WorldWideScience

Sample records for icy galilean satellites

  1. Ion pick-up near the icy Galilean satellites

    Science.gov (United States)

    Volwerk, M.; Khurana, K. K.

    2010-12-01

    The ion pick-up near the icy Galilean satellites is studied using ion cyclotron waves. Using Galileo magnetometer data, we show evidence for the existence of ion cyclotron waves, which are generated by pick-up of freshly ionized particles. Near Europa, in the wake various kinds of ions are detected, which were already predicted to be present on the moon. Upstream of the moon there is evidence for water ion pick-up, which could facilitate the slow down of the plasma flow. Ganymede shows evidence for either water or oxygen pick up on the flanks of the magnetosphere. Callisto shows indication of hydrogen pick-up from its atmosphere.

  2. Sounding of Icy Galilean Satellites by Surface Observatories

    Science.gov (United States)

    Khurana, K. K.; Banerdt, W. B.; Johnson, T. V.; Russell, C. T.; Kivelson, M. G.; Davis, P. M.; Vidale, J. E.

    2001-01-01

    Several independent geological and geophysical investigations suggest that Europa and Ganymede contain subsurface oceans. Using Jupiter's rotating magnetic field as a primary signal, the magnetometer experiment onboard Galileo has measured secondary induction signals emanating from Europa, Ganymede, and surprisingly Callisto. The strong electromagnetic induction from these moons suggests that large global electrical conductors are located just below their icy crusts. A detailed analysis reveals that global salty oceans with salinity similar to the Earth's ocean and thicknesses in the range of approx. 6-100 kms can explain the induction observed by the Galileo magnetometer. Additional information is contained in the original extended abstract.

  3. Interpretation of Radar Data from the Icy Galilean Satellites and Triton

    Science.gov (United States)

    Gurrola, Eric Michael

    1995-01-01

    We extend Eshleman's (Science 234, 1986, 587-590) analysis of an icy buried crater model and show that it can explain anomalous 3.5 and 13 cm-lambda radar echoes from the icy Galilean satellites- -radar albedos sigma~ 0.7 -2.6, circular and linear polarization ratios mu C~1.5 and mu L~0.5, and Doppler spectra with cosmTheta scattering law exponents m~1 -2. The model hypothesizes that radio waves are totally internally reflected N times from the walls of buried craters --tens of meters in radii with a water-ice overburden of permittivity varepsilon_1~3.2 varepsilon_0 that is larger than the permittivity varepsilon_2 of the material (probably porous ice) below the crater walls--and are brought to a focus, appearing to come from annular "glory halos" inside the craters, which break up into several coherent glints, each of azimuthal extent H, filling the halo to fraction F. We use geometrical and wave optics to include effects not accounted for by Eshleman, including: the ice overburden, arbitrary crater position, and crater shadowing. The values N = 3 and varepsilon_2/varepsilon _1 = 0.63 give mu_ {C} = 1.6, muL = 0.4, m = 1.9, and spectra that agree well with the general trends in the observations. With FH/ lambda = 10, the areal densities of buried craters on the three satellites required to fit the observed radar albedos are, 0.38, 0.21, and 0.10 for Europa, Ganymede, and Callisto. We determine that Triton's N_2 atmosphere's surface pressure is 1.4 +/- 0.1 Pa and "equivalent isothermal temperature" is 42 +/- 4 K using least squares inversion of the 3.6 and 13 cm-lambda Voyager 2 radio occultation phase data with an exponential model of the atmospheric contribution to the phase (1.7 rad at 3.6 cm-lambda in lower 60 km) and a polynomial model of the nonlinear phase drift (1 rad per 100 km altitude) of the Voyager ultrastable oscillator (USO). Assuming vapor pressure equilibrium between the N_2 gas and ice, the surface temperature is 37.5 +/- 0.5 K, which, together

  4. The Galilean Satellites

    Science.gov (United States)

    1998-01-01

    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft acquired the Io and Ganymede images in June 1996, the Europa images in September 1996, and the Callisto images in November 1997.Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission

  5. Galilean Satellite Atmospheres and Aurora in Eclipse

    Science.gov (United States)

    Retherford, Kurt

    Io, Europa, and Ganymede all demonstrate unique displays of auroral and atmospheric emis-sions, and all three routinely pass into Jupiter's shadow. Callisto on the other hand very rarely passes into eclipse by Jupiter, and no auroral emissions have been detected there to date. In eclipse, Io's dayside surface temperature is known to rapidly drop from 120 K to 90 K, which is sufficient to diminish the sublimation component of the atmosphere across most of the surface and possibly results in an atmosphere mostly made directly from volcanos. While surface sputtering by magnetospheric particles is likely the primary source of the icy satel-lite atmospheres for Ganymede and Europa, little observational evidence is available regarding the relative contribution of the smaller sublimation components and potential changes in icy surface temperatures near the sub-solar point in eclipse. Eclipse observations of auroral emis-sions generally have the ability to correlate changes in the atmosphere with changes in surface temperature and/or photochemistry. They also offer the practical advantage of little or no confusion from reflected sunlight. We will review the present auroral observations available for investigating the behavior of Galilean satellite atmospheres in eclipse.

  6. Galilean Satellite Ephemerides E5

    Science.gov (United States)

    Lieske, J. H.

    1997-01-01

    New ephemerides of Jupiter's Galilean Satelites are produced from an analysis of CCD astrometric data, Voyager-mission optical navigation images, mutual event observations, photographic plates, and eclipse timing obeservations.

  7. Improved ephemerides of the Galilean satellites

    Science.gov (United States)

    Lieske, J. H.

    1980-01-01

    Over 4800 earth-based observations of Jupiter's Galilean satellites have been analyzed in order to develop improved ephemerides of the satellites for the Voyager mission, using the new theory of motion of the Galilean satellites. Included are over 1700 eclipses of the satellites by Jupiter spanning the interval 1878-1974, 85 mutual events (eclipses and occultations) observed in 1973, and over 2900 exposures on photographic plates from 1967-1978. The resulting ephemerides (labeled E-2) were employed for the Voyager I encounter and are in error by less than 200 km at the time of Jupiter close approach. A very small (0.066 deg) amplitude of the Laplacian free libration is indicated by the data.

  8. Coordinates of features on the Galilean satellites

    Science.gov (United States)

    Davies, M. E.; Katayama, F. Y.

    1981-09-01

    Control nets of the four Galilean satellites have been established photogrammetrically from pictures taken by the two Voyager spacecraft during their flybys of Jupiter in 1979. Coordinates of 504 points on Io, 112 points on Europa, 1547 points on Ganymede, and 439 points on Callisto are listed. Selected points are identified on U.S. Geological Survey maps of the satellites. Measurements of these points were made on 234 pictures of Io, 115 pictures of Europa, 282 pictures of Ganymede, and 200 pictures of Callisto. The systems of longitude were defined by craters on Europa, Ganymede, and Callisto. Preliminary solutions have been found for the directions of the axes of rotation of the Galilean satellites. New mean radii have been determined as 1815 + or - 5 km for Io, 1569 + or - 10 km for Europa, 2631 + or - 10 km for Ganymede, and 2400 + or - 10 km for Callisto.

  9. Orbital Perturbations of the Galilean Satellites During Planetary Encounters

    CERN Document Server

    Deienno, R; Vokrouhlicky, D; Yokoyama, T

    2014-01-01

    The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present Solar System, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites, and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorny & Morbidelli (2012) that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly af...

  10. Spectral properties of icy satellites

    Science.gov (United States)

    Stephan, Katrin; Jaumann, Ralf; Wagner, Roland; Clark, Roger; Cruikshank, Dale; Brown, Robert; Roatsch, Thomas; Buratti, Bonnie; Matson, Dennis; Dalle Ore, Cristina; Filacchione, Gianrico; Capaccioni, Fabrizio; Nicholson, Phil; Baines, Kevin; Sotin, Christoph

    2015-08-01

    Since 2004 Cassini is orbiting the Saturnian system with its instruments investigating the chemical and physical properties of Saturn ‘s atmosphere, its magnetosphere, its numerous satellites and rings. The VIMS instrument onboard Cassini enables not only to identify the Saturn satellites’ compositional units but also to map their distribution across the surfaces, to relate their location and extension to specific geological and/or geomorphological surface features and to characterize surface alterations induced by the space environment. Although, the VIMS spectra of the Saturnian satellites’ surfaces are dominated by H2O-ice, its distribution and physical characteristics differ distinctly from one satellite to the other. Global hemispherical differences are mostly related to the satellite’s orbital position within the Saturnian system, i.e. the distance to Saturn and its E ring, with particles originating from Saturn’s magnetosphere and/or the ice grains coming from the E ring impacting their surfaces. Often, these hemispherical differences are characterized by a dark non-icy contaminant more concentrated on their trailing hemispheres, while the more water ice-rich leading hemispheres appear covered by fresh material ejected by an impact event and/or by impacting E-ring particles. Tethys, however, situated closer to Enceladus and the E ring and deeper within Saturn’s magnetosphere, shows a more complex pattern. Compositional changes on a regional and local scale could be identified and related to the geological processes, i.e. impact cratering, tectonics, and erosion. Particularly, young impact craters and tectonic features reveal clean H2O ice of relatively large grain size while the “fresh” (unaltered) surface material offers a unique view into the crustal properties and evolution of its satellite. Whereas, prominent graben systems on Dione and Rhea are characterized by a pronounced ice signature - Ithaca Chasma on Tethys is barely recognizable

  11. Space Weathering on Icy Satellites in the Outer Solar System

    Science.gov (United States)

    Clark, R. N.; Perlman, Z.; Pearson, N.; Cruikshank, D. P.

    2014-01-01

    Space weathering produces well-known optical effects in silicate minerals in the inner Solar System, for example, on the Moon. Space weathering from solar wind and UV (ultraviolet radiation) is expected to be significantly weaker in the outer Solar System simply because intensities are low. However, cosmic rays and micrometeoroid bombardment would be similar to first order. That, combined with the much higher volatility of icy surfaces means there is the potential for space weathering on icy outer Solar System surfaces to show optical effects. The Cassini spacecraft orbiting Saturn is providing evidence for space weathering on icy bodies. The Cassini Visible and Infrared Mapping Spectrometer (VIMS) instrument has spatially mapped satellite surfaces and the rings from 0.35-5 microns and the Ultraviolet Imaging Spectrograph (UVIS) instrument from 0.1 to 0.2 microns. These data have sampled a complex mixing space between H2O ice and non-ice components and they show some common spectral properties. Similarly, spectra of the icy Galilean satellites and satellites in the Uranian system have some commonality in spectral properties with those in the Saturn system. The UV absorber is spectrally similar on many surfaces. VIMS has identified CO2, H2 and trace organics in varying abundances on Saturn's satellites. We postulate that through the spatial relationships of some of these compounds that they are created and destroyed through space weathering effects. For example, the trapped H2 and CO2 observed by VIMS in regions with high concentrations of dark material may in part be space weathering products from the destruction of H2O and organic molecules. The dark material, particularly on Iapetus which has the highest concentration in the Saturn system, is well matched by space-weathered silicates in the .4 to 2.6 micron range, and the spectral shapes closely match those of the most mature lunar soils, another indicator of space weathered material.

  12. Dust en-route to Jupiter and the Galilean satellites

    CERN Document Server

    Krüger, H; Krueger, Harald; Gruen, Eberhard

    2002-01-01

    Spacecraft investigations during the last ten years have vastly improved our knowledge about dust in the Jovian system. All Galilean satellites, and probably all smaller satellites as well, are sources of dust in the Jovian system. In-situ measurements with the dust detectors on board the Ulysses and Galileo spacecraft have for the first time demonstrated the electromagnetic interaction of charged dust grains with the interplanetary magnetic field and with a planetary magnetosphere. Jupiter's magnetosphere acts as a giant mass-velocity spectrometer for charged 10-nanometer dust grains. These dust grains are released from Jupiter's moon Io with typical rate of 1 kg s^1. The dust streams probe the plasma conditions in the Io plasma torus and can be used as a potential monitor of Io's volcanic plume activity. The other Galilean satellites are surrounded by tenuous impact-generated clouds of mostly sub-micrometer ejecta grains. Galileo measurements have demonstrated that impact-ejecta derived from hypervelocity i...

  13. Thermal Conductivity Measurements on Icy Satellite Analogs

    Science.gov (United States)

    Javeed, Aurya; Barmatz, Martin; Zhong, Fang; Choukroun, Mathieu

    2012-01-01

    With regard to planetary science, NASA aspires to: "Advance scientific knowledge of the origin and history of the solar system, the potential for life elsewhere, and the hazards and resources present as humans explore space". In pursuit of such an end, the Galileo and Cassini missions garnered spectral data of icy satellite surfaces implicative of the satellites' structure and material composition. The potential for geophysical modeling afforded by this information, coupled with the plausibility of life on icy satellites, has pushed Jupiter's Europa along with Saturn's Enceladus and Titan toward the fore of NASA's planetary focus. Understanding the evolution of, and the present processes at work on, the aforementioned satellites falls squarely in-line with NASA's cited goal.

  14. Orbital perturbations of the Galilean satellites during planetary encounters

    Energy Technology Data Exchange (ETDEWEB)

    Deienno, Rogerio; Nesvorný, David [Southwest Research Institute, Boulder, CO (United States); Vokrouhlický, David [Institute of Astronomy, Charles University, Prague (Czech Republic); Yokoyama, Tadashi, E-mail: rogerio.deienno@gmail.com [Universidade Estadual Paulista, Rio Claro, SP (Brazil)

    2014-08-01

    The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present solar system, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here, we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorný and Morbidelli that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly affected. In the other two, the orbital eccentricities of all moons were excited by encounters, Callisto's semimajor axis changed, and, in a large fraction of trials, the Laplace resonance of the inner three moons was disrupted. The subsequent evolution by tides damps eccentricities and can recapture the moons in the Laplace resonance. A more important constraint is represented by the orbital inclinations of the moons, which can be excited during the encounters and not appreciably damped by tides. We find that one instability case taken from Nesvorný and Morbidelli clearly does not meet this constraint. This shows how the regular satellites of Jupiter can be used to set limits on the properties of encounters in the jumping-Jupiter model, and help us to better understand how the early solar system evolved.

  15. Orbital Perturbations of the Galilean Satellites during Planetary Encounters

    Science.gov (United States)

    Deienno, Rogerio; Nesvorný, David; Vokrouhlický, David; Yokoyama, Tadashi

    2014-08-01

    The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present solar system, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here, we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorný & Morbidelli that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly affected. In the other two, the orbital eccentricities of all moons were excited by encounters, Callisto's semimajor axis changed, and, in a large fraction of trials, the Laplace resonance of the inner three moons was disrupted. The subsequent evolution by tides damps eccentricities and can recapture the moons in the Laplace resonance. A more important constraint is represented by the orbital inclinations of the moons, which can be excited during the encounters and not appreciably damped by tides. We find that one instability case taken from Nesvorný & Morbidelli clearly does not meet this constraint. This shows how the regular satellites of Jupiter can be used to set limits on the properties of encounters in the jumping-Jupiter model, and help us to better understand how the early solar system evolved.

  16. Convection in Icy Satellites: Implications for Habitability and Planetary Protection

    Science.gov (United States)

    Barr, A. C.; Pappalardo, R. T.

    2004-01-01

    Solid-state convection and endogenic resurfacing in the outer ice shells of the icy Galilean satellites (especially Europa) may contribute to the habitability of their internal oceans and to the detectability of any biospheres by spacecraft. If convection occurs in an ice I layer, fluid motions are confined beneath a thick stagnant lid of cold, immobile ice that is too stiff to participate in convection. The thickness of the stagnant lid varies from 30 to 50% of the total thickness of the ice shell, depending on the grain size of ice. Upward convective motions deliver approximately 10(exp 9) to 10(exp 13) kg yr(sup -1) of ice to the base of the stagnant lid, where resurfacing events driven by compositional or tidal effects (such as the formation of domes or ridges on Europa, or formation of grooved terrain on Ganymede) may deliver materials from the stagnant lid onto the surface. Conversely, downward convective motions deliver the same mass of ice from the base of the stagnant lid to the bottom of the satellites ice shells. Materials from the satellites surfaces may be delivered to their oceans by downward convective motions if material from the surface can reach the base of the stagnant lid during resurfacing events. Triggering convection from an initially conductive ice shell requires modest amplitude (a few to tens of kelvins) temperature anomalies to soften the ice to permit convection, which may require tidal heating. Therefore, tidal heating, compositional buoyancy, and solid-state convection in combination may be required to permit mass transport between the surfaces and oceans of icy satellites. Callisto and probably Ganymede have thick stagnant lids with geologically inactive surfaces today, so forward contamination of their surfaces is not a significant issue. Active convection and breaching of the stagnant lid is a possibility on Europa today, so is of relevance to planetary protection policy.

  17. Hubble Gallery of Jupiter's Galilean Satellites

    Science.gov (United States)

    1995-01-01

    This is a Hubble Space Telescope 'family portrait' of the four largest moons of Jupiter, first observed by the Italian scientist Galileo Galilei nearly four centuries ago. Located approximately one-half billion miles away, the moons are so small that, in visible light, they appear as fuzzy disks in the largest ground-based telescopes. Hubble can resolve surface details seen previously only by the Voyager spacecraft in the early 1980s. While the Voyagers provided close-up snapshots of the satellites, Hubble can now follow changes on the moons and reveal other characteristics at ultraviolet and near-infrared wavelengths.Over the past year Hubble has charted new volcanic activity on Io's active surface, found a faint oxygen atmosphere on the moon Europa, and identified ozone on the surface of Ganymede. Hubble ultraviolet observations of Callisto show the presence of fresh ice on the surface that may indicate impacts from micrometeorites and charged particles from Jupiter's magnetosphere.Hubble observations will play a complementary role when the Galileo spacecraft arrives at Jupiter in December of this year.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  18. Radio Sounding Techniques for the Galilean Icy Moons and their Jovian Magnetospheric Environment

    Science.gov (United States)

    Green, James L.; Markus, Thursten; Fung, Shing F.; Benson, Robert F.; Reinich, Bodo W.; Song, Paul; Gogineni, S. Prasad; Cooper, John F.; Taylor, William W. L.; Garcia, Leonard

    2004-01-01

    Radio sounding of the Earth's topside ionosphere and magnetosphere is a proven technique from geospace missions such as the International Satellites for Ionospheric Studies (ISIS) and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE). Application of this technique to Jupiter's icy moons and the surrounding Jovian magnetosphere will provide unique remote sensing observations of the plasma and magnetic field environments and the subsurface conductivities, of Europa, Ganymede, and Callisto. Spatial structures of ionospheric plasma above the surfaces of the moons vary in response to magnetic-field perturbations from (1) magnetospheric plasma flows, (2) ionospheric currents from ionization of sputtered surface material, and (3) induced electric currents in salty subsurface oceans and from the plasma flows and ionospheric currents themselves. Radio sounding from 3 kHz to 10 MHz can provide the global electron densities necessary for the extraction of the oceanic current signals and supplements in-situ plasma and magnetic field measurements. While radio sounding requires high transmitter power for subsurface sounding, little power is needed to probe the electron density and magnetic field intensity near the spacecraft. For subsurface sounding, reflections occur at changes in the dielectric index, e.g., at the interfaces between two different phases of water or between water and soil. Variations in sub-surface conductivity of the icy moons can be investigated by radio sounding in the frequency range from 10 MHz to 50 MHz, allowing the determination of the presence of density and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts. The detection of subsurface oceans underneath the icy crusts of the Jovian moons is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. Preliminary modeling results show that return signals are clearly distinguishable be&een an ice crust with a thickness of

  19. Galileo's first images of Jupiter and the Galilean satellites

    Science.gov (United States)

    Belton, M.J.S.; Head, J. W.; Ingersoll, A.P.; Greeley, R.; McEwen, A.S.; Klaasen, K.P.; Senske, D.; Pappalardo, R.; Collins, G.; Vasavada, A.R.; Sullivan, R.; Simonelli, D.; Geissler, P.; Carr, M.H.; Davies, M.E.; Veverka, J.; Gierasch, P.J.; Banfield, D.; Bell, M.; Chapman, C.R.; Anger, C.; Greenberg, R.; Neukum, G.; Pilcher, C.B.; Beebe, R.F.; Burns, J.A.; Fanale, F.; Ip, W.; Johnson, T.V.; Morrison, D.; Moore, J.; Orton, G.S.; Thomas, P.; West, R.A.

    1996-01-01

    The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on lo. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution.

  20. Mass-radius relationships in icy satellites

    Science.gov (United States)

    Lupo, M. J.; Lewis, J. S.

    1979-01-01

    Using published laboratory data for H2O ice, a modeling technique was developed by which the bulk density, density and temperature profile, rotational moment of inertia, central pressure, and location of the rock-ice interface can all be obtained as a function of the radius, the heliocentric distance, and the silicate composition. Models of the interiors of Callisto, Ganymede, Europa, Rhea, and Titan are given, consistent with present mass and radius data. The radius and mass of spheres of ice under self-gravitation for two different temperature classes are given (103 and 77 deg K). Measurements of mass, radius and I/MR2 by spacecraft can be interpreted by this model to yield substantial information about the internal structure and the ice/rock ratio of the icy satellites of Jupiter and Saturn.

  1. Thermal migration of water on the Galilean satellites

    Energy Technology Data Exchange (ETDEWEB)

    Purves, N.G.; Pilcher, C.B.

    1980-01-01

    We have modeled the thermal migration of water on the Galilean satellites under the assumption of ballistic molecular trajectories. It is found that water migrating owing to solar radiation on an ice-covered satellite will build up in temperate latitudes, in general not reaching the poles. As much as 50 m of ice may have been lost by this process from the equatorial regions of Europa over the age of the solar system. The disappearance of patches of ice - for instance, the bright rays surrounding some impact craters - from the equatorial regions of Ganymede and Callisto may approach a value (the irreversible evaporation rate) three orders of magnitude larger than the net equatorial loss rate for ice-covered Europa. The presence of water ice pole caps on Ganymede extending to the latitudes at which thermal migration becomes important suggests that some process distributed an extensive, thin covering of water on the satellite, and that the equatorial regions were subsequently cleared by the thermal process.

  2. Compositional Impact of Io Volcanic Emissions on Jupiter's Magnetosphere and the Icy Galilean Moons

    Science.gov (United States)

    Cooper, John; Fegley, Bruce; Lipatov, Alexander; Richardson, John; Sittler, Edward

    2011-01-01

    The magnetospheric ion population of Jupiter is dominated by the 1000 kg/s of iogenic material constantly ejected by IO volcanism as neutral gas (approx. 1 kg/s goes out as high speed dust grains), subsequent atmospheric losses to the IO torus, and radial transport of torus ions throughout the magnetosphere. As that magnetosphere is greatly distended in radial size by the iogenic plasma loading, so are surfaces of the other Galilean moons also significantly, and perhaps even dominantly, affected by iogenic plasma bombardment, e.g. at the level up to 0.2 kg/s heavy ions (mostly O and S) onto Europa as per local plasma ion measurements. In comparison, cometary impacts onto IO deliver about 0.02 kg/s of impact ejecta to Europa via ballistic transfer through the Jupiter system. The magnetosphere of this system operates as a powerful engine to produce and transport ions from the IO source to the surfaces of these other moons, and any future orbiter missions to these moons must account for surface distributions of the iogenic material and its chemical effects before real assessments can be made of sensible chemical materials otherwise arising from primordial formation and subsequent evolution of these moons. This is a fundamental problem of space weathering that must be addressed for all planetary bodies with thin atmospheres and direct surface exposure to their space plasma environments. Long-standing debates from Galileo Orbiter measurements about the origins of hydrate sulfates at Europa present examples of this problem, as to whether the sulfates arise from oceanic minerals or from iogenic sulfur chemistry. Any orbiter or landed mission to Europa for astrobiological investigations would further need to separate the potential chemical biosignatures of life or its precursors from the highly abundant background of iogenic material. Although no single ion carries a tag identifying it as of iogenic or other origin, the elemental abundance distributions of ions to be

  3. On the Behavior of the Galilean Satellites in the Jumping Jupiter Scenario

    Science.gov (United States)

    Deienno, Rogerio; Nesvorný, D.; Yokoyama, T.

    2013-10-01

    The Nice model of the dynamical instability and migration of the giant planets can explain many properties of our present Solar System, and can be used to constrain its early architecture. In the jumping Jupiter version of the Nice model, required from the terrestrial planet constrains, Jupiter is involved in encounters with an ice giant. Here we study the survival of the Galilean satellites in the jumping Jupiter model. This is an important concern because the ice giant encounters, if deep enough, could dynamically interfere with the orbits of the Galilean satellites, and lead to implausible results. The jumping Jupiter models are taken from Nesvorný and Morbidelli 2012 (NM12). Our metodology in this study take into account the effects of the Sun, Jupiter's oblateness and obliquity, as well as the planetary close encounters tracked in NM12 upon the Galilean moons. We considered three instability cases that differed in the number and distribution of ice giant encounters with Jupiter. In each case, we considered 1000 realizations of the Galilean satellite system before the instability, and integrated the dynamical response of satellite orbits to ice giant encounters. We found that in one of the considered cases, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly disturbed. In the other two, the final orbital eccentricities were [0-0.2], and Callisto's semi-major axis ended within [22-30]Rj, while the other satellites kept their semi-major axis nearly constant. As Callisto's semi-major axis may vary as much, we also hint on the possibility that all four Galilean satellites were originally formed in a Laplace resonance, and Callisto was kicked out of it by encounters. These results: i) show that Galilean satellites are an important constrain on the planetary instability; ii) can check on the possibility to the Galilean system have been formed in a different configuration of seen today. Acknowledgement

  4. Bombardment History of the Galilean Satellites and Derived Ages

    Science.gov (United States)

    Neukum, G.; Wagner, R.; Wolf, U.; Head, J. W., III; Pappalardo, R.; Chapman, C. R.; Merline, W.; Belton, M. S.

    1997-07-01

    During the first seven Galileo flybys, high resolution imagery of the three Galilean moons, Europa, Ganymede and Callisto have been obtained. The new imaging data allow to measure crater diameters as small as ~ 100 m. In combination with Voyager data, size-frequency distribution characteristics in the size range of ~ 100 m to ~ 100 km have been determined. Crater distributions show steep slopes (cumulative index about -3) at smaller diameters on each satellite and are shallower at larger diameters, similar to what is seen on the Moon and the asteroids Gaspra and Ida. % % At D = 1 km, crater densities differ by about a factor of 10 between % average dark terrain of Galileo Regio and youngest bright resurfaced areas % on Ganymede. % Crater densities on the most heavily cratered regions on both Ganymede and Callisto are fairly comparable. On Europa, crater densities have turned out to be about a factor of 10 lower than on the youngest bright terrain in the Uruk Sulcus region of Ganymede. The similarity to crater size-frequency distributions found in the inner solar system suggests a similar origin of the projectiles, probably mainly stemming from the asteroid belt, and the impact rate on the Galilean satellites may have had a lunar-like decay with time. Under this assumption, absolute ages may be derived making use of the idea of the ''marker horizon'', i. e. formation of the youngest basins, such as Gilgamesh on Ganymede, about 3.8 b.y. ago. Thus, the most densely cratered dark terrains on both Ganymede and Callisto have likely ages of 4.1 - 4.3 b.y. Basins such as Neith (on Ganymede) or Adlinda (on Callisto) yield likely ages of about 3.9 b.y. Some areas on Europa may be as old as 3 - 3.3 b.y. Other scenarios based on values proposed for the present-day comet impact rate in the Jovian system with non-lunar-like flux time dependences are conceivable and would result in generally younger ages, possibly as young as 10 m.y. These young ages and impact rates for Europa

  5. Jupiter's Decametric Radio Emission and the Radiation Belts of Its Galilean Satellites.

    Science.gov (United States)

    Burns, J A

    1968-03-01

    Many of the observed properties of Jupiter's decametric radiation may be explained by postulation that the inner Galilean satellites of Jupiter have magnetic properties that strongly distort Jupiter's magnetic field in the region of each satellite. Charged particles from Jupiter's radiation belts are trapped by these distorted fields and emit synchrotron radiation.

  6. Eclipses and Occultations of Galilean Satellites Observed at Yunnan Observatory in 2003

    Institute of Scientific and Technical Information of China (English)

    Qing-Yu Peng; Beno(i)t Noyelles

    2007-01-01

    We describe and analyze observations of mutual events of Galilean satellites made at the Yunnan Observatory in February 2003 from CCD imaging for the first time in China.Astrometric positions were deduced from these photometric observations by modelling the relative motion and the photometry of the involved satellites during each event.

  7. The Saturn System's Icy Satellites: New Results from Cassini

    Science.gov (United States)

    Lopes-Gautier, Rosaly M.; Buratti, Bonnie; Hendrix, A. R.

    2008-01-01

    Cassini-Huygens is a multidisciplinary, international planetary mission consisting of an orbiting spacecraft and a probe. The Huygens probe successfully landed on Titan's surface on January 14, 2005, while the orbiter has performed observations of Saturn, its rings, satellites, and magnetosphere since it entered orbit around Saturn on July 1, 2004. The Cassini mission has been prolific in its scientific discoveries about the Saturn system. In this special section, we present new mission results with a focus on the 'icy satellites,' which we define as all Saturn's moons with the exception of Titan. The results included in this section have come out of the Cassini SOST--Satellites Orbiter Science Team--a multi-instrument and multidiscipline group that works together to better understand the icy satellites and their interactions with Saturn and its rings. Other papers included in this issue present ground-based observations and interior modeling of these icy moons.

  8. The Q Values of the Galilean Satellites and their Tidal Contributions to the Deceleration of Jupiter's Rotation

    Institute of Scientific and Technical Information of China (English)

    Hong Zhang; Cheng-Zhi Zhang

    2004-01-01

    The relationship between the k2/Q of the Galilean satellites and the k2J/QJ of Jupiter is derived from energy and momentum considerations. Calculations suggest that the Galilean satellites can be divided into two classes according to their Q values: Io and Ganymede have values between 10 and 50, while Europa and Callisto have values ranging from 200 to 700. The tidal contributions of the Galilean satellites to Jupiter's rotation are estimated. The main deceleration of Jupiter, which is about 99.04% of the total, comes from Io.

  9. Hydrocarbons on the Icy Satellites of Saturn

    Science.gov (United States)

    Cruikshank, Dale P.

    2010-01-01

    The Visible-Infrared Mapping Spectrometer on the Cassini Spacecraft has obtained spectral reflectance maps of the satellites of Saturn in the wavelength region 0.4-5.1 micrometers since its insertion into Saturn orbit in late 2004. We have detected the spectral signature of the C-H stretching molecular mode of aromatic and aliphatic hydrocarbons in the low albedo material covering parts of several of Saturn's satellites, notably Iapetus and Phoebe (Cruikshank et al. 2008). The distribution of this material is complex, and in the case of Iapetus we are seeking to determine if it is related to the native grey-colored materials left as lag deposits upon evaporation of the ices, or represents in-fall from an external source, notably the newly discovered large dust ring originating at Phoebe. This report covers our latest exploration of the nature and source of this organic material.

  10. Dynamics and distribution of Jovian dust ejected from the Galilean satellites

    Science.gov (United States)

    Liu, Xiaodong; Sachse, Manuel; Spahn, Frank; Schmidt, Jürgen

    2016-07-01

    In this paper, the dynamical analysis of the Jovian dust originating from the four Galilean moons is presented. High-accuracy orbital integrations of dust particles are used to determine their dynamical evolution. A variety of forces are taken into account, including the Lorentz force, solar radiation pressure, Poynting-Robertson drag, solar gravity, the satellites' gravity, plasma drag, and gravitational effects due to nonsphericity of Jupiter. More than 20,000 dust particles from each source moon in the size range from 0.05 μm to 1 cm are simulated over 8000 (Earth) years until each dust grain hits a sink (moons, Jupiter, or escape from the system). Configurations of dust number density in the Jovicentric equatorial inertial frame are calculated and shown. In a Jovicentric frame rotating with the Sun the dust distributions are found to be asymmetric. For certain small particle sizes, the dust population is displaced towards the Sun, while for certain larger sizes, the dust population is displaced away from the Sun. The average lifetime as a function of particle size for ejecta from each source moon is derived, and two sharp jumps in the average lifetime are analyzed. Transport of dust between the Galilean moons and to Jupiter is investigated. Most of the orbits for dust particles from Galilean moons are prograde, while, surprisingly, a small fraction of orbits are found to become retrograde mainly due to solar radiation pressure and Lorentz force. The distribution of orbital elements is also analyzed.

  11. Evolution of solids in the Jovian subnebula: Implications for the formation of the Galilean satellites

    Science.gov (United States)

    Ronnet, T.; Mousis, O.; Vernazza, P.

    2016-12-01

    The four Galilean satellites are thought to have formed within an accretion disk surrounding Jupiter during the late stages of its formation. Here we investigate the fate of solids of different sizes in the accretion disk. The dynamics of the solids is followed along with their thermodynamic evolution. This allows us to track the water ice-to-rock mass fraction of the planetesimals as they sublimate and lose mass when heated in the disk. We then compare our results to the known bulk composition of the Jovian moons and draw some conclusions as regards their formation.

  12. Cassini Imaging of Auroral Emissions on the Galilean Satellites

    Science.gov (United States)

    Geissler, P.; McEwen, A.; Porco, C.

    2001-05-01

    Cassini captured several sequences of images showing Io, Europa and Ganymede while the moons were eclipsed by Jupiter. Io was the best studied of the satellites, with 4 eclipses successfully recorded. Earlier eclipse imaging by Galileo (Geissler et al., Science 295, 870-874) had shown colorful atmospheric emissions from Io and raised questions concerning their temporal variability and the identity of the emitting species. With its high data rate and numerous filter combinations, Cassini was able to fill some of the gaps in our knowledge of Io's visible aurorae. Io's bright equatorial glows were detected at previously unknown wavelengths and were also seen in motion. One eclipse took place on 12/29/2000 while Io was far from the plasma torus center. The pair of equatorial glows near the sub-Jupiter and anti-Jupiter points appeared about equal in brightness and changed little in location or intensity over a two hour period. Io crossed the plasma torus center during the next eclipse on 1/01/2001, as it passed through System III magnetic longitudes from 250 to 303 degrees. The equatorial glows were seen to shift in latitude during this eclipse, tracking the tangent points of the jovian magnetic field lines. This behaviour is similar to that observed for ultraviolet and other atomic emissions, and confirms that these visible glows are powered by Birkeland currents connecting Io and Jupiter. The eclipse on 1/05/2001 provided the best spectral measurements of the aurorae. The equatorial glows were detected at near ultraviolet wavelengths, consistent with their interpretation as molecular SO2 emissions. More than 100 kR were recorded in the ISS UV3 filter (300-380 nm) along with a similar intensity in BL1 (290-500 nm), comparable to Galileo estimates. At least 50 kR were detected in UV2 images (265-330 nm). No detection was made in UV1 (235-280 nm), allowing us to place an upper limit of about 100 kR. A new detection of the equatorial glows was made in the IR1 band (670

  13. Between ice and gas: CO2 on the icy satellites of Jupiter and Saturn

    Science.gov (United States)

    Hibbitts, C.

    2010-12-01

    CO2 exists in the surfaces of the icy Galilean and Saturnian satellites [1-6], yet despite its discovery over a decade ago on Ganymede, and five years ago on the Saturnian satellites, its nature is still debated [7]. On the Galilean satellites Callisto and Ganymede, the CO2 that is detected is bound to, or trapped within, the non-ice materials that prevent it from sublimating or otherwise escaping from the surface. On Europa, it resides within both the ice and nonice materials [8,9]. While greater abundances of CO2 may exist in the interiors of these moons, or small amounts may be continually created through particle bombardment of the surface, the observed CO2 is only a trace material, with a few hundred molecules responsible for the deepest absorption features and an estimated molar abundance of 0.1% [2; 10-12]. Yet its presence may provide essential clues to processes that shape the surfaces of the moon [13] and potentially key to understanding the composition of potential oceans in the subsurfaces. We continue measurements of the infrared properties associated with CO2 adsorbed onto nonice materials under pressures and at temperatures relevant to these icy satellites using bidirectional reflectance spectroscopy from ~ 1.5 to 5.5 μm. Previous measurements, using transmission spectroscopy, demonstrated both a compositional and a temperature dependence on the spectral signature of adsorbed CO2 [14]. Bidirectional spectroscopy enables detection of lower concentrations of adsorbate on fine-grained materials such as clays due to their large surface area to volume ratios and thus large surface areas that may be covered by adsorbate [15]. The effectiveness of transmission spectroscopy was also limited by the strong absorption of light within the pressed sample and its impermeability, which limited the coverage by adsorbate to the pellet’s outer surface. All measurements demonstrate that CO2 adsorbs onto montmorillonite clays, possibly due to its quadrupole moment

  14. Obliquity of the Galilean satellites: The influence of a global internal liquid layer

    CERN Document Server

    Baland, R -M; Van Hoolst, T

    2012-01-01

    The obliquity of the Galilean satellites is small but not yet observed. Studies of cycloidal lineaments and strike-slip fault patterns on Europa suggest that Europa's obliquity is about 1 deg, although theoretical models of the obliquity predict the obliquity to be one order of magnitude smaller for an entirely solid Europa. Here, we investigate the influence of a global liquid layer on the obliquity of the Galilean satellites. Io most likely has a fully liquid core, while Europa, Ganymede, and Callisto are thought to have an internal global liquid water ocean beneath an external ice shell. We use a model for the obliquity based on a Cassini state model extended to the presence of an internal liquid layer and the internal gravitational and pressure torques induced by the presence of this layer. We find that the obliquity of Io only weakly depends on the different internal structure models considered, because of the weak influence of the liquid core which is therefore almost impossible to detect through observ...

  15. 10 years of mapping the icy saturnian satellites

    Science.gov (United States)

    Roatsch, Thomas; Kersten, Elke; Matz, Klaus-Dieter; Porco, Carolyn

    2014-05-01

    The Cassini spacecraft started its tour through the Saturnian system in July 2004. The Imaging Science Subsystem onboard the orbiter con-sists of a high-resolution Narrow Angle Camera (NAC) with a focal length of 2000 mm and a Wide Angle Camera (WAC) with a focal length of 200 mm [1]. One of the main objectives of the Cassini mission is to investigate the icy Saturnian satellites. These satellites were imaged in many flybys during the no-minal mission between 2004 and 2008. The imaging campaign continued during the first extended mission (''Equinox mission'') between 2008 and 2010 and continues during the current second extended mission (''Solstice mission''). It is now possible to image also the Northern parts of the Icy satellites which were not illuminated during the nominal mission. Mosaicking: The image data processing chain con-sists of the same steps as described in [2]: radiometric calibration, geometric correction, map projection, and mosaicking. Spacecraft position and camera pointing data are available in the form of SPICE kernels (http://naif.jpl.nasa.gov). While the orbit information is sufficiently accurate to be used directly for mapping purposes, the pointing information must be corrected using limb fits (semi-controlled mosaics) or by photo-grammetric bundle adjustment (controlled mosaics). The coordinate system adopted by the Cassini mis-sion for satellite mapping is the IAU ''planetographic'' system, consisting of planetographic latitude and posi-tive West longitude. The surface position of the prime meridian as defined by the IAU cartography working group [3] is defined by small craters. New values for the rotational parameter W0 which defines the location of the prime meridian at January 1, 2000 were calcula-ted based on the high-resolution mosaics to be consis-tent with this definition [4] and approved by the IAU [3]. Cartographic maps: Three different quadrangle schemes were used for the generation of the maps and the atlases [5]: • A

  16. Remote Sensing of Icy Galilean Moon Surface and Atmospheric Composition Using Low Energy (1 eV-4 keV) Neutral Atom Imaging

    Science.gov (United States)

    Collier, M. R.; Sittler, E.; Chornay, D.; Cooper, J. F.; Coplan, M.; Johnson, R. E.

    2004-01-01

    We describe a low energy neutral atom imager suitable for composition measurements Europa and other icy Galilean moons in the Jovian magnetosphere. This instrument employs conversion surface technology and is sensitive to either neutrals converted to negative ions, neutrals converted to positive ions and the positive ions themselves depending on the power supply. On a mission such as the Jupiter Icy Moons Orbiter (JIMO), two back-to-back sensors would be flown with separate power supplies fitted to the neutral atom and iodneutral atom sides. This will allow both remote imaging of 1 eV atmospheres, and in situ measurements of ions at similar energies in the moon ionospheres and Jovian magnetospheric plasma. The instrument provides composition measurements of the neutrals and ions that enter the spectrometer with a mass resolution dependent on the time-of-flight subsystem and capable of resolving molecules. The lower energy neutrals, up to tens of eV, arise from atoms and molecules sputtered off the moon surfaces and out of the moon atmospheres by impacts of more energetic (keV to MeV) ions from the magnetosphere. Direct Simulation Monte Carlo (DSMC) models are used to convert measured neutral abundances to compositional distributions of primary and trace species in the sputtered surfaces and atmospheres. The escaping neutrals can also be detected as ions after photo- or plasma-ionization and pickup. Higher energy, keV neutrals come from charge exchange of magnetospheric ions in the moon atmospheres and provide information on atmospheric structure. At the jovicentric orbits of the icy moons the presence of toroidal gas clouds, as detected at Europa's orbit, provide M e r opportunities to analyze both the composition of neutrals and ions originating from the moon surfaces, and the characteristics of magnetospheric ions interacting with neutral cloud material. Charge exchange of low energy ions near the moons, and directional distributions of the resultant neutrals

  17. Icy Satellite Science Today and in Cassini's Final Three Years

    Science.gov (United States)

    Buratti, B. J.

    2014-12-01

    The Cassini Mission has turned our view of Saturn's icy moons from scientific sketches to fully realized worlds. Among the major discoveries are: Activity on Enceladus and associated plumes that originate in small hot spots on its south pole and that appear to be modulated by tidal forces; a liquid subsurface water ocean on Enceladus that is a habitable environment; several new moons; debris rings associated with moons; a unique equatorial ridge on Iapetus; the identity of new constituents on the moons including carbon dioxide ice on most of them and polycyclic aromatic hydrocarbons (PAHs)on Iapetus; differentiated or partially differentiated interiors; nano-iron on the surfaces of the moons and in the rings; volatile segregation on Iapetus and Hyperion; and a bewildering array of geologic processes on the small moons. But our new view of these icy worlds has spawned new questions. Among these unanswered questions are: How variable are the plumes? Have any other moons had activity similar to that on Enceladus and did it continue up to the recent past? How much dust do the moons contribute to the region around Saturn? What caused the ridge on Iapetus? What are the interiors of the moons like? How differentiated and compensated are they? Five additional targeted flybys, two of Dione and three of Enceladus, have been designed to answer these questions and will be implemented during the remainder of the Solstice Mission. The Dione flybys both include gravity passes to determine its state of differentiation. One of the flybys is optimized to measure the fields and particle environment around Dione. One of the two remote-sensing flybys of Enceladus will scrutinize the south polar region to further understand the size, temperature, and variability of the emitting areas, while the other will observe the north pole to determine why it is so different from the south. The third Enceladus flyby involves an unprecedented pass less than 50 km above the surface into the midst of

  18. Astrometry of mutual approximations between natural satellites. Application to the Galilean moons

    CERN Document Server

    Morgado, B; Vieira-Martins, R; Camargo, J I B; Dias-Oliveira, A; Gomes-Júnior, A R

    2016-01-01

    Typically we can deliver astrometric positions of natural satellites with errors in the 50-150 mas range. Apparent distances from mutual phenomena, have much smaller errors, less than 10 mas. However, this method can only be applied during the equinox of the planets. We developed a method that can provide accurate astrometric data for natural satellites -- the mutual approximations. The method can be applied when any two satellites pass close by each other in the apparent sky plane. The fundamental parameter is the central instant $t_0$ of the passage when the distances reach a minimum. We applied the method for the Galilean moons. All observations were made with a 0.6 m telescope with a narrow-band filter centred at 889 nm with width of 15 nm which attenuated Jupiter's scattered light. We obtained central instants for 14 mutual approximations observed in 2014-2015. We determined $t_0$ with an average precision of 3.42 mas (10.43 km). For comparison, we also applied the method for 5 occultations in the 2009 m...

  19. Astrometry of mutual approximations between natural satellites. Application to the Galilean moons

    Science.gov (United States)

    Morgado, B.; Assafin, M.; Vieira-Martins, R.; Camargo, J. I. B.; Dias-Oliveira, A.; Gomes-Júnior, A. R.

    2016-08-01

    Typically we can deliver astrometric positions of natural satellites with errors in the 50-150 mas range. Apparent distances from mutual phenomena, have much smaller errors, less than 10 mas. However, this method can only be applied during the equinox of the planets. We developed a method that can provide accurate astrometric data for natural satellites - the mutual approximations. The method can be applied when any two satellites pass close by each other in the apparent sky plane. The fundamental parameter is the central instant t0 of the passage when the distances reach a minimum. We applied the method for the Galilean moons. All observations were made with a 0.6 m telescope with a narrow-band filter centred at 889 nm with width of 15 nm which attenuated Jupiter's scattered light. We obtained central instants for 14 mutual approximations observed in 2014-2015. We determined t0 with an average precision of 3.42 mas (10.43 km). For comparison, we also applied the method for 5 occultations in the 2009 mutual phenomena campaign and for 22 occultations in the 2014-2015 campaign. The comparisons of t0 determined by our method with the results from mutual phenomena show an agreement by less than 1σ error in t0, typically less than 10 mas. This new method is particularly suitable for observations by small telescopes.

  20. Modeling Spectra of Icy Satellites and Cometary Icy Particles Using Multi-Sphere T-Matrix Code

    Science.gov (United States)

    Kolokolova, Ludmilla; Mackowski, Daniel; Pitman, Karly M.; Joseph, Emily C. S.; Buratti, Bonnie J.; Protopapa, Silvia; Kelley, Michael S.

    2016-10-01

    The Multi-Sphere T-matrix code (MSTM) allows rigorous computations of characteristics of the light scattered by a cluster of spherical particles. It was introduced to the scientific community in 1996 (Mackowski & Mishchenko, 1996, JOSA A, 13, 2266). Later it was put online and became one of the most popular codes to study photopolarimetric properties of aggregated particles. Later versions of this code, especially its parallelized version MSTM3 (Mackowski & Mishchenko, 2011, JQSRT, 112, 2182), were used to compute angular and wavelength dependence of the intensity and polarization of light scattered by aggregates of up to 4000 constituent particles (Kolokolova & Mackowski, 2012, JQSRT, 113, 2567). The version MSTM4 considers large thick slabs of spheres (Mackowski, 2014, Proc. of the Workshop ``Scattering by aggregates``, Bremen, Germany, March 2014, Th. Wriedt & Yu. Eremin, Eds., 6) and is significantly different from the earlier versions. It adopts a Discrete Fourier Convolution, implemented using a Fast Fourier Transform, for evaluation of the exciting field. MSTM4 is able to treat dozens of thousands of spheres and is about 100 times faster than the MSTM3 code. This allows us not only to compute the light scattering properties of a large number of electromagnetically interacting constituent particles, but also to perform multi-wavelength and multi-angular computations using computer resources with rather reasonable CPU and computer memory. We used MSTM4 to model near-infrared spectra of icy satellites of Saturn (Rhea, Dione, and Tethys data from Cassini VIMS), and of icy particles observed in the coma of comet 103P/Hartley 2 (data from EPOXI/DI HRII). Results of our modeling show that in the case of icy satellites the best fit to the observed spectra is provided by regolith made of spheres of radius ~1 micron with a porosity in the range 85% - 95%, which slightly varies for the different satellites. Fitting the spectra of the cometary icy particles requires icy

  1. Cryovolcanic Conduit Evolution and Eruption on Icy Satellites

    Science.gov (United States)

    Mitchell, K. L.

    2014-12-01

    In silicate volcanism, such as on Earth or Io, eruptions typically result from fracture formation caused by interaction of tectonic stresses with inflating, pressurized magma sources, leading to transport of melt through an evolving conduit. On icy satellites the paradigm may be similar, resulting from some combination of tidal stresses and expansion of freezing water within, or near the base of, an ice shell. Such a fracture will result in eruption if mass continuity can be established, with buoyancy aided by exsolution and expansion of dissolved volatiles. After onset, conduit shape evolves due to: (1) shear-stresses or frictional erosional; (2) wallrock "bursting" due to massive wall stresses; (3) wall melting or condensation of particles due to heat transfer; or (4) changes in applied stresses. Preliminary thermodynamic and fluid mechanical analysis suggests some initial cooling during ascent resulting from exsolution and expansion of volatiles, thermally buffered by freezing, Conduit contraction may occur, and so evolution towards a deep, gas-filled plume chamber is difficult to accommodate without evoking a co-incidental process. Conduit flaring occurs near the surface where velocities are greatest, enhancing erosion. Here, viscous dissipative heating exceeds adiabatic cooling, and so some boiling (a few wt%) may occur. In contrast with silicate volcanism, decompression to below the triple point will occur within conduit, vent or jet, resulting in rapid freezing and boiling of the remaining water at a 6.8:1 ratio. Subsequent isentropic or adiabatic expansion within erupting jets may result in a few percent net of condensation or sublimation. These effects combined lead to ~4:1-7:1 solid:vapor ratios in the jet for most eruption conditions. These figures are consistent with the ~6:1 inferred in Enceladus' jets, supporting the hypothesis that the Enceladus plume draws from a subsurface body of liquids through a conduit. Similar results are anticipated if

  2. Geodesy and cartography methods of exploration of the outer planetary systems: Galilean satellites and Enceladus

    Science.gov (United States)

    Zubarev, Anatoliy; Kozlova, Natalia; Kokhanov, Alexander; Oberst, Jürgen; Nadezhdina, Irina; Patraty, Vyacheslav; Karachevtseva, Irina

    Introduction. While Galilean satellites have been observed by different spacecrafts, including Pioneer, Voyager-1 and -2, Galileo, New Horizons, and Enceladus by Cassini and Voyager-2, only data from Galileo, Cassini and the two Voyagers are useful for precise mapping [1, 2]. For purposes of future missions to the system of outer planets we have re-computed the control point network of the Io, Ganymede and Enceladus to support spacecraft navigation and coordinate knowledge. Based on the control networks, we have produced global image mosaics and maps. Geodesy approach. For future mission Laplace-P we mainly focused on Ganymede which coverage is nearly complete except for polar areas (which includes multispectral data). However, large differences exist in data resolutions (minimum global resolution: 30 km/pixel). Only few areas enjoy coverage by highest resolution images, so we suggest to obtain regional Digital Elevation Models (DEMs) from stereo images for selected areas. Also using our special software, we provide calculation of illumination conditions of Ganymede surface in various representations [3]. Finally, we propose a careful evaluation of all available data from the previous Voyager and Galileo missions to re-determine geodetic control and rotation model for other Galilean satellites - Callisto and Europe. Mapping. Based on re-calculated control point networks and global mosaics we have prepared new maps for Io, Ganymede and Enceladus [4]. Due to the difference in resolution between the images, which were also taken from different angles relative to the surface, we can prepare only regional high resolution shape models, so for demonstrating of topography and mapping of the satellites we used orthographic projection with different parameters. Our maps, which include roughness calculations based on our GIS technologies [5], will also be an important tool for studies of surface morphology. Conclusions. Updated data collection, including new calculation of

  3. A. A. Michelson's Jovian Galilean-Satellite Interferometer at Lick Observatory in 1891

    Science.gov (United States)

    Osterbrock, D. E.

    2004-12-01

    Albert A. Michelson, America's first Nobel laureate in physics, measured the angular diameter of the red supergiant star Betelgeuse in 1920 with Francis G. Pease, using the 100-inch Mount Wilson reflector as the basis of his stellar interferometer. But he had first published the concept in 1890 and tested it on celestial objects with a telescope at Lick Observatory in 1891. He used its 12-inch refractor to measure the angular diameters of the four Galilean satellites of Jupiter, assisted at the telescope by W. W. Campbell, then a young astronomer who had just joined the Lick staff. Edward S. Holden, the Lick director, had invited Michelson to come to Mount Hamilton and use its telescopes as a guest observer. Michelson had first tried and proved his method on artificial circular disks in his laboratory at Clark University, Worcester, Mass., using a 2-inch "glass." Then in 1889 and 1890 he hoped to test it at Harvard College Observatory, but apparently the telescope or the atmospheric conditions did not work out. At Lick he did achieve success, and his measured angular diameters were nearer to the true values we know from close-up space measurements of today than those of any of the top visual observers of the time. Correspondence in the Lick Archives shows that Michelson intended to come back there to use its big 36-inch refractor to improve the measurements, but he never did so. Selections from Michelson's published papers and photographs of him, the telescope, and the instrument will be posted.

  4. N-body Simulations of Satellite Formation around Giant Planets: Origin of Orbital Configuration of the Galilean Moons

    CERN Document Server

    Ogihara, Masahiro

    2012-01-01

    As the number of discovered extrasolar planets has been increasing, diversity of planetary systems requires studies of new formation scenarios. It is important to study satellite formation in circumplanetary disks, which is often viewed as analogous to formation of rocky planets in protoplanetary disks. We investigated satellite formation from satellitesimals around giant planets through N-body simulations that include gravitational interactions with a circumplanetary gas disk. Our main aim is to reproduce the observable properties of the Galilean satellites around Jupiter through numerical simulations, as previous N-body simulations have not explained the origin of the resonant configuration. We performed accretion simulations based on the work of Sasaki et al. (2010), in which an inner cavity is added to the model of Canup & Ward (2002, 2006). We found that several satellites are formed and captured in mutual mean motion resonances outside the disk inner edge and are stable after rapid disk gas dissipat...

  5. Astrobiological and Geological Implications of Convective Transport in Icy Outer Planet Satellites

    Science.gov (United States)

    Pappalardo, Robert T.; Zhong, Shi-Jie; Barr, Amy

    2005-01-01

    The oceans of large icy outer planet satellites are prime targets in the search for extraterrestrial life in our solar system. The goal of our project has been to develop models of ice convection in order to understand convection as an astrobiologically relevant transport mechanism within icy satellites, especially Europa. These models provide valuable constraints on modes of surface deformation and thus the implications of satellite surface geology for astrobiology, and for planetary protection. Over the term of this project, significant progress has been made in three areas: (1) the initiation of convection in large icy satellites, which we find probably requires tidal heating; (2) the relationship of surface features on Europa to internal ice convection, including the likely role of low-melting-temperature impurities; and (3) the effectiveness of convection as an agent of icy satellite surface-ocean material exchange, which seems most plausible if tidal heating, compositional buoyancy, and solid-state convection work in combination. Descriptions of associated publications include: 3 published papers (including contributions to 1 review chapter), 1 manuscript in revision, 1 manuscript in preparation (currently being completed under separate funding), and 1 published popular article. A myriad of conference abstracts have also been published, and only those from the past year are listed.

  6. Jupiter Icy Moons Explorer (JUICE): Science Objectives, Mission and Instruments (abstract)

    NARCIS (Netherlands)

    Gurvits, L.; Plaut, J.J.; Barabash, S.; Bruzzone, L.; Dougherty, M.; Erd, C.; Fletcher, L.; Gladstone, R.; Grasset, O.; Hartogh, P.; Hussmann, H.; Iess, L.; Jaumann, R.; Langevin, Y.; Palumbo, P.; Piccioni, G...; Titov, D.; Wahlund, J.E.

    2014-01-01

    The JUpiter ICy Moons Explorer (JUICE) is a European Space Agency mission that will fly by and observe the Galilean satellites Europa, Ganymede and Callisto, characterize the Jovian system in a lengthy Jupiter-orbit phase, and ultimately orbit Ganymede for in-depth studies of habitability, evolution

  7. X-ray Probes of Magnetospheric Interactions with Jupiter's Auroral zones, the Galilean Satellites, and the Io Plasma Torus

    Science.gov (United States)

    Elsner, R. F.; Ramsey, B. D.; Waite, J. H., Jr.; Rehak, P.; Johnson, R. E.; Cooper, J. F.; Swartz, D. A.

    2004-01-01

    Remote observations with the Chandra X-ray Observatory and the XMM-Newton Observatory have shown that the Jovian system is a source of x-rays with a rich and complicated structure. The planet's polar auroral zones and its disk are powerful sources of x-ray emission. Chandra observations revealed x-ray emission from the Io Plasma Torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from these moons is certainly due to bombardment of their surfaces of highly energetic protons, oxygen and sulfur ions from the region near the Torus exciting atoms in their surfaces and leading to fluorescent x-ray emission lines. Although the x-ray emission from the Galilean moons is faint when observed fiom Earth orbit, an imaging x-ray spectrometer in orbit around these moons, operating at 200 eV and above with 150 eV energy resolution, would provide a detailed mapping (down to 40 m spatial resolution) of the elemental composition in their surfaces. Here we describe the physical processes leading to x-ray emission fiom the surfaces of Jupiter's moons and the instrumental properties, as well as energetic ion flux models or measurements, required to map the elemental composition of their surfaces. We discuss the proposed scenarios leading to possible surface compositions. For Europa, the two most extreme are (1) a patina produced by exogenic processes such as meteoroid bombardment and ion implantation, and (2) upwelling of material fiom the subsurface ocean. We also describe the characteristics of X - m , an imaging x-ray spectrometer under going a feasibility study for the JIM0 mission, with the ultimate goal of providing unprecedented x-ray studies of the elemental composition of the surfaces of Jupiter's icy moons and Io, as well as of Jupiter's auroral x-ray emission.

  8. A 1-D evolutionary model for icy satellites, applied to Enceladus

    CERN Document Server

    Prialnik, Uri Malamud Dina

    2015-01-01

    We develop a long-term 1-D evolution model for icy satellites that couples multiple processes: water migration and differentiation, geochemical reactions and silicate phase transitions, compaction by self-gravity, and ablation. The model further considers the following energy sources and sinks: tidal heating, radiogenic heating, geochemical energy released by serpentinization or absorbed by mineral dehydration, gravitational energy and insolation, and heat transport by conduction, convection, and advection. We apply the model to Enceladus, by guessing the initial conditions that would render a structure compatible with present-day observations, assuming the initial structure to have been homogeneous. Assuming the satellite has been losing water continually along its evolution, we postulate that it was formed as a more massive, more icy and more porous satellite, and gradually transformed into its present day state due to sustained long-term tidal heating. We consider several initial compositions and evolution...

  9. Mass-radius relationships in icy satellites after Voyager

    Science.gov (United States)

    Lupo, M. J.

    1982-01-01

    Using improved data for the masses and radii of the satellites of Jupiter and Saturn, models accounting for self-compression effects are presented for the interiors of Europa, Ganymede, Callisto, Rhea, and Titan. For the differentiated models, two different possible scenarios for heat transport are treated, as well as two different compositions for the silicate component. Undifferentiated models are also treated. In each case, the models of Ganymede, Callisto, and Titan show noticeable similarities. It is found that estimates of the ice-rock ratio are dependent upon the assumptions made about the heat transport mechanisms, the rock composition, and on the distribution of rock and ice in the satellite's interior.

  10. Origin of the Different Architectures of the Jovian and Saturnian Satellite Systems

    OpenAIRE

    Sasaki, Takanori; Stewart, Glen R.; Ida, Shigeru

    2010-01-01

    The Jovian regular satellite system mainly consists of four Galilean satellites that have similar masses and are trapped in mutual mean motion resonances except for the outer satellite, Callisto. On the other hand, the Saturnian regular satellite system has only one big icy body, Titan, and a population of much smaller icy moons. We have investigated the origin of these major differences between the Jovian and Saturnian satellite systems by semi-analytically simulating the growth and orbital ...

  11. The rheology and composition of cryovolcanic flows on icy satellites

    Science.gov (United States)

    Kargel, Jeffrey S.

    1993-01-01

    The rheologic properties of terrestrial lavas have been related to morphologic features of their flows, such as levees, banked surfaces, multilobate structures, and compressible folds. These features also have been used to determine rheologies and constrain the compositions of extraterrestrial flows. However, with rare exceptions, such features are not resolvable in Voyager images of the satellites of outer planets. Often only flow length and edge thickness of cryovolcanic flows can be measured reasonably accurately from Voyager images. The semiempirical lava-flow model presented here is a renewed effort to extract useful information from such measurements.

