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Sample records for jupiter icy moons

  1. Europa--Jupiter's Icy Ocean Moon

    NASA Technical Reports Server (NTRS)

    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.

  2. The Icy Moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    The Galilean satellites formed in a nebula of dust and gas that surrounded Jupiter toward the end of the formation of the giant planet itself. Their diverse initial compositions were determined by conditions in the circum-jovian nebula, just as the planets' initial properties were governed by their formation within the circum-solar nebula. The Galilean satellites subsequently evolved under the complex interplay of orbital and geophysical processes, which included the effects of orbital resonances, tides, internal differentiation, and heat. The history and character of the satellites can be inferred from consideration of the formation of planets and the satellites, from studies of their plausible orbital evolution, from measurements of geophysical properties, especially gravitational and magnetic fields, from observations of the compositions and geological structure of their surfaces, and from geophysical modeling of the processes that can relate these lines of evidence. The three satellites with large water-ice components, Europa, Ganymede, and Callisto are very different from one another as a result of the ways that these processes have played out in each case. Europa has a deep liquid-water ocean with a thin layer of surface ice, Ganymede and Callisto likely have relatively thin liquid water layers deep below their surfaces, and Callisto remains only partially differentiated, with rock and ice mixed through much of its interior. A tiny inner satellite, Amalthea, also appears to be largely composed of ice. Each of these moons is fascinating in its own right, and the ensemble provides a powerful set of constraints on the processes that led to their formation and evolution.

  3. The Jupiter Icy Moons Orbiter reference trajectory

    NASA Technical Reports Server (NTRS)

    Whiffen, Gregory J.; Lam, Try

    2006-01-01

    The proposed NASA Jupiter Icy Moons Orbiter (JIMO) mission would have used a single spacecraft to orbit Callisto, Ganymede, and Europa in succession. The enormous Delta-Velocity required for this mission (nearly [25 km/s]) would necessitate the use of very high efficiency electric propulsion. The trajectory created for the proposed baseline JIMO mission may be the most complex trajectory ever designed. This paper describes the current reference trajectory in detail and describes the processes that were used to construct it.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. A Power Conversion Concept for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2003-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission under development by the Office of Space Science at NASA Headquarters. ITMO is examining the potential of Nuclear Electric Propulsion (NEP) technology to efficiently deliver scientific payloads to three Jovian moons: Callisto, Ganymede, and Europa. A critical element of the NEP vehicle is the reactor power system, consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD). The emphasis of this paper is on the non-nuclear elements of the reactor power system.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Jupiter Icy Moons Tidal Signatures and Ocean Mapping from Orbit

    NASA Technical Reports Server (NTRS)

    Wu, X.; Bar-Server, Y. E.; Folkner, W. M.; Williams, J. G.; Zumberge, J. F.

    2003-01-01

    Following the Galileo spacecraft encounters with Europa, Ganymede, and Callisto, evidence emerged suggesting that these Galilean moons of Jupiter may have liquid oceans underneath their icy shells. Detection of the oceans on one or all three moons will have profound implications on probability of life beyond the Earth. The icy satellites also have tidal environments that are among the strongest in the solar system. The leading time-varying tidal forcing term on the surface of Europa is at least 9 times larger than those on the inner planets. Tidal forcing on the surfaces of Ganymede and Callisto are about 10% and 7%, respectively, of that on Europa. Since a planetary body with internal fluid deforms more than an otherwise solid body, tidal measurements offer exciting opportunities to detect the oceans.

  9. Jupiter Icy Moons Orbiter interplanetary injection period analysis

    NASA Technical Reports Server (NTRS)

    Kowalkowski, Theresa D.; Kangas, Julie A.; Parcher, Daniel W.

    2006-01-01

    This paper investigates the sensitivity of the planned Jupiter Icy Moons Orbiter mission to variations in interplanetary injection date, magnitude, and direction, starting in a low-Earth assembly orbit. These results are used to determine the frequency and number of injection opportunities from a processing assembly obit. It is shown that the use of a low-thrust propulsion system with a nuclear-electric power source would allow the interplanetary trajectory performance to be relatively insensitive to variations in injection conditions. This result yields many injection opportunities due to the long injection period and consecutive orbits with favorable geometry.

  10. Radio Science Concepts and Approaches for Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    Radio Science experiments have been conducted on most deep space missions leading to numerous scientific discoveries. A set of concepts and approaches 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. Measurements are identified that utilize the spacecraft's telecommunication system. Additional instruments can augment these measurements in order to leverage observational synergies. Experiments are also offered for the purpose of investigating the atmospheres and surfaces of the satellites.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Ganymede Europa Neutral Imaging Experiment at the Jupiter's icy moons

    NASA Astrophysics Data System (ADS)

    Milillo, A.; Orsini, S.; Plainaki, C.; DeAngelis, E.; Argan, A.; Fierro, D.; Vertolli, N.; Danduras, I.; Selci, S.; Leoni, R.; Sheer, J.

    2012-04-01

    GENIE (Ganymede Europa Neutral Imaging Experiment) (energy range 10 eV - 10 keV) is a high-angular-resolution detector, based on the ToF technique. Its objective is to map the origin sites of the most energetic neutral particles of the icy moons' exospheres, in order to investigate the interaction between the surface and the environment. The investigation of plasma interaction with the Jupiter's moons and the processes responsible for surface space weathering is one of the coolest topics of the proposed Cosmic Vision mission JUICE since it directly relates to energy exchange within the Jupiter's system, to the moon evolution and finally to the habitability in the harsh radiative environment. Icy surfaces of the Jupiter's moons are continuously irradiated by intense ion fluxes of H+, O+ and S+ in the energy range from keV to MeV. These ions are expected to impact the moon icy surface producing relevant and observable effects such as particles release and chemical and structural modifications of the surface. In particular, the plasma impacting onto the surface causes, via ion-sputtering, radiolysis and backscattering processes, release of neutrals that constitute the exospheres. The energy spectrum of this particle population peaks in the eV range with a non-negligible tail up to hundred eVs. The knowledge of the effectiveness of these processes in this environment is important in order to understand the evolution of the moons and their interactions within the Jupiter's system. The detection of neutral atoms above few 10 eVs (LENA) is a way to univocally relate the exosphere to surface features and to monitor instantaneously the effect of plasma precipitation onto the surface. Thus, GENIE is fully complementary to INM spectrometer, devoted to infer exospheric composition and density. Coupled measurements of LENA and gas composition will improve our knowledge in surface release mechanisms. The observation of LENA at different latitudes and longitudes, resulting in a 2

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

    NASA Astrophysics Data System (ADS)

    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

  14. JUICE: a European mission to Jupiter and its icy moons

    NASA Astrophysics Data System (ADS)

    Titov, D.; Erd, C.; Duvet, L.; Wielders, A.; Torralba-Elipe, I.; Altobelli, N.

    2013-09-01

    JUICE (JUpiter ICy moons Explorer) is the first L-class mission selected for the ESA's Cosmic Vision programme 2015-2025 which has just entered the definition phase. JUICE will perform detailed investigations of Jupiter and its system in all their inter-relations and complexity with particular emphasis on Ganymede as a planetary body and potential habitat. Investigations of Europa and Callisto will complete a comparative picture of the Galilean moons. By performing detailed investigations of Jupiter's system, JUICE will address in depth two key questions of the ESA's Cosmic Vision programme: (1) What are the conditions for planet formation and the emergence of life? and (2) How does the Solar System work? The overarching theme for JUICE has been formulated as: 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 comprehensive multidisciplinary investigation of the Jupiter system as an archetype for gas giants including exoplanets. 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 and their response to the solar wind will be

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

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  17. Planetary protection for the Jupiter Icy Moons Orbiter

    NASA Astrophysics Data System (ADS)

    Gershman, R.; Kohlhase, C.; Koukol, R.

    NASA is developing plans for an ambitious mission to orbit three planet-sized moons of Jupiter -- Callisto, Ganymede and Europa -- which may harbor vast oceans beneath their icy surfaces. The mission, called the Jupiter Icy Moons Orbiter (JIMO), would orbit each of these moons for extensive investigations of their makeup, their history and their potential for sustaining life. JIMO has been identified as the first space science mission to potentially incorporate the revolutionary nuclear power and propulsion capability being developed by NASA's Project Prometheus. Planetary protection (PP) requirements for JIMO are expected to be based on a recommendation by the Space Studies Board (SSB) of the U.S. National Research Council that in any one mission the probability of contaminating a Europan ocean with a viable Earth organism should be less than 10-4. The SSB stated that calculation of this probability should, as a minimum, take into account the following: bioburden at launch, cruise survival of the organisms, organism survival in the radiation environment adjacent to Europa, probability of landing at a geologically active site on Europa, the mechanisms of transfer of the organisms to the Europan subsurface, and organism survival and proliferation before, during, and after subsurface transfer. This presentation reports on preliminary assessment of these factors by the JIMO Project and on work in progress aimed at finding a design capable of meeting planetary protection goals for Europa with the lowest cost and risk impacts for the project. This design will potentially include: credit for sterilizing effects of in-flight radiation, pre-launch sterilization with isolation from recontamination for spacecraft elements protected from the radiation environment, identification of quarantine orbits within the Jovian system providing long term stability, providing high system reliability against failure modes that could lead to surface impact, and assuring separation of the

  18. A Power Conversion Concept for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2003-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission is currently under study by the Office of Space Science under the Project Prometheus Program. JIMO is examining the use of Nuclear Electric Propulsion (NEP) to carry scientific payloads to three Jovian moons. A potential power system concept includes dual 100 kWe Brayton converters, a deployable pumped loop heat rejection subsystem, and a 400 Vac Power Management and Distribution (PMAD) bus. Many trades were performed in aniving at this candidate power system concept. System-level studies examined design and off-design operating modes, determined startup requirements, evaluated subsystem redundancy options, and quantified the mass and radiator area of reactor power systems from 20 to 200 kWe. In the Brayton converter subsystem, studies were performed to investigate converter packaging options, and assess the induced torque effects on spacecraft dynamics due to rotating machinery. In the heat rejection subsystem, design trades were conducted on heat transport approaches, material and fluid options, and deployed radiator geometries. In the PMAD subsystem, the overall electrical architecture was defined and trade studies examined distribution approaches, voltage levels, and cabling options.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    We present a 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 subsurface ocean depth along with the dielectric properties of the ice shell. The technique is complementary to ice penetrating radar measurements in that it works best where interference due to Jupiter's strong decametric emission is the strongest.

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

    NASA Astrophysics Data System (ADS)

    Romero-Wolf, A.; Vance, S.; Maiwald, F.; Ries, P. A.; Liewer, K.

    2014-12-01

    We present a 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 subsurface ocean depth along with the dielectric properties of the ice shell. The technique is complementary to ice penetrating radar measurements in that it works best where interference due to Jupiter's strong decametric emission is the strongest.

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

    NASA Technical Reports Server (NTRS)

    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).

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Electric Propulsion Technology Development for the Jupiter Icy Moons Orbiter Project

    NASA Technical Reports Server (NTRS)

    2004-01-01

    During 2004, the Jupiter Icy Moons Orbiter project, a part of NASA's Project Prometheus, continued efforts to develop electric propulsion technologies. These technologies addressed the challenges of propelling a spacecraft to several moons of Jupiter. Specific challenges include high power, high specific impulse, long lived ion thrusters, high power/high voltage power processors, accurate feed systems, and large propellant storage systems. Critical component work included high voltage insulators and isolators as well as ensuring that the thruster materials and components could operate in the substantial Jupiter radiation environment. A review of these developments along with future plans is discussed.

  4. Radar Sounding for Planetary Subsurface Exploration: Translating the Mars Experience to Jupiter's Icy Moons

    NASA Astrophysics Data System (ADS)

    Plaut, J.

    2015-12-01

    Exploration of the subsurface of Mars using radar sounding began with MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) on Mars Express in 2005 and continued with SHARAD (Shallow Radar) on Mars Reconnaissance Orbiter in 2006. These instruments have been operating continuously since, providing a rich legacy of science return and observational experience in the highly variable environments and target sets at Mars. New missions to the icy moons of Jupiter, ESA's JUICE (Jupiter Icy Moon Explorer) and NASA's Europa Mission, will both carry radar sounders to probe the subsurface of several of the icy moons (Ganymede, Europa and Callisto by JUICE; Europa by the Europa Mission). The success of the Mars sounders demonstrated the scientific value of the technique and provided confidence that sounding of the icy moons is a promising endeavor. Icy targets at Mars have proven especially amenable to penetration by radar sounding. The polar layered deposits of Mars have been probed to their base (2-4 km deep) by MARSIS, operating at frequencies of 1.3-5.5 MHz. SHARAD, operating with a wider bandwidth at 15-25 MHz, provides higher vertical resolution that allows detection and imaging of fine details of interior layering in the ice deposits. The sounder planned for the Europa mission, REASON (Radar for Europa Assessment and Sounding, Ocean to Near-Surface), will utilize simultaneous dual frequency signals to obtain complementary deep sounding and high-vertical-resolution shallow observations. Co-located observations by MARSIS and SHARAD also demonstrate that high surface roughness (relative to the radar wavelength) affects the strength of the penetrating signals, and thus the capability to detect deep or low-contrast subsurface interfaces. The icy moon sounders' wavelengths were selected, in part, to mitigate against this degradation of signals by the anticipated rough surfaces of Jupiter's moons. This paper will discusss these and other examples of lessons

  5. JUpiter ICy moons Explorer (juice): AN ESA L-Class Mission Candidate to the Jupiter System

    NASA Astrophysics Data System (ADS)

    Dougherty, M. K.; Grasset, O.; Erd, C.; Titov, D.; Bunce, E. J.; Coustenis, A.; Blanc, M.; Coates, A. J.; Drossart, P.; Fletcher, L.; Hussmann, H.; Jaumann, R.; Krupp, N.; Prieto-Ballesteros, O.; Tortora, P.; Tosi, F.; Van Hoolst, T.

