting proton velocity distribution function is highly unstable and capable of giving rise to ultralow frequency quasi-monochromatic electromagnetic plasma waves. When these instabilities take place, the resulting nonlinear waves are convected by the SW and interact with nonthermal protons located downstream from the wave generation region (upstream from the bow shock), playing a predominant role in their dynamics. To improve our understanding of these phenomena, we study the interaction between a charged particle and a large-amplitude monochromatic circularly polarized electromagnetic wave propagating parallel to a background magnetic field, from first principles. We determine the number of fix points in velocity space, their stability, and their dependence on different wave-particle parameters. Particularly, we determine the temporal evolution of a charged particle in the pitch angle-gyrophase velocity plane under nominal conditions expected for backstreaming protons in planetary foreshocks and for newborn planetary protons in the upstream regions of Venus and Mars. In addition, the inclusion of wave ellipticity effects provides an explanation for pitch angle distributions of suprathermal protons observed at the Earth's foreshock, reported in previous studies. These analyses constitute a mean to evaluate if nonthermal proton velocity distribution functions observed at these plasma environments present signatures that can be understood in terms of nonlinear wave-particle processes.

Turbulence, transport and confinement: from tokamaks to star magnetism

International Nuclear Information System (INIS)

Strugarek, Antoine

2012-01-01

This thesis is part of the general study of self-organization in hot and magnetized plasmas. We focus our work on two specific objects: stars and tokamaks. We use first principle numerical simulations to study turbulence, transport and confinement in these plasmas. The first part of this thesis introduces the main characteristics of stellar and tokamak plasmas. The reasons for studying them together are properly detailed. The second part is focused on stellar aspects. We study the interactions between the 3D turbulent motions in the solar convection zone with an internal magnetic field in the tachocline (the transition region between the instable and stable zones in the Sun). The tachocline is a very thin layer (less than five percent of the solar radius) that acts as a transport barrier of angular momentum. We show that such an internal magnetic field is not likely to explain the observed thickness of the tachocline and we give some insights on how to find alternative mechanisms to constrain it. We also explore the effect of the environment of star on its structure. We develop a methodology to study the influence of stellar wind and of the magnetic coupling of a star with its orbiting planets. We use the same methodology to analyse the magnetic interaction between a stellar wind and a planetary magnetosphere that acts as a transport barrier of matter. Then, the third part is dedicated to fusion oriented research. We present a numerical investigation on the experimental mechanisms that lead to the development of transport barriers in the plasma. These barriers are particularly important for the design of high performance fusion devices. The creation of transport barriers is obtained in turbulent first principle simulations for the very first time. The collaboration between the two scientific teams lead to the results presented in the fourth part of this thesis. An original spectral method is developed to analyse the saturation of stellar convective dynamos and of

International legal framework for geoengineering: Managing the risks of an emerging technology

NARCIS (Netherlands)

Du, Haomiao

2016-01-01

The present book “International Legal Framework for Geoengineering – Managing the Risks of an Emerging Technology” is about international law and an emerging technology called geoengineering, which refers to the large-scale manipulation of the planetary environment for counteracting anthropogenic

The 8th International Conference on Highly Frustrated Magnetism (HFM 2016)

Science.gov (United States)

Gardner, J. S.; Kao, Y. J.

2017-04-01

The 8th International Conference on Highly Frustrated Magnetism 2016 (HFM 2016) took place between the 7th and 11th of September 2016 at the GIS Convention Center at National Taiwan University, Taipei, Taiwan. Over 260 participants from all over the world, attended the meeting making it the largest HFM to-date and revealing the impressive growth in the community since the original meeting in Waterloo, Canada where 80 participants attended. Preceding the meeting a school was held at the National Synchrotron Radiation Research Center to help those new to the field understand the material they were likely to see at HFM2016. Our thanks to the international speakers who attended this school John Chalker, Michel Kenzelmann, Philippe Mendels, Luigi Paolasini, Kirrily Rule, Yixi Su, Isao Watanabe and those from Taiwan W. T. Chen, Y-J, Kao, L. J. Chang and C. S. Ku, for their enlightening presentations. The HFM 2016 conference consisted of five plenary talks by H Takagi, B D Gaulin, L Balents, Y Tokura and S T Bramwell, 20 invited and 40 contributed presentations, and about 160 poster presentations from all aspects of theoretical and experimental frustrated magnetism. During the conference period, many stimulating discussions were held both inside and outside the conference room. Excursions to Taipei 101 and the National Palace Museum, as well as several organized dinners and receptions allowed the participants to initiate collaborations and discuss the hottest issues. The subjects covered in the conference included: · Quantum frustrated magnetism and spin liquids · Novel ordering of geometrically frustrated magnets · Frustration effect on the coupling to lattice, orbital and charge degrees of freedom · Exotic phenomena induced by macroscopic degeneracy · Field effect on frustrated magnetism etc. These proceeding represent a very small, but valuable contribution to the community. I hope you enjoy reading them. In view of the rapid growth of the field, it has been

The Planetary Collegium: Master Plan for a Distributed Mixed Reality Campus

Directory of Open Access Journals (Sweden)

Peter Anders

2012-10-01

Full Text Available This paper describes the design for a Mixed Reality campusfor the Planetary Collegium. The Collegium is an international research network centered at Plymouth, U.K. Its plans call for seven sub-centers, or nodes, to be builtin different parts of the world. These nodes would be linked by shared virtual spaces and digital networks. The paper describes how the Collegium’s seeming contradictions (distributed/unified, simulated/physical, local/remote can be reconciled. The resulting project is a mixed reality that transcends scales from global to local and, ultimately, to the constituent buildings and their digital spaces.

Discontinuity model for internal transport barrier formation in reversed magnetic shear plasmas

International Nuclear Information System (INIS)

Kishimoto, Y.; Kim, J-Y.; Horton, W.; Tajima, T.; LeBrun, M.J.