  12. VIS-NIR Spectrophotometric Study of the Saturnian icy Satellites by Cassini-VIMS

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Tosi, F.; Coradini, A.; Cerroni, P.; Adriani, A.; McCord, T. B.; Baines, K. H.; Bellucci, G.; Brown, R. H.; Bibring, J.; Buratti, B. J.; Clark, R. N.; Combes, M.; Cruikshank, D. P.; Formisano, V.; Jaumann, R.; Langevin, Y. G.; Matson, D. L.; Mennella, V.; Nelson, R. M.; Nicholson, P. D.; Sicardy, B.; Sotin, C.

    2007-12-01

    After the first three years of the nominal mission aboard the Cassini probe the VIMS (Visual and Infrared Mapping Spectrometer) experiment has collected more than one thousand useful full-disk observations of both regular (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus, Phoebe) and minor (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso) icy moons of Saturn. These data, acquired from a variety of distances and inclinations from the equatorial plane, with different phase angles and hemispheric coverage, are analyzed by using several spectroscopic indicators (I/F continuum level, slopes, bands strengths) in order to identify analogies and differences in the compositional units of satellites and derive the phase curves at different longitudes; many observations acquired close to zero phase angle allow us to measure the opposition surge effect on several satellites. Concerning the composition we have derived the distribution of the water ice abundance and grain size from the almost pure icy surfaces of Enceladus and Calypso to the organic rich Hyperion, Iapetus and Phoebe. We report about the differences observed in the CO2 band position which is shifted at shorter wavelengths on Hyperion respect to Phoebe and Iapetus; this effect is probably related to a different distribution of clathrates on these icy surfaces. This research was completed thanks to the support of the Italian Space Agency (ASI).

  13. Distinct Aqueous and Hydrocarbon Cryovolcanism on Titan and Other Icy Satellites (Invited)

    Science.gov (United States)

    Kargel, J. S.; Furfaro, R.; Candelaria, P.

    2010-12-01

    Almost as soon as low-temperature solar nebula condensation sequences were first computed, it was realized that icy satellites have an internal heat source in long-lived radioactivities and could undergo differentiation; furthermore, freezing-point depressants, such as ammonia, and apolar gases, such as methane, could enable icy satellites to undergo aqueous cryovolcanism. The subsequent recognition of tidal and gravitational potential energy sources increased expectations for cryovolcanism. Voyager imaging and discovery of apparent cryovolcanic landforms—best exhibited by Triton, more ambiguous elsewhere-- motivated studies of the phase relations, phase densities and other thermodynamic properties, solid- and liquid-state rheologies, and possible cryovolcanic eruptive behaviors and landform characteristics. Ironically, the closer we examined Jovian icy moons with Galileo, the rarer cryovolcanic landforms appeared to be, with only a few compelling and very well characterized cases found mainly on Europa. Compelling examples of effusive cryovolcanism mainly occupied local topographic lows, whereas cases not in low spots tended to exhibit signs of explosive emplacement. Spectacular evidence of explosive cryovolcanism or geyser-like behavior was found by Cassini on Enceladus, but most other icy Saturnian moons did not reveal any compelling indicators of eruptions. Titan has so far been a mixed case, where some indicators of cryovolcanism have been reported, but there is scant compelling evidence for the process. We think that the sparseness of compelling effusive cryovolcanic features on icy satellites is because free, unreacted ammonia is less common than previously thought, and the main aqueous liquids are salt-water solutions denser than ice I; hence, they tend not to erupt, or they erupt only if driven by gas exsolution; even then, a thin ice shell and high heat flow is needed to allow aqueous liquids near enough to the surface to erupt. On satellites with thick

  14. Europa Jupiter System Mission (EJSM): Exploration Of The Jovian System And Its Icy Satellites

    Science.gov (United States)

    Grasset, Olivier; Pappalardo, R.; Greeley, R.; Blanc, M.; Dougherty, M.; Bunce, E.; Lebreton, J.; Prockter, L.; Senske, D.; EJSM Joint Science Definition Team

    2009-09-01

    The Europa Jupiter System Mission (EJSM) would be an international mission with the overall theme of investigating the emergence of habitable worlds around gas giants. Its goals are to (1) Determine whether the Jupiter system harbors habitable worlds and (2) Characterize the processes that are operating within the Jupiter system. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with orbiters developed by NASA and ESA (future contributions by JAXA and Russia are also possible). The baseline EJSM architecture consists of two primary elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. EJSM would directly address themes concerning the origin and evolution of satellite systems and water-rich environments in icy satellites. The potential habitability of the ocean-bearing moons Europa and Ganymede would be investigated, by characterizing the geophysical, compositional, geological, and external processes that affect these icy worlds. EJSM would also investigate Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant planets and their satellites would be better known. Most important, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM architecture provides opportunities for coordinated synergistic observations by JEO and JGO of the Jupiter and Ganymede magnetospheres, the volcanoes and torus of Io, the atmosphere of Jupiter, and comparative planetology of icy satellites. Each spacecraft would conduct both synergistic dual-spacecraft investigations and "stand-alone” measurements.

  15. Phase behavior and thermodynamic modeling of ices - implications for the geophysics of icy satellites. (Invited)

    Science.gov (United States)

    Choukroun, M.

    2010-12-01

    Ground-based observations and space missions to the outer Solar System (Voyager, Galileo, Cassini-Huygens) have evidenced recent geologic activity on many satellites of the giant planets. The diversity in surface expression of these icy moons’ activity is striking: from a scarred and young surface on Europa,1 with hydrated salts that may originate from a liquid layer buried at depth,2 to the South Polar plumes of Enceladus,3 where water ice particles are expelled along with a myriad of more complex molecules,4 to Titan, largest satellite of Saturn, with a dense atmosphere and a hydrocarbon cycle similar to the hydrological cycle on Earth.5 Large icy moons, i.e. with a radius greater than 500 km, share two particularities: a high content in water (on the order of a 30-70% bulk composition), and an interior segregated between a water-dominated mantle and a silicate-dominated core. The many forms water may have beneath the surface (ice polymorphs, liquid, hydrated compounds) bear a crucial role in the detected or alleged activity, and in the potential for astrobiological relevance. Indeed, any endogenic activity can only be approached through geophysical modelling of the internal structure and the thermal evolution. Current internal structure models for the icy moonse.g.,6 rely mainly on the contribution of each internal layer to the moment of inertia, generating non-unique solutions due to the large variability in density of H2O-bearing phases. Thermal evolution models,e.g.,7 can help constrain further the internal structure and geophysical activity, by starting with a given initial composition and state and investigating the thickening of icy layers through time. However, such models require both observational datasets and a precise description, as a function of pressure, temperature, and composition, of the thermophysical properties of the individual layers. Over the past century, experimental studies have provided a comprehensive view of the phase diagram of

  16. Saturn's icy satellites investigated by Cassini - VIMS. IV. Daytime temperature maps

    CERN Document Server

    Filacchione, Gianrico; Capaccioni, Fabrizio; Clark, Roger N; Cruikshank, Dale P; Ciarniello, Mauro; Cerroni, Priscilla; Bellucci, Giancarlo; Brown, Robert H; Buratti, Bonnie J; Nicholson, Phillip D; Jaumann, Ralf; McCord, Thomas B; Sotin, Christophe; Stephan, Katrin; Ore, Cristina M Dalle

    2016-01-01

    The spectral position of the 3.6 micron continuum peak measured on Cassini-VIMS I/F spectra is used as a marker to infer the temperature of the regolith particles covering the surfaces of Saturn's icy satellites. This feature is characterizing the crystalline water ice spectrum which is the dominant compositional endmember of the satellites' surfaces. Laboratory measurements indicate that the position of the 3.6 micron peak of pure water ice is temperature-dependent, shifting towards shorter wavelengths when the sample is cooled, from about 3.65 micron at T=123 K to about 3.55 micron at T=88 K. A similar method was already applied to VIMS Saturn's rings mosaics to retrieve ring particles temperature (Filacchione et al., 2014). We report here about the daytime temperature variations observed on the icy satellites as derived from three different VIMS observation types. Temperature maps are built by mining the complete VIMS dataset collected in years 2004-2009 (pre-equinox) and in 2009-2012 (post equinox) by sel...

  17. The fate of solid particles in the Jovian circumplanetary disk : Implications for the formation of the Galilean satellites

    Science.gov (United States)

    Ronnet, Thomas; Mousis, Olivier; Vernazza, Pierre

    2016-10-01

    The Galilean satellites are thought to have formed within an accretion disk surrounding Jupiter at the late stages of its formation. However, the structure of the gaseous disk, as well as the size and origin of the solids that eventually formed the satellites are yet to be constrained.Here we model an evolving gaseous disk around Jupiter and investigate the fate of solid particles of different sizes submitted to aerodynamic drag, turbulent diffusion, and heated by the surrounding gas. The motion of the solid particles is integrated in the (r-z) plane, taking into account dust settling and radial drift. The evolution of their ice-to-rock ratio is tracked when they cross the snowline and start to sublimate. Sublimation is coupled to the equations of motion as it changes the radius of the particle and consequently acts on the drag force. The I/R ratio then serves as a comparison to the observed bulk compositions of Io and Europa.

  18. A comparative study of Saturn's icy satellites spectrophotometric properties by Cassini/VIMS

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Coradini, A.; Cerroni, P.; Tosi, F.; McCord, T. B.; Baines, K. H.; Bellucci, G.; Brown, R. H.; Bibring, J. P.; Vims Team

    The main spectral properties of Saturn s icy satellites are investigated through the hyperspectral data collected by VIMS Visual and Infrared Mapping Spectrometer in the VIS-NIR range 0 35-5 1 micron from July 2004 to nowadays In this work we make a comparative analysis of more than 500 full-disk spectra obtained at different phase angles and leading-trailing coverage for 14 satellites Mimas Enceladus Tethys Dione Rhea Hyperion Iapetus Janus Epimetheus Telesto Calypso Atlas Prometheus Pandora The amount of contaminants organics and tholins on the surfaces is estimated thanks to the visible spectral slopes abundance of water ice and particle sizes are retrieved through the 1 5 2 0 and 3 0 micron absorption band strengths We present here also preliminary phase curves and mean full-disk spectra This work is supported by an ASI Italian Space Agency grant

  19. A semi-analytical model for exploring Galilean satellites formation from a massive disk

    CERN Document Server

    Miguel, Yamila

    2015-01-01

    A better knowledge of Jovian satellites' origins will bring light on the environment that surrounded Jupiter during its formation and can help us to understand the characteristics of this unique satellite system. We developed a semi-analytical model to investigate Jupiter's regular satellite formation and present the results of our population synthesis calculations. We performed simulations adopting a massive, static, low-viscosity circumplanetary disk model, in agreement with a current study of magnetorotational instability in a circum-planetary disk. We find that the high gas density leads to very rapid migration of satellitesimals due to gas drag and type II migration of satellites in a faster disk-dominated mode. A large concentration of solids, large building blocks and longer type II migration time-scales favor formation and survival of large satellites. However, bodies as massive as Ganymede and those located far away from Jupiter, such as Callisto, are difficult to form with this scenario.

  20. Origin, Bulk Chemical Composition and Physical Structure of the Galilean Satellites of Jupiter: A Post-Galileo Analysis

    Science.gov (United States)

    Prentice, A. J. R.

    1999-01-01

    The origin of Jupiter and the Galilean satellite system is examined in the light of the new data that has been obtained by the NASA Galileo Project. In particular, special attention is given to a theory of satellite origin which was put forward at the start of the Galileo Mission and on the basis of which several predictions have now been proven successful. These predictions concern the chemical composition of Jupiter's atmosphere and the physical structure of the satellites. According to the proposed theory of satellite origin, each of the Galilean satellites formed by chemical condensation and gravitational accumulation of solid grains within a concentric family of orbiting gas rings. These rings were cast off equatorially by the rotating proto-Jovian cloud (PJC which contracted gravitationally to form Jupiter some 4 1/2 billion years ago. The PJC formed from the gas and grains left over from the gas ring that had been shed at Jupiter's orbit by the contracting proto-solar cloud (PSC Supersonic turbulent convection provides the means for shedding discrete gas rings. The temperatures T (sub n) of the system of gas rings shed by the PSC and PJC vary with their respective mean orbital radii R (sub n) (n = 0, 1,2,...) according as T (sub n) proportional to R (sub n) (exp -0.9). If the planet Mercury condenses at 1640 K, so accounting for the high density of that planet via a process of chemical fractionation between iron and silicates, then T (sub n) at Jupiter's orbit is 158 K. Only 35% of the water vapour condenses out. Thus fractionation between rock and ice, together with an enhancement in the abundance of solids relative to gas which takes place through gravitational sedimentation of solids onto the mean orbit of the gas ring, ensures nearly equal proportions of rock and ice in each of Ganymede and Callisto. Io and Europa condense above the H20 ice point and consist solely of hydrated rock (h-rock). The Ganymedan condensate consists of h-rock and H20 ice. For

  1. Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A new technique to investigate Jovian upper atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tsumura, K. [Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Arimatsu, K.; Matsuura, S.; Shirahata, M.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronoutical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Egami, E. [Department of Astronomy, Arizona University, Tucson, AZ 85721 (United States); Hayano, Y.; Minowa, Y. [Hawaii Observatory, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Honda, C. [Research Center for Advanced Information Science and Technology, Aizu Research Cluster for Space Science, The University of Aizu, Aizu-Wakamatsu, Fukushima 965-8589 (Japan); Kimura, J. [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Kuramoto, K.; Takahashi, Y. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Nakajima, K. [Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Nakamoto, T. [Department of Earth and Planetary Sciences, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Surace, J., E-mail: tsumura@astr.tohoku.ac.jp [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-07-10

    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10{sup –6}-10{sup –7} of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

  2. JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system

    OpenAIRE

    Grasset, O.; Dougherty, K; Coustenis, A.; Bunce, J; Erd, C.; Titov, D.; Blanc, M.; Coates, A; Drossart, P.; Fletcher, N; Hussmann, H.; Jaumann, R.; N. Krupp; Lebreton, P; O. Prieto-Ballesteros

    2013-01-01

    Past exploration of Jupiter's diverse satellite system has forever changed our understanding of the unique environments to be found around gas giants, both in our solar system and beyond. The detailed investigation of three of Jupiter's Galilean satellites (Ganymede, Europa, and Callisto), which are believed to harbour subsurface water oceans, is central to elucidating the conditions for habitability of icy worlds in planetary systems in general. The study of the Jupiter system and the possib...

  3. Saturn's icy satellites investigated by Cassini-VIMS. II. Results at the end of nominal mission

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Clark, R.N.; Cuzzi, J.N.; Cruikshank, D.P.; Coradini, A.; Cerroni, P.; Nicholson, P.D.; McCord, T.B.; Brown, R.H.; Buratti, B.J.; Tosi, F.; Nelson, R.M.; Jaumann, R.; Stephan, K.

    2010-01-01

    We report the detailed analysis of the spectrophotometric properties of Saturn's icy satellites as derived by full-disk observations obtained by visual and infrared mapping spectrometer (VIMS) experiment aboard Cassini. In this paper, we have extended the coverage until the end of the Cassini's nominal mission (June 1st 2008), while a previous paper (Filacchione, G., and 28 colleagues [2007]. Icarus 186, 259-290, hereby referred to as Paper I) reported the preliminary results of this study. During the four years of nominal mission, VIMS has observed the entire population of Saturn's icy satellites allowing us to make a comparative analysis of the VIS-NIR spectral properties of the major satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus) and irregular moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso, Phoebe). The results we discuss here are derived from the entire dataset available at June 2008 which consists of 1417 full-disk observations acquired from a variety of distances and inclinations from the equatorial plane, with different phase angles and hemispheric coverage. The most important spectrophotometric indicators (as defined in Paper I: I/F continua at 0.55 ??m, 1.822 ??m and 3.547 ??m, visible spectral slopes, water and carbon dioxide bands depths and positions) are calculated for each observation in order to investigate the disk-integrated composition of the satellites, the distribution of water ice respect to "contaminants" abundances and typical regolith grain properties. These quantities vary from the almost pure water ice surfaces of Enceladus and Calypso to the organic and carbon dioxide rich Hyperion, Iapetus and Phoebe. Janus visible colors are intermediate between these two classes having a slightly positive spectral slope. These results could help to decipher the origins and evolutionary history of the minor moons of the Saturn's system. We introduce a polar representation of the spectrophotometric

  4. The Other Chemistry of the Jovian Icy Satellites - Low Energy and Sulfurous

    Science.gov (United States)

    Hudson, Reggie L.; Loeffler, M. J.; Moore, M. H.

    2010-01-01

    Spectra of Jupiter's icy satellites reveal surfaces dominated by H2O-ice with minor amounts of SO2 and other materials. The co-existence of H2O and SO2 in surfaces exposed to jovian magnetospheric radiation suggests that sulfuric acid (H2SO4) also could be present. This was noted by Carlson et al. (1999), who supported this suggestion with assignments of near-IR bands in Europa spectra to hydrated H2SO4. Laboratory experiments since have demonstrated radiolytically-driven syntheses in S- and SO2-containing H2O-Ices (Carlson et al., 2002; Moore et al., 2006). In the Cosmic Ice Laboratory, we recently have investigated the thermal chemistry of SO2 trapped in H2O-ice. IR spectra of H2O + SO2 mixtures recorded at 10 to 230 K were used to follow low-temperature reactions in the absence of radiation effects. No SO2 reactions were found at 10 K, but warming to more-relevant Europa temperatures produced both HSO3(-) and S2O5(2-). Added NH3 shifted the product composition toward SO3(2-) and away from the other ions. We find that H2O and SO2 react to produce sulfur oxyanions, such as bisulfite, that as much as 30% of the SO2 can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at and below the surfaces of the icy satellites in the jovian system.

  5. Mutual Phenomena between Galilean Satellites: PHEMU09 Campaign in Italy. (Italian Title: Occultazioni ed eclissi tra i satelliti medicei: i risultati della campagna PHEMU09 in Italia)

    Science.gov (United States)

    Marino, G.; Arena, C.; Barbieri, L.; Lopresti, C.; Lo Savio, E.; Marchini, A.; Masi, G.; Maulella, R.; Napoli, C.; Salvaggio, F.; Sbarufatti, G.; Sciuto, C.; Ruocco, N.; Ruisi, R.; Sofia, A.; Tontodonati, E.; Zambelli, R.

    2011-06-01

    Results of photometry of mutual phenomena between Galilean satellites are presented. The observations were performed in Italy during the international campaign PHEMU09.Relevant deviations (O-C) with respect to the expected central instants are present for many events. Taking into account the relative satellites’ longitudinal velocity, longitudinal discrepancies in km (and arcsec) are also computed. The discrepancies with respect to the expected flux drops during the occultations are apparently uncorrelated with the O-C on timing (and longitudinal deviations in km); moreover, for eclipses they seem greater than for occultations

  6. Analysis of mutual events of Galilean satellites observed from VBO during 2014-2015

    Science.gov (United States)

    Vasundhara, R.; Selvakumar, G.; Anbazhagan, P.

    2017-06-01

    Results of analysis of 23 events of the 2014-2015 mutual event series from the Vainu Bappu Observatory are presented. Our intensity distribution model for the eclipsed/occulted satellite is based on the criterion that it simulates a rotational light curve that matches the ground-based light curve. Dichotomy in the scattering characteristics of the leading and trailing sides explains the basic shape of the rotational light curves of Europa, Ganymede and Callisto. In the case of Io, the albedo map (courtesy United States Geological Survey) along with global values of scattering parameters works well. Mean values of residuals in (O - C) along and perpendicular to the track are found to be -3.3 and -3.4 mas, respectively, compared to 'L2' theory for the seven 2E1/2O1 events. The corresponding rms values are 8.7 and 7.8 mas, respectively. For the five 1E3/1O3 events, the along and perpendicular to the track mean residuals are 5.6 and 3.2 mas, respectively. The corresponding rms residuals are 6.8 and 10.5 mas, respectively. We compare the results using the chosen model (Model 1) with a uniform but limb-darkened disc (Model 2). The residuals with Model 2 of the 2E1/2O1 and 1E3/1O3 events indicate a bias along the satellite track. The extent and direction of bias are consistent with the shift of the light centre from the geometric centre. Results using Model 1, which intrinsically takes into account the intensity distribution, show no such bias.

  7. A Common Origin for Ridge-and-Trough Terrain on Icy Satellites by Sluggish Lid Convection

    CERN Document Server

    Barr, Amy C

    2014-01-01

    Ridge and trough terrain is a common landform on icy satellites of the outer solar system. Examples include the grooved terrain on Ganymede, gray bands on Europa, coronae on Uranus's moon Miranda, and ridges and troughs in the northern plains of Saturn's small, but active, moon Enceladus. Regardless of setting, the heat flow and strain rates associated with the formation of each of these terrains are similar: heat flows of order tens to a hundred milliwatts per meter squared, and deformation rates of order $10^{-16}$ to $10^{-12}$ s$^{-1}$. Barr (2008) and Hammond & Barr (2014a) have previously shown that the conditions associated with the formation of ridge and trough terrain on Ganymede and the south polar terrain on Enceladus are consistent with solid-state ice shell convection in a shell with a weak surface. Here, we show that sluggish lid convection can simultaneously create the heat flow and deformation appropriate for the formation of ridge and trough terrains on a number of satellites. This conclu...

  8. Precision Navigation of Cassini Images Using Rings, Icy Satellites, and Fuzzy Bodies

    Science.gov (United States)

    French, Robert S.; Showalter, Mark R.; Gordon, Mitchell K.

    2016-10-01

    Before images from the Cassini spacecraft can be analyzed, errors in the published pointing information (up to ~110 pixels for the Imaging Science Subsystem Narrow Angle Camera) must be corrected so that the line of sight vector for each pixel is known. This complicated and labor-intensive process involves matching the image contents with known features such as stars, rings, or moons. Metadata, such as lighting geometry or ring radius and longitude, must be computed for each pixel as well. Both steps require mastering the SPICE toolkit, a highly capable piece of software with a steep learning curve. Only after these steps are completed can the actual scientific investigation begin.We have embarked on a three-year project to perform these steps for all 400,000+ Cassini ISS images as well as images taken by the VIMS, UVIS, and CIRS instruments. The result will be a series of SPICE kernels that include accurate pointing information and a series of backplanes that include precomputed metadata for each pixel. All data will be made public through the PDS Ring-Moon Systems Node (http://www.pds-rings.seti.org). We expect this project to dramatically decrease the time required for scientists to analyze Cassini data.In a previous poster (French et al. 2014, DPS #46, 422.01) we discussed our progress navigating images using stars, simple ring models, and well-defined icy bodies. In this poster we will report on our current progress including the use of more sophisticated ring models, navigation of "fuzzy" bodies such as Titan and Saturn, and use of crater matching on high-resolution images of the icy satellites.

  9. Crater Relaxation and Stereo Imaging of the Icy Satellites of Jupiter and Saturn

    Science.gov (United States)

    Phillips, C. B.; Beyer, R. A.; Nimmo, F.; Roberts, J. H.; Robuchon, G.

    2010-12-01

    Crater relaxation has been used as a probe of subsurface temperature structure for over thirty years, both on terrestrial bodies and icy satellites. We are developing and testing two independent methods for processing stereo pairs to produce digital elevation models, to address how crater relaxation depends on crater diameter, geographic location, and stratigraphic position on the icy satellites of Jupiter and Saturn. Our topographic profiles will then serve as input into two numerical models, one viscous and one viscoelastic, to allow us to probe the subsurface thermal profiles and relaxation histories of these satellites. We are constructing stereo topography from Galileo and Cassini image pairs using the NASA Ames Stereo Pipeline (Moratto et al. 2010), an automated stereogrammetry tool designed for processing planetary imagery captured from orbiting and landed robotic explorers on other planets. We will also be using the commercial program SOCET SET from BAE Systems (Miller and Walker 1993; 1995). Qualitatively, it is clear that there are large spatial variations in the degree of crater relaxation among Jupiter’s and Saturn’s satellites. However, our use of stereo topography will allow quantitative measures of crater relaxation (e.g. depth:diameter ratio or equivalent) to be derived. Such measures are essential to derive quantitative estimates of the heat fluxes responsible for this relaxation. Estimating how surface heat flux has varied with time provides critical constraints on satellite thermal (and orbital) evolution. Craters undergo viscous relaxation over time at a rate that depends on the temperature gradient and crater scale. We are investigating how the near-surface satellite heat flux varied in time and space, based on our crater relaxation observations. Once we have crater profiles from our DEMs, we use them as input to two theoretical approaches: a relatively simple (viscous) numerical model in which time-varying heat fluxes can be included, and

  10. Ion processing of ices and the origin of SO2 and O3 on the icy surfaces of the icy jovian satellites

    Science.gov (United States)

    Boduch, P.; Brunetto, R.; Ding, J. J.; Domaracka, A.; Kaňuchová, Z.; Palumbo, M. E.; Rothard, H.; Strazzulla, G.

    2016-10-01

    We present new experimental results relative to 144 keV S9+ or Ar9+ ion implantation in targets made of oxygen rich frozen gases (O2, CO2) and mixtures with water ice. Spectra in the UV (200-400 nm) range have been obtained before and after implantation. The targets have been selected because they can be representative of the parent molecules from which SO2 and O3, observed to be present on the surfaces of Jupiter's icy Moons, could be formed due to radiolysis induced by the abundant magnetospheric ions. The results indicate that sulfur dioxide is not detectable after sulfur implantation in oxygen bearing species. Ozone is formed after argon and sulfur ion implantation. Sulfur implantation in O2 and CO2 targets also induces the formation of a band centered at about 255 nm (that we tentatively attribute to SO3- radicals). In the mixtures with water the band appears initially at the same wavelength and shifts to about 247 nm at higher ion fluences possibly indicating the formation of sulfite (HSO3-) ions. An absorption band observed on Ganymede is well fitted by using three components: ozone, sulfite ions and a not identified component having an absorption band centered at 298 nm. In all of the studied cases ion implantation produces a spectral reddening over the investigated spectral range (200-400 nm) that well mimics the observed spectral slopes of Jupiter's icy satellites.

  11. The response of subsurface oceans in icy satellites to tidally driven forcing

    Science.gov (United States)

    Chen, E. M.; Glatzmaier, G. A.; Nimmo, F.

    2009-12-01

    Observations from the Galileo and Cassini spacecraft suggest that subsurface global water oceans are likely present on multiple icy satellites of Jupiter and Saturn. However, the dynamics of these oceans, under the influence of a time-varying tidal potential and buoyancy and coriolis forces, have not been investigated in detail. We have investigated the large scale ocean flow in two ways. First, we simulate the 3-D global circulation of the subsurface oceans on Europa and Titan driven primarily by a time-varying tidal potential and secondarily by heating at the base of the ocean. Second, we analyze the behavior of tidally-forced subsurface oceans in two-dimensions using quasi-nonlinear shallow water theory. These approaches allow us to predict potentially observable effects, in particular non-synchronous rotation of the ice shell driven by ocean torques and spatial variations in the heat flow supplied to the base of the ice shell, and magnetic induction effects due to the ocean circulation. Time-series analyses suggest that the ocean responds primarily at the tidal frequency; however, there are responses at lower frequencies as well. Preliminary results of full 3-D simulations will be presented, and comparisons will be made to the forced shallow water model.

  12. Nonhydrostatic Effects and the Determination of Icy Satellites' Moment of Inertia

    CERN Document Server

    Gao, Peter

    2013-01-01

    We compare the moment of inertia (MOI) of a simple hydrostatic, two layer body as determined by the Radau-Darwin Approximation (RDA) to its exact hydrostatic MOI calculated to first order in the parameter q = w^2R^3/GM, where w, R, and M are the spin angular velocity, radius, and mass of the body, and G is the gravitational constant. RDA is in error by less than 1% for many configurations of core sizes and layer densities congruent with those of solid bodies in the Solar System. We determine the error in the MOI of icy satellites calculated with the RDA due to nonhydrostatic effects by using a simple model in which the core and outer shell have slight degree 2 distortions away from their expected hydrostatic shapes. Since the hydrostatic shape has an associated stress of order pw^2R^2 (where p is density) it follows that the importance of nonhydrostatic effects scales with the dimensionless number s/pw^2R^2, where s is the nonhydrostatic stress. This highlights the likely importance of this error for slowly r...

  13. Thermally-Induced Chemistry and the Jovian Icy Satellites: A Laboratory Study of the Formation of Sulfur Oxyanions

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2011-01-01

    Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Here we present new results on thermally-induced reactions at 50-100 K in solid H2O-SO2 mixtures, reactions that take place without the need for a high-radiation environment. We find that H2O and SO2 react to produce sulfur Oxyanions, such as bisulfite, that as much as 30% of the SO2 can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at temperatures relevant to the icy satellites in the Jovian system.

  14. The Results of Observations of Mutual Phenomena of the Galilean Satellites of Jupiter in 2009 and 2015 IN Nikolaev Astronomical Observatory

    Science.gov (United States)

    Pomazan, A.; Maigurova, N.; Kryuchkovskiy, V.

    The Earth and Jupiter once in 6 years have simultaneous passage of the ecliptic plane due to their orbital movement around the Sun. This makes it possible to observe the mutual occultations and eclipses in the Galilean satellites of Jupiter. We took part in the observational campaigns of the mutual phenomena in 2009 and 2014-15. The observations were made with a B/W CCD camera WAT-902H at the telescope MCT (D = 0.115 m, F = 2.0 m) of the Nikolaev Astronomical Observatory. The light curves of mutual phenomena in the satellites of Jupiter were obtained as a result of processing photometric observations. The exact moments of maximum phases and the amplitudes of the light variation have been determined from the analysis of the light curves. The data sets for the light curves have been sent in the IMCCE (Institute de Mecanique et de calcul des ephemerides, France) that coordinates the PHEMU campaigns.

  15. A Comparative Analysis of the Far Infrared Spectra of Saturn's Rings and Icy Satellites with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, Linda; Edgington, Scott G.

    2016-10-01

    We will report on a campaign to observe Saturn's main rings and major icy satellites with the Composite Infrared Spectrometer onboard Cassini. CIRS' three infrared detectors cover a combined spectral range of 10 to 1400 cm-1 (1 mm down to 7 microns). We focus on data from Focal Plane 1, which covers the 10 to 600 cm-1 range (1 mm to 16 microns). The apodized spectral resolution of the instrument can be varied from 15 cm-1 to 0.5 cm-1 (Flasar et al. 2004).The spectral behavior of Saturn's main rings and icy satellites in the far infrared has been the subject of previous studies with CIRS FP1 data (Spilker at al. 2005, Carvano et al. 2007, Morishima et al. 2012). These studies have shown that the infrared spectra of these icy rings and bodies are remarkably flat between about 40 to 200 microns. Longward of this, CIRS observations, as well as older spacecraft data, show a gradual decrease in ring emissivity. This roll-off in emissivity may be due to varying optical constants of water ice, which dominates the rings' composition, as one moves towards microwave wavelengths. Carvano et al. (2007), who analyzed spectra of the icy satellites Phoebe, Iapetus, Enceladus, Tethys and Hyperion, investigated the absence of emissivity features in spectra of those satellites. This absence is intriguing, as water ice, which dominates their surface composition, contains absorption features in the FP1 spectral range. They conclude that high porosity in these satellites' regoliths may explain this lack of spectral variability.To better characterize the far infrared spectra of the rings and satellites, we have implemented a series of dedicated observations. The goal is to obtain thousands of infrared spectra at 3 cm-1 resolution of each individual ring region and as many satellites as possible. We will have more spectra than Spilker et al. had for their work at a higher spectral resolution than in the analyses of Carvano et al. and Morishima et al. A preliminary analysis of these

  16. Overview of Cassini radio science at Saturn, Titan, and the icy satellites

    Science.gov (United States)

    Kliore, A. J.; Ambrosini, R.; Armstrong, J. W.; Flasar, F. M.; French, R. G.; Iess, L.; Marouf, E. A..; Nagy, A. F.; Rappaport, N. J.; Tortora, P.; Jpl/Dsn Radio Science Support Team

    The Cassini spacecraft which has been in orbit about Saturn for over two years is the first Radio Science platform to provide three downlink frequencies In addition to the X-band telemetry link 3 56 cm w l two other frequencies S-band 13 04 cm and Ka-band 0 94 cm are available This plus the high SNR 50 dBHz at X-band afforded by the 4 m diameter s c high gain antenna in combination with the excellent low noise receivers of the DSN as well as overall system stabilities of 1 part in 10 13 when referenced to the on-board ultra-stable oscillator USO in one-way operation and 1 part inx 10 15 for a two-way link make Cassini an unprecedented instrument of radio science The orbital tour phase of the mission has the following main radio science objectives a determination of the masses and gravity fields of Saturn s icy satellites Titan and Saturn through two-way tracking during fly-bys To date the masses of Phoebe Iapetus Dione Enceladus Rhea and Titan have been measured and will be reported here b Measurement of the structure and other properties of Saturn s rings through three-band occultation Seven near-diametric occultations at a high ring opening angle have been completed and the results will be presented here c Measurement of the vertical structure of the atmosphere and ionosphere of Saturn The same series of occultations have provided nearly equatorial observations of the atmosphere structure and the ionosphere and the results will be described here d Measurement of the vertical structure of

  17. Titan's Impact Cratering Record: Erosion of Ganymedean (and other) Craters on a Wet Icy Landscape

    Science.gov (United States)

    Schenk, P.; Moore, J.; Howard, A.

    2012-04-01

    We examine the cratering record of Titan from the perspective of icy satellites undergoing persistent landscape erosion. First we evaluate whether Ganymede (and Callisto) or the smaller low-gravity neighboring icy satellites of Saturn are the proper reference standard for evaluating Titan’s impact crater morphologies, using topographic and morphometric measurements (Schenk, 2002; Schenk et al. (2004) and unpublished data). The special case of Titan’s largest crater, Minrva, is addressed through analysis of large impact basins such as Gilgamesh, Lofn, Odysseus and Turgis. Second, we employ a sophisticated landscape evolution and modification model developed for study of martian and other planetary landforms (e.g., Howard, 2007). This technique applies mass redistribution principles due to erosion by impact, fluvial and hydrological processes to a planetary landscape. The primary advantage of our technique is the possession of a limited but crucial body of areal digital elevation models (DEMs) of Ganymede (and Callisto) impact craters as well as global DEM mapping of Saturn’s midsize icy satellites, in combination with the ability to simulate rainfall and redeposition of granular material to determine whether Ganymede craters can be eroded to resemble Titan craters and the degree of erosion required. References: Howard, A. D., “Simulating the development of martian highland landscapes through the interaction of impact cratering, fluvial erosion, and variable hydrologic forcing”, Geomorphology, 91, 332-363, 2007. Schenk, P. "Thickness constraints on the icy shells of the galilean satellites from impact crater shapes". Nature, 417, 419-421, 2002. Schenk, P.M., et al. "Ages and interiors: the cratering record of the Galilean satellites". In: Jupiter: The Planet, Satellites, and Magnetosphere, Cambridge University Press, Cambridge, UK, pp. 427-456, 2004.

  18. The effect of viscosity on impact cratering and possible application to the icy satellites of Saturn and Jupiter

    Science.gov (United States)

    Fink, J.; Gault, D.; Greeley, R.

    1984-01-01

    Impact experiments in Newtonian fluids with a range of viscosities of 0.001 to 60 Pa s demonstrate that transient crater volume and shape depend on target viscosity as well as on gravity. Volume is reduced, and depth-to-diameter ratio is increased for cratering events in which viscosity plays a dominant role. In addition to being affected by target kinematic viscosity, viscous scaling is most strongly influenced by projectile diameter, less strongly by projectile velocity, and least strongly by gravity. In a planetary context, viscous effects can occur for craters formed by small or slow moving impacting bodies, low planetary surface densities, high surface viscosities, and low gravity values; conditions all likely for certain impacts into the icy satellites of Saturn and Jupiter, especially if liquid mantles were still present beneath solid crusts. Age dating based on crater counts and size-frequency distributions for these icy bodies may have to be modified to account for the possibility that viscosity-dominated craters were initially smaller and deeper than their gravity-controlled counterparts.

  19. Saturn’s icy satellites investigated by Cassini-VIMS. II. Results at the end of nominal mission

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Clark, R. N.; Cuzzi, J. N.; Cruikshank, D. P.; Coradini, A.; Cerroni, P.; Nicholson, P. D.; McCord, T. B.; Brown, R. H.; Buratti, B. J.; Tosi, F.; Nelson, R. M.; Jaumann, R.; Stephan, K.

    2010-04-01

    We report the detailed analysis of the spectrophotometric properties of Saturn's icy satellites as derived by full-disk observations obtained by visual and infrared mapping spectrometer (VIMS) experiment aboard Cassini. In this paper, we have extended the coverage until the end of the Cassini's nominal mission (June 1st 2008), while a previous paper ( Filacchione, G., and 28 colleagues [2007]. Icarus 186, 259-290, hereby referred to as Paper I) reported the preliminary results of this study. During the four years of nominal mission, VIMS has observed the entire population of Saturn's icy satellites allowing us to make a comparative analysis of the VIS-NIR spectral properties of the major satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus) and irregular moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso, Phoebe). The results we discuss here are derived from the entire dataset available at June 2008 which consists of 1417 full-disk observations acquired from a variety of distances and inclinations from the equatorial plane, with different phase angles and hemispheric coverage. The most important spectrophotometric indicators (as defined in Paper I: I/ F continua at 0.55 μm, 1.822 μm and 3.547 μm, visible spectral slopes, water and carbon dioxide bands depths and positions) are calculated for each observation in order to investigate the disk-integrated composition of the satellites, the distribution of water ice respect to "contaminants" abundances and typical regolith grain properties. These quantities vary from the almost pure water ice surfaces of Enceladus and Calypso to the organic and carbon dioxide rich Hyperion, Iapetus and Phoebe. Janus visible colors are intermediate between these two classes having a slightly positive spectral slope. These results could help to decipher the origins and evolutionary history of the minor moons of the Saturn's system. We introduce a polar representation of the spectrophotometric

  20. Experimental investigation and planetary implications of the stability of clathrate hydrates in aqueous solution at icy satellite conditions

    Science.gov (United States)

    Dunham, M.; Choukroun, M.; Barmatz, M.; Hodyss, R. P.; Smythe, W. D.

    2012-12-01

    Clathrate hydrates consist of hydrogen-bonded water molecules forming cages in which gas molecules are trapped individually. They are among the favored volatile reservoirs in solar system bodies, and are expected to play an important role in many processes: accretion of volatiles in planetesimals, outgassing on Titan, Enceladus, and comets. Their insulating thermal properties and high mechanical strength also bear important implications for understanding the evolution of icy satellites like Europa. However, the conditions allowing for their formation and/or their dissociation and the release of volatiles to the atmosphere (Titan) or the plumes (Enceladus) are still poorly understood. This is mainly because of a lack of knowledge on the stability of mixed clathrate hydrates in presence of anti-freeze agents such as ammonia. We have developed a high-pressure cryogenic calorimeter to address this deficiency in the literature. This liquid nitrogen - cooled Setaram BT2.15 calorimeter is located at the JPL Ice Physics Laboratory. The temperature range achievable with this instrument is 77-473 K. This calorimeter uses Calvet elements (3D arrays of thermocouples) to measure the heat flow required to follow a predefined heating rate within a sample and a reference cell with a resolution of 0.1 μW. A gas handling system has been designed and fabricated in house to reach pressures up to 100 bars, corresponding to several km depth in icy satellites. The thermodynamic properties of CO2 and CH4 clathrates with ammonia are under investigation, and the results will be used to constrain a statistical thermodynamic model of clathrates for applications to planetary environments. Preliminary results will be shown at the meeting. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Support from the Minnesota Space Grant Consortium, the NASA Outer Planets Research program, and government sponsorship are gratefully

  1. The Radar for Icy Moon Exploration (RIME) on the JUICE Mission

    Science.gov (United States)

    Bruzzone, L.; Plaut, J.; Alberti, G.; Blankenship, D. D.; Bovolo, F.; Campbell, B. A.; Castelletti, D.; Gim, Y.; Ilisei, A. M.; Kofman, W. W.; Komatsu, G.; McKinnon, W. B.; Mitri, G.; Moussessian, A.; Notarnicola, C.; Orosei, R.; Patterson, G. W.; Pettinelli, E.; Plettemeier, D.

    2015-12-01

    The Radar for Icy Moon Exploration (RIME) is one of the main instruments included in the JUpiter ICy moons Explorer (JUICE) ESA mission. It is a radar sounder designed for studying the subsurface geology and geophysics of Galilean icy moons (i.e., Ganymede, Europa and Callisto) and for detecting possible subsurface water. RIME is designed for penetration of the icy moons up to a depth of 9 km. Two main operation scenarios are foreseen for RIME: i) flyby observations of Europa, Ganymede and Callisto (from a distance of 1000 km to the closest approach of about 400 km); and ii) circular orbital observations around Ganymede at 500 km of altitude. According to these scenarios, RIME is designed to explore the icy shell of the Galilean icy satellites by characterizing the wide range of compositional, thermal, and structural variation found in the subsurface of these moons. RIME observations will profile the ice shells of the Galilean icy satellites with specific focus on Ganymede given the circular orbital phase. The acquired measures will provide geological context on hemispheric (thousands of km), regional (hundreds of km with multiple overlaps), and targeted (tens of km) scales appropriate for a variety of hypothesis tests. RIME will operate in a single frequency band, centred at 9 MHz. The frequency was selected as the result of extensive study of penetration capabilities, surface roughness of the moons, Jovian radio noise, antenna accommodation, and system design. The 9 MHz frequency provides penetration capabilities and mitigation of surface scattering (which can cause signal loss and clutter issues), at the expense of mapping coverage, as it is likely to obtain high SNR observations only on the anti-Jovian side of the target moons. The RIME antenna is a 16 m dipole. The chirp pulse bandwidth is up to 3 MHz, which provides vertical resolution of about 50 m in ice after side lobe weighting. RIME will also operate with 1 MHz bandwidth to reduce data volume when

  2. Generalized Galilean Genesis

    CERN Document Server

    Nishi, Sakine

    2015-01-01

    The galilean genesis scenario is an alternative to inflation in which the universe starts expanding from Minkowski in the asymptotic past by violating the null energy condition stably. Several concrete models of galilean genesis have been constructed so far within the context of galileon-type scalar-field theories. We give a generic, unified description of the galilean genesis scenario in terms of the Horndeski theory, i.e., the most general scalar-tensor theory with second-order field equations. In doing so we generalize the previous models to have a new parameter (denoted by {\\alpha}) which results in controlling the evolution of the Hubble rate. The background dynamics is investigated to show that the generalized galilean genesis solution is an attractor, similarly to the original model. We also study the nature of primordial perturbations in the generalized galilean genesis scenario. In all the models described by our generalized genesis Lagrangian, amplification of tensor perturbations does not occur as ...

  3. SPH Simulations of Volatiles Loss from Icy Satellites During a Late Heavy Bombardment

    Science.gov (United States)

    Movshovitz, N.; Nimmo, F.; Korycansky, D.; Asphaug, E. I.; Owen, J. M.

    2013-12-01

    The present day ice-to-silicate ratio in satellites of the outer solar system can be used to constrain dynamical models of solar system formation [1]. The reason is that a period of intense impact activity after formation of the planets, implied by some dynamical models [2,3,4], could have resulted in significant mass loss, of ice preferentially, from these satellites. The location of Jovian and Saturnian satellites inside the gravity well of these giant planets implies high impact velocities, perhaps as high as 30 km/s [5]. Combined with small satellite masses, a Late Heavy Bombardment may well lead to a significant fraction of a satellite's mass ejected. In a previous study, Nimmo and Korycansky [1] calculate, using a scaling law for vaporization of ice from craters [6], the total expected ice loss from satellites of Jupiter, Saturn, and Uranus. They find that many satellites should have lost significant fractions (>10%) of their water ice. As many of these satellites do not appear to be significantly depleted in volatiles, this raises questions about the timing or intensity of a late heavy bombardment. (See also [4]). But this conclusion depends on some key assumptions regarding the distribution of impactor sizes and velocities, and, critically, the expected mass loss during a single impact. Here we compare predictions of impact-driven mass loss using direct hydrodynamical simulations of the relevant impact events, with the scaling law originally developed for cratering by small impactors [6]. The main advantage of this approach is that we can consider impacts between comparably sized bodies, where a cratering scaling law does not strictly apply. Another advantage of a direct hydro simulation is that we can track escaping mass, rather than vapor production. This is most significant for lower velocity impacts, typical of accretion [7,8]. This method should also be less sensitive to the choice of equation of state. To resolve preferential ice loss during impacts

  4. The long-period librations of large synchronous icy moons

    Science.gov (United States)

    Yseboodt, Marie; Van Hoolst, Tim

    2014-11-01

    A moon in synchronous rotation has longitudinal librations because of its non-spherical mass distribution and its elliptical orbit around the planet. We study the long-period librations of the Galilean satellites and Titan and include deformation effects and the existence of a subsurface ocean. We take into account the fact that the orbit is not keplerian and has other periodicities than the main period of orbital motion around Jupiter or Saturn due to perturbations by the Sun, other planets and moons. An orbital theory is used to compute the orbital perturbations due to these other bodies. For Titan we also take into account the large atmospheric torque at the semi-annual period of Saturn around the Sun.We numerically evaluate the amplitude and phase of the long-period librations for many interior structure models of the icy moons constrained by the mass, radius and gravity field.

  5. Icy satellites of Saturn: disk-integrated observations of the brightness opposition surge at low phase angles

    Science.gov (United States)

    Kulyk, I.; Jockers, K.

    2007-08-01

    The surfaces of most atmosphereless bodies exhibit two interesting optical phenomena at small phase angles, namely a strong brightness increase and negative values of the degree of linear polarization. Of particular interest is the appearance a nonlinear growth of the surface brightness and a second narrow minimum of polarization at phase angles less than 1-3°. These features of brightness and polarization in the narrow phase angle range near opposition are called the photometric and polarimetric opposition effects. These phenomena have attracted increased attention from the perspective of theories of light scattering in random media and their application to the determination of properties of the upper optically active regolith layers on the atmosphereless bodies. However, up to now photometric and especially polarimetric observations conducted at small phase angles are rare. In order to enlarge the amount of available observational data we have conducted photopolarimetric observations of the major icy Saturnian satellites. The observations were performed at the 2m-telescope of the Bulgarian National Observatory with the Two-Channel Focal Reducer of the Bulgarian Academy of Sciences built at the Max-Planck-Institute for Solar System Science. This instrument incorporates a two-channel imaging polarimeter which can be used in coronagraph setup. The light of Saturn and its rings is almost fully absorbed by a black glass and its diffraction pattern is eliminated by a Lyot stop. The photopolarimeter records intensity and degree of polarization of the satellites in two colors simultaneously. In this study, we present the first results of the disk-integrated photometry of Enceladus, Tethys, Dione, and Rhea in the red (center wavelength 694 nm, FWHM 79 nm) and near-infrared (center wavelength 888.5 nm, FWHM 29 nm, methane absorption band) spectral bands at phase angles between 5.6° and 0.01°. The resulting magnitudes can be represented as a sum of two terms, one

  6. Dust levitation as a major resurfacing process on the surface of a saturnian icy satellite, Atlas

    Science.gov (United States)

    Hirata, Naoyuki; Miyamoto, Hideaki

    2012-07-01

    A small inner satellite of Saturn, Atlas, has an enigmatic saucer-like shape explained by an accumulation of particles from A-ring of Saturn. However, its unusual smooth surface remains unexplained. Gardening through continuous particle impact events cannot be a unique explanation for the smoothness, because Prometheus does not exhibit a similar surface, though it too would have experienced a similar bombardment. Here, a detailed investigation using close-up images of Atlas reveals the surface to be (1) covered by fine particles (i.e., probably as small as several tens of micrometers); (2) mostly void of impact craters (i.e., only one has been thus far identified); and (3) continuously smooth, even between the equatorial ridge and the undulating polar region. These findings imply that some sort of crater-erasing process has been active on the surface of Atlas. From electro-static analyses, we propose that the upper-most layer of the fine particles can become electro-statically unstable and migrate as a result of dust levitation, which resulted in erasing craters on the surface of Atlas. If true, Atlas would represent the first recognized body where resurfacing is dominated by dust levitation.

  7. Generalized galilean genesis

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Sakine; Kobayashi, Tsutomu [Department of Physics, Rikkyo University, Toshima, Tokyo 175-8501 (Japan)

    2015-03-31

    The galilean genesis scenario is an alternative to inflation in which the universe starts expanding from Minkowski in the asymptotic past by violating the null energy condition stably. Several concrete models of galilean genesis have been constructed so far within the context of galileon-type scalar-field theories. We give a generic, unified description of the galilean genesis scenario in terms of the Horndeski theory, i.e., the most general scalar-tensor theory with second-order field equations. In doing so we generalize the previous models to have a new parameter (denoted by α) which results in controlling the evolution of the Hubble rate. The background dynamics is investigated to show that the generalized galilean genesis solution is an attractor, similarly to the original model. We also study the nature of primordial perturbations in the generalized galilean genesis scenario. In all the models described by our generalized genesis Lagrangian, amplification of tensor perturbations does not occur as opposed to what happens in quasi-de Sitter inflation. We show that the spectral index of curvature perturbations is determined solely from the parameter α and does not depend on the other details of the model. In contrast to the original model, a nearly scale-invariant spectrum of curvature perturbations is obtained for a specific choice of α.

  8. Forced-folding by laccolith and saucer-shaped sill intrusions on the Earth, planets and icy satellites

    Science.gov (United States)

    Michaut, Chloé

    2017-04-01

    Horizontal intrusions probably initially start as cracks, with negligible surface deformation. Once their horizontal extents become large enough compared to their depths, they make room for themselves by lifting up their overlying roofs, creating characteristic surface deformations that can be observed at the surface of planets. We present a model where magma flows below a thin elastic overlying layer characterized by a flexural wavelength Λ and study the dynamics and morphology of such a magmatic intrusion. Our results show that, depending on its size, the intrusion present different shapes and thickness-to-radius relationships. During a first phase, elastic bending of the overlying layer is the main source of driving pressure in the flow; the pressure decreases as the flow radius increases, the intrusion is bell-shaped and its thickness is close to being proportional to its radius. When the intrusion radius becomes larger than 4 times Λ, the flow enters a gravity current regime and progressively develops a pancake shape with a flat top. We study the effect of topography on flow spreading in particular in the case where the flow is constrained by a lithostatic barrier within a depression, such as an impact crater on planets or a caldera on Earth. We show that the resulting shape for the flow depends on the ratio between the flexural wavelength of the layer overlying the intrusion and the depression radius. The model is tested against terrestrial data and is shown to well explain the size and morphology of laccoliths and saucer-shaped sills on Earth. We use our results to detect and characterize shallow solidified magma reservoirs in the crust of terrestrial planets and potential shallow water reservoirs in the ice shell of icy satellites.

  9. Peptide synthesis triggered by comet impacts: A possible method for peptide delivery to the early Earth and icy satellites

    Science.gov (United States)

    Sugahara, Haruna; Mimura, Koichi

    2015-09-01

    We performed shock experiments simulating natural comet impacts in an attempt to examine the role that comet impacts play in peptide synthesis. In the present study, we selected a mixture of alanine (DL-alanine), water ice, and silicate (forsterite) to make a starting material for the experiments. The shock experiments were conducted under cryogenic conditions (77 K), and the shock pressure range achieved in the experiments was 4.8-25.8 GPa. The results show that alanine is oligomerized into peptides up to tripeptides due to the impact shock. The synthesized peptides were racemic, indicating that there was no enantioselective synthesis of peptides from racemic amino acids due to the impact shock. We also found that the yield of linear peptides was a magnitude higher than those of cyclic diketopiperazine. Furthermore, we estimated the amount of cometary-derived peptides to the early Earth based on two models (the Lunar Crating model and the Nice model) during the Late Heavy Bombardment (LHB) using our experimental data. The estimation based on the Lunar Crating model gave 3 × 109 mol of dialanine, 4 × 107 mol of trialanine, and 3 × 108 mol of alanine-diketopiperazine. Those based on the Nice model, in which the main impactor of LHB is comets, gave 6 × 1010 mol of dialanine, 1 × 109 mol of trialanine, and 8 × 109 mol of alanine-diketopiperazine. The estimated amounts were comparable to those originating from terrestrial sources (Cleaves, H.J., Aubrey, A.D., Bada, J.L. [2009]. Orig. Life Evol. Biosph. 39, 109-126). Our results indicate that comet impacts played an important role in chemical evolution as a supplier of linear peptides, which are important for further chemical evolution on the early Earth. Our study also highlights the importance of icy satellites, which were formed by comet accumulation, as prime targets for missions searching for extraterrestrial life.

  10. Subluminal Galilean Genesis

    CERN Document Server

    Creminelli, Paolo; Khoury, Justin; Nicolis, Alberto; Trincherini, Enrico

    2012-01-01

    We put forward an improved version of the Galilean Genesis model that addresses the problem of superluminality. We demote the full conformal group to Poincare symmetry plus dilations, supplemented with approximate galilean shift invariance in the UV and at small field values. In this way fluctuations around the NEC-violating cosmological background are made substantially subluminal, and superluminality cannot be reached by any small change of the solution, in contrast with the original model. Dilation invariance still protects the scale-invariance of correlation functions of a massless test scalar - which is the source of the observed cosmological fluctuations - but the explicit breaking of the conformal group can be potentially observed in higher-order correlators. We also highlight a subtlety in matching the NEC-violating phase with the standard cosmological evolution, and discuss the possible couplings of the Galileon to gravity.

  11. Galilean-Invariant XEFT

    CERN Document Server

    Braaten, Eric

    2015-01-01

    XEFT is a low-energy effective field theory for charm mesons and pions that provides a systematically improvable description of the X(3872) resonance. A Galilean-invariant formulation of XEFT is introduced to exploit the fact that mass is very nearly conserved in the transition D*0 --> D0 pi0. The transitions D*0 --> D0 pi0 and X --> D0 D0-bar pi0 are described explicitly in XEFT. The effects of the decay D*0 --> D0 gamma and of short-distance decay modes of the X(3872), such as J/psi --> pi+ pi-, can be taken into account by using complex on-shell renormalization schemes for the D*0 propagator and for the D*0 D0-bar propagator in which the positions of their complex poles are specified. Galilean-invariant XEFT is used to calculate the D*0 D0-bar scattering length to next-to-leading order. Galilean invariance ensures the cancellation of ultraviolet divergences without the need for truncating an expansion in powers of the ratio of the pion and charm meson masses.

  12. Galilean relativistic fluid mechanics

    Science.gov (United States)

    Ván, P.

    2017-01-01

    Single-component nonrelativistic dissipative fluids are treated independently of reference frames and flow-frames. First the basic fields and their balances are derived, then the related thermodynamic relations and the entropy production are calculated and the linear constitutive relations are given. The usual basic fields of mass, momentum, energy and their current densities, the heat flux, pressure tensor and diffusion flux are the time- and spacelike components of the third-order mass-momentum-energy density-flux four-tensor. The corresponding Galilean transformation rules of the physical quantities are derived. It is proved that the non-equilibrium thermodynamic frame theory, including the thermostatic Gibbs relation and extensivity condition and also the entropy production, is independent of the reference frame and also the flow-frame of the fluid. The continuity-Fourier-Navier-Stokes equations are obtained almost in the traditional form if the flow of the fluid is fixed to the temperature. This choice of the flow-frame is the thermo-flow. A simple consequence of the theory is that the relation between the total, kinetic and internal energies is a Galilean transformation rule.

  13. Teleparallel formalism of galilean gravity

    CERN Document Server

    Ulhoa, S C; Santana, A E

    2011-01-01

    A pseudo-Riemannian manifold is introduced, with light-cone coordinates in (4+1) dimensional space-time, to describe a Galilei covariant gravity. The notion of 5-bein and torsion are developed and a galilean version of teleparallelism is constructed in this manifold. The formalism is applied to two spherically symmetric configurations. The first one is an ansatz which is inferred by following the Schwarzschild solution in general relativity. The second one is a solution of galilean covariant equations. In addition, this Galilei teleparallel approach provides a prescription to couple the 5-bein field to the galilean covariant Dirac field.

  14. Arbitrary Spin Galilean Oscillator

    CERN Document Server

    Hagen, C R

    2014-01-01

    The so-called Dirac oscillator was proposed as a modification of the free Dirac equation which reproduces many of the properties of the simple harmonic oscillator but accompanied by a strong spin-orbit coupling term. It has yet to be extended successfully to the arbitrary spin S case primarily because of the unwieldiness of general spin Lorentz invariant wave equations. It is shown here using the formalism of totally symmetric multispinors that the Dirac oscillator can, however, be made to accommodate spin by incorporating it into the framework of Galilean relativity. This is done explicitly for spin zero and spin one as special cases of the arbitrary spin result. For the general case it is shown that the coefficient of the spin-orbit term has a 1/S behavior by techniques which are virtually identical to those employed in the derivation of the g-factor carried out over four decades ago.

  15. Galilean relativistic fluid mechanics

    CERN Document Server

    Ván, Péter

    2015-01-01

    Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...

  16. Logarithmic exotic conformal Galilean algebras

    Energy Technology Data Exchange (ETDEWEB)

    Henkel, Malte, E-mail: Malte.henkel@univ-lorraine.fr [Groupe de Physique Statistique, Institut Jean Lamour (CNRS UMR 7198), Université de Lorraine Nancy, B.P. 70239, F-54506 Vandoeuvre-lès-Nancy Cedex (France); Hosseiny, Ali, E-mail: al_hosseiny@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran 19839 (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Rouhani, Shahin, E-mail: rouhani@ipm.ir [Department of Physics, Sharif University of Technology, P.O. Box 11165-9161, Tehran (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2014-02-15

    Logarithmic representations of the conformal Galilean algebra (CGA) and the Exotic Conformal Galilean algebra (ECGA) are constructed. This can be achieved by non-decomposable representations of the scaling dimensions or the rapidity indices, specific to conformal Galilean algebras. Logarithmic representations of the non-exotic CGA lead to the expected constraints on scaling dimensions and rapidities and also on the logarithmic contributions in the co-variant two-point functions. On the other hand, the ECGA admits several distinct situations which are distinguished by different sets of constraints and distinct scaling forms of the two-point functions. Two distinct realisations for the spatial rotations are identified as well. This is the first concrete example of a reducible, but non-decomposable representation, without logarithmic terms. Such cases had been anticipated before.

  17. What is Eating Ozone? Thermal Reactions between SO2 and O3 and Implications for the Icy Satellites

    Science.gov (United States)

    Loeffler, Mark; Hudson, Reggie L.; Gerakines, Perry A.

    2016-10-01

    Here we present first results on a non-radiolytic, thermally-driven reaction sequence in solid H2O + SO2 + O3 mixtures at 50 – 130 K, which produces bisulfate (HSO4-). The results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making co-detection of these species unlikely. Our results also give a viable explanation for why O3 has not been detected on Callisto and why the concentration of SO2 appears to be highest in its leading hemisphere. Furthermore our results also predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. This work is supported by NASA's Outer Planets Research program.

  18. Galilean invariance in Lagrangian mechanics

    Science.gov (United States)

    Mohallem, J. R.

    2015-10-01

    The troublesome topic of Galilean invariance in Lagrangian mechanics is discussed in two situations: (i) A particular case involving a rheonomic constraint in uniform motion and (ii) the general translation of an entire system and the constants of motion involved. A widespread impropriety in most textbooks is corrected, concerning a condition for the equality h = E to hold.

  19. The rheology of icy satellites

    Science.gov (United States)

    Sammis, C. G.

    1984-01-01

    High-temperature creep in orthoenstatite under conditions of controlled oxygen fugacity was studied. It was found that creep was conttrolled by the extremely thin layer of SiO2 which wetted the grain boundaries. Slight reduction of the (Mg, Fe)SiO3 enstatite during hot pressing produced microscopic particles of Fe and the thin film of intergranular SiO2. This result highlights another complication in determining the flow properties of iron bearing silicates which constitute the bulk of terrestrial planets and moons. The Phenomenon may be important in the ductile formation of any extraterrestrial body which is formed in a reducing environment. The rheology of dirty ice was studied. This involves micromechanical modeling of hardening phenomena due to contamination by a cosmic distribution of silicate particles. The larger particles are modeled by suspension theory. In order to handle the distribution of particles sizes, the hardening is readed as a critical phenomenon, and real space renormalization group techniques are used. Smaller particles interact directly with the dislocations. The particulate hardening effect was studied in metals. The magnitude of such hardening in ice and the defect chemistry of ice are studied to assess the effects of chemical contamination by methane, ammonia, or other likely contaminants.