    2012-04-01

    the first subsurface observations of this icy moon, including the first determination of the minimal thickness of the icy crust over the most recently active regions. JUICE will determine the characteristics of liquid-water oceans below the icy surfaces of the moons. This will lead to an understanding of the possible sources and cycling of chemical and thermal energy, allow investigation of the evolution and chemical composition of the surfaces and of the subsurface oceans, and enable an evaluation of the processes that have affected the satellites and their environments through time. The study of the diversity of the satellite system will be enhanced with additional information gathered remotely on Io and smaller moons. The mis-sion will also focus on characterising the diversity of processes in the Jupiter system which may be required in order to provide a stable environment at Ganymede, Europa and Callisto on geologic time scales, including gravitational coupling between the Galilean satellites and their long term tidal influence on the system as a whole. Focused stud-ies of Jupiter's atmosphere, and magnetosphere and their interaction with the Galilean satellites will further enhance our understanding of the evolution and dynamics of the Jovian system. The circulation, meteorology, chemistry and structure of Jupiter will be studied from the cloud tops to the thermosphere. These observations will be attained over a sufficiently long temporal baseline with broad latitudinal coverage to investigate evolving weather systems and the mechanisms of transporting energy, momentum and material between the different layers. 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 and their response to the solar wind will be elucidated.

  6. A passive probe for subsurface oceans and liquid water in Jupiter's icy moons

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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 3000 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 transmitter failure. The interferometric reflectometer could operate with electrically short antennas, thus extending ice depth measurements to lower frequencies, and potentially providing a deeper view into the ice shells of jovian moons.

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

    NASA Technical Reports Server (NTRS)

    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. Jupiter Icy Moons Orbiter (JIMO): An Element of the Prometheus Program

    NASA Astrophysics Data System (ADS)

    2004-10-01

    The Prometheus Program s Jupiter Icy Moons Orbiter (JIMO) Project is developing a revolutionary nuclear electric propulsion space system that would return scientific data from the icy Galilean satellites, Callisto, Ganymede, and Europa. This space system could also be used for future solar system exploration missions. Several major achievements occurred during Fiscal Year 2004 (FY 04). These include the addition of Department of Energy Naval Reactors (DOENR) and Northrop Grumman Space Technology (NGST) to the JIMO team, completion of the Science Definition Team s final report, generation of the Government and industry team trade studies and conceptual designs, and numerous technology demonstrations. The sections that follow detail these accomplishments.

  9. Current Status of Japanese Participation to Jupiter Icy Moons Explorer "JUICE"

    NASA Astrophysics Data System (ADS)

    Saito, Y.; Sasaki, S.; Kimura, J.; Tohara, K.; Fujimoto, M.; Sekine, Y.

    2015-12-01

    JUICE is an ESA's L-class mission to Explore Jupiter Icy Moons. The science objectives of JUICE is to understand (1) emergence of habitable worlds around gas giants and (2) Jupiter system as an archetype for gas giants. JUICE was mission adopted in November 2014. JUICE will be launched by Arian-5. After 7.5 years of interplanetary transfer and Earth-Venus-Earth-Earth gravity assists JUICE will be inserted into an orbit around Jupiter in January 2030. JUICE will make observation of all the three Jupiter icy Moons that potentially have subsurface ocean under the icy crust. After inserted into Ganymede orbit in 2032, JUICE will make detailed observation of the largest Icy Moon in the solar system. Three Japanese groups were selected to provide part of the three science instruments RPWI, GALA, and PEP/JNA. Two Japanese groups were also selected as science Co-I of two instrument groups JANUS and J-MAG. JUICE is the first mission for ISAS/JAXA to participate to foreign large science mission as a junior partner who will provide part of the science instruments. Taking into account all the data to be obtained by 5 instruments that JUICE-JAPAN will participate, Japanese team will be able to contribute to most of the major science objectives relating with planet Jupiter (JANUS), Jupiter magnetosphere (PEP/JNA, RPWI, and J-MAG), and Icy Moons (GALA, J-MAG, and JANUS). JUICE-JAPAN Working Group (WG) was established in September 2013. JUICE-JAPAN WG submitted a proposal for ISAS/JAXA small project in February 2014. JUICE-JAPAN WG passed the MDR in September 2014. JUICE-JAPAN passed the ISAS SRR that was held in April 2015 and also passed the ISAS project preparation review that was held in May 2015. Currently JUICE-JAPAN is an ISAS pre-project. In the future, SDR is scheduled in the end of 2015, PDR is scheduled in 2016 and CDR is scheduled in 2017. JUICE is a long-term mission that will be completed about 20 years from now. It is quite important to take place a necessary change

  10. Cosmic ion bombardment of the icy moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Strazzulla, G.

    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+, C+, N+, O+ and S+) 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 (CO2, SO2, H2SO4, 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 CO2 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 (H2CO3, and O-H in poly-water).Implantation of protons into sulfur dioxide produces SO3, polymers, and O3 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 CO2. 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 SO2 or H2S irradiation. No evidence for an efficient synthesis of SO2 has been found.

  11. JUICE: A European mission to Jupiter and its icy moons (Invited)

    NASA Astrophysics Data System (ADS)

    Dougherty, M. K.

    2013-12-01

    The recently selected European Space Agency mission JUICE (JUipter ICy moon Explorer), is planned for launch in 2022. Details of the mission will be described, including the payload, planned orbits and the resulting science. The focus of JUICE is to characterise the conditions that may have led to the emergence of habitable environments among the Jovian icy satellites, with special emphasis on the three ocean-bearing worlds, Ganymede, Europa, and Callisto. Ganymede is identified for detailed investigation since it provides a natural laboratory for analysis of the nature, evolution and potential habitability of icy worlds in general, but also because of the role it plays within the system of Galilean satellites, and its unique magnetic and plasma interactions with the surrounding Jovian environment. The mission will also focus on characterising the diversity of processes in the Jupiter system which may be required in order to provide a stable environment at Ganymede, Europa and Callisto on geologic time scales. Focused studies of Jupiter's atmosphere, and magnetosphere and their interaction with the Galilean satellites will further enhance our understanding of the evolution and dynamics of the Jovian system. JUICE spacecraft at Ganymede (courtesy Mike Carroll)

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Analysis of Thrust Vectoring Capabilities for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Quadrelli, Marco B .; Gromov, Konstantin; Murray, Emmanuell

    2005-01-01

    A strategy to mitigate the impact of the trajectory design of the Jupiter Icy Moons Orbiter (JIMO) on the attitude control design is described in this paper. This paper shows how the thrust vectoring control torques, i.e. the torques required to steer the vehicle, depend on various parameters (thrust magnitude, thrust pod articulation angles, and thrust moment arms). Rather than using the entire reaction control system (RCS) system to steer the spacecraft, we investigate the potential utilization of only thrust vectoring of the main ion engines for the required attitude control to follow the representative trajectory. This study has identified some segments of the representative trajectory where the required control torque may exceed the designed ion engine capability, and how the proposed mitigation strategy succeeds in reducing the attitude control torques to within the existing capability.

  14. High-Power Radar Sounders for the Investigation of Jupiter Icy Moons

    NASA Technical Reports Server (NTRS)

    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

  15. High-Power Radar Sounders for the Investigation of Jupiter Icy Moons

    NASA Technical Reports Server (NTRS)

    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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    measured throughout the jovian magnetosphere and in the local moon environments can act as tracers if we know from direct measurements and models the distributions at the mostly likely sources, i.e. at IO. However, our knowledge of these abundances are very limited from earlier in-situ and remote measurements, mainly confined to major (S, O) and some minor (Na, K, Cl) species with abundances at or above a few percent relative to O. Future in-situ plasma measurements by the planned Jupiter Europa Orbiter and Jupiter Ganymede Orbiter missions should extend the abundance coverage to minor and even trace elemental species. For Europa astrobiological investigations it is also important to specify iogenic inputs and surface processing of isotopic species. We discuss the range of abundance distributions arising from models for IO hot volcanic emissions, and from the subsequent dynamics of ion injection, magnetospheric transport, and icy moon surface bombardment.

  17. Moons around Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet; the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere.

    Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles); Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon; Ganymede is larger than the planet Mercury.

  18. Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    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

  19. Feasibility Study of a Nuclear-Stirling Power Plant for the Jupiter Icy Moons Orbiter

    NASA Astrophysics Data System (ADS)

    Schmitz, Paul C.; Schreiber, Jeffrey G.; Penswick, L. Barry

    2005-02-01

    NASA is undertaking the design of a new spacecraft to explore the planet Jupiter and its three moons Calisto, Ganymede and Europa. This proposed mission, known as Jupiter Icy Moons Orbiter (JIMO) would use a nuclear reactor and an associated electrical generation system (Reactor Power Plant - RPP) to provide power to the spacecraft. The JIMO spacecraft is envisioned to use this power for science and communications as well as Electric Propulsion (EP). Among other potential power-generating concepts, previous studies have considered Thermoelectric and Brayton power conversion systems, coupled to a liquid metal reactor for the JIMO mission. This paper will explore trades in system mass and radiator area for a nuclear reactor power conversion system, however this study will focus on Stirling power conversion. Stirling convertors have a long heritage operating in both power generation and the cooler industry, and are currently in use in a wide variety of applications. The Stirling convertor modeled in this study is based upon the Component Test Power Convertor design that was designed and operated successfully under the Civil Space Technology Initiative for use with the SP-100 nuclear reactor in the 1980's and early 1990's. The baseline RPP considered in this study consists of four dual-opposed Stirling convertors connected to the reactor by a liquid lithium loop. The study design is such that two of the four convertors would operate at any time to generate the 100 kWe while the others are held in reserve. For this study the Stirling convertors hot-side temperature is 1050 K, would operate at a temperature ratio of 2.4 for a minimum mass system and would have a system efficiency of 29%. The Stirling convertor would generate high voltage (400 volt), 100 Hz single phase AC that is supplied to the Power Management and Distribution system. The waste heat is removed from the Stirling convertors by a flowing liquid sodium-potassium eutectic and then rejected by a shared

  20. Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    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. Feasibility Study of a Nuclear-Stirling Plant for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Schreiber, Jeffrey G.; Penswick, L. Barry

    2005-01-01

    NASA is undertaking the design of a new spacecraft to explore the planet Jupiter and its three moons Calisto, Ganymede and Europa. This proposed mission, known as Jupiter Icy Moons Orbiter (JIMO) would use a nuclear reactor and an associated electrical generation system (Reactor Power Plant-RPP) to provide power to the spacecraft. The JIMO spacecraft is envisioned to use this power for science and communications as well as Electric Propulsion (EP). Among other potential power-generating concepts, previous studies have considered Thermoelectric and Brayton Power conversion systems, coupled to a liquid metal reactor for the JIMO mission. This paper will explore trades in system mass and radiator area for a nuclear reactor power conversion system, however this study will focus on Stirling power conversion. The Stirling convertor modeled in this study is based upon the Component Test Power Convertor design that was designed and operated successfully under the Civil Space Technology Initiative for use with the SP-100 nuclear reactor i the 1980's and early 1990's. The study design is such that two of the four convertors would operate at any time to generate the 100 kWe while the others are held in reserve. For this study the Stirling convertors hot-side temperature is 1050 K, would operate at a temperature ratio of 2.4 for a minimum mass system and would have a system efficiency of 29%. The Stirling convertor would generate high voltage (400 volt), 100 Hz single phase AC that is supplied to the Power Management and Distribution system. The waste hear is removed from the Stirling convertors by a flowing liquid sodium-potassium eutectic and then rejected by a shared radiator. The radiator consists of two coplanar wings, which would be deployed after the reactor is in space. System trades were performed to vary cycle state point temperatures and convertor design as well as power output. Other redundancy combinations were considered to understand the affects of convertor

  2. Theoretical studies of the radar properties of the icy Galilean moons of Jupiter

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1993-01-01

    The icy Galilean satellites of Jupiter - Europa, Ganymede, and Callisto - have unusual radar scattering properties compared with those of the terrestrial planets or Earth's Moon. There are three main features of the data that distinguish these targets: (1) the radar cross-section normalized by the geometrical cross-section is an order of magnitude larger than that of any terrestrial planet; (2) the reflected power is almost evenly distributed between two orthogonal polarizations with more power being returned in the same circular polarization as was transmitted whereas virtually all of the power returned from the terrestrial planets is contained in the opposite circular polarization to the one that was transmitted; and (3) the echo power spectra have a broad shape indicating a nearly uniformly radar-bright surface in contrast to the spectra from the terrestrial planets that contain a strong quasi-specular component from the vicinity of the sub-radar point and very little reflected power from the rest of the surface. The normalized radar cross-sections decrease as the areal water ice coverage decreases from Europa to Ganymede to Callisto. Recently, radar echoes from the polar caps of Mars and Mercury, and from Saturn's satellite Titan imply similarly strong cross-sections and have classically unexpected polarization properties and it is also thought that this is due to the presence of ice on the surface. A model called the radar glory model is analyzed and it is shown that the main features of the radar echoes calculated from this model agree well with the observations from all three icy Galilean satellites. This model involves long radar paths in the ice below the surface and special structures in which the refractive index decreases abruptly at a hemispherical boundary. It is not known whether such structures exist or how they could be created, but possible scenarios can be imagined such as the formation of an impact crater followed by deposition of a frost layer

  3. Status of the Ganymede Laser Altimeter (GALA) for ESA's Jupiter Icy Moons Explorer (JUICE)

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Exploring Jupiter's icy moons with old techniques and big facilities - new insights on sulfuric acid hydrates

    NASA Astrophysics Data System (ADS)

    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

  7. Decimeter-Wavelength Polarimetric Radar Imaging of the Icy Moons of Jupiter

    NASA Technical Reports Server (NTRS)

    Rosen, P. A.; Gurrola, E. M.; Madsen, S. N.