2001-01-01

To aid in understanding the internal transport barrier (ITB) being formed in reversed magnetic shear experiments, in addition to the well known shear flow effect, we point out an important nonlocal effect and/or finite size effect which comes from the complex behavior of the nonlocal mode over a finite radial region around the minimum q(safety factor)-surface. The nonlocal mode changes its structure depending on the sign of the magnetic shear and due to this fact, the nonlocal modes are weakly excited across the q min -surface. This leads to a discontinuity or gap which disconnects the phase relation in the global wave structure across the q min -surface. Once such a discontinuity (or gap) is formed, transport suppression occurs and therefore a transport barrier can be expected near the q min -surface. We confirm the existence of this discontinuity using a toroidal particle simulation. (author)

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.

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.;

Physics of magnetic flux ropes. Geophysical Monograph, No. 58

International Nuclear Information System (INIS)

Russell, C.T.; Priest, E.R.; Lee, L.C.

1990-01-01

The present work encompasses papers on the structure, waves, and instabilities of magnetic flux ropes (MFRs), photospheric flux tubes (PFTs), the structure and heating of coronal loops, solar prominences, coronal mass ejections and magnetic clouds, flux ropes in planetary ionospheres, the magnetopause, magnetospheric field-aligned currents and flux tubes, and the magnetotail. Attention is given to the equilibrium of MFRs, resistive instability, magnetic reconnection and turbulence in current sheets, dynamical effects and energy transport in intense flux tubes, waves in solar PFTs, twisted flux ropes in the solar corona, an electrodynamical model of solar flares, filament cooling and condensation in a sheared magnetic field, the magnetopause, the generation of twisted MFRs during magnetic reconnection, ionospheric flux ropes above the South Pole, substorms and MFR structures, evidence for flux ropes in the earth magnetotail, and MFRs in 3D MHD simulations

Implementing planetary protection measures on the Mars Science Laboratory.

Science.gov (United States)

Benardini, James N; La Duc, Myron T; Beaudet, Robert A; Koukol, Robert

2014-01-01

The Mars Science Laboratory (MSL), comprising a cruise stage; an aeroshell; an entry, descent, and landing system; and the radioisotope thermoelectric generator-powered Curiosity rover, made history with its unprecedented sky crane landing on Mars on August 6, 2012. The mission's primary science objective has been to explore the area surrounding Gale Crater and assess its habitability for past life. Because microbial contamination could profoundly impact the integrity of the mission and compliance with international treaty was required, planetary protection measures were implemented on MSL hardware to verify that bioburden levels complied with NASA regulations. By applying the proper antimicrobial countermeasures throughout all phases of assembly, the total bacterial endospore burden of MSL at the time of launch was kept to 2.78×10⁵ spores, well within the required specification of less than 5.0×10⁵ spores. The total spore burden of the exposed surfaces of the landed MSL hardware was 5.64×10⁴, well below the allowed limit of 3.0×10⁵ spores. At the time of launch, the MSL spacecraft was burdened with an average of 22 spores/m², which included both planned landed and planned impacted hardware. Here, we report the results of a campaign to implement and verify planetary protection measures on the MSL flight system.

Dynamic Response of a Planetary Gear System Using a Finite Element/Contact Mechanics Model

Science.gov (United States)

Parker, Robert G.; Agashe, Vinayak; Vijayakar, Sandeep M.

2000-01-01

The dynamic response of a helicopter planetary gear system is examined over a wide range of operating speeds and torques. The analysis tool is a unique, semianalytical finite element formulation that admits precise representation of the tooth geometry and contact forces that are crucial in gear dynamics. Importantly, no a priori specification of static transmission error excitation or mesh frequency variation is required; the dynamic contact forces are evaluated internally at each time step. The calculated response shows classical resonances when a harmonic of mesh frequency coincides with a natural frequency. However, peculiar behavior occurs where resonances expected to be excited at a given speed are absent. This absence of particular modes is explained by analytical relationships that depend on the planetary configuration and mesh frequency harmonic. The torque sensitivity of the dynamic response is examined and compared to static analyses. Rotation mode response is shown to be more sensitive to input torque than translational mode response.

Planetary Structures And Simulations Of Large-scale Impacts On Mars

Science.gov (United States)

Swift, Damian; El-Dasher, B.

2009-09-01

The impact of large meteroids is a possible cause for isolated orogeny on bodies devoid of tectonic activity. On Mars, there is a significant, but not perfect, correlation between large, isolated volcanoes and antipodal impact craters. On Mercury and the Moon, brecciated terrain and other unusual surface features can be found at the antipodes of large impact sites. On Earth, there is a moderate correlation between long-lived mantle hotspots at opposite sides of the planet, with meteoroid impact suggested as a possible cause. If induced by impacts, the mechanisms of orogeny and volcanism thus appear to vary between these bodies, presumably because of differences in internal structure. Continuum mechanics (hydrocode) simulations have been used to investigate the response of planetary bodies to impacts, requiring assumptions about the structure of the body: its composition and temperature profile, and the constitutive properties (equation of state, strength, viscosity) of the components. We are able to predict theoretically and test experimentally the constitutive properties of matter under planetary conditions, with reasonable accuracy. To provide a reference series of simulations, we have constructed self-consistent planetary structures using simplified compositions (Fe core and basalt-like mantle), which turn out to agree surprisingly well with the moments of inertia. We have performed simulations of large-scale impacts, studying the transmission of energy to the antipodes. For Mars, significant antipodal heating to depths of a few tens of kilometers was predicted from compression waves transmitted through the mantle. Such heating is a mechanism for volcanism on Mars, possibly in conjunction with crustal cracking induced by surface waves. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Partnering to Enhance Planetary Science Education and Public Outreach Program

Science.gov (United States)

Dalton, Heather; Shipp, Stephanie; Shupla, Christine; Shaner, Andrew; LaConte, Keliann