  20. Shear failure of icy satellites: Present-day implications along Enceladus's Tiger Stripes and indications of past strike-slip faulting on Ganymede's Dardanus Sulcus

    Science.gov (United States)

    Cameron, M. E.; Smith-Konter, B. R.; Pappalardo, R. T.

    2012-12-01

    The icy fractured surfaces of both Enceladus and Ganymede offer many candidate faults for studying both past and potentially present tectonic activity. Recent studies have suggested that Enceladus's "tiger stripe" fractures may be associated with tectonic strike-slip (shear) motions as a result of Coulomb failure, but low coefficients of friction were primarily considered in past stress models. Recent work suggests that friction is highly sensitive to the state of seismic fault slip; low friction (μf = 0.1-0.2) may be applicable in initial slip events and high friction (μf = 0.3-0.6) may be more appropriate for subsequent sliding velocities. On Ganymede, strike-slip tectonics is common, notably where a prominent fault offsets Dardanus Sulcus. We investigate the role of fault friction and orbital eccentricity in the development of Enceladus's tiger stripes and Ganymede's Dardanus Sulcus. We consider both tidal diurnal and non-synchronous rotation (NSR) stresses, as applicable, and compute Coulomb failure conditions for these target fractures. For the Enceladus tiger stripes, previous shear failure models showed that low coefficients of friction (μf = 0.1-0.2) and shallow fracture depths (2-4 km) provide a very active diurnal shear failure scenario. Our new simulations suggest that shear failure is also possible for friction coefficients as high as uf = 0.6 at depths of 2 km, but the lateral extent of failure is suppressed in comparison. For Ganymede's Dardanus Sulcus, we consider tidal stress scenarios for both present (0.0013) and possible past high (~0.05) eccentricity. We find that NSR shear stress resolved along the Dardanus fault is sufficient to induce failure to ~1.4 km depths for μf ~0.3. For past high eccentricity, diurnal stress would have modulated NSR stress by ~100 kPa through Ganymede's tidal cycle, which could have also induced shear heating and tidal walking mechanisms. Together, these tidally driven failure models for Enceladus and Ganymede are

  1. Galilean Geometry in Condensed Matter Systems

    CERN Document Server

    Geracie, Michael

    2016-01-01

    We present a systematic means to impose Galilean invariance within field theory. We begin by defining the most general background geometries consistent with Galilean invariance and then turn to applications within effective field theory, fluid dynamics, and the quantum Hall effect.

  2. Radio Science Concepts for Exploring the Interior Structures of Jupiter's Icy Moons

    Science.gov (United States)

    Asmar, S. W.; Anderson, J. D.; Castillo, J. C.; Folkner, W. M.; Konopliv, A. S.; Marouf, E. A.; Rappaport, N. J.; Schubert, G.; Spilker, T. R.; Tyler, G. L.; Watkins, M. M.; Yoder, C. F.

    2003-12-01

    A set of concepts are proposed for the Jupiter Icy Moons Orbiter (JIMO) to apply Radio Science tools to investigate the interior structures of the Galilean Satellites and address key questions on their thermal and dynamical evolution. Multi-frequency Doppler tracking and ranging of the orbiter can be used to measure the gravity harmonic coefficients of the satellites as well as their secular and dynamic potential Love numbers. These measurements will confirm the presence of a subsurface ocean and constrain the oceanic density. Under the assumption of hydrostatic equilibrium, the core's size and density will be determined. The potential tidal phase lag, a function of the viscosity profile, will be determined or limited for each body. Altimetry data produce local topography and topographic harmonic coefficients as well as the topographic Love number. Combining the gravity and topography data will determine the mean as well as the spatial variations of the crustal thickness and produce a model of the cryospheric structure. This knowledge leads to understanding the mechanisms of topographic support or compensation and any large-scale geomorphological features related to the interior. Accelerometers measure the non-gravitational forces acting on the spacecraft, a typical systematic noise type in the gravity data and, thus, improve the accuracy of the measurement. Gradiometers improve the resolution of the data by providing higher spatial resolution in the gravity field and its correlation with the topography. The resulting information will be crucial to establishing the link between surface and internal dynamics leading to identifying the terrain with easiest ocean access and to understanding the origin of the chaotic terrains and ridges. Time observations of surface features enable an examination of the difference between the obliquity and inclination which, when combined with the gravity data, provide a measurement of the moments of inertia. High stability coherent

  3. Impact-Generated Dust Clouds Surrounding the Galilean Moons

    CERN Document Server

    Krüger, H; Grün, E; Kr\\"uger, Harald~; Krivov, Alexander V.; Gr\\"un, Eberhard

    2003-01-01

    Tenuous dust clouds of Jupiter's Galilean moons Io, Europa, Ganymede and Callisto have been detected with the in-situ dust detector on board the Galileo spacecraft. The majority of the dust particles have been sensed at altitudes below five radii of these lunar-sized satellites. We identify the particles in the dust clouds surrounding the moons by their impact direction, impact velocity, and mass distribution. Average particle sizes are 0.5 to $\\rm 1 \\mu m$, just above the detector threshold, indicating a size distribution with decreasing numbers towards bigger particles. Our results imply that the particles have been kicked up by hypervelocity impacts of micrometeoroids onto the satellites' surfaces. The measured radial dust density profiles are consistent with predictions by dynamical modeling for satellite ejecta produced by interplanetary impactors (Krivov et al., PSS, 2003, 51, 251--269), assuming yield, mass and velocity distributions of the ejecta from laboratory measurements. The dust clouds of the th...

  4. Structure of The Planar Galilean Conformal Algebra

    Science.gov (United States)

    Gao, Shoulan; Liu, Dong; Pei, Yufeng

    2016-08-01

    In this paper, we compute the low-dimensional cohomology groups of the planar Galilean conformal algebra introduced by Bagchi and Goparkumar. Consequently we determine its derivations, central extensions, and automorphisms.

  5. Jupiter Icy Moons Explorer: mission status after the Definition Phase

    Science.gov (United States)

    Titov, Dmitri; Barabash, Stas; Bruzzone, Lorenzo; Dougherty, Michele; Erd, Christian; Fletcher, Leigh; Gare, Philippe; Gladstone, Randall; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Langevin, Yves; Palumbo, Pasquale; Piccioni, Giuseppe; Sarri, Giuseppe; Wahlund, Jan-Erik; Witasse, Olivier

    2015-04-01

    JUpiter ICy moons Explorer (JUICE), the ESA first large-class mission within the Cosmic Vision Program 2015-2025, was adopted in November 2014. The mission will perform detailed investigations of Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. The overarching theme for JUICE is: The emergence of habitable worlds around gas giants. At Ganymede, the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions will be elucidated. JUICE will study the moons' interactions with the magnetosphere, gravitational coupling and long-term tidal evolution of the Galilean satellites. JUICE highly capable scientific payload includes 10 state-of-the-art instruments onboard the spacecraft plus one experiment that uses the spacecraft telecommunication system with ground-based radio telescopes. The remote sensing package includes a high-resolution multi-band visible imager (JANUS) and spectro-imaging capabilities from the

  6. Dynamical modelling of the Galilean moons for the JUICE mission

    Science.gov (United States)

    Dirkx, D.; Lainey, V.; Gurvits, L. I.; Visser, P. N. A. M.

    2016-12-01

    Radio tracking and astrometric data obtained by the JUICE mission, using the PRIDE, 3GM and JANUS instruments, will allow the dynamics of the Galilean moons to be measured to unprecedented accuracy. As a result, the dynamical models used for creating ephemerides from these data will most likely require the inclusion of various heretofore neglected physical effects. To determine which effects will need to be included, we perform a sensitivity analysis of the influence on the dynamics of the system for a wide array of gravitational, tidal and rotational characteristics of the system. We estimate the dynamics of the Galilean moons with a given perturbation turned off, using ideal three-dimensional measurements of the satellites' positions generated with these perturbations turned on. In doing so, we assess the capabilities of the nominal dynamical model to absorb the influence of this perturbations. We analyze the dynamical behaviour over a period of five years, and limit our analysis to effects that may be observable from JUICE radio tracking and optical astrometry data. Our simulations comprise a short-period (5 years) sensitivity analysis of the dynamics of the moons, and not a simulation of the tracking data inversion for JUICE. Our analysis indicates that the nominal dynamical model of the Galilean satellites can very efficiently absorb the influence of the current uncertainties in most of the physical parameters of the Jovian system, to a level where these uncertainties will not be influential for JUICE-derived ephemerides. An important exception is the influence of tidal dissipation: the k2 / Q of Io will be clearly observable by JUICE tracking data, which will be strongly correlated with the weaker effect of Jupiter's k2 / Q . The dissipation inside Europa may also be weakly constrained by JUICE tracking data. Without improvements in the Jovian gravity field from the Juno mission, the estimation of Jupiter zonal gravity field coefficients at degrees 2, 3 and 5

  7. Seventh symposium on EBIS/T and their applications combined with a workshop on ion sources for hadron colliders, a satellite meeting to ICIS'97 (invited)

    Science.gov (United States)

    Becker, R.

    1998-02-01

    The 7th symposium on EBIS and EBIT and their applications has been organized by M. Kleinod and R. Becker in Gelnhausen, Germany the week before ICIS'97. It was combined with a workshop on ion sources for hadron colliders being reported on by J. Alessi. Former EBIS symposia which have taken place are: 1977 at GSI, Darmstadt, Germany; 1981 in Saclay and Orsay, France; 1985 at Cornell University, Ithaca, New York; 1988 at Brookhaven National Lab (BNL), Brookhaven, New York; 1991 at JINR, Dubna, Russia; and 1994 at MSI, Stockholm, Sweden. The next one will be organized in the year 2000 by Krsto Prelec, BNL and Martin Stöckli, Manhattan, Kansas.

  8. Impact-induced differentiation in icy bodies

    CERN Document Server

    Tonks, W Brian; Melosh, H Jay

    2016-01-01

    By the time icy objects grow to about the mass of Europa and silicate bodies grow to approximately lunar mass, a large high-speed impact can generate an intact melt region that allows the dense material to gravitationally segregate, forming a large density anomaly. If this anomaly generates sufficient differential stress, it rapidly segregates to the object's center, triggering whole body differentiation. We used an impact melting model based on the Hugoniot equations, the linear shock-particle velocity relationship, and the empirical relationship between shock pressure and distance coupled with a Monte Carlo simulation of the late accretion process to determine conditions under which large impacts trigger differentiation in icy bodies. In a gas-free environment, impacts of projectiles in the satellite's accretion zone have a small probability of triggering differentiation in surviving proto-satellites as small as Triton. The probability increases to 100% by the time surviving proto-satellites grow to the mas...

  9. Survivability of bacteria ejected from icy surfaces after hypervelocity impact.

    Science.gov (United States)

    Burchell, Mark J; Galloway, James A; Bunch, Alan W; Brandão, Pedro F B

    2003-02-01

    Both the Saturnian and Jovian systems contain satellites with icy surfaces. If life exists on any of these icy bodies (in putative subsurface oceans for example) then the possibility exists for transfer of life from icy body to icy body. This is an application of the idea of Panspermia, wherein life migrates naturally through space. A possible mechanism would be that life, here taken as bacteria, could become frozen in the icy surface of one body. If a high-speed impact occurred on that surface, ejecta containing the bacteria could be thrown into space. It could then migrate around the local region of space until it arrived at a second icy body in another high-speed impact. In this paper we consider some of the necessary steps for such a process to occur, concentrating on the ejection of ice bearing bacteria in the initial impact, and on what happens when bacteria laden projectiles hit an icy surface. Laboratory experiments using high-speed impacts with a light gas gun show that obtaining icy ejecta with viable bacterial loads is straightforward. In addition to demonstrating the viability of the bacteria carried on the ejecta, we have also measured the angular and size distribution of the ejecta produced in hypervelocity impacts on ice. We have however been unsuccessful at transferring viable bacteria to icy surfaces from bacteria laden projectiles impacting at hypervelocities.

  10. Galilean Anomalies and Their Effect on Hydrodynamics

    CERN Document Server

    Jain, Akash

    2015-01-01

    We extend the null background construction of [arXiv:1505.05677,arXiv:1509.04718] to include torsion and a conserved spin current, and use it to study gauge and gravitational anomalies in Galilean theories coupled to torsional Newton-Cartan backgrounds. We establish that the relativistic anomaly inflow mechanism with an appropriately modified anomaly polynomial, can be used to generate these anomalies. Similar to relativistic case, we find that Galilean anomalies also survive only in even dimensions. Further, these anomalies only effect the gauge and rotational symmetries of a Galilean theory; in particular the Milne boost symmetry remains non-anomalous. We also extend the transgression machinery used in relativistic fluids to fluids on null backgrounds, and use it to determine how these anomalies affect the constitutive relations of a Galilean fluid. Unrelated to Galilean fluids, we propose an analogue of the off-shell second law of thermodynamics for relativistic fluids introduced by [arXiv:1106.0277], to i...

  11. X-Ray Probes of Jupiter's Auroral Zones, Galilean Moons, and the Io Plasma Torus

    Science.gov (United States)

    Elsner, R. F.; Ramsey, B. D.; Swartz, D. A.; Rehak, P.; Waite, J. H., Jr.; Cooper, J. F.; Johnson, R. E.

    2005-01-01

    Remote observations from the Earth orbiting Chandra X-ray Observatory and the XMM-Newton Observatory have shown the the Jovian system is a rich and complex source of x-ray emission. The planet's auroral zones and its disk are powerful sources of x-ray emission, though with different origins. Chandra observations discovered x-ray emission from the Io plasma torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from the moons is due to bombardment of their surfaces by highly energetic magnetospheric protons, and oxygen and sulfur ions, producing fluorescent x-ray emission lines from the elements in their surfaces against an intense background continuum. Although very faint when observed from Earth orbit, an imaging x-ray spectrometer in orbit around the icy Galilean moons would provide a detail mapping of the elemental composition in their surfaces. Here we review the results of Chandra and XMM-Newton observations of the Jovian system and describe the characteristics of X-MIME, an imaging x-ray spectrometer undergoing study for possible application to future missions to Jupiter such as JIMO. X-MIME has the ultimate goal of providing detailed high-resolution maps of the elemental abundances of the surfaces of Jupiter's icy moons and Io, as well as detailed study of the x-ray mission from the Io plasma torus, Jupiter's auroral zones, and the planetary disk.

  12. The Gravity- Powered Calculator, a Galilean Exhibit

    Science.gov (United States)

    Cerreta, Pietro

    2014-04-01

    The Gravity-Powered Calculator is an exhibit of the Exploratorium in San Francisco. It is presented by its American creators as an amazing device that extracts the square roots of numbers, using only the force of gravity. But if you analyze his concept construction one can not help but recall the research of Galileo on falling bodies, the inclined plane and the projectile motion; exactly what the American creators did not put into prominence with their exhibit. Considering the equipment only for what it does, in my opinion, is very reductive compared to the historical roots of the Galilean mathematical physics contained therein. Moreover, if accurate deductions are contained in the famous study of S. Drake on the Galilean drawings and, in particular on Folio 167 v, the parabolic paths of the ball leaping from its launch pad after descending a slope really actualize Galileo's experiments. The exhibit therefore may be best known as a `Galilean calculator'.

  13. From the Icy Satellites to Small Moons and Rings: Spectral Indicators by Cassini-VIMS Unveil Compositional Trends in the Saturnian System

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Ciarniello, M.; Nicholson, P. D.; Clark, R. N.; Cuzzi, J. N.; Buratti, B. B.; Cruikshank, D. P.; Brown, R. H.

    2017-01-01

    Despite water ice being the most abundant species on Saturn satellites' surfaces and ring particles, remarkable spectral differences in the 0.35-5.0 μm range are observed among these objects. Here we report about the results of a comprehensive analysis of more than 3000 disk-integrated observations of regular satellites and small moons acquired by VIMS aboard Cassini mission between 2004 and 2016. These observations, taken from very different illumination and viewing geometries, allow us to classify satellites' and rings' compositions by means of spectral indicators, e.g. 350-550 nm - 550-950 nm spectral slopes and water ice band parameters [1,2,3]. Spectral classification is further supported by indirect retrieval of temperature by means of the 3.6 μm I/F peak wavelength [4,5]. The comparison with syntethic spectra modeled by means of Hapke's theory point to different compositional classes where water ice, amorphous carbon, tholins and CO2 ice in different quantities and mixing modalities are the principal endmembers [3, 6]. When compared to satellites, rings appear much more red at visible wavelengths and show more intense 1.5-2.0 μm band depths [7]. Our analysis shows that spectral classes are detected among the principal satellites with Enceladus and Tethys the ones with stronger water ice band depths and more neutral spectral slopes while Rhea evidences less intense band depths and more red visible spectra. Even more intense reddening in the 0.55-0.95 μm range is observed on Iapetus leading hemisphere [8] and on Hyperion [9]. With an intermediate reddening, the minor moons seems to be the spectral link between the principal satellites and main rings [10]: Prometheus and Pandora appear similar to Cassini Division ring particles. Epimetheus shows more intense water ice bands than Janus. Epimetheus' visible colors are similar to water ice rich moons while Janus is more similar to C ring particles. Finally, Dione and Tethys lagrangian satellites show a very

  14. Forum on Concepts and Approaches for Jupiter Icy Moons Orbiter

    Science.gov (United States)

    2003-01-01

    The papers presented at this conference primarily discuss instruments and techniques for conducting science on Jupiter's icy moons, and geologic processes on the moons themselves. Remote sensing of satellites, cratering on satellites, and ice on the surface of Europa are given particular attention. Some papers discuss Jupiter's atmosphere, or exobiology.

  15. Erosion, Transportation, and Deposition on Outer Solar System Satellites: Landform Evolution Modeling Studies

    Science.gov (United States)

    Moore, Jeffrey Morgan; Howard, Alan D.; Schenk, Paul M.

    2013-01-01

    Mass movement and landform degradation reduces topographic relief by moving surface materials to a lower gravitational potential. In addition to the obvious role of gravity, abrasive mechanical erosion plays a role, often in combination with the lowering of cohesion, which allows disaggregation of the relief-forming material. The identification of specific landform types associated with mass movement and landform degradation provides information about local sediment particle size and abundance and transportation processes. Generally, mass movements can be classified in terms of the particle sizes of the transported material and the speed the material moved during transport. Most degradation on outer planet satellites appears consistent with sliding or slumping, impact erosion, and regolith evolution. Some satellites, such as Callisto and perhaps Hyperion and Iapetus, have an appearance that implies that some additional process is at work, most likely sublimation-driven landform modification and mass wasting. A variant on this process is thermally driven frost segregation as seen on all three icy Galilean satellites and perhaps elsewhere. Titan is unique among outer planet satellites in that Aeolian and fluvial processes also operate to erode, transport, and deposit material. We will evaluate the sequence and extent of various landform-modifying erosional and volatile redistribution processes that have shaped these icy satellites using a 3-D model that simulates the following surface and subsurface processes: 1) sublimation and re-condensation of volatiles; 2) development of refractory lag deposits; 3) disaggregation and downward sloughing of surficial material; 4) radiative heating/cooling of the surface (including reflection, emission, and shadowing by other surface elements); 5) thermal diffusion; and 6) vapor diffusion. The model will provide explicit simulations of landform development and thusly predicts the topographic and volatile evolution of the surface

  16. Null fluids: A new viewpoint of Galilean fluids

    Science.gov (United States)

    Banerjee, Nabamita; Dutta, Suvankar; Jain, Akash

    2016-05-01

    In this article, we study a Galilean fluid with a conserved U (1 ) current up to anomalies. We construct a relativistic system, which we call a null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincaré symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in the derivative expansion. We also devise a mechanism to introduce U (1 ) anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean fluid.

  17. Generalized Galilean Algebras and Newtonian Gravity

    CERN Document Server

    Albornoz, N L González; Salgado, P; Salgado, S

    2016-01-01

    The non-relativistic versions of the generalized Poincar\\'{e} algebras and generalized $AdS$-Lorentz algebras are obtained. This non-relativistic algebras are called, generalized Galilean algebras type I and type II and denoted by $\\mathcal{G}\\mathfrak{B}_{n}$ and $\\mathcal{G}\\mathfrak{L}_{_{n}}$ respectively. Using a generalized In\\"{o}n\\"{u}--Wigner contraction procedure we find that the generalized Galilean algebras type I can be obtained from the generalized Galilean algebras type II. The $S$-expansion procedure allows us to find the $\\mathcal{G}\\mathfrak{B}_{_{5}}$ algebra from the Newton--Hooke algebra with central extension. The procedure developed in Ref. \\cite{newton} allow us to show that the non-relativistic limit of the five dimensional Einstein--Chern--Simons gravity is given by a modified version of the Poisson equation. The modification could be compatible with the effects of Dark Matter, which leads us to think that Dark Matter can be interpreted as a non-relativistic limit of Dark Energy.

  18. Is there a map between Galilean relativity and special relativity?

    OpenAIRE

    Shariati, Ahmad; Jafari, N.

    2014-01-01

    Mandanici has provided a map which he claims to be a two way map between Galilean relativity and special relativity. We argue that this map is simply a curvilinear coordinate system on a subset of the two-dimensional Minkowski space-time, and is not a two way map between 1+1 dimensional Galilean relativity and 1+1 dimensional special relativity.

  19. Null Fluids - A New Viewpoint of Galilean Fluids

    CERN Document Server

    Banerjee, Nabamita; Jain, Akash

    2015-01-01

    This article is a detailed version of our short letter `On equilibrium partition function for non-relativistic fluid' [arXiv:1505.05677] extended to include an anomalous $U(1)$ symmetry. We construct a relativistic system, which we call null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincare symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in derivative expansion. We also devise a mechanism to introduce $U(1)$ anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean Fluid.

  20. Galilean creation of the inflationary universe

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Tsutomu [Department of Physics, Rikkyo University,Toshima, Tokyo 175-8501 (Japan); Yamaguchi, Masahide [Department of Physics, Tokyo Institute of Technology,Tokyo 152-8551 (Japan); Yokoyama, Jun’ichi [Research Center for the Early Universe (RESCEU),Graduate School of Science, The University of Tokyo,Tokyo 113-0033 (Japan); Department of Physics, Graduate School of Science, The University of Tokyo,Tokyo 113-0033 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU),UTIAS, WPI, The University of Tokyo,Kashiwa, Chiba 277-8568 (Japan)

    2015-07-13

    It has been pointed out that the null energy condition can be violated stably in some non-canonical scalar-field theories. This allows us to consider the Galilean Genesis scenario in which the universe starts expanding from Minkowski spacetime and hence is free from the initial singularity. We use this scenario to study the early-time completion of inflation, pushing forward the recent idea of Pirtskhalava et al. We present a generic form of the Lagrangian governing the background and perturbation dynamics in the Genesis phase, the subsequent inflationary phase, and the graceful exit from inflation, as opposed to employing the effective field theory approach. Our Lagrangian belongs to a more general class of scalar-tensor theories than the Horndeski theory and Gleyzes-Langlois-Piazza-Vernizzi generalization, but still has the same number of the propagating degrees of freedom, and thus can avoid Ostrogradski instabilities. We investigate the generation and evolution of primordial perturbations in this scenario and show that one can indeed construct a stable model of inflation preceded by (generalized) Galilean Genesis.

  1. The formation of the Galilean moons and Titan in the Grand Tack scenario

    OpenAIRE

    Heller, René; Marleau, Gabriel-Dominique; Pudritz, Ralph Egon

    2015-01-01

    In the Grand Tack (GT) scenario for the young solar system, Jupiter formed beyond 3.5 AU from the Sun and migrated as close as 1.5 AU until it encountered an orbital resonance with Saturn. Both planets then supposedly migrated outward for several $10^5$ yr, with Jupiter ending up at ~5 AU. The initial conditions of the GT and the timing between Jupiter's migration and the formation of the Galilean satellites remain unexplored. We study the formation of Ganymede and Callisto, both of which con...

  2. Integrated Compliance Information System (ICIS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The purpose of ICIS is to meet evolving Enforcement and Compliance business needs for EPA and State users by integrating information into a single integrated data...

  3. Astrometry of mutual approximations between the Galilean moons observed at 2016

    Science.gov (United States)

    Morgado, Bruno Eduardo; Vieira-Martins, Roberto; Lainey, Valery

    2017-06-01

    A precise astrometry of natural satellites is very important to constrain dynamical models when taking into account week disturbances forces, such as tidal. For the Galilean moons of Jupiter, this astrometry is not an easy task, due to the brightness of Jupiter and its satellites. Usual CCD astrometry has a precision in the range of 100-120 mas. During the period of mutual phenomena, positions with a precision of a few mas can be obtained. However, mutual phenomena only happen during the equinox of the host planet, in the case of the Galilean moons every six years. This scenario motivates the development of alternatives methods to determine precise positions of these moons. One of these is the mutual approximations technique, in this method we determine the central instant in an apparent closest approach between two satellites. In this work, we determine the central instant of 50 curves observed from different observers. In total, 27 events were obtained, and 14 of those had at least two observers. All observations were made with a narrow-band filter centred at 889 nm with a width of 15 nm. The primary mirror of the telescopes ranges between 120-25 cm. The average precision obtained was 13 mas.

  4. Galilean Creation of the Inflationary Universe

    CERN Document Server

    Kobayashi, Tsutomu; Yokoyama, Jun'ichi

    2015-01-01

    It has been pointed out that the null energy condition can be violated stably in some non-canonical scalar-field theories. This allows us to consider the Galilean Genesis scenario in which the universe starts expanding from Minkowski spacetime and hence is free from the initial singularity. We use this scenario to study the early-time completion of inflation, pushing forward the recent idea of Pirtskhalava et al. We present a generic form of the Lagrangian governing the background and perturbation dynamics in the Genesis phase, the subsequent inflationary phase, and the graceful exit from inflation, as opposed to employing the effective field theory approach. Our Lagrangian belongs to a more general class of scalar-tensor theories than the Horndeski theory and Gleyzes-Langlois-Piazza-Vernizzi generalization, but still has the same number of the propagating degrees of freedom, and thus can avoid Ostrogradski instabilities. We investigate the generation and evolution of primordial perturbations in this scenario...

  5. Aspects of infinite dimensional ℓ-super Galilean conformal algebra

    Science.gov (United States)

    Aizawa, N.; Segar, J.

    2016-12-01

    In this work, we construct an infinite dimensional ℓ-super Galilean conformal algebra, which is a generalization of the ℓ = 1 algebra found in the literature. We give a classification of central extensions, the vector field representation, the coadjoint representation, and the operator product expansion of the infinite dimensional ℓ-super Galilean conformal algebra, keeping possible applications in physics and mathematics in mind.

  6. Ehrenfest theorem, Galilean invariance and nonlinear Schr"odinger equations

    CERN Document Server

    Kälbermann, G

    2003-01-01

    Galilean invariant Schr"odinger equations possessing nonlinear terms coupling the amplitude and the phase of the wave function can violate the Ehrenfest theorem. An example of this kind is provided. The example leads to the proof of the theorem: A Galilean invariant Schr"odinger equation derived from a lagrangian density obeys the Ehrenfest theorem. The theorem holds for any linear or nonlinear lagrangian.

  7. Observations of the Galilean moons of Jupiter in 2013-2015 at Pulkovo

    Science.gov (United States)

    Narizhnaya, N. V.

    2016-09-01

    Observational results are presented for Jupiter and its Galilean moons from the Normal Astrograph at Pulkovo Observatory in 2013-2015. The following data are obtained: 154 positions of the Galilean satellites and 47 calculated positions of Jupiter in the system of the UCAC4 (ICRS, J2000.0) catalogue; the differential coordinates of the satellites relative to one another are determined. The mean errors of the satellites' normal places in right ascension and declination over the entire observational period are, respectively: ɛα = 0.0065″ and ɛδ = 0.0068″, and their standard deviations are σα = 0.0804″ and σδ = 0.0845″. The equatorial coordinates are compared with planetary and satellite motion theories. The average (O-C) residuals in the two coordinates relative to the motion theories are 0.05″ or less. The best agreement with the observations is achieved by a combination of the EPM2011m and V. Lainey-V.2.0|V1.1 motion theories; the average (O-C) residuals are 0.03″ or less. The (O-C) residuals for the features of the positions of Io and Ganymede are comparable with measurement errors. Jupiter's positions calculated from the observations of the satellites and their theoretical jovicentric coordinates are in good agreement with the motion theories. The (O-C) residuals for Jupiter's coordinates are, on average, 0.027″ and-0.025″ in the two coordinates.

  8. INEXTENSIBLE FLOWS OF CURVES IN THE EQUIFORM GEOMETRY OF THE PSEUDO-GALILEAN SPACE G13

    Directory of Open Access Journals (Sweden)

    HANDAN OZTEKIN

    2016-12-01

    Full Text Available In this paper, we study inextensible ows of curves in 3-dimensional pseudo- Galilean space. We give necessary and sucient conditions for inextensible ows of curves according to equiform geometry in pseudo-Galilean space.

  9. Covariant effective action for a Galilean invariant quantum Hall system

    Science.gov (United States)

    Geracie, Michael; Prabhu, Kartik; Roberts, Matthew M.

    2016-09-01

    We construct effective field theories for gapped quantum Hall systems coupled to background geometries with local Galilean invariance i.e. Bargmann spacetimes. Along with an electromagnetic field, these backgrounds include the effects of curved Galilean spacetimes, including torsion and a gravitational field, allowing us to study charge, energy, stress and mass currents within a unified framework. A shift symmetry specific to single constituent theories constraints the effective action to couple to an effective background gauge field and spin connection that is solved for by a self-consistent equation, providing a manifestly covariant extension of Hoyos and Son's improvement terms to arbitrary order in m.

  10. Galilean Relativity and the Work-Kinetic Energy Theorem

    Science.gov (United States)

    Tefft, Brandon J.; Tefft, James A.

    2007-01-01

    As the topic of relativity is developed in a first-year physics class, there seems to be a tendency to move as quickly as possible to the fascinating ideas set forth in Einstein's special theory of relativity. In this paper we linger a little with the Galilean side of relativity and discuss an intriguing problem and its solution to illustrate a…

  11. Galilean Relativity and the Work-Kinetic Energy Theorem

    Science.gov (United States)

    Tefft, Brandon J.; Tefft, James A.

    2007-01-01

    As the topic of relativity is developed in a first-year physics class, there seems to be a tendency to move as quickly as possible to the fascinating ideas set forth in Einstein's special theory of relativity. In this paper we linger a little with the Galilean side of relativity and discuss an intriguing problem and its solution to illustrate a…

  12. On the Galilean Non-Invariance of Classical Electromagnetism

    Science.gov (United States)

    Preti, Giovanni; de Felice, Fernando; Masiero, Luca

    2009-01-01

    When asked to explain the Galilean non-invariance of classical electromagnetism on the basis of pre-relativistic considerations alone, students--and sometimes their teachers too--may face an impasse. Indeed, they often argue that a pre-relativistic physicist could most obviously have provided the explanation "at a glance", on the basis of the…

  13. ICIS FE&C Compliance Monitoring Screens

    Data.gov (United States)

    U.S. Environmental Protection Agency — Web Based Training for Integrated Compliance Information System Updated Compliance Monitoring Training for ICIS Federal Enforcement and Compliance User. This...

  14. Galilean Equivalence for Galactic Dark Matter

    CERN Document Server

    Kesden, M; Kesden, Michael; Kamionkowski, Marc

    2006-01-01

    Satellite galaxies of the Milky Way experience a tidal disruption as they orbit in the Milky Way's dark halo. While the bound core of the satellite remains dominated by dark matter, the tidally disrupted stars behave like purely baryonic tracers of the Milky Way's potential well. If dark matter experiences a stronger self attraction than visible matter, stars will preferentially gain rather than lose energy during tidal disruption. This leads to a relative enhancement in the trailing as compared to the leading tidal stream. We show that the absence of a strong asymmetry in the surface brightness of the leading and trailing tidal streams already constrains the equivalence of acceleration of dark matter and baryons in a gravitational field to less than ten percent--thus ruling out a recently proposed mechanism to clear dwarf galaxies from voids. Future observations should be sensitive at the percent level to departures from the equivalence of dark matter and baryons.

  15. Extended Galilean symmetries of non-relativistic strings

    Science.gov (United States)

    Batlle, Carles; Gomis, Joaquim; Not, Daniel

    2017-02-01

    We consider two non-relativistic strings and their Galilean symmetries. These strings are obtained as the two possible non-relativistic (NR) limits of a relativistic string. One of them is non-vibrating and represents a continuum of non-relativistic massless particles, and the other one is a non-relativistic vibrating string. For both cases we write the generator of the most general point transformation and impose the condition of Noether symmetry. As a result we obtain two sets of non-relativistic Killing equations for the vector fields that generate the symmetry transformations. Solving these equations shows that NR strings exhibit two extended, infinite dimensional space-time symmetries which contain, as a subset, the Galilean symmetries. For each case, we compute the associated conserved charges and discuss the existence of non-central extensions.

  16. Extended Galilean symmetries of non-relativistic strings

    CERN Document Server

    Batlle, Carles; Not, Daniel

    2016-01-01

    We consider two non-relativistic strings and their Galilean symmetries. These strings are obtained as the two possible non-relativistic (NR) limits of a relativistic string. One of them is non-vibrating and represents a continuum of non-relativistic massless particles, and the other one is a non-relativistic vibrating string. For both cases we write the generator of the most general point transformation and impose the condition of Noether symmetry. As a result we obtain two sets of non-relativistic Killing equations for the vector fields that generate the symmetry transformations. Solving these equations shows that NR strings exhibit two extended, infinite dimensional space-time symmetries which contain, as a subset, the Galilean symmetries. For each case, we compute the associated conserved charges and discuss the existence of non-central extensions.

  17. Higher spin holography with Galilean symmetry in general dimensions

    CERN Document Server

    Lei, Yang

    2015-01-01

    We construct Schroedinger-like solutions of the Vasiliev higher spin theory in D>3 dimension. Symmetries of such solutions and the linearised equation of motion for the scalar on such backgrounds are analysed. We further propose Galilean invariant bosonic and fermionic field theories that could be dual to the two parity invariant higher spin theories on the Schroedinger-like background respectively. The discussion is phrased mainly in D=4 dimension, while similar constructions follow straightforwardly in higher dimensions.

  18. On some applications of Galilean electrodynamics of moving bodies

    OpenAIRE

    2006-01-01

    We discuss the seminal article in which Le Bellac and L\\'{e}vy-Leblond have identified two Galilean limits of electromagnetism [1], and its modern implications. Recent works have shed a new light on the choice of gauge conditions in classical electromagnetism. We discuss various applications and experiments, such as in quantum mechanics, superconductivity, electrodynamics of continuous media, etc. Much of the current technology, where waves are not taken into account, is actually based on Gal...

  19. Cosmic ion bombardment of the icy moons of Jupiter

    Energy Technology Data Exchange (ETDEWEB)

    Strazzulla, G., E-mail: gianni@oact.inaf.i [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania (Italy)

    2011-05-01

    A large number of experiments have been performed in many laboratories in the world with the aim to investigate the physico-chemical effects induced by fast ions irradiating astrophysical relevant materials. The laboratory in Catania (Italy) has given a contribution to some experimental works. In this paper I review the results of two class of experiments performed by the Catania group, namely implantation of reactive (H{sup +}, C{sup +}, N{sup +}, O{sup +} and S{sup +}) ions in ices and the ion irradiation induced synthesis of molecules at the interface between water ice and carbonaceous or sulfurous solid materials. The results, discussed in the light of some questions concerning the surfaces of the Galilean moons, contribute to understand whether minor molecular species (CO{sub 2}, SO{sub 2}, H{sub 2}SO{sub 4}, etc.) observed on those objects are endogenic i.e. native from the satellite or are produced by exogenic processes, such as ion implantation. The results indicate that: - C-ion implantation is not the dominant formation mechanism of CO{sub 2} on Europa, Ganimede and Callisto. - Implantation of sulfur ions into water ice produces hydrated sulfuric acid with high efficiency such to give a very important contribution to the sulfur cycle on the surface of Europa and other satellites. - Implantation of protons into carbon dioxide produces some species containing the projectile (H{sub 2}CO{sub 3}, and O-H in poly-water). - Implantation of protons into sulfur dioxide produces SO{sub 3}, polymers, and O{sub 3} but not H-S bonds. - Water ice has been deposited on refractory carbonaceous materials: a general finding is the formation of a noteworthy quantity of CO{sub 2}. We suggest that this is the primary mechanism to explain the presence of carbon dioxide on the surfaces of the Galilean satellites. -Water ice has been deposited on refractory sulfurous materials originating from SO{sub 2} or H{sub 2}S irradiation. No evidence for an efficient synthesis of SO{sub 2

  20. On the Galilean non-invariance of classical electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Preti, Giovanni; De Felice, Fernando; Masiero, Luca [Dipartimento di Fisica ' Galileo Galilei' , Universita degli Studi di Padova (Italy)], E-mail: giovanni.preti@pd.infn.it, E-mail: fernando.defelice@pd.infn.it, E-mail: masieroluca@yahoo.it

    2009-03-15

    When asked to explain the Galilean non-invariance of classical electromagnetism on the basis of pre-relativistic considerations alone, students-and sometimes their teachers too-may face an impasse. Indeed, they often argue that a pre-relativistic physicist could most obviously have provided the explanation 'at a glance', on the basis of the presence of a parameter c with the dimensions of a velocity in Maxwell's equations, being well aware of the fact that any velocity is non-invariant in Galilean relativity. This 'obvious' answer, however popular, is not correct due to the actual observer-invariance of the Maxwell parameter c in pre-relativistic physics too. A pre-relativistic physicist would therefore have needed a different explanation. Playing the role of this physicist, we pedagogically show how a proof of the Galilean non-invariance of classical electromagnetism can be obtained, resting on simple pre-relativistic considerations alone.

  1. Reheating and Primordial Gravitational Waves in Generalized Galilean Genesis

    CERN Document Server

    Nishi, Sakine

    2016-01-01

    Galilean genesis is an alternative to inflation, in which the universe starts expanding from Minkowski with the stable violation of the null energy condition. In this paper, we discuss how the early universe is reheated through the gravitational particle production at the trasition from the genesis phase to the subsequent phase where the kinetic energy of the scalar field is dominant. We then study the consequences of gravitational reheating after Galilean genesis on the spectrum of primordial gravitational waves. The resultant spectrum is strongly blue, and at high frequencies $\\Omega_{\\rm gw}\\propto f^3$ in terms of the energy density per unit logarithmic frequency. Though this cannot be detected in existing detctors, the amplitude can be as large as $\\Omega_{\\rm gw}\\sim 10^{-12}$ at $f\\sim 100\\,$MHz, providing a future test of the genesis scenario. The analysis is performed within the framework of generalized Galilean genesis based on the Horndeski theory, which enables us to derive generic formulas.

  2. The chemical composition of the Galileian satellites

    CERN Document Server

    Celebonovic, V

    1998-01-01

    Using the semiclassical theory of dense matter proposed by P.Savic and R.Kasanin,the mean molecular masses of the Galilean satellites of Jupiter are determined.The calculated values are fitted by plausible combinations of chemical elements,and the results are in good agreement with the observations by "Galileo".Possible cosmogonical explanations are briefly discussed.

  3. Plasma IMS Composition Measurements for Europa and the Other Galilean Moons

    Science.gov (United States)

    Sittler, Edward; Cooper, John; Hartle, Richard; Lipatov, Alexander; Mahaffy, Paul; Paterson, William; Pachalidis, Nick; Coplan, Mike; Cassidy, Tim

    2010-01-01

    NASA and ESA are planning the joint Europa Jupiter System Mission (EJSM) to the Jupiter system with specific emphasis to Europa and Ganymede, respectively. The Japanese Space Agency is also planning an orbiter mission to explore Jupiter's magnetosphere and the Galilean satellites. For NASA's Jupiter Europa Orbiter (JEO) we are developing the 3D Ion Mass Spectrometer (IMS) with two main goals which can also be applied to the other Galilean moons, 1) measure the plasma interaction between Europa and Jupiter's magnetosphere and 2) infer the 4 pi surface composition to trace elemental and significant isotopic levels. The first goal supports the magnetometer (MAG) measurements, primarily directed at detection of Europa's sub-surface ocean, while the second gives information about transfer of material between the Galilean moons, and between the moon surfaces and subsurface layers putatively including oceans. The measurement of the interactions for all the Galilean moons can be used to trace the in situ ion measurements of pickup ions back to either Europa's or Ganymede's surface from the respectively orbiting spacecraft. The IMS instrument, being developed under NASA's Astrobiology Instrument Development Program, would maximally achieve plasma measurement requirements for JEO and EJSM while moving forward our knowledge of Jupiter system composition and source processes to far higher levels than previously envisaged. The composition of the global surfaces of Europa and Ganymede can be inferred from the measurement of ejected neutrals and pick-up ions using at minimum an in situ payload including MAG and IMS also fully capable of meeting Level 1 mission requirements for ocean detection and survey. Elemental and isotopic analysis of potentially extruded oceanic materials at the moon surfaces would further support the ocean objectives. These measurements should be made from a polar orbiting spacecraft about Europa or Ganymede at height 100 km. The ejecta produced by

  4. ICIS2005印象

    Institute of Scientific and Technical Information of China (English)

    董阳泽

    2006-01-01

    International Conference on Intelligent Systems(ICIS2005,2005年国际智能系统大会)于2005年12月1-3日在马来西亚吉隆坡举行。此次会议由马来西亚高等教育部批准,马来西来国家石油公司Petronas主赞助,Universiti Teknologi Petronas主办。参加会议的有来自中国、美国、日本、英国、马来西亚、印度等30个国家的200余篇论文作者及相关领域的研究人员。马来西来高等教育部部长Y.B.Dato’Sri Dr Haji Shafie Hj.Mohd Salleh亲临开幕式并致欢迎辞。

  5. Second central extension in Galilean covariant field theory

    CERN Document Server

    Hagen, C R

    2002-01-01

    The second central extension of the planar Galilei group has been alleged to have its origin in the spin variable. This idea is explored here by considering local Galilean covariant field theory for free fields of arbitrary spin. It is shown that such systems generally display only a trivial realization of the second central extension. While it is possible to realize any desired value of the extension parameter by suitable redefinition of the boost operator, such an approach has no necessary connection to the spin of the basic underlying field.

  6. Wess-Zumino-Witten Model for Galilean Conformal Algebra

    CERN Document Server

    Chakraborty, Somdeb

    2012-01-01

    In this note, we construct a Wess-Zumino-Witten model based on the Galilean conformal algebra in 2-spacetime dimensions, which is a nonrelativistic analogue of the relativistic conformal algebra. We obtain exact background corresponding to \\sigma-models in six dimensions (the dimension of the group manifold) and a central charge c=6. We carry out a Sugawara type construction to verify the conformal invariance of the model. Further, we discuss the feasibility of the background obtained as a physical spacetime metric.

  7. Exotic Galilean Symmetry and Non-Commutative Mechanics

    Directory of Open Access Journals (Sweden)

    Peter A. Horváthy

    2010-07-01

    Full Text Available Some aspects of the ''exotic'' particle, associated with the two-parameter central extension of the planar Galilei group are reviewed. A fundamental property is that it has non-commuting position coordinates. Other and generalized non-commutative models are also discussed. Minimal as well as anomalous coupling to an external electromagnetic field is presented. Supersymmetric extension is also considered. Exotic Galilean symmetry is also found in Moyal field theory. Similar equations arise for a semiclassical Bloch electron, used to explain the anomalous/spin/optical Hall effects.

  8. Torsional Newton-Cartan geometry from Galilean gauge theory

    CERN Document Server

    Banerjee, Rabin

    2016-01-01

    Using the recently advanced Galilean gauge theory we give a comprehensive construction of torsional Newton Cartan geometry. A complete (implicit) expression of the torsion tensor for the Newton Cartan spacetime is provided. The implicit expression containing torsion is similar to contorsion tensor in Riemann - Cartan space time and it contains an arbitrary shift. This is similar to the shift given by Dautcourt's formula for the symmetric part of the connection. These findings are new in the literature. The well known result for the temporal part of torsion is reproduced from our expression.

  9. The compression behavior of blödite at low and high temperature up to ~10GPa: Implications for the stability of hydrous sulfates on icy planetary bodies

    Energy Technology Data Exchange (ETDEWEB)

    Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra; Fei, Yingwei; Prakapenka, Vitali

    2017-03-01

    Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ~10.4 GPa and temperatures from ~118.8 K to ~490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperature equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede.

  10. PAINT SUPPLIES AND LOCATION: EXAMINING ICI

    Directory of Open Access Journals (Sweden)

    M. Herron

    2016-01-01

    Full Text Available How important is location to an international retailer? Not just any retailer but the second largest paint retailer in the world. Imperial Chemical Industries (ICI was a British chemical company and was at one stage the largest manufacturer in Britain. Formed from the merger of several leading British chemical companies in 1926, ICI makes paints and speciality products, including food ingredients, speciality polymers, electronic materials, fragrances and flavourings. ICI paints purchased the Cleveland Ohiobased Glidden Coatings & Resins (Glidden Paint Company in 1986 for USD$580 million. The addition of Glidden to ICI's North American operations more than doubled that subsidiary's annual sales to $3 billion and increased ICI's corporate presence in the United States dramatically. A decline in paint and solvent consumption during the 2000 decade slowed the average growth of the paint industry to about 2% annually. Rauch Associates, the leading US paint analyst firm, predicted near-term growth to slow even further to 1.2% per annum. Through the 1990’s and early 2000’s Glidden paint was sold only through Glidden-badged paint stores and smaller retailers under licence, developing a strong identifiable brand and reputation. How were potential Glidden retail paint store locations chosen across America to enable and support this market growth? This paper investigates the real process that was developed and applied to construct a national network of retail outlets across the United States. It also highlights the change in direction that occurred at ICI paints culminating in its eventual acquisition by AkzoNobel in 2008 who immediately sold parts of ICI to Henkel, and integrated ICI's remaining operations within its existing organisation. This sale and the associated corporate restructure caused considerable change in marketing directions allowing for the first time the selling of Glidden paint products to mass market centres

  11. The formation of the Galilean moons and Titan in the Grand Tack scenario

    CERN Document Server

    Heller, René; Pudritz, Ralph Egon

    2015-01-01

    In the "Grand Tack" (GT) scenario for the young solar system, Jupiter formed beyond 3.5 AU from the Sun and migrated as close as 1.5 AU until it encountered an orbital resonance with Saturn. Both planets then supposedly migrated outward for several $10^5$ yr, with Jupiter ending up at ~5 AU. The initial conditions of the GT and the timing between Jupiter's migration and the formation of the Galilean satellites remain unexplored. We study the formation of Ganymede and Callisto, both of which consist of ~50% water and rock, respectively, in the GT scenario. We examine why they lack dense atmospheres, while Titan is surrounded by a thick nitrogen envelope. We model an axially symmetric circumplanetary disk (CPD) in hydrostatic equilibrium around Jupiter. The CPD is warmed by viscous heating, Jupiter's luminosity, accretional heating, and the Sun. The position of the water ice line in the CPD, which is crucial for the formation of massive moons, is computed at various solar distances. We assess the loss of Galile...

  12. Search for volatiles on icy satellites. I. Europa

    Science.gov (United States)

    Brown, R.H.; Cruikshank, D.P.; Tokunaga, A.T.; Smith, R.G.; Clark, R.N.

    1988-01-01

    New reflectance spectra have been obtained for both the leading and trailing sides of Europa, using the Cooled Grating Array Spectrometer (CGAS) of the NASA Infrared Telescope Facility (IRTF). The spectra are of higher precision than any yet obtained. Spectra of Europa's trailing side (central meridian longitude ???300??) obtained in 1985 show two weak absorptions near 2.2 and 2.3 ??m. Both of these features as well as others are seen in spectra obtained by R. N. Clark, R. B. Singer, P. D. Owensby, and F.P. Fanale (1980a, Bull. Amer. Astron. Soc. 12, 713-714) at similar central meridian longitude. Data obtained with an improved detector array in 1986, however, do not show the absorptions seen in the 1980 and 1985 spectra. It is not clear why the newest data do not show the apparent absorptions seen in previous years, but the suggestion is that either the 1980 and 1985 data are spurious or that the material responsible for the weak absorptions is no longer detectable. Analysis of the 1980 and 1985 data did not reveal any obvious source of systematic error capable of introducing spurious features, but we are skeptical of any explanation that cites transient deposition, movement, and/or destruction of material on Europa's trailing side to account for the nondetection of the features in the 1986 data. If the weak absorptions seen in the 1980 and 1985 data are real, they can be interpreted as indicating the transient spectroscopic presence of a molecular component on Europa's trailing side different from the water ice that is known to be the dominant surface constituent. Further monitoring is required to determine if the apparent absorptions are real. ?? 1988.

  13. Europa--Jupiter's Icy Ocean Moon

    Science.gov (United States)

    Lowes, L.

    1999-01-01

    Europa is a puzzle. The sixth largest moon in our solar system, Europa confounds and intrigues scientists. Few bodies in the solar system have attracted as much scientific attention as this moon of Jupiter because of its possible subsurface ocean of water. The more we learn about this icy moon, the more questions we have.

  14. Schwarzschild-type solution in an effective gravitational theory with local Galilean invariance

    CERN Document Server

    Cuzinatto, R R; De Montigny, M; Khanna, F C

    2009-01-01

    We construct a Schwarzschild-type exact external solution for a theory of gravity admitting local Galilean invariance. In order to realize the Galilean invariance we need to adopt a five-dimensional manifold. The solution for the gravitational field equations obeys a Birkhoff-like theorem. Three classic tests of general relativity are analyzed in detail: the perihelion shift of the planet Mercury, the deflection of light by the Sun, and the gravitational redshift of atomic spectral lines. The Galilean version of these tests exhibits an additional parameter $b$ related to the fifth-coordinate. This constant $b$ can be estimated by a comparison with observational data. We observe that the Galilean theory is able to reproduce the results traditionally predicted by general relativity in the limit of negligible $b$. This shows that the tests are not specifically Lorentz invariant.

  15. Galilean symmetry in generalized Abelian Schrödinger-Higgs models with and without gauge field interaction

    Science.gov (United States)

    Sourrouille, Lucas

    2015-11-01

    We consider a generalization of non-relativistic Schrödinger-Higgs Lagrangian by introducing a nonstandard kinetic term. We show that this model is Galilean invariant, we construct the conserved charges associated to the symmetries and realize the algebra of the Galilean group. In addition, we study the model in the presence of a gauge field. We also show that the gauged model is Galilean invariant. Finally, we explore relations between the twin models and their solutions.

  16. Space Environmental Erosion of Polar Icy Regolith

    Science.gov (United States)

    Farrell, William M.; Killen, R. M.; Vondrak, R. R.; Hurley, D. M.; Stubbs, T. J.; Delory, G. T.; Halekas, J. S.; Zimmerman, M. I.

    2011-01-01

    While regions at the floors of permanently shadowed polar craters are isolated from direct sunlight, these regions are still exposed to the harsh space environment, including the interplanetary Lyman-a background, meteoric impacts, and obstacle-affected solar wind. We demonstrate that each of these processes can act to erode the polar icy regolith located at or near the surface along the crater floor. The Lyman-a background can remove/erode the icy-regolith via photon stimulated desorption [1], meteoric impacts can vaporize the regolith [2], and redirected solar wind ions can sputter the ice-regolith mix [3]. As an example we shall examine in detail the inflow of solar wind ions and electrons into polar craters, One might expect such ions to flow horizontally over the crater top (see Figure). However, we find that plasma ambipolar processes act to deflect passing ions into the craters [3]. We examine this plasma process and determine the ion flux as a function of position across a notional crater floor. We demonstrate that inflowing solar wind ions can indeed create sputtering along the crater floor, effectively eroding the surface. Erosion time scales rrom sputtering will be presented. We shall also consider the effect of impact vaporization on buried icy-regolith regions. There will also be a discussion of solar wind electrons that enter into the PSR, demonstrating that these also have the ability rree surface-bound atoms via electron stimulated desorption processes [l].

  17. Plasma IMS Composition Measurements for Europa and the Other Galilean Moons

    Science.gov (United States)

    Sittler, Edward; Cooper, John; Hartle, Richard; Lipatov, Alexander; Mahaffy, Paul; Paterson, William; Pachalidis, Nick; Coplan, Mike; Cassidy, Tim

    2010-05-01

    NASA and ESA are planning the joint Europa Jupiter System Mission (EJSM) to the Jupiter system with specific emphasis to Europa and Ganymede, respectively. The Japanese Space Agency is also planning an orbiter mission to explore Jupiter's magnetosphere and the Galilean satellites. For NASA's Jupiter Europa Orbiter (JEO) we are developing the 3D Ion Mass Spectrometer (IMS) with two main goals which can also be applied to the other Galilean moons, 1) measure the plasma interaction between Europa and Jupiter's magnetosphere and 2) infer the 4? surface composition to trace elemental [1] and significant isotopic levels. The first goal supports the magnetometer (MAG) measurements, primarily directed at detection of Europa's sub-surface ocean, while the second gives information about transfer of material between the Galilean moons, and between the moon surfaces and subsurface layers putatively including oceans. The measurement of the interactions for all the Galilean moons can be used to trace the in situ ion measurements of pickup ions back to either Europa's or Ganymede's surface from the respectively orbiting spacecraft. The IMS instrument, being developed under NASA's Astrobiology Instrument Development Program, would maximally achieve plasma measurement requirements for JEO and EJSM while moving forward our knowledge of Jupiter system composition and source processes to far higher levels than previously envisaged. The composition of the global surfaces of Europa and Ganymede can be inferred from the measurement of ejected neutrals and pick-up ions using at minimum an in situ payload including MAG and IMS also fully capable of meeting Level 1 mission requirements for ocean detection and survey. Elemental and isotopic analysis of potentially extruded oceanic materials at the moon surfaces would further support the ocean objectives. These measurements should be made from a polar orbiting spacecraft about Europa or Ganymede at height ~ 100 km. The ejecta produced by

  18. Glaciers and Ice Sheets As Analog Environments of Potentially Habitable Icy Worlds

    Directory of Open Access Journals (Sweden)

    Eva Garcia-Lopez

    2017-07-01

    Full Text Available Icy worlds in the solar system and beyond have attracted a remarkable attention as possible habitats for life. The current consideration about whether life exists beyond Earth is based on our knowledge of life in terrestrial cold environments. On Earth, glaciers and ice sheets have been considered uninhabited for a long time as they seemed too hostile to harbor life. However, these environments are unique biomes dominated by microbial communities which maintain active biochemical routes. Thanks to techniques such as microscopy and more recently DNA sequencing methods, a great biodiversity of prokaryote and eukaryote microorganisms have been discovered. These microorganisms are adapted to a harsh environment, in which the most extreme features are the lack of liquid water, extremely cold temperatures, high solar radiation and nutrient shortage. Here we compare the environmental characteristics of icy worlds, and the environmental characteristics of terrestrial glaciers and ice sheets in order to address some interesting questions: (i which are the characteristics of habitability known for the frozen worlds, and which could be compatible with life, (ii what are the environmental characteristics of terrestrial glaciers and ice sheets that can be life-limiting, (iii What are the microbial communities of prokaryotic and eukaryotic microorganisms that can live in them, and (iv taking into account these observations, could any of these planets or satellites meet the conditions of habitability? In this review, the icy worlds are considered from the point of view of astrobiological exploration. With the aim of determining whether icy worlds could be potentially habitable, they have been compared with the environmental features of glaciers and ice sheets on Earth. We also reviewed some field and laboratory investigations about microorganisms that live in analog environments of icy worlds, where they are not only viable but also metabolically active.

  19. Habitability potential of icy moons: a comparative study

    Science.gov (United States)

    Solomonidou, Anezina; Coustenis, Athena; Encrenaz, Thérèse; Sohl, Frank; Hussmann, Hauke; Bampasidis, Georgios; Wagner, Frank; Raulin, François; Schulze-Makuch, Dirk; Lopes, Rosaly

    2014-05-01

    Looking for habitable conditions in the outer solar system our research focuses on the natural satellites rather than the planets themselves. Indeed, the habitable zone as traditionally defined may be larger than originally con-ceived. The strong gravitational pull caused by the giant planets may produce enough energy to sufficiently heat the interiors of orbiting icy moons. The outer solar system satellites then provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the ground but also by the Voyager, Galileo and the Cassini spacecrafts revealed the potential of these satellites in this context, and our understanding of habitability in the solar system and beyond can be greatly enhanced by investigating several of these bodies together [1]. Their environments seem to satisfy many of the "classical" criteria for habitability (liquid water, energy sources to sustain metabolism and chemical compounds that can be used as nutrients over a period of time long enough to allow the development of life). Indeed, several of the moons show promising conditions for habitability and the de-velopment and/or maintenance of life. Europa, Callisto and Ganymede may be hiding, under their icy crust, putative undersurface liquid water oceans [3] which, in the case of Europa [2], may be in direct contact with a silicate mantle floor and kept warm by tidally generated heat [4]. Titan and Enceladus, Saturn's satellites, were found by the Cassini-Huygens mission to possess active organic chemistries with seasonal variations, unique geological features and possibly internal liquid water oceans. Titan's rigid crust and the probable existence of a subsurface ocean create an analogy with terrestrial-type plate tectonics, at least surficial [5], while Enceladus' plumes find an analogue in gey-sers. As revealed by Cassini the liquid hydrocarbon lakes [6] distributed mainly at polar latitudes on Titan are ideal isolated

  20. X-MIME: An Imaging X-ray Spectrometer for Detailed Study of Jupiter's Icy Moons and the Planet's X-ray Aurora

    Science.gov (United States)

    Elsner, R. F.; Ramsey, B. D.; Waite, J. H.; Rehak, P.; Johnson, R. E.; Cooper, J. F.; Swartz, D. A.

    2004-01-01

    Remote observations with the Chandra X-ray Observatory and the XMM-Newton Observatory have shown that the Jovian system is a source of x-rays with a rich and complicated structure. The planet's polar auroral zones and its disk are powerful sources of x-ray emission. Chandra observations revealed x-ray emission from the Io Plasma Torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from these moons is certainly due to bombardment of their surfaces of highly energetic protons, oxygen and sulfur ions from the region near the Torus exciting atoms in their surfaces and leading to fluorescent x-ray emission lines. Although the x-ray emission from the Galilean moons is faint when observed from Earth orbit, an imaging x-ray spectrometer in orbit around these moons, operating at 200 eV and above with 150 eV energy resolution, would provide a detailed mapping (down to 40 m spatial resolution) of the elemental composition in their surfaces. Such maps would provide important constraints on formation and evolution scenarios for the surfaces of these moons. Here we describe the characteristics of X-MIME, an imaging x-ray spectrometer under going a feasibility study for the JIMO mission, with the ultimate goal of providing unprecedented x-ray studies of the elemental composition of the surfaces of Jupiter's icy moons and Io, as well as of Jupiter's auroral x-ray emission.

  1. ON THE GAUSS MAP OF RULED SURFACES OF TYPE II IN 3-DIMENSIONAL PSEUDO-GALILEAN SPACE

    Directory of Open Access Journals (Sweden)

    Alper Osman Öğrenmis

    2013-02-01

    Full Text Available In this paper, ruled surfaces of type II in a three-dimensional Pseudo-Galilean space are given. By studying its Gauss map and Laplacian operator, we obtain a classification of ruled surfaces of type II in a three-dimensional Pseudo-Galilean space.

  2. A Covariant Master Theory for Novel Galilean Invariant Models and Massive Gravity

    CERN Document Server

    Gabadadze, Gregory; Khoury, Justin; Pirtskhalava, David; Trodden, Mark

    2012-01-01

    Coupling the galileons to a curved background has been a tradeoff between maintaining second order equations of motion, maintaining the galilean shift symmetries, and allowing the background metric to be dynamical. We propose a construction which can achieve all three for a novel class of galilean invariant models, by coupling a scalar with the galilean symmetry to a massive graviton. This generalizes the brane construction for galileons, by adding to the brane a dynamical metric, (non-universally) interacting with the galileon field. Alternatively, it can be thought of as an extension of the ghost-free massive gravity, or as a massive graviton-galileon scalar-tensor theory. In the decoupling limit of these theories, new kinds of galileon invariant interactions arise between the scalar and the longitudinal mode of the graviton. These have higher order equations of motion and infinite powers of the field, yet are ghost-free.