    2003-01-01

    Imaging radars with wavelengths in the range of 10 cm to 1 m can deeply penetrate the surface of an icy body, revealing details of the geomorphology, local structure, and electrical properties of the upper layers. Radar studies of icy surfaces on Earth have used the polarization state of backscatter echoes at multiple frequencies to characterize the surface and subsurface properties of glaciers, showing relatively smooth surfaces on the scale of radar wave-lengths, and subsurface scattering from volume scatterers consistent with ice pipes and lenses. These volume scattering effects are evident in enhanced polarization ratios over a limited range of backscatter incidence angles. The Galilean satellites exhibit similarly enhanced polarization ratios and volumetric scattering effects, but the observations are limited in angular resolution, leading to ambiguity in interpreting the scattering mechanisms and their structural implications.

  8. Environmental Change in Icy Moons

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Vance, S.

    2014-12-01

    There is strong evidence that subsurface oceans could exist within several of the outer solar system's ice-rich moons, at Jupiter (Europa, Ganymede, and Callisto), Saturn (Enceladus and Titan), and Neptune (Triton). If liquid water is indeed available in these subsurface environments, then the availability of chemical energy becomes the greatest limitation on whether icy worlds could harbor life. Of these moons, the largest (Ganymede, Callisto, and Titan) are expected to harbor oceans deep within, and high-pressure H2O ice phases are expected farther beneath those deep oceans. In contrast, the oceans of smaller icy worlds—Europa, Enceladus, and Triton—are plausibly in direct contact with rock below. Given that serpentinization or other water-rock geochemical activity could supply reductants directly to their oceans, these icy worlds have the greatest chance to support present-day microbial life. Each of these three icy worlds displays spectacular resurfaced terrains that are very young (crater retention ages ~10s Myr and younger), with their internal activity linked to extremes in tidal heating today and/or in the geologically recent past. However, the degree of their tidal heating may have changed greatly over time. Europa is believed to experience cyclical tidal heating and activity; Enceladus may have experienced cyclical activity or a geologically recent pulse of activity; Triton may have experienced extreme tidal heating upon its capture and orbital circularization. Such dynamic pasts would pose challenges for any life within. We consider the possible effects of severe swings in the activity level of icy worlds, specifically the implications for delivery of chemical energy to their subsurface oceans.

  9. Jupiter's Moons: Family Portrait

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This montage shows the best views of Jupiter's four large and diverse 'Galilean' satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter.

    Io, 3,640 kilometers (2,260 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.7 million kilometers (1.7 million miles). The original image scale was 13 kilometers per pixel, and the image is centered at Io coordinates 6 degrees south, 22 degrees west. Io is notable for its active volcanism, which New Horizons has studied extensively.

    Europa, 3,120 kilometers (1,938 miles) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 3 million kilometers (1.8 million miles). The original image scale was 15 kilometers per pixel, and the image is centered at Europa coordinates 6 degrees south, 347 degrees west. Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa's surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it.

    New Horizons spied Ganymede, 5,262 kilometers (3,268 miles) in diameter, at 10:01 Universal Time on February 27 from 3.5 million kilometers (2.2 million miles) away. The original scale was 17 kilometers per pixel, and the image is centered at Ganymede coordinates 6 degrees south, 38 degrees west. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior.

    Callisto, 4,820 kilometers (2,995 miles) in diameter, was imaged

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Traveling Wave Tube (TVT) RF Power Combining Demonstration for use in the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    Downey, Joseph A.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is set to launch between the years 2012 and 2015. It will possibly utilize a nuclear reactor power source and ion engines as it travels to the moons of Jupiter. The nuclear reactor will produce hundreds of kilowatts of power for propulsion, communication and various scientific instruments. Hence, the RF amplification devices aboard will be able to operate at a higher power level and data rate. The initial plan for the communications system is for an output of 1000 watts of RF power, a data rate of at least 10 megabits a second, and a frequency of 32 GHz. A higher data rate would be ideal to fully utilize the instruments aboard JIMO. At NASA Glenn, one of our roles in the JIMO project is to demonstrate RF power combining using multiple traveling wave tubes (TWT). In order for the power of separate TWT s to be combined, the RF output waves from each must be in-phase and have the same amplitude. Since different tubes act differently, we had to characterize each tube using a Network Analyzer. We took frequency sweeps and power sweeps to characterize each tube to ensure that they will behave similarly under the same conditions. The 200 watt Dornier tubes had been optimized to run at a lower power level (120 watts) for their extensive use in the ACTS program, so we also had to experiment with adjusting the voltage settings on several internal components (helix, anode, collector) of the tubes to reach the full 200 watt potential. from the ACTS program. Phase shifters and power attenuators were placed in the waveguide circuit at the inputs to the tubes so that adjustments could be made individually to match them exactly. A magic tee was used to route and combine the amplified electromagnetic RF waves on the tube output side. The demonstration of 200 watts of combined power was successful with efficiencies greater than 90% over a 500 MHz bandwidth. The next step will be to demonstrate the use of three amplifiers using two magic tees by

  13. Traveling Wave Tube (TVT) RF Power Combining Demonstration for use in the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    Downey, Joseph A.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is set to launch between the years 2012 and 2015. It will possibly utilize a nuclear reactor power source and ion engines as it travels to the moons of Jupiter. The nuclear reactor will produce hundreds of kilowatts of power for propulsion, communication and various scientific instruments. Hence, the RF amplification devices aboard will be able to operate at a higher power level and data rate. The initial plan for the communications system is for an output of 1000 watts of RF power, a data rate of at least 10 megabits a second, and a frequency of 32 GHz. A higher data rate would be ideal to fully utilize the instruments aboard JIMO. At NASA Glenn, one of our roles in the JIMO project is to demonstrate RF power combining using multiple traveling wave tubes (TWT). In order for the power of separate TWT s to be combined, the RF output waves from each must be in-phase and have the same amplitude. Since different tubes act differently, we had to characterize each tube using a Network Analyzer. We took frequency sweeps and power sweeps to characterize each tube to ensure that they will behave similarly under the same conditions. The 200 watt Dornier tubes had been optimized to run at a lower power level (120 watts) for their extensive use in the ACTS program, so we also had to experiment with adjusting the voltage settings on several internal components (helix, anode, collector) of the tubes to reach the full 200 watt potential. from the ACTS program. Phase shifters and power attenuators were placed in the waveguide circuit at the inputs to the tubes so that adjustments could be made individually to match them exactly. A magic tee was used to route and combine the amplified electromagnetic RF waves on the tube output side. The demonstration of 200 watts of combined power was successful with efficiencies greater than 90% over a 500 MHz bandwidth. The next step will be to demonstrate the use of three amplifiers using two magic tees by

  14. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the opposition surge of the icy Europa

    NASA Astrophysics Data System (ADS)

    Molaro, P.; Barbieri, M.; Monaco, L.; Zaggia, S.; Lovis, C.

    2015-10-01

    We report on a multiwavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 2014 January 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with high accuracy radial velocity planetary searcher (HARPS) from La Silla, Chile and HARPS-N from La Palma, Canary Islands were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit. The expected modulation in radial velocities was of ≈20 cm s-1 but an anomalous drift as large as ≈38 m s-1, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and Birmingham Solar Oscillations Network observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the opposition surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion of the solar surface centred around the crossing Earth which can then be observed as a sort of inverse Rossiter-McLaughlin effect. in fact, a simplified model of this effect can explain in detail most features of the observed radial velocity anomalies, namely the extensions before and after the transit, the small differences between the two observatories and the presence of a secondary peak closer to Earth passage. This phenomenon, observed here for the first time, should be observed every time similar Earth alignments occur with rocky bodies without atmospheres. We predict that it should be observed again during the next conjunction of Earth and Jupiter in 2026.

  15. Jupiter's Hot, Mushy Moon

    NASA Technical Reports Server (NTRS)

    Taylor, G. Jeffrey

    2003-01-01

    Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Jupiter's moon Io

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This picture shows a special color reconstruction of one of the erupting volcanos on Io discovered by Voyager 1 during its encounter with Jupiter on the 4th and 5th of March. The picture was taken March 4 about 5:00 p.m. from a range of about half a million kilometers showing an eruption region on the horizon. This method of color analysis allows scientists to combine data from four pictures, taken in ultraviolet, blue, green and orange light. In this picture one can see the strong change in color of the erupting plume. The region that is brighter in ultraviolet light (blue in this image) is much more extensive than the denser, bright yellow region near the center of the eruption. Scientists will use data of this type to study the amount of gas and dust in the eruption and the size of dust particles. Preliminary analysis suggests that the bright ultraviolet part of the cloud may be due to scattered light from very fine particles (the same effect which makes smoke appear bluish).

  18. Nano Icy Moons Propellant Harvester

    NASA Technical Reports Server (NTRS)

    VanWoerkom, Michael (Principal Investigator)

    2017-01-01

    As one of just a few bodies identified in the solar system with a liquid ocean, Europa has become a top priority in the search for life outside of Earth. However, cost estimates for exploring Europa have been prohibitively expensive, with estimates of a NASA Flagship class orbiter and lander approaching $5 billion. ExoTerra's NIMPH offers an affordable solution that can not only land, but return a sample from the surface to Earth. NIMPH combines solar electric propulsion (SEP) technologies being developed for the asteroid redirect mission and microsatellite electronics to reduce the cost of a full sample return mission below $500 million. A key to achieving this order-of-magnitude cost reduction is minimizing the initial mass of the system. The cost of any mission is directly proportional to its mass. By keeping the mission within the constraints of an Atlas V 551 launch vehicle versus an SLS, we can significantly reduce launch costs. To achieve this we reduce the landed mass of the sample return lander, which is the largest multiplier of mission mass, and shrink propellant mass through high efficiency SEP and gravity assists. The NIMPH projects first step in reducing landed mass focuses on development of a micro-In Situ Resource Utilization (micro-ISRU) system. ISRU allows us to minimize landed mass of a sample return mission by converting local ice into propellants. The project reduces the ISRU system to a CubeSat-scale package that weighs just 1.74 kg and consumes just 242 W of power. We estimate that use of this ISRU vs. an identical micro-lander without ISRU reduces fuel mass by 45 kg. As the dry mass of the lander grows for larger missions, these savings scale exponentially. Taking full advantage of the micro-ISRU system requires the development of a micro-liquid oxygen-liquid hydrogen engine. The micro-liquid oxygen-liquid hydrogen engine is tailored for the mission by scaling it to match the scale of the micro-lander and the low gravity of the target moon

  19. Two Moons Meet over Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This beautiful image of the crescents of volcanic Io and more sedate Europa was snapped by New Horizons' color Multispectral Visual Imaging Camera (MVIC) at 10:34 UT on March 2, 2007, about two days after New Horizons made its closest approach to Jupiter.

    The picture was one of a handful of the Jupiter system that New Horizons took primarily for their artistic, rather than scientific value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.

    This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. The night side of Io is illuminated here by light reflected from Jupiter, which is out of the frame to the right. Europa's night side is completely dark, in contrast to Io, because that side of Europa faces away from Jupiter.

    Here, Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) -high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are barely visible: one from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and one from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The plumes appear blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.

    The images are centered at 1 degree north, 60 degrees west on Io, and 0 degrees north, 149 degrees west on Europa. The color in this

  20. Two Moons Meet over Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This beautiful image of the crescents of volcanic Io and more sedate Europa was snapped by New Horizons' color Multispectral Visual Imaging Camera (MVIC) at 10:34 UT on March 2, 2007, about two days after New Horizons made its closest approach to Jupiter.

    The picture was one of a handful of the Jupiter system that New Horizons took primarily for their artistic, rather than scientific value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.