2015-11-01

The Lunar and Planetary Institute (LPI) in Houston, Texas utilizes many partners to support its multi-faceted Education and Public Outreach (E/PO) program. The poster will share what we have learned about successful partnerships. One portion of the program is focused on providing training and NASA content and resources to K-12 educators. Teacher workshops are performed in several locations per year, including LPI and the Harris County Department of Education, as well as across the country in cooperation with other programs and NASA Planetary Science missions.To serve the public, LPI holds several public events per year called Sky Fest, featuring activities for children, telescopes for night sky viewing, and a short scientist lecture. For Sky Fest, LPI partners with the NASA Johnson Space Center Astronomical Society; they provide the telescopes and interact with members of the public as they are viewing celestial objects. International Observe the Moon Night (InOMN) is held annually and involves the same aspects as Sky Fest, but also includes partners from Johnson Space Center’s Astromaterials Research and Exploration Science group, who provide Apollo samples for the event.Another audience that LPI E/PO serves is the NASA Planetary Science E/PO community. Partnering efforts for the E/PO community include providing subject matter experts for professional development workshops and webinars, connections to groups that work with diverse and underserved audiences, and avenues to collaborate with groups such as the National Park Service and the Afterschool Alliance.Additional information about LPI’s E/PO programs can be found at http://www.lpi.usra.edu/education. View a list of LPI E/PO’s partners here: http://www.lpi.usra.edu/education/partners/.

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

MAGNETIC SHIELDING OF EXOMOONS BEYOND THE CIRCUMPLANETARY HABITABLE EDGE

International Nuclear Information System (INIS)

Heller, René; Zuluaga, Jorge I.

2013-01-01

With most planets and planetary candidates detected in the stellar habitable zone (HZ) being super-Earths and gas giants rather than Earth-like planets, we naturally wonder if their moons could be habitable. The first detection of such an exomoon has now become feasible, and due to observational biases it will be at least twice as massive as Mars. However, formation models predict that moons can hardly be as massive as Earth. Hence, a giant planet's magnetosphere could be the only possibility for such a moon to be shielded from cosmic and stellar high-energy radiation. Yet, the planetary radiation belt could also have detrimental effects on exomoon habitability. Here we synthesize models for the evolution of the magnetic environment of giant planets with thresholds from the runaway greenhouse (RG) effect to assess the habitability of exomoons. For modest eccentricities, we find that satellites around Neptune-sized planets in the center of the HZ around K dwarf stars will either be in an RG state and not be habitable, or they will be in wide orbits where they will not be affected by the planetary magnetosphere. Saturn-like planets have stronger fields, and Jupiter-like planets could coat close-in habitable moons soon after formation. Moons at distances between about 5 and 20 planetary radii from a giant planet can be habitable from an illumination and tidal heating point of view, but still the planetary magnetosphere would critically influence their habitability

MAGNETIC SHIELDING OF EXOMOONS BEYOND THE CIRCUMPLANETARY HABITABLE EDGE

Energy Technology Data Exchange (ETDEWEB)

Heller, René [McMaster University, Department of Physics and Astronomy, Hamilton, ON L8S 4M1 (Canada); Zuluaga, Jorge I., E-mail: rheller@physics.mcmaster.ca, E-mail: jzuluaga@fisica.udea.edu.co [FACom - Instituto de Física - FCEN, Universidad de Antioquia, Calle 70 No. 52-21, Medellín (Colombia)

2013-10-20

With most planets and planetary candidates detected in the stellar habitable zone (HZ) being super-Earths and gas giants rather than Earth-like planets, we naturally wonder if their moons could be habitable. The first detection of such an exomoon has now become feasible, and due to observational biases it will be at least twice as massive as Mars. However, formation models predict that moons can hardly be as massive as Earth. Hence, a giant planet's magnetosphere could be the only possibility for such a moon to be shielded from cosmic and stellar high-energy radiation. Yet, the planetary radiation belt could also have detrimental effects on exomoon habitability. Here we synthesize models for the evolution of the magnetic environment of giant planets with thresholds from the runaway greenhouse (RG) effect to assess the habitability of exomoons. For modest eccentricities, we find that satellites around Neptune-sized planets in the center of the HZ around K dwarf stars will either be in an RG state and not be habitable, or they will be in wide orbits where they will not be affected by the planetary magnetosphere. Saturn-like planets have stronger fields, and Jupiter-like planets could coat close-in habitable moons soon after formation. Moons at distances between about 5 and 20 planetary radii from a giant planet can be habitable from an illumination and tidal heating point of view, but still the planetary magnetosphere would critically influence their habitability.

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.

Magnet systems for the International Thermonuclear Experimental Reactor

International Nuclear Information System (INIS)

Henning, C.D.; Miller, J.R.

1988-01-01

The definition phase for the International Thermonuclear Experimental Reactor (ITER) has been nearly completed, thus beginning a three-year design effort by teams from the European Community (EC), Japan, US, and USSR. Preliminary parameters for the superconducting magnet system have been established to guide more detailed design work. Radiation tolerance of the superconductors and insulators has been important because it sets requirements for the neutron-shield dimension and sensitively influences reactor size. Major levels of mechanical stress appear in the structural cases of the inboard legs of the toroidal-field (TF) coils. The winding packs of the TF coils include significant fractions of steel that provide support against in-plane separating loads, but they offer little support against out-of-plane loads unless shear-bonding of the conductors can be maintained. Heat removal from nuclear and ac loads has not limited the fundamental design, but it has nonnegligible economic consequences. 3 refs., 3 figs., 5 tabs

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.

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...

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.

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.

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

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.

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.

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.

Magnetic fields of Jupiter and Saturn

International Nuclear Information System (INIS)

Ness, N.F.

1981-01-01

The magnetic fields of Jupiter and Saturn and the characteristics of their magnetospheres, formed by interaction with the solar wind, are discussed. The origins of both magnetic fields are associated with a dynamo process deep in the planetary interior. The Jovian magnetosphere is analogous to that of a pulsar magnetosphere: a massive central body with a rapid rotation and an associated intense magnetic field. Its most distinctive feature is its magnetodisk of concentrated plasma and particle flux, and reduced magnetic field intensity. The magnetopause near the subsolar point has been observed at radial distances ranging over 50 to 100 Jovian radii, implying a relatively compressible obstacle to solar wind flow. The composition of an embedded current sheet within the magnetic tail is believed to be influenced by volcanic eruptions and emissions from Io. Spectral troughs of the Jovian radiation belts have been interpreted as possible ring particles. The Saturnian magnetosphere appears to be more like the earth in its topology. It is mainly characterized by a dipole axis parallel to the rotational axis of the planet and a magnetic field intensity much less than expected

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

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

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...