  3. EPA Enforcement and Compliance History Online: ICIS-NPDES Limit

    Data.gov (United States)

    U.S. Environmental Protection Agency — Integrated Compliance Information System (ICIS) National Pollutant Discharge Elimination System (NPDES) Permit Limits data set for Clean Water Act permitted...

  4. Galilean quantum gravity with cosmological constant and the extended q-Heisenberg algebra

    OpenAIRE

    Papageorgiou, G; Schroers, B. J.

    2010-01-01

    We define a theory of Galilean gravity in 2+1 dimensions with cosmological constant as a Chern-Simons gauge theory of the doubly-extended Newton-Hooke group, extending our previous study of classical and quantum gravity in 2+1 dimensions in the Galilean limit. We exhibit an r-matrix which is compatible with our Chern-Simons action (in a sense to be defined) and show that the associated bi-algebra structure of the Newton-Hooke Lie algebra is that of the classical double of the extended Heisenb...

  5. L'espion d'ici

    CERN Document Server

    Omnes, Roland

    2000-01-01

    On les appelle " ceux-qui-savent-le-savoir-inutile ". De leur planète puissante qui répond au nom orgueilleux d'" Ici ", ils dépêchent sur Terre un agent : à charge pour lui d'évaluer l'état d'avancement des connaissances chez les humains et de mesurer les risques que ceux-ci représentent. L'espion sera introduit auprès des sages grecs, il s'initiera aux mystères de Pythagore, il tiendra tête à Aristote, il se réincarnera en Merlin, il fréquentera le salon de Mme du Châtelet, il s'entretiendra avec Darwin, il côtoiera Einstein, il assistera à la naissance de la mécanique quantique, il fera un détour par les cafés de philosophie... Au terme de ses pérégrinations, il devra finalement choisir. Prendra-t-il le parti d'" Ici ", dont les connaissances plongent dans des temps insondables, ou celui de la Terre, au savoir étonnamment neuf ?

  6. IPPF Co-operative Information Service (ICIS). November 1977.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    This ICIS bulletin replaces the formal Library Bulletin of the International Planned Parenthood Federation (IPPF). It represents the integration of a bibliographic information network. Entries in ICIS are classified according to the following nine categories: (0) General Reference; (1) IPPF; (2) Family Planning and Health Care; (3) Biomedical…

  7. IPPF Co-operative Information Service (ICIS). August 1977.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    The pooling of documentation service resources has resulted in the creation of an International Planned Parenthood Federation (IPPF) integrated bibliographic information system. The former Library Bulletin has become IPPF Cooperative Information Service (ICIS). Entries in ICIS are classified according to the following nine categories: (0) General…

  8. IPPF Co-operative Information Service (ICIS). May 1977.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    The pooling of documentation service resources has resulted in the creation of an International Planned Parenthood Federation (IPPF) integrated bibliographic information system. Thus, the former Library Bulletin has become IPPF Cooperative Information Service (ICIS). This is the first such publication. Entries in ICIS are classified according to…

  9. Geometry of the Solutions of Localized Induction Equation in the Pseudo-Galilean Space

    Directory of Open Access Journals (Sweden)

    Muhittin Evren Aydin

    2015-01-01

    Full Text Available We study the surfaces corresponding to solutions of the localized induction equation in the pseudo-Galilean space G31. We classify such surfaces with null curvature and characterize some special curves on these surfaces in G31.

  10. Galilean Moons, Kepler's Third Law, and the Mass of Jupiter

    Science.gov (United States)

    Bates, Alan

    2013-01-01

    Simulations of physical systems are widely available online, with no cost, and are ready to be used in our classrooms. Such simulations offer an accessible tool that can be used for a range of interactive learning activities. The Jovian Moons Apple allows the user to track the position of Jupiter's four Galilean moons with a variety of…

  11. ESA radiation and micro-meteoroid models applied to Space Weathering of atmosphere-less bodies: icy moons and asteroids

    Science.gov (United States)

    Vallat, Claire; Altobelli, Nicolas; Cornet, Thomas; Schmidt, Jürgen; Navarro, Sara; Erd, Christian; Witasse, Olivier; Rodmann, Jens; Mints, Alexey

    2016-10-01

    al, Dynamics and distribution of Jovian dust ejected from the Galilean satellites, JGR, 2016[2] Dikarev et al., The new ESA meteoroid model, Adv. Space Res., 2005[3] Sicard-Piet et al, JOSE: A new Jovian Specification Environment model, EPSC, 2010

  12. An Adjunct Galilean Satellite Orbiter Using a Small Radioisotope Power Source

    Science.gov (United States)

    Abelson, Robert Dean; Randolph, J.; Alkalai, L.; Collins, D.; Moore, W.

    2005-01-01

    This is a conceptual mission study intended to demonstrate the range of possible missions and applications that could be enabled were a new generation of Small Radioisotope Power Systems to be developed by NASA and DOE. While such systems are currently being considered by NASA and DOE, they do not currently exist. This study is one of several small RPS-enabled mission concepts that were studied and presented in the NASA/JPL document "Enabling Exploration with Small Radioisotope Power Systems" available at: http://solarsystem.nasa.gov/multimedia/download-detail.cfm?DL_ID=82

  13. Iceless Icy Moons: Is the Nice Model In Trouble?

    Science.gov (United States)

    Dones, Henry C. Luke; Levison, H. F.

    2012-05-01

    Nimmo and Korycansky (2012; henceforth NK12) stated that if the outer Solar System underwent a Late Heavy Bombardment (LHB) in the Nice model, the mass striking the icy satellites at speeds up to tens of km/s would have vaporized so much ice that moons such as Mimas, Enceladus, and Miranda would have been devolatilized. NK12's possible explanations of this apparent discrepancy with observations include (1) the mass influx was a factor of 10 less than that in the Nice model; (2) the mass distribution of the impactors was top-heavy, so that luck might have saved some of the moons from suffering large, vapor-removing impacts; or (3) the inner moons formed after the LHB. NK12 calculated the mass influx onto the satellites from the lunar impact rate estimated by Gomes et al. (2005) and scaling factors calculated by Zahnle et al. (1998, 2003; also see Barr and Canup 2010). Production of vapor in hypervelocity impacts is calculated from Kraus et al. (2011). Our preliminary results show that there is about an order-of-magnitude uncertainty in the mass striking the satellites during the LHB, with NK12's estimate at the upper end of the range. We will discuss how the mass influx depends on the velocity and mass distributions of the impactors. The Nice model lives. We thank the NASA Lunar Science Institute (http://lunarscience.nasa.gov/) for support. Barr, A.C., Canup, R.M., Nature Geoscience 3, 164-167 (2010). Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A., Nature 435, 466-469 (2005). Kraus, R.G., Senft, L.E., Stewart, S.T., Icarus 214, 724-738 (2011). Nimmo, F., Korycansky, D.G., Icarus, in press, http://www.sciencedirect.com/science/article/pii/S0019103512000310 (2012). Zahnle, K., Dones, L., Levison, H.F., Icarus 136, 202-222 (1998). Zahnle, K., Schenk, P., Levison, H.F., Dones, L., Icarus 163, 263-289 (2003).

  14. Development of radiative transfer code for JUICE/SWI mission toward the atmosphere of icy moons of Jupiter

    Science.gov (United States)

    Yamada, Takayoshi; Kasai, Yasuko; Yoshida, Naohiro

    2016-07-01

    The Submillimeter Wave Instrument (SWI) is one of the scientific instruments on the JUpiter Icy moon Explorer (JUICE). We plan to observe atmospheric compositions including water vapor and its isotopomers in Galilean moons (Io, Europa, Ganymede, and Callisto). The frequency windows of SWI are 530 to 625 GHz and 1080 to 1275 GHz with 100 kHz spectral resolution. We are developing a radiative transfer code in Japan with line-by-line method for Ganymede atmosphere in THz region (0 - 3 THz). Molecular line parameters (line intensity and partition function) were taken from JPL (Jet Propulsion Laboratory) catalogue. The pencil beam was assumed to calculate a spectrum of H _{2}O and CO in rotational transitions at the THz region. We performed comparisons between our model and ARTS (Atmospheric Radiative Transfer Simulator). The difference were less than 10% and 5% for H _{2}O and CO, respectively, under the condition of the local thermodynamic equilibrium (LTE). Comparison with several models with non-LTE assumption will be presented.

  15. The gravity field of the Saturnian satellites Enceladus and Dione

    Science.gov (United States)

    Iess, L.; Jacobson, R.; Ducci, M.; Stevenson, D. J.; Lunine, J. I.; Armstrong, J. W.; Asmar, S.; Racioppa, P.; Rappaport, N. J.; Tortora, P.

    2012-12-01

    applied to the unconstrained solution, the Radau-Darwin approximation gives a moment of inertia factor (MOIF) that is consistent with a differentiated body and remarkably close to the one predicted by Zharkov et al. [1]. Enceladus' gravity field (inferred from three close flybys on April 28, 2010, November 30, 2010 and May 2, 2012) shows significant departures from a pure quadrupole. Degree-3 harmonics are indeed required to obtain a good fit in a combined solution. However, the quadrupole terms still largely dominate over the higher degree field, as expected for a synchronous rotating body so close to Saturn. Although the J2/C22 ratio is not consistent with the hypothesis of a relaxed shape, the deviations from the hydrostaticity are weak, making the Radau-Darwin approximation still roughly applicable. The inferred MOIF values indicate that Enceladus is a differentiated body. [1] Zharkov, V. N., Leontjev, V. V., Kozenko, A. V., 1985. Models, figures, and gravitational moments of the Galilean satellites of Jupiter and icy satellites of Saturn. Icarus 61, 92-100.

  16. Hidden Galilean symmetry, conservation laws and emergence of spin current in the soliton sector of chiral helimagnet

    Energy Technology Data Exchange (ETDEWEB)

    Bostrem, I.G. [Department of Physics, Ural State University, Ekaterinburg 620083 (Russian Federation); Kishine, J. [Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550 (Japan); Lavrov, R.V. [Department of Physics, Ural State University, Ekaterinburg 620083 (Russian Federation); Ovchinnikov, A.S. [Department of Physics, Ural State University, Ekaterinburg 620083 (Russian Federation)], E-mail: alexander.ovchinnikov@usu.ru

    2009-01-26

    An appearance of the transport spin current in chiral helimagnet is mathematically justified based on the symmetry arguments. Although the starting Lagrangian of the chiral magnet with the Berry phase term and the parity-violating Dzyaloshinskii-Morya coupling is not manifestly Galilean invariant, the Lie point group symmetry analysis and the variational symmetry analysis elucidate the hidden Galilean symmetry and the existence of the linear momentum as a conserved Noether current, respectively.

  17. ICI optical data storage tape: An archival mass storage media

    Science.gov (United States)

    Ruddick, Andrew J.

    1993-01-01

    At the 1991 Conference on Mass Storage Systems and Technologies, ICI Imagedata presented a paper which introduced ICI Optical Data Storage Tape. This paper placed specific emphasis on the media characteristics and initial data was presented which illustrated the archival stability of the media. More exhaustive analysis that was carried out on the chemical stability of the media is covered. Equally important, it also addresses archive management issues associated with, for example, the benefits of reduced rewind requirements to accommodate tape relaxation effects that result from careful tribology control in ICI Optical Tape media. ICI Optical Tape media was designed to meet the most demanding requirements of archival mass storage. It is envisaged that the volumetric data capacity, long term stability and low maintenance characteristics demonstrated will have major benefits in increasing reliability and reducing the costs associated with archival storage of large data volumes.

  18. ICI Alleviation in OFDM System Utilizing Scale Alpha Pulse Shaping

    Directory of Open Access Journals (Sweden)

    Nor Adibah Ibrahim

    2015-05-01

    Full Text Available In this study, a new pulse shaping method namely scale alpha is proposed for mitigating Inter-Carrier Interference (ICI effect in Orthogonal Frequency-Division Multiplexing (OFDM system. The suggested pulse shape is designed and simulated using MATLAB software. Results show that the new pulse shape has lower ICI power and better impulse response performance than Franks, raised cosine and double-jump pulses.

  19. Scale-invariant perturbations from NEC violation: A new variant of Galilean Genesis

    CERN Document Server

    Nishi, Sakine

    2016-01-01

    We propose a novel branch of the Galilean Genesis scenario as an alternative to inflation, in which the universe starts expanding from Minkowski in the asymptotic past with a gross violation of the null energy condition (NEC). This variant, described by several functions and parameters within the Horndeski scalar-tensor theory, shares the same background dynamics with the existing Genesis models, but the nature of primordial quantum fluctuations is quite distinct. In some cases, tensor perturbations grow on superhorizon scales. The tensor power spectrum can be red, blue, and scale invariant, depending on the model, while scalar perturbations are nearly scale invariant. This is in sharp contrast to typical NEC-violating cosmologies, in which a blue tensor tilt is generated. Though the primordial tensor and scalar spectra are both nearly scale invariant as in the inflationary scenario, the consistency relation in our variant of Galilean Genesis is non-standard.

  20. Admissible Mannheim Curves in Pseudo-Galilean Space $G_3^1$

    CERN Document Server

    Akyigit, M; Tosun, M

    2010-01-01

    In this paper, first and second type admissible Mannheim partner curves are defined in pseudo-Galilean space $G_3^1$. Moreover, it is proved that the distance between the reciprocal points of both of first and second type admissible Mannheim curves and the torsions of these curves are constant. Furthermore, the relations for curvatures and torsions of these curves and Schell Theorem are obtained. Finally, a result about these curves being general helix is given.

  1. Mathisson's Spinning Electron Noncommutative Mechanics and Exotic Galilean Symmetry, 66 Years Ago

    CERN Document Server

    Horváthy, P A

    2003-01-01

    The acceleration-dependent system with noncommuting coordinates, proposed by Lukierski, Stichel and Zakrzewski [Ann. Phys. 260 , 224 (1997)] is derived as the non-relativistic limit of Mathisson's classical electron [Acta Phys. Pol. 6 , 218 (1937)], further discussed by Weyssenhoff and Raabe [Acta Phys. Pol. 9 , 7 (1947)]. The two-parameter centrally extended Galilean symmetry of the model is recovered using elementary methods. The relation to Schroedinger's Zitternde Elektron is indicated.

  2. On the Galilean transformation of the few-electron wave functions

    CERN Document Server

    Frolov, Alexei M

    2013-01-01

    The Galilean transformations of the few-electron atomic wave functions are considered. We discuss the few-electron wave functions constructed in the model of independent electrons as well as the truly correlated (or highly accurate) wave functions. Results of our analysis are applied to determine the probability of formation of the negatively charged tritium/protium ions during the nuclear $(n,{}^{3}$He$;t,p)-$reaction of the helium-3 atoms with thermal/slow neutrons.

  3. From Lorentzian to Galilean (2+1) gravity: Drinfel'd doubles, quantisation and noncommutative spacetimes

    CERN Document Server

    Ballesteros, Angel; Naranjo, Pedro

    2014-01-01

    It is shown that the canonical classical $r$-matrix arising from the Drinfel'd double structure underlying the two-fold centrally extended (2+1) Galilean and Newton-Hooke Lie algebras (with either zero or non-zero cosmological constant $\\Lambda$, respectively) originates as a well-defined non-relativistic contraction of a specific class of canonical $r$-matrices associated with the Drinfel'd double structure of the (2+1) (anti)-de Sitter Lie algebra. The full quantum group structure associated with such (2+1) Galilean and Newton-Hooke Drinfel'd doubles is presented, and the corresponding noncommutative spacetimes are shown to contain a commuting 'absolute time' coordinate ${\\hat x}_0$ together with two noncommutative space coordinates $({\\hat x}_1,{\\hat x}_2)$, whose commutator is a function of the cosmological constant $\\Lambda$ and of the (central) 'quantum time' coordinate ${\\hat x}_0$. Thus, the Chern-Simons approach to Galilean (2+1) gravity can be consistently understood as the appropriate non-relativis...

  4. Does asteroid 4 Vesta, with watery 1 Ceres and the Galilean moons, record the Ringwood-mode iron core construction now predicated for Earth and even apply to the other terrestrial planets?

    Science.gov (United States)

    Osmaston, M. F.

    2014-04-01

    -probe tomography. Nature Geoscience 7, 219-223. [8] Pearson DG et al. (2014) Hydrous mantle transition zone indicated by ringwoodite included within diamond. Nature 507, 221-224. [9] Raymond CA et al. (2013) The Crust and Mantle of Vesta's Southern Hemisphere. EPSC Abstracts - 8, EPSC2013-1002. [10] Hutchison R (2004) Meteorites: a petrologic, chemical and isotopic synthesis. CUP. See p.284. [11] Burbine TH et al. (1996) Mantle material in the main belt: battered to bits? Meteorit. Planet. Sci. 31, 607-620. [12] Greenberg R (2005) Europa - the ocean moon: search for an alien biosphere. Springer/Praxis. [13] Kuskov OL et al. (2011) Internal structure of of icy satellites of Jupiter and Saturn and subsurface oceans. Miner. Mag. Goldschmidt 2011, Prague, Abstr. 1257

  5. Ionization chemistry in the H2O-dominant atmospheres of the icy moons

    Science.gov (United States)

    Shematovich, V. I.; Johnson, R. E.

    2007-08-01

    -molecular reaction with H2O. Therefore, the minor O2H+ ion is an important indicator of what is going on in the mixed O2-H2O atmosphere, i.e., at what partition between O2 and H2O in the atmosphere the ionization chemistry results in the major O2+ or H3O+ ion (Johnson et al., 2006 ; Luhmann et al., 2006). The ionization chemistry strongly depends on the sources of parent atmospheric species and, therefore, provides information on the chemical composition of the satellite's icy surface. The inferred networks are used to describe the ionization chemistry in the rarefied atmospheres of the icy satellites in the inner Saturnian magnetosphere. Johnson R.E. Energetic Charged Particles Interaction with Atmospheres and Surfaces. Springer-Verlag, 1990. Johnson R.E. et al. Icarus, v.180, 393-402, 2006. Luhmann J.G. et al. Icarus, v. 181, 465-474, 2006. Shematovich V.I. et al. Icarus, v. 173, 480-498, 2005.

  6. An Impacting Descent Probe for Europa and the Other Galilean Moons of Jupiter

    Science.gov (United States)

    Wurz, P.; Lasi, D.; Thomas, N.; Piazza, D.; Galli, A.; Jutzi, M.; Barabash, S.; Wieser, M.; Magnes, W.; Lammer, H.; Auster, U.; Gurvits, L. I.; Hajdas, W.

    2017-08-01

    We present a study of an impacting descent probe that increases the science return of spacecraft orbiting or passing an atmosphere-less planetary bodies of the solar system, such as the Galilean moons of Jupiter. The descent probe is a carry-on small spacecraft (return to a mission at a low extra level of complexity, engineering effort, and risk. This study builds upon earlier studies for a Callisto Descent Probe for the former Europa-Jupiter System Mission of ESA and NASA, and extends them with a detailed assessment of a descent probe designed to be an additional science payload for the NASA Europa Mission.

  7. An 18 Moments Model for Dense Gases: Entropy and Galilean Relativity Principles without Expansions

    Directory of Open Access Journals (Sweden)

    M. Cristina Carrisi

    2015-01-01

    Full Text Available The 14 moments model for dense gases, introduced in the last few years by Arima, Taniguchi, Ruggeri and Sugiyama, is here extended up to 18 moments. They have found the closure of the balance equations up to a finite order with respect to equilibrium; it is also possible to impose for that model the entropy and Galilean relativity principles up to whatever order with respect to equilibrium, but by using Taylor’s expansion. Here, the exact solution is found, without expansions, but a bigger number of moments has to be considered and reasons will be shown suggesting that this number is at least 18.

  8. IPPF Co-operative Information Service (ICIS). February 1978.

    Science.gov (United States)

    International Planned Parenthood Federation, London (England).

    This publication is a catalogue of document descriptions that may be of use to national family planning/population organizations. The International Planned Parenthood Federation (IPPF) Cooperative Information Service (ICIS) has developed this quarterly series as a service to population documentation centers so that these centers can acquire the…

  9. Neutral atmosphere near the icy surface of Jupiter's moon Ganymede

    Science.gov (United States)

    Shematovich, V. I.

    2016-07-01

    The paper discusses the formation and dynamics of the rarefied gas envelope near the icy surface of Jupiter's moon Ganymede. Being the most massive icy moon, Ganymede can form a rarefied exosphere with a relatively dense near-surface layer. The main parent component of the gas shell is water vapor, which enters the atmosphere due to thermal degassing, nonthermal radiolysis, and other active processes and phenomena on the moon's icy surface. A numerical kinetic simulation is performed to investigate, at the molecular level, the formation, chemical evolution, and dynamics of the mainly H2O- and O2-dominant rarefied gas envelopes. The ionization processes in these rarefied gas envelopes are due to exposure to ultraviolet radiation from the Sun and the magnetospheric plasma. The chemical diversity of the icy moon's gas envelope is attributed to the primary action of ultraviolet solar photons and plasma electrons on the rarefied gas in the H2O- or O2-dominant atmosphere. The model is used to calculate the formation and development of the chemical diversity in the relatively dense near-surface envelope of Ganymede, where an important contribution comes from collisions between parent molecules and the products of their photolysis and radiolysis.

  10. Investigation of the properties of icy lunar polar regolith simulants

    Science.gov (United States)

    Pitcher, Craig; Kömle, Norbert; Leibniz, Otto; Morales-Calderon, Odalys; Gao, Yang; Richter, Lutz

    2016-03-01

    As icy regolith is believed to exist in the subsurface of permanently shadowed areas near the lunar south pole, there is a growing interest in obtaining samples from these polar regions. To qualify for spaceflight, sampling instruments must demonstrate their ability to operate in the expected environment. However, there is currently no quantitative data detailing the extent and distribution of ice in polar regolith. While work has been done to determine the effects of water ice content in simulants such as JSC-1A, to date there has been no investigation into the properties of icy simulants of the regolith believed to be found at lunar polar regions. A series of experiments has therefore been conducted to determine the properties of icy NU-LHT-2M lunar highland simulant, an approximation of lunar polar regolith, at varying degrees of saturation. A number of procedures for preparing the simulant were tested, with the aim of defining a standardised technique for the creation of icy simulants with controlled water contents. Saturation of the highland simulant was found to occur at a water mass content between 13% and 17%, while cone penetration tests demonstrated that a significant increase in penetration resistance occurs at 5 ± 1%. Uniaxial compression tests showed an increase in regolith strength with water mass and density, which slows down as the saturation level is reached. The results presented here demonstrate the first characterisation of the properties of icy lunar polar regolith simulants, which can be expanded upon to further the understanding of its properties for use in future instrumentation testing.

  11. Using Simple Harmonic Motion to Follow the Galilean Moons--Testing Kepler's Third Law on a Small System

    Science.gov (United States)

    de Moraes, I. G.; Pereira, J. A. M.

    2009-01-01

    The motion of the four Galilean moons of Jupiter is studied in this work. The moons had their positions with respect to the centre of the planet measured during one week of observation by means of telescopic charge coupled device images. It is shown that their movement can be well described as a simple harmonic motion. The revolution period and…

  12. Photon-induced electro-chemical processes in airless icy bodies analogues

    Science.gov (United States)

    Marchione, Demian; Gudipati, Murthy

    2016-10-01

    Previous laboratory studies have shown that radiation-induced ionization of impurities in water-rich ices drives the formation of ionized species resulting in charge generation and accumulation in ices [1-3]. It is expected that some of these impurity ions are decomposed into smaller volatile species and ejected into the vacuum. These processes are relevant to the chemical composition of the near-surface tenuous (thin) atmosphere of icy bodies such as the Jovian satellites like Europa.Our work aims at investigating photocurrents from organic impurity embedded water ices of several microns thick and understanding how these measurements correlate with the desorption of volatiles during UV and electron irradiation. These experiments are performed in an ultrahigh vacuum chamber around Europa's surface temperature (100 - 150 K) conditions using a low-pressure hydrogen flow-discharge lamp emitting primarily at Lyα (121.6 nm), a 2 keV electron source, and a substrate-less electrode. Photoionization of organic impurities in the water matrix results in charge pair (electron and ion) separation within the ice, and hence in detectable currents that are measured as a function of the applied bias and the temperature (5 K - 200 K). Photodesorption products are also identified by a quadrupole mass spectrometer (QMS) and correlated with conductivity measurements. We will discuss these results in the context of expected Europa's surface photoconductivity and near-surface volatile production.References:[1] M. S. Gudipati, and L. J. Allamandola, Astrophysical Journal Letters, 2003, 596(2), L195-L198.[2] M. S. Gudipati, Journal of Physical Chemistry A, 2004, 108(20), 4412-4419.[3] S. H. Cuylle, L. J. Allamandola, and H. Linnartz, Astronomy and Astrophysics, 2014, 562, A22.This work has been carried out at Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration, and funded by NASA under Planetary Atmospheres

  13. China's first large tanker for icy area successfully launched

    Institute of Scientific and Technical Information of China (English)

    Chen Jianan

    2006-01-01

    @@ On July 10, the 51800 dwt product/chemical tanker developed, designed and built by China for navigating in icy areas was launched at Guangzhou Shipyard International. The tanker is scheduled for delivery at the end of this year. The second follow-on ship will soon be built on the berths. At present, Guangzhou Shipyard International has a backlog order of 11 such tankers.

  14. A projector formulation of the Galilean covariant Duffin-Kemmer-Petiau field

    Energy Technology Data Exchange (ETDEWEB)

    Santos, E S [Centro Federal de Educacao Tecnologica da Bahia, DCA-Coordenacao de Fisica, Rua Emidio Santos s/n, Barbalho, 40300-010 Salvador, BA (Brazil); Abreu, L M [Centro de Cincias Exatas e Tecnologicas, Universidade Federal do Reconcavo da Bahia, Campus de Cruz das Almas, 44380-000 Cruz das Almas, BA (Brazil)

    2008-02-22

    We construct in this paper a projector formulation of the Galilean covariant Duffin-Kemmer-Petiau field in five dimensions. Such an approach allows us to select the scalar and vector sectors of the theory through the use of the appropriate operators. As an application, we study a non-minimal coupling associated to the DKP harmonic oscillator, naturally in the non-relativistic regime and with the selection of the spin-0 sector in a general representation. We also discuss the local gauge invariance and the anomalous term which appear in the wave equations due to the minimal coupling. In both questions, our results were carried out as in the relativistic case, i.e. the consistent local gauge transformations can be obtained through the choice of the right form of the non-relativistic DKP field.

  15. Galilean and Lorentz Transformations in a Space with Generalized Uncertainty Principle

    Science.gov (United States)

    Tkachuk, V. M.

    2016-12-01

    We consider a space with Generalized Uncertainty Principle (GUP) which can be obtained in the frame of the deformed commutation relations. In the space with GUP we have found transformations relating coordinates and times of moving and rest frames of reference in the first order over the parameter of deformation. In the non-relativistic case we find the deformed Galilean transformation which is rotation in Euclidian space-time. This transformation is similar to the Lorentz one but written for Euclidean space-time where the speed of light is replaced by some velocity related to the parameter of deformation. We show that for relativistic particle in the space with GUP the coordinates of the rest and moving frames of reference satisfy the Lorentz transformation with some effective speed of light.

  16. The Trispectrum in the Effective Theory of Inflation with Galilean symmetry

    CERN Document Server

    Bartolo, Nicola; Fasiello, Matteo

    2013-01-01

    We calculate the trispectrum of curvature perturbations for a model of inflation endowed with Galilean symmetry at the level of the fluctuations around an FRW background. Such a model has been shown to posses desirable properties such as unitarity (up to a certain scale) and non-renormalization of the leading operators, all of which point towards the reasonable assumption that a full theory whose fluctuations reproduce the one here might exist as well as be stable and predictive. The cubic curvature fluctuations of this model produce quite distinct signatures at the level of the bispectrum. Our analysis shows how this holds true at higher order in perturbations. We provide a detailed study of the trispectrum shape-functions in different configurations and a comparison with existent literature. Most notably, predictions markedly differ from their P(X,\\phi) counterpart in the so called equilateral trispectrum configuration. The zoo of inflationary models characterized by somewhat distinctive predictions for hig...

  17. Breaking of Galilean Invariance in the Hydrodynamic Formulation of Ferromagnetic Thin Films

    Science.gov (United States)

    Iacocca, Ezio; Silva, T. J.; Hoefer, Mark A.

    2017-01-01

    Microwave magnetodynamics in ferromagnets are often studied in the small-amplitude or weakly nonlinear regime corresponding to modulations of a well-defined magnetic state. However, strongly nonlinear regimes, where the aforementioned approximations are not applicable, have become experimentally accessible. By reinterpreting the governing Landau-Lifshitz equation of motion, we derive an exact set of equations of dispersive hydrodynamic form that are amenable to analytical study even when full nonlinearity and exchange dispersion are included. The resulting equations are shown to, in general, break Galilean invariance. A magnetic Mach number is obtained as a function of static and moving reference frames. The simplest class of solutions are termed uniform hydrodynamic states (UHSs), which exhibit fluidlike behavior including laminar flow at subsonic speeds and the formation of a Mach cone and wave fronts at supersonic speeds. A regime of modulational instability is also possible, where the UHS is violently unstable. The hydrodynamic interpretation opens up novel possibilities in magnetic research.

  18. Issues associated with Galilean invariance on a moving solid boundary in the lattice Boltzmann method.

    Science.gov (United States)

    Peng, Cheng; Geneva, Nicholas; Guo, Zhaoli; Wang, Lian-Ping

    2017-01-01

    In lattice Boltzmann simulations involving moving solid boundaries, the momentum exchange between the solid and fluid phases was recently found to be not fully consistent with the principle of local Galilean invariance (GI) when the bounce-back schemes (BBS) and the momentum exchange method (MEM) are used. In the past, this inconsistency was resolved by introducing modified MEM schemes so that the overall moving-boundary algorithm could be more consistent with GI. However, in this paper we argue that the true origin of this violation of Galilean invariance (VGI) in the presence of a moving solid-fluid interface is due to the BBS itself, as the VGI error not only exists in the hydrodynamic force acting on the solid phase, but also in the boundary force exerted on the fluid phase, according to Newton's Third Law. The latter, however, has so far gone unnoticed in previously proposed modified MEM schemes. Based on this argument, we conclude that the previous modifications to the momentum exchange method are incomplete solutions to the VGI error in the lattice Boltzmann method (LBM). An implicit remedy to the VGI error in the LBM and its limitation is then revealed. To address the VGI error for a case when this implicit remedy does not exist, a bounce-back scheme based on coordinate transformation is proposed. Numerical tests in both laminar and turbulent flows show that the proposed scheme can effectively eliminate the errors associated with the usual bounce-back implementations on a no-slip solid boundary, and it can maintain an accurate momentum exchange calculation with minimal computational overhead.

  19. Laboratory test of the Galilean universality of the free fall experiment

    Science.gov (United States)

    Christensen, Rasmus S.; Teiwes, Ricky; Petersen, Steffen V.; Uggerhøj, Ulrik I.; Jacoby, Bo

    2014-03-01

    There is a popular myth that Galileo dropped two objects of the same shape but different mass, noted their equal fall time, and concluded that gravitational motion is independent of the mass of the object. This paper demonstrates that this experiment—if actually performed—most likely would have yielded a different result and thus with modern eyes led to a different conclusion. The paper consists of two parts: (1) a theoretical description with a numerical and an analytical solution of the problem, and (2) an experiment of the Galilean type that provides experimental evidence within 1% accuracy that the theory applies. Previous papers on this subject have been almost exclusively theoretical and/or calculational, and we emphasize the suitability of the performed experiment as an affordable instructional exercise, e.g. for undergraduates. We find a difference in impact time of 0.109 s for otherwise nearly identical objects of masses differing by about a factor of 3, mlight = 57.52 g and mheavy = 173.62 g, dropped from a height of 23.192 m, about half of the height of the Leaning Tower of Pisa. Very convincing agreement between experiment and theory, including an account of the fluid dynamics in air, is achieved. By use of the theory thus corroborated, the calculated difference in height at first impact corresponding to the Galilean case is about 5.8 m (assuming a lead ball and an ebony ball, each the size of a tennis ball), easily detectable both visually and, with a difference in impact time of about 0.22 s, aurally. The time difference is also sufficiently large to be unlikely to be caused by inaccuracy in release time. This gives an indication that if Galileo did actually perform the experiment, he may have chosen to neglect small differences (≃10%) in impact times observed using large differences (factor ≃ 10) in mass.

  20. Thermal Conductive Heat Transfer and Partial Melting of Volatiles in Icy Moons, Asteroids, and Kuiper Belt Objects (Invited)

    Science.gov (United States)

    Kargel, J. S.; Furfaro, R.

    2013-12-01

    Thermal gradients within conductive layers of icy satellite and asteroids depend partly on heat flow, which is related to the secular decay of radioactive isotopes, to heat released by chemical phase changes, by conversion of gravitational potential energy to heat during differentiation, tidal energy dissipation, and to release of heat stored from prior periods. Thermal gradients are also dependent on the thermal conductivity of materials, which in turn depends on their composition, crystallinity, porosity, crystal fabric anisotropy, and details of their mixture with other materials. Small impurities can produce lattice defects and changes in polymerization, and thereby have a huge influence on thermal conductivity, as can cage-inclusion (clathrate) compounds. Heat flow and thermal gradients can be affected by fluid phase advection of mass and heat (in oceans or sublimating upper crusts), by refraction related to heterogeneities of thermal conductivity due to lateral variations and composition or porosity. Thermal profiles depend also on the surface temperature controlled by albedo and climate, surface relief, and latitude, orbital obliquity and surface insolation, solid state greenhouses, and endogenic heating of the surface. The thermal state of icy moon interiors and thermal gradients can be limited at depth by fluid phase advection of heat (e.g., percolating meteoric methane or gas emission), by the latent heat of phase transitions (melting, solid-state transitions, and sublimation), by solid-state convective or diapiric heat transfer, and by foundering. Rapid burial of thick volatile deposits can also affect thermal gradients. For geologically inactive or simple icy objects, most of these controls on heat flow and thermal gradients are irrelevant, but for many other icy objects they can be important, in some cases causing large lateral and depth variations in thermal gradients, large variations in heat flow, and dynamically evolving thermal states. Many of

  1. Surface Penetrating Radar Simulations for Jupiter's Icy Moons

    Science.gov (United States)

    Markus, Thorsten; Gogineni, S. P.; Green, J. L.; Reinisch, B. W.; Song, P.; Fung, S. F.; Benson, R. F.; Taylor, W. W. L.; Cooper, F.

    2003-01-01

    The icy moons of Jupiter (Europa, Callisto, and Ganymede) are of similar overall composition but show different surface features as a result of different sub-surface processes. Furthermore, each of these moons could have a liquid ocean of water buried underneath the icy crust, but their depth can only be speculated. For Europa, estimates put the thickness of the ice shell anywhere between 2-30 km, with'a few models predicting up to 100 km. Much of the uncertainties are due to the largely unknown temperature gradients and levels of water impurities across different surface layers. One of the most important geological processes is the possible transportation of heat by ice convection. If the ice is convecting, then an upper limit of about 20 km is set for the depth of the ocean underneath. Convection leads to a sharp increase in temperature followed by a thick region of nearly constant temperature. If ice is not convecting, then an exponentially increasing temperature profile is expected. The crust is thought to be a mixture of ice and rock, and although the exact percentage of rock is not known, it is expected to be low. Additionally, the ice crust could contain salt, similar to sea ice on Earth. The exact amount of salt and how that amount changes with depth is also unknown. In preparation for the Jupiter Icy Moons Orbiter (JIMO) mission, we performed simulations for a surface-penetrating radar investigating signatures for different possible surface and sub-surface structures of these moons in order to estimate the applicability of using radar with a frequency range between 1 and 50 MHz. This includes simulations of power requirements, attenuation losses, layer resolutions for scenarios with and without the presence of a liquid ocean underneath the ice, cases of convecting and non-convecting ice, different impurities within the ice, and different surface roughnesses.

  2. A Passive Probe for Subsurface Oceans and Liquid Water in Jupiter's Icy Moons

    OpenAIRE

    Romero-Wolf, Andrew; Vance, Steve; Maiwald, Frank; Heggy, Essam; Ries, Paul; Liewer, Kurt

    2014-01-01

    We describe an interferometric reflectometer method for passive detection of subsurface oceans and liquid water in Jovian icy moons using Jupiter's decametric radio emission (DAM). The DAM flux density exceeds 3,000 times the galactic background in the neighborhood of the Jovian icy moons, providing a signal that could be used for passive radio sounding. An instrument located between the icy moon and Jupiter could sample the DAM emission along with its echoes reflected in the ice layer of the...

  3. An excess of pedestrian injuries in icy conditions

    DEFF Research Database (Denmark)

    Merrild, Ulrik; Bak, Soeren

    1983-01-01

    An "icy condition epidemic" has been analyzed in an investigation of patients treated in the casualty department of Odense University Hospital: it was found that the victims were mainly comprised of pedestrians and that the pedestrians had 14 times more injuries than during a normal winter period...... clearing of the snow, and (3) spreading of sand, and possibly salt, on footpaths and bicycle paths. Specific measures should be launched to help the elderly during such periods, in order that outdoor activities may be cut to a minimum. © 1983....

  4. Thermo-chemical Ice Penetrator for Icy Moons

    Science.gov (United States)

    Arenberg, J. W.; Lee, G.; Harpole, G.; Zamel, J.; Sen, B.; Ross, F.; Retherford, K. D.

    2016-12-01

    The ability to place sensors or to take samples below the ice surface enables a wide variety of potential scientific investigations. Penetrating an ice cap can be accomplished via a mechanical drill, laser drill, kinetic impactor, or heated penetrator. This poster reports on the development of technology for the latter most option, namely a self-heated probe driven by an exothermic chemical reaction: a Thermo-chemical ice penetrator (TChIP). Our penetrator design employs a eutectic mix of alkali metals that produce an exothermic reaction upon contact with an icy surface. This reaction increases once the ice starts melting, so no external power is required. This technology is inspired by a classified Cold-War era program developed at Northrop Grumman for the US Navy. Terrestrial demonstration of this technology took place in the Arctic; however, this device cannot be considered high TRL for application at the icy moons of the solar system due to the environmental differences between Earth's Arctic and the icy moons. These differences demand a TChIP design specific to these cold, low mass, airless worlds. It is expected that this model of TChIP performance will be complex, incorporating all of the forces on the penetrator, gravity, the thermo-chemistry at the interface between penetrator and ice, and multi-phase heat and mass transport, and hydrodynamics. Our initial efforts are aimed at the development of a validated set of tools and simulations to predict the performance of the penetrator for both the environment found on these icy moons and for a terrestrial environment. The purpose of the inclusion of the terrestrial environment is to aid in model validation. Once developed and validated, our models will allow us to design penetrators for a specific scientific application on a specific body. This poster discusses the range of scientific investigations that are enabled by TChIP. We also introduce the development plan to advance TChIP to the point where it can be

  5. The Jupitor icy moons orbiter project: The scientific rationale

    Science.gov (United States)

    Creely, Ronald; Johnson, Torrence

    The Jupiter Icy Moons Orbiter (JIMO) is proposed by NASA as the next step in the exploration of the Jovian system following the successful Galileo project. JIMO would use nuclear-electric propulsion to deliver a highly capable scientific payload to Jupiter and go into orbit around Europa, Ganymede, and Callisto, and to conduct investigations of the Jovian system. In early 2003, a NASA Science Definition Team (SDT) was appointed to develop the scientific rationale and priorities for JIMO. The SDT, co-chaired by T. Johnson and R. Greeley, consisted of 38 scientists representing the broad scientific potential afforded by JIMO.This article summarizes the principal findings of the SDT.

  6. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  7. From Lorentzian to Galilean (2+1) gravity: Drinfelʼd doubles, quantization and noncommutative spacetimes

    Science.gov (United States)

    Ballesteros, Ángel; Herranz, Francisco J.; Naranjo, Pedro

    2014-12-01

    It is shown that the canonical classical r-matrix arising from the Drinfel'd double (DD) structure underlying the two-fold centrally extended (2+1) Galilean and Newton-Hooke (NH) Lie algebras (with either zero or non-zero cosmological constant Λ, respectively) originates as a well-defined non-relativistic contraction of a specific class of canonical r-matrices associated with the DD structure of the (2+1) (anti)-de Sitter Lie algebra. The full quantum group structure associated with such (2+1) Galilean and NH DD is presented, and the corresponding noncommutative spacetimes are shown to contain a commuting ‘absolute time’ coordinate {{\\hat{x}}0} together with two noncommutative space coordinates ({{\\hat{x}}1},{{\\hat{x}}2}), whose commutator is a function of the cosmological constant Λ and of the (central) ‘quantum time’ coordinate {{\\hat{x}}0}. Thus, the Chern-Simons approach to Galilean (2+1) gravity can be consistently understood as the appropriate non-relativistic limit of the Lorentzian theory, and their associated quantum group symmetries (which do not fall into the family of so-called kappa-deformations) can also be derived from the (anti)-de Sitter quantum doubles through a well-defined quantum group contraction procedure.

  8. Complex prebiotic chemistry within a simple impacting icy mixture

    Science.gov (United States)

    Goldman, Nir

    2013-06-01

    We present results of prebiotic molecule synthesis in shock compressed mixtures of simple ices from quantum molecular dynamics (MD) simulations. Given the likelihood of a CO2-rich primitive atmosphere, it is possible that impact processes of comets or other icy bodies were partially responsible for the creation of prebiotic chemical compounds on early Earth. We have conducted simulations of the chemical reactivity within an oxidized astrophysical icy mixture to close to equilibrium using a density functional tight binding (DFTB) approach. We observe that moderate shock pressures and temperatures (35 GPa and 2800 K) produce a number of functionalized polycyclic aromatic hydrocarbons (PAHs), which remain intact upon expansion and cooling to lower conditions. At higher shock pressures and temperatures (48-62 GPa, 3700-4700 K), we observe the synthesis of a variety of short-lived, exotic C--C and C--N bonded oligomers which decompose upon expansion and cooling to form precursors to amino acids and other prebiotic compounds, such as long chain alkanes, HCN, CH4 and formaldehyde. Our results provide a mechanism for shock synthesis of prebiotic molecules at realistic impact conditions that is independent of external features such as the presence of a catalyst, illuminating UV radiation, or pre-existing conditions on a planet. This work was performed at LLNL under Contract DE-AC52-07NA27344, and was funded by the NASA Astrobiology program.

  9. BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, B.; Mukherjee, R.; Subramanian, K. P.; Banerjee, S. B., E-mail: bhala@prl.res.in [Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad (India)

    2015-01-10

    Propargyl alcohol (CHCCH{sub 2}OH) is a known stable isomer of the propenal (CH{sub 2}CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm{sup –1}. Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C{sub 6}H{sub 6}) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C{sub 3}H{sub 3}) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C{sub 6}H{sub 6} in the interstellar icy mantles.

  10. Stabilization of ammonia-rich hydrate inside icy planets.

    Science.gov (United States)

    Naden Robinson, Victor; Wang, Yanchao; Ma, Yanming; Hermann, Andreas

    2017-08-22

    The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets-as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H2O)(NH3)2, is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O(2-)([Formula: see text])2, where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia-water mixture. This suggests it precipitates out of any ammonia-water mixture at sufficiently high pressures and thus forms an important component of icy planets.

  11. Near-infrared Brightness of the Galilean Satellites Eclipsed in Jovian Shadow: A New Technique to Investigate Jovian Upper Atmosphere

    CERN Document Server

    Tsumura, K; Egami, E; Hayano, Y; Honda, C; Kimura, J; Kuramoto, K; Matsuura, S; Minowa, Y; Nakajima, K; Nakamoto, T; Shirahata, M; Surace, J; Takahashi, Y; Wada, T

    2014-01-01

    We have discovered that Europa, Ganymede and Callisto are bright around 1.5 {\\mu}m even when not directly lit by sunlight, based on observations from the Hubble Space Telescope and the Subaru Telescope. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was $10^{-6}$-$10^{-7}$ of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 {\\mu}m, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 {\\mu}m by the Spitzer Space Telescope but it was not detected, suggesting a significant wavelength dependence. The reason why they are luminous even when in the Jovian shadow is still unknown, but forward-scattered sunlight by haze in the Jovian upper atmosphere is proposed as the most pla...

  12. Emergence of Habitable Environments in Icy World Interiors

    Science.gov (United States)

    Neveu, Marc

    2016-07-01

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life [1]. Such environments include hydrothermal systems, spatially confined systems where hot aqueous fluid circulates through rock by convection. Hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are icy moons and dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core [2]. By improving an icy world evolution code [3] to include the effects of core fracturing and hydrothermal circulation, I show that several icy moons and dwarf planets likely have undergone extensive water-rock interaction [4,5]. This supports observations of aqueous products on their surfaces [6,7]. I simulated the alteration of chondritic rock [8] by pure water or fluid of cometary composition [9] to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the distribution of radionuclides, whose decay is a chief heat source on dwarf planets [10]. Hydrothermal circulation also efficiently transports heat from the core into the ocean, thereby increasing ocean persistence [4]. Thus, these coupled geophysical-geochemical models provide a comprehensive picture of icy world evolution and the emergence of liquid environments in chemical disequilibrium with underlying rock in their interiors. Habitable settings also require a suitable supply of bioessential elements; but what constitutes "suitable"? I sought to quantify the bulk elemental composition of hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA. To do so, one must minimize the contribution of non-biological material to the samples analyzed. This was achieved using a

  13. Crustal control of dissipative ocean tides in Enceladus and other icy moons

    CERN Document Server

    Beuthe, Mikael

    2016-01-01

    Could tidal dissipation within Enceladus' subsurface ocean account for the observed heat flow? Earthlike models of dynamical tides give no definitive answer because they neglect the influence of the crust. I propose here the first model of dissipative tides in a subsurface ocean, by combining the Laplace Tidal Equations with the membrane approach. For the first time, it is possible to compute tidal dissipation rates within the crust, ocean, and mantle in one go. I show that oceanic dissipation is strongly reduced by the crustal constraint, and thus contributes little to Enceladus' present heat budget. Tidal resonances could have played a role in a forming or freezing ocean less than 100 m deep. The model is general: it applies to all icy satellites with a thin crust and a shallow ocean. Scaling rules relate the resonances and dissipation rate of a subsurface ocean to the ones of a surface ocean. If the ocean has low viscosity, the westward obliquity tide does not move the crust. Therefore, crustal dissipation...

  14. An Impacting Descent Probe for Europa and the Other Galilean Moons of Jupiter

    Science.gov (United States)

    Wurz, P.; Lasi, D.; Thomas, N.; Piazza, D.; Galli, A.; Jutzi, M.; Barabash, S.; Wieser, M.; Magnes, W.; Lammer, H.; Auster, U.; Gurvits, L. I.; Hajdas, W.

    2017-08-01

    We present a study of an impacting descent probe that increases the science return of spacecraft orbiting or passing an atmosphere-less planetary bodies of the solar system, such as the Galilean moons of Jupiter. The descent probe is a carry-on small spacecraft (fast ( km/s) descent to the surface until impact. The science goals and the concept of operation are discussed with particular reference to Europa, including options for flying through water plumes and after-impact retrieval of very-low altitude science data. All in all, it is demonstrated how the descent probe has the potential to provide a high science return to a mission at a low extra level of complexity, engineering effort, and risk. This study builds upon earlier studies for a Callisto Descent Probe for the former Europa-Jupiter System Mission of ESA and NASA, and extends them with a detailed assessment of a descent probe designed to be an additional science payload for the NASA Europa Mission.

  15. Stable boosted-frame simulations of laser-wakefield acceleration using Galilean coordinates

    Science.gov (United States)

    Lehe, Remi; Kirchen, Manuel; Godfrey, Brendan; Maier, Andreas; Vay, Jean-Luc

    2016-10-01

    While Particle-In-Cell (PIC) simulations of laser-wakefield acceleration are typically very computationally expensive, it is well-known that representing the system in a well-chosen Lorentz frame can reduce the computational cost by orders of magnitude. One of the limitation of this ``boosted-frame'' technique is the Numerical Cherenkov Instability (NCI) - a numerical instability that rapidly grows in the boosted frame and must be eliminated in order to obtain valid physical results. Several methods have been proposed in order to eliminate the NCI, but they introduce additional numerical corrections (e.g. heavy smoothing, unphysical modification of the dispersion relation, etc.) which could potentially alter the physics. By contrast, here we show that, for boosted-frame simulations of laser-wakefield acceleration, the NCI can be eliminated simply by integrating the PIC equations in Galilean coordinates (a.k.a comoving coordinates), without additional numerical correction. Using this technique, we show excellent agreement between simulations in the laboratory frame and Lorentz-boosted frame, with more than 2 orders of magnitude speedup in the latter case. Work supported by US-DOE Contracts DE-AC02-05CH11231.

  16. Interpreting the parables of the Galilean Jesus: A social-scientific approach

    Directory of Open Access Journals (Sweden)

    Ernest van Eck

    2009-09-01

    Full Text Available This article proposes a methodology for interpreting the parables of Jesus. The methodology put forward has as starting point two convictions. Firstly, the difference between the context of Jesus’ parables as told by Jesus the Galilean in 30 CE and the literary context of the parables in the gospels has to be taken seriously. Secondly, an effort has to be made to at least try to avoid the fallacies of ethnocentrism and anachronism when interpreting the parables. In an effort to achieve this goal it is argued that social-scientific criticism presents itself as the obvious line of approach. Operating from these two convictions, the method being proposed is explained by using 12 statements (or theses which are discussed as concisely and comprehensively as possible. It is inter alia argued that the central theme of Jesus’ parables was the non-apocalyptic kingdom of God, that the parables are atypical stories (comparisons, and that the parables depict Jesus as a social prophet.

  17. Relativity, symmetry and the structure of quantum theory I Galilean quantum theory

    CERN Document Server

    Klink, William H

    2015-01-01

    Quantum theory is one of the most successful of all physical theories. Our everyday world is dominated by devices that function because of knowledge of the quantum world. Yet many, physicists and non-physicists alike, find the theory which explains the behavior of the quantum world baffling and strange. This book is the first in a series of three that argues that relativity and symmetry determine the structure of quantum theory. That is to say, the structure of quantum theory is what it is because of relativity and symmetry. There are different types of relativity, each leading to a particular type of quantum theory. This book deals specifically with what we call Newton relativity, the form of relativity built into Newtonian mechanics, and the quantum theory to which it gives rise, which we call Galilean (often misleadingly called non-relativistic) quantum theory. Key Features: • Meaning and significance of the term of relativity; discussion of the principle of relativity. • Relation of symmetry to relati...

  18. Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

    Science.gov (United States)

    Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J.-L.; Bruzzone, L.; Kofman, W.

    2012-02-01

    Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5 and 50 MHz. Part of this frequency range overlaps with that of the natural jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emissions are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

  19. JUICE: A European Mission to Jupiter and its Icy Moons

    Science.gov (United States)

    Grasset, Olivier; Witasse, Olivier; Barabash, Stas; Brandt, Pontus; Bruzzone, Lorenzo; Bunce, Emma; Cecconi, Baptiste; Cavalié, Thibault; Cimo, Giuseppe; Coustenis, Athena; Cremonese, Gabriele; Dougherty, Michele; Fletcher, Leigh N.; Gladstone, Randy; Gurvits, Leonid; Hartogh, Paul; Hoffmann, Holger; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Kasaba, Yasumasa; Kaspi, Yohai; Krupp, Norbert; Langevin, Yves; Mueller-Wodarg, Ingo; Palumbo, Pasquale; Piccioni, Giuseppe; Plaut, Jeffrey; Poulet, Francois; Roatsch, Thomas; Retherford, Kurt D.; Rothkaehl, Hanna; Stevenson, David J.; Tosi, Federico; Van Hoolst, Tim; Wahlund, Jan-Erik; Wurz, Peter; Altobelli, Nicolas; Accomazzo, A.; Boutonnet, Arnaud; Erd, Christian; Vallat, Claire

    2016-10-01

    JUICE - JUpiter ICy moons Explorer - is the first large mission in the ESA Cosmic Vision programme [1]. The implementation phase started in July 2015. JUICE will arrive at Jupiter in October 2029, and will spend 3 years characterizing the Jovian system, the planet itself, its giant magnetosphere, and the giant icy moons: Ganymede, Callisto and Europa. JUICE will then orbit Ganymede.The first goal of JUICE is to explore the habitable zone around Jupiter [2]. Ganymede is a high-priority target because it provides a unique laboratory for analyzing the nature, evolution and habitability of icy worlds, including the characteristics of subsurface oceans, and because it possesses unique magnetic fields and plasma interactions with the environment. On Europa, the focus will be on recently active zones, where the composition, surface and subsurface features (including putative water reservoirs) will be characterized. Callisto will be explored as a witness of the early Solar System.JUICE will also explore the Jupiter system as an archetype of gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere and ionosphere. JUICE will investigate the 3D properties of the magnetodisc, and study the coupling processes within the magnetosphere, ionosphere and thermosphere. The mission also focuses on characterizing the processes that influence surface and space environments of the moons.The payload consists of 10 instruments plus a ground-based experiment (PRIDE) to better constrain the S/C position. A remote sensing package includes imaging (JANUS) and spectral-imaging capabilities from UV to sub-mm wavelengths (UVS, MAJIS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the moons, and a radio science experiment (3GM) to probe the atmospheres and to determine the gravity fields. The in situ package comprises a suite to study plasma and

  20. Polymerization of building blocks of life on Europa and other icy moons

    CERN Document Server

    Kimura, Jun

    2015-01-01

    The outer solar system may provide a potential habitat for extraterrestrial life. Remote sensing data from the Galileo spacecraft suggest that the jovian icy moons, Europa, Ganymede, and possibly Callisto, may harbor liquid water oceans underneath their icy crusts. Although compositional information required for the discussion of habitability is limited because of significantly restricted observation data, organic molecules are ubiquitous in the universe. Recently, in-situ spacecraft measurements and experiments suggest that amino acids can be formed abiotically on interstellar ices and comets. These amino acids could be continuously delivered by meteorite or comet impacts to icy moons. Here, we show that polymerization of organic monomers, in particular amino acids and nucleotides, could proceed spontaneously in the cold environment of icy moons, in particular the Jovian icy moon Europa as a typical example, based on thermodynamic calculations, though kinetics of formation are not addressed. Observed surface...

  1. Thermo-Chemical Convection in Europa's Icy Shell with Salinity

    Science.gov (United States)

    Han, L.; Showman, A. P.

    2005-01-01

    Europa's icy surface displays numerous pits, uplifts, and chaos terrains that have been suggested to result from solid-state thermal convection in the ice shell, perhaps aided by partial melting. However, numerical simulations of thermal convection show that plumes have insufficient buoyancy to produce surface deformation. Here we present numerical simulations of thermochemical convection to test the hypothesis that convection with salinity can produce Europa's pits and domes. Our simulations show that domes (200-300 m) and pits (300-400 m) comparable to the observations can be produced in an ice shell of 15 km thick with 5-10% compositional density variation if the maximum viscosity is less than 10(exp 18) Pa sec. Additional information is included in the original extended abstract.

  2. Digging Into the Surface of the Icy Dwarf Planet Eris

    CERN Document Server

    Abernathy, M R; Grundy, W M; Licandro, J; Romanishin, W; Cornelison, D; Vilas, F

    2008-01-01

    We describe optical spectroscopic observations of the icy dwarf planet Eris with the 6.5 meter MMT telescope and the Red Channel Spectrograph. We report a correlation, that is at the edge of statistical significance, between blue shift and albedo at maximum absorption for five methane ice bands. We interpret the correlation as an increasing dilution of methane ice with another ice component, probably nitrogen, with increasing depth into the surface. We suggest a mechanism to explain the apparent increase in nitrogen with depth. Specifically, if we are seeing Eris 50 degrees from pole-on (Brown and Schaller, 2008), the pole we are seeing now at aphelion was in winter darkness at perihelion. Near perihelion, sublimation could have built up atmospheric pressure on the sunlit (summer) hemisphere sufficient to drive winds toward the dark (winter) hemisphere, where the winds would condense. Because nitrogen is more volatile and scarcer than methane, it sublimated from the sunlit hemisphere relatively early in the s...

  3. Fantastic Icy Worlds and Where to Find Them

    Science.gov (United States)

    Bannister, Michele T.

    2017-06-01

    The outer Solar System has a wealth of recent discoveries that inform our understanding of orbital dynamics and provoke exciting new questions. The populations of small icy worlds orbiting in the vast volume beyond Neptune are remarkably abundant. Observational surveys including the Outer Solar System Origins Survey are revealing an intricate filigree of mean-motion resonant orbits, emplaced by the historic migration of Neptune. There are also new discoveries of rare trans-Neptunian objects that orbit even further afield, so far from planetary and Galactic tide influences that they are not thought to be produced in the current known planetary architecture of the Solar System. These have informed the recent debate on the existence of a distant giant planet. The hard-to-observe extreme TNOs require a formation method - and offer tantalizing hints that our Solar System is more complex than our current conception.

  4. A Holographic Microscope for Detection of Microorganisms on Icy Worlds

    Science.gov (United States)

    Lindensmith, C. A.; Nadeau, J. L.; Deming, J. W.; Showalter, G. M.; Rider, S.; Bedrossian, M.

    2015-12-01

    Holography is a well-established imaging technique that uses the interference of light to record and reproduce three-dimensional images of objects. Its use began in the 1960s with the invention of the laser. Digital holographic microscopy (DHM) has several advantages over ordinary imaging microscopy which make it ideal for field and astrobiology use, including no need for focus or scanning so that instruments are readily made autonomous. DHM can produce simultaneous bright-field and quantitative phase-contrast images of the same field, providing additional information about transparent objects, e.g., refractive index and/or thickness; thus it inherently supports effective label-free imaging. We have built a fieldable DHM for detection of microorganisms in bodies of water and in brines collected from sea ice. Ice that appears solid to the eye contains interconnected brine-filled microscopic pores and veins which are occupied by populations of prokaryotes and eukaryotes. The presence of life in "solid" ice has important implications for exploration of icy worlds, where it is unlikely that the first missions will be able to access the subsurface oceans. Using this new instrument, we examined several dozen samples from three different sites around Nuuk, Greenland. In all samples, mixed populations of both prokaryotic and eukaryotic microorganisms were observed. Many of the organisms were motile immediately upon extraction from sea ice, and others became motile after warming or addition of sugars and/or amino acids. Meaningful motility was readily distinguished from turbulence or fluid flow. The spatial resolution of the instrument was better than 1 μm, leading to unambiguous recognition of subcellular structures in eukaryotes, including nuclei and chloroplasts. We present mission scenrios for both orbiters and landers in which DHM may be used as a valuable complement to chemical-based life detection techniques for discovery of cellular life on icy worlds.

  5. High energy electron sintering of icy regoliths: Formation of the PacMan thermal anomalies on the icy Saturnian moons

    Science.gov (United States)

    Schaible, M. J.; Johnson, R. E.; Zhigilei, L. V.; Piqueux, S.

    2017-03-01

    The so-called 'PacMan' features on the leading hemispheres of the icy Saturnian moons of Mimas, Tethys and Dione were initially identified as anomalous optical discolorations and subsequently shown to have greater thermal inertia than the surrounding regions. The shape of these regions matches calculated deposition contours of high energy plasma electrons moving opposite to the moon's orbital direction, thus suggesting that electron interactions with the grains produce the observed anomalies. Here, descriptions of radiation-induced diffusion processes are given, and various sintering models are considered to calculate the rate of increase in the contact volume between grains in an icy regolith. Estimates of the characteristic sintering timescale, i.e. the time necessary for the thermal inertia to increase from that measured outside the anomalous regions to that within, are given for each of the moons. Since interplanetary dust particle (IDP) impact gardening and E-ring grain infall would be expected to mix the regolith and obscure the effects of high energy electrons, sintering rates are compared to rough estimates of the impact-induced resurfacing rates. Estimates of the sintering timescale determined by extrapolating laboratory measurements are below ∼0.03 Myr, while the regolith renewal timescales are larger than ∼0.1 Myr, thus indicating that irradiation by the high energy electrons should be sufficient to form stable thermal anomalies. More detailed models developed for sintering of spherical grains are able to account for the radiation-induced anomalies on Mimas and Tethys only if the regoliths on those bodies are relatively compact and composed of small (≲ 5 μm) grains or grain aggregates, and/or the grains are highly non-spherical with surface defect densities in the inter-grain contact regions that are much higher than expected for crystalline water ice grains at thermal equilibrium. These results are consistent with regolith thermal conductivity

  6. Artificial Crater Formation on Satellite Surfaces Using an Orbiting Railgun

    Science.gov (United States)

    Dissly, R. W.; Miller, K. L.; Carlson, R. J.