    This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. The night side of Io is illuminated here by light reflected from Jupiter, which is out of the frame to the right. Europa's night side is completely dark, in contrast to Io, because that side of Europa faces away from Jupiter.

    Here, Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) -high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are barely visible: one from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and one from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The plumes appear blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.

    The images are centered at 1 degree north, 60 degrees west on Io, and 0 degrees north, 149 degrees west on Europa. The color in this

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Surfaces and exospheres of the icy Galilean moons - an integral approach

    NASA Astrophysics Data System (ADS)

    Galli, André; Wurz, Peter; Vorburger, Audrey; Tulej, Marek; Pommerol, Antoine; Scheer, Jürgen; Thomas, Nicolas; Mousis, Olivier; Barabash, Stas; Wieser, Martin; Lammer, Helmut

    2014-05-01

    The JUpiter ICy moons Explorer (JUICE) will investigate Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. Europa and Callisto flybys will allow for a comparative picture of the icy Galilean moons. As part of the scientific preparation work for JUICE, we examine the requirements and expected science results related to the Neutral gas and Ion Mass spectrometer (NIM), which belongs to the Particle Environment Package on board JUICE. Models of the exosphere profiles at Europa, Ganymede, and Callisto allow us to optimize the design of NIM, but the reliability of the models is limited because the properties of icy surfaces, in particular sputtering and sublimation parameters for icy regolith mixed with carbonates or salts, are not well known. We therefore have started a series of lab experiments with icy regolith subjected to ion and UV irradiation in a cold vacuum. Currently, we perform irradiation experiments of pure water ice with H+ and O+ ions. In the coming years, we will expand the experiments to more complex cases (including UV-radiation, temperature cycles and chemical impurities such as O2, C, S, CO2, SO2, and Na) relevant for Galilean moons. The results will constrain exosphere models and will enable the scientific community to better link exosphere measurements with processes in the ice and observed surface features.

  4. Radiation Synthesis of New Molecules on Jupiter's Icy Satellites

    NASA Technical Reports Server (NTRS)

    Moore, M. H.; Hudson, R. L.; Carlson, R. W.

    2003-01-01

    Spectra of Jupiter's icy satellites reveal surfaces dominated by water-ice, minor amounts of SO2 and CO2, and (for Europa) H2O2 along with hydrated materials. Jovian magnetospheric ions (protons, sulfur, and oxygen) and electrons significantly modify the chemical composition of these moons' surfaces in times ranging from a few years for Europa to thousands of years for Callisto at micrometer depths. Appropriate laboratory studies examining relevant volatile and non-volatile materials under low-temperature radiation conditions can provide information on likely radiation chemical mechanisms, on the stability and evolution of species, and on new species awaiting detection. Although the molecules detected on the icy moons are relatively simple, predicting their responses to radiation in space remains difficult. One problem is that there is a dearth of fundamental data examining solid-phase reactions. Our laboratory experiments have focused on infrared studies (2.5 to 25 microns) of a few simple irradiated ices. We have measured the spectra of proton-irradiated H2O ice containing SO2, H2S, and/or CO2. Ices with H2O/SO2 or H2O/H2S ratios of 3 and 30 have been irradiated at 86 K, 110 K, and 132 K. In irradiated H2O + SO2 ices new ions have been identified: SO4(-2), HSO4(-) and H3O(+). After warming to 260 K the residual spectrum is similar to that of H2SO4. Ices with H2O + H2S form SO2. After warming to 175 K, the residual sample matches the spectrum of hydrated H2SO4. H2O + CO2 ice forms carbonic acid, H2CO3 which is stable to temperatures near 230 K. In addition, OCS has been detected in irradiated ices containing H2O + SO2 + CO2. The radiation half-life of SO2 and H2S in H2O has been calculated. Our results give compelling evidence for the presence of new species awaiting detection. Future experiments will examine the signatures of these ices and hydrated materials in the 1 to 5 micron region, where possible weaker overtone bands may occur. In addition, absolute

  5. Radiation Synthesis of New Molecules on Jupiter's Icy Satellites

    NASA Technical Reports Server (NTRS)

    Moore, M. H.; Hudson, R. L.; Carlson, R. W.

    2003-01-01

    Spectra of Jupiter's icy satellites reveal surfaces dominated by water-ice, minor amounts of SO2 and CO2, and (for Europa) H2O2 along with hydrated materials. Jovian magnetospheric ions (protons, sulfur, and oxygen) and electrons significantly modify the chemical composition of these moons' surfaces in times ranging from a few years for Europa to thousands of years for Callisto at micrometer depths. Appropriate laboratory studies examining relevant volatile and non-volatile materials under low-temperature radiation conditions can provide information on likely radiation chemical mechanisms, on the stability and evolution of species, and on new species awaiting detection. Although the molecules detected on the icy moons are relatively simple, predicting their responses to radiation in space remains difficult. One problem is that there is a dearth of fundamental data examining solid-phase reactions. Our laboratory experiments have focused on infrared studies (2.5 to 25 microns) of a few simple irradiated ices. We have measured the spectra of proton-irradiated H2O ice containing SO2, H2S, and/or CO2. Ices with H2O/SO2 or H2O/H2S ratios of 3 and 30 have been irradiated at 86 K, 110 K, and 132 K. In irradiated H2O + SO2 ices new ions have been identified: SO4(-2), HSO4(-) and H3O(+). After warming to 260 K the residual spectrum is similar to that of H2SO4. Ices with H2O + H2S form SO2. After warming to 175 K, the residual sample matches the spectrum of hydrated H2SO4. H2O + CO2 ice forms carbonic acid, H2CO3 which is stable to temperatures near 230 K. In addition, OCS has been detected in irradiated ices containing H2O + SO2 + CO2. The radiation half-life of SO2 and H2S in H2O has been calculated. Our results give compelling evidence for the presence of new species awaiting detection. Future experiments will examine the signatures of these ices and hydrated materials in the 1 to 5 micron region, where possible weaker overtone bands may occur. In addition, absolute

  6. Geologic Evolution of Saturn's Icy Moon Tethys

    NASA Astrophysics Data System (ADS)

    Wagner, Roland; Stephan, K.; Schmedemann, N.; Roatsch, T.; Kersten, E.; Neukum, G.; Porco, C. C.

    2013-10-01

    Tethys, 1072 km in diameter, is a mid-sized icy moon of Saturn imaged for the first time in two Voyager flybys [1][2][3]. Since July 2004, its surface has been imaged by the Cassini ISS cameras at resolutions between 200 and 500 m/pxl. We present results from our ongoing work to define and map geologic units in camera images obtained preferentially during Cassini’s Equinox and Solstice mission phases. In the majority of Tethys’ surface area a densely cratered plains unit [1][2][3][this work] is abundant. The prominent graben system of Ithaca Chasma is mapped as fractured cratered plains. Impact crater and basin materials can be subdivided into three degradational classes. Odysseus is a fresh large impact basin younger than Ithaca Chasma according to crater counts [4]. Heavily degraded craters and basins occur in the densely cratered plains unit. A smooth, less densely cratered plains unit in the trailing hemisphere was previously identified by [2] but mapping of its boundaries is difficult due to varying viewing geometries of ISS images. To the south of Odysseus, we identified a cratered plains unit not seen in Voyager data, characterized by remnants of highly degraded large craters superimposed by younger fresher craters with a lower crater density compared to the densely cratered plains unit. Its distinct linear northern contact with the densely cratered plains suggests a tectonic origin. Sets of minor fractures can be distinguished in the densely cratered plains, and locally, features of mass wasting can be observed. References: [1] Smith B. A. et al. (1981), Science 212, 163-191. [2] Smith B. A. et al. (1982), Science 215, 504-537. [3] Moore J. M. and Ahern J. L. (1983), JGR 88 (suppl.), A577-A584. [4] Giese B. et al. (2007), GRL 34, doi:10.1029/2007GL031467.

  7. Exchange processes from the deep interior to the surface of icy moons

    NASA Astrophysics Data System (ADS)

    Grasset, O.

    Space exploration provides outstanding images of planetary surfaces. Galileo space- craft around Jupiter, and now Cassini in the saturnian system have revealed to us the variety of icy surfaces in the solar system. While Europa, Enceladus, and maybe Titan present past or even active tectonic and volcanic activities, many other moons have been dead worlds for more than 3 billions years. Composition of ices is also complex and it is now commonly admitted that icy surfaces are never composed of pure ices. Water ice can be mixed with salts (Europa?), with hydrocarbons (Titan?) or with silicates (Callisto). The present surfaces of icy moons are the results of both internal (tectonic; volcanism; mantle composition; magnetic field; . . . ) and external processes (radiations, atmospheres, impacts, . . . ). Internal activity (past or present) is almost unknown. While the surfaces indicate clearly that an important activity existed (Ganymede, Europa, Titan, . . . ) or still exists (Enceladus, Titan?, . . . ), volcanic and tectonic processes within icy mantles are still very poorly understood. This project proposes some key studies for improving our knowledge of exchange processes within icy moons, which are: 1) Surface compositions: Interpretation of mapping spectrometer data. It addresses the interpretation of remote sensing data. These data are difficult to understand and a debate between people involved in Galileo and those who are now trying to interpret Cassini data might be fruitful. As an example, interpretation of Galileo data on Europa are still controversial. It is impossible to affirm that the "non-icy" material which does not present the classic infrared signature of pure ice is due to the presence of magnesium hydrates, sodium hydrates, magnesium sulfurs, "clays", or even altered water ice. Discussion on the subject are still needed. On Titan, the presence of the atmosphere impedes to link IR data from Cassini to the composition of the surface. 2) Past and

  8. Habitability potential of icy moons: a comparative study

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    environments to look for biomarkers. Currently, for Titan and Enceladus, geophysical models try to explain the possible existence of an oceanic layer that decouples the mantle from the icy crust. If the silicate mantles of Eu-ropa and Ganymede and the liquid sources of Titan and Enceladus are geologically active as on Earth, giving rise to the equivalent of hydrothermal systems, the simultaneous presence of water, geodynamic interactions, chemical en-ergy sources and a diversity of key chemical elements may fulfill the basic conditions for habitability. Titan has been suggested to be a possible cryovolcanic world due to the presence of local complex volcanic-like geomorphol-ogy and the indications of surface albedo changes with time [7,8]. Such dynamic activity that would most probably include tidal heating, possible internal convection, and ice tectonics, is believed to be a pre-requisite of a habitable planetary body as it allows the recycling of minerals and potential nutrients and provides localized energy sources. In a recent study by Sohl et al. [2013], we have shown that tidal forces are a constant and significant source of inter-nal deformation on Titan and the interior liquid water ocean can be relatively warm for reasonable amounts of am-monia concentrations, thus completing the set of parameters needed for a truly habitable planetary body. Such habi-tability indications from bodies at distances of 10 AU, are essential discoveries brought to us by space exploration and which have recently revolutionized our perception of habitability in the solar system. In the solar system's neighborhood, such potential habitats can only be investigated with appropriate designed space missions, like JUICE-Laplace (JUpiter ICy moon Explorer) for Ganymede and Europa [9]. JUICE is an ESA mission to Jupiter and its icy moons, recently selected to launch in 2022. References: [1] Coustenis, A., Encrenaz, Th., in "Life Beyond Earth : the search for habitable worlds in the Universe

  9. Spectroscopy of Icy Moon Surface Materials

    NASA Astrophysics Data System (ADS)

    Dalton, J. B.

    2010-06-01

    Remote sensing of icy objects in the outer solar system relies upon availability of appropriate laboratory measurements. Surface deposits of specific substances often provide our most direct route to understanding interior composition, thereby informing theories of endogenic surface modification, exogenic surface processing and processes involving exchange of material with the interiors. Visible to near-infrared reflectance spectra of properly prepared compounds are required to enable retrieval of surface abundances through linear and nonlinear mixture analysis applied to spacecraft observations of icy bodies. This chapter describes the techniques, conditions and approaches necessary to provide reference spectra of use to theoretical models of icy satellite surface compositions, and summarizes the current state of knowledge represented in the published literature.

  10. Surface Irradiation of Jupiter's Moon Europa

    NASA Astrophysics Data System (ADS)

    Rubin, M.; Tenishev, V.; Combi, M. R.; Jia, X.; Hansen, K. C.; Gombosi, T. I.