Magnetic fields at Neptune

International Nuclear Information System (INIS)

Ness, N.F.; Acuna, M.H.; Burlaga, L.F.; Connerney, J.E.P.; Lepping, R.P.; Neubauer, F.M.

1989-01-01

The National Aeronautics and Space Administration Goddard Space Flight Center-University of Delaware Bartol Research Institute magnetic field experiment on the Voyager 2 spacecraft discovered a strong and complex intrinsic magnetic field of Neptune and an associated magnetosphere and magnetic tail. A maximum magnetic field of nearly 10,000 nanoteslas (1 nanotesla = 10 -5 gauss) was observed near closest approach, at a distance of 1.18 R N . The planetary magnetic field between 4 and 15 R N can be well represented by an offset tilted magnetic dipole (OTD), displaced from the center of Neptune by the surprisingly large amount of 0.55 R N and inclined by 47 degrees with respect to the rotation axis. Within 4 R N , the magnetic field representation must include localized sources or higher order magnetic multipoles, or both, which are not yet well determined. As the spacecraft exited the magnetosphere, the magnetic tail appeared to be monopolar, and no crossings of an imbedded magnetic field reversal or plasma neutral sheet were observed. The auroral zones are most likely located far from the rotation poles and may have a complicated geometry. The rings and all the known moons of Neptune are imbedded deep inside the magnetosphere, except for Nereid, which is outside when sunward of the planet. The radiation belts will have a complex structure owing to the absorption of energetic particles by the moons and rings of Neptune and losses associated with the significant changes in the diurnally varying magnetosphere configuration. In an astrophysical context, the magnetic field of Neptune, like that of Uranus, may be described as that of an oblique rotator

Internal magnetic probe data from ZT-40

International Nuclear Information System (INIS)

Burkhardt, L.C.; Phillips, J.A.

1981-05-01

Measurements of magnetic field distribution as a function of time and radius were made in ZT-40 with its ceramic vacuum vessel. Data were obtained with a 10-station, 20-coil magnetic probe, measuring the B/sub p/ and B/sub epsilon/ orthogonal field components in deuterium plasma discharges. Sheath formation and diffusion, magnetic axis location and motion, the effect of the probe on the plasma, and the consistency of flux measurements with external probes are examined

Correlation between internal derangement and osteoarthrosis in the temporomandibular joint using magnetic resonance imaging

International Nuclear Information System (INIS)

Song, Haeng Un; Choi, Sun Young; Koh, Kwang Joon

2002-01-01

To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

Correlation between internal derangement and osteoarthrosis in the temporomandibular joint using magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Song, Haeng Un; Choi, Sun Young; Koh, Kwang Joon [School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of)

2002-12-15

To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

A bearingless coaxial magnetic gearbox

Directory of Open Access Journals (Sweden)

A.S. Abdel-Khalik

2014-09-01

Full Text Available Recently, magnetic gearboxes (MGBs are serious contenders to their conventional mechanical counterparts in terms of reduced maintenance requirements, improved reliability, tolerance to mechanical inaccuracies, and inherent overload protection. MGBs are preferably employed in high speed applications and compact harsh environments subjected to severe shock and vibration. A high gear ratio MGB is also a suitable candidate for single stage high-speed transmission applications such as helicopter power transmissions. In this paper, the conventional planetary magnetic gearbox is equipped with a three-phase winding to provide additional magnetic levitation capabilities besides torque transmission, thus creating a bearingless MGB configuration. This was achieved by adding a three-phase winding in the space between the ferromagnetic pieces. The current in this additional winding is controlled to provide decoupled axial forces irrespective of the transmitted mechanical power. This feature is important to reduce the mechanical losses especially for high-speed rotors and can be a viable method for vibration suppression.

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.)

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.

Long-lived magnetism from solidification-driven convection on the pallasite parent body

DEFF Research Database (Denmark)

Bryson, James F.J.; Nichols, Claire I. O.; Herrero-Albillos, Julia

2015-01-01

of long-lived magnetic activity on the pallasite parent body, capturing the decay and eventual shutdown of the magnetic field as core solidification completed.We demonstrate that magnetic activity driven by progressive solidification of an inner core is consistent with our measuredmagnetic field......Palaeomagnetic measurements of meteorites suggest that, shortly after the birth of the Solar System, themolten metallic cores ofmany small planetary bodies convected vigorously and were capable of generating magnetic fields. Convection on these bodies is currently thought to have been thermally...... characteristics and cooling rates. Solidification-driven convectionwas probably commonamong small body cores, and, in contrast to thermally driven convection, will have led to a relatively late (hundreds of millions of years after accretion), long-lasting, intense and widespread epoch of magnetic activity among...

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

Recycling of SmCo5 magnets by HD process

Science.gov (United States)

Eldosouky, Anas; Škulj, Irena

2018-05-01

Hydrogen decrepitation process has been applied for the first time for the direct recycling of SmCo5 magnets. Industrially produced sintered SmCo5 magnets were decrepitated by hydrogen gas at a pressure of 1 bar to 9.5 bar at room temperature in a planetary rotating jar. After decrepitation, the starting sintered magnets were reduced to a powder with a particle size of less than 200 μm. The produced powder was used for the preparation of recycled SmCo5 magnets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction studies and magnetic measurements were used to follow the decrepitation and the sintering processes. The measured remanence and maximum energy product of the recycled magnet are 0.94 T and 171.1 kJ/m3, respectively, in comparison with 0.91 T and 156.8 kJ/m3, respectively for the original magnet before recycling. It was also observed that, there is refinement in the microstructure after recycling in comparison to the original magnet.