    2003-01-01

    The specification of greater than 45kW of disposable power available on the JIMO spacecraft raises the possibility of a new class of instrumentation that has utility at such power levels. In this presentation we discuss the concept of an electromagnetic mass driver that can launch projectiles from orbit around one of the Galilean satellites directed on a trajectory that will impact the satellite surface. The resulting impact will create a crater that will provide information on the mechanical properties of surface and near-surface materials, expose subsurface materials for remote spectral identification, and form a vapor cloud that can be sensed for composition either remotely or in-situ. An analog for such a controlled cratering experiment is Deep Impact, a mission to observe the crater and ensuing ejecta cloud formed by a ballistic projectile into a comet surface in July, 2005.

  7. Artificial Crater Formation on Satellite Surfaces Using an Orbiting Railgun

    Science.gov (United States)

    Dissly, R. W.; Miller, K. L.; Carlson, R. J.

    2003-01-01

    The specification of greater than 45kW of disposable power available on the JIMO spacecraft raises the possibility of a new class of instrumentation that has utility at such power levels. In this presentation we discuss the concept of an electromagnetic mass driver that can launch projectiles from orbit around one of the Galilean satellites directed on a trajectory that will impact the satellite surface. The resulting impact will create a crater that will provide information on the mechanical properties of surface and near-surface materials, expose subsurface materials for remote spectral identification, and form a vapor cloud that can be sensed for composition either remotely or in-situ. An analog for such a controlled cratering experiment is Deep Impact, a mission to observe the crater and ensuing ejecta cloud formed by a ballistic projectile into a comet surface in July, 2005.

  8. Gravimetry, Relativity, and the Global Navigation Satellite Systems

    CERN Document Server

    Tarantola, Albert; Pozo, Jose Maria; Coll, Bartolome

    2009-01-01

    Relativity is an integral part of positioning systems, and this is taken into account in today's practice by applying many "relativistic corrections" to computations performed using concepts borrowed from Galilean physics. A different, fully relativistic paradigm can be developed for operating a positioning system. This implies some fundamental changes. For instance, the basic coordinates are four times (with a symmetric meaning, not three space coordinate and one time coordinate) and the satellites must have cross-link capabilities. Gravitation must, of course, be taken into account, but not using the Newtonian theory: the gravitation field is, and only is, the space-time metric. This implies that the positioning problem and the gravimetry problem can not be separated. An optimization theory can be developed that, because it is fully relativistic, does not contain any "relativistic correction". We suggest that all positioning satellite systems should be operated in this way. The first benefit of doing so wou...

  9. The compression behavior of blödite at low and high temperature up to ~10GPa: Implications for the stability of hydrous sulfates on icy planetary bodies

    Energy Technology Data Exchange (ETDEWEB)

    Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra; Fei, Yingwei; Prakapenka, Vitali

    2017-03-01

    Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ~10.4 GPa and temperatures from ~118.8 K to ~490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperature equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede. The experimentally determined volume expansivity, α, varies from 7.6 (7) 10-5 K-1 at 0.0001 GPa (from 118.8 to 413.15 K) to 2.6 (3) 10-5 K-1 at 10 GPa (from 313.0 to 453.0 K) with a δα/δP coefficient = -5.6(9)10-6 GPa-1 K-1. The bulk modulus calculated from the least squares fitting of P-V data on the isotherm at 413 K using a second-order Birch - Murnaghan equation of state is 38(5) GPa, which gives the value of δK/δT equal to 0.01(5) GPa K-1. The thermo-baric behavior of blödite appears strongly anisotropic with c lattice parameter being more deformed with respect to a and b. Thermogravimetric analyses performed at ambient pressure showed three endotherms at 413 K, 533 K and 973 K with weight losses of approximately 11%, 11% and 43% caused by partial dehydration, full dehydration and sulfate decomposition respectively. Interestingly, no clear evidence of dehydration was observed up to ~453 K and ~10.4 GPa, suggesting that pressure acts to stabilize the crystalline structure of blödite. The data collected allow to write the following equation of state, V(P, T) = V

  10. Facts and Suggestions from a Brief History of the Galilean Moons and Space Weathering

    Science.gov (United States)

    Cooper, John

    2010-05-01

    From Galileo Galilei's Starry Messenger of four centuries ago we began the long journey of Galilean moon exploration now planned to continue with the joint ESA-NASA Europa Jupiter System Mission. Nearly eighty years after this historic beginning, the Keplerian orbital motions of these moons could be understood in terms of universal laws of motion and gravitation with Newton's Mathematical Principles of Natural Philosophy of 1687. But now looking back from the present to long before the discovery of magnetospheric radio emissions from Jupiter by Burke and Franklin in 1955 [1], we can infer the first apparent evidence for magnetospheric space weathering of the moon surfaces only from the 1926 first report of Stebbins [2] on photometric measurements of surface albedo light curves. These observations established the tidal locking of rotational and orbital motions from leading-trailing albedo asymmetries that we now significantly (if not entirely) associate with space weathering effects of the moon-magnetosphere-moon interactions. Of all the remote and in-situ observations that followed, those of the Pioneer (1973-1974), Voyager (1979), and Galileo (1995-2003) missions, and of the supporting measurements that followed in passing by the Ulysses (1992), Cassini (2000), and New Horizons (2007) missions, the discovery of greatest impact for space weathering may have been the first detection of Io volcanism by the Voyagers [3]. Accelerated as pickup ions in the corotating planetary magnetic field of Jupiter, atoms and molecules from the volcanic plume ejecta provide the primary source of magnetospheric ions for interactions with the other Galilean moons. These interactions include simple surface implantation of the iogenic ions, erosion of surface materials by ion sputtering, and modification of surface chemistry induced by volume ionization from more penetrating ions and electrons. From the highest energy magnetospheric protons and heavier ions, these interactions can be

  11. Comparative study of icy patches on comet nuclei

    Science.gov (United States)

    Oklay, Nilda; Pommerol, Antoine; Barucci, Maria Antonietta; Sunshine, Jessica; Sierks, Holger; Pajola, Maurizio

    2016-07-01

    Cometary missions Deep Impact, EPOXI and Rosetta investigated the nuclei of comets 9P/Tempel 1, 103P/Hartley 2 and 67P/Churyumov-Gerasimenko respectively. Bright patches were observed on the surfaces of each of these three comets [1-5]. Of these, the surface of 67P is mapped at the highest spatial resolution via narrow angle camera (NAC) of the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS, [6]) on board the Rosetta spacecraft. OSIRIS NAC is equipped with twelve filters covering the wavelength range of 250 nm to 1000 nm. Various filters combinations are used during surface mapping. With high spatial resolution data of comet 67P, three types of bright features were detected on the comet surface: Clustered, isolated and bright boulders [2]. In the visible spectral range, clustered bright features on comet 67P display bluer spectral slopes than the average surface [2, 4] while isolated bright features on comet 67P have flat spectra [4]. Icy patches observed on the surface of comets 9P and 103P display bluer spectral slopes than the average surface [1, 5]. Clustered and isolated bright features are blue in the RGB composites generated by using the images taken in NIR, visible and NUV wavelengths [2, 4]. This is valid for the icy patches observed on comets 9P and 103P [1, 5]. Spectroscopic observations of bright patches on comets 9P and 103P confirmed the existence of water [1, 5]. There were more than a hundred of bright features detected on the northern hemisphere of comet 67P [2]. Analysis of those features from both multispectral data and spectroscopic data is an ongoing work. Water ice is detected in eight of the bright features so far [7]. Additionally, spectroscopic observations of two clustered bright features on the surface of comet 67P revealed the existence of water ice [3]. The spectral properties of one of the icy patches were studied by [4] using OSIRIS NAC images and compared with the spectral properties of the active regions observed

  12. The alteration of icy samples during sample acquisition

    Science.gov (United States)

    Mungas, G.; Bearman, G.; Beegle, L. W.; Hecht, M.; Peters, G. H.; Glucoft, J.; Strothers, K.

    2006-12-01

    Valid in situ scientific studies require both that samples be analyzed in as pristine condition as possible and that any modification from the pristine to the sampled state be well understood. While samples with low to high ice concentration are critical for the study of astrobiology and geology, they pose problems with respect to the sample acquisition, preparation and distribution systems (SPAD) upon which the analytical instruments depend. Most significant of the processes that occur during SPAD is sublimation or melting caused by thermal loading from drilling, coring, etc. as well as exposure to a dry low pressure ambient environment. These processes can alter the sample, as well as generating, meta-stable liquid water that can refreeze in the sample transfer mechanisms, interfering with proper operation and creating cross-contamination. We have investigated and quantified loss of volatiles such as H2O, CO, CO2, and organics contained within icy and powdered samples when acquired, processed and transferred. During development of the MSL rock crusher, for example, ice was observed to pressure-fuse and stick to the side even at -70C. We have investigated sublimation from sample acquisition at Martian temperature and pressure for a samples ranging from 10 to 100 water/dirt ratios. Using the RASP that will be on Phoenix, we have measured sublimation of ice during excavation at Martian pressure and find that the sublimation losses can range from 10 to 50 percent water. It is the thermal conductivity of the soil that determines local heat transport, and how much of the sample acquisition energy is wicked away into the soil and how much goes into the sample. Modeling of sample acquisition methods requires measurement of these parameters. There is a two phase model for thermal conductivity as a function of dirt/ice ratio but it needed to be validated. We used an ASTM method for measuring thermal conductivity and implemented it in the laboratory. The major conclusion is

  13. Jupiter Icy Moons Orbiter (JIMO) Electrical Systems Testbed

    Science.gov (United States)

    Trapp, Scott J.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission will send a spacecraft to explore three of Jupiter s moons (Callisto, Ganymede, and Europa), all of which show evidence of containing vast subterranean oceans beneath their icy surfaces. The evidence of these oceans was discovered by Galileo, and the moons are believed to have the three essential ingredients for life: water, energy, and the necessary chemical elements. Galileo has shown that melted water on Europa has been in contact with the surface of the moon in geologically recent times, and may still lie relatively close to the surface. This project will also introduce a revolutionary new form of electric propulsion powered by a nuclear fission reactor. This electric propulsion is called ion propulsion. It was used on a previous mission called Deep Space 1, proving that ion propulsion works for interplanetary travel. Since JIMO will be traveling farther from the sun, solar power will be difficult to supply the electric energy demanded by the mission. Therefore a nuclear reactor and a thermo-electric converter system will be necessary. Besides making the trip to three of Jupiter's moons - one after the other - a realistic possibility, this new form of power and propulsion opens up the rest of the outer solar system for future exploration. JIMO will fulfill its goals by exploring Europa first, with subsequent trips to the moons Callisto and Ganymede in order to provide comparisons key to understanding the evolution of all three. In order to ensure the stability and proper preparation of the electrical system on JIMO, the High Power AC Power Management and Distribution (PMAD) Test Bed is being developed. The testing on.this AC PMAD will consist of electrical performance verification of candidate power system components. Examples of these components are: high power AC switchgear, high power ACDC converters, AC power distribution units, DC power distribution units, etc. Throughout the course of the summer the over

  14. Secondary craters from large impacts on Europa and Ganymede: Ejecta size-velocity distributions on icy worlds, and the scaling of ejected blocks

    Science.gov (United States)

    Singer, Kelsi N.; McKinnon, William B.; Nowicki, L. T.

    2013-09-01

    We have mapped fields of secondary craters around three large primary craters on Europa and Ganymede and estimated the size and velocity of the fragments that formed the secondaries using updated scaling equations for ice impacts. We characterize the upper envelope of the fragment size-velocity distribution to obtain a function for the largest fragments at a given ejection velocity. Power-law velocity exponents found in our study of icy satellite secondary fields are compared to the exponents found for similar studies of mercurian, lunar, and martian craters; for all but basin-scale impacts, fragment size decreases more slowly with increasing ejection velocity than on rocky bodies. Spallation theory provides estimates of the size of ejected spall plates at a given velocity, but this theory predicts fragments considerably smaller than are necessary to form most of our observed secondaries. In general, ejecta fragment sizes scale with primary crater diameter and decrease with increasing ejection velocity, υej, by 1/υej or greater, and point-source scaling implies a relation between the two. The largest crater represented in any of these studies, Gilgamesh on Ganymede, exhibits a relatively steep velocity dependence. Extrapolating the results to the escape speed for each icy moon yields the size of the largest fragment that could later re-impact to form a so-called sesquinary crater, either on the parent moon or a neighboring satellite. We find that craters above 2 km in diameter on Europa and Ganymede are unlikely to be sesquinaries.

  15. Synthesis of novel ICIE16/BSG and ICIE16/BSG-NITRI bioglasses and description of ionic release kinetics upon immersion in SBF fluid: Effect of nitridation

    Science.gov (United States)

    Orgaz, Felipe; Amat, Daniel; Szycht, Olga; Dzika, Aleksandra; Barba, Flora; Becerra, José; Santos-Ruiz, Leonor

    2015-01-01

    A novel bioactive glass scaffold ICIE16/BSG has been prepared from a mixture of two different melt-derived glasses: a silicate bioglass (ICIE16) and a borosilicate bioglass (BSG). Combined processing techniques (gel casting and foam replication) were used to form three-dimensional, interconnected porous monolith scaffolds (Orgaz et al., 2016) [1]. They were then nitrided with a hot ammonia flow as described in (Aleixandre et al., 1973) [3] and (Nieto, 1984) [4] to synthesize the ICIE16/BSG-NITRI bioglass (Orgaz et al., 2016) [1]. Herein we present a flow chart summarizing the forming process, plus images of the resulting scaffold after sintering and drying. Bioactivity was characterized in vitro by immersion in simulated body fluid (SBF) for up to seven days. Data of ionic release kinetics upon SBF immersion are presented. PMID:26858981

  16. Synthesis of novel ICIE16/BSG and ICIE16/BSG-NITRI bioglasses and description of ionic release kinetics upon immersion in SBF fluid: Effect of nitridation

    Directory of Open Access Journals (Sweden)

    Felipe Orgaz

    2016-03-01

    Full Text Available A novel bioactive glass scaffold ICIE16/BSG has been prepared from a mixture of two different melt-derived glasses: a silicate bioglass (ICIE16 and a borosilicate bioglass (BSG. Combined processing techniques (gel casting and foam replication were used to form three-dimensional, interconnected porous monolith scaffolds (Orgaz et al., 2016 [1]. They were then nitrided with a hot ammonia flow as described in (Aleixandre et al., 1973 [3] and (Nieto, 1984 [4] to synthesize the ICIE16/BSG-NITRI bioglass (Orgaz et al., 2016 [1]. Herein we present a flow chart summarizing the forming process, plus images of the resulting scaffold after sintering and drying. Bioactivity was characterized in vitro by immersion in simulated body fluid (SBF for up to seven days. Data of ionic release kinetics upon SBF immersion are presented.

  17. A Possible Icy Kuiper Belt around HD 181327

    CERN Document Server

    Chen, Christine H; Smith, Paul S

    2008-01-01

    We have obtained a Gemini South T-ReCS Qa-band (18.3 micron) image and a Spitzer MIPS SED-mode observation of HD181327, an F5/F6V member of the ~12 Myr old beta Pictoris moving group. We resolve the disk in thermal-emission for the first time and find that the northern arm of the disk is 1.4x brighter than the southern arm. In addition, we detect a broad peak in the combined Spitzer IRS and MIPS spectra at 60 - 75 micron that may be produced by emission from crystalline water ice. We model the IRS and MIPS data using a size distribution of amorphous olivine and water ice grains (dn/da proportional to a^{-2.25} with a_{min} consistent with the minimum blow out size and a_{max} = 20 micron) located at a distance of 86.3 AU from the central star, as observed in previously published scattered-light images. Since the photo-desorption lifetime for the icy particles is ~1400 yr, significantly less than the estimated ~12 Myr age of the system, we hypothesize that we have detected debris that may be steadily replenish...

  18. Two-phase convection in the high-pressure ice layer of the large icy moons: geodynamical implications

    Science.gov (United States)

    Kalousova, K.; Sotin, C.; Tobie, G.; Choblet, G.; Grasset, O.

    2015-12-01

    The H2O layers of large icy satellites such as Ganymede, Callisto, or Titan probably include a liquid water ocean sandwiched between the deep high-pressure ice layer and the outer ice I shell [1]. It has been recently suggested that the high-pressure ice layer could be decoupled from the silicate core by a salty liquid water layer [2]. However, it is not clear whether accumulation of liquids at the bottom of the high-pressure layer is possible due to positive buoyancy of water with respect to high-pressure ice. Numerical simulation of this two-phase (i.e. ice and water) problem is challenging, which explains why very few studies have self-consistently handled the presence and transport of liquids within the solid ice [e.g. 3]. While using a simplified description of water production and transport, it was recently showed in [4] that (i) a significant fraction of the high-pressure layer reaches the melting point and (ii) the melt generation and its extraction to the overlying ocean significantly influence the global thermal evolution and interior structure of the large icy moons.Here, we treat the high-pressure ice layer as a compressible mixture of solid ice and liquid water [5]. Several aspects are investigated: (i) the effect of the water formation on the vigor of solid-state convection and its influence on the amount of heat that is transferred from the silicate mantle to the ocean; (ii) the fate of liquids within the upper thermal boundary layer - whether they freeze or reach the ocean; and (iii) the effect of salts and volatile compounds (potentially released from the rocky core) on the melting/freezing processes. Investigation of these aspects will allow us to address the thermo-chemical evolution of the internal ocean which is crucial to evaluate the astrobiological potential of large icy moons. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Hussmann et al. (2007), Treatise of

  19. Sublimation of Ices Containing Organics and/or Minerals and Implications for Icy Bodies Surface Structure and Spectral Properties

    Science.gov (United States)

    Poch, O.; Pommerol, A.; Jost, B.; Yoldi, Z.; Carrasco, N.; Szopa, C.; Thomas, N.

    2015-12-01

    The surfaces of many objects in the Solar System comprise substantial quantities of water ice either in pure form or mixed with minerals and/or organic molecules. Sublimation is a process responsible for shaping and changing the reflectance properties of these objects. We present laboratory data on the evolution of the structure and the visible and near-infrared spectral reflectance of icy surfaces made of mixtures of water ice and non-volatile components (complex organic matter and silicates), as they undergo sublimation of the water ice under low temperature and pressure conditions (Poch et al., under review). We prepared icy surfaces which are potential analogues of ices found on comets, icy satellites or trans-neptunian objects (TNOs). The experiments were carried out in the SCITEAS simulation setup recently built as part of the Laboratory for Outflow Studies of Sublimating Materials (LOSSy) at the University of Bern (Pommerol et al., 2015a). As the water ice sublimated, we observed in situ the formation of a sublimation lag deposit, or sublimation mantle, made of the non-volatiles at the top of the samples. The texture (porosity, internal cohesiveness etc.), the activity (outbursts and ejection of mantle fragments) and the spectro-photometric properties of this mantle are found to differ strongly depending on the chemical nature of the non-volatiles, the size of their particles, the way they are mixed with the volatile component and the dust/ice mass ratio. The results also indicate how the band depths of the sub-surface water ice evolve during the build-up of the sublimation mantle. These data provide useful references for interpreting remote-sensing observations of Rosetta (see Pommerol et al., 2015b), and also New Horizons. Poch, O., et al., under review in IcarusPommerol, A., et al., 2015a, Planet. Space Sci. 109-110, 106-122. http://dx.doi.org/10.1016/j.pss.2015.02.004Pommerol, A., et al., 2015b, Astronomy and Astrophysics, in press. http://dx.doi.org/10.1051/0004-6361/201525977

  20. Precoded OFDM System for ICI Mitigation over Time-Frequency Selective Fading Channels

    Institute of Scientific and Technical Information of China (English)

    LONG Yi; KUANG Linling; LU Jianhua

    2009-01-01

    In orthogonal frequency-division multiplexing (OFDM) systems, the capability to support high mo-bility is greatly limited by the intercarrier interference (ICI) caused by time-frequency selective fading chan-nels. This paper presents a precoded OFDM system for ICI mitigation. A precoder is introduced to relieve the ICI by transmitting N-point composite information symbols at twice the subcarrier interval. A Ha-damard-matrix-like pilot pattern is used to recover the composite information symbols in a postprocessor at the receiver. Simulations show that, compared to the conventional self-cancellation scheme, this scheme gives much better signal-to-interference-noise ratio performance with much less overhead. Furthermore, the scheme can support twice the vehicle speed in time-frequency selective fading channels than the standard OFDM systems without ICI mitigation.

  1. Zooplankton Biomass Data from Prince William Sound, Icy Bay and Yakutat Bay, Alaska 2010-2011

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset includes zooplankton biomass from Prince William Sound, Icy Bay and Yakutat Bay, Alaska. Zooplankton were sampled with a ring net (0.6 m diameter with...

  2. Common eiders nesting and arctic fox predation at Icy Cape, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report discusses the common eiders nesting and arctic fox predation at Icy Cape, Alaska. Study areas, methods, and results are discussed.

  3. Observing Outer Planet Satellites (except Titan) with JWST: Science Justification and Observational Requirements

    CERN Document Server

    Keszthelyi, Laszlo; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

    2015-01-01

    The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

  4. Observing outer planet satellites (except Titan) with JWST: Science justification and observational requirements

    Science.gov (United States)

    Kestay, Laszlo P.; Grundy, Will; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

    2016-01-01

    The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

  5. ICIS and Aurora B coregulate the microtubule depolymerase Kif2a.

    Science.gov (United States)

    Knowlton, Anne L; Vorozhko, Valeriya V; Lan, Weijie; Gorbsky, Gary J; Stukenberg, P Todd

    2009-05-12

    Kinesins in the mitotic spindle play major roles in determining spindle shape, size, and bipolarity, although specific regulation of these kinesins at distinct locations on the spindle is poorly understood. So that the forces that are required for spindle bipolarity are balanced, microtubule-depolymerizing kinesins are tightly regulated. Aurora B kinase phosphorylates the neck regions of the kinesin-13 family microtubule depolymerases Kif2a and mitotic centromere-associated kinesin (MCAK) and inhibits their depolymerase activities. How they are reactivated and how this is controlled independently on different kinetochore fibers is unknown. We show that inner centromere Kin-I stimulator (ICIS), which stimulates the related depolymerase MCAK, can reactivate Kif2a after Aurora B inhibition. When antibodies that block the ability of ICIS to activate Kif2a are injected into cells, monopolar spindles are generated. This phenotype is rescued by coinjection of anti-Nuf2 antibodies. We have performed a structure-function analysis of the ICIS protein and find that the N terminus of ICIS binds Aurora B and its regulators INCENP and TD60, whereas a central region binds MCAK, Kif2a, and microtubules, suggesting a scaffold function for ICIS. These data argue that ICIS and the chromosomal passenger complex (CPC) regulate Kif2a depolymerase activity.

  6. A Novel OFDM Channel Estimation Algorithm with ICI Mitigation over Fast Fading Channels

    Directory of Open Access Journals (Sweden)

    C. Tao

    2010-06-01

    Full Text Available Orthogonal frequency-division multiplexing (OFDM is well-known as a high-bit-rate transmission technique, but the Doppler frequency offset due to the high speed movement destroys the orthogonality of the subcarriers resulting in the intercarrier interference (ICI, and degrades the performance of the system at the same time. In this paper a novel OFDM channel estimation algorithm with ICI mitigation based on the ICI self-cancellation scheme is proposed. With this method, a more accurate channel estimation is obtained by comb-type double pilots and then ICI coefficients can be obtained to mitigate the ICI on each subcarrier under the assumption that the channel impulse response (CIR varies in a linear fashion. The theoretical analysis and simulation results show that the bit error rate (BER and spectral efficiency performances are improved significantly under high-speed mobility conditions (350 km/h – 500 km/h in comparison to ZHAO’s ICI self-cancellation scheme.

  7. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA.

  8. High energy electron processing of icy regoliths on Saturn's moons

    Science.gov (United States)

    Schaible, Micah; Johnson, Robert E.

    2015-11-01

    A unique space weathering phenomenon has been identified on several icy Saturnian moons. Cassini revealed anomalous lens shaped regions in both optical and thermal wavelengths, colloquially known as the 'PacMan' feature, which are centered on the leading hemispheres and approximately symmetric about the equators. In particular, the Cassini InfraRed Spectrometer (CIRS) measurements of thermal emission in the mid-IR showed that surface temperature variations during a diurnal cycle were smaller inside the anomalous regions. The locations of the anomalies were shown to closely match the expected deposition profile of high energy (~ MeV) electrons moving counter rotational to the moons, suggesting an energetic source to drive their formation. However, the mechanisms by which thermal conductivity enhancement occur lack quantitative comparison with theoretical and experimental results.Electron interactions with the grains can excite molecules, which, if near enough to an intergrain contact, can cause atoms or molecules to migrate into the contact region, thus increasing the contact volume or 'sintering' the grains. Sintering improves the thermal contact between grains, leading to increased effective thermal conductivity of the regolith. Equations previously developed to describe material behavior in nuclear reactor were used to estimate the timescale for the energetic electrons to increase the contact volume sufficiently to describe the enhanced thermal conductivity of the anomalous regions. In order to properly constrain the sintering calculations, the unique electron energy distribution measured in the vicinity of each of the moons was used in the calculations, and molecular dynamics simulations of excited electrons in water ice were carried out to determine the length scale for an average electron excitation or ionization event. This length scale determines the distance from the primary reaction at which electrons can still be mobilized to move into the contact region

  9. Chemistry and Spectroscopy of Frozen Chloride Salts on Icy Bodies

    Science.gov (United States)

    Johnson, Paul; Thomas, Elena C.; Hodyss, Robert; Vu, Tuan; Choukroun, Mathieu

    2016-10-01

    Currently, our understanding of the chemical composition of Europa's surface is our best means of inferring constraints on the subsurface ocean composition and its subsequent habitability. The bulk of our knowledge of Europa surface chemistry can be traced to near infrared spectra recorded by the Near Infrared Mapping Spectrometer on the Galileo spacecraft. However, the usefulness of this and other remote sensing data is limited by the availability of spectral libraries of candidate materials under relevant conditions (temperature, thermal/radiation history, etc.). Chloride salts are expected to exist on the surface of Europa, and other icy bodies, based on geochemical predictions of the ocean composition. In order to help improve our understanding of Europa's surface composition, we have conducted a study of frozen chloride-salt brines prepared under simulated Europa surface conditions (vacuum, temperature, and UV irradiation) using both near IR and Raman spectroscopies. Specifically, Raman spectroscopy was used to determine the hydration states of various chloride salts as a function of temperature. Near IR spectroscopy of identically prepared samples was used to provide reference reflectance spectra of the identified hydrated salts. Our results indicate that at temperatures ranging from 80 K to 233 K, hydrohalite is formed from the freezing of NaCl brines, while the freezing of KCl solutions does not form KCl hydrates. In addition, the freezing of MgCl2 solutions forms a stable hexahydrate, and the freezing of CaCl2 solutions forms a hexahydrate, a tetrahydrate, and a dihydrate. Dehydration of the salts was observed as temperatures were increased, leading to a succession of hydration states in the case of CaCl2.

  10. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  11. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  12. The effects of laterally varying icy shell structure on the tidal response of Europa and Ganymede

    Science.gov (United States)

    Wahr, J. M.; A, G.; Zhong, S.

    2013-12-01

    One of the long-sought objectives of an icy moon orbiter or fly-by mission, has been to use tidal observations to help determine the existence of a liquid ocean and characteristics of the overlying icy shell. The radio science component of such a mission could be used to estimate the tidal potential Love number k2 for gravity. And if there is an on-board laser altimeter, it could be used to determine the radial displacement Love number h2. Knowledge of either of those Love numbers could provide information on the presence of an ocean beneath the icy outer shell, and the two Love numbers could be combined to place constraints on the thickness of the icy shell. Though if a subsurface ocean exists, complications could conceivably arise if the icy outer shell has significant lateral variations in elastic thickness or shear modulus, or if the ocean is not global in extent so that the icy shell is grounded in places but floating in others. In these cases, the tidal deformation pattern would not be represented as the sum of degree 2 harmonics, and so the results could not be characterized in terms of a single Love number. In this study, by solving a set of tidal loading problems with laterally variable icy shell structures (for which the existence of an ocean layer is assumed), we investigate how those structures might complicate the interpretation of the tide measurements, and we discuss how to extract information regarding the interior structure of Ganymede and Europa from measurements of their tidal response.

  13. The Origins and Evolution of Molecules in Icy Solids

    Science.gov (United States)

    Hudson, Reggie L.; Moore, Marla H.

    2010-01-01

    Astronomical observations of the past few decades have revealed the existence of a variety of molecules in extraterrestrial ices. These molecules include H2O, CO, and CO2, and organics such as CH4, CH30H, and C2H6. Some ices are dominated by polar molecules, while non-polar species appear to dominate others. Observations, mainly in the radio and IR regions, have allowed the inference of other solid-phase molecules whose formation remains difficult to explain by gas-phase chemistry alone. Several laboratory research groups have reported on extensive experiments on the solid-phase reaction chemistry of icy materials, generally as initiated by either ionizing radiation or vacuum-UV photons. These experiments not only permit molecular identifications to be made from astronomical observations, but also allow predictions of yet unidentified molecules. This laboratory approach has evolved over more than 30 years with much of the earliest work focusing on complex mixtures thought to represent either cometary or interstellar ices. Although those early experiments documented a rich solid-state photo- and radiation chemistry, they revealed few details of reactions for particular molecules, partly due to the multi-component nature of the samples. Since then, model systems have been examined that allow the chemistry of individual species and specific reactions to be probed. Reactions involving most of the smaller astronomical molecules have now been studied and specific processes identified. Current laboratory work suggests that a variety of reactions occur in extraterrestrial ices, including acid-base processes, radical dimerizations, proton transfers, oxidations, reductions, and isomerizations. This workshop presentation will focus on chemical reactions relevant to solar system and interstellar ices. While most of the work will be drawn from that to which the speaker has contributed, results from other laboratories also will be included. Suggestions for future studies will be

  14. A novel sputtering technique: Inductively Coupled Impulse Sputtering (ICIS)

    Science.gov (United States)

    Loch, D. A. L.; Ehiasarian, A. P.

    2012-09-01

    Sputtering magnetic materials with magnetron based systems has the disadvantage of field quenching and variation of alloy composition with target erosion. The advantage of eliminating magnetic fields in the chamber is that this enables sputtered particles to move along the electric field more uniformly. Inductively coupled impulse sputtering (ICIS) is a form of high power impulse magnetron sputtering (HIPIMS) without a magnetic field where a high density plasma is produced by a high power radio frequency (RF) coil in order to sputter the target and ionise the metal vapour. In this emerging technology, the effects of power and pressure on the ionisation and deposition process are not known. The setup comprises of a 13.56 MHz pulsed RF coil pulsed with a duty cycle of 25 %. A pulsed DC voltage of 1900 V was applied to the cathode to attract Argon ions and initiate sputtering. Optical emission spectra (OES) for Cu and Ti neutrals and ions at constant pressure show a linear intensity increase for peak RF powers of 500 W - 3400 W and a steep drop of intensity for a power of 4500 W. Argon neutrals show a linear increase for powers of 500 W - 2300 W and a saturation of intensity between 2300 W - 4500 W. The influence of pressure on the process was studied at a constant peak RF power of 2300 W. With increasing pressure the ionisation degree increased. The microstructure of the coatings shows globular growth at 2.95×10-2 mbar and large-grain columnar growth at 1.2×10-1 mbar. Bottom coverage of unbiased vias with a width of 0.360 μm and aspect ratio of 2.5:1 increased from 15 % to 20 % for this pressure range. The current work has shown that the concept of combining a RF powered coil with a magnet-free high voltage pulsed DC powered cathode is feasible and produces very stable plasma. The experiments have shown a significant influence of power and pressure on the plasma and coating microstructure.

  15. Elimination of numerical Cherenkov instability in flowing-plasma particle-in-cell simulations by using Galilean coordinates

    Science.gov (United States)

    Lehe, Remi; Kirchen, Manuel; Godfrey, Brendan B.; Maier, Andreas R.; Vay, Jean-Luc

    2016-11-01

    Particle-in-cell (PIC) simulations of relativistic flowing plasmas are of key interest to several fields of physics (including, e.g., laser-wakefield acceleration, when viewed in a Lorentz-boosted frame) but remain sometimes infeasible due to the well-known numerical Cherenkov instability (NCI). In this article, we show that, for a plasma drifting at a uniform relativistic velocity, the NCI can be eliminated by simply integrating the PIC equations in Galilean coordinates that follow the plasma (also sometimes known as comoving coordinates) within a spectral analytical framework. The elimination of the NCI is verified empirically and confirmed by a theoretical analysis of the instability. Moreover, it is shown that this method is applicable both to Cartesian geometry and to cylindrical geometry with azimuthal Fourier decomposition.

  16. Elimination of Numerical Cherenkov Instability in flowing-plasma Particle-In-Cell simulations by using Galilean coordinates

    CERN Document Server

    Lehe, Remi; Godfrey, Brendan B; Maier, Andreas R; Vay, Jean-Luc

    2016-01-01

    Particle-In-Cell (PIC) simulations of relativistic flowing plasmas are of key interest to several fields of physics (including e.g. laser-wakefield acceleration, when viewed in a Lorentz-boosted frame), but remain sometimes infeasible due to the well-known numerical Cherenkov instability (NCI). In this article, we show that, for a plasma drifting at a uniform relativistic velocity, the NCI can be eliminated by simply integrating the PIC equations in Galilean coordinates that follow the plasma (also sometimes known as comoving coordinates) within a spectral analytical framework. The elimination of the NCI is verified empirically and confirmed by a theoretical analysis of the instability. Moreover, it is shown that this method is applicable both to Cartesian geometry and to cylindrical geometry with azimuthal Fourier decomposition.

  17. Stabilizing effect of large average initial velocity in forced dissipative PDEs invariant with respect to Galilean transformations

    Science.gov (United States)

    Cyranka, Jacek; Zgliczyński, Piotr

    2016-10-01

    We describe a topological method to study the dynamics of dissipative PDEs on a torus with rapidly oscillating forcing terms. We show that a dissipative PDE, which is invariant with respect to the Galilean transformations, with a large average initial velocity can be reduced to a problem with rapidly oscillating forcing terms. We apply the technique to the viscous Burgers' equation, and the incompressible 2D Navier-Stokes equations with a time-dependent forcing. We prove that for a large initial average speed the equation admits a bounded eternal solution, which attracts all other solutions forward in time. For the incompressible 3D Navier-Stokes equations we establish the existence of a locally attracting solution.

  18. Abrupt climate transition of icy worlds from snowball to moist or runaway greenhouse

    Science.gov (United States)

    Yang, Jun; Ding, Feng; Ramirez, Ramses M.; Peltier, W. R.; Hu, Yongyun; Liu, Yonggang

    2017-08-01

    Ongoing and future space missions aim to identify potentially habitable planets in our Solar System and beyond. Planetary habitability is determined not only by a planet's current stellar insolation and atmospheric properties, but also by the evolutionary history of its climate. It has been suggested that icy planets and moons become habitable after their initial ice shield melts as their host stars brighten. Here we show from global climate model simulations that a habitable state is not achieved in the climatic evolution of those icy planets and moons that possess an inactive carbonate-silicate cycle and low concentrations of greenhouse gases. Examples for such planetary bodies are the icy moons Europa and Enceladus, and certain icy exoplanets orbiting G and F stars. We find that the stellar fluxes that are required to overcome a planet's initial snowball state are so large that they lead to significant water loss and preclude a habitable planet. Specifically, they exceed the moist greenhouse limit, at which water vapour accumulates at high altitudes where it can readily escape, or the runaway greenhouse limit, at which the strength of the greenhouse increases until the oceans boil away. We suggest that some icy planetary bodies may transition directly to a moist or runaway greenhouse without passing through a habitable Earth-like state.

  19. Kidnapping small icy asteroids in Earth near encounter to harbour life and to deflect trajectory

    Science.gov (United States)

    Fargion, Daniele

    2016-07-01

    The inter-planetary flight for human being is under danger because of unscreened and lethal solar flare radioactive showers. The screening of the astronauts by huge superconducting magnetic fields is unrealistic by many reasons. On the contrary the ability to reach nearby icy asteroids, to harbour there a complete undergound room where ecological life systems are first set, this goal may offer a later natural and safe currier for future human stations and enterprise. The need to deflect such a small size (a few thousands tons objects) maybe achieved by micro nuclear engines able to dig the asteroid icy skin, to heat and propel the soil by a synchronous jet engine array, bending and driving it to any desired trajectories. The need for such a wide collection of icy asteroid stations, often in a robotic ibernated state, it will offer the safe help station, raft in the wide space sea, where to collect material or energy in long human planetary travels.

  20. Subsiding OOB Emission and ICI Power Using iPOWER Pulse in OFDM Systems

    Directory of Open Access Journals (Sweden)

    KAMAL, S.

    2016-02-01

    Full Text Available A novel family of Nyquist-I pulses called iPOWER is proposed with a new design parameter that provides an extra degree of freedom for a certain roll-off factor. The proposed pulse is examined and compared with other existing pulses in terms of out-of-band (OOB power, intercarrier interference (ICI power, signal-to-interference ratio (SIR power, and bit-error-rate (BER in orthogonal frequency division multiplexing (OFDM systems. The BER was analyzed in the presence of carrier frequency offset (CFO, which introduces ICI in OFDM-based systems. Eye diagram tool is also used to visually analyze the performance of the proposed pulse. Simulation results show that the iPOWER pulse performs better in terms of OOB power, ICI power, SIR power, and improving BER in comparison to other existing pulses in OFDM-based systems.

  1. A Passive Probe for Subsurface Oceans and Liquid Water in Jupiter's Icy Moons

    CERN Document Server

    Romero-Wolf, Andrew; Maiwald, Frank; Heggy, Essam; Ries, Paul; Liewer, Kurt

    2014-01-01

    We describe an interferometric reflectometer method for passive detection of subsurface oceans and liquid water in Jovian icy moons using Jupiter's decametric radio emission (DAM). The DAM flux density exceeds 3,000 times the galactic background in the neighborhood of the Jovian icy moons, providing a signal that could be used for passive radio sounding. An instrument located between the icy moon and Jupiter could sample the DAM emission along with its echoes reflected in the ice layer of the target moon. Cross-correlating the direct emission with the echoes would provide a measurement of the ice shell thickness along with its dielectric properties. The interferometric reflectometer provides a simple solution to sub-Jovian radio sounding of ice shells that is complementary to ice penetrating radar measurements better suited to measurements in the anti-Jovian hemisphere that shadows Jupiter's strong decametric emission. The passive nature of this technique also serves as risk reduction in case of radar transmi...

  2. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  3. The estrogen antagonist ICI 182,780 reduces cancellous bone volume in female rats.

    Science.gov (United States)

    Gallagher, A; Chambers, T J; Tobias, J H

    1993-12-01

    Although estrogen is thought to protect the skeleton by inhibiting bone resorption, we have also found that in the rat, estrogen stimulates cancellous bone formation. However, the extent to which the various skeletal actions of estrogen are mediated by classical estrogen receptors remains unclear. Although estrogen receptor antagonists such as tamoxifen have been used to study this question, interpretation of the results is complicated by the fact that this agent also acts as a partial estrogen agonist. However, the recent development of estrogen antagonists devoid of agonist activity provides an opportunity to explore this question further. We, therefore, investigated the effect of administration of the pure estrogen antagonist ICI 182,780 on the skeleton of adult female rats. We found that ICI 182,780 reduced bone volume at the proximal tibial metaphysis by approximately 30%, associated with an increase in osteoclast surface. We then investigated the effect of ICI 182,780 on the anabolic action of estrogen. We used ovariectomized rats treated with 3-amino-1-hydroxypropylidene-1-bisphosphonate to inhibit bone resorption, thereby preventing any increase in bone formation as a result of the stimulation of bone resorption due to estrogen deficiency. 17 beta-Estradiol (1 micrograms/kg) stimulated cancellous bone formation in such animals by approximately 8-fold; this increase was abolished when ICI 182,780 was also given. In contrast, ICI 182,780 affected neither longitudinal nor periosteal tibial growth in either intact animals or ovariectomized rats given estradiol or vehicle. We conclude that ICI 182,780 reduces cancellous bone volume in the rat by antagonizing estrogen's actions on bone formation and resorption, suggesting that these processes are both mediated by classical estrogen receptors.

  4. An Overview of the Jupiter Icy Moons Orbiter (JIMO) Mission, Environments, and Materials Challenges

    Science.gov (United States)

    Edwards, Dave

    2012-01-01

    Congress authorized NASA's Prometheus Project in February 2003, with the first Prometheus mission slated to explore the icy moons of Jupiter with the following main objectives: (1) Develop a nuclear reactor that would provide unprecedented levels of power and show that it could be processed safely and operated reliably in space for long-duration. (2) Explore the three icy moons of Jupiter -- Callisto, Ganymede, and Europa -- and return science data that would meet the scientific goals as set forth in the Decadal Survey Report of the National Academy of Sciences.

  5. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  6. Equivalent Validity of Identification-Commitment-Inventory (HSA-ICI (Validez del Cuestionario de Identificación y Compromiso (HSA-ICI

    Directory of Open Access Journals (Sweden)

    Joan Guàrdia

    2011-04-01

    Full Text Available The main purpose of this study was to demonstrate the validity of the Identification-Commitment-Inventory (HSA-ICI in two European samples (from Spain and Portugal. The ICI was proposed by Quijano and collaborators as part of the Human System Audit (HSA, a conceptual model and set of tools designed for evaluation and intervention in Human Resources Systems (HRS. The underlying factor structure of the instrument was tested with samples of Spanish (n = 625 and Portuguese (n = 520 employees - in combination and separately - working in the health care sector. Confirmatory factor analysis with a test of invariance across groups was conducted. The results show that the theoretical model fits the observed data of the general sample (χ2 = 2643.12, P = .046; RMSEA = .028; RMR = .041; GFI = .983; AGFI =. 977; CFI = .994, replicating the results of a previous study. When the samples were analysed separately, the measurement structure presented a better fit in the Spanish sample than in the Portuguese sample. The overall difference was not large - due to being influenced at the item level by some contextual aspects - but was just sufficient to obtain statistical significance (χ2Tucker-Lewis = 48.23; df = 1; P < .001. This work provides evidence supporting the use of the HSA-ICI. The implications of these results for future research are discussed.

  7. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  8. A Study of the Construct Validity of the Interactive Computer Interview System (ICIS) Using Student Evaluations as the Outcome Measure

    Science.gov (United States)

    Gardner, Robby Christopher

    2009-01-01

    The primary objective of this study was to compare the individual teacher interview scores from the Interactive Computer Interview System (ICIS) with their students' responses to "The Steps to Excellence Student Questionnaire". Specifically, the study examined the correlation among the teacher interviews across four themes of the ICIS ("Knowledge…

  9. A passive low frequency instrument for radio wave sounding the subsurface oceans of the Jovian icy moons: An instrument concept

    Science.gov (United States)

    Hartogh, P.; Ilyushin, Ya. A.

    2016-10-01

    Exploration of subsurface oceans on Jovian icy moons is a key issue of the icy moons' geology. Electromagnetic wave propagation is the only way to probe their icy mantles from the orbit. In the present paper, a principal concept of a passive interferometric instrument for deep sounding of the icy moons' crust is proposed. Its working principle is measuring and correlating Jupiter's radio wave emissions with reflections from the deep sub-surface of the icy moons. A number of the functional aspects of the proposed experiment are studied, in particular, impact of the wave scattering on the surface terrain on the instrument performance and digital sampling of the noisy signal. Results of the test of the laboratory prototype of the instrument are also presented in the paper.

  10. It's Far, It's Small, It's Cool: It's an Icy Exoplanet!

    Science.gov (United States)

    2006-01-01

    Using a network of telescopes scattered across the globe, including the Danish 1.54m telescope at ESO La Silla (Chile), astronomers [1] discovered a new extrasolar planet significantly more Earth-like than any other planet found so far. The planet, which is only about 5 times as massive as the Earth, circles its parent star in about 10 years. It is the least massive exoplanet around an ordinary star detected so far and also the coolest [2]. The planet most certainly has a rocky/icy surface. Its discovery marks a groundbreaking result in the search for planets that support life. ESO PR Photo 03a/06 ESO PR Photo 03a/06 Artist's Impression of the Newly Found Exoplanet The new planet, designated by the unglamorous identifier of OGLE-2005-BLG-390Lb, orbits a red star five times less massive than the Sun and located at a distance of about 20,000 light years, not far from the centre of our Milky Way galaxy. Its relatively cool parent star and large orbit implies that the likely surface temperature of the planet is 220 degrees Centigrade below zero, too cold for liquid water. It is likely to have a thin atmosphere, like the Earth, but its rocky surface is probably deeply buried beneath frozen oceans. It may therefore more closely resemble a more massive version of Pluto, rather than the rocky inner planets like Earth and Venus. "This planet is actually the first and only planet that has been discovered so far that is in agreement with the theories for how our Solar System formed ", said Uffe Gråe Jørgensen (Niels Bohr Institute, Copenhagen, Denmark), member of the team. The favoured theoretical explanation for the formation of planetary systems proposes that solid 'planetesimals' accumulate to build up planetary cores, which then accrete nebular gas - to form giant planets - if they are sufficiently massive. Around red dwarfs, the most common stars of our Galaxy, this model favours the formation of Earth- to Neptune-mass planets being between 1 and 10 times the Earth

  11. 76 FR 21330 - Lynn Canal/Icy Straits Resource Advisory Committee

    Science.gov (United States)

    2011-04-15

    ...The Lynn Canal/Icy Straits Resource Advisory Committee will meet in Juneau, Alaska, April 25, 2011. The purpose of this meeting is to orient the new appointees as to the Secure Rural Schools and Community Self-Determination Act of 2008, provide operational guidelines, discuss and adopt specific bylaws for the RAC, and elect a RAC...

  12. Le CERN va devoir supprimer quelques 600 postes d'ici a 2007

    CERN Multimedia

    2002-01-01

    "Le Laboratoire europeen pour la physique des particules (CERN) qui procede actuellement a la construction du LHC (Large Hadron Collider) , le plus grand accelerateur de particules du monde, va devoir supprimer, comme cela avait ete evoque en juin, quelques 600 postes d'ici a 2007" (1 paragraph).

  13. Concurrent Validity of the "Working with Others Scale" of the ICIS Employment Interview System

    Science.gov (United States)

    Cassidy, Martha W.

    2011-01-01

    The purpose of this study was to determine if the Working with Others Scale from the American Association of School Personnel Administrators (AASPA) Interactive Computer Interview System (ICIS) was a valid predictor of practicing teachers' interpersonal skills and abilities to work well with colleagues. Participants in the study were all employed…

  14. An Examination of Teaching a Networking Strategy to Job Seekers. ICI Tools for Inclusion.

    Science.gov (United States)

    Gandolfo, Cecilia; Graham, Audrey

    This issue brief describes the outcomes of a study conducted by the Institute for Community Inclusion (ICI) that investigated the effectiveness of a training workshop on using a networking approach to job development for people with disabilities. The two-day workshop focused on teaching how to identify and use connections such as family members,…

  15. Le CERN va supprimer 600 postes d'ici a 2007

    CERN Multimedia

    2002-01-01

    "Le Laboratoire europeen pour la physique des particules (CERN), qui doit economiser quelque 340 millions d'euros jusqu'en 2008, va reduire ses effectifs de 600 postes d'ici a 2007, a annonce jeudi son porte-parole, James Gillies" (1/2/ page).

  16. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  17. The compression behavior of blödite at low and high temperature up to ∼10 GPa: Implications for the stability of hydrous sulfates on icy planetary bodies

    Science.gov (United States)

    Comodi, Paola; Stagno, Vincenzo; Zucchini, Azzurra; Fei, Yingwei; Prakapenka, Vitali

    2017-03-01

    Recent satellite inferences of hydrous sulfates as recurrent minerals on the surface of icy planetary bodies link with the potential mineral composition of their interior. Blödite, a mixed Mg-Na sulfate, is here taken as representative mineral of icy satellites surface to investigate its crystal structure and stability at conditions of the interior of icy bodies. To this aim we performed in situ synchrotron angle-dispersive X-ray powder diffraction experiments on natural blödite at pressures up to ∼10.4 GPa and temperatures from ∼118.8 K to ∼490.0 K using diamond anvil cell technique to investigate the compression behavior and establish a low-to-high temperature equation of state that can be used as reference when modeling the interior of sulfate-rich icy satellites such as Ganymede. The experimentally determined volume expansivity, α, varies from 7.6 (7) 10-5 K-1 at 0.0001 GPa (from 118.8 to 413.15 K) to 2.6 (3) 10-5 K-1 at 10 GPa (from 313.0 to 453.0 K) with a δα/δP coefficient = -5.6(9)10-6 GPa-1 K-1. The bulk modulus calculated from the least squares fitting of P-V data on the isotherm at 413 K using a second-order Birch - Murnaghan equation of state is 38(5) GPa, which gives the value of δK/δT equal to 0.01(5) GPa K-1. The thermo-baric behavior of blödite appears strongly anisotropic with c lattice parameter being more deformed with respect to a and b. Thermogravimetric analyses performed at ambient pressure showed three endotherms at 413 K, 533 K and 973 K with weight losses of approximately 11%, 11% and 43% caused by partial dehydration, full dehydration and sulfate decomposition respectively. Interestingly, no clear evidence of dehydration was observed up to ∼453 K and ∼10.4 GPa, suggesting that pressure acts to stabilize the crystalline structure of blödite. The data collected allow to write the following equation of state, V(P, T) = V0[1 + 7.6(7)10- 5ΔT - 0.026(3)P - 5.6(9)10- 6PΔT-6.6(9)10- 6PΔT)] from which the density of bl

  18. Correspondence between the contracted BTZ solution of cosmological topological massive gravity and two-dimensional Galilean conformal algebra

    Energy Technology Data Exchange (ETDEWEB)

    Setare, M R; Kamali, V, E-mail: rezakord@ipm.ir, E-mail: vkamali1362@gmail.com [Department of Science, Payame Noor University, Bijar (Iran, Islamic Republic of)

    2011-11-07

    We show that a BTZ black hole solution of cosmological topological massive gravity has a hidden conformal symmetry. In this regard, we consider the wave equation of a massless scalar field propagating in BTZ spacetime and find that the wave equation could be written in terms of the SL(2, R) quadratic Casimir. From the conformal coordinates, the temperatures of the dual conformal field theories (CFTs) could be read directly. Moreover, we compute the microscopic entropy of the dual CFT by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole. Then, we consider Galilean conformal algebras (GCA), which arises as a contraction of relativistic conformal algebras (x {yields} {epsilon}x, t {yields} t, {epsilon} {yields} 0). We show that there is a correspondence between GCA{sub 2} on the boundary and contracted BTZ in the bulk. For this purpose we obtain the central charges and temperatures of GCA{sub 2}. Then, we compute the microscopic entropy of the GCA{sub 2} by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole in a non-relativistic limit. The absorption cross section of a near-region scalar field also matches the microscopic absorption cross section of the dual GCA{sub 2}. So we find further evidence that shows correspondence between a contracted BTZ black hole and two-dimensional GCA.

  19. Landform Erosion and Volatile Redistribution on Ganymede and Callisto

    Science.gov (United States)

    Moore, Jeffrey Morgan; Howard, Alan D.; McKinnon, William B.; Schenk, Paul M.; Wood, Stephen E.

    2009-01-01

    We have been modeling landscape evolution on the Galilean satellites driven by volatile transport. Our work directly addresses some of the most fundamental issues pertinent to deciphering icy Galilean satellite geologic histories by employing techniques currently at the forefront of terrestrial, martian, and icy satellite landscape evolution studies [e.g., 1-6], including modeling of surface and subsurface energy and volatile exchanges, and computer simulation of long-term landform evolution by a variety of processes. A quantitative understanding of the expression and rates of landform erosion, and of volatile redistribution on landforms, is especially essential in interpreting endogenic landforms that have, in many cases, been significantly modified by erosion [e.g., 7-9].

  20. Modeling the Jovian subnebula: II - Composition of regular satellites ices

    CERN Document Server

    Mousis, O; Mousis, Olivier; Alibert, Yann

    2005-01-01

    We use the evolutionary turbulent model of Jupiter's subnebula described by Alibert et al. (2005a) to constrain the composition of ices incorporated in its regular icy satellites. We consider CO2, CO, CH4, N2, NH3, H2S, Ar, Kr, and Xe as the major volatile species existing in the gas-phase of the solar nebula. All these volatile species, except CO2 which crystallized as a pure condensate, are assumed to be trapped by H2O to form hydrates or clathrate hydrates in the solar nebula. Once condensed, these ices were incorporated into the growing planetesimals produced in the feeding zone of proto-Jupiter. Some of these solids then flowed from the solar nebula to the subnebula, and may have been accreted by the forming Jovian regular satellites. We show that ices embedded in solids entering at early epochs into the Jovian subdisk were all vaporized. This leads us to consider two different scenarios of regular icy satellites formation in order to estimate the composition of the ices they contain. In the first scenar...

  1. Gravity Fields and Interiors of the Saturnian Satellites

    Science.gov (United States)

    Rappaport, N. J.; Armstrong, J. W.; Asmar, Sami W.; Iess, L.; Tortora, P.; Somenzi, L.; Zingoni, F.

    2006-01-01

    This viewgraph presentation reviews the Gravity Science Objectives and accomplishments of the Cassini Radio Science Team: (1) Mass and density of icy satellites (2) Quadrupole field of Titan and Rhea (3) Dynamic Love number of Titan (4) Moment of inertia of Titan (in collaboration with the Radar Team) (5) Gravity field of Saturn. The proposed measurements for the extended tour are: (1) Quadrupole field of Enceladus (2) More accurate measurement of Titan k2 (3) Local gravity/topography correlations for Iapetus (4) Verification/disproof of "Pioneer anomaly".

  2. Radar probing of Jovian icy moons: Understanding subsurface water and structure detectability in the JUICE and Europa missions

    Science.gov (United States)

    Heggy, Essam; Scabbia, Giovanni; Bruzzone, Lorenzo; Pappalardo, Robert T.

    2017-03-01

    Radar probing of Jovian icy satellites is fundamental for understanding the moons' origin and their thermal evolution as potential habitable environments in our Solar System. Using the current state of knowledge of the geological and geophysical properties of Ganymede, Europa and Callisto, we perform a comprehensive radar detectability study to quantify the exploration depth and the lower limit for subsurface identification of water and key tectonic structural elements. To achieve these objectives, we establish parametric dielectric models that reflect different hypotheses on the formation and thermal evolution of each moon. The models are then used for FDTD radar propagation simulations at the 9-MHz sounding frequency proposed for both ESA JUICE and NASA Europa missions. We investigate the detectability above the galactic noise level of four predominant subsurface features: brittle-ductile interfaces, shallow faults, brine aquifers, and the hypothesized global oceans. For Ganymede, our results suggest that the brittle-ductile interface could be within radar detectability range in the bright terrains, but is more challenging for the dark terrains. Moreover, understanding the slope variation of the brittle-ductile interface is possible after clutter reduction and focusing. For Europa, the detection of shallow subsurface structural elements few kilometers deep (such as fractures, faults and brine lenses) is achievable and not compromised by surface clutter. The objective of detecting the potential deep global ocean on Europa is also doable under both the convective and conductive hypotheses. Finally, for Callisto, radar waves can achieve an average penetration depth of ∼15 km, although the current understanding of Callisto's subsurface dielectric properties does not suggest sufficiently strong contrasts to produce unambiguous radar returns.

  3. Porosity effects on crystallization kinetics of Amorphous Solid Water: Implications for cold icy objects in the Outer Solar System

    Science.gov (United States)

    Mitchell, Emily H.; Raut, Ujjwal; Baragiola, Raul A.

    2015-11-01

    Crystalline ice has been identified on the cold surfaces of most icy satellites and TNOs [1]. This is surprising since accretion of water vapor at temperatures (T isothermal transition from amorphous to fully crystalline phase was characterized by analyzing the time-dependent evolution of the OH-stretch absorption band using transmission infrared spectroscopy. Our initial results show that τc decreases with increasing porosity; for instance, a film deposited at 45° was observed to crystallize ~6 times faster than a film deposited at 0°. The preliminary estimate of the porosity of the 45° film is ~50% higher than that of the film deposited at normal incidence. Our findings can explain the reported variation in temperature-dependent τc [2] and contribute to the understanding of crystalline ice on cold bodies in the Outer Solar System.1. Mastrapa, R.M.E. et al. In: Gudipati, M.S. & Castillo-Rogez, J., Eds, The Science of Solar System Ices, Springer, New York, 2013.2. Baragiola, R.A. In: Devlin & Buch, Eds, Water in Confining Geometries, Springer-Verlag, 2003.3. Jewitt, D.C. & Luu, J., Nature 432, 731, 2004.4. Porter, S.B. et al. Icarus 208, 492, 2010.5. Stevenson, K.P., et al. Science 283, 1505, 1999.6. Francis, R.J. & O’Hare, D., J. Chem. Soc., Dalton Trans., 3133, 1998.7. Kirsch, B.L. et al., J. Phys. Chem. B., 108, 12698, 2004.

  4. Testing of Icy-Soil Sample Delivery in Simulated Martian Conditions (Animation)

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation This movie clip shows testing under simulated Mars conditions on Earth in preparation for NASA's Phoenix Mars Lander using its robotic arm for delivering a sample to the doors of a laboratory oven. The icy soil used in the testing flowed easily from the scoop during all tests at Martian temperatures. On Mars, icy soil has stuck to the scoop, a surprise that may be related to composition of the soil at the landing site. This testing was done at Honeybee Robotics Spacecraft Mechanisms Corp., New York, which supplied the Phoenix scoop. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASAaE(TM)s Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. Post main sequence evolution of icy minor planets: Implications for water retention and white dwarf pollution

    CERN Document Server

    Malamud, Uri

    2016-01-01

    Most observations of polluted white dwarf atmospheres are consistent with accretion of water depleted planetary material. Among tens of known cases, merely two cases involve accretion of objects that contain a considerable mass fraction of water. The purpose of this study is to investigate the relative scarcity of these detections. Based on a new and highly detailed model, we evaluate the retention of water inside icy minor planets during the high luminosity stellar evolution that follows the main sequence. Our model fully considers the thermal, physical, and chemical evolution of icy bodies, following their internal differentiation as well as water depletion, from the moment of their birth and through all stellar evolution phases preceding the formation of the white dwarf. We also account for different initial compositions and formation times. Our results show that previous studies have either underestimated or overestimated water retention. We also reaffirm that water can survive in a variety of circumstanc...

  6. Complexity-reduced ICI cancellation for OFDM system over doubly-selective channels

    Institute of Scientific and Technical Information of China (English)

    Xi Xiaoping; Zhang Can

    2009-01-01

    In doubly-selective fading wireless channel, the conventional orthogonal frequency division multiplexing (OFDM) receivers for inter-carrier interference (ICI) compensation require extensive computations. To obtain an effective balance between performance and complexity, the whole channel response matrix was decomposed into a sequence of submatrix, and then a novel equalizer based on minimum mean square error (MMSE) criterion was presented to combat the ICI. Furthermore, a simple ordering-based decision-feedback equalizer (DFE) was derived to exploit the temperal diversity gain offered by mobile channels. Numerical studies illustrate that although the MMSE equalizer still suffers from error floor, whereas the DFE equalizer exhibits significant performance improvement. The advantage of the proposed scheme indicates its potential applications in the future broadband wireless systems.

  7. A Low Frequency Radio and Radar Instrument to Explore Jupiter's Icy Moons

    Science.gov (United States)

    Kurth, W. S.; Gurnett, D. A.; Plaut, J.; Bolton, S. J.; Farrell, W. M.; Desch, M. D.; Kaiser, M. L.; Zarka, P.; Lecacheux, A.; Bale, S. D.