    2010-12-01

    Jupiter’s moon Europa has a complex and tightly coupled interaction with the Jovian magnetosphere. Neutral gas of the moon’s exosphere is ionized and picked up by the corotating plasma that sweeps past Europa at a relative velocity of almost 100 km/s. This pick-up process alters the magnetic and electric field topology around Europa, which in turn affects the trajectories of the pick-up ions as well as the thermal and hot magnetospheric ions that hit the moon’s icy surface. In turn these surface-impinging ions are the responsible source for the sputtered neutral atmosphere, which itself is again crucial for the exospheric mass loading of the surrounding plasma. We use the magnetohydrodynamics (MHD) model BATSRUS to model the interaction of Europa with the Jovian magnetosphere. The model accounts for the exospheric mass loading, ion-neutral charge exchange, and ion-electron recombination [Kabin et al. (J. Geophys. Res., 104, A9, 19,983-19,992, 1999)]. The derived magnetic and electric fields are then used in our Test Particle Monte Carlo (TPMC) model to integrate individual particle trajectories under the influence of the Lorentz force. We take the measurements performed by Galileo’s Energetic Particle Detector (EPD) [Williams et al. (Sp. Sci. Rev. 60, 385-412, 1992) and Cooper et al. (Icarus 149, 133-159, 2001)] and the Plasma Analyzer (PLS) [Paterson et al. (J. Geophys. Res., 104, A10, 22,779-22,791, 1999)] as boundary conditions. Using a Monte Carlo technique allows to individually track ions in a wide energy range and to individually calculate their energy deposition on the moon’s surface. The sputtering yield is a function of incident particle type, energy, and mass. We use the measurements performed by Shi et al. (J. Geophys. Res., 100, E12, 26,387-26,395, 1995) to turn the modeled impinging ion flux into a neutral gas production rate at the surface. We will show preliminary results of this work with application to the missions to the Jupiter system

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

    NASA Astrophysics Data System (ADS)

    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

  12. Himalia, a Small Moon of Jupiter

    NASA Technical Reports Server (NTRS)

    2001-01-01

    NASA's Cassini spacecraft captured images of Himalia, the brightest of Jupiter's outer moons, on Dec. 19, 2000, from a distance of 4.4 million kilometers (2.7 million miles).

    This near-infrared image, with a resolution of about 27 kilometers (17 miles) per pixel, indicates that the side of Himalia facing the spacecraft is roughly 160 kilometers (100 miles) in the up-down direction. Himalia probably has a non-spherical shape. Scientists believe it is a body captured into orbit around Jupiter, most likely an irregularly shaped asteroid.

    In the main frame, an arrow indicates Himalia. North is up. The inset shows the little moon magnified by a factor of 10, plus a graphic indicating Himalia's size and the direction of lighting (with sunlight coming from the left). Cassini's pictures of Himalia were taken during a brief period when Cassini's attitude was stabilized by thrusters instead of by a steadier reaction-wheel system. No spacecraft or telescope had previously shown any of Jupiter's outer moons as more than a star-like single dot.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  13. Inverse theory resolution analysis in planning radio science gravity investigations of icy moons

    NASA Astrophysics Data System (ADS)

    Ganse, A.; Vance, S.

    2014-12-01

    The nature of an icy satellite's interior relates fundamentally to its composition, thermal structure, formation and evolution history, and prospects for supporting life. Gravity measurements via radio Doppler information during spacecraft flybys constitute an important tool to infer gross interior structure. Liquid water and ice layers have previously been inferred for the interiors of Jupiter's icy satellites Europa, Ganymede, and Callisto on the basis of magnetic field measurements by the Galileo probe. On Europa and Callisto induced magnetic field signatures measured by the Galileo probe provided strong evidence for an ionic aqueous ocean. Among the chief goals of the proposed Europa Clipper mission in returning to Europa is characterizing the structure of the moon's icy shell. A geophysical inverse theory resolution analysis can be calculated at the pre-measurement mission planning stage, contributing planning considerations from the point of view of the search for mass anomalies in the ice shell (meteorites or diapiric upwellings) or near the H2O/rock interface (seamounts). The analysis allows us to assess the location-varying resolution of an icy moon's interior density anomaly distribution that can be estimated from radio Doppler measurements. It considers the tradeoff between the resolution of the estimated density anomaly distribution and its estimation uncertainty, and investigates issues in distinguishing between ocean anomalies (e.g., seamounts) and mass anomalies within or near the surface of the ice layer. We apply the resolution analysis to proposed Europa Clipper trajectories and past Galileo spacecraft trajectories about Europa and Ganymede.

  14. Crustal failure on icy Moons from a strong tidal encounter

    NASA Astrophysics Data System (ADS)

    Quillen, Alice C.; Giannella, David; Shaw, John G.; Ebinger, Cynthia

    2016-09-01

    Close tidal encounters among large planetesimals and Moons should have been more common than grazing or normal impacts. Using a mass spring model within an N-body simulation, we simulate the deformation of the surface of an elastic spherical body caused by a close parabolic tidal encounter with a body that has similar mass as that of the primary body. Such an encounter can induce sufficient stress on the surface to cause brittle failure of an icy crust and simulated fractures can extend a large fraction of the radius of body. Strong tidal encounters may be responsible for the formation of long graben complexes and chasmata in ancient terrain of icy Moons such as Dione, Tethys, Ariel and Charon.

  15. ESO Observations of New Moon of Jupiter

    NASA Astrophysics Data System (ADS)

    2000-08-01

    Two astronomers, both specialists in minor bodies in the solar system, have performed observations with ESO telescopes that provide important information about a small moon, recently discovered in orbit around the solar system's largest planet, Jupiter. Brett Gladman (of the Centre National de la Recherche Scientifique (CNRS) and working at Observatoire de la Cote d'Azur, France) and Hermann Boehnhardt ( ESO-Paranal) obtained detailed data on the object S/1999 J 1 , definitively confirming it as a natural satellite of Jupiter. Seventeen Jovian moons are now known. The S/1999 J 1 object On July 20, 2000, the Minor Planet Center (MPC) of the International Astronomical Union (IAU) announced on IAU Circular 7460 that orbital computations had shown a small moving object, first seen in the sky in 1999, to be a new candidate satellite of Jupiter. The conclusion was based on several positional observations of that object made in October and November 1999 with the Spacewatch Telescope of the University of Arizona (USA). In particular, the object's motion in the sky was compatible with that of an object in orbit around Jupiter. Following the official IAU procedure, the IAU Central Bureau for Astronomical Telegrams designated the new object as S/1999 J 1 (the 1st candidate Satellite of Jupiter to be discovered in 1999). Details about the exciting detective story of this object's discovery can be found in an MPC press release and the corresponding Spacewatch News Note. Unfortunately, Jupiter and S/1999 J 1 were on the opposite side of the Sun as seen from the Earth during the spring of 2000. The faint object remained lost in the glare of the Sun in this period and, as expected, a search in July 2000 through all available astronomical data archives confirmed that it had not been seen since November 1999, nor before that time. With time, the extrapolated sky position of S/1999 J 1 was getting progressively less accurate. New observations were thus urgently needed to "recover

  16. Compositional Remote Sensing of Icy Planets and Satellites Beyond Jupiter

    NASA Technical Reports Server (NTRS)

    Roush, T. L.

    2002-01-01

    The peak of the solar energy distribution occurs at visual wavelengths and falls off rapidly in the infrared. This fact, improvements in infrared detector technology, and the low surface temperatures for most icy objects in the outer solar system have resulted in the bulk of telescopic and spacecraft observations being performed at visual and near-infrared wavelengths. Such observations, begun in the early 1970's and continuing to present, have provided compositional information regarding the surfaces of the satellites of Saturn and Uranus, Neptune's moon Triton, Pluto, Pluto's moon Charon, Centaur objects, and Kuiper belt objects. Because the incident sunlight penetrates the surface and interacts with the materials present there, the measured reflected sunlight contains information regarding the surface materials, and the ratio of the reflected to incident sunlight provides a mechanism of identifying the materials that are present.

  17. Absorption of trapped particles by Jupiter's moons

    NASA Technical Reports Server (NTRS)

    Hess, W. N.; Birmingham, T. J.; Mead, G. D.

    1974-01-01

    Inclusion of absorption effects of the four innermost moons in the radial transport equations for electrons and protons in Jupiter's magnetosphere. It is found that the phase space density n at 2 Jupiter radii for electrons with equatorial pitch angles less than 69 deg is reduced by a factor of 42,000 when lunar absorption is included in the calculation. For protons with equatorial pitch angles less than 69 deg the corresponding reduction factor is 2,300,000. The effect of the satellites becomes progressively weaker for both electrons and protons as equatorial pitch angles of 90 deg are approached, because the likelihood of impacting a satellite becomes progressively smaller. The large density decreases found at the orbits of Io, Europa, and Ganymede result in corresponding particle flux decreases that should be observed by spacecraft making particle measurements in Jupiter's magnetosphere. The characteristic signature of satellite absorption should be a downward-pointing vertex in the flux versus radius curve at the L value corresponding to each satellite.

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

    NASA Technical Reports Server (NTRS)

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

    NASA Technical Reports Server (NTRS)

    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

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

    PubMed

    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.

  1. Positional Catalogues of Saturn's and Jupiter's Moons

    NASA Astrophysics Data System (ADS)

    Yizhakevych, O.; Andruk, V.; Pakuliak, L.; Lukianchuk, V.; Shatokhina, S.

    In the framework of the UkrVO national project (http://ukr-vo.org/) we have started the processing of photographic observations of Saturn's (S1-S8) and Jupiter's (J6-J8) moons. Observations were conducted during 1961-1993 with three astrographs DLFA, DWA, DAZ and Z600 reflector. Plate images were digitized as tif-files with commercial scanners. Image processing was carried out by specific software package in the LINUX-MIDAS-ROMAFOT environment with Tycho2 as reference. The software was developed at the MAO NASU. Obtained positions of objects were compared with theoretically predicted ones in IMCCE (Paris) (www.imcce.fr/sat) online. Rms error of divergence between observed and calculated positions is of 0.20' - 0.35'.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Absorption of trapped particles by Jupiter's moons

    NASA Technical Reports Server (NTRS)

    Hess, W. N.; Birmingham, T. J.; Mead, G. D.

    1973-01-01

    Absorption effects of the four innermost moons in the radial transport equations for electrons and protons in Jupiter's magnetosphere are presented. The phase space density n at 2 R sub J for electrons with equatorial pitch angles less than 69 deg is reduced by a factor of 4.2 x 1000 when lunar absorption is included in the calculation. For protons with equatorial pitch angles less than 69 deg, the corresponding reduction factor is 3.2 x 100000. The effect of the satellites becomes progressively weaker for both electrons and protons as equatorial pitch angles of pi/2 are approached, because the likelihood of impacting a satellite becomes progressively smaller. The large density decreases which we find at the orbits of Io, Europa, and Ganymede result in corresponding particle flux decreases that should be observed by spacecraft making particle measurements in Jupiter's magnetosphere. The characteristic signature of satellite absorption should be a downward pointing cusp in the flux versus radius curve at the L-value corresponding to each satellite.

  4. Habitability of the giant icy moons: current knowledge and future insights from the JUICE mission

    NASA Astrophysics Data System (ADS)

    Grasset, O.; Prieto-Ballesteros, O.; Titov, D.; Erd, C.; Bunce, E.; Coustenis, A.; Blanc, M.; Coates, A.; Fletcher, L.; van Hoolst, T.; Hussmann, H.; Jaumann, R.; Krupp, N.; Tortora, P.; Tosi, F.; Wielders, A.

    2012-09-01

    Large satellites of gas giants, at orbits beyond the snow-line, such as Jupiter or Saturn, can contain a large amount of water (almost 45% in mass). Hydrospheres are extremely thick, ~600 km for Ganymede and Callisto, and may possess liquid layers below the icy crust. Thus, the Galilean satellites provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the Voyager and Galileo spacecraft revealed the potential of these satellites in this context. The JUpiter Icy moons Explorer (JUICE) will greatly enhance our understanding of their potential habitability. It is known, even at Earth where life mostly depends on solar energy, that habitats exist deep in the oceans in eternal darkness feeding on chemical energy. Aqueous layers are suspected below the icy crusts of the moons, which possess similar physical characteristics than Earth's deep oceans. Since they are certainly very stable through time, and because complex chemistry and energy sources may be available, life may have originated within such subsurface habitats despite the hostile surface conditions. Liquid water reservoirs have been proposed on Ganymede, Europa and Callisto from geophysical models, based on Galileo observations. These oceans that are covered by ice shells exist independently of the input of stellar energy, and are located well outside the conventional habitable zone of the Sun. Considering the pressure range encountered within the icy moons, four different scenarios can be defined. These result from varying thicknesses of the water ice layers and the liquid ocean with respect to the silicate floor (Figure 1). Case 2 in Figure 1 is highly probable for the largest moons (Ganymede and Callisto), while case 3 is more probable for Europa and smaller icy moons if they host liquid reservoirs such as has been discovered at Enceladus. Europa's ocean is unique because it may be in contact with the rock layer. This substrate may be

  5. What Would Constitute Evidence for Life on Icy Moons?

    NASA Technical Reports Server (NTRS)

    Pohorille, A.; Hoehler, T. M.

    2017-01-01

    For the first time since Viking, NASA is considering missions that would include life detection as a primary objective, making it critical to develop and evaluate a diverse set of strategies for seeking evidence of life. The central question is: what should be the target of our search that, if found, would constitute a near-certain evidence for life? Since life on icy moons might be quite different from terrestrial life, we should concentrate on features of biological systems that are considered universal and are unlikely to emerge through abiotic means.