Design considerations for ITER [International Thermonuclear Experimental Reactor] magnet systems: Revision 1

International Nuclear Information System (INIS)

Henning, C.D.; Miller, J.R.

1988-01-01

The International Thermonuclear Experimental Reactor (ITER) is now completing a definition phase as a beginning of a three-year design effort. Preliminary parameters for the superconducting magnet system have been established to guide further and more detailed design work. Radiation tolerance of the superconductors and insulators has been of prime importance, since it sets requirements for the neutron-shield dimension and sensitively influences reactor size. The major levels of mechanical stress in the structure appear in the cases of the inboard legs of the toroidal-field (TF) coils. The cases of the poloidal-field (PF) coils must be made thin or segmented to minimize eddy current heating during inductive plasma operation. As a result, the winding packs of both the TF and PF coils includes significant fractions of steel. The TF winding pack provides support against in-plane separating loads but offers little support against out-of-plane loads, unless shear-bonding of the conductors can be maintained. The removal of heat due to nuclear and ac loads has not been a fundamental limit to design, but certainly has non-negligible economic consequences. We present here preliminary ITER magnet systems design parameters taken from trade studies, designs, and analyses performed by the Home Teams of the four ITER participants, by the ITER Magnet Design Unit in Garching, and by other participants at workshops organized by the Magnet Design Unit. The work presented here reflects the efforts of many, but the responsibility for the opinions expressed is the authors'. 4 refs., 3 figs., 4 tabs

Comparing superconducting and permanent magnets for magnetic refrigeration

Directory of Open Access Journals (Sweden)

R. Bjørk

2016-05-01

Full Text Available We compare the cost of a high temperature superconducting (SC tape-based solenoid with a permanent magnet (PM Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 $/m2 and a price of the permanent magnet of 100 $/kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications.

Effects of internal structure on equilibrium of field-reversed configuration plasma sustained by rotating magnetic field

International Nuclear Information System (INIS)

Yambe, Kiyoyuki; Inomoto, Michiaki; Okada, Shigefumi; Kobayashi, Yuka; Asai, Tomohiko

2008-01-01

The effects of an internal structure on the equilibrium of a field-reversed configuration (FRC) plasma sustained by rotating magnetic field is investigated by using detailed electrostatic probe measurements in the FRC Injection Experiment apparatus [S. Okada, et al., Nucl. Fusion. 45, 1094 (2005)]. An internal structure installed axially on the geometrical axis, which simulates Ohmic transformer or external toroidal field coils on the FRC device, brings about substantial changes in plasma density profile. The internal structure generates steep density-gradients not only on the inner side but on the outer side of the torus. The radial electric field is observed to sustain the ion thermal pressure-gradient in the FRC without the internal structure; however, the radial electric field is not sufficient to sustain the increased ion thermal pressure-gradient in the FRC with the internal structure. Spontaneously driven azimuthal ion flow will be accountable for the imbalance of the radial pressure which is modified by the internal structure.

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.

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.

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.

Magnetic field of Mercury and models of thermal evolution

International Nuclear Information System (INIS)

Sharpe, H.N.; Strangway, D.W.

1976-01-01

Recent planetary probes have performed in situ measurements of the magnetic fields of all the terrestrial planets. Consideration is given to the origin of these fields, with attention to the equilibrium-- condensation hypothesis for the formation of the solar system. In particular, it is shown that Mercury's present day magnetic field could have been acquired during or shortly after a cold accretion or that it could be due to a presently operating dynamo, resulting from a 'hot evolution'. Two parameters which would help to distinguish between these possibilities are the present-day surface heat flow and the moment of inertia

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.

Future Mars geophysical observatories for understanding its internal structure, rotation, and evolution

Science.gov (United States)

Dehant, Veronique; Banerdt, Bruce; Lognonné, Philippe; Grott, Matthias; Asmar, Sami; Biele, Jens; Breuer, Doris; Forget, François; Jaumann, Ralf; Johnson, Catherine; Knapmeyer, Martin; Langlais, Benoit; Le Feuvre, Mathieu; Mimoun, David; Mocquet, Antoine; Read, Peter; Rivoldini, Attilio; Romberg, Oliver; Schubert, Gerald; Smrekar, Sue; Spohn, Tilman; Tortora, Paolo; Ulamec, Stephan; Vennerstrøm, Susanne

2012-08-01

Our fundamental understanding of the interior of the Earth comes from seismology, geodesy, geochemistry, geomagnetism, geothermal studies, and petrology. For the Earth, measurements in those disciplines of geophysics have revealed the basic internal layering of the Earth, its dynamical regime, its thermal structure, its gross compositional stratification, as well as significant lateral variations in these quantities. Planetary interiors not only record evidence of conditions of planetary accretion and differentiation, they exert significant control on surface environments. We present recent advances in possible in-situ investigations of the interior of Mars, experiments and strategies that can provide unique and critical information about the fundamental processes of terrestrial planet formation and evolution. Such investigations applied on Mars have been ranked as a high priority in virtually every set of European, US and international high-level planetary science recommendations for the past 30 years. New seismological methods and approaches based on the cross-correlation of seismic noise by two seismic stations/landers on the surface of Mars and on joint seismic/orbiter detection of meteorite impacts, as well as the improvement of the performance of Very Broad-Band (VBB) seismometers have made it possible to secure a rich scientific return with only two simultaneously recording stations. In parallel, use of interferometric methods based on two Earth-Mars radio links simultaneously from landers tracked from Earth has increased the precision of radio science experiments by one order of magnitude. Magnetometer and heat flow measurements will complement seismic and geodetic data in order to obtain the best information on the interior of Mars. In addition to studying the present structure and dynamics of Mars, these measurements will provide important constraints for the astrobiology of Mars by helping to understand why Mars failed to sustain a magnetic field, by

Planetary Biology and Microbial Ecology: Molecular Ecology and the Global Nitrogen cycle

Science.gov (United States)

Nealson, Molly Stone (Editor); Nealson, Kenneth H. (Editor)

1993-01-01

This report summarizes the results of the Planetary Biology and Molecular Ecology's summer 1991 program, which was held at the Marine Biological Laboratory in Woods Hole, Massachusetts. The purpose of the interdisciplinary PBME program is to integrate, via lectures and laboratory work, the contributions of university and NASA scientists and student interns. The goals of the 1991 program were to examine several aspects of the biogeochemistry of the nitrogen cycle and to teach the application of modern methods of molecular genetics to field studies of organisms. Descriptions of the laboratory projects and protocols and abstracts and references of the lectures are presented.