    2003-01-01

    The addition of a comprehensive wave investigation to the Jupiter Icy Moons Orbiter (JIMO) science payload will provide a broad range of information on the icy moons of Jupiter including the detection of subsurface liquid oceans; mapping of their ionospheres; their interaction with the magnetospheric environment; and on the Jovian magnetosphere. These measurements are obtained through the use of both passive and active (sounding) means over broad frequency ranges. The frequency range of interest extends from less than 1 Hz to 40 MHz for passive measurements, from approximately 1 kHz to a few MHz for magnetospheric and ionospheric sounding, and between 1 and approximately 10 MHz for subsurface radar sounding. An instrument to detect subsurface radar sounding, magnetospheric interactions, and ionospheric sounding is discussed.

  8. Saturn's Icy Moon Rhea: a Prediction for Bulk Chemical Composition and Physical Structure at the Time of the Cassini Spacecraft First Flyby

    CERN Document Server

    Prentice, A J R

    2005-01-01

    I report a model for the formation of Saturn's family of mid-sized icy moons to coincide with the first flypast of Rhea by the Cassini Orbiter spacecraft on 26 November 2005. It is proposed that these moons had condensed from a concentric family of orbiting gas rings that were cast off some 4600 Myr ago by the contracting proto-Saturnian cloud. Numerical and structural models for Rhea are constructed on the basis of a computed bulk chemical mix of hydrated rock (mass fraction 0.385), H2O ice (0.395), and NH3 ice (0.220). The large proportion of NH3 in the ice mass inhibits the formation of the dense crystalline phase II of H2O ice at the satellite's centre. This may explain the absence of compressional features on the surface. The favoured model of Rhea has a chemically uniform interior and is very cold. The satellite is nearly isodense and the predicted value of the axial moment-of-inertia factor is C/MR^2 = 0.399 +/- 0.004. NH3 is unstable at Saturn's distance from the Sun, except near the polar regions of ...

  9. 77 FR 55452 - Lynn Canal-Icy Strait Resource Advisory Committee

    Science.gov (United States)

    2012-09-10

    ...The Lynn Canal-Icy Strait Resource Advisory Committee (LC-IS RAC) will meet in Juneau, AK. The committee is authorized under the Secure Rural Schools and Community Self-Determination Act (Pub. L. 112- 141) (the Act) and operates in compliance with the Federal Advisory Committee Act. The purpose of the committee is to improve collaborative relationships and to provide advice and recommendations......

  10. Experimental study of surface erosion processes of the icy moons of Jupiter

    CERN Document Server

    Galli, A; Wurz, P; Jost, B; Scheer, J A; Vorburger, A; Tulej, M; Thomas, N; Wieser, M; Barabash, S

    2015-01-01

    We use an existing laboratory facility for space hardware calibration in vacuum to study the impact of energetic ions on water ice. The experiment is intended to simulate the conditions on the surface of Jupiter's icy moons. We present first results of ion sputtering in a sample of porous ice, including the first experimental results for sulphur ion sputtering of ice. The results confirm theoretical predictions and extrapolations from previous sputtering experiments obtained at different impact angles for non-porous water ice.

  11. Draft Genome Sequence of Corynebacterium amycolatum Strain ICIS 53 Isolated from a Female Urogenital Tract.

    Science.gov (United States)

    Gladysheva, Irina V; Cherkasov, Sergey V; Khlopko, Yuriy A; Plotnikov, Andrey O; Gogoleva, Natalya E

    2016-11-10

    This report describes the draft genome sequence of Corynebacterium amycolatum strain ICIS 53, isolated from the reproductive tract of a healthy woman. The size of the genome was 2,460,257 bp (58.98% G+C content). Annotation revealed 2,173 coding sequences, including 2,076 proteins, 7 rRNA genes, and 53 tRNA genes.

  12. Inward technology transfer as an interactive process: A case study of ICI.

    OpenAIRE

    Trott, Paul

    1993-01-01

    This thesis sets out to explore the area of inward technology transfer and in particular the notion of "receptivity". A conceptual framework is developed which identifies four major components of the inward technology transfer process. These are: "Awareness"- "Association"-"Assimilation"-"Application". Using this conceptual device a series of investigations are undertaken into three of these components. These studies are conducted within a number of businesses within ICI Che...

  13. Electron irradiation effects in icy regoliths: The PacMan anomalies at Saturn

    Science.gov (United States)

    Schaible, Micah; Johnson, Robert E.; Zhigilei, Leo

    2016-10-01

    The anomalous regions identified on the leading hemispheres of the icy Saturnian moons, colloquially known as the 'PacMan' features, were found to have larger thermal inertia than the surrounding regions. The locations of the anomalies were shown to closely match the expected deposition profile of high energy (~ MeV) electrons moving counter rotational to the moons, suggesting an energetic source to drive their formation. Here we consider the mechanisms by which electron radiation can produce changes in the thermal conductivity of an icy regolith and compare estimates obtained from theoretical and experimental results with the measured thermal inertia and grain impact resurfacing rates on the icy moons.Electron interactions with the grains can both create and anneal defects in the crystalline lattice, and deposited energy drives molecular diffusion. Mobilized molecules accumulate in the contact region between grains due to the surface energy minimum, thus increasing the contact volume or 'sintering' the grains. Previously developed sintering rate equations and measured electron energy distributions near the icy moons were used to estimate the timescale for the energetic electrons to increase the contact volume sufficiently to produce the enhanced thermal conductivity of the anomalous regions. In order to properly constrain the sintering calculations, molecular dynamics (MD) simulations of electron interactions in water ice were carried out to determine the number and diffusion length of excited molecules. Water molecules were artificially excited both in a water ice bulk and near a grain surface, and several ice polymorphs relevant to ice grain formation in outer solar system conditions were considered. Comparing the estimated sintering timescales to micrometeorite resurfacing rates indicates that grains must be small (~5um) and/or irregularly shaped with a high defect density in the contact regions. Since there is some disagreement in these grains sizes and

  14. Power-Conversion Concept Designed for the Jupiter Icy Moons Orbiter

    Science.gov (United States)

    Mason, Lee S.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission being developed by NASA's Office of Space Science under Project Prometheus. JIMO is examining the potential of nuclear electric propulsion (NEP) technology to efficiently deliver scientific payloads to three of Jupiter's moons: Callisto, Ganymede, and Europa. A critical element of the NEP spacecraft is the space reactor power system (SRPS), consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD).

  15. Water production rate of Comet C/2009 P1 (Garradd) throughout the 2011-2012 apparition: Evidence for an icy grain halo

    Science.gov (United States)

    Combi, M. R.; Mäkinen, J. T. T.; Bertaux, J.-L.; Quémerais, E.; Ferron, S.; Fougere, N.

    2013-07-01

    The all-sky hydrogen Lyman-alpha camera, SWAN (Solar Wind Anisotropies), on the SOlar and Heliospheric Observatory (SOHO) satellite made observations of the hydrogen coma of Comet C/2009 P1 (Garradd) throughout its apparition from August 15, 2011 through April 6, 2012. SOHO has been operating in a halo orbit around the Earth-Sun L1 Lagrange point since its launch in late 1995. Most water vapor produced by the comet is ultimately photodissociated into two H atoms and one O atom producing a huge atomic hydrogen coma that is routinely observed in the daily full-sky SWAN images in comets of sufficient brightness. Water production rates were calculated from 117 images over 8 months of the apparition yielding about 1 observation every 2 days on the average. The activity during much of the pre-perihelion leg was much larger than the post-perihelion leg and varied rather irregularly, not following the more typical steadily increasing trend with decreasing heliocentric distance. It varied generally between 1 and 3 × 1029 s-1, with a peak value of 4 × 1029 s-1 on November 3, 2011, 50 days before perihelion. The elevated production rate from the very large SWAN field-of-view compared with smaller aperture observations could be consistent with water production from icy particles rather than from gas sublimated directly from the nucleus. Scenarios for the nature and production of the icy grain source are explored. During the post-perihelion leg the water production rate decreased more uniformly and typically from 2 × 1029 s-1 at perihelion, approximately as r-3.2, where r is the heliocentric distance. This is consistent with water sublimation from a reasonably constant total surface area.

  16. Identification of ICIS-1, a new protein involved in cilia stability.

    Science.gov (United States)

    Ponsard, Cecile; Skowron-Zwarg, Marie; Seltzer, Virginie; Perret, Eric; Gallinger, Julia; Fisch, Cathy; Dupuis-Williams, Pascale; Caruso, Nathalie; Middendorp, Sandrine; Tournier, Frederic

    2007-01-01

    Cilia are specialized organelles that exert critical functions in numerous organisms, including that of cell motility, fluid transport and protozoan locomotion. Ciliary architecture and function strictly depend on basal body formation, migration and axoneme elongation. Numerous ultrastructural studies have been undertaken in different species to elucidate the process of ciliogenesis. Recent analyses have led to identification of genes specifically expressed in ciliated organisms, but most proteins involved in ciliogenesis remain uncharacterized. Using human nasal epithelial cells capable of ciliary differentiation in vitro, differential display was carried out to identify new proteins associated with ciliogenesis. We isolated a new gene, ICIS-1 (Involved in CIlia Stability-1), upregulated during mucociliary differentiation. This gene is localized within the TGF-beta1 promoter and is ubiquitously expressed in human tissues. Functional analyses of gene expression inhibition by RNA interference in Paramecium tetraurelia indicated that the ICIS-1 homologue interfered with cilia stability or formation. These findings demonstrate that ICIS-1 is a new protein associated with ciliated cells and potentially related to cilia stability.

  17. Preliminary Design of ICI-based Multimedia for Reconceptualizing Electric Conceptions at Universitas Pendidikan Indonesia

    Science.gov (United States)

    Samsudin, A.; Suhandi, A.; Rusdiana, D.; Kaniawati, I.

    2016-08-01

    Interactive Conceptual Instruction (ICI) based Multimedia has been developed to represent the electric concepts turn into more real and meaningful learning. The initial design of ICI based multimedia is a multimedia computer that allows users to explore the entire electric concepts in terms of the existing conceptual and practical. Pre-service physics teachers should be provided with the learning that could optimize the conceptions held by re-conceptualizing concepts in Basic Physics II, especially the concepts about electricity. To collect and to analyze the data genuinely and comprehensively, researchers utilized a developing method of ADDIE which has comprehensive steps: analyzing, design, development, implementation, and evaluation. The ADDIE developing steps has been utilized to describe comprehensively from the phase of analysis program up until the evaluation program. Based on data analysis, it can be concluded that ICI-based multimedia could effectively increase the pre-service physics teachers’ understanding on electric conceptions for re-conceptualizing electric conceptions at Universitas Pendidikan Indonesia.

  18. NOTE: Preliminary Measurements of the Cryogenic Dielectric Properties of Water-Ammonia Ices: Implications for Radar Observations of Icy Satellites

    Science.gov (United States)

    Lorenz, Ralph D.

    1998-12-01

    I report preliminary measurements of the complex permittivity of frozen aqueous ammonia solutions at liquid nitrogen temperatures, representative of those in the saturnian system. The real part of the dielectric constant of 30% ammonia ice is around 4.5 at near-DC frequencies and at ∼1 MHz, compared with around 3.1 for pure water ice. The loss tangents of ammonia-rich ices seem somewhat (∼50%) higher than those for water ice, for which the few low-temperature experiments to date indicate values comparable with predictions by Thompson and Squyres (1990,Icarus86, 336-354) and Maetzler (1998, inSolar System Ices(B. Schmitt, C. DeBergh, and M. Festou, Eds.), pp. 241-257, Kluwer Academic, Dordrecht), but considerably higher than models by Chybaet al. (1998,Icarus, in press). Ammonia-rich ice may reconcile the radar and optical appearance of Titan's surface: the detectability of water-ammonia ice on Titan by the Cassini mission and the implications for Titan's origin and evolution are discussed.

  19. About Galilean transformation on a mass variable system and two bodies gravitational system with variable mass and damping-anti damping effect due to star wind

    CERN Document Server

    Lopez, G V

    2012-01-01

    We make an observation about Galilean transformation on a 1-D mass variable systems which leads us to the right way to deal with these systems. Then using this observation, we study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-anti damping effect due to star wind during its motion. for this system, a constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion, and the period of the body is studied using the constant of motion of the system. An application to the comet motion is given, using the comet Halley as an example.

  20. Fractal analysis on Enceladus: a global ocean underneath the icy crust

    Science.gov (United States)

    Lucchetti, Alice; Pozzobon, Riccardo; Mazzarini, Francesco; Cremonese, Gabriele; Simioni, Emanuele; Massironi, Matteo

    2016-04-01

    Plumes of water have been observed erupting from Enceladus' south polar terrain providing direct evidence of a reservoir of liquid below the surface, that could be considered global or just a small body of water concentrated at its south pole. Gravity data collected during the spacecraft's several close flyby over the south polar region determined that the icy shell above the liquid ocean must be 30-40 km thick extending from the south pole up to 50°S (Iess et al. 2014). The hypothesis of a global ocean beneath the icy crust has been raised even in a recent paper of Thomas et al. (2015) thanks to the measurements of the very slight wobble that Enceladus displays as it orbits Saturn. In this work we support the hypothesis of the presence of an ocean layer using the fractal percolation theory. This method allowed us to estimate the icy shell thickness values in different regions of Enceladus from the south polar terrain up to the north pole. The spatial distribution of fractures on Enceladus has been analyzed in terms of their self-similar clustering and a two-point correlation method was used to measure the fractal dimension of the fractures population (Mazzarini, 2004, 2010). A self-similar clustering of fractures is characterized by a correlation coefficient with a size range defined by a lower and upper cut-off, that represent a mechanical discontinuity and the thickness of the fractured icy crust, thus connected to the liquid reservoir. We mapped the fractures on Enceladus surface based on April 2010 global mosaic from Cassini mission and applied the fractal method firstly to the south polar terrain finding indeed a fractal correlation of fractures and providing an ice shell thickness of ~40 km. Then, we analyzed fractures of four different regions around the equator and around the north pole inferring an overall ice shell thickness ranging from 35 to 45 km. Our results are in agreement with the gravity observations (Iess et al., 2014) and the mechanical models

  1. Eclipses of the inner satellites of Jupiter observed in 2015

    CERN Document Server

    Saquet, E; Colas, F; Arlot, J -E; Robert, V; Christophe, B; Dechambre, O

    2016-01-01

    During the 2014-2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies. We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction. We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These obs...

  2. Saturn's satellites - Near-infrared spectrophotometry (0.65-2.5 microns) of the leading and trailing sides and compositional implications

    Science.gov (United States)

    Steele, A.; Clark, R. N.; Brown, R. H.; Owensby, P. D.

    1984-01-01

    Water ice absorptions at 2.0, 1.5, and 1.25 microns are noted in near-IR spectra of Tethys, Dione, Rhea, Iapetus, and Hyperion, and the weak 1.04-micron ice absorption, which is detected for Rhea and Dione, is studied to establish band depth upper limits. The leading-trailing side 1.04-micron ice band depth differences on Saturn's satellites are similar to those for the Galilean satellites, indicating possible surface modification by magnetospheric charged particle bombardment. Limits are obtained for the amounts of particulates, trapped gases, and ammonium hydroxide on the surface. With the exception of the dark side of Iapetus, the surfaces of all of Saturn's satellites are nearly pure ice water.

  3. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  4. Martian CO2 icy surface mysterious evolution with insolation during spring and summer season

    Science.gov (United States)

    Pilorget, C.; Douté, S.; Vincendon, M.

    2016-12-01

    On Mars, the evolution of the CO2 reservoirs is one of the key aspects to decipher the climate changes. During winter, up to 30% of the atmosphere (composed of 95% of CO2) condenses at the surface to form seasonal polar caps, which completely sublime in spring, except in the South where a residual cap persists during summer. During spring and summer, the CO2 ice caps exhibit a mysterious evolution of their apparent albedo that looks correlated with the insolation. These radiative properties are, however, challenging to retrieve precisely on Mars, mostly because of the presence of aerosols in the atmosphere. Here we use both HiRISE/MRO high resolution images and CRISM/MRO VIS-NIR multi-angular hyperspectral data from the South residual cap (6 regions), corrected from the aerosol contribution, to investigate this mysterious behavior and determine the energy budget of the icy surface through the retrieval of the directional-hemispheric albedo. In particular, CRISM multi-angular dataset enables to determine the BRDF of the surface, decoupled from the aerosol contribution, which also brings new constrains on the ice structure. Both HiRISE and CRISM data show a continuous increase of the nadir reflectance factor of the icy surface until Ls270, followed by a decrease during the summer season, at both local and regional scale. Different classes of surface spectro-photometric behaviors are observed, the variations being likely linked to the composition, grain micro-texture and surface roughness of polar materials. In particular, the directional-hemispheric albedo calculated at 750 nm is typically 10-15% higher than the reflectance factor measured at nadir and exhibits similar seasonal behavior. In the meantime ice cracking is observed in HiRISE images after Ls270, thus without being correlated with the albedo increase. We will discuss these results and their implications for the characterization of the CO2 icy surfaces of Mars and their seasonal evolution.

  5. Technology for a Thermo-chemical Ice Penetrator for Icy Moons

    Science.gov (United States)

    Arenberg, Jonathan; Harpole, George; Zamel, James; Sen, Bashwar; Lee, Greg; Ross, Floyd; Retherford, Kurt D.

    2016-10-01

    The ability to place sensors or to take samples below the ice surface enables a wide variety of potential scientific investigations. Penetrating an ice cap can be accomplished via a mechanical drill, laser drill, kinetic impactor, or heated penetrator. This poster reports on the development of technology for the latter most option, namely a self-heated probe driven by an exothermic chemical reaction: a Thermo-chemical ice penetrator (TChIP). Our penetrator design employs a eutectic mix of alkali metals that produce an exothermic reaction upon contact with an icy surface. This reaction increases once the ice starts melting, so no external power is required. This technology is inspired by a classified Cold-War era program developed at Northrop Grumman for the US Navy. Terrestrial demonstration of this technology took place in the Arctic; however, this device cannot be considered high TRL for application at the icy moons of the solar system due to the environmental differences between Earth's Arctic and the icy moons. These differences demand a TChIP design specific to these cold, low mass, airless worlds. It is expected that this model of TChIP performance will be complex, incorporating all of the forces on the penetrator, gravity, the thermo-chemistry at the interface between penetrator and ice, and multi-phase heat and mass transport, and hydrodynamics. Our initial efforts are aimed at the development of a validated set of tools and simulations to predict the performance of the penetrator for both the environment found on these icy moons and for a terrestrial environment. The purpose of the inclusion of the terrestrial environment is to aid in model validation. Once developed and validated, our models will allow us to design penetrators for a specific scientific application on a specific body. This poster discusses the range of scientific investigations that are enabled by TChIP. We also introduce the development plan to advance TChIP to the point where it can be

  6. Mid-infrared spectroscopy to better characterize icy moon surface compositions

    Science.gov (United States)

    Young, Cindy L.; Wray, James J.; Hand, Kevin P.; Poston, Michael; Carlson, Robert W.; Clark, Roger Nelson; Spencer, John R.; Jennings, Donald

    2016-10-01

    Previous spectroscopy work on icy moons has focused primarily on the visible and near-IR portion of the spectrum due to challenges presented by a low signal to noise ratio at the longer wavelengths. However, the mid-IR is the region of the strongest fundamental vibrations of many important types of molecules (e.g., organics) and has the potential to reveal unique compositional information [1]. We use the wealth of data that is now available from Cassini's Composite Infrared Spectrometer (CIRS) to average spectra over similar regions to improve the signal to noise, helping to reveal spectral features never before observed.Our initial work has already led to the detection and tentative laboratory identification of the first spectral features observed for any icy moon in the mid-IR [2]. On Iapetus' dark terrain, we found an emissivity feature at ~855 cm-1 and a possible doublet at 660 and 690 cm-1 that does not correspond to any known instrument artifacts. We attributed the 855 cm-1 feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths [e.g., 3, 4]. Silicates on the dark terrains of Saturn's icy moons have been suspected for decades, but there have been no definitive detections until this work.We measured the vacuum, low temperature mid-IR spectra of various fine-grained powdered silicates, including Mg-rich serpentines, often present in meteorites. Some of these materials do have emissivity features near 855 cm-1 and exhibit a doublet. Presently, we are continuing to comb the CIRS icy moon database for spectral features (particularly focusing on the warmer surfaces in the Saturn system) and are performing further vacuum chamber measurements to experiment with more sample types and ice/sample mixtures to determine the impacts of changing conditions in the chamber on features. We are also working to understand how surface porosity and mixing with various darkening agents may

  7. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  8. Yeasts for Global Happiness: report of the 14th International Congress on Yeasts (ICY14) held in Awaji Island.

    Science.gov (United States)

    Watanabe, Daisuke; Takagi, Hiroshi

    2017-02-01

    The 14th International Congress on Yeasts (ICY14) was held at Awaji Yumebutai International Conference Center (Awaji, Hyogo) in Japan from 11 to 15 September 2016. The main slogan of ICY14 was 'Yeasts for Global Happiness', which enabled us to acknowledge the high-potential usefulness of yeasts contributing to the global happiness in terms of food/beverage, health/medicine and energy/environment industries, as well as to basic biosciences. In addition, two more concepts were introduced: 'from Japan to the world' and 'from senior to junior'. As it was the first ICY meeting held in Japan or other Asian countries, ICY14 provided a good opportunity to widely spread the great achievements by Japanese and Asian yeast researchers, such as those by the 2016 Nobel Laureate Dr. Yoshinori Ohsumi, and also, to convey the fun and importance of yeasts to the next generation of researchers from Asia and all over the world. As a result, a total of 426 yeast lovers from 42 countries (225 overseas and 201 domestic participants) with different generations attended ICY14 to share the latest knowledge of a wide range of yeast research fields and to join active and constructive scientific discussions. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  9. An investigation into the cardiac and pulmonary beta-adrenoceptor blocking activity of ICI 66,082 in man.

    Science.gov (United States)

    Marlin, G E; Kumana, C R; Kaye, C M; Smith, D M; Turner, P

    1975-04-01

    1 Oral ICI 66,082 (200 mg) or water (control treatment) were each administered to six healthy volunteers. 2 The heart rate (HR) and peak flow rate (PFR) were measured at rest and during vigorous exercise before and at intervals up to 24 h after each treatment. 3 ICI 66,082 produced significant reductions in exercise HR at all times compared with the changes after the control treatment (P less than 0.001), whereas with resting HR, corresponding significant reductions only occurred at 2,3 and 4 h (P less than 0.05). 4 Although there was no change in resting PFR, significant reductions in exercise PFR, compared with the changes after the control treatment, occurred at all times excepting at 2 h after ICI 66,082 (P less than 0.025). 5 The findings are consistent with ICI 66,082 possessing partial cardioselectivity. 6 Plasma levels and renal excretion of the drug were determined. Urinary recovery was variable which, together with the plasma concentration/effect relationships obtained, raise the possibility that ICI 66,082 is metabolized in man.

  10. An investigation into the cardiac and pulmonary beta-adrenoceptor blocking activity of ICI 66,082 in man.

    Science.gov (United States)

    Marlin, G E; Kumana, C R; Kaye, C M; Smith, D M; Turner, P

    1975-01-01

    1 Oral ICI 66,082 (200 mg) or water (control treatment) were each administered to six healthy volunteers. 2 The heart rate (HR) and peak flow rate (PFR) were measured at rest and during vigorous exercise before and at intervals up to 24 h after each treatment. 3 ICI 66,082 produced significant reductions in exercise HR at all times compared with the changes after the control treatment (P less than 0.001), whereas with resting HR, corresponding significant reductions only occurred at 2,3 and 4 h (P less than 0.05). 4 Although there was no change in resting PFR, significant reductions in exercise PFR, compared with the changes after the control treatment, occurred at all times excepting at 2 h after ICI 66,082 (P less than 0.025). 5 The findings are consistent with ICI 66,082 possessing partial cardioselectivity. 6 Plasma levels and renal excretion of the drug were determined. Urinary recovery was variable which, together with the plasma concentration/effect relationships obtained, raise the possibility that ICI 66,082 is metabolized in man. PMID:1234497

  11. Gap-Opening, Disk Clearing, and the Survival of the Regular Satellites of Jupiter and Saturn

    Science.gov (United States)

    Estrada, P. R.; Mosqueira, I.

    2003-01-01

    It is only recently that the theory of disk-companion interactions yields migration rates due to the gas tidal torque that are in agreement with numerical simulations and up to an order of magnitude slower than previous estimates. Also, for a weakly turbulent disk, the gap size is controlled primarily by the damping length of acoustic waves launched by the secondary at Lindblad resonances, which in turn depends on whether the waves are 2D or 3D. At least for small azimuthal wavenumbers this damping length is of the order of the radial location of the Lindblad resonance. This may have important consequences for disk dispersal in satellite systems. In the case of Jupiter, it means that the inner Galilean satellites may have jointly opened a gap. On the other hand, in Saturn's system the satellites inside of Titan are probably too small to have opened gaps in the gas disk at the time of their formation; but the possibility exists that, by effectively clearing the gas disk inside its own orbit, Titan may have allowed smaller satellites to survive, depending on whether Titan can clear the disk in a timescale comparable to the migration rates due to gas drag and gas tidal torque for these objects.

  12. Dynamics of Artificial Satellites around Europa

    Directory of Open Access Journals (Sweden)

    Jean Paulo dos Santos Carvalho

    2013-01-01

    Full Text Available A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA and Jupiter Icy Moon Explorer (JUICE, ESA. In this paper, we search for orbits around Europa with long lifetimes. Here, we develop the disturbing potential in closed form up to the second order to analyze the effects caused on the orbital elements of an artificial satellite around Europa. The equations of motion are developed in closed form to avoid expansions in power series of the eccentricity and inclination. We found polar orbits with long lifetimes. This type of orbits reduces considerably the maintenance cost of the orbit. We show a formula to calculate the critical inclination of orbits around Europa taking into account the disturbing potential due to the nonspherical shape of the central body and the perturbation of the third body.

  13. Experimentally Testing Hydrothermal Vent Origin of Life on Enceladus and Other Icy/Ocean Worlds.

    Science.gov (United States)

    Barge, Laura M; White, Lauren M

    2017-09-01

    We review various laboratory strategies and methods that can be utilized to simulate prebiotic processes and origin of life in hydrothermal vent systems on icy/ocean worlds. Crucial steps that could be simulated in the laboratory include simulations of water-rock chemistry (e.g., serpentinization) to produce hydrothermal fluids, the types of mineral catalysts and energy gradients produced in vent interfaces where hydrothermal fluids interface with the surrounding seawater, and simulations of biologically relevant chemistry in flow-through gradient systems (i.e., far-from-equilibrium experiments). We describe some examples of experimental designs in detail, which are adaptable and could be used to test particular hypotheses about ocean world energetics or mineral/organic chemistry. Enceladus among the ocean worlds provides an ideal test case, since the pressure at the ocean floor is more easily simulated in the lab. Results for Enceladus could be extrapolated with further experiments and modeling to understand other ocean worlds. Key Words: Enceladus-Ocean worlds-Icy worlds-Hydrothermal vent-Iron sulfide-Gradient. Astrobiology 17, 820-833.

  14. Icy outbursts from comet 67P/Churyumov-Gerasimenko as observed by the Alice FUV spectrograph

    Science.gov (United States)

    Steffl, Andrew Joseph; A'Hearn, Michael F.; Bertaux, Jean-Loup; Feaga, Lori M.; Feldman, Paul D.; Noonan, John; Parker, Joel Wm.; Schindhelm, Eric; Stern, S. Alan; Weaver, Harold A.

    2016-10-01

    Since the Rosetta spacecraft's historic rendezvous with 67P/Churyumov-Gerasimenko on 6 August 2014, the Alice far-ultraviolet spectrograph (700-2050Å) has monitored gas and dust emissions from the comet. During this time, Alice has observed several large dust outbursts. During such outbursts, the brightness of sunlight reflected from dust can increase by almost two orders of magnitude on timescales of a few tens of minutes. Typically, the reflectance spectrum of dust is very similar to that of the pre-perihelion nucleus: dark and relatively featureless with a blue spectral slope. However, a subset of the dust outbursts show a markedly different character with dust that is bright--in some cases brighter than the sunlit nucleus itself-- and displaying a strong absorption feature around 1700Å, characteristic of water ice. In such outbursts, the observed "dust" is likely to consist primarily of icy grains. We focus on two of these icy outbursts that occurred on 10 July 2015 and 13 September 2015 showing spectra from before, during, and after the events and comparing them to spectra of the nucleus obtained contemporaneously and from several months before and after perihelion.

  15. Impact jetting of water ice, with application to the accretion of icy planetesimals and Pluto

    Science.gov (United States)

    Mckinnon, William B.

    1989-01-01

    Jetting can occur during oblique impacts of water-ice bodies at relative velocities as low as 500 m/sec, because of the low Hugoniot elastic limit and high compressibility of ice compared to rock. In jetted ice, incipient melting, complete melting, and incipient vaporization occur, upon release to low pressure, at impact velocities of 1.3, 2.0, and 2.7 km/sec, respectively, much less than the 3.4, 4.4, and 5.3 km/sec, required in head-on collisions. Uncertainties in the shock equation-of-state may allow complete melting during jetting of relative velocities as low as 1.2 km/sec. Because jet speeds exceed impact speeds during the accretion of icy bodies greater than a few 100 km in radius, there may be a significant loss of icy material. Thus, jetting during a Charon-forming collision (and not vaporization) may account for Pluto-Charon's relatively large rock/ice ratio, should the C/O ratio of the solar nebula turn out to be too low to sufficiently raise the rock/ice ratio of outer solar nebula condensates by formation of noncondensable CO.

  16. Analytical model of impact disruption of satellites and asteroids

    Science.gov (United States)

    Leliwa-Kopystyński, J.; Włodarczyk, I.; Burchell, M. J.

    2016-04-01

    A model of impact disruption of the bodies with sizes from the laboratory scale to that of an order of 100 km is developed. On the lowermost end of the target size the model is based on the numerous laboratory data related to the mass-velocity distribution of the impact produced fragments. On the minor-planets scale the model is supported by the data related to the largest observed craters on small icy satellites and on some asteroids (Leliwa-Kopystynski, J., Burchell, M.J., Lowen, D. [2008]. Icarus 195, 817-826). The model takes into account the target disruption and the dispersion of the impact produced fragments against the intermolecular forces acting on the surfaces of the contacts of the fragments and against self-gravitation of the target. The head-on collisions of non-rotating and non-porous targets and impactors are considered. The impactor delivers kinetic energy but its mass is neglected in comparison to mass of the target. For this simple case the analytical formulae for specific disruption energy as well as for specific energy of formation of the largest craters are found. They depend on a set of parameters. Of these the most important (i.e. with the greatest influence on the final result) are three rather weakly known parameters. They are: (i) The exponent γ in the distribution function of the fragments. (ii) The characteristic velocity v0 that appears in the velocity distribution of the ejected fragments. (iii) The exponent β in the mass-velocity distribution. The influence of the choice of the numerical values of these parameters on the final results has been studied. Another group of parameters contains the relevant material data. They are: (a) The energy σ of breaking of the intermolecular bonds of the target material per unit of the fragment surface and (b) the density ρ of the target. According to our calculations the transition between the strength regime and the gravitational regime is in the range of the target radius from ∼0.4 km to

  17. Jesus the Galilean

    African Journals Online (AJOL)

    century philosophical movement stressing the importance of reason, .... think and believe and one should not too easily say that historical problems such as ..... village with a population of ten to twelve thousand (see Overman 1988:162). It was.

  18. Galilean relativistic fluid mechanics

    OpenAIRE

    Ván, Péter

    2015-01-01

    Single component nonrelativistic dissipative fluids are treated independently of reference frames and flow-frames. First the basic fields and their balances, then the related thermodynamic relations and the entropy production are calculated and the linear constitutive relations are given. The usual basic fields of mass, momentum, energy and their current densities, the heat flux, pressure tensor and diffusion flux are the time- and spacelike components of the third order mass-momentum-energy ...

  19. Satellite data compression

    CERN Document Server

    Huang, Bormin

    2011-01-01

    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  20. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  1. Systematic investigation of the low-energy dipole excitations in 176,178,180Hf within rotational, translational and Galilean invariant quasiparticle RPA

    Science.gov (United States)

    Guliyev, E.; Kuliev, A. A.; Ertugral, F.

    2013-10-01

    Low-energy magnetic and electric dipole excitations in the even-even isotopes 176-180Hf have been systematically studied within the rotational, translational and Galilean invariant Quasiparticle Random Phase Approximation (QRPA). The results of the calculations show that most of the states predicted to have magnetic character and the computed M1 strength in these nuclei is less strongly fragmented than in mid-shell isotopes. The results of the calculations are in good agreement with experimental data. The results of the calculations indicate the presence of a few prominent negative parity dipole K=1 states in the energy investigated region. The comparison of the calculations with the available experimental data makes possible the interpretation of the states where parity could not be assigned experimentally.

  2. The Status that the program to relieve set-point for the number of operable ICIs is applied to OPR1000

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Kyung-ho; Moon, Sang-rae [KHNP, Daejeon (Korea, Republic of)

    2016-10-15

    The Core Operating Limit Supervisory System (COLSS) of OPR1000 monitors in-core neutron power distribution, Linear Heat Rate (LHR) and Departure from Nucleate Boiling Ratio (DNBR) using In-Core Instrumentation (ICI). It is required that above 75% of ICI be operable to perform this functions. 45 EA strings of ICI have been installed and operated in Hanbit no.3, 4, 5, 6 and Hanul no. 3, 4, 5, 6. Their signals are transferred to Plant Monitoring System (PMS) via four Plant Data Acquisition System (PDAS) channels. PMS includes a few application programs like COLSS. In a case that one of 4 PDAS channels fails, COLSS is inoperable. It means that reactor power should be reduced and monitored by CPCS because FSAR of OPR1000 requires that 75% ICIs should be operable. This action can induce transient of reactor core. In order to complement such a trouble, KHNP, KEPCO NF and KEPCO ENC have proposed the way that COLSS can be operable though operable ICIs exist between 60% - 75%. KHNP, KEPCONF and KEPCO ENC have proposed the way that COLSS can be operable though operable ICIs exist between 60% - 75%. Conservatively, the analysis was performed assuming 50% ICIs are inoperable. Though 50% ICIs are inoperable, the power distribution of COLSS is more accurate than that of CPC. The technology was applied to OPR1000s based on above technical background. Shin-Kori no.1, 2 and Shin-Wolsong no.1, 2 are waiting for an application.

  3. Properties of CO2 clathrate hydrates formed in the presence of MgSO4 solutions with implications for icy moons

    Science.gov (United States)

    Safi, E.; Thompson, S. P.; Evans, A.; Day, S. J.; Murray, C. A.; Parker, J. E.; Baker, A. R.; Oliveira, J. M.; van Loon, J. Th.

    2017-04-01

    Context. There is evidence to suggest that clathrate hydrates have a significant effect on the surface geology of icy bodies in the solar system. However the aqueous environments believed to be present on these bodies are likely to be saline rather than pure water. Laboratory work to underpin the properties of clathrate hydrates in such environments is generally lacking. Aims: We aim to fill this gap by carrying out a laboratory investigation of the physical properties of CO2 clathrate hydrates produced in weak aqueous solutions of MgSO4. Methods: We use in situ synchrotron X-ray powder diffraction to investigate clathrate hydrates formed at high CO2 pressure in ice that has formed from aqueous solutions of MgSO4 with varying concentrations. We measure the thermal expansion, density and dissociation properties of the clathrates under temperature conditions similar to those on icy solar system bodies. Results: We find that the sulphate solution inhibits the formation of clathrates by lowering their dissociation temperatures. Hysteresis is found in the thermal expansion coefficients as the clathrates are cooled and heated; we attribute this to the presence of the salt in solution. We find the density derived from X-ray powder diffraction measurements is temperature and pressure dependent. When comparing the density of the CO2 clathrates to that of the solution in which they were formed, we conclude that they should sink in the oceans in which they form. We also find that the polymorph of ice present at low temperatures is Ih rather than the expected Ic, which we tentatively attribute to the presence of the MgSO4. Conclusions: We (1) conclude that the density of the clathrates has implications for their behaviour in satellite oceans as their sinking and floating capabilities are temperature and pressure dependent; (2) conclude that the presence of MgSO4 inhibits the formation of clathrates and in some cases may even affect their structure and (3) report the dominance

  4. Early development of Science Opportunity Analysis tools for the Jupiter Icy Moons Explorer (JUICE) mission

    Science.gov (United States)

    Cardesin Moinelo, Alejandro; Vallat, Claire; Altobelli, Nicolas; Frew, David; Llorente, Rosario; Costa, Marc; Almeida, Miguel; Witasse, Olivier

    2016-10-01

    JUICE is the first large mission in the framework of ESA's Cosmic Vision 2015-2025 program. JUICE will survey the Jovian system with a special focus on three of the Galilean Moons: Europa, Ganymede and Callisto.The mission has recently been adopted and big efforts are being made by the Science Operations Center (SOC) at the European Space and Astronomy Centre (ESAC) in Madrid for the development of tools to provide the necessary support to the Science Working Team (SWT) for science opportunity analysis and early assessment of science operation scenarios. This contribution will outline some of the tools being developed within ESA and in collaboration with the Navigation and Ancillary Information Facility (NAIF) at JPL.The Mission Analysis and Payload Planning Support (MAPPS) is developed by ESA and has been used by most of ESA's planetary missions to generate and validate science observation timelines for the simulation of payload and spacecraft operations. MAPPS has the capability to compute and display all the necessary geometrical information such as the distances, illumination angles and projected field-of-view of an imaging instrument on the surface of the given body and a preliminary setup is already in place for the early assessment of JUICE science operations.NAIF provides valuable SPICE support to the JUICE mission and several tools are being developed to compute and visualize science opportunities. In particular the WebGeoCalc and Cosmographia systems are provided by NAIF to compute time windows and create animations of the observation geometry available via traditional SPICE data files, such as planet orbits, spacecraft trajectory, spacecraft orientation, instrument field-of-view "cones" and instrument footprints. Other software tools are being developed by ESA and other collaborating partners to support the science opportunity analysis for all missions, like the SOLab (Science Operations Laboratory) or new interfaces for observation definitions and

  5. Post main sequence evolution of icy minor planets: water retention and white dwarf pollution

    Science.gov (United States)

    Malamud, Uri; Perets, Hagai

    2017-06-01

    We investigate the evolution of icy minor planets from the moment of their birth and through the all evolutionary stages of their host stars, including the main sequence, red giant branch and asymptotic giant branch phases. We then asses the degree of water retention in planetary systems around white dwarf, as a function of various parameters. We consider progenitor stars of different masses and metallicities. We also consider minor planets of various sizes, initial orbital distances, compositions and formation times. Our results indicate that water can survive to the white dwarf stage in a variety of circumstances, especially around G, F, A and even some B type stars. We discuss the significance of water retention with respect to white dwarf pollution and also for planet habitability.

  6. Looking for the rainbow on exoplanets covered by liquid and icy water clouds

    CERN Document Server

    Karalidi, T; Hovenier, J W

    2012-01-01

    Looking for the primary rainbow in starlight that is reflected by exoplanets appears to be a promising method to search for liquid water clouds in exoplanetary atmospheres. Ice water clouds, that consist of water crystals instead of water droplets, could potentially mask the rainbow feature in the planetary signal by covering liquid water clouds. Here, we investigate the strength of the rainbow feature for exoplanets that have liquid and icy water clouds in their atmosphere, and calculate the rainbow feature for a realistic cloud coverage of Earth. We calculate flux and polarization signals of starlight that is reflected by horizontally and vertically inhomogeneous Earth--like exoplanets, covered by patchy clouds consisting of liquid water droplets or water ice crystals. The planetary surfaces are black. On a planet with a significant coverage of liquid water clouds only, the total flux signal shows a weak rainbow feature. Any coverage of the liquid water clouds by ice clouds, however, dampens the rainbow fea...

  7. Refraction studies between Icy Bay and Kayak Island, eastern Gulf of Alaska

    Science.gov (United States)

    Bayer, K.C.; Mattick, R.E.; Bruns, T.R.; Plafker, George

    1978-01-01

    Results of five seismic refraction lines shot by the U.S. Geological Survey in the Gulf of Alaska between Icy Bay and Kayak Island indicate the following: (1) The Continental Shelf is underlain by as much as 11 km of sedimentary rock of probable Tertiary age where refraction velocities range from 1.2 to 5.5 kilometers per second; (2) a section approximately 5 km thick, which has velocities of 4.1-5.5 km/s and which could represent the Orca Group (lower Tertiary), is present in the western part of the study area but not in the eastern part; and (3) consistent basement velocities of approximately 7.0 km/s could indicate oceanic crust underlying the continental margin.

  8. L’ici-là selon Gisèle Pineau

    Directory of Open Access Journals (Sweden)

    Mariana Ionescu

    2010-05-01

    Full Text Available Cet article porte sur la façon dont l’écrivain antillais Gisèle Pineau entrevoit la possibilité de rapprocher des espaces culturels apparemment irréconciliables par le biais d’un nouvel espace, celui de la remémoration et de l’écriture. Dans cet entre-deux, espace métissé par excellence, les personnages féminins de L’Exil selon Julia, ainsi que ceux d’autres écrits (autobiographiques de Pineau, se confrontent à de nouveaux signes identitaires qui les obligent à jeter un regard critique sur le pays d’accueil, sans pour autant idéaliser à outrance le pays d’origine. Une attention particulière sera attachée au vocable créole ici-là, porteur de significations multiples.

  9. Diagnosis and management of chronic ITP: comments from an ICIS expert group.

    Science.gov (United States)

    Grainger, John David; Bolton-Maggs, Paula H B; Godeau, Bertrand; Bussel, Jim; Donato, Hugo; Elalfy, Mohsen; Hainmann, Ina; Matzdorff, Axel; Müller-Beissenhirtz, Hannes; Rovó, Alicia; Tichelli, Andre

    2010-07-01

    Immune thrombocytopenia (ITP) is a common disorder in children and adults. In a patient with newly diagnosed ITP, the treatment strategy is relatively well defined. Second-line treatments are more controversial, and the management of chronic ITP is even more so. During the 3rd ICIS Expert Meeting on Consensus and Development of Strategies in ITP, held in Basel on September 3-5, 2009, a group of experts were tasked with reaching a consensus on some frequently asked questions relating to diagnosis and management of children and adults with chronic ITP. The content of this article is designed to provide a practical support to trained haematologists in their care of patients with chronic ITP.

  10. Cassini finds an oxygen-carbon dioxide atmosphere at Saturn's icy moon Rhea.

    Science.gov (United States)

    Teolis, B D; Jones, G H; Miles, P F; Tokar, R L; Magee, B A; Waite, J H; Roussos, E; Young, D T; Crary, F J; Coates, A J; Johnson, R E; Tseng, W-L; Baragiola, R A

    2010-12-24

    The flyby measurements of the Cassini spacecraft at Saturn's moon Rhea reveal a tenuous oxygen (O(2))-carbon dioxide (CO(2)) atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn's magnetospheric plasma. This in situ detection of an oxidizing atmosphere is consistent with remote observations of other icy bodies, such as Jupiter's moons Europa and Ganymede, and suggestive of a reservoir of radiolytic O(2) locked within Rhea's ice. The presence of CO(2) suggests radiolysis reactions between surface oxidants and organics or sputtering and/or outgassing of CO(2) endogenic to Rhea's ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism.

  11. Family Portrait of the Small Inner Satellites of Jupiter

    Science.gov (United States)

    1997-01-01

    These images, taken by Galileo's solid state imaging system between November 1996 and June 1997, provide the first ever 'family portrait' of the four small, irregularly shaped moons that orbit Jupiter in the zone between the planet's ring and the larger Galilean satellites. The moons are shown in their correct relative sizes, with north approximately up in all cases. From left to right, arranged in order of increasing distance from Jupiter, are Metis (longest dimension is approximately 60 kilometers or 37 miles across), Adrastea (20 kilometers or 12 miles across), Amalthea (247 kilometers or 154 miles across), and Thebe (116 kilometers or 72 miles across). While Amalthea, the largest of these four tiny moons, was imaged by NASA's two Voyager spacecraft in 1979 with a resolution comparable to what is shown here, the new Galileo observations represent the first time that Metis, Adrastea, and Thebe have been seen as more than points of light.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  12. Photometry and Astrometry of the Jovian satellites Amalthea and Thebe

    Science.gov (United States)

    Saquet, Eléonore; Emelyanov, Nicolai; Colas, François; Robert, Vincent; Arlot, Jean-Eudes

    2016-10-01

    During the 2014-2015 campaign of mutual events, we realized ground-based observations of Amalthea (JV) and Thebe (JXIV). We recorded two eclipses of Amalthea and, for the first time, one of Thebe by the Galilean moons. We used the 1-m telescope at Pic du Midi Observatory with an IR filter and a mask placed over the planetary image to reduce the light intensity of Jupiter. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60-cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. We provide astrometric results derived from the photometry with an overall accuracy of 34 mas, or 100 km at Jupiter.In the same time, we realized 45 astrometric observations of Amalthea and 41 of Thebe to compare the photometric technique with direct astrometry, using the UCAC4 reference star catalog. We provide astrometric results with an overall accuracy of 100 mas for Amalthea, or 300 km at Jupiter, and 90 mas for Thebe, or 270 km at Jupiter. These results are better than those from previous ground-based and old reduced space measurements.

  13. Preclinical evaluation of an {sup 18}F-labelled {beta}{sub 1}-adrenoceptor selective radioligand based on ICI 89,406

    Energy Technology Data Exchange (ETDEWEB)

    Law, Marilyn P. [Department of Nuclear Medicine, University Hospital Muenster, D-48149 Muenster (Germany); European Institute of Molecular Imaging, D-48149 Muenster (Germany)], E-mail: mplaw@uni-muenster.de; Wagner, Stefan; Kopka, Klaus; Renner, Christiane [Department of Nuclear Medicine, University Hospital Muenster, D-48149 Muenster (Germany); Pike, Victor W. [Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1003 (United States); Schober, Otmar [Department of Nuclear Medicine, University Hospital Muenster, D-48149 Muenster (Germany); Schaefers, Michael [European Institute of Molecular Imaging, D-48149 Muenster (Germany)

    2010-05-15

    Purpose: Radioligand binding studies indicate a down-regulation of myocardial {beta}{sub 1}-adrenoceptors ({beta}{sub 1}-AR) in cardiac disease which may or may not be associated with a decrease in {beta}{sub 2}-ARs. We have chosen ICI 89,406, a {beta}{sub 1}-selective AR antagonist, as the lead structure to develop new {beta}{sub 1}-AR radioligands for PET and have synthesised a fluoro-ethoxy derivative (F-ICI). Methods: (S)-N-[2-[3-(2-Cyano-phenoxy)-2-hydroxy-propylamino]-ethyl]-N'-[4-(2-[{sup 18}F] fluoro-ethoxy)-phenyl]-urea ((S)-[{sup 18}F]F-ICI) was synthesised. Myocardial uptake of radioactivity after intravenous injection of (S)-[{sup 18}F]F-ICI into adult CD{sub 1} mice or Wistar rats was assessed with positron emission tomography (PET) and postmortem dissection. Metabolism was assessed by high-performance liquid chromatography analysis of plasma and urine. Results: The heart was visualised with PET after injection of (S)-[{sup 18}F]F-ICI but neither unlabelled F-ICI nor propranolol (non-selective {beta}-AR antagonist) injected 15 min after (S)-[{sup 18}F]F-ICI affected myocardial radioactivity. Ex vivo dissection demonstrated that predosing with propranolol or CGP 20712 ({beta}{sub 1}-selective AR-antagonist) did not affect myocardial radioactivity. Radiometabolites rapidly appeared in plasma and both (S)-[{sup 18}F]F-ICI and radiometabolites accumulated in urine. Conclusions: Myocardial uptake of (S)-[{sup 18}F]F-ICI after intravenous injection was mainly at sites unrelated to {beta}{sub 1}-ARs. (S)-[{sup 18}F]F-ICI is not a suitable {beta}{sub 1}-selective-AR radioligand for PET.

  14. Update of monotherapy trials with the new anti-androgen, Casodex (ICI 176,334). International Casodex Investigators

    DEFF Research Database (Denmark)

    Iversen, P

    1994-01-01

    Casodex (ICI 176,334) is a non-steroidal anti-androgen, which has a half-life compatible with once-daily oral dosing. In an open, phase II study on 267 patients given Casodex, 50 mg/day, an overall objective response (i.e. partial regression) was seen in 55.5% of patients (146 of 263) with a furt...

  15. Formation of Valley Networks in a Cold and Icy Early Mars Climate: Predictions for Erosion Rates and Channel Morphology

    Science.gov (United States)

    Cassanelli, J. P.; Head, J. W.

    2017-10-01

    Climate models suggest early Mars was cold and icy. To test this prediction we assess the influence of cold conditions and the presence of an ice-cemented substrate on the formation of the valley networks and compare results to morphometric data.

  16. Can we identify men who will have complications from benign prostatic obstruction (BPO)? ICI-RS 2011.

    NARCIS (Netherlands)

    Oelke, M.; Kirschner-Hermanns, R.; Thiruchelvam, N.; Heesakkers, J.P.F.A.

    2012-01-01

    AIMS: This ICI-RS report aims to analyze morphological or functional complications of the lower or upper urinary tract in elderly men, clarify the association between complications and benign prostatic obstruction (BPO) and define men who will develop these complications. Research proposals to furth

  17. Impact jetting water ice, with application to the accretion of icy planetesimals and Pluto

    Energy Technology Data Exchange (ETDEWEB)

    McKinnon, W.B. (Washington Univ., Seattle (USA))

    1989-11-01

    Jetting can occur during oblique impacts of water ice bodies at relative velocities at low as {approximately}500 m s{sup {minus}1}, because of the low Hugoniot elastic limit and high compressibility of ice compared to rock. In jetted ice, incipient melting, complete melting, and incipient vaporization occur, upon release to low pressure, at impact velocities of 1.3, 2.0, and 2.7 km s{sup {minus}1}, respectively, much less than the 3.4, 4.4, and 5.3 km s{sup {minus}1} required in head-on collisions. Uncertainties in the shock equation-of-state may allow complete melting during jetting at relative velocities as low as 1.2 km s{sup {minus}1}. Because jet speeds exceed impact speeds, often by a factor of several, during the accretion of icy bodies greater than a few 100 km in radius there any be a significant loss of icy material. This is more true if the accreting body is large enough to differentiate so that its surface layers are closer to pure ice in composition, and especially true if bodies of comparable size are involved, which emphasizes the obliqueness of the collision. The author suggests that it is jetting during a Charon-forming collision (and not vaporization) that may account for Pluto-Charon's relatively large rock/ice ratio, should the C/O ratio of the solar nebula turn out too low to sufficiently raise the rock/ice ratio of outer solar nebula condensates by formation of non-condensable CO.

  18. Water transport to circumprimary habitable zones from icy planetesimal disks in binary star systems

    Science.gov (United States)

    Bancelin, D.; Pilat-Lohinger, E.; Maindl, T. I.; Bazsó, Á.

    2017-03-01

    So far, more than 130 extrasolar planets have been found in multiple stellar systems. Dynamical simulations show that the outcome of the planetary formation process can lead to different planetary architectures (i.e. location, size, mass, and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (HZ). In this study, we make a comparison of several binary star systems and aim to show how efficient they are at moving icy asteroids from beyond the snow line into orbits crossing the HZ. We also analyze the influence of secular and mean motion resonances on the water transport towards the HZ. Our study shows that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result in a more efficient water transport on a short timescale, causing a heavy bombardment. In contrast to asteroids moving under the gravitational perturbations of one G-type star and a gas giant, we show that the presence of a companion star not only favors a faster depletion of our disk of planetesimals, but can also bring 4-5 times more water into the whole HZ. However, due to the secular resonance located either inside the HZ or inside the asteroid belt, impacts between icy planetesimals from the disk and big objects in the HZ can occur at high impact speed. Therefore, real collision modeling using a GPU 3D-SPH code show that in reality, the water content of the projectile is greatly reduced and therefore, also the water transported to planets or embryos initially inside the HZ.

  19. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  20. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  1. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  2. Satellite-Delivered Learning.

    Science.gov (United States)

    Arnall, Gail C.

    1987-01-01

    Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

  3. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  4. China's Recoverable Satellites

    Institute of Scientific and Technical Information of China (English)

    Tang Boehang

    2008-01-01

    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  5. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  6. Stability of orbits around planetary satellites considering a disturbing body in an elliptical orbit: Applications to Europa and Ganymede

    Science.gov (United States)

    Cardoso dos Santos, Josué; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho

    Europa and Ganymede are two of the four Jupiter’s moons which compose the Galilean satellite. These ones are planetary satellites of greater interest at the present moment among the scientific community. There are some missions being planned to visit them and and the Jovian system. One of them is the cooperation between NASA and ESA for the Europa Jupiter System Mission (EJSM). In this mission are planned the insertion of the spacecrafts JEO (Jupiter Europa Orbiter) and JGO (Jupiter Ganymede Orbiter) into Europa and Ganymede’s orbit. Thus, there is a great necessity for having a better comprehension of the dynamics of the orbits around this planetary satellite. This comprehension is essential for the success of this type of mission. In this context, this work aims to perform a search for low-altitude orbits around these planetary satellites. An emphasis is given in polar orbits. These orbits can be useful in the planning of aerospace activities to be conducted around this planetary satellite, with respect to the stability of orbits of artificial satellites. The study considers orbits of an artificial satellite around Europa and Ganymede under the influence of the third-body perturbation (the gravitational attraction of Jupiter) and the polygenic perturbations. These last ones occur due to forces such as the non-uniform distribution of mass (J2 and J3) of the main (central) body. A simplified dynamic model for polygenic perturbations is used. A new model for the third-body disturbance is presented considering it in an elliptical orbit. The Lagrange planetary equations, which compose a system of nonlinear differential equations, are used to describe the orbital motion of the artificial satellite around Ganymede. The equations showed here are developed in closed form to avoid expansions in inclination and eccentricity.

  7. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  8. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  9. Geodetic Secor Satellite

    Science.gov (United States)

    1974-06-01

    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  10. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  11. Are [O-methyl-{sup 11}C]derivatives of ICI 89,406 {beta}{sub 1}-adrenoceptor selective radioligands suitable for PET?

    Energy Technology Data Exchange (ETDEWEB)

    Law, Marilyn P.; Wagner, Stefan; Kopka, Klaus; Schober, Otmar; Schaefers, Michael [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Pike, Victor W. [National Institutes of Health, Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD (United States)

    2008-01-15

    Radioligand binding studies show that {beta}{sub 1}-adrenoceptor ({beta}{sub 1}-AR) density may be reduced in heart disease without down regulation of {beta}{sub 2}-ARs. Radioligands are available for measuring total {beta}-AR density non-invasively with clinical positron emission tomography (PET) but none are selective for {beta}{sub 1}- or {beta}{sub 2}-ARs. The aim was to evaluate ICI 89,406, a {beta}{sub 1}-AR-selective antagonist amenable to labelling with positron emitters, for PET. The S-enantiomer of an [O-methyl-{sup 11}C] derivative of ICI 89,406 ((S)-[{sup 11}C]ICI-OMe) was synthesised. Tissue radioactivity after i.v. injection of (S)-[{sup 11}C]ICI-OMe (< 2 nmol.kg{sup -1}) into adult Wistar rats was assessed by small animal PET and post mortem dissection. Metabolism was assessed by HPLC of extracts prepared from plasma and tissues and by measuring [{sup 11}C]CO{sub 2} in exhaled air. The heart was visualised by PET after injection of (S)-[{sup 11}C]ICI-OMe but neither unlabelled (S)-ICI-OMe nor propranolol (non-selective {beta}-AR antagonist) injected 15 min after (S)-[{sup 11}C]ICI-OMe affected myocardial radioactivity. Ex vivo dissection showed that injecting unlabelled (S)-ICI-OMe, propranolol or CGP 20712A ({beta}{sub 1}-selective AR antagonist) at high dose (> 2 {mu}mol.kg{sup -1}) before (S)-[{sup 11}C]ICI-OMe had a small effect on myocardial radioactivity. HPLC demonstrated that radioactivity in myocardium was due to unmetabolised (S)-[{sup 11}C]ICI-OMe although {sup 11}C-labelled metabolites rapidly appeared in plasma and liver and [{sup 11}C]CO{sub 2} was detected in exhaled air. Myocardial uptake of (S)-[{sup 11}C]ICI-OMe after i.v. injection was low, possibly due to rapid metabolism in other tissues. Injection of unlabelled ligand or {beta}-AR antagonists had little effect indicating that binding was mainly to non-specific myocardial sites, thus precluding the use of (S)-[{sup 11}C]ICI-OMe to assess {beta}{sub 1}-ARs with PET. (orig.)

  12. Overview of the Project Prometheus Program

    Science.gov (United States)

    Burdick, G. M.

    2003-01-01

    This presentation will give an overview of the Project Prometheus Program (PPP, formerly the Nuclear Systems Initiative, NSI) and the Jupiter Icy Moons Orbiter (JIMO) Project (a component of PPP), a mission to the three icy Galilean moons of Jupiter.

  13. Physical Properties of the Icy Soil at the Phoenix Landing Site

    Science.gov (United States)

    Keller, H.; Markiewicz, W. J.; Hviid, S. F.; Goetz, W.; Mellon, M. T.; El Maarry, M.; Madsen, M. B.; Smith, P.; Pike, W.; Zent, A.; Hecht, M. H.; Ming, D.; Staufer, U.

    2008-12-01

    The geomorphological setting of the subpolar terrain at the landing site is characterized by polygonal structures. These structures are generated by long term and periodic cycles of contraction and expansion of the subsurface icy soil. The physical properties of the covering soil layer effectively control the details of this process that has its counterpart on earth in (sub) polar regions including the Siberian tundra and in Antartica. One of the prime science goals of the Phoenix mission is to investigate the physical properties of the icy soil, how these processes are influenced by water vapour diffusion in the regolith and exchange of the water vapour with the atmosphere. It is important to understand these processes on diurnal, seasonal, and climatic time scales. Phoenix landed in the middle of one of the polygons. Its retro rockets cleared the ice table of the polygon underneath the jet assemblies from ca. 5 to 10 cm of loose cloddy regolith. Soil was piled up in the centre. The fact that the soil looked still cloddy similar to that in undisturbed areas suggests strong cohesiveness of the matrix material. The clumps were not destroyed by the blast. Excavated regolith material imaged in the scoop was made up of agglomerates of grains smaller than the best resolution of the Robotic Arm Camera (20 micron). Higher resolution images (4 micron) of the microscope corroborate that the soil is predominantly composed of agglomerates of very small particles with a mean size comparable to those observed in the Martian atmosphere. The Atomic Force Microscope reveals micron sized particles and smaller, partly of plate-like shape, indicating clay like particles. The matrix material of the soil is of reddish colour probably due to iron oxideadmixture. Only about 10% by volume of the soil are most often rounded grains between 40 to 100 micrometers of diameter. Some are glassy resembling micro tektites, and most of these are magnetic. The cohesiveness of the clumps and clods of

  14. Heat transport in the high-pressure ice mantle of large icy moons

    Science.gov (United States)

    Choblet, G.; Tobie, G.; Sotin, C.; Kalousová, K.; Grasset, O.

    2017-03-01

    While the existence of a buried ocean sandwiched between surface ice and high-pressure (HP) polymorphs of ice emerges as the most plausible structure for the hundreds-of-kilometers thick hydrospheres within large icy moons of the Solar System (Ganymede, Callisto, Titan), little is known about the thermal structure of the deep HP ice mantle and its dynamics, possibly involving melt production and extraction. This has major implications for the thermal history of these objects as well as on the habitability of their ocean as the HP ice mantle is presumed to limit chemical transport from the rock component to the ocean. Here, we describe 3D spherical simulations of subsolidus thermal convection tailored to the specific structure of the HP ice mantle of large icy moons. Melt production is monitored and melt transport is simplified by assuming instantaneous extraction to the ocean above. The two controlling parameters for these models are the rheology of ice VI and the heat flux from the rock core. Reasonable end-members are considered for both parameters as disagreement remains on the former (especially the pressure effect on viscosity) and as the latter is expected to vary significantly during the moon's history. We show that the heat power produced by radioactive decay within the rock core is mainly transported through the HP ice mantle by melt extraction to the ocean, with most of the melt produced directly above the rock/water interface. While the average temperature in the bulk of the HP ice mantle is always relatively cool when compared to the value at the interface with the rock core (∼ 5 K above the value at the surface of the HP ice mantle), maximum temperatures at all depths are close to the melting point, often leading to the interconnection of a melt path via hot convective plume conduits throughout the HP ice mantle. Overall, we predict long periods of time during these moons' history where water generated in contact with the rock core is transported to

  15. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  16. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  17. The Saturnian satellite Rhea as seen by Cassini VIMS

    Science.gov (United States)

    Stephan, K.; Jaumann, R.; Wagner, R.; Clark, R.N.; Cruikshank, D.P.; Giese, B.; Hibbitts, C.A.; Roatsch, T.; Matz, K.-D.; Brown, R.H.; Filacchione, G.; Cappacioni, F.; Scholten, F.; Buratti, B.J.; Hansen, G.B.; Nicholson, P.D.; Baines, K.H.; Nelson, R.M.; Matson, D.L.