  6. Thermo-chemical Ice Penetrator for Icy Moons

    NASA Astrophysics Data System (ADS)

    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

  7. Fitting Orbits to Jupiter's Moons with a Spreadsheet.

    ERIC Educational Resources Information Center

    Bridges, Richard

    1995-01-01

    Describes how a spreadsheet is used to fit a circular orbit model to observations of Jupiter's moons made with a small telescope. Kepler's Third Law and the inverse square law of gravity are observed. (AIM)

  8. Fitting Orbits to Jupiter's Moons with a Spreadsheet.

    ERIC Educational Resources Information Center

    Bridges, Richard

    1995-01-01

    Describes how a spreadsheet is used to fit a circular orbit model to observations of Jupiter's moons made with a small telescope. Kepler's Third Law and the inverse square law of gravity are observed. (AIM)

  9. Large Icy Diapirs and Small Icy Satellites: Reorientation of Mini-Moons

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Nimmo, F.; Moore, J. M.

    2005-12-01

    A class of icy satellites ~400 - 500 km in diameter are large enough that they can experience significant tidal heating (Miranda and Enceladus), while small enough that rising diapirs could significantly perturb the bodies' moments of inertia. If these "mini-moons" are heated sufficiently for differentiation and/or internal convection, the resultant low-density plumes may affect inertia moments enough to trigger satellite reorientation relative to the primary planet. Here we emphasize the case of Miranda and its three large coronae, which are inferred to have formed above large-scale diapiric upwellings [1]. Their locations on the greatest inertia axis (near the south pole) and the intermediate inertia axis (along the leading-trailing axis) suggest that coronae are negative density anomalies that have led to satellite reorientation [2]. The Miranda reorientation hypothesis is further supported by fresh crater distributions [3] and structural evidence [4]. True polar wander of the Earth, promoted by convection and associated continental drift, depends on the perturbation timescale relative to the timescale of viscous relaxation [e.g. 5]. Applying similar arguments to a warm and hydrostatic Miranda, we find that a corona-scale (60° width) icy diapir 100 kg/m3 less dense than its surroundings could induce significant (tens of degrees) reorientation, if the ratio of the diapir lifetime τconv to the ice shell relaxation time τR exceeds 103. For Enceladus, large reorientations can occur even more readily, if τconv / τR exceeds 102. In contrast, a cold mini-moon with a frozen-in hydrostatic figure (Mimas and Proteus) would not easily reorient, as a density anomaly would need to overcome the large difference in principal moments [6]. We find that this latter scenario is consistent with the 130 km crater Herschel not having reoriented Mimas. Mini-moon reorientation allows for some interesting possibilities: a large density anomaly could reorient a warm moon while the

  10. Radar glory from buried craters on icy moons

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1986-01-01

    Three ice-covered moons of Jupiter, in comparison with rocky planets and earth's moon, produce radar echoes of astounding strengths and bizarre polarizations. Scattering from buried craters can explain these and other anomalous properties of the echoes. The role of such craters is analogous to that of the water droplets that create the apparition known as 'the glory', the optically bright region surrounding an observer's shadow on a cloud. Both situations involve the electromagnetic phenomenon of total internal reflection at a dielectric interface, operating in a geometry that strongly favors exact backscattering. Dim surface craters are transformed into bright glory holes by being buried under somewhat denser material, thereby increasing the intensity of their echoes by factors of hundreds. The dielectric interface thus formed at the crater walls nicely accounts for the unusual polarizations of the echoes.

  11. Radar glory from buried craters on icy moons

    NASA Astrophysics Data System (ADS)

    Eshleman, Von R.

    1986-10-01

    Three ice-covered moons of Jupiter, in comparison with rocky planets and earth's moon, produce radar echoes of astounding strengths and bizarre polarizations. Scattering from buried craters can explain these and other anomalous properties of the echoes. The role of such craters is analogous to that of the water droplets that create the apparition known as 'the glory', the optically bright region surrounding an observer's shadow on a cloud. Both situations involve the electromagnetic phenomenon of total internal reflection at a dielectric interface, operating in a geometry that strongly favors exact backscattering. Dim surface craters are transformed into bright glory holes by being buried under somewhat denser material, thereby increasing the intensity of their echoes by factors of hundreds. The dielectric interface thus formed at the crater walls nicely accounts for the unusual polarizations of the echoes.

  12. Stagnant lid convection in the outer shell of icy moons

    NASA Astrophysics Data System (ADS)

    Yao, Chloe; Deschamps, Frédéric; Tackley, Paul; Lowman, Julian; Sanchez-Valle, Carmen

    2013-04-01

    In the past decade, from both theoretical studies and spacecraft missions measurements, the internal structure of large icy moons including a subsurface ocean has gained an increasing support. The exact thickness of subsurface ocean, if present, depends on the detailed thermal evolution of each moon, and on its primordial composition. A crucial process is the heat transfer through the outer ice I layer, which controls the cooling of the satelitte interior. Convection is the most likely and efficient way to transfer heat through this layer, but the regime of convection (and therefore the heat transfer) depends on the rheology of the fluid. The viscosity of ice is strongly temperature dependent and thermal convection in the outer ice shell follows a stagnant lid regime : it means that a conductive stagnant lid forms at the top of the system, and convection is confined in a sublayer. Previous numerical studies including strongly temperature-dependent viscosities have already been performed in 2D Cartesian geometry allowing the determination of scaling laws relating the mean temperature and heat flux to the vigor of convection (described by the Rayleigh number) and the ratio of the top to the bottom viscosity, but 3D spherical geometry may provide a more accurate description of convection within the outer ice layer of icy moons. In this work, we model the heat transfer in spherical shells for a strongly temperature-dependent viscosity fluid heated from below. We use StagYY to run simulations for different ratios of the inner to outer radii of the ice layer (f), Rayleigh number (Ra), and thermal viscosity contrast (Δη). The inversion of the results of more than 30 numerical experiments allows the determination of scaling laws for the temperature of the well-mixed interior and surface heat flux. In particular, we find that depending on the curvature, the stagnant lid regime does not appear for the same values of the Rayleigh number and the viscosity contrast. These

  13. Icy moon exospheres: the interface between Jovian environment and satellite surfaces as a key scientific target for JUICE

    NASA Astrophysics Data System (ADS)

    Plainaki, Christina; Milillo, Anna; Grassi, Davide; Mura, Alessandro; Massetti, Stefano; Orsini, Stefano; Mangano, Valeria; De Angelis, Elisabetta; Rispoli, Rosanna

    2016-04-01

    The exospheres of Jupiter's icy satellites -often referred to as tenuous atmospheres- represent the actual interface between the surfaces of these moons and the giant planet's environment. In this perspective, their characterization is of key importance to achieve a fully understanding of the alteration processes induced on the icy surfaces by the radiation environment. Therefore, a full interpretation of the surface data and a thorough understanding of the surface evolution history, have as a necessary prerequisite the accurate determination of the role of the exospheres in the interactions between the icy moons and the Jupiter's magnetospheric environment. Moreover, in order to understand the mass and energy exchange between satellites and Jovian environment, the detailed characterization of the exosphere as a boundary region between the moon and the giant planet's magnetosphere, is fundamental. In this paper, we show that the achievement of the science objectives of the JUICE mission related to the icy satellites exospheres will be feasible only through an interdisciplinary approach characterized by coordinated observation scenarios and joint campaigns in payload operations. It is evidenced that it is of key importance to measure - in the larger possible extent - the following quantities: density of neutral species; density of ionosphere and charged particles fluxes; efficiency of interactions of the exosphere with particle and photon radiation fields. Through the planning of potential synergies between different datasets to be obtained during different mission phases, the current paper aims to contribute to the achievement of both of the JUICE mission's Key Science Goals, i.e. 1) the characterization of Ganymede, Europa and Callisto as planetary objects and potential habitats and 2) the exploration of the Jupiter system as an archetype for gas giants. The suggested planning for joint observations by different JUICE payload instruments could be extended later in

  14. Automated Estimation of the Orbital Parameters of Jupiter's Moons

    NASA Astrophysics Data System (ADS)

    Western, Emma; Ruch, Gerald T.

    2016-01-01

    Every semester the Physics Department at the University of St. Thomas has the Physics 104 class complete a Jupiter lab. This involves taking around twenty images of Jupiter and its moons with the telescope at the University of St. Thomas Observatory over the course of a few nights. The students then take each image and find the distance from each moon to Jupiter and plot the distances versus the elapsed time for the corresponding image. Students use the plot to fit four sinusoidal curves of the moons of Jupiter. I created a script that automates this process for the professor. It takes the list of images and creates a region file used by the students to measure the distance from the moons to Jupiter, a png image that is the graph of all the data points and the fitted curves of the four moons, and a csv file that contains the list of images, the date and time each image was taken, the elapsed time since the first image, and the distances to Jupiter for Io, Europa, Ganymede, and Callisto. This is important because it lets the professor spend more time working with the students and answering questions as opposed to spending time fitting the curves of the moons on the graph, which can be time consuming.

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

    NASA Astrophysics Data System (ADS)

    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

  16. Investigating Saturn's Icy Moons using HST/STIS

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Noll, K. S.; Spencer, J. R.

    2015-12-01

    The inner moons of Saturn - Mimas, Enceladus, Tethys, Dione and Rhea - exhibit remarkable large-scale albedo and color variations. These trends can be linked to a combination of the unique exogenic processes occurring the Saturn system, including E-ring grain bombardment and charged particle bombardment. One of the fascinating characteristics of the Saturn system is that the icy satellites, though their surface compositions are dominated by water ice, are spectrally red - they are absorbing in the ultraviolet-visible wavelength region (wavelengths <~550 nm) - a spectral feature not typical of pure water ice. In fact, the existing data show that in the UV, absorptions appear to be present superimposed on the overall red slope. Thus, though Cassini instruments have learned much about the surfaces of the icy moons, a basic question that remains is: What is their surface composition and what are the species or processes that cause these UV absorptions? Cassini's spectral coverage is lacking in precisely the near-UV wavelength regime in which the satellites appear to absorb most strongly. To resolve this issue and determine some understanding of the surface species present, we have obtained data using HST/STIS (Space Telescope Imaging Spectrograph). We have utilized the STIS G230L detector to obtain high SNR spectra in the 180-320 nm region along with short G430L exposures to obtain spectra in the 320-570 nm range, to completely fill in the Cassini gap in spectral coverage. Full-disk measurements have been made of the trailing and leading hemispheres of Mimas, Dione and Rhea; a spectrum of Enceladus was also obtained. We report on the results. In particular, we discuss implications for the presence of ammonia, ozone and organics.

  17. Onset of convection and differentiation in the hydrated cores of icy moons.

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Reynard, Bruno

    2013-04-01

    The Galileo mission to Jupiter and the Cassini/Huygens mission to Saturn have revealed that the three large Jovian icy moons and Titan, Saturn's largest satellite, are at least partly differentiated. Their normalized moments of inertia are smaller than 2/5, which is the value for undifferentiated moons. We present new simulations of the thermal evolution, dehydration process, differentiation, and onset of convection in the hydrated cores of large icy satellites. The motivation is to investigate whether convection can start before dehydration starts in the cores. Such a process would prevent differentiation. The viscosity of antigorite, the hydrated silicate supposed to compose the hydrated cores, is strongly non-Newtonian and weakly temperature-dependent. The cores are volumetrically heated by natural radioactivity. We have adapted the theory developed for non-Newtonian fluids heated from below [1] to the case of volumetrically heated fluids. A recent review [2] of the physical parameters relevant to the thermal evolution of hydrated cores made of antigorite provides values quite different from those used in previous studies [3,4], which seriously modifies the results of previous simulations including the predicted present interior structure of the large icy satellites. The numerical simulations presented in this study suggest that the inner part of the hydrated core of icy moons would dehydrate for a large range of parameters, the most important of which is the amount of 40K. The outer core would remain hydrated. It is shown that convection could start in the outer core for large values of internal heating. Implications for subsequent thermal evolution are being investigated. [1] Solomatov V.S. (1995) Scaling of temperature and stressdependent viscosity convection; Phys. Fluids 7, 266; doi: 10.1063/1.868624. [2] Reynard B. (2012) Serpentine in active subduction zones. Lithos, doi: 10.1016/j.lithos.2012.10.012 [3] Grinrod P.M., A.D. Fortes, F. Nimmo, D.L. Feltham

  18. Cassini CIRS characterization of icy moon surface composition

    NASA Astrophysics Data System (ADS)

    Young, Cindy L.; Wray, J. J.; Spencer, J. R.; Clark, R. N.; Hand, K. P.