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.

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)

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, ...

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

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.

ESTEC/Geovusie/ILEWG planetary student design workshop: a teacher training perspective

Science.gov (United States)

Preusterink, Jolanda; Foing, Bernard H.; Kaskes, Pim

An important role for education is to inform and create the right skills for people to develop their own vision, using their talents to the utmost and inspire others to learn to explore in the future. Great effort has been taken to prepare this interactive design workshop thoroughly. Three days in a row, starting with presentations of Artscience The Hague to ESA colleagues, followed by a Planetary research Symposium in Amsterdam and a student design workshop at the end complemented a rich environment with the focus on Planetary exploration. The design workshop was organised by GeoVUsie students, with ESTEC and ILEWG support for tutors and inviting regional and international students to participate in an interactive workshop to design 5 Planetary Missions, with experts sharing their expertise and knowhow on specific challenging items: 1. Mercury - Post BepiColombo (with Sébastien Besse, ESA) 2. Moon South Pole Mission (with Bernard Foing, ESA) 3. Post-ExoMars - In search for Life on Mars (with Jorge Vago, ESA) 4. Humans in Space - Mars One investigated(with Arno Wielders, Space Horizon) 5. Europa - life on the icy moon of Jupiter? (with Bert Vermeersen, TU Delft) Lectures were given for more than 150 geology students at the symposium “Moon, Mars and More” at VU university, Amsterdam (organized by GeoVUsie earth science students). All students were provided with information before and at start for designing their mission. After the morning session there was a visit to the exhibition at The Erasmus Facility - ESTEC to inspire them even more with real artifacts of earlier and future missions into space. After this visit they prepared their final presentations, with original results, with innovative ideas and a good start to work out further in the future. A telescope session for geology students had been organized indoor due to rain. A follow-up visit to the nearby public Copernicus observatory was planned for another clear sky occasion. The interactive character

Planetary wave-gravity wave interactions during mesospheric inversion layer events

Science.gov (United States)

Ramesh, K.; Sridharan, S.; Raghunath, K.; Vijaya Bhaskara Rao, S.; Bhavani Kumar, Y.

2013-07-01

lidar temperature observations over Gadanki (13.5°N, 79.2°E) show a few mesospheric inversion layer (MIL) events during 20-25 January 2007. The zonal mean removed SABER temperature shows warm anomalies around 50°E and 275°E indicating the presence of planetary wave of zonal wave number 2. The MIL amplitudes in SABER temperature averaged for 10°N-15°N and 70°E-90°E show a clear 2 day wave modulation during 20-28 January 2007. Prior to 20 January 2007, a strong 2day wave (zonal wave number 2) is observed in the height region of 80-90 km and it gets largely suppressed during 20-26 January 2007 as the condition for vertical propagation is not favorable, though it prevails at lower heights. The 10 day mean zonal wind over Tirunelveli (8.7°N, 77.8°E) shows deceleration of eastward winds indicating the westward drag due to wave dissipation. The nightly mean MF radar observed zonal winds show the presence of alternating eastward and westward winds during the period of 20-26 January 2007. The two dimensional spectrum of Rayleigh lidar temperature observations available for the nights of 20, 22, and 24 January 2007 shows the presence of gravity wave activity with periods 18 min, 38 min, 38 min, and vertical wavelengths 6.4 km, 4.0 km, 6.4 km respectively. From the dispersion relation of gravity waves, it is inferred that these waves are internal gravity waves rather than inertia gravity waves with the horizontal phase speeds of ~40 m/s, ~37 m/s, and ~50 m/s respectively. Assuming the gravity waves are eastward propagating waves, they get absorbed only in the eastward local wind fields of the planetary wave thereby causing turbulence and eddy diffusion which can be inferred from the estimation of large drag force due to the breaking of gravity wave leading to the formation of large amplitude inversion events in alternate nights. The present study shows that, the mesospheric temperature inversion is caused mainly due to the gravity wave breaking and the inversion

New Understanding of Mercury's Magnetosphere from MESSENGER'S First Flyby

Science.gov (United States)

Slavin, James A.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Gold, Robert E.; Ho, George C.; Killen, M.; Korth, Haje;

For the love of Earth: Report of the commission on developing countries and the changes in planetary environments

International Nuclear Information System (INIS)

1992-01-01

A purely third-world program for studying changes in the planetary environment is proposed. This program rejects the idea that world ecological problems can be solved by simply readjusting the economies of developed countries, and affirms that sustainable development requires more fundamental modifications. A sustainable future is advocated on the basis of equity, economy, and ecology. The work conducted by the commission proposing the program is reviewed. This work rests on three basic propositions: that the problems of the planetary environment can be catastrophic for a number of developing countries; that the points of view of third-world countries must be integrated into any international program concerned with changes in the planetary environment; and that the social problems linked to such questions must be understood and resolved. The work presented is the result of a 10-month study program in the Caribbean and Central America, South America, Africa, South Asia, and Southeast Asia. The first part of the review describes the point of view of those countries on the crisis in the planetary environment and development, and its national and global causes. The second part concerns the roles, problems, and possibilities of social research on the questions of environment and development, in particular those appropriate to the developing world. The third part exposes the research program itself, including poverty, abundance, and needs; economic order and modes of development; political order; systems and technologies; and processes of cultural evolution. 151 refs

Geosciences: An Open Access Journal on Earth and Planetary Sciences and Their Interdisciplinary Approaches

Directory of Open Access Journals (Sweden)

Jesus Martinez-Frias

2011-05-01

Full Text Available On behalf of the Editorial Board and the editorial management staff of MDPI, it is my great pleasure to introduce this new journal Geosciences. Geosciences is an international, peer-reviewed open access journal, which publishes original papers, rapid communications, technical notes and review articles, and discussions about all interdisciplinary aspects of the earth and planetary sciences. Geosciences may also include papers presented at scientific conferences (proceedings or articles on a well defined topic assembled by individual editors or organizations/institutions (special publications.