    2012-01-01

    Since the arrival of the Cassini spacecraft at Saturn in June 2004, the Visual and Infrared Mapping Spectrometer has obtained new spectral data of the icy satellites of Saturn in the spectral range from 0.35 to 5.2 ??m. Numerous flybys were performed at Saturn's second largest satellite Rhea, providing a nearly complete coverage with pixel-ground resolutions sufficient to analyze variations of spectral properties across Rhea's surface in detail. We present an overview of the VIMS observations obtained so far, as well as the analysis of the spectral properties identified in the VIMS spectra and their variations across its surface compared with spatially highly resolved Cassini ISS images and digital elevation models. Spectral variations measured across Rhea's surface are similar to the variations observed in the VIMS observations of its neighbor Dione, implying similar processes causing or at least inducing their occurrence. Thus, magnetospheric particles and dust impacting onto the trailing hemisphere appear to be responsible for the concentration of dark rocky/organic material and minor amounts of CO 2 in the cratered terrain on the trailing hemisphere. Despite the prominent spectral signatures of Rhea's fresh impact crater Inktomi, radiation effects were identified that also affect the H 2O ice-rich cratered terrain of the leading hemisphere. The concentration of H 2O ice in the vicinity of steep tectonic scarps near 270??W and geologically fresh impact craters implies that Rhea exhibits an icy crust at least in the upper few kilometers. Despite the evidence for past tectonic events, no indications of recent endogenically powered processes could be identified in the Cassini data. ?? 2011 Elsevier Ltd. All rights reserved.

  18. Comparison of "warm and wet" and "cold and icy" scenarios for early Mars in a 3D climate model

    CERN Document Server

    Wordsworth, Robin D; Pierrehumbert, Raymond T; Forget, Francois; Head, James W

    2015-01-01

    We use a 3D general circulation model to compare the primitive Martian hydrological cycle in "warm and wet" and "cold and icy" scenarios. In the warm and wet scenario, an anomalously high solar flux or intense greenhouse warming artificially added to the climate model are required to maintain warm conditions and an ice-free northern ocean. Precipitation shows strong surface variations, with high rates around Hellas basin and west of Tharsis but low rates around Margaritifer Sinus (where the observed valley network drainage density is nonetheless high). In the cold and icy scenario, snow migration is a function of both obliquity and surface pressure, and limited episodic melting is possible through combinations of seasonal, volcanic and impact forcing. At surface pressures above those required to avoid atmospheric collapse (~0.5 bar) and moderate to high obliquity, snow is transported to the equatorial highland regions where the concentration of valley networks is highest. Snow accumulation in the Aeolis quadr...

  19. Distribution of icy particles across Enceladus' surface as derived from Cassini-VIMS measurements

    Science.gov (United States)

    Jaumann, R.; Stephan, K.; Hansen, G.B.; Clark, R.N.; Buratti, B.J.; Brown, R.H.; Baines, K.H.; Newman, S.F.; Bellucci, G.; Filacchione, G.; Coradini, A.; Cruikshank, D.P.; Griffith, C.A.; Hibbitts, C.A.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sotin, Christophe; Wagner, R.

    2008-01-01

    The surface of Enceladus consists almost completely of water ice. As the band depths of water ice absorptions are sensitive to the size of particles, absorptions can be used to map variations of icy particles across the surface. The Visual and Infrared Mapping Spectrometer (VIMS) observed Enceladus with a high spatial resolution during three Cassini flybys in 2005 (orbits EN 003, EN 004 and EN 011). Based on these data we measured the band depths of water ice absorptions at 1.04, 1.25, 1.5, and 2 ??m. These band depths were compared to water ice models that represent theoretically calculated reflectance spectra for a range of particle diameters between 2 ??m and 1 mm. The agreement between the experimental (VIMS) and model values supports the assumption that pure water ice characterizes the surface of Enceladus and therefore that variations in band depth correspond to variations in water ice particle diameters. Our measurements show that the particle diameter of water ice increases toward younger tectonically altered surface units with the largest particles exposed in relatively "fresh" surface material. The smallest particles were generally found in old densely cratered terrains. The largest particles (???0.2 mm) are concentrated in the so called "tiger stripes" at the south pole. In general, the particle diameters are strongly correlated with geologic features and surface ages, indicating a stratigraphic evolution of the surface that is caused by cryovolcanic resurfacing and impact gardening. ?? 2007 Elsevier Inc. All rights reserved.

  20. Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

    Directory of Open Access Journals (Sweden)

    Philippe Boduch

    2011-01-01

    Full Text Available Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc. of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

  1. Feasibility Study of Jupiter Icy Moons Orbiter Permanent Magnet Alternator Start Sequence

    Science.gov (United States)

    Kenny, Barbara H.; Tokars, Roger P.

    2006-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission was a proposed, (recently cancelled) long duration science mission to study three moons of Jupiter: Callisto, Ganymede, and Europa. One design of the JIMO spacecraft used a nuclear heat source in conjunction with a Brayton rotating machine to generate electrical power for the electric thrusters and the spacecraft bus. The basic operation of the closed cycle Brayton system was as follows. The working fluid, a heliumxenon gas mixture, first entered a compressor, then went through a recuperator and hot-side heat exchanger, then expanded across a turbine that drove an alternator, then entered the cold-side of the recuperator and heat exchanger and finally returned to the compressor. The spacecraft was to be launched with the Brayton system off-line and the nuclear reactor shut down. Once the system was started, the helium-xenon gas would be circulated into the heat exchangers as the nuclear reactors were activated. Initially, the alternator unit would operate as a motor so as to drive the turbine and compressor to get the cycle started. This report investigated the feasibility of the start up sequence of a permanent magnet (PM) machine, similar in operation to the alternator unit, without any position or speed feedback sensors ("sensorless") and with a variable load torque. It is found that the permanent magnet machine can start with sensorless control and a load torque of up to 30 percent of the rated value.

  2. Sublimation of Icy Planetesimals Around Main Sequence Stars--Common Dust Temperatures & Multiple Components

    Science.gov (United States)

    Morales, Farisa Y.; Rieke, G.; Werner, M.; Su, K.; Bryden, G.; Stapelfeldt, K.

    2011-01-01

    We compare the properties of warm dust emission from main-sequence A-type stars to those of dust around solar-type sources with similar Spitzer Space Telescope IRS/MIPS data and similar ages. Both samples have spectral energy distributions which show evidence of multiple components. Over the range of stellar types considered, we obtain nearly the same characteristic dust temperatures ( 190 K & 55 K for the inner & outer dust components respectively)--just above the ice line for the inner belts. The inner-belt temperature is readily explained if populations of grains are being released by sublimation of ice from icy planetesimals. Evaporation of comets at 170 K transports particles into an inner/warmer belt, where the super thermal grains left behind are found with Tdust >=190 K. 27 of the 50 A-type sources with warm excess are detected with Spitzer/MIPS at 70 µm (S/N > 3); the 50% rate of detection is comparable to the solar-type star sample where 9 of the 19 objects are also seen at MIPS 70 µm. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Development of MIPS was funded by NASA through the Jet Propulsion Laboratory, subcontract 960785. This work was also partially supported by contract 1255094 from Caltech/JPL to the University of Arizona.

  3. Considerations for a Radar System to Detect an Ocean Underneath the Icy Shell of Europa

    Science.gov (United States)

    Markus, Thorsten; Gogineni, Prasad; Green, James; Cooper, John; Fung, Shing; Taylor, William; Benson, Robert; Reinisch, Bodo; Song, Paul

    2004-01-01

    The detection of an ocean underneath Europa is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. An orbiting surface penetrating radar has the potential of providing that measurement thus yielding information regarding the possibility of life support on Europa. Radars in the MHz range have successfully monitored the kilometer-deep ice shelves of Greenland and Antarctica, including the detection of Lake Vostok (and others) below an ice sheet thickness of about 4 km. The performance of a radar system orbiting Europa will be subject to several potential complications and unknowns. Besides ionospheric dispersion and the actual depth of the ocean, which is estimated between 2 and 30 km, major unknowns affecting radar performance are the temperature profile, the amount of salt and other impurities within the ice crust as well as the surface roughness. These impurities can in part be produced at the highly irradiated surface by magnetospheric interactions and transported downward into the ice crust by geologic processes. The ionospheric interference must also be modeled from effects of these interactions on production of the thin neutral atmosphere and subsequent ionization of the neutrals. We investigated these uncertainties through radar simulations using different surface and ice characteristics over a frequency range from 10 to 50 MHz. The talk will present results from these simulations discussing potential limitations.

  4. Firn densification in a Late Noachian “icy highlands” Mars: Implications for ice sheet evolution and thermal response

    Science.gov (United States)

    Cassanelli, James P.; Head, James W.

    2015-06-01

    Recent modeling of a thicker early CO2 martian atmosphere and Late Noachian climate predicts that for pressures beyond a fraction of a bar, atmosphere-surface thermal coupling occurs, resulting in adiabatic cooling of high areas across Mars. This promotes the transport of water ice from relatively warmer low-lying areas to the highlands, where deposition and accumulation of water ice result in an "icy highlands" Late Noachian Mars. Deposits will remain stable in the highlands under nominal Late Noachian conditions, but the potential exists for punctuated heating by both top-down (e.g. impacts, volcanism) and bottom-up (e.g. elevated geothermal heat flux) processes. Important in understanding melt generation from these processes is the state of the accumulated snow and ice. Through modeling of the firn densification process in the "icy highlands" framework we assess: (1) the nature of snow accumulation and the physical growth and evolution of the predicted ice deposits, and (2) the implications for the thermal properties of the ice sheets and the response to heating events. Analysis of the firn densification process in the "icy highlands" context indicates that: (1) the upper layers of the ice sheet will be more vulnerable to melting from top-down heating processes because they are comprised of the least dense and least thermally conductive ice, and (2) even with a low thermal conductivity firn layer, basal melting is only likely to occur through a combination of top-down and bottom-up heating. This is because at the nominal mean annual surface temperatures and estimated effective thermal conductivities, the predicted ice sheet thicknesses do not produce enough basal warming to initiate melting for plausible geothermal heat fluxes. Variations in spin-axis/orbital parameters alone are not predicted to cause widespread ablation (melting and sublimation) of the icy highlands ice sheets.

  5. Theoretical calculation on ICI reduction using digital coherent superposition of optical OFDM subcarrier pairs in the presence of laser phase noise.

    Science.gov (United States)

    Yi, Xingwen; Xu, Bo; Zhang, Jing; Lin, Yun; Qiu, Kun

    2014-12-15

    Digital coherent superposition (DCS) of optical OFDM subcarrier pairs with Hermitian symmetry can reduce the inter-carrier-interference (ICI) noise resulted from phase noise. In this paper, we show two different implementations of DCS-OFDM that have the same performance in the presence of laser phase noise. We complete the theoretical calculation on ICI reduction by using the model of pure Wiener phase noise. By Taylor expansion of the ICI, we show that the ICI power is cancelled to the second order by DCS. The fourth order term is further derived out and only decided by the ratio of laser linewidth to OFDM subcarrier symbol rate, which can greatly simplify the system design. Finally, we verify our theoretical calculations in simulations and use the analytical results to predict the system performance. DCS-OFDM is expected to be beneficial to certain optical fiber transmissions.

  6. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  7. Satellite communication antenna technology

    Science.gov (United States)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  8. Methods of satellite oceanography

    Science.gov (United States)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  9. Laboratory permittivity measurements of icy planetary analogs in the millimeter and submillimeter domains, in relation with JUICE mission.

    Science.gov (United States)

    Brouet, Y.; Jacob, K.; Murk, A.; Poch, O.; Pommerol, A.; Thomas, N.; Levasseur-Regourd, A. C.

    2015-12-01

    The European Space Agency's JUpiter ICy moons Explorer (JUICE) spacecraft is planned for launch in 2022 and arrival at Jupiter in 2030. It will observe the planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. One instrument on the JUICE spacecraft is the Sub-millimeter Wave Instrument (SWI), which will measure brightness temperatures from Jupiter's stratosphere and troposphere, and from subsurfaces of Jupiter's icy moons. In the baseline configuration SWI consists of two tunable sub-millimeter wave receivers operating from 530 to 625 GHz. As an alternative one of the receivers could cover the range of 1080 and 1275 GHz. Inversion models are strongly dependent on the knowledge of the complex relative permittivity (hereafter permittivity) of the target material to retrieve the physical properties of the subsurface (e.g. [1][2]). We set up a laboratory experiment allowing us to perform reproducible measurements of the complex scattering parameters S11 and S21 in the ranges of 70 to 110 GHz, of 100 to 160 GHz, of 140 to 220 GHz, of 140 to 220 GHz and of 510 to 715 GHz. These scattering parameters can be used to retrieve the permittivity of icy analogs of the surfaces and subsurfaces of Jupiter's icy moons in order to prepare the data interpretation of SWI [3]. The measurements are performed under laboratory conditions with a quasi-optical bench (Institute of Applied Physics, University of Bern). The icy analogs that we prepare in the Laboratory for Outflow Studies of Sublimating Materials (LOSSy, Physics Institute, University of Bern), include two different porous water ice samples composed of fine-grained ice particles with a size range of 4 to 6 microns and ice particles with a size range of 50 to 100 microns [4][5]; and possibly CO2 ice. We will present the general experimental set-up and the first results in the context to prepare the data interpretation of SWI. [1] Ulaby, F. T., Long, D. G., 2014. Microwave radar and radiometric remote

  10. Remote Sensing of Potential Biosignatures from Rocky, Liquid, or Icy (Exo)Planetary Surfaces

    Science.gov (United States)

    Poch, Olivier; Frey, Joachim; Roditi, Isabel; Pommerol, Antoine; Jost, Bernhard; Thomas, Nicolas

    2017-03-01

    To detect signs of life by remote sensing on objects of our Solar System and on exoplanets, the characterization of light scattered by surface life material could complement possible clues given by the atmospheric composition. We reviewed the reflectance spectra of a broad selection of major biomolecules that constitute terrestrial carbon-based life from 0.4 to 2.4 μm, and we discuss their detectability through atmospheric spectral windows. Biomolecule features in the near-infrared (0.8-2.4 μm) will likely be obscured by water spectral features and some atmospheric gases. The visible range (0.4-0.8 μm), including the strong spectral features of pigments, is the most favorable. We investigated the detectability of a pigmented microorganism (Deinococcus radiodurans) when mixed with silica sand, liquid water, and water-ice particles representative of diverse surfaces of potentially habitable worlds. We measured the visible to near-infrared reflectance spectra (0.4-2.4 μm) and the visible phase curves (at 0.45 and 0.75 μm) of the mixtures to assess how the surface medium and the viewing geometry affect the detectability of the microorganisms. The results show that ice appears to be the most favorable medium for the detection of pigments. Water ice is bright and featureless from 0.4 to 0.8 μm, allowing the absorption of any pigment present in the ice to be well noticeable. We found that the visible phase curve of water ice is the most strongly affected by the presence of pigments, with variations of the spectral slope by more than a factor of 3 with phase angles. Finally, we show that the sublimation of the ice results in the concentration of the biological material onto the surface and the consequent increase of its signal. These results have applications to the search for life on icy worlds, such as Europa or Enceladus.

  11. Looking for the rainbow on exoplanets covered by liquid and icy water clouds

    Science.gov (United States)

    Karalidi, T.; Stam, D. M.; Hovenier, J. W.

    2012-12-01

    Aims: Looking for the primary rainbow in starlight that is reflected by exoplanets appears to be a promising method to search for liquid water clouds in exoplanetary atmospheres. Ice water clouds, that consist of water crystals instead of water droplets, could potentially mask the rainbow feature in the planetary signal by covering liquid water clouds. Here, we investigate the strength of the rainbow feature for exoplanets that have liquid and icy water clouds in their atmosphere, and calculate the rainbow feature for a realistic cloud coverage of Earth. Methods: We calculate flux and polarization signals of starlight that is reflected by horizontally and vertically inhomogeneous Earth-like exoplanets, covered by patchy clouds consisting of liquid water droplets or water ice crystals. The planetary surfaces are black. Results: On a planet with a significant coverage of liquid water clouds only, the total flux signal shows a weak rainbow feature. Any coverage of the liquid water clouds by ice clouds, however, dampens the rainbow feature in the total flux, and thus the discovery of liquid water in the atmosphere. On the other hand, detecting the primary rainbow in the polarization signal of exoplanets appears to be a powerful tool for detecting liquid water in exoplanetary atmospheres, even when these clouds are partially covered by ice clouds. In particular, liquid water clouds covering as little as 10-20% of the planetary surface, with more than half of these covered by ice clouds, still create a polarized rainbow feature in the planetary signal. Indeed, calculations of flux and polarization signals of an exoplanet with a realistic Earth-like cloud coverage, show a strong polarized rainbow feature.

  12. Non-uniform thickness in Europa's icy shell: implications for astrobiology mission design

    Science.gov (United States)

    Fairén, A.; Amils, R.

    The exploration of Europa's subsurface ocean is hardly constrained by the presence of an outer ice shell of unknown thickness: a somewhat thin crust would allow easier access to the ocean below. Current estimates for the thickness of Europa's icy surface range from a few km [1] to a few tens of km [2], the shell overlying a liquid water ocean up to 150 km thick [3,4,5]. The surface is believed to be young (mean age of 30-80 Myr [6]) and geologically active [7,8,9], as it is sparsely cratered. Here we report geological evidence indicating that the thickness of Europa's ice crust is actually a complex combination of thicker and thinner areas, highlighting the implications of such structure in the future exploration of the inner ocean. Detailed geologic mapping of impact craters, palimpsests and chaotic terrains distribution on Europa's surface, offers an initial approach to a comprehensive description of the thickness variation in the ice shell. Our analysis is based in: (1) Crater distribution, morphology, diameter and depth. Seminal work by Schenk [2] of transitions in crater shape/diameter suggested enhanced structural collapse of craters with diameter >27-33 km, that will consequently form multiring basins, due to weaker ice or a global ocean at depths >19-25 km. This being true, strictly can only be interpreted regionally: multiring basins indicate regions where the ice shell is thick; in those regions where the icy surface is thin, a bolide impact will breach the ice and leave neither crater nor multiring basin behind, but probably Ganymede's type palimpsests. (2) Palimpsest-type features distribution, indicating regions where the ice shell is too thin to support crater formation after big bolide impacts. In Ganymede, palimpsests are circular, low albedo and relief features formerly formed by impacts [10,11]. (3) Chaotic terrain distribution, considering features tens to hundreds of km across, that may be the evidence for very thin ice areas (from ˜ 2 km to

  13. Satellites of spiral galaxies

    Science.gov (United States)

    Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

    1993-01-01

    We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

  14. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  15. Elastic thickness and heat flux estimates for the uranian satellite Ariel

    Science.gov (United States)

    Peterson, G.; Nimmo, F.; Schenk, P.

    2015-04-01

    The surface of Ariel, an icy satellite orbiting Uranus, shows extensional tectonic features suggesting an episode of endogenic heating in the satellite's past. Using topography derived from stereo-photoclinometry, we identified flexural uplift at a rift zone suggesting elastic thickness values in the range 3.8-4.4 km. We estimate the temperature at the base of the lithosphere to be in the range 99-146 K, depending on the strain rate assumed, with corresponding heat fluxes of 28-92 mW/m2. Neither tidal heating, assuming Ariel's current eccentricity, nor radiogenic heat production from the silicate core are enough to cause the inferred heat fluxes. None of three proposed ancient mean-motion resonances produce equilibrium tidal heating values in excess of 4.3 mW/m2. Thus, the origin of the inferred high heat fluxes is currently mysterious.

  16. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  17. Development and Testing of a Laser-Powered Cryobot for Outer Planet Icy Moon Exploration

    Science.gov (United States)

    Siegel, V.; Stone, W.; Hogan, B.; Lelievre, S.; Flesher, C.

    2013-12-01

    Project VALKYRIE (Very-deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer) is a NASA-funded effort to develop the first laser powered cryobot - a self-contained intelligent ice penetrator capable of delivering science payloads through ice caps of the outer planet icy moons. The long range objective is to enable a full-scale Europa lander mission in which an autonomous life-searching underwater vehicle is transported by the cryobot and launched into the sub-surface Europan ocean. Mission readiness testing will involve an Antarctic sub-glacial lake cryobot sample return through kilometers of ice cap thickness. A key element of VALKYRIE's design is the use of a high energy laser as the primary power source. 1070 nm laser light is transmitted at a power level of 5 kW from a surface-based laser and injected into a custom-designed optical waveguide that is spooled out from the descending cryobot. Light exits the downstream end of the fiber, travels through diverging optics, and strikes a beam dump, which channels thermal power to hot water jets that melt the descent hole. Some beam energy is converted, via photovoltaic cells, to electricity for running onboard electronics and jet pumps. Since the vehicle can be sterilized prior to deployment and the melt path freezes behind it, preventing forward contamination, expansions on VALKYRIE concepts may enable cleaner and faster access to sub-glacial Antarctic lakes. Testing at Stone Aerospace between 2010 and 2013 has already demonstrated high power optical energy transfer over relevant (kilometer scale) distances as well as the feasibility of a vehicle-deployed optical waveguide (through which the power is transferred). The test vehicle is equipped with a forward-looking synthetic aperture radar (SAR) that can detect obstacles out to 1 kilometer from the vehicle. The initial ASTEP test vehicle will carry a science payload consisting of a DUV flow cytometer and a water sampling sub-system that will be

  18. Status of the Ganymede Laser Altimeter (GALA) for ESA's Jupiter Icy Moons Explorer (JUICE)

    Science.gov (United States)

    Hussmann, Hauke; Luedicke, Fabian

    2017-04-01

    The Ganymede Laser Altimeter (GALA) is one of the instruments selected for ESA's Jupiter Icy Moons Explorer (JUICE). A fundamental goal of any exploratory space mission is to characterize and measure the shape, topography, and rotation of the target bodies. A state of the art tool for this task is laser altimetry because it can provide absolute topographic height and position with respect to a body centered reference system. With respect to Ganymede, the GALA instrument aims at mapping of global, regional and local topography; confirming the global subsurface ocean and further characterization of the water-ice/liquid shell by monitoring the dynamic response of the ice shell to tidal forces; providing constraints on the forced physical librations and spin-axis obliquity; determining Ganymede's shape; obtaining detailed topographic profiles across the linear features of grooved terrain, impact structures, possible cryo-volcanic features and other different surface units; providing information about slope, roughness and albedo (at 1064nm) of Ganymede's surface. After several flyby's (Ganymede, Europa, Callisto) it is scheduled that the JUICE orbiter will enter first into an elliptical orbit (200 km x 10.000 km) for around 150 days and then into a circular orbit (500 km) around Ganymede for 130 days. Accordingly to the different orbits and trajectories, distances to the moons respectively, the spot size of the GALA laser varies between 21 m and 140 m. GALA uses the direct-detection (classical) approach of laser altimetry. Laser pulses are emitted at a wavelength of 1064 nm by using an actively Q-switched Nd:Yag laser. The pulse energy and pulse repetition frequency are 17 mJ at 30 Hz (nominal), respectively. For targeted observations and flybys the frequency can be switched to 50 Hz. The emission time of each pulse is measured by the detector. The beam is reflected from the surface and received at a 25 cm diameter telescope. The returning laser pulse is refocused onto

  19. High-Power Radar Sounders for the Investigation of Jupiter Icy Moons

    Science.gov (United States)

    Safaeinili, A.; Ostro, S.; Rodriquez, E.; Blankenship, D.; Kurth, W.; Kirchner, D.

    2005-01-01

    The high power and high data rate capability made available by a Prometheus class spacecraft could significantly enhance our ability to probe the subsurface of the planets/moons and asteroid/comets. The main technology development driver for our radar is the proposed Jupiter Icy Moon Orbiter (or JIMO) mission due to its harsh radiation environment. We plan to develop a dual-band radar at 5 and 50 MHz in response to the two major science requirements identified by the JIMO Science Definition Team: studying the near subsurface (less than 2 km) at high resolution and detection of the ice/ocean interface for Europa (depth up to 30 km). The 50-MHz band is necessary to provide high spatial resolution (footprint and depth) as required by the JIMO mission science requirements as currently defined. Our preliminary assessment indicates that the 50-MHz system is not required to be as high-power as the 5-MHz system since it will be more limited by the surface clutter than the Jupiter or galactic background noise. The low frequency band (e.g. 5 MHz), which is the focus of this effort, would be necessary to mitigate the performance risks posed by the unknown subsurface structure both in terms of unknown attenuation due to volumetric scattering and also the detection of the interface through the attenuative transition region at the ice/ocean interface. Additionally, the 5-MHz band is less affected by the surface roughness that can cause loss of coherence and clutter noise. However, since the Signal-to-Noise-Ratio (SNR) of the 5-MHz radar band is reduced due to Jupiter noise when operating in the Jupiter side of the moon, it is necessary to increase the radiated power. Our challenge is to design a high-power HF radar that can hnction in Jupiter's high radiation environment, yet be able to fit into spacecraft resource constraints such as mass and thermal limits. Our effort to develop the JIMO radar sounder will rely on our team's experience with planetary radar sounder design

  20. Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)

    Science.gov (United States)

    Papa, Melissa R.

    2004-01-01

    Around the year 2011, the Jupiter Icy Moons Orbiter (JIMO) will be launched and on its way to orbit three of Jupiter s planet-sized moons. The mission goals for the JIMO project revolve heavily around gathering scientific data concerning ingredients we, as humans, consider essential: water, energy and necessary chemical elements. The JIM0 is an ambitious mission which will implore propulsion from an ION thruster powered by a nuclear fission reactor. Glenn Research Center is responsible for the development of the dynamic power conversion, power management and distribution, heat rejection and ION thrusters. The first test phase for the JIM0 program concerns the High Power AC Power Management and Distribution (PMAD) Test Bed. The goal of this testing is to support electrical performance verification of the power systems. The test bed will incorporate a 2kW Brayton Rotating Unit (BRU) to simulate the nuclear reactor as well as two ION thrusters. The first module of the PMAD Test Bed to be designed is the Main Power Distribution Unit (MPDU) which relays the power input to the various propulsion systems and scientific instruments. The MPDU involves circuitry design as well as mechanical design to determine the placement of the components. The MPDU consists of fourteen relays of four different variations used to convert the input power into the appropriate power output. The three phase system uses 400 Vo1ts(sub L-L) rms at 1000 Hertz. The power is relayed through the circuit and distributed to the scientific instruments, the ION thrusters and other controlled systems. The mechanical design requires the components to be positioned for easy electrical wiring as well as allowing adequate room for the main buss bars, individual circuit boards connected to each component and power supplies. To accomplish creating a suitable design, AutoCAD was used as a drafting tool. By showing a visual layout of the components, it is easy to see where there is extra room or where the

  1. Laser-driven shock experiments in pre-compressed water: Implications for magnetic field generation in Icy Giant planets

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K; Benedetti, L R; Jeanloz, R; Celliers, P M; Eggert, J H; Hicks, D G; Moon, S J; Mackinnon, A; Henry, E; Koenig, M; Benuzzi-Mounaix, A; Collins, G W

    2005-11-10

    Laser-driven shock compression of pre-compressed water (up to 1 GPa precompression) produces high-pressure, -temperature conditions in the water inducing two optical phenomena: opacity and reflectivity in the initially transparent water. The onset of reflectivity at infrared wavelengths can be interpreted as a semi-conductor to electronic conductor transition in water and is found at pressures above {approx}130 GPa for single-shocked samples pre-compressed to 1 GPa. This electronic conduction provides an additional contribution to the conductivity required for magnetic field generation in Icy Giant planets like Uranus and Neptune.

  2. The near-equilibrium figure of the dwarf planet Haumea and possible mechanism of origin of its satellites

    Science.gov (United States)

    Kondratyev, B. P.

    2016-05-01

    The purpose of this paper consists in constructing the near-equilibrium model of the dwarf planet Haumea and developing the latent mechanism of accumulation of icy masses at sharp ends of the rapidly rotating planet. The model can be introduced by combining the ellipsoidal stone core with confocal icy shell and represents a non-uniform figure of rotating gravitating mass with superficial tension from the icy layer. We thoroughly study its dynamic properties and achieve that the gravitational potential on an external and intermediate (between the core and the mantle) surfaces was square-law function from coordinates. Using the new rigorous method we found that the thickness of an ice shell is equal to h ≈ 30 km, and its mass makes only 6.6 % from mass of a stone core. In absence of coherence between two surfaces of level, there is a growth of stresses and restructuring the core and the shell. It is found that the difference between angular velocities on both surfaces doesn't exceed 6 %, which activates a special mechanism of relaxation. The relaxation may lead to considerable (up to 10 %) lengthening the equatorial size of the body. This restructuring the shell leads to accumulation of icy masses at the sharp ends of the planet, which then separate from Haumea. For formation of two satellites of the planet Haumea it has been spent only 8 % from the mass of a shell. Before separation of satellites the planet Haumea was in near-equilibrium state, and its angular momentum was at 1.13 more, and the period of rotation was 16m shorter and made T ≈ 3.64 h. The mechanism predicts that the orbits of satellites can not deviate much from the equatorial plane of Haumea. This is consistent with observations: indeed, the orbit of Namaka is almost in the equatorial plane, and the orbit of massive Hi'iaka deviates only on 13°. The new mechanism can be useful also for studying the evolution of other ice-cover planets and satellites.

  3. Trends In Satellite Communication

    Science.gov (United States)

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.

    1988-01-01

    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  4. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  5. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  6. Biological satellite Kosmos-936

    Science.gov (United States)

    Vedeshin, L. A.

    1978-01-01

    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  7. Small Satellite Transporter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective is to determine whether this small satellite transporter is capable of transporting at least four 6U CubeSats is possible for a given set of...

  8. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  9. The Archimedes satellite system

    Science.gov (United States)

    Taylor, Stuart C.; Shurvinton, William D.

    1992-03-01

    Archimedes is a satellite system conceived by the European Space Agency (ESA) to effectively serve the European market for Mobile Radio Services (MRS). This paper describes the requirements and technical design of the Archimedes satellite system. The underlying assumptions and trade-offs behind the design are detailed and the design is compared and contrasted against alternative design solutions, both technically and economically. A path forward for the development of the system is indicated.

  10. ASTRID II satellit projekt

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Primdahl, Fritz

    1997-01-01

    The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan.......The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan....

  11. Satellite formation. II

    Science.gov (United States)

    Harris, A. W.

    1978-01-01

    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  12. CHINA LAUNCHES NEW SCIENTIFIC SATELLITE

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China on Sept. 27, 2004 launched a scientific satellite atop a Long March 2D carrier rocket from Jiuquan Satellite Launch Center in Gansu province. 10 minutes after the launch, the satellite entered a preset orbit and is running sound at the orbit. It is the 20th recoverable satellite for scientific and technological

  13. Mass balances and dynamic changes of the Bering, Malaspina, and Icy Bay glacier systems of Alaska, United States, and Yukon, Canada

    Science.gov (United States)

    Muskett, Reginald R.

    The Bering and the Malaspina Glacier systems of south-central Alaska, U.S.A., and southwest Yukon Territory, Canada, in the Saint Elias Mountains constitute the two largest temperate surge-type piedmont glaciers on Earth. This is largest region of glaciers and icefields in continental North America. Determining and understanding the causes of wastage of these two glaciers is important to understanding the linkages of glacier mass balance to climate change, glacier dynamics, and the contributions of the glaciers of northwestern North America to rising sea level. Presented are the first detailed estimate of the net mass balances of the Bering and Malaspina Glacier systems, the effects of glacier dynamics on their accumulation areas, and the wastage of the tidewater glaciers of Icy Bay. The combined wastage of the Bering and Malaspina Glacier systems from 1972 to 2003, 254 +/- 16 km 3 water equivalent over a glacier area of 7734 km2, is equivalent to an area-average mass balance of -1.06 +/- 0.07 m/y over that time period. This represents a contribution to global sea-level rise of 0.70 +/- 0.05 mm, 0.023 +/- 0.002 mm/yr from 1972 to 2003. This is roughly 0.8% of the modern sea-level rise as estimated from tide-gauges and satellites, and roughly 9% of the contribution from non-polar glaciers and ice caps. Glacier wastage has been caused by climate warming (negative mass balance) superimposed on the effects of glacier dynamics. Near-concurrent surge of the three largest glaciers of the Malaspina Glacier piedmont were observed during 1999 to 2002. In addition, the tidewater Tyndall Glacier, whose retreat since 1910 was interrupted in 1964 by a major surge, also surged during 1999 to 2002. These four surges have occurred roughly 23 years after the 1976/77 shift of the Pacific Decadal Oscillation to its current warm-wet phase. Despite the increase of high-elevation snow accumulation observed on Mt. Logan, the accumulation areas of the Bering and Malaspina Glacier systems

  14. Post-main Sequence Evolution of Icy Minor Planets: Implications for Water Retention and White Dwarf Pollution

    Science.gov (United States)

    Malamud, Uri; Perets, Hagai B.

    2016-12-01

    Most observations of polluted white dwarf atmospheres are consistent with accretion of water-depleted planetary material. Among tens of known cases, merely two involve accretion of objects that contain a considerable mass fraction of water. The purpose of this study is to investigate the relative scarcity of these detections. Based on a new and highly detailed model, we evaluate the retention of water inside icy minor planets during the high-luminosity stellar evolution that follows the main sequence. Our model fully considers the thermal, physical, and chemical evolution of icy bodies, following their internal differentiation as well as water depletion, from the moment of their birth and through all stellar evolution phases preceding the formation of the white dwarf. We also account for different initial compositions and formation times. Our results differ from previous studies, which have either underestimated or overestimated water retention. We show that water can survive in a variety of circumstances and in great quantities, and therefore other possibilities are discussed in order to explain the infrequency of water detection. We predict that the sequence of accretion is such that water accretes earlier, and more rapidly, than the rest of the silicate disk, considerably reducing the chance of its detection in H-dominated atmospheres. In He-dominated atmospheres, the scarcity of water detections could be observationally biased. It implies that the accreted material is typically intrinsically dry, which may be the result of the inside-out depopulation sequence of minor planets.

  15. 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.

  16. Update on the Intercontinental Cooperative ITP Study Group (ICIS) and on the Pediatric and Adult Registry on Chronic ITP (PARC ITP).

    Science.gov (United States)

    Kühne, Thomas

    2013-01-01

    The Intercontinental Cooperative ITP Study Group (ICIS) was founded in 1997, when the American practice guidelines demonstrated that there is a substantial lack of clinical data. The aim of the group was to promote basic science and clinical research in the field of ITP. Clinical data and more recently DNA is collected to investigate children and adults with ITP. ICIS organizes regular meetings and opened several registries, the most recent being the Pediatric and Adult Registry on Chronic ITP (PARC-ITP), all of which will be briefly discussed. There are many unanswered questions in basic science and clinical research in ITP which need large collaborative studies. The international network of ICIS may be of value in better understanding ITP.

  17. Geophysical Investigation of Subsurface Characteristics of Icy Debris Fans with Ground Penetrating Radar in the Wrangell Mountains, Alaska

    Science.gov (United States)

    Smith, T. D.; Jacob, R. W.

    2013-12-01

    Authors Tracey Smith^1, Rob Jacob^1, Jeffrey Trop^1, Keith Williams^2 and Craig Kochel^1 Bucknell University, Geology and Environmental Geoscience Department, Lewisburg, PA UNAVCO, 6350 Nautilus Dr., Boulder, CO 80301 Icy debris fans have recently been described as deglaciation features on Earth and similar features have been observed on Mars, however, the subsurface characteristics remain unknown. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans near McCarthy, Alaska, USA. The three fans investigated in Alaska are the East, West, and Middle fans which are between the Nabesna ice cap and the McCarthy Glacier. Icy debris fans in general are a largely unexplored suite of paraglacial landforms and processes in alpine regions. Recent field studies focused on direct observations and depositional processes. The results showed that each fan's composition is primarily influenced by the type and frequency of mass wasting processes that supply the fan. Photographic studies show that the East fan receives far more ice and snow avalanches whereas the Middle and West fan receive fewer mass wasting events but more clastic debris is deposited on the Middle and West fan from rock falls and icy debris flows. GPR profiles and WARR surveys consisting of both, common mid-point (CMP), and common shot-point (CSP) surveys investigated the subsurface geometry of the fans and the McCarthy Glacier.All GPR surveys were collected in 2013 with 100MHz bi-static antennas. Four axial profiles and three cross-fan profiles were done on the West and Middle fans as well as the McCarthy Glacier in order to investigate the relationship between the three features. Terrestrial laser surveying of the surface and real-time kinematic GPS provided the surface elevation used to correct the GPR data for topographic changes. GPR profiles yielded reflectors that were continuous for 10+ m and hyperbolic reflections in the subsurface. The WARR

  18. Satellite Communications for ATM

    Science.gov (United States)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  19. Exploring Jupiter's icy moons with old techniques and big facilities - new insights on sulfuric acid hydrates

    Science.gov (United States)

    Maynard-Casely, H. E.; Avdeev, M.; Brand, H.; Wallwork, K.

    2013-12-01

    Sulfuric acid hydrates have been proposed to be abundant on the surface of Europa [1], and hence would be important planetary forming materials for this moon and its companions Ganymede and Callisto. Understanding of the surface features and subsurface of these moons could be advanced by firmer knowledge of the icy materials that comprise them [2], insight into which can be drawn from firmer knowledge of physical properties and phase behaviour of the candidate materials. We wish to present results from a study that started with the question ';What form of sulfuric acid hydrate would form on the surface of Europa'. The intrinsic hydrogen-domination of planetary ices, makes studying these materials with laboratory powder diffraction very challenging. Insights into their crystalline phase behavior and the extraction of a number of thermal and mechanical properties is often only accessible with high-flux synchrotron x-ray diffraction and utilization of the large scattering cross section with neutron diffraction. We have used the Powder Diffraction beamline at Australian synchrotron [4] and the Echidna (High-resolution neutron powder diffraction) instrument of the Australian Nuclear Science and Technology Organization, [5] to obtain an number of new insights into the crystalline phases formed from sulfruic acid and water mixtures. These instruments have enabled the discovery a new water-rich sulfuric acid hydrate form [6], improved structural characterisation of existing forms [7] and a charting the phase diagram of this fundamental binary system [8]. This has revealed exciting potential for understanding more about the surface of Europa from space, perhaps even providing a window into its past. [1] Carlson, R.W., R.E. Johnson, and M.S. Anderson, Science, 1999. 286(5437): p. 97-99. [2] Fortes, A.D. and M. Choukroun. Space Sci Rev, 2010. 153(1-4): p. 185-218. [3] Blake, D., et al., Space Sci Rev,, 2012. 170(1-4): p. 341-399. [4] Wallwork, K.S., Kennedy B. J. and Wang, D

  20. Experimental Satellite 2 Successfully Launched

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Small satellite Experimental Satellite 2 (SY-2) was launched by LM-2C launch vehicle from Xichang Satellite Launch Center on Nov. 18, 2004. Later the satellite entered the preset sun-synchronous orbit, which is 700 kilometers above the earth. The launch was the eighthmission this year by China Aerospace Science and Technology Corporation(CASC), which aims to test the technology of the satellite, conduct survey and monitoring of the land and resources and geographical environment on a trial basis.

  1. China's Meteorological Satellite Application System

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiashen

    2008-01-01

    @@ China's meteorological satellite program consists of five systems,namely the satellite system,the launch vehicle system,the launch center system,TT&C and the ground application system.The satellite system consists of FengYun (FY) polar orbiting series and FY geostationary series,which are launched by LM launch vehicles from Taiyan Satellite Launch Center (TSLC) and Xichang Satellite Launch Center (XSLC) respectively.

  2. Reduction of post injury neointima formation due to 17β-estradiol and phytoestrogen treatment is not influenced by the pure synthetic estrogen receptor antagonist ICI 182,780 in vitro

    Directory of Open Access Journals (Sweden)

    Schochat Thomas

    2002-08-01

    Full Text Available Abstract Background Animal and organ culture experiments have shown beneficial inhibitory estrogen effects on post injury neointima development. The purpose of this study was to investigate whether such estrogen effects are influenced by the estrogen receptor antagonist ICI 182,780. Different concentrations of 17β-estradiol and the phytoestrogens genistein and daidzein were tested. Methods F emale New Zealand White rabbits were benumbed. In situ vascular injury of the thoracic and abdominal aorta was performed by a 3F Fogarty catheter. Segments of 5 mm were randomised and held in culture for 21 days. Three test series were performed: 1 control group – 20 μM ICI – 30 μM ICI – 40 μM ICI. 2 control group – 20 μM ICI – 40 μM 17β-estradiol – 40 μM 17β-estradiol + 20 μM ICI. 3 control group – 20 μM ICI – 40 μM daidzein – 40 μM daidzein + 20 μM ICI – 20 μM genistein – 20 μM genistein + 20 μM ICI. After 21 days the neointima-media-ratio was evaluated. Results 1 Treatment with ICI 182,780 did not reduce neointima formation significantly (p = 0.05. 2 40 μM 17β-estradiol alone (p Conclusions The estrogen receptor antagonist ICI 182,780 did not modulate the inhibitory estrogen effects on post injury neointima formation. These results do not support the idea that such effects are mediated by vascular estrogen receptors.

  3. El surgimiento de la dinámica galileana: historia e historiografía The rising of galilean mechanics: history and historiography

    Directory of Open Access Journals (Sweden)

    Fernando Tula Molina

    2005-09-01

    Full Text Available En el presente trabajo pretendo identificar los puntos de unión críticos, en tanto pasos creativos, que sirvieron a la nueva sintesis en la que Galileo basó su nueva dinámica. En este sentido aspiro a cumplir con el desafío propuesto por Cohen al observar que "el problema no es explicar cómo llegó a utilizar el le-gado griego, a pesar de todo lo interesante que esto pueda tener en sí mismo, sino cómo fue posible trascenderlo". Pretendo mostrar cómo Galileo elabora una nueva síntensis dinámica a partir de cuatro tradiciones diferentes: los lugares naturales de la física aristotélica, el concepto de peso específico de la estática de Arquímedes, el concepto de virtus motiva de Ibn Bayya (Avempace y el concepto de velocidad virtual de la tradición del corpus de ponderibus asociada a Jordano Nemorario. Con base en ese análisis elaboraré un argumento general sobre el alcance limitado de las explicaciones sociológicas en la historia de la ciencia.I'll try to identify the basis of the new Galilean dynamics in few critical and creative turning points. This way I pretend to undertake the challenge posit by H. F. Cohen remarking that "the problem is not to explain the way in which Galileo became aware of Greek legacy, but to explain the way he managed to transcend this legacy". The main points here considered are: the idea of natural places of Aristotle's physics, the concept of specific weight of Archimedes' static, Avempace's concept of virtus motiva and Nemorarius' notion of virtual velocity. In basis of this analysis I'll propose a general argument on the limited scope of sociological explanations in history of science.

  4. Theoretical predictions of source rates for exospheric CO 2 on icy satellites of the outer planets due to sublimation of deep subsurface CO 2 ice

    Science.gov (United States)

    Wood, Stephen E.

    2016-10-01

    The abundances of CO2 observed in the exospheres of Callisto and, more recently, Rhea and Dione are difficult to explain. The previously proposed sources for the CO2 either have production rates well below the expected rates of escape/destruction or should produce other species (e.g. CO) that are not observed.We consider a potential source that has not been previously investigated - CO2 vapor originating from crustal CO2 ice and driven upward by the endogenic heat flux - and have developed a model to make quantitative estimates of the corresponding global subsurface vapor flux.Our model is based on previous theoretical work by Clifford (1993) and Mellon et al. (1997) for equatorial ground ice on Mars, who showed that in times or places where subsurface pore ice is undergoing long-term sublimation and diffusive loss, the ice table (the shallowest depth where any pore ice exists) will not continue to recede indefinitely. Beyond a certain, predictable depth, the linear diffusive profile of vapor density between the ice table and the surface will become supersaturated with respect to the local temperature and recondense as pore ice. This is true for any planetary body with a non-negligible interior heat source (e.g. radiogenic, tidal, etc) and is due to the fact that, while the ice temperature increases ~linearly with depth, the corresponding equilibrium vapor density increases exponentially.Once this occurs, a steady-state profile of ice volume fraction, f_ice(z), develops, with net mass loss only occurring from the retreating pore-filling ice layer. The rate of vapor flux to the surface is then determined only by the vapor density and temperature gradient at the ice table depth. We use a 1-D thermal model coupled with an analytic physical model for regolith thermal conductivity (including its depth- and T-dependence), to calculate the zonally-integrated global CO2 vapor flux corresponding to the range of expected heat flow values. Our preliminary results show agreement with previous estimates of the source flux required to maintain the observed exospheric abundances of CO2 on Callisto, Rhea, and Dione.

  5. Effect of ThermaCare HeatWraps and Icy Hot Cream/Patches on Skin and Quadriceps Muscle Temperature and Blood Flow.

    Science.gov (United States)

    Petrofsky, Jerrold Scott; Laymon, Michael; Berk, Lee; Bains, Gurinder

    2016-03-01

    The purpose of this study was to compare the effects of over-the-counter treatments-ThermaCare HeatWraps (chemical reaction to produce heat above the skin), Icy Hot Patch, and Icy Hot Cream (topically applied menthol)-on skin and deep tissue temperature. This was a longitudinal crossover study. On each of 3 days, a ThermaCare HeatWrap, Icy Hot Cream, or Icy Hot Patch was applied randomly over the quadriceps muscle in 15 healthy volunteers with normal body mass. Skin and muscle temperature and blood flow were measured by laser flowmetry every 15 minutes for 2 hours. After 2 hours, mean temperature decreased by 2.1°C (7.0%; P = .02) in skin and 1.0°C (2.9%; P = .01) in muscle with Icy Hot Cream. Icy Hot Patch decreased skin and muscle temperature by 1.7°C (5.4%; P = .03) and 1.3°C (3.8%; P = .01), respectively. In contrast, ThermaCare raised skin and muscle temperature by 7.8°C (25.8%; P = .001) and 2.7°C (7.7%; P = .002), respectively; both were significantly warmer with ThermaCare vs either Icy Hot product (all P Cream: 56.7 flux [39.3%; P = .003]; Patch: 19.1 flux [16.7%; P = .045]). Muscle blood flow decreased with the Patch (6.7 flux [7.0%; P = .02]). After a period of fluctuations, Icy Hot Cream produced a net increase vs baseline of 7.0 flux (16.9%; P = .02). ThermaCare more than doubled blood flow in skin (83.3 flux [109.7%; P = .0003]) and muscle (25.1 flux [148.5%; P = .004]). In this group of 15 healthy volunteers, ThermaCare HeatWraps provided the greatest degree of tissue warming and increase in tissue blood flow.

  6. Habitability potential of satellites around Jupiter and Saturn

    Science.gov (United States)

    Coustenis, Athena; Raulin, Francois; Encrenaz, Therese; Grasset, Olivier; Solomonidou, Anezina

    2016-07-01

    In looking for habitable conditions in the outer solar system recent research focuses on the natural satellites rather than the planets themselves. Indeed, the habitable zone as traditionally defined may be larger than originally conceived. The outer solar system satellites provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the ground but also by the Voyager, Galileo and the Cassini spacecrafts revealed the potential of these satellites in this context, and our understanding of habitability in the solar system and beyond can be greatly enhanced by investigating several of these bodies together [1]. Their environments seem to satisfy many of the "classical" criteria for habitability (liquid water, energy sources to sustain metabolism and chemical compounds that can be used as nutrients over a period of time long enough to allow the development of life). Indeed, several of the moons show promising conditions for habitability and the development and/or maintenance of life. The strong gravitational pull caused by the giant planets may produce enough energy to sufficiently heat the cores of orbiting icy moons. Europa and Ganymede may be hiding, under their icy crust, putative undersurface liquid water oceans [2] which, in the case of Europa [3], may be in direct contact with a silicate mantle floor and kept warm by tidally generated heat [4]. Titan and Enceladus, Saturn's satellites, were found by the Cassini-Huygens mission to possess active organic chemistries with seasonal variations, unique geological features and possibly internal liquid water oceans. Titan's rigid crust and the probable existence of a subsurface ocean create an analogy with terrestrial-type plate tectonics, at least surficial [5], while Enceladus' plumes find an analogue in geysers. As revealed by Cassini the liquid hydrocarbon lakes [6] distributed mainly at polar latitudes on Titan are ideal isolated environments to look for

  7. Height Matters: Citizen Science with the ICESat-2 Satellite

    Science.gov (United States)

    Casasanto, V.; Campbell, B.; Neumann, T.; Brunt, K. M.

    2016-12-01

    The Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) to be launched in late 2017, will measure the height of Earth from space using lasers, collecting the most precise and detailed account yet of our planet's elevation. The mission will allow scientists to investigate how global warming is changing the planet's icy polar regions and to take stock of Earth's vegetation. ICESat-2's emphasis on polar ice, as well as its unique measurement approach, will provide an intriguing and accessible focus for the mission's education and outreach programs. Sea ice and land ice are areas that have experienced significant change in recent years. It is key to communicate why we are measuring these areas and their importance. ICESat-2 science data will provide much-needed answers to climate change questions such as, "Is the ice really melting in the polar regions?" and "What does studying Earth's frozen regions tell us about our changing climate?" Since the ICESat-2 satellite will be measuring the height of our planet, vegetation and tree height are also of vital interest. With this data, we can see small to large scale changes in Earth's environment. The ICESat-2 Mission is partnering with The GLOBE Program to emphasize these measurements in a hands-on way. Through modified protocols utilizing a hand-held clinometer and GPS, students and citizen scientists in both urban and non-urban areas will be able to measure the heights of trees and buildings to assist NASA in validating the ICESat-2 satellite data.

  8. Solar Power Satellites

    CERN Document Server

    Flournoy, Don M

    2012-01-01

    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  9. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  10. ESA's satellite communications programme

    Science.gov (United States)

    Bartholome, P.

    1985-02-01

    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  11. AVS on satellite

    Science.gov (United States)

    Zhao, Haiwu; Wang, Guozhong; Hou, Gang

    2005-07-01

    AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

  12. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  13. Aqueous geochemistry in icy world interiors: Equilibrium fluid, rock, and gas compositions, and fate of antifreezes and radionuclides

    Science.gov (United States)

    Neveu, Marc; Desch, Steven J.; Castillo-Rogez, Julie C.

    2017-09-01

    The geophysical evolution of many icy moons and dwarf planets seems to have provided opportunities for interaction between liquid water and rock (silicate and organic solids). Here, we explore two ways by which water-rock interaction can feed back on geophysical evolution: the production or consumption of antifreeze compounds, which affect the persistence and abundance of cold liquid; and the potential leaching into the fluid of lithophile radionuclides, affecting the distribution of a long-term heat source. We compile, validate, and use a numerical model, implemented with the PHREEQC code, of the interaction of chondritic rock with pure water and with C, N, S-bearing cometary fluid, thought to be the materials initially accreted by icy worlds, and describe the resulting equilibrium fluid and rock assemblages at temperatures, pressures, and water-to-rock ratios of 0-200 ° C, 1-1000 bar, and 0.1-10 by mass, respectively. Our findings suggest that water-rock interaction can strongly alter the nature and amount of antifreezes, resulting in solutions rich in reduced nitrogen and carbon, and sometimes dissolved H2, with additional sodium, calcium, chlorine, and/or oxidized carbon. Such fluids can remain partially liquid down to 176 K if NH3 is present. The prominence of Cl in solution seems to hinge on its primordial supply in ices, which is unconstrained by the meteoritical record. Equilibrium assemblages, rich in serpentine and saponite clays, retain thorium and uranium radionuclides unless U-Cl or U-HCO3 complexing, which was not modeled, significantly enhances U solubility. However, the radionuclide 40 K can be leached at high water:rock ratio and/or low temperature at which K is exchanged with ammonium in minerals. We recommend the inclusion of these effects in future models of the geophysical evolution of ocean-bearing icy worlds. Our simulation products match observations of chloride salts on Europa and Enceladus; CI chondrites mineralogies; the observation of

  14. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  15. Declassified intelligence satellite photographs

    Science.gov (United States)

    ,

    1998-01-01

    Recently declassified photographs from spy satellites are an important addition to the record of the Earth?s land surface held by the U.S. Geological Survey (USGS). More than 800,000 high-resolution photos taken between 1959 through 1972 were made available by Executive Order of the President. The collection is held at the USGS EROS Data Center, near Sioux Falls, S. Dak., and are offered for public sale. For some purposes in earth science studies, these photos extend the record of changes in the land surface another decade back in time from the advent of the Landsat earth-observing satellite program.

  16. Oceanography from satellites

    Science.gov (United States)

    Wilson, W. S.

    1981-01-01

    It is pointed out that oceanographers have benefited from the space program mainly through the increased efficiency it has brought to ship operations. For example, the Transit navigation system has enabled oceanographers to compile detailed maps of sea-floor properties and to more accurately locate moored subsurface instrumentation. General descriptions are given of instruments used in satellite observations (altimeter, color scanner, infrared radiometer, microwave radiometer, scatterometer, synthetic aperture radar). It is pointed out that because of the large volume of data that satellite instruments generate, the development of algorithms for converting the data into a form expressed in geophysical units has become especially important.

  17. Satellite oceanography - The instruments

    Science.gov (United States)

    Stewart, R. H.

    1981-01-01

    It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

  18. Integrated Satellite-HAP Systems

    DEFF Research Database (Denmark)

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo

    2005-01-01

    for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite- based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used......Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element...

  19. The inner small satellites of Saturn: Their varied surfaces tell dynamic tales

    Science.gov (United States)

    Thomas, Peter C.; Helfenstein, P.; Burns, J. A.

    2013-10-01

    According to images from the Cassini Imaging Science Subsystem (ISS), the surface forms and overall shapes of Saturn’s inner small satellites occur in groups that populate different orbital niches. Co-orbitals Janus and Epimetheus are the most lunar-like of the small satellites; ring moons Atlas, Pan, and Daphnis have latitude-dependent morphology likely related to how ring material is supplied (Charnoz et al., 2007). The shepherding moon Prometheus may show a stripped mantle/core structure. Arc/ring embedded moons are small, smooth ellipsoids, unique among well-imaged small solar system objects. The Trojan satellites (Calypso, Telesto, Helene) have deep coverings showing multi-step histories of deposition and erosion, and include branching networks of downslope transport. We report the quantitative characteristics of these bodies’ shapes, mean properties, and surface characteristics. The differences may arise from the amounts of loose material available to cover the surfaces. Modeling of ejecta sources from large icy satellites in addition to interactions with ring particles may be required to explain all the variation among these small, icy bodies. The semi-global drainage patterns on the Trojans are especially enigmatic. Why is there nothing comparable on other small satellites? The tapered albedo markings on the Trojans suggest process-specific surface properties. Cassini ISS UV3/IR3 color ratios show that, for Helene, erosion and downslope motion result in a surface that is bluer in color; or a less active surface remains/becomes redder. Sustained exogenic processes such as E-ring particle impacts and charged-particle bombardment compete with geological processes, but on the Trojans, both leave strong signatures. The different amounts of interconnected surfaces on the small satellites range from the cratered landscapes of Janus and Epimetheus, through the semi-global drainage patterns of the Trojans, to complete smoothing of the arc/ring embedded objects

  20. Immediate haemodynamic effects of a novel partial agonist, beta 1-adrenoceptor blocking drug ICI 141,292 after intravenous administration to healthy young volunteers and patients with ischaemic heart disease

    DEFF Research Database (Denmark)

    Bonde, J; Svendsen, T L; Lyngborg, K;

    1987-01-01

    ICI 141,292 is a new beta 1-adrenoceptor blocking drug. The beta 1-adrenoceptor antagonistic effect of ICI 141,292 was examined in a double-blind, randomised crossover study in eight healthy young volunteers and compared with atenolol. Three doses of ICI 141,292 (1, 2 and 4 mg) and atenolol 5 mg...... were administered intravenously. The attenuation in exercise induced tachycardia varied between 16.0 and 21.2% (P less than 0.01). A significant reduction in blood pressure could be demonstrated following all three doses of ICI 141,292 and atenolol during exercise. At rest in the sitting position HR...... decreased approximately 8% following all three doses of ICI 141,292 and 14.9% after atenolol 5 mg. No changes in blood pressure were observed under resting conditions after any of the drugs. In six patients with ischaemic heart disease the intrinsic sympathomimetic activity following intravenous...

  1. Proving the Orbits of the Galilean Moons Through Astrophotography. (Spanish Title: Comprobando Las Órbitas de Las Lunas Galileanas a Través de la Astrofotografía.) Evidenciando as Órbitas das Luas Galileanas Atravéd da Astrofotografia

    Science.gov (United States)

    Iachel, Gustavo

    2009-12-01

    An activity related to the observation of the Galilean moons and to amateur astrophotography is presented in this work. Through the reading of excerpts of the book Sidereus Nuncius (Sidereal Messenger), by Galileo, it is possible to trace a methodology to observe the planet and its natural satellites and, with the aid of the astrophotography, to analyze the field recordings. Moreover, it is possible to compare the images obtained after plotting the relative positions of these moons to prove their orbits. This activity can be conducted by teachers, students and amateur astronomers, in order to develop their capabilities of observation of astronomical phenomena. Se presenta en este trabajo una actividad relacionada a la observación de las lunas Galileanas y a la astrofotografía amateur. A través de la lectura de tramos de la obra Sidereus Nuncius (El Mensajero Sideral) de Galileo, es posible trazar una metodología para la observación del planeta y de sus satélites naturales y, con el auxilio de la astrofotografía, analizar las anotaciones de campo. Además, es posible comparar las imágenes obtenidas con el gráfico de las posiciones relativas de estas lunas para comprobar sus órbitas. Esa actividad puede ser realizada por maestros, estudiantes y astrónomos amateurs, de forma a desarrollar sus capacidades de observación de los fenómenos astronómicos. Uma atividade relacionada à observação das luas Galileanas e à astrofotografia amadora é apresentada neste trabalho. Através da leitura de trechos da obra Sidereus Nuncius (Mensageiro Sideral), de Galileu, é possível traçar uma metodologia para a observação do planeta e de seus satélites naturais e, com o auxílio da astrofotografia, analisar as anotações de campo. Além disso, é possível comparar as imagens obtidas com o gráfico das posições relativas destas luas para evidenciar suas órbitas. Essa atividade pode ser realizada por professores, estudantes e astrônomos amadores, de forma a

  2. Satellite orbit determination and gravity field recovery from satellite-to-satellite tracking

    Science.gov (United States)

    Wakker, K. F.; Ambrosius, B. A. C.; Leenman, H.

    1989-07-01

    Studies on satellite-to-satellite tracking (SST) with POPSAT (a geodetic satellite concept) and a ERS-class (Earth observation) satellite, a Satellite-to-Satellite Tracking (SST) gravity mission, and precise gravity field determination methods and mission requirements are reported. The first two studies primarily address the application of SST between the high altitude POPSAT and an ERS-class or GRM (Geopotential Research Mission) satellite to the orbit determination of the latter two satellites. Activities focussed on the determination of the tracking coverage of the lower altitude satellite by ground based tracking systems and by POPSAT, orbit determination error analysis and the determination of the surface forces acting on GRM. The third study surveys principles of SST, uncertainties of existing drag models, effects of direct luni-solar attraction and tides on orbit and the gravity gradient observable. Detailed ARISTOTELES (which replaced POPSAT) orbit determination error analyses were performed for various ground based tracking networks.