    2013-10-01

    Compositional studies of Saturn’s icy moons were one of the original science goals for Cassini’s Composite Infrared Spectrometer (CIRS) [1], but to date they have received less attention than measurements of atmospheres, surface temperatures and thermophysical properties across the Saturn system. Recent Cassini Visual and Infrared Mapping Spectrometer (VIMS) data have shown tantalizing evidence of possible organic molecules and metals on several Saturnian moon surfaces [e.g., 2,3], but the stronger fundamental absorptions in the mid-IR would allow confirmation of these constituents and more specific identifications. The spectral region covered by CIRS focal planes 3 and 4 is rich in emissivity features due to both simple and complex molecules [4], but the study of emissivity variations in this region is often challenged by low signal to noise ratios for individual spectra. We present an approach to average CIRS spectra from the full icy moon dataset on the Planetary Data System to increase signal-to-noise and use emissivity spectra to constrain surface compositions. A first look at CIRS spectra averaged over the dark terrain of Iapetus is presented. Preliminary results show that averaging greatly reduces noise in radiance and emissivity spectra, revealing a potential spectral feature that does not correspond to any known instrument artifact. We are working to identify it as a possible non-ice contribution to Iapetus’ surface composition. [1] Flasar, F.M., et al. (2004), Exploring the Saturn system in the thermal infrared: The Composite Infrared Spectrometer, Space Sci. Rev., 115, 169-297. [2] Brown, R.H., et al. (2006), Composition and physical properties of Enceladus’ surface, Science, 311, 1425-1428. [3] Clark, R.N., et al. (2012), The surface composition of Iapetus: Mapping results from Cassini VIMS, Icarus, 218, 831-860. [4] Hand, K.P., Chyba, C.F., Priscu, J.C., Carlson, R.W. & K.H. Nealson (2009), Astrobiology and the Potential for Life on Europa. In

  19. Animation: 'Great Lake' on Jupiter's Moon Europa

    NASA Image and Video Library

    Data from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupi...

  20. Icy Shell Stresses from Despinning and Thickness Variations: Applications to Rifting on Icy Moons of Saturn

    NASA Astrophysics Data System (ADS)

    McGovern, P. J., Jr.; Byrne, P. K.; Collins, G. C.; Schenk, P.

    2016-12-01

    Saturn's mid-sized icy moons Rhea, Tethys, and Dione all exhibit N-S-oriented rift zones, concentrated in the moon's trailing hemisphere (on Rhea and Dione) or at the sub-Saturn point (on Tethys). The highly concentrated distribution of extensional strain on these bodies can thus be characterized as having a strong "degree-1" component (i.e., a maximum and a minimum in a planetary circumference), with arguably a "degree-2" component (two maxima alternating with two minima) on Dione. To evaluate stress state scenarios compatible with these observed strains, we constructed models of a Dione-sized moon with the COMSOL Multiphysics finite-element code. The models feature an icy lithosphere overlying an inviscid layer, and are configured as a 1/8-sphere invoking 3 symmetry planes to represent a full sphere. (This configuration precludes treatment of anti-symmetric structure or loading, e.g., odd degrees.) We simulated stresses arising from tidal downspin (by applying a perturbation to the gravitational acceleration) and stresses from directly modeled, initially isostatic, shell thickness variations. Where both stress states interacted, we found that the magnitudes of the "isostatic" stresses (as the topography tries to return to a uniform state) overwhelmed those induced by changes in spin rate. For moderate values of shell thickness ( 0.1-0.5×radius), despinning of a uniform-thickness shell resulted in an equatorial province of N-S-oriented thrust faulting, a mid-latitude province of strike-slip faulting, and a polar province of E-W-oriented normal faulting. Shells with thickness variations of the form k cos(2×latitude) showed similar stress and strain patterns to the pure despinning case for positive k (thickening at the equator), but negative k (thinning at the equator) produced E-W-oriented extension over all but the polar region, and N-S-oriented compression everywhere. Only the latter pattern is consistent with the N-S-orientations of the rift zones on Rhea

  1. Reorientation of the rotation axis of triaxial viscoelastic icy moons: Europa and Titan

    NASA Astrophysics Data System (ADS)

    Jara Orue, H. M.; Vermeersen, L. L. A.

    2011-10-01

    We provide an analysis of the rotational response of triaxial viscoelastic icy moons, focusing on the free rotational behavior of Europa and Titan. In a similar way as for terrestrial planets, the rotational behavior of icy moons is dominated by a secular shift of the pole and the periodic Chandler wobble. However, unlike terrestrial planets, the Chandler wobble of icy moons is associated with the viscoelastic response of the layers located below the ocean. The fast relaxation of low-viscous ice layers induces additional wobble frequencies. However, these wobbles are generally weak compared to the strength of the main Chandler wobble.

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

    NASA Astrophysics Data System (ADS)

    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).

  3. Polymerization of Building Blocks of Life on Europa and Other Icy Moons.

    PubMed

    Kimura, Jun; Kitadai, Norio

    2015-06-01

    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 temperature on Europa is 120 and 80 K in the equatorial region and polar region, respectively. At such low temperatures, Gibbs energies of polymerization become negative, and the estimated thermal structure of the icy crust should contain a shallow region (i.e., at a depth of only a few kilometers) favorable for polymerization. Investigation of the possibility of organic monomer polymerization on icy moons could provide good constraints on the origin and early evolution of extraterrestrial life.

  4. Saturn and 4 Icy Moons in Natural Color

    NASA Image and Video Library

    1998-06-08

    This approximate natural-color image shows Saturn, its rings, and four of its icy satellites. Three satellites (Tethys, Dione, and Rhea) are visible against the darkness of space, and another smaller satellite (Mimas) is visible against Saturn's cloud tops very near the left horizon and just below the rings. The dark shadows of Mimas and Tethys are also visible on Saturn's cloud tops, and the shadow of Saturn is seen across part of the rings. Saturn, second in size only to Jupiter in our Solar System, is 120,660 km (75,000 mi) in diameter at its equator (the ring plane) but, because of its rapid spin, Saturn is 10% smaller measured through its poles. Saturn's rings are composed mostly of ice particles ranging from microscopic dust to boulders in size. These particles orbit Saturn in a vast disk that is a mere 100 meters (330 feet) or so thick. The rings' thinness contrasts with their huge diameter--for instance 272,400 km (169,000 mi) for the outer part of the bright A ring, the outermost ring visible here. The pronounced concentric gap in the rings, the Cassini Division (named after its discoverer), is a 3500-km wide region (2200 mi, almost the width of the United States) that is much less populated with ring particles than the brighter B and A rings to either side of the gap. The rings also show some enigmatic radial structure ('spokes'), particularly at left. This image was synthesized from images taken in Voyager's blue and violet filters and was processed to recreate an approximately natural color and contrast. http://photojournal.jpl.nasa.gov/catalog/PIA00400

  5. Looking for planetary moons in the spectra of distant Jupiters.

    PubMed

    Williams, D M; Knacke, R F

    2004-01-01

    More than 100 nearby stars are known to have at least one Jupiter-sized planet. Whether any of these giant gaseous planets has moons is unknown, but here we suggest a possible way of detecting Earth-sized moons with future technology. The planned Terrestrial Planet Finder observatory, for example, will be able to detect objects comparable in size to Earth. Such Earth-sized objects might orbit their stars either as isolated planets or as moons to giant planets. Moons of Jovian-sized planets near the habitable zones of main-sequence stars should be noticeably brighter than their host planets in the near-infrared (1-4 microm) if their atmospheres contain methane, water, and water vapor, because of efficient absorption of starlight by these atmospheric components. By taking advantage of this spectral contrast, future space observatories will be able to discern which extrasolar giant planets have Earth-like moons capable of supporting life.

  6. Hubble Catches Jupiter's Largest Moon Going to the 'Dark Side'

    NASA Image and Video Library

    2017-09-28

    Hubble Catches Jupiter's Largest Moon Going to the 'Dark Side' HST/WFPC2 Image of Jupiter and Ganymede Taken April 9, 2007 NASA's Hubble Space Telescope has caught Jupiter's moon Ganymede playing a game of "peek-a-boo." In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant planet. Ganymede completes an orbit around Jupiter every seven days. Because Ganymede's orbit is tilted nearly edge-on to Earth, it routinely can be seen passing in front of and disappearing behind its giant host, only to reemerge later. Composed of rock and ice, Ganymede is the largest moon in our solar system. It is even larger than the planet Mercury. But Ganymede looks like a dirty snowball next to Jupiter, the largest planet in our solar system. Jupiter is so big that only part of its Southern Hemisphere can be seen in this image. Hubble's view is so sharp that astronomers can see features on Ganymede's surface, most notably the white impact crater, Tros, and its system of rays, bright streaks of material blasted from the crater. Tros and its ray system are roughly the width of Arizona. The image also shows Jupiter's Great Red Spot, the large eye-shaped feature at upper left. A storm the size of two Earths, the Great Red Spot has been raging for more than 300 years. Hubble's sharp view of the gas giant planet also reveals the texture of the clouds in the Jovian atmosphere as well as various other storms and vortices. Astronomers use these images to study Jupiter's upper atmosphere. As Ganymede passes behind the giant planet, it reflects sunlight, which then passes through Jupiter's atmosphere. Imprinted on that light is information about the gas giant's atmosphere, which yields clues about the properties of Jupiter's high-altitude haze above the cloud tops. This color image was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors. For

  7. Core Shadow Zones of Terrestrial Planets and Icy Moons

    NASA Astrophysics Data System (ADS)

    Sohl, F.; Knapmeyer, M.; Gassner, L.; Lange, C.; Wagner, F. W.

    2011-12-01

    The internal dynamics of a planetary core is strongly dependent on its total radius. The volume/surface ratio of a planetary core is linked directly to the outgoing heat flux, which is also an indicator for the element partition between the surrounding mantle and the core. The determination of the core radius is thus an elementary step to better understand the origin and evolution of a planetary body. An observable that has been shown to serve as indicator for core size is the extent of the seismological (P-wave-) core shadow. It appears that the variation of seismic velocities with depth is dominated by quadratic terms, if not an essentially depth independent velocity can be assumed. The observed and predicted core shadow extents of many terrestrial planet models, computed as function of the relative core radius, thus align closely to the analytically derived function for objects with constant velocity profiles. The heavier solar system terrestrial planets, especially Venus and Earth, show the largest deviation from the relation between core radius and shadow width that holds for small bodies. For terrestrial planets more massive than Earth, as found for several exoplanets, the increasing internal pressure would cause increased curvature of tentative seismic rays and thus a more pronounced excursion from the relation for bodies with depth-independent elastic parameters. For Titan, a geophysical network has been suggested as a follow up to the highly successful Cassini-Huygens mission that is currently orbiting Saturn. Titan belongs to the class of weakly differentiated icy moons, which consist of an icy crust, underlain by a deep internal ocean and a central ice-rock body. Unlike any other moon in the solar system, Titan has a thick atmosphere that gives rise to surface processes resembling those on Earth. The goal of the proposed network is an improved understanding of the interactions between atmosphere, surficial ice and a putative subsurface water ocean. Key

  8. Polymerization of Building Blocks of Life on Europa and Other Icy Moons

    PubMed Central

    Kitadai, Norio

    2015-01-01

    Abstract 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 temperature on Europa is 120 and 80 K in the equatorial region and polar region, respectively. At such low temperatures, Gibbs energies of polymerization become negative, and the estimated thermal structure of the icy crust should contain a shallow region (i.e., at a depth of only a few kilometers) favorable for polymerization. Investigation of the possibility of organic monomer polymerization on icy moons could provide good constraints on the origin and early evolution of extraterrestrial life. Key Words: Planetary science—Europa—Planetary habitability and biosignatures—Extraterrestrial life—Extraterrestrial organic compounds. Astrobiology 15, 430–441. PMID:26060981

  9. Modeling the Neutral Gas and Plasma Environment of Jupiter's Moon Europa

    NASA Astrophysics Data System (ADS)

    Rubin, Martin; Tenishev, Valeriy; Hansen, Kenneth; Jia, Xianzhe; Combi, Michael; Gombosi, Tamas

    Jupiter's moon Europa has a thin gravitationally bound neutral atmosphere, which is mostly created through sputtering of high-energy ions impacting on its icy surface. The interaction of Europa with the Jovian magnetosphere is simulated using the magnetohydrodynamics (MHD) model BATSRUS. We start from the model by Kabin et al. [JGR, Vol. 104, No. A9, (1999)], which accounts for the exospheric mass loading, ion-neutral charge exchange, and ion-electron recombination. The derived magnetic field topology and plasma speeds are used to calculate the Lorentz force for our test particle Monte Carlo model. We use this model to simulate Europa's plasma and neutral environment by tracking particles created on the moon's surface by sputtering or sublimation, through dissociation and/or ionization in the atmosphere, or entering the system from Jupiter's magnetosphere as high energy ions. Neutral particle trajectories are followed by solving the equation of motion in Europa's gravity field whereas the ion population is additionally subject to the Lorentz force. We will show preliminary results of this work with application to the missions to the Jupiter system currently under consideration by NASA (JEO) and ESA (JGO).