A highly polarized hydrogen/deuterium internal gas target embedded in a toroidal magnetic spectrometer

International Nuclear Information System (INIS)

Cheever, D.; Ihloff, E.; Kelsey, J.; Kolster, H.; Meitanis, N.; Milner, R.; Shinozaki, A.; Tsentalovich, E.; Zwart, T.; Ziskin, V.; Xiao, Y.; Zhang, C.

2006-01-01

A polarized hydrogen/deuterium internal gas target has been constructed and operated at the internal target region of the South Hall Ring (SHR) of the MIT-Bates Linear Accelerator Center to carry out measurements of spin-dependent electron scattering at 850MeV. The target used an Atomic Beam Source (ABS) to inject a flux of highly polarized atoms into a thin-walled, coated storage cell. The polarization of the electron beam was determined using a Compton laser backscattering polarimeter. The target polarization was determined using well-known nuclear reactions. The ABS and storage cell were embedded in the Bates Large Acceptance Toroidal Spectrometer (BLAST), which was used to detect scattered particles from the electron-target interactions. The target has been designed to rapidly (∼8h) switch operation from hydrogen to deuterium. Further, this target was the first to be operated inside a magnetic spectrometer in the presence of a magnetic field exceeding 2kG. An ABS intensity 2.5x10 16 at/s and a high polarization (∼70%) inside the storage cell have been achieved. The details of the target design and construction are described here and the performance over an 18 month period is reported

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.

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 ...

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...

Exploration of Icy Moons in the Outer Solar System: Updated Planetary Protection Requirements for Missions to Enceladus and Europa

Science.gov (United States)

Rummel, J. D.; Race, M. S.

2016-12-01

Enceladus and Europa are bodies with icy/watery environments and potential habitable conditions for life, making both of great interest in astrobiological studies of chemical evolution and /or origin of life. They are also of significant planetary protection concern for spacecraft missions because of the potential for harmful contamination during exploration. At a 2015 COSPAR colloquium in Bern Switzerland, international scientists identified an urgent need to establish planetary protection requirements for missions proposing to return samples to Earth from Saturn's moon Enceladus. Deliberations at the meeting resulted in recommended policy updates for both forward and back contamination requirements for missions to Europa and Enceladus, including missions sampling plumes originating from those bodies. These recently recommended COSPAR policy revisions and biological contamination requirements will be applied to future missions to Europa and Encealadus, particularly noticeable in those with plans for in situ life detection and sample return capabilities. Included in the COSPAR policy are requirementsto `break the chain of contact' with Europa or Enceladus, to keep pristine returned materials contained, and to complete required biohazard analyses, testing and/or sterilization upon return to Earth. Subsequent to the Bern meeting, additional discussions of Planetary Protection of Outer Solar System bodies (PPOSS) are underway in a 3-year study coordinated by the European Science Foundation and involving multiple international partners, including Japan, China and Russia, along with a US observer. This presentation will provide science and policy updates for those whose research or activities will involve icy moon missions and exploration.

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...

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.

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.)

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...

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.

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.

Modeling of magnetic particle orientation in magnetic powder injection molding

Science.gov (United States)

Doo Jung, Im; Kang, Tae Gon; Seul Shin, Da; Park, Seong Jin

2018-03-01

The magnetic micro powder orientation under viscous shear flow has been analytically understood and characterized into a new analytical orientation model for a powder injection molding process. The effects of hydrodynamic force from the viscous flow, external magnetic force and internal dipole-dipole interaction were considered to predict the orientation under given process conditions. Comparative studies with a finite element method proved the calculation validity with a partial differential form of the model. The angular motion, agglomeration and magnetic chain formation have been simulated, which shows that the effect of dipole-dipole interaction among powders on the orientation state becomes negligible at a high Mason number condition and at a low λ condition (the ratio of external magnetic field strength and internal magnetic moment of powder). Our developed model can be very usefully employed in the process analysis and design of magnetic powder injection molding.

Magnetic fields and uniformity of radio frequency power deposition in low-frequency inductively coupled plasmas with crossed internal oscillating currents

International Nuclear Information System (INIS)

Tsakadze, E.L.; Ostrikov, K.; Tsakadze, Z.L.; Vladimirov, S.V.; Xu, S.

2004-01-01

Radial and axial distributions of magnetic fields in a low-frequency (∼460 kHz) inductively coupled plasma source with two internal crossed planar rf current sheets are reported. The internal antenna configuration comprises two orthogonal sets of eight alternately reconnected parallel and equidistant copper litz wires in quartz enclosures and generates three magnetic (H z , H r , and H φ ) and two electric (E φ and E r ) field components at the fundamental frequency. The measurements have been performed in rarefied and dense plasmas generated in the electrostatic (E) and electromagnetic (H) discharge modes using two miniature magnetic probes. It is shown that the radial uniformity and depth of the rf power deposition can be improved as compared with conventional sources of inductively coupled plasmas with external flat spiral ('pancake') antennas. Relatively deeper rf power deposition in the plasma source results in more uniform profiles of the optical emission intensity, which indicates on the improvement of the plasma uniformity over large chamber volumes. The results of the numerical modeling of the radial magnetic field profiles are found in a reasonable agreement with the experimental data

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

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.

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.

International cooperation in planetary exploration - Past success and future prospects

Science.gov (United States)

Rosendhal, Jeffrey D.

1987-01-01

A review is given of the ways in which the National Aeronautics and Space Administration (NASA) has participated in international efforts to explore the solar system. Past examples of successful international cooperative programs are described. Prospects for future cooperative efforts are discussed with emphasis placed on current events, issues, and trends which are likely to affect possibilities for cooperation over the next 5 to 10 years. Key factors which will play a major role in shaping future prospects for cooperation include the move towards balancing the budget in the United States and the impact of the Challenger accident on the NASA program.