  3. Rapid Coagulation of Porous Dust Aggregates Outside the Snow Line: A Pathway to Successful Icy Planetesimal Formation

    CERN Document Server

    Okuzumi, Satoshi; Kobayashi, Hiroshi; Wada, Koji

    2012-01-01

    Rapid orbital drift of macroscopic dust particles is one of the major obstacles against planetesimal formation in protoplanetary disks. We reexamine this problem by considering porosity evolution of dust aggregates. We apply a porosity model based on recent N-body simulations of aggregate collisions, which allows us to study the porosity change upon collision for a wide range of impact energies. As a first step, we neglect collisional fragmentation and instead focus on dust evolution outside the snow line, where the fragmentation has been suggested to be less significant than inside the snow line because of a high sticking efficiency of icy particles. We show that dust particles can evolve into highly porous aggregates (with internal densities of much less than 0.1 g/cm^3) even if collisional compression is taken into account. We also show that the high porosity triggers significant acceleration in collisional growth. This acceleration is a natural consequence of particles' aerodynamical property at low Knuds...

  4. Manchester Ice Nucleus Counter (MINC measurements from the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007

    Directory of Open Access Journals (Sweden)

    H. M. Jones

    2010-08-01

    Full Text Available An ice nucleus counter was developed and constructed to enable investigation of potential ice nucleating materials. The Manchester Ice Nucleus Chamber (MINC is a concentric-cylinder continuous flow diffusion chamber (CFDC. A full explanation of the MINC instrument is given here, along with first results and a comparison to an established instrument of similar design (Colorado State University CFDC during sampling of common ice nucleating aerosols at the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007. Both instruments detected the onset of ice nucleation under similar conditions of temperature and supersaturation for several different types of ice nuclei. Comparisons of the ratio of ice nuclei to total aerosol concentrations as a function of relative humidity (RH showed agreement within one order of magnitude. Possible reasons for differences between the two instruments relating to differences in their design are discussed, along with suggestions to future improvements to the current design.

  5. Manchester Ice Nucleus Counter (MINC) measurements from the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007)

    Science.gov (United States)

    Jones, H. M.; Flynn, M. J.; Demott, P. J.; Möhler, O.

    2011-01-01

    An ice nucleus counter was developed and constructed to enable investigation of potential ice nucleating materials. The Manchester Ice Nucleus Chamber (MINC) is a concentric-cylinder continuous flow diffusion chamber (CFDC). A full explanation of the MINC instrument is given here, along with first results and a comparison to an established instrument of similar design (Colorado State University CFDC) during sampling of common ice nucleating aerosols at the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007). MINC and CSU-CFDC detected the onset of ice nucleation under similar conditions of temperature and supersaturation for several different types of ice nuclei. Comparisons of the ratio of ice nuclei to total aerosol concentrations as a function of supersaturation with respect to water (SSw) showed agreement within one order of magnitude. Possible reasons for differences between the two instruments relating to differences in their design are discussed, along with suggestions to future improvements to the current design.

  6. Detrusor underactivity and the underactive bladder: Symptoms, function, cause-what do we mean? ICI-RS think tank 2014.

    Science.gov (United States)

    Smith, Phillip P; Birder, Lori A; Abrams, Paul; Wein, Alan J; Chapple, Chris R

    2016-02-01

    Impaired bladder emptying is a well-recognized cause of lower urinary tract symptoms. However, the symptoms produced do not always relate to voiding, and may include frequency, urgency and incontinence. Conversely, the etiology of symptoms of disturbed voiding is not necessarily dependent upon objectively impaired voiding. Terms including underactive bladder, detrusor underactivity, and impaired contractility describe aspects of these problems, and have been used somewhat interchangeably. It is possible that the present lack of effective therapy in many cases relates to both etiologic and diagnostic uncertainty stemming from terminologic imprecision. Detrusor underactivity has a standardized definition, unlike underactive bladder and impaired contractility. The relationships of symptoms, function, and cause were the focus of a 2014 ICI-RS Think Tank entitled Does Detrusor Underactivity Exist, and if so it is neurogenic, myogenic, or both? This review presents a summary of the problem and the Think Tank conclusions. A terminologic hierarchy and specific research goals are presented.

  7. Targeting the American market for medicines, ca. 1950s-1970s: ICI and Rhône-Poulenc compared.

    Science.gov (United States)

    Quirke, Viviane

    2014-01-01

    The forces that have shaped American medicine include a wide set of interrelated changes, among them the changing research, development, and marketing practices of the pharmaceutical industry. This article compares the research and development (R&D) and marketing strategies of the British group Imperial Chemical Industries (ICI, whose Pharmaceutical Division was spun off and merged with the Swedish company Astra to form AstraZeneca) and its French counterpart Rhône-Poulenc (now part of Sanofi-Aventis) in dealing with the American medical market. It examines how, in the process, the relationship between R&D and marketing was altered, and the firms themselves were transformed. The article also questions the extent to which their approaches to this market, one of the most significant markets for drugs in general, and for anticancer drugs in particular, became standardized in the period of "scientific marketing."

  8. Estrogen and pure antiestrogen fulvestrant (ICI 182 780) augment cell–matrigel adhesion of MCF-7 breast cancer cells through a novel G protein coupled estrogen receptor (GPR30)-to-calpain signaling axis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan; Li, Zheng; He, Yan; Shang, Dandan; Pan, Jigang; Wang, Hongmei; Chen, Huamei; Zhu, Zhuxia [Department of Physiology/Cancer Research Group, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China); Wan, Lei [Department of Pharmacology, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China); Wang, Xudong, E-mail: xdwang@gmc.edu.cn [Department of Physiology/Cancer Research Group, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China)

    2014-03-01

    Fulvestrant (ICI 182 780, ICI) has been used in treating patients with hormone-sensitive breast cancer, yet initial or acquired resistance to endocrine therapies frequently arises and, in particular, cancer recurs as metastasis. We demonstrate here that both 17-beta-estradiol (E2) and ICI enhance cell adhesion to matrigel in MCF-7 breast cancer cells, with increased autolysis of calpain 1 (large subunit) and proteolysis of focal adhesion kinase (FAK), indicating calpain activation. Additionally, either E2 or ICI induced down-regulation of estrogen receptor α without affecting G protein coupled estrogen receptor 30 (GPR30) expression. Interestingly, GPR30 agonist G1 triggered calpain 1 autolysis but not calpain 2, whereas ER agonist diethylstilbestrol caused no apparent calpain autolysis. Furthermore, the actions of E2 and ICI on calpain and cell adhesion were tremendously suppressed by G15, or knockdown of GPR30. E2 and ICI also induced phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2), and suppression of ERK1/2 phosphorylation by U0126 profoundly impeded calpain activation triggered by estrogenic and antiestrogenic stimulations indicating implication of ERK1/2 in the GPR30-mediated action. Lastly, the E2- or ICI-induced cell adhesion was dramatically impaired by calpain-specific inhibitors, ALLN or calpeptin, suggesting requirement of calpain in the GPR30-associated action. These data show that enhanced cell adhesion by E2 and ICI occurs via a novel GPR30-ERK1/2-calpain pathway. Our results indicate that targeting the GPR30 signaling may be a potential strategy to reduce metastasis and improve the efficacy of antiestrogens in treatment of advanced breast cancer. - Highlights: • Estrogen and ICI augment adhesion to matrigel with calpain activation in MCF-7 cells. • GPR30 mediates cell–matrigel adhesion and calpain activation via ERK1/2. • Calpain is required in the cell–matrigel adhesion induced by E2 and ICI.

  9. Gasoline from coal in the state of Illinois: feasibility study. Volume I. Design. [KBW gasification process, ICI low-pressure methanol process and Mobil M-gasoline process

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Volume 1 describes the proposed plant: KBW gasification process, ICI low-pressure methanol process and Mobil M-gasoline process, and also with ancillary processes, such as oxygen plant, shift process, RECTISOL purification process, sulfur recovery equipment and pollution control equipment. Numerous engineering diagrams are included. (LTN)

  10. Gasoline from coal in the state of Illinois: feasibility study. Volume I. Design. [KBW gasification process, ICI low-pressure methanol process and Mobil M-gasoline process

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Volume 1 describes the proposed plant: KBW gasification process, ICI low-pressure methanol process and Mobil M-gasoline process, and also with ancillary processes, such as oxygen plant, shift process, RECTISOL purification process, sulfur recovery equipment and pollution control equipment. Numerous engineering diagrams are included. (LTN)

  11. A putative Type IIS restriction endonuclease GeoICI from Geobacillus sp. – A robust, thermostable alternative to mezophilic prototype BbvI

    Indian Academy of Sciences (India)

    Joanna Zebrowska; Olga Zołnierkiewicz; Marta A Skowron; Agnieszka Zylicz-Stachula; Joanna Jezewska-Frackowiak; Piotr M Skowron

    2016-03-01

    Screening of extreme environments in search for novel microorganisms may lead to the discovery of robust enzymes with either new substrate specificities or thermostable equivalents of those already found in mesophiles, better suited for biotechnology applications. Isolates from Iceland geysers’ biofilms, exposed to a broad range of temperatures, from ambient to close to water boiling point, were analysed for the presence of DNA-interacting proteins, including restriction endonucleases (REases). GeoICI, a member of atypical Type IIS REases, is the most thermostable isoschizomer of the prototype BbvI, recognizing/cleaving 5′-GCAGC(N8/12)-3′ DNA sequences. As opposed to the unstable prototype, which cleaves DNA at 30°C, GeoICI is highly active at elevated temperatures, up to 73°C and over a very wide salt concentration range. Recognition/cleavage sites were determined by: (i) digestion of plasmid and bacteriophage lambda DNA (λ); (ii) cleavage of custom PCR substrates, (iii) run-off sequencing of GeoICI cleavage products and (iv) shotgun cloning and sequencing of λ DNA fragmented with GeoICI. Geobacillus sp. genomic DNA was PCR-screened for the presence of other specialized REases-MTases and as a result, another putative REase-MTase, GeoICII, related to the Thermus sp. family of bifunctional REases-methyltransferases (MTases) was detected.

  12. A putative Type IIS restriction endonuclease GeoICI from Geobacillus sp.--A robust, thermostable alternative to mezophilic prototype BbvI.

    Science.gov (United States)

    Zebrowska, Joanna; Zolnierkiewicz, Olga; Skowron, Marta A; Zylicz-Stachula, Agnieszka; Jezewska-Frackowiak, Joanna; Skowron, Piotr M

    2016-03-01

    Screening of extreme environments in search for novel microorganisms may lead to the discovery of robust enzymes with either new substrate specificities or thermostable equivalents of those already found in mesophiles, better suited for biotechnology applications. Isolates from Iceland geysers' biofilms, exposed to a broad range of temperatures, from ambient to close to water boiling point, were analysed for the presence of DNA-interacting proteins, including restriction endonucleases (REases). GeoICI, a member of atypical Type IIS REases, is the most thermostable isoschizomer of the prototype BbvI, recognizing/cleaving 5'-GCAGC(N8/12)-3'DNA sequences. As opposed to the unstable prototype, which cleaves DNA at 30°C, GeoICI is highly active at elevated temperatures, up to 73°C and over a very wide salt concentration range. Recognition/cleavage sites were determined by: (i) digestion of plasmid and bacteriophage lambda DNA (Λ); (ii) cleavage of custom PCR substrates, (iii) run-off sequencing of GeoICI cleavage products and (iv) shotgun cloning and sequencing of Λ DNA fragmented with GeoICI. Geobacillus sp. genomic DNA was PCR-screened for the presence of other specialized REases-MTases and as a result, another putative REase- MTase, GeoICII, related to the Thermus sp. family of bifunctional REases-methyltransferases (MTases) was detected.

  13. When should video and EMG be added to urodynamics in children with lower urinary tract dysfunction and is this justified by the evidence? ICI-RS 2014

    NARCIS (Netherlands)

    Anding, Ralf; Smith, Phillip; de Jong, Tom; Constantinou, Christos; Cardozo, Linda; Rosier, Peter

    2016-01-01

    AIMS: An ICI-RS Think Tank in 2014 discussed and evaluated the evidence for adding video and EMG to urodynamics (UDS) in children and also highlighted evidence gaps, with the aim of recommending further clinical and research protocols. METHODS: A systematic analysis of the relevant literature for bo

  14. When should video be added to conventional urodynamics in adults and is it justified by the evidence? ICI-RS 2014

    NARCIS (Netherlands)

    Anding, Ralf; Rosier, Peter; Smith, Phillip; Gammie, Andrew; Giarenis, Ilias; Rantell, Angela; Thiruchelvam, Nikesh; Arlandis, Salvador; Cardozo, Linda

    2016-01-01

    AIMS: To debate and evaluate the evidence base regarding the added value of video to urodynamics in adults and to define research questions. METHODS: In the ICI-RS Meeting 2014 a Think Tank analyzed the current guidelines recommending video urodynamics (VUD) and performed a literature search to dete

  15. Late Noachian Icy Highlands Climate Model: Exploring the Possibility of Transient Melting and Fluvial/Lacustrine Activity Through Peak Annual and Seasonal Temperatures

    Science.gov (United States)

    Palumbo, A. M.; Head, J. W.; Wordsworth, R. D.

    2017-10-01

    We use the LMD GCM to explore the role of seasonal and diurnal temperature variation on a "cold and icy" early Mars. In a cold climate with MAT 243 K, peak summertime conditions permit ice melt, runoff, and possibly valley network formation.

  16. Mineralogy of Rock Flour in Glaciated Volcanic Terrains: An Analog for a Cold and Icy Early Mars

    Science.gov (United States)

    Rampe, E. B.; Horgan, B.; Scudder, N.; Smith, R. J.; Rutledge, A. M.

    2017-01-01

    Geomorphological and mineralogical data from early Martian surfaces indicate liquid water was present on ancient Mars. The relative surface temperatures, however, remain a subject of debate. Was early Mars warm and wet or cold and icy with punctuated periods of warmth and ice melt? By characterizing the mineralogy and geochemistry of modern icy mafic terrains on Earth, we can search for these characteristics in early Martian terrains to better constrain the early Martian climate. Here, we describe the mineralogy of glacial flour in a modern glaciated volcanic terrain in Oregon, USA. We are particularly interested in secondary phases that form in these environments, and we hypothesize that poorly crystalline phases may preferentially form in these terrains because of the low temperatures and the seasonality of melt water production. A description of the mineralogy of the moraines, the composition of the amorphous materials, and the geochemistry of the glacial melt waters are presented elsewhere. Glacial flour is made up of silt- and clay-sized particles that form from the physical weathering of rock underlying a wet-based glacier as the glacier slides over it. Flour is usually transported from underneath a glacier by melt water streams. The geochemistry of glacial melt water streams has been studied extensively and has been used to infer weathering reactions within glacial systems. However, the mineralogy of these environments, especially on mafic volcanic terrains, is not well studied. Rock flour is a ubiquitous physical weathering product in glaciated terrains and, therefore, affects microbial habitats, stream and lake chemistry, and chemical weathering processes. and by studying the mineralogy of glacial flour, we can better understand geochemical and microbiological processes in subglacial and proglacial terrains.

  17. Man-made Satellites

    Institute of Scientific and Technical Information of China (English)

    郝昌明

    2005-01-01

    If you watch the sky about an hour after the sun goes down, you may see some “moving stars”. But they're not real stars. They're manmade satellites (卫星). And the biggest of all is the International Space Station (ISS国际空间站).

  18. Observations of artificial satellites

    Directory of Open Access Journals (Sweden)

    A. MAMMANO

    1964-06-01

    Full Text Available The following publication gives the results of photographic
    observations of artificial satellites made at Asiago during the second
    and third year of this programme. The fixed camera technique and that
    with moving film (the latter still in its experimental stage have been used.

  19. Experimental Satellite Quantum Communications.

    Science.gov (United States)

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  20. Perception via satellite

    Science.gov (United States)

    Robinove, Charles J.

    1970-01-01

    The earth resources observation satellite (EROS) program in the Department of the Interior is intended to gather and use data from satellites and aircraft on natural and man-made features of the earth's surface. Earth resources technology satellite will provide the EROS program with data for use in dealing with natural resource problems and understanding the interaction between man and the environment. Applications will include studies of tectonic features, hydrologic problems, location of fish schools, determination of the conditions of range land, mapping land use for urban planning, studies of erosion and change along coastlines and major streams, and inventories of land use and land forms. In addition, the ERTS data may be used for detecting forest and crop diseases and inventorying crops. The ERTS satellite will be in a polar, sun-synchronous orbit so that each point on the earth's surface will be sensed every 17 to 20 days, at the same time of day. Multispectral photography is being investigated for its usefulness in hydrology. Side-looking airborne radar has not yet been widely used in hydrologic studies, although it is an excellent tool for all-weather, day or night, coverage of large areas. Other techniques being investigated include passive microwave radiometry, ultraviolet and visible stimulated luminescence, and absorption spectroscopy.

  1. Satellite Photometric Error Determination

    Science.gov (United States)

    2015-10-18

    of nearly specular reflections from most solar panels. Our primary purpose in presenting these two plots is to demonstrate the usefulness of...than a transformation for stars because the spectral energy distribution of satellites can change with phase angle and is subject to specular

  2. Creating Better Satellite Conferences.

    Science.gov (United States)

    Horner, Tommy

    1998-01-01

    Presents four ways to improve broadcasts of company satellite conferences, including creative site selection (using facilities at educational institutions rather than hotel rooms); creative programming (using graphics and other interruptions to break up lectures or speeches); creative crew selection; and creative downlink site activities (to…

  3. Ocean surveillance satellites

    Science.gov (United States)

    Laurent, D.

    Soviet and U.S. programs involving satellites for surveillance of ships and submarines are discussed, considering differences in approaches. The Soviet program began with the Cosmos 198 in 1967 and the latest, the Cosmos 1400 series, 15 m long and weighing 5 tons, carry radar for monitoring ships and a nuclear reactor for a power supply. Other Soviet spacecraft carrying passive microwave sensors and ion drives powered by solar panels have recently been detonated in orbit for unknown reasons. It has also been observed that the Soviet satellites are controlled in pairs, with sequential orbital changes for one following the other, and both satellites then overflying the same points. In contrast, U.S. surveillance satellites have been placed in higher orbits, thus placing greater demands on the capabilities of the on-board radar and camera systems. Project White Cloud and the Clipper Bow program are described, noting the continued operation of the White Cloud spacecraft, which are equipped to intercept radio signals from surface ships. Currently, the integrated tactical surveillance system program has completed its study and a decision is expected soon.

  4. OMV With Satellite

    Science.gov (United States)

    1986-01-01

    This 1986 artist's concept shows the Orbital Maneuvering Vehicle (OMV) towing a satellite. As envisioned by Marshall Space Flight Center plarners, the OMV would be a remotely-controlled free-flying space tug which would place, rendezvous, dock, and retrieve orbital payloads.

  5. Advances in satellite oceanography

    Science.gov (United States)

    Brown, O. B.; Cheney, R. E.

    1983-01-01

    Technical advances and recent applications of active and passive satellite remote sensing techniques to the study of oceanic processes are summarized. The general themes include infrared and visible radiometry, active and passive microwave sensors, and buoy location systems. The surface parameters of sea surface temperature, windstream, sea state, altimetry, color, and ice are treated as applicable under each of the general methods.

  6. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  7. What Is Eating Ozone? Thermal Reactions between SO2 and O3: Implications for Icy Environments

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2016-12-01

    Laboratory studies are presented, showing for the first time that thermally driven reactions in solid H2O + SO2 + O3 mixtures can occur below 150 K, with the main sulfur-containing product being bisulfate ({{{HSO}}4}-). Using a technique not previously applied to the low-temperature kinetics of either interstellar or solar-system ice analogs, we estimate an activation energy of 32 kJ mol-1 for {{{HSO}}4}- formation. These results show that at the temperatures of the Jovian satellites, SO2 and O3 will efficiently react making detection of these molecules in the same vicinity unlikely. Our results also explain why O3 has not been detected on Callisto and why the SO2 concentration on Callisto appears to be highest on that world’s leading hemisphere. Furthermore, our results predict that the SO2 concentration on Ganymede will be lowest in the trailing hemisphere, where the concentration of O3 is the highest. Our work suggests that thermal reactions in ices play a much more important role in surface and sub-surface chemistry than generally appreciated, possibly explaining the low abundance of sulfur-containing molecules and the lack of ozone observed in comets and interstellar ices.

  8. Defense Meteorological Satellite Program (DMSP)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Defense Meteorological Satellite Program (DMSP) satellites collect visible and infrared cloud imagery as well as monitoring the atmospheric, oceanographic,...

  9. DFH Satellite Co.,Ltd.

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    DFH Satellite Co.,Ltd. is a hi-tech enterprise founded and sponsored by China Aerospace Science and Technology Corporation(CASC) and one of CASC subsidiaries,China Academy of Space Technology (CAST). The company is mainly engaged in the research and development of small satellites and micro-satellites, Osystem designs and product development for satellite application projects as well as the international exchanges and cooperation.

  10. Short-term effects of β2-AR blocker ICI 118,551 on sarcoplasmic reticulum SERCA2a and cardiac function of rats with heart failure.

    Science.gov (United States)

    Gong, Haibin; Li, Yanfei; Wang, Lei; Lv, Qian; Wang, Xiuli

    2016-09-01

    The study was conducted to examine the effects of ICI 118,551 on the systolic function of cardiac muscle cells of rats in heart failure and determine the molecular mechanism of selective β2-adrenergic receptor (β2-AR) antagonist on these cells. The chronic heart failure model for rats was prepared through abdominal aortic constriction and separate cardiac muscle cells using the collagenase digestion method. The rats were then divided into Sham, HF and HF+ICI 50 nM goups and cultivated for 48 h. β2-AR, Gi/Gs and sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) protein expression levels in the cardiac muscle cells were evaluated by western blotting and changes in the systolic function of cardiac muscle cells based on the boundary detection system of contraction dynamics for individual cells was measured. The results showed that compared with the Sham group, the survival rate, percentage of basic contraction and maximum contraction amplitude percentage of cardiac muscle cells with heart failure decreased, Gi protein expression increased while Gs and SERCA2a protein expression decreased. Compared with the HF group, the maximum contraction amplitude percentage of cardiac muscle cells in group HF+ICI 50 nM decreased, the Gi protein expression level increased while the SERCA2a protein expression level decreased. Following the stimulation of Ca(2+) and ISO, the maximum contraction amplitude percentage of cardiac muscle cells in the HF+ICI 50 nM group was lower than that in group HF. This indicated that ICI 118,551 has negative inotropic effects on cardiac muscle cells with heart failure, which may be related to Gi protein. Systolic function of cardiac muscle cells with heart failure can therefore be reduced by increasing Gi protein expression and lowering SERCA2a protein expression.

  11. The role of ejecta in the small crater populations on the mid-sized saturnian satellites

    Science.gov (United States)

    Bierhaus, Edward B.; Dones, Luke; Alvarellos, José Luis; Zahnle, Kevin

    2012-03-01

    We find evidence, by both observation and analysis, that primary crater ejecta play an important role in the small crater (less than a few km) populations on the saturnian satellites, and more broadly, on cratered surfaces throughout the Solar System. We measure crater populations in Cassini images of Enceladus, Rhea, and Mimas, focusing on image data with scales less than 500 m/pixel. We use recent updates to crater scaling laws and their constants (Housen, K.R., Holsapple, K.A. [2011]. Icarus 211, 856-875) to estimate the amount of mass ejected in three different velocity ranges: (i) greater than escape velocity, (ii) less than escape velocity and faster than the minimum velocity required to make a secondary crater (vmin), and (iii) velocities less than vmin. Although the vast majority of mass on each satellite is ejected at speeds less than vmin, our calculations demonstrate that the differences in mass available in the other two categories should lead to observable differences in the small crater populations; the predictions are borne out by the measurements we have made to date. In particular, Rhea, Tethys, and Dione have sufficient surface gravities to retain ejecta moving fast enough to make secondary crater populations. The smaller satellites, such as Enceladus but especially Mimas, are expected to have little or no traditional secondary populations because their escape velocities are near the threshold velocity necessary to make a secondary crater. Our work clarifies why the Galilean satellites have extensive secondary crater populations relative to the saturnian satellites. The presence, extent, and sizes of sesquinary craters (craters formed by ejecta that escape into temporary orbits around Saturn before re-impacting the surface, see Dobrovolskis, A.R., Lissauer, J.J. [2004]. Icarus 169, 462-473; Alvarellos, J.L., Zahnle, K.J., Dobrovolskis, A.R., Hamill, P. [2005]. Icarus 178, 104-123; Zahnle, K., Alvarellos, J.L., Dobrovolskis, A.R., Hamill, P. [2008

  12. Telelibrary: Library Services via Satellite.

    Science.gov (United States)

    Liu, Rosa

    1979-01-01

    Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

  13. Mobile satellite service for Canada

    Science.gov (United States)

    Sward, David

    1988-05-01

    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  14. Satellite Aerodynamics and Density Determination from Satellite Dynamic Response

    Science.gov (United States)

    Karr, G. R.

    1972-01-01

    The aerodynamic drag and lift properties of a satellite are first expressed as a function of two parameters associated with gas-surface interaction at the satellite surface. The dynamic response of the satellite as it passes through the atmosphere is then expressed as a function of the two gas-surface interaction parameters, the atmospheric density, the satellite velocity, and the satellite orientation to the high speed flow. By proper correlation of the observed dynamic response with the changing angle of attack of the satellite, it is found that the two unknown gas-surface interaction parameters can be determined. Once the gas-surface interaction parameters are known, the aerodynamic properties of the satellite at all angles of attack are also determined.

  15. Proceedings of the International Cancer Imaging Society (ICIS 16th Annual Teaching Course

    Directory of Open Access Journals (Sweden)

    Dow-Mu Koh

    2016-10-01

    Full Text Available Table of contents O1 Tumour heterogeneity: what does it mean? Dow-Mu Koh O2 Skeletal sequelae in adult survivors of childhood cancer Sue Creviston Kaste O3 Locoregional effects of breast cancer treatment Sarah J Vinnicombe O4 Imaging of cancer therapy-induced CNS toxicity Giovanni Morana, Andrea Rossi O5 Screening for lung cancer Christian J. Herold O6Risk stratification of lung nodules Theresa C. McLoud O7 PET imaging of pulmonary nodules Kirk A Frey O8 Transarterial tumour therapy Bernhard Gebauer O9 Interventional radiology in paediatric oncology Derek Roebuck O10 Image guided prostate interventions Jurgen J. Fütterer O11 Imaging cancer predisposition syndromes Alexander J. Towbin O12Chest and chest wall masses Thierry AG Huisman O13 Abdominal masses: good or bad? Anne MJB Smets O14 Hepatobiliary MR contrast: enhanced liver MRI for HCC diagnosis and management Giovanni Morana O15 Role of US elastography and multimodality fusion for managing patients with chronic liver disease and HCC Jeong Min Lee O16 Opportunities and challenges in imaging metastatic disease Hersh Chandarana O17 Diagnosis, treatment monitoring, and follow-up of lymphoma Marius E. Mayerhoefer, Markus Raderer, Alexander Haug O18 Managing high-risk and advanced prostate cancer Matthias Eiber O19 Immunotherapy: imaging challenges Bernhard Gebauer O20 RECIST and RECIST 1.1 Andrea Rockall O21 Challenges of RECIST in oncology imaging basics for the trainee and novice Aslam Sohaib O22 Lymphoma: PET for interim and end of treatment response assessment: a users’ guide to the Deauville Score Victoria S Warbey O23 Available resources Hebert Alberto Vargas O24 ICIS e-portal and the online learning community Dow-Mu Koh O25 Benign lesions that mimic pancreatic cancer Jay P Heiken O26 Staging and reporting pancreatic malignancies Isaac R Francis, Mahmoud, M Al-Hawary, Ravi K Kaza O27 Intraductal papillary mucinous neoplasm Giovanni Morana O28 Cystic pancreatic tumours Mirko D’Onofrio O

  16. Thematic mapping from satellite imagery

    CERN Document Server

    Denègre, J

    2013-01-01

    Thematic Mapping from Satellite Imagery: A Guidebook discusses methods in producing maps using satellite images. The book is comprised of five chapters; each chapter covers one stage of the process. Chapter 1 tackles the satellite remote sensing imaging and its cartographic significance. Chapter 2 discusses the production processes for extracting information from satellite data. The next chapter covers the methods for combining satellite-derived information with that obtained from conventional sources. Chapter 4 deals with design and semiology for cartographic representation, and Chapter 5 pre

  17. Cooperative and cognitive satellite systems

    CERN Document Server

    Chatzinotas, Symeon; De Gaudenzi, Riccardo

    2015-01-01

    Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

  18. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...

  19. Declassified Intelligence Satellite Photographs

    Science.gov (United States)

    ,

    2008-01-01

    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth's land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive. The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  20. Satellites in Canadian broadcasting

    Science.gov (United States)

    Siocos, C. A.

    The involvement of Canadian broadcasting and related enterprises in satellite telecommunications is surveyed. This includes point-to-point transmissions and direct ones to the general public. The mode of such utilizations is indicated in both these cases. For the forthcoming DBS systems the many types of service offerings and utilization concepts under discussion elasewhere are presented as well as the business prospects and regulatory climate offering them.

  1. Neptune: Minor Satellites

    Science.gov (United States)

    Murdin, P.

    2003-04-01

    All but one of Neptune's minor satellites orbit within or just outside its ringsystem; the exception is the distant object Nereid. Some of them are betterdescribed as `mid-sized' rather than `minor', but are included under thisheading as little is known of them. The inner four, with approximatediameters, are Naiad (60 km), Thalassa (80 km), Despina (150 km) and Galatea(160 km). The first three lie...

  2. Satellite Surveillance: Domestic Issues

    Science.gov (United States)

    2010-02-01

    earthquake and tsunami in the Indian Ocean and Hurricane Katrina in 2005, when the NGA provided graphics for “relief efforts that depicted the locations of...that show the damage resulting from an earthquake , fire, flood, hurricane, oil spill, or volcanic eruption.8 Bush Administration Policies...Satellite information has continued to have important civil applications in such disparate areas as the movement of glaciers in Yakutat Bay in Alaska

  3. -AGAn /-GAn AND -ICI SUFFIXES IN TURKISH AND THEIR USAGE IN SÛDÎ’S ANNOTATION TÜRKÇEDE -AGAn /-GAn VE -ICI EKLERİ VE SÛDÎ ŞERHİNDEKİ KULLANIMLARI

    Directory of Open Access Journals (Sweden)

    Mevlüt ERDEM

    2010-07-01

    Full Text Available The suffixes of -AGAn / -GAn used unfrequently in Modern Turkish exhibit some important features in the development of Turkish. In Karakhanid Turkic, the habitual meaning of the verb is formed with -GAn participle and in some cases with -AGAn. This usage increases gradually in Old Anatolian Turkish and Sudi’s annotation. Sudi utilizes the derivation of -AGAn/-GAn used in his time productively in word formation in order to translate the exact meaning of the Persian words into Turkish, which were called sıfat-ı müşebbehe (an adjective formed from a verb. In these derivations, although the habitual meaning of the verbs is stressed, some of them function as participles. On the other hand, Sudi uses Turkish -IcI suffix in order to substitute Persian agent nouns (ism-i fail. The suffix functions as non-finite verbs in some constructions like -AGAn /-GAn suffixes. Türkiye Türkçesinde işlek olmayan -AGAn/-GAn eki Türkçenin gelişiminde önemli özellikler sergiler. Karahanlı Türkçesinde fiildeki süreklilik anlamı -GAn sıfat-fiiliyle birlikte az da olsa -AGAn ekiyle de sağlanır. Bu kullanım EAT eserlerinde ve Sûdî şerhinde artarak devam eder. Sûdî, döneminde hâlâ işlek olarak kullanıldığını anladığımız -AGAn / -GAn’lı türetimleri Farsça sıfat-ı müşebbehe olan kelimelerin Türkçedeki anlamlarını tam olarak vermek için kullanır. Bu türetimlerde fiilin sürekli yapıldığı vurgulansa da bunların bir kısmı sıfat-fiil işleyişindedir. Sûdî, şerhinde ism-i failleri karşılamak için ise -IcI ekinden yararlanır. Bu ek de -AGAn/-GAn ekleri gibi bazı kullanımlarda bitimsiz fiil işleyişindedir.

  4. Communications satellites - The experimental years

    Science.gov (United States)

    Edelson, B. I.

    1983-10-01

    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  5. Tethered satellite design

    Science.gov (United States)

    Manarini, G.

    1986-01-01

    The capability of the satellite to perform a variety of space operations to be accomplished from the shuttle is reviewed considering use of the satellite with man-in-loop and closed loop modes and deployment (toward or away from Earth, up to 100 km), stationkeeping, retrieval and control of the satellite. Scientific payloads are to be used to perform experiments and scientific investigation for applications such as magnetometry, electrodynamics, atmospheric science, chemical release, communications, plasmaphysics, dynamic environment, and power and thrust generation. The TSS-S will be reused for at least 3 missions after reconfiguration and refurbishment by changing the peculiar mission items such as thermal control, fixed boom for experiments, aerodynamic tail for yaw attitude control, external skin, experiments, and any other feature. The TSS-S is to be composed of three modules in order to allow independent integration of a single module and to facilitate the refurbishment and reconfiguration between flights. The three modules are service, auxiliary propulsion, and payload modules.

  6. Heart Monitoring By Satellite

    Science.gov (United States)

    1978-01-01

    The ambulance antenna shown is a specially designed system that allows satellite-relayed two-way communications between a moving emergency vehicle and a hospital emergency room. It is a key component of a demonstration program aimed at showing how emergency medical service can be provided to people in remote rural areas. Satellite communication permits immediate, hospital- guided treatment of heart attacks or other emergencies by ambulance personnel, saving vital time when the scene of the emergency is remote from the hospital. If widely adopted, the system could save tens of thousands of lives annually in the U.S. alone, medical experts say. The problem in conventional communication with rural areas is the fact that radio signals travel in line of sight. They may be blocked by tall buildings, hills and mountains, or even by the curvature of the Earth, so signal range is sharply limited. Microwave relay towers could solve the problem, but a complete network of repeater towers would be extremely expensive. The satellite provides an obstruction-free relay station in space.

  7. Tactical Satellite 3

    Science.gov (United States)

    Davis, T. M.; Straight, S. D.; Lockwook, R. B.

    2008-08-01

    Tactical Satellite 3 is an Air Force Research Laboratory Science and Technology (S&T) initiative that explores the capability and technological maturity of small, low-cost satellites. It features a low cost "plug and play" modular bus and low cost militarily significant payloads - a Raytheon developed Hyperspectral imager and secondary payload data exfiltration provided by the Office of Naval Research. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a potential concept of operations for future acquisitions. The key objectives are rapid launch and on-orbit checkout, theater commanding, and near-real time theater data integration. It will also feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the satellite modular bus initiative. Planned for a late summer 2008 launch, the TacSat-3 spacecraft will collect and process images and then downlink processed data using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. An international program, the United Kingdom Defence Science and Technology Laboratory (DSTL) and Australian Defence Science and Technology Organisation (DSTO) plan to participate in TacSat-3 experiments.

  8. A satellite anemometer

    Science.gov (United States)

    Hanson, W. B.; Heelis, R. A.

    1995-01-01

    This report describes the design, development, and testing of components of a satellite anemometer, an instrument for measuring neutral winds in the upper atmosphere from a satellite platform. The device, which uses four nearly identical pressure sensors, measures the angle of arrival of the bulk neutral flow in the satellite frame of reference. It could also be used in a feedback loop to control spacecraft attitude with respect to the ram velocity direction. We have now developed miniaturized ionization pressure gauges that will work well from the slip flow region near 115 km up to the base of the exosphere, which covers the entire altitude range currently being considered for Tether. Laboratory tests have demonstrated a very linear response to changes in ram angle out to +/- 20 deg. (transverse wind component of 2.7 km s(exp -1)) from the ram, and a monotonic response to out beyond 45 deg. Pitch (vertical wind) and yaw (horizontal wind) can be sampled simultaneously and meaningfully up to 10 Hz. Angular sensitivity of 30 arc seconds (approximately 1 ms(exp -1) is readily attainable, but absolute accuracy for winds will be approximately 1 deg (130 m/s) unless independent attitude knowledge is available. The critical elements of the design have all been tested in the laboratory.

  9. Binary Satellite Galaxies

    CERN Document Server

    Evslin, Jarah

    2013-01-01

    Suggestions have appeared in the literature that the following five pairs of Milky Way and Andromeda satellite galaxies are gravitationally bound: Draco and Ursa Minor, Leo IV and V, Andromeda I and III, NGC 147 and 185, and the Magellanic clouds. Under the assumption that a given pair is gravitationally bound, the Virial theorem provides an estimate of its total mass and so its instantaneous tidal radius. For all of these pairs except for the Magellanic clouds the resulting total mass is 2 to 4 orders of magnitude higher than that within the half light radius. Furthermore in the case of each pair except for Leo IV and Leo V, the estimated tidal radius is inferior to the separation between the two satellites. Therefore all or almost all of these systems are not gravitationally bound. We note several possible explanations for the proximities and similar radial velocities of the satellites in each pair, for example they may have condensed from the same infalling structure or they may be bound by a nongravitatio...

  10. Studies of outer planet satellites, Mercury and Uranus

    Science.gov (United States)

    Mckinnon, William B.; Schenk, Paul M.

    1987-01-01

    Arguments were made, based on geometry, for both an impact and an internal origin for the ancient, partially preserved furrow system of Ganymede. It was concluded that furrows were not concentric, but could be impact related if multiringed structures on icy satellites are initially noncircular. The geometry of the Valhalla ring structure on Callisto was examined in order to assess the circularity of an unmodified ring system. The Ganymede furrow system was remapped to make use of improvements in coordinate control. The least-squares center of curvature for all furrows in the Marius and Galileao Regio is -20.7, and 179.2 degrees. Furrows in Marius and Galileo Regio are reasonably concentric, and are much more circular than previously estimated. The perceived present nonalignment of the assumed originally concentric furrows were used to argue for large-scale lateral motion of dark terrain blocks in Ganymede's crust, presumably in association with bright terrain formation., The overall alignment of furrows as well as the inherent scatter in centers of curvature from subregions of Galileo and Marius do not support this hypothesis.

  11. The cardiovascular pharmacology of ICI 170777 ((6RS)-6-methyl-5-(pyrid-4-yl)-3H,6H-1,3,4- thiadiazin-2-one) a novel compound with positive inotropic and vasodilator effects.

    Science.gov (United States)

    Collis, M. G.; Keddie, J. R.; Rouse, W.

    1989-01-01

    1. This paper describes the cardiovascular effects of ICI 170777, a novel compound which enhances cardiac contractility and causes arterial and venous dilatation. 2. The positive inotropic effects of ICI 170777 on the heart were demonstrated by an increase in left ventricular dP/dtmax in the anaesthetized and conscious dog, and by an increase in tension development in isolated papillary muscles from the cat. 3. In the anaesthetized dog, the positive inotropic effects of ICI 170777 and of isoprenaline were attenuated by atenolol (5 mg kg-1, i.v.). Atenolol displaced the dose-response curve to ICI 170777 to the right by 4 fold but displaced the isoprenaline dose-response curve to the right by 247 fold. In vitro, however, atenolol (10 microM) had no significant effect on the positive inotropic response to ICI 170777. In the ganglion-blocked anaesthetized dog, infusion of a low dose of ICI 170777 which had no effect on the basal left ventricular dP/dtmax, selectively potentiated the positive inotropic effects of isoprenaline. These results indicate that ICI 170777 has both a non-adrenoceptor-mediated positive inotropic effect on the heart and also facilitates the beta-adrenoceptor-mediated control of contractility. 4. In the denervated and perfused hind-limb of the dog, ICI 170777 reduced arterial perfusion pressure and increased limb circumference at a constant arterial flow and venous pressure. This indicates that ICI 170777 has direct dilator actions on both arterial and venous vessels. In this preparation, diazoxide exerted an arterial selective vasodilator effect and sodium nitroprusside was a relatively selective venous dilator.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2758224

  12. Predictions and Tests of the "Late Noachian Icy Highlands" Climate Model: Can Evidence for Fluvial/Lacustrine Systems Be Reconciled?

    Science.gov (United States)

    Head, J. W., III

    2016-12-01

    Improved 3D global simulations (GCMs) of the early martian climate have found that for atmospheric pressures greater than a fraction of a bar, atmospheric-surface thermal coupling occurs and the adiabatic cooling effect (ACE) causes temperatures in the southern uplands to fall significantly below the global average. Long-term climate evolution simulations indicate that in these circumstances, water ice is transported to the highlands from low-lying regions for a wide range of obliquities. Conditions are too cold (MAT 225 K) to permit the presence of long-term surface liquid water, including streams, lakes and oceans. The LNIH equilibrium state predicts: 1) a global permafrost layer, 2) a horizontally stratified hydrological cycle/system, 3) thick ice deposits in the southern uplands, 4) an extended water ice cap on the southern pole, and 5) no rainfall, streams lakes or oceans. The majority of these predictions are in direct conflict with the observed fluvial/lacustrine geologic record. Can non-equilibrium conditions in a LNIH scenario explain these conflicts by transient heating and melting of the LNIH? As steps in the comprehensive testing of this "Late Noachian Icy Highlands" (LNIH) model we explore the predictions for geologic settings and processes in both equilibrium and non-equilibrium climate states. We assess the following sources of disequilibrium: 1) Top-down heating and melting: a) impact cratering, b) extrusive/explosive volcanism, and c) short-term emission of greenhouse gases. 2) Bottom up heating and melting: a) enhanced regional-global geothermal gradients, and b) thick ice accumulation to cause/sustain basal melting, wet-based glaciation and runoff. We assess these disequilibrium mechanisms in terms of: 1) the altitude dependence of melting, 2) melting duration, 3) volumes of meltwater produced, 4) predicted locations of meltwater production, and 6) comparison to the distribution of fluvial/lacustrine features. We find that the Late Noachian Icy

  13. Satellite Upper Air Network (SUAN)

    Science.gov (United States)

    Reale, Tony L.; Thorne, Peter

    2004-10-01

    During the past 20 years of NOAA operational polar satellites, it has become evident that a growing problem concerning their utilization in Climate and also Numerical Weather Prediction (NWP) applications are the systematic errors and uncertainties inherent in the satellite measurements. Similar arguments can be made for global radiosonde observations. These uncertainties are often larger than the sensitive signals and processes, that satellite and radiosonde measurements are designed to reveal, particularly in the realm of climate. Possible strategies to quantify and compensate for these problems include the analysis of satellite overlap data and/or available collocations of satellite and ground truth (radiosonde) observations. However, overlap observations are typically not available except in extreme polar regions and current sampling strategies for compiling collocated radiosonde and satellite observations are insufficient, further compounding the inherent uncertainties in the ground-truth radiosonde data. A Satellite Upper Air Network is proposed to provide reference radiosonde launches coincident with operational polar satellite(s) overpass. The SUAN consist of 36 global radiosonde stations sub-sampled from the Global Upper Air Network (GUAN), and is designed to provide a robust, global sample of collocated radiosonde and satellite observations conducive to the monitoring and validation of satellite and radiosonde observations. The routine operation of such a network in conjunction with operational polar satellites would provide a long-term of performance for critical observations of particular importance for climate. The following report presents a candidate network of 36 upper-air sites that could comprise a SUAN. Their selection along with the mutual benefit across the satellite, radiosonde, climate, numerical weather prediction (NWP) and radiative transfer (RT) model areas are discussed.

  14. Exposure age of Saturn's A and B rings, and the Cassini Division as suggested by their non-icy material content

    Science.gov (United States)

    Zhang, Z.; Hayes, A. G.; Janssen, M. A.; Nicholson, P. D.; Cuzzi, J. N.; de Pater, I.; Dunn, D. E.

    2017-09-01

    Saturn's rings are composed primarily of water ice with a small fraction of non-icy constituents that are likely both intrinsic and extrinsic in origin. The intrinsic material is thought to be characteristic of the ring progenitor, while the extrinsic material is derived from the continual stream of hypervelocity impacting micrometeoroids that pollute the rings over time. Thus constraining these relative volume fractions and their radial distribution provides a powerful tool by which one can reveal clues about the rings' ultimate origin and age. In this companion to our first paper for the C ring (Zhang et al., 2017), we present new measurements of the non-icy material fraction in Saturn's B ring, Cassini Division and A ring as determined from microwave radiometry observations acquired by the Cassini spacecraft. We investigate the near-zero azimuthal angle observations and demonstrate a radially varying scattering phase function for B ring particles which transitions from half-Mie-half-isotropic in the inner and outer B ring to purely isotropic in the middle B ring. This variation follows the trend of the optical depth in that as the optical depth increases, more particles scatter isotropically. In the A ring radially inward of the Encke gap, we find that the phase function can vary from purely isotropic for 55% porous particles to a combination of 30% Mie/70% isotropic for porosities of 90%, while outwards of the Encke gap particles are most likely 90% porous and scatter light isotropically. We derive the non-icy material fractions, assuming silicate as the non-icy material, and show that there is a significant dependence on the assumed porosity in the B ring, but the radial distribution follows the same trend as the optical depth. Owing to the B ring's high opacity (i.e. high optical depth but low surface density), the particles there are likely to have 85%-90% porosity, with corresponding non-icy volume fractions of ∼0.3%-0.5% in the inner and outer B ring

  15. Radio broadcasting via satellite

    Science.gov (United States)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  16. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  17. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  18. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  19. Future communications satellite applications

    Science.gov (United States)

    Bagwell, James W.

    1992-01-01

    The point of view of the research is made through the use of viewgraphs. It is suggested that future communications satellite applications will be made through switched point to point narrowband communications. Some characteristics of which are as follows: small/low cost terminals; single hop communications; voice compatible; full mesh networking; ISDN compatible; and possible limited use of full motion video. Some target applications are as follows: voice/data networks between plants and offices in a corporation; data base networking for commercial and science users; and cellular radio internodal voice/data networking.

  20. HETE Satellite Power Subsystem

    OpenAIRE

    1993-01-01

    The HETE (High-Energy Transient Experiment) satellite a joint project between MIT's Center for Space Research and AeroAstro. is a high-energy gamma-ray burst/X-Ray/UV observatory platform. HETE will be launched into a 550 km circular orbit with an inclination of 37.7°, and has a design lifetime of 18 months. This paper presents a description of the spacecraft's power subsystem, which collects, regulates, and distributes power to the experiment payload modules and to the various spacecraft sub...

  1. A Submersible, Off-Axis Holographic Microscope for Detection of Microbial Motility and Morphology in Aqueous and Icy Environments.

    Directory of Open Access Journals (Sweden)

    Christian A Lindensmith

    Full Text Available Sea ice is an analog environment for several of astrobiology's near-term targets: Mars, Europa, Enceladus, and perhaps other Jovian or Saturnian moons. Microorganisms, both eukaryotic and prokaryotic, remain active within brine channels inside the ice, making it unnecessary to penetrate through to liquid water below in order to detect life. We have developed a submersible digital holographic microscope (DHM that is capable of resolving individual bacterial cells, and demonstrated its utility for immediately imaging samples taken directly from sea ice at several locations near Nuuk, Greenland. In all samples, the appearance and motility of eukaryotes were conclusive signs of life. The appearance of prokaryotic cells alone was not sufficient to confirm life, but when prokaryotic motility occurred, it was rapid and conclusive. Warming the samples to above-freezing temperatures or supplementing with serine increased the number of motile cells and the speed of motility; supplementing with serine also stimulated chemotaxis. These results show that DHM is a useful technique for detection of active organisms in extreme environments, and that motility may be used as a biosignature in the liquid brines that persist in ice. These findings have important implications for the design of missions to icy environments and suggest ways in which DHM imaging may be integrated with chemical life-detection suites in order to create more conclusive life detection packages.

  2. Manchester Ice Nucleus Counter (MINC measurements from the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007

    Directory of Open Access Journals (Sweden)

    H. M. Jones

    2011-01-01

    Full Text Available An ice nucleus counter was developed and constructed to enable investigation of potential ice nucleating materials. The Manchester Ice Nucleus Chamber (MINC is a concentric-cylinder continuous flow diffusion chamber (CFDC. A full explanation of the MINC instrument is given here, along with first results and a comparison to an established instrument of similar design (Colorado State University CFDC during sampling of common ice nucleating aerosols at the 2007 International workshop on Comparing Ice nucleation Measuring Systems (ICIS-2007. MINC and CSU-CFDC detected the onset of ice nucleation under similar conditions of temperature and supersaturation for several different types of ice nuclei. Comparisons of the ratio of ice nuclei to total aerosol concentrations as a function of supersaturation with respect to water (SSw showed agreement within one order of magnitude. Possible reasons for differences between the two instruments relating to differences in their design are discussed, along with suggestions to future improvements to the current design.

  3. Synthesis and characterization of peptides after high-energy impact on the icy matrix: Preliminary step for further UV-induced formation

    Science.gov (United States)

    Gontareva, Natalia B.; Kuzicheva, Evgenia A.; Shelegedin, Vladimir N.

    2009-04-01

    In the interstellar medium, the most probable source of organic molecules could be non-equilibrium processes driven by photons, cosmic rays, shock waves and solid bodies' collisions. The dense cold phase of ISM host icy dust grains - important chemical catalyst during its life cycle. Such particles consist of mineral core composed by silicate or olivine admixed with metal sulfides and oxides, with the water-icy envelope containing organic molecules. Organic molecules in the ISM evolve and become later incorporated in solar system material (comets and meteorites). The formation of polypeptides from single amino acids was traced in simulation experiments representing the inner structure of icy dust grains. Experimental chamber was irradiated at subzero temperatures at the dosage of 2.54 kRad/min. Solid frozen solutions of Gly and Phe were taken as the experimental samples inserted into the metal tube kept at subzero temperatures in the presence of liquid nitrogen. Formation of di- and tri-peptides was demonstrated after applying mass-spectrometry and high performance liquid chromatography (HPLC) techniques. Having polypeptides within the icy matrix, dust grains with ice mantles are transported to warm, dense and active protostellar regions, where ultraviolet irradiation may become important and alter the grain composition. Furthermore UVC radiation may contribute to the formation of additional amounts of polypeptides, since short-wave photons are totally adsorbed by a thin outer layer. This presumption coincides with our previous investigations concerning UV impact on prebiotic formation of the main biological molecules. Combination of two irradiation types in different stages of interstellar flight could compensate the effects of low reagents concentration and temperature. Since the primordial Earth had no atmosphere, the natural carriers could get freely onto its surface and thus raise the concentration of organic molecules.

  4. The TAOS/STEP Satellite

    OpenAIRE

    Edwards, David; Hosken, Robert

    1995-01-01

    The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous N...

  5. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  6. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Index of Watershed Integrity / Index of Catchment Integrity (IWI/ICI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset represents the Index of Watershed Integrity / Index of Catchment Integrity (IWI/ICI) within individual local NHDPlusV2 catchments and upstream,...

  7. Digital Shoreline Analysis System (DSAS) version 4.3 Transects with Short-Term End Point Rate Calculations for the Sheltered East Chukchi Sea coast of Alaska between Point Barrow and Icy Cape

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of short-term (~33 years) shoreline change rates for the north coast of Alaska between Point Barrow and Icy Cape. Rate calculations were...

  8. Trends in mobile satellite communication

    Science.gov (United States)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  9. Magnetic Satellite Missions and Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Kotsiaros, Stavros

    2011-01-01

    Although the first satellite observations of the Earth’s magnetic field were already taken more than 50 years ago, continuous geomagnetic measurements from space are only available since 1999. The unprecedented time-space coverage of this recent data set opened revolutionary new possibilities...... for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...... exploration of Earth’s magnetic field with satellites....

  10. Satellite Communications: The Indian Scenario

    Directory of Open Access Journals (Sweden)

    Dr. Ranjit Singh

    2014-05-01

    Full Text Available India has launched as many as 73 Indian satellites as of today since its first attempt in 1975. Besides serving traditional markets of telephony and broadcasting, satellites are on the frontiers of advanced applications as telemedicine, distance learning, environment monitoring, remote sensing, and so on. Satellite systems are optimized for services such as Internet access, virtual private networks and personal access. Costs have been coming down in recent years to the point where satellite broadband is becoming competitive. This article is an attempt to view this important topic from Indian perspective. India’s Project GAGAN, GPS Aided Geo Augmented Navigation is discussed.

  11. Business Use of Satellite Communications.

    Science.gov (United States)

    Edelson, Burton I.; Cooper, Robert S.

    1982-01-01

    Reviews business communications development and discusses business applications of satellite communications, system technology, and prospects for future developments in digital transmission systems. (JN)

  12. The Spectral Classes of the Saturnian System Ices: Rings and Satellites Observations by Cassini-VIMS

    Science.gov (United States)

    Filacchione, G.; Capaccioni, F.; Tosi, F.; Coradini, A.; Cerroni, P.; Clark, R. N.; Cuzzi, J. N.; Nicholson, P. D.; Buratti, B. J.; Brown, R. H.; Cruikshank, D. P.; Jaumann, R.; Hedman, M. M.

    2008-12-01

    The entire population of the Saturnian system ices was investigated by VIMS (Visual and Infrared Mapping Spectrometer) experiment on board Cassini spacecraft. By the end of the nominal mission a very large dataset of hyperspectral data had been collected in the spectral range 0.35-5.0 micron, which includes the regular satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus, Phoebe), minor moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso) and rings. In this work we present an analysis of spectrophotometric indicators selected to describe the properties of the ices (I/F continuum levels, visible spectral slopes, band depths and positions), and which were retrieved from about 1500 full-disk observations of satellites as well as from mosaics of the main rings (A, B, C, CD, F) sampled with a resolution of 125 km/pixel along the radial axis. This comparative method allows us to highlight the spectral differences in this population of objects orbiting in the Saturnian system. In particular we have retrieved the distribution of the water ice abundance, which varies between the almost pure icy surfaces of Enceladus and Calypso to the carbon dioxide- and organic-rich Hyperion, Iapetus and Phoebe. Noteworthy is that a significant dichotomy is observed between the two co-orbital moons Epimetheus and Janus, possibly indicating a different origin and evolutionary process: while the first shows a very red visible spectrum (similar to Hyperion), the second has more neutral visible colors, making it a very peculiar object in the Saturnian system. Rings have very peculiar spectral differences when compared with the icy satellites: in the visible range their spectra are characterized by a spectral knee at bluer wavelengths (at about 520 nm compared to 550 nm on satellites); in the infrared range the 1.5-2.0 micron water ice band depths are in general deeper across the A and B rings, indicative of a larger fraction of pure water ice in comparison to

  13. Declassified Intelligence Satellite Photographs

    Science.gov (United States)

    ,

    2008-01-01

    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth’s land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive.The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  14. The power relay satellite

    Science.gov (United States)

    Glaser, Peter E.

    The availability and use of renewable energy sources compatible with reducing risks to the global environment are key to sustainable development. Large-scale, renewable energy resources at undeveloped or underutilized sites are potentially available on several continents. The Power Relay Satellite (PRS) concept has the potential to access these remote energy resources by coupling primary electricity generation from terrestrial transmission lines. A global PRS network can be envisioned to provide a high degree of flexibility for supplying energy demands worldwide with wireless power transmitted from sites on Earth to geosynchronous orbit and then reflected to receivers interfacing with terrestrial power transmision networks. Past developments in wireless power transmission (WPT) are reviewed and recent successful results are noted. The origins of the PRS concept, and a possible configuration are discussed, principles of WPT at microwave frequencies, functional requirements, and system design contraints are outlined, and space transportation concepts presented. PRS assessments including applicable technologies, economic projections, and societal issues are highlighted. It is concluded that the PRS provides a promising option to access renewable resources at great distances from major markets, and represents an important stage in the future development in the future of solar power satellites.

  15. Astronomers Find World with Thick, Inhospitable Atmosphere and an Icy Heart

    Science.gov (United States)

    2009-12-01

    is a planet orbiting a star other than the Sun. [2] The star GJ1214 is five times smaller than our Sun and intrinsically three hundred times less bright. [3] Corot-7b is the smallest and fastest-orbiting exoplanet known and has a density quite similar to the Earth's, suggesting a solid, rocky world. Discovered by the CoRoT satellite as a transiting object, its true nature was revealed by HARPS (eso0933). [4] The MEarth project uses an armada of eight small telescopes each with a diameter of 40 cm, located on top of Mount Hopkins, Arizona, USA. MEarth looks for stars that change brightness. The goal is to find a planet that crosses in front of, or transits, its star. During such a mini-eclipse, the planet blocks a small portion of the star's light, making it dimmer. NASA's Kepler mission also uses transits to look for Earth-sized planets orbiting Sun-like stars. However, such systems dim by only one part in ten thousand. The higher precision required to detect the drop means that such worlds can only be found from space. In contrast, a super-Earth transiting a small, red dwarf star yields a greater proportional decrease in brightness and a stronger signal that is detectable from the ground. More information This research was presented in a paper appearing this week in Nature ("A Super-Earth Transiting a Nearby Low-Mass Star", by David Charbonneau et al.). The team is composed of David Charbonneau, Zachory K. Berta, Jonathan Irwin, Christopher J. Burke, Philip Nutzman, Lars Buchhave, David W. Latham, Ruth A. Murray-Clay, Matthew J. Holman, and Emilio E. Falco (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), Christophe Lovis, Stephane Udry, Didier Queloz, Francesco Pepe, and Michel Mayor (Observatoire de l'Université de Genève, Switzerland), Xavier Bonfils, Xavier Delfosse, and Thierry Forveille (University Joseph Fourier - Grenoble 1/CNRS, LOAG, Grenoble, France), and Joshua N. Winn (Kavli Institute for Astrophysics and Space Research, MIT, Cambridge

  16. Chaotic motion of Europa and Ganymede and the Ganymede-Callisto dichotomy

    Science.gov (United States)

    Tittemore, William C.

    1990-01-01

    Europa and Ganymede may have undergone an episode of chaotic motion before the establishment of the current Laplace resonance involving the three inner GAlilean satellites. During this episode, the orbital eccentricities of both satellites may have increased dramatically. As a result, the mechanical stresses due to tidal deformation of the satellites' icy lithospheres may have been large enough to result in extensive fracturing, and tidal heating may have melted water ice in the mantles of both satellites, triggering the geological activity that has modified their surfaces since the heavy cratering period. The tidal effects on Ganymede during this episode provide an explanation of the dichotomy between it and Callisto, which have similar bulk properties but very different geological histories.

  17. Inter-satellite links for satellite autonomous integrity monitoring

    Science.gov (United States)

    Rodríguez-Pérez, Irma; García-Serrano, Cristina; Catalán Catalán, Carlos; García, Alvaro Mozo; Tavella, Patrizia; Galleani, Lorenzo; Amarillo, Francisco

    2011-01-01

    A new integrity monitoring mechanisms to be implemented on-board on a GNSS taking advantage of inter-satellite links has been introduced. This is based on accurate range and Doppler measurements not affected neither by atmospheric delays nor ground local degradation (multipath and interference). By a linear combination of the Inter-Satellite Links Observables, appropriate observables for both satellite orbits and clock monitoring are obtained and by the proposed algorithms it is possible to reduce the time-to-alarm and the probability of undetected satellite anomalies.Several test cases have been run to assess the performances of the new orbit and clock monitoring algorithms in front of a complete scenario (satellite-to-satellite and satellite-to-ground links) and in a satellite-only scenario. The results of this experimentation campaign demonstrate that the Orbit Monitoring Algorithm is able to detect orbital feared events when the position error at the worst user location is still under acceptable limits. For instance, an unplanned manoeuvre in the along-track direction is detected (with a probability of false alarm equals to 5 × 10-9) when the position error at the worst user location is 18 cm. The experimentation also reveals that the clock monitoring algorithm is able to detect phase jumps, frequency jumps and instability degradation on the clocks but the latency of detection as well as the detection performances strongly depends on the noise added by the clock measurement system.

  18. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    Science.gov (United States)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  19. Multicast Routing in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    郭惠玲; 宋姝; 李磊; 刘志涛; 郭鹏程

    2004-01-01

    There are some problems in the dual-layer satellite MPLs metworks to be composed of LEO and MEO. In order to solve the problems, this paper presents a plan by means of unicast LSP to implement multicast in the dual-layer satellite MPLs networks. It has advantages of saving space and reducing extra charge.

  20. Magnetic Satellite Missions and Data

    DEFF Research Database (Denmark)

    Olsen, Nils; Kotsiaros, Stavros

    2011-01-01

    for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...