  10. Simon Marius vs. Galileo: Who First Saw Moons of Jupiter?

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Van Helden, Albert

    2016-10-01

    In his almanac for 1612 and book Mundus Iovalis of 1614, Simon Marius in Germany reported his discovery of moons around Jupiter, which he started writing down in late 1609 in the Julian calendar, which translated to 8 January 1610 in the Gregorian calendar in use by Galileo in Italy. Is Marius to be believed? Galileo certainly did not. But a Dutch jury of experts about three hundred years later reported that they validated the claim that Marius independently discovered the moons of Jupiter one day after Galileo first both saw and wrote down his discovery! There is no doubt that the names Io, Europa, Ganymede, and Callisto came from Marius (to whom they were suggested by Kepler). See JMP's Journal for the History of Astronomy article, 46(2), 218-234 (2015).Marius wrote that he had been observing the moons around Jupiter since November 1609 (Julian), using a neighboring nobleman's telescope, which would mean that he actually saw the Jupiter satellites first (though publish or perish). Whether this feat was technically possible comes down to discussions of the capabilities of telescopes in the early 17th century.The quadricentennial of Marius's book was celebrated in Nuremberg with a symposium that is now in press in German with an English translation expected. One of us (AVH) has recently prepared a complete English translation of Marius's book, superseding the partial translation made 100 years ago. There is no evidence that, whether he saw what we now call the Galilean satellites first or not, Marius appreciated their cosmological significance the way that Galileo soon did. And Marius was certainly the first to publish tables of the moons of Jupiter.We thank the Chapin Library of Williams College and the Huntington Library for assistance with first editions of Marius's 1614 book, and we thank Pierre Leich of the Simon Marius Gesellschaft for his consultations.

  11. Tour of Jupiter Galilean moons: Winning solution of GTOC6

    NASA Astrophysics Data System (ADS)

    Colasurdo, Guido; Zavoli, Alessandro; Longo, Alessandro; Casalino, Lorenzo; Simeoni, Francesco

    2014-09-01

    The paper presents the trajectory designed by the Italian joint team Politecnico di Torino & Sapienza Università di Roma (Team5), winner of the 6th edition of the Global Trajectory Optimization Competition (GTOC6). In the short time available in these competitions, Team5 resorted to basic knowledge, simple tools and a powerful indirect optimization procedure. The mission concerns a 4-year tour of the Jupiter Galilean moons. The paper explains the strategy that was preliminarily devised and eventually implemented by looking for a viable trajectory. The first phase is a capture that moves the spacecraft from the arrival hyperbola to a low-energy orbit around Jupiter. Six series of flybys follow; in each one the spacecraft orbits Jupiter in resonance with a single moon; criteria to construct efficient chains of resonant flybys are presented. Transfer legs move the spacecraft from resonance with a moon to another one; precise phasing of the relevant moons is required; mission opportunities in a 11-year launch window are found by assuming ballistic trajectories and coplanar circular orbits for the Jovian satellites. The actual trajectory is found by using an indirect technique.

  12. Is Jupiter's Moon Amalthea a Captured Trojan Asteroid?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would form at this Jovian orbit had Amalthea moon condensed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter and especially because of its small size relative to the Galilean satellites Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of ice. Most likely therefore Amalthea originally condensed as a planetesimal within the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  13. Project GALILEO: Farewell to the Major Moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Theilig, E.

    2002-01-01

    After a six year odyssey, Galileo has completed its survey of the large moons of Jupiter. In the four years since the end of the primary mission, Galileo provided new insights into the fundamental questions concerning Jupiter and its moons and magnetosphere. Longevity, changing orbital geometry, and multiple flybys afforded the opportunity to distinguish intrinsic versus induced magnetic fields on the Galilean moons, to characterize the dusk side of the magnetosphere, to acquire high resolution observations supporting the possibility of subsurface water within Europa, Ganymede, and Callisto, and to monitor the highly dynamic volcanic activity of Io. In January 2002, a final gravity assist placed the spacecraft on a two-orbit trajectory culminating in a Jupiter impact in September 2003. With the successful completion of the Io encounters, plans are being made for the final encounter of the mission. In November 2002, the spacecraft will fly one Jupiter radius above the planet's cloud-tops, sampling the inner magnetosphere and the gossamer rings. The trajectory will take Galileo close enough to Amalthea, (a small inner moon) to obtain the first gravity data for this body. Because a radiation dose of 73 krads is expected on this encounter, which will bring the total radiation dose to greater than four times the spacecraft design limits, the command sequence has to account for the possibility of subsystem failure and the loss of spacecraft control after this perijove passage. One of the primary objectives this year has been to place the spacecraft on a trajectory to impact Jupiter on orbit 35. Galileo's discovery of water beneath the frozen surface of Europa raised concerns about forward contamination by inadvertently impacting that moon and resulted in an end of mission requirement to dispose of the spacecraft. A risk assessment of the final two Io encounters was performed to manage the project's ability to meet this requirement. Radiation affected the extended mission

  14. Constraints on a Water Layer in Jupiter's moon Ganymede from Tidal Deformation and Forced Librations

    NASA Astrophysics Data System (ADS)

    Vermeersen, B. L. A.; Jara Orue, H. M.

    2016-12-01

    One of the major scientific objectives of ESA's JUpiter ICy moons Explorer (JUICE) mission, scheduled for launch in 2022 and planned to arrive at the Jovian system in 2030, is to characterize the hypothesized internal water ocean and overlying ice shell of Jupiter's largest moon Ganymede. As part of the strategy developed to realize this objective, the tidal response of Ganymede's interior will be constrained by JUICE's measurements of surface displacements by the Ganymede Laser Altimeter (GALA) instrument and variations in the gravitational potential by the 3GM radio science package due to the acting diurnal tides. Here we determine, using a viscoelastic Maxwell rheological model, the tidal response at the surface of Ganymede for several plausible internal configurations in order to analyse the relation between the tidal response and the geophysical parameters that characterize Ganymede's interior. Similarly to the case of Jupiter's smallest icy satellite Europa, the tidal response of Ganymede in the presence of a subsurface ocean mostly depends on structural (thickness, density) and rheological (rigidity, viscosity) properties of the ice-I shell. Tidal-induced vertical surface displacements could be as large as 3.5 m if there is an internal water layer. Nevertheless, the dependence of the tidal response on several geophysical parameters of the interior, in particular thickness and rigidity of the ice-I shell, does not allow for an unambiguous determination of depth and thickness of the water layer from tidal measurements alone. Additional constraints could be provided by measuring forced longitudinal librations at the surface, as their amplitudes are more sensitive to ice rigidity than to thickness of the ice shell.

  15. Detection of an oxygen atmosphere on Jupiter's moon Europa.

    PubMed

    Hall, D T; Strobel, D F; Feldman, P D; McGrath, M A; Weaver, H A

    1995-02-23

    Europa, the second large satellite out from Jupiter, is roughly the size of Earth's Moon, but unlike the Moon, it has water ice on its surface. There have been suggestions that an oxygen atmosphere should accumulate around such a body, through reactions which break up the water molecules and form molecular hydrogen and oxygen. The lighter H2 molecules would escape from Europa relatively easily, leaving behind an atmosphere rich in oxygen. Here we report the detection of atomic oxygen emission from Europa, which we interpret as being produced by the simultaneous dissociation and excitation of atmospheric O2 by electrons from Jupiter's magnetosphere. Europa's molecular oxygen atmosphere is very tenuous, with a surface pressure about 10(-11) that of the Earth's atmosphere at sea level.

  16. 2.7- to 4.1-micron spectrophotometry of icy satellites of Saturn and Jupiter

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Feierberg, M. A.

    1985-01-01

    Spectrophotometry is presented in the 2.7-4.1 micrometer spectral region for icy satellites of Saturn (Tethys, Dione, Rhea, Iapetus and Hyperion) and Jupiter (Europa, Ganymede and Callisto). The 3.6-micrometer reflectance peak characteristic of fine-grained water ice is observed prominently on the satellites of Saturn, faintly on the leading side of Europa, and not at all on Ganymede, Callisto or the dark side of Iapetus. The spectral reflectances of these icy satellites may be affected by their equilibrium surface temperatures and magnetospheric effects.

  17. Numerical investigation of mapping orbits about Jupiter's icy moons

    NASA Technical Reports Server (NTRS)

    Aiello, John

    2005-01-01

    A proposed mission that would orbit Callisto, Ganymede, and Europa will require low altitude, high inclination orbits for gravity and surface mapping. This paper explores the dynamics of these orbits by direct propagation against an ephemeris model. Initial conditions within the context of a mapping mission's likely requirements are considered. The results complement the analytical studies and reveal additional dependencies.

  18. Hubble Provides Infrared View of Jupiter's Moon, Ring, and Clouds

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Probing Jupiter's atmosphere for the first time, the Hubble Space Telescope's new Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides a sharp glimpse of the planet's ring, moon, and high-altitude clouds.

    The presence of methane in Jupiter's hydrogen- and helium-rich atmosphere has allowed NICMOS to plumb Jupiter's atmosphere, revealing bands of high-altitude clouds. Visible light observations cannot provide a clear view of these high clouds because the underlying clouds reflect so much visible light that the higher level clouds are indistinguishable from the lower layer. The methane gas between the main cloud deck and the high clouds absorbs the reflected infrared light, allowing those clouds that are above most of the atmosphere to appear bright. Scientists will use NICMOS to study the high altitude portion of Jupiter's atmosphere to study clouds at lower levels. They will then analyze those images along with visible light information to compile a clearer picture of the planet's weather. Clouds at different levels tell unique stories. On Earth, for example, ice crystal (cirrus) clouds are found at high altitudes while water (cumulus) clouds are at lower levels.

    Besides showing details of the planet's high-altitude clouds, NICMOS also provides a clear view of the ring and the moon, Metis. Jupiter's ring plane, seen nearly edge-on, is visible as a faint line on the upper right portion of the NICMOS image. Metis can be seen in the ring plane (the bright circle on the ring's outer edge). The moon is 25 miles wide and about 80,000 miles from Jupiter.

    Because of the near-infrared camera's narrow field of view, this image is a mosaic constructed from three individual images taken Sept. 17, 1997. The color intensity was adjusted to accentuate the high-altitude clouds. The dark circle on the disk of Jupiter (center of image) is an artifact of the imaging system.

    This image and other images and data received from the Hubble Space Telescope are

  19. Hubble Provides Infrared View of Jupiter's Moon, Ring, and Clouds

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Probing Jupiter's atmosphere for the first time, the Hubble Space Telescope's new Near Infrared Camera and Multi-Object Spectrometer (NICMOS) provides a sharp glimpse of the planet's ring, moon, and high-altitude clouds.

    The presence of methane in Jupiter's hydrogen- and helium-rich atmosphere has allowed NICMOS to plumb Jupiter's atmosphere, revealing bands of high-altitude clouds. Visible light observations cannot provide a clear view of these high clouds because the underlying clouds reflect so much visible light that the higher level clouds are indistinguishable from the lower layer. The methane gas between the main cloud deck and the high clouds absorbs the reflected infrared light, allowing those clouds that are above most of the atmosphere to appear bright. Scientists will use NICMOS to study the high altitude portion of Jupiter's atmosphere to study clouds at lower levels. They will then analyze those images along with visible light information to compile a clearer picture of the planet's weather. Clouds at different levels tell unique stories. On Earth, for example, ice crystal (cirrus) clouds are found at high altitudes while water (cumulus) clouds are at lower levels.

    Besides showing details of the planet's high-altitude clouds, NICMOS also provides a clear view of the ring and the moon, Metis. Jupiter's ring plane, seen nearly edge-on, is visible as a faint line on the upper right portion of the NICMOS image. Metis can be seen in the ring plane (the bright circle on the ring's outer edge). The moon is 25 miles wide and about 80,000 miles from Jupiter.

    Because of the near-infrared camera's narrow field of view, this image is a mosaic constructed from three individual images taken Sept. 17, 1997. The color intensity was adjusted to accentuate the high-altitude clouds. The dark circle on the disk of Jupiter (center of image) is an artifact of the imaging system.

    This image and other images and data received from the Hubble Space Telescope are

  20. Instrumentation for Testing Whether the Icy Moons of the Gas and Ice Giants Are Inhabited.

    PubMed

    Chela-Flores, Julian

    2017-10-11

    Evidence of life beyond Earth may be closer than we think, given that the forthcoming missions to the Jovian system will be equipped with instruments capable of probing Europa's icy surface for possible biosignatures, including chemical biomarkers, despite the strong radiation environment. Geochemical biomarkers may also exist beyond Europa on icy moons of the gas giants. Sulfur is proposed as a reliable geochemical biomarker for approved and forthcoming missions to the outer solar system. Key Words: JUICE mission-Clipper mission-Geochemical biomarkers-Europa-Moons of the ice giants-Geochemistry-Mass spectrometry. Astrobiology 17, xxx-xxx.

  1. Interior Models and Gravity Field of Jupiter's Moon Amalthea

    NASA Astrophysics Data System (ADS)

    Weinwurm, G.; Weber, R.

    2003-12-01

    Before its final plunge into Jupiter in September 2003, GALILEO made a last visit to Jupiters moon Amalthea. This final flyby of the spacecrafts successful mission occurred on November 5, 2002. In order to analyse the spacecraft data with respect to Amaltheas gravity field, interior models of the moon had to be provided. The method used for this approach is based on the numerical integration of infinitesimal volume elements, which are calculated by the scale factors of a three-axial ellipsoid (elliptic coordinates). To derive the gravity field coefficients of the body, the second method of Neumann was applied. Based on the spacecraft trajectory data provided by the Jet Propulsion Laboratory, GALILEOs velocity perturbations at closest approach could be calculated. We have derived the harmonic coefficients of Amaltheas gravity field up to degree and order six, for both homogeneous and reasonable heterogeneous cases. Based on these numbers we calculated the impact on the trajectory of GALILEO and compared it to existing Doppler