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

Total internal reflection effect on gyrotropic interface

Science.gov (United States)

Glushchenko, Alexander G.; Glushchenko, Eugene P.; Zhukov, Sergey V.

2018-02-01

This article considers the physical features of total internal reflection at gyrotropic and isotropic interfaces for two cases: electrical gyrotropy (plasma) and magnetic gyrotropy (ferrite). It is shown that the plasma magnetization may lead to the formation of the total internal reflection effect, which does not occur in isotropic plasma. The threshold values of the magnetic field, which are necessary for the total internal reflection effect, are determined. The total internal reflection effect on a ferrite-dielectric interface for waves emanating from different angles is observed in various frequency ranges and magnetization fields. The study points out the possibility of changing the total internal reflection angle value in large limits due to a change in the external magnetic field magnitude. The calculation results of the total internal reflection angle dependence on the external magnetic field magnitude are presented. The formulas are elaborated for calculating the total internal reflection angles of different interfaces for gyrotropic and isotropic media. The generalized formulas are defined for calculating the Doppler effect in the gyrotropic media. The study demonstrates how the velocity of the media interface affects the limiting angle of total internal refection.

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...

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.

An internal magnetic field strategy to reuse pulverized active materials for high performance: a magnetic three-dimensional ordered macroporous TiO2/CoPt/α-Fe2O3 nanocomposite anode.

Science.gov (United States)

Tang, Yiping; Hong, Liang; Li, Jiquan; Hou, Guangya; Cao, Huazhen; Wu, Liankui; Zheng, Guoqu; Wu, Qingliu

2017-05-09

A ferromagnetic three-dimensional ordered macroporous TiO 2 /CoPt/α-Fe 2 O 3 (3DOMTCF) nanocomposite was synthesized via a sol-gel approach templated by poly(methyl methacrylate) (PMMA) microspheres. After magnetization, it exhibited an extremely high reversible capacity and a long cycle life, which were ascribed to the internal magnetic field for reusing pulverized active materials and its unique structure.

Local and social facets of planetary boundaries: right to nutrients

International Nuclear Information System (INIS)

Kahiluoto, Helena; Kuisma, Miia; Kuokkanen, Anna; Mikkilä, Mirja; Linnanen, Lassi

2015-01-01

Anthropogenic nutrient flows exceed the planetary boundaries. The boundaries and the current excesses vary spatially. Such variations have both an ecological and a social facet. We explored the spatial variation using a bottom-up approach. The local critical boundaries were determined through the current or accumulated flow of the preceding five years before the planetary boundary criteria were met. Finland and Ethiopia served as cases with contrasting ecology and wealth. The variation in excess depends on historical global inequities in the access to nutrients. Globally, the accumulated use per capita is 2300 kg reactive nitrogen (N r ) and 200 kg phosphorus (P). For Finland, the accumulated use per capita is 3400 kg N r and 690 kg P, whereas for Ethiopia, it is 26 kg N r and 12 kg P. The critical N boundary in Finland is currently exceeded by 40 kg cap −1 a −1 and the accumulated excess is 65 kg cap −1 a −1 , while the global current excess is 24 kg cap −1 a −1 and there is space in Ethiopia to increase even the accumulated flow. The critical P boundary is exceeded in Finland and (although less so) in Ethiopia, but for contrary reasons: (1) the excessive past inflow to the agrifood system in Finland and (2) the excessive outflow from the agrifood system triggered by deficits in inflow and waste management in Ethiopia. The critical boundaries set by Finnish marine systems are lower and those set by freshwaters are higher than the planetary boundaries downscaled per capita. The shift to dominance of internal loading in watercourses represents a tipping point. We conclude that food security within the safe boundaries requires global redistribution of nutrients in residues, soils and sediments and of rights to use nutrients. Bottom-up assessments reveal local dynamics that shed new light on the relevant boundary criteria and on estimates and remedies. (letter)

Inclusive Planetary Science Outreach and Education: a Pioneering European Experience

Science.gov (United States)

Galvez, A.; Ballesteros, F.; García-Frank, A.; Gil, S.; Gil-Ortiz, A.; Gómez-Heras, M.; Martínez-Frías, J.; Parro, L. M.; Parro, V.; Pérez-Montero, E.; Raposo, V.; Vaquerizo, J. A.

2017-09-01

Abstract Universal access to space science and exploration for researchers, students and the public, regardless of physical abilities or condition, is the main objective of work by the Space Inclusive Network (SpaceIn). The purpose of SpaceIn is to conduct educational and communication activities on Space Science in an inclusive and accessible way, so that physical disability is not an impediment for participating. SpaceIn members aim to enlarge the network also by raising awareness among individuals such as undergraduate students, secondary school teachers, and members of the public with an interest and basic knowledge on science and astronomy. As part of a pilot experience, current activities are focused on education and outreach in the field of comparative Planetary Science and Astrobiology. Themes include the similarities and differences between terrestrial planets, the role of water and its interaction with minerals on their surfaces, the importance of internal thermal energy in shaping planets and moons and the implications for the appearance of life, as we know it, in our planet and, possibly, in other places in our Solar System and beyond. The topics also include how scientific research and space missions can shed light on these fundamental issues, such as how life appears on a planet, and thus, why planetary missions are important in our society, as a source of knowledge and inspiration. The tools that are used to communicate the concepts include talks with support of multimedia and multi-sensorial material (video, audio, tactile, taste, smell) and field trips to planetary analogue sites that are accessible to most members of the public, including people with some kind of disability. The field trips help illustrate scientific concepts in geology e.g. lava formations, folds, impact features, gullies, salt plains; biology, e.g. extremophiles, halophites; and exploration technology, e.g. navigation in an unknown environment, hazard and obstacle avoidance

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.

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

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

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.

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.

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.

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.

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

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.

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.

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.

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

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.

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...

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

Science.gov (United States)

Plescia, J. B.

1984-01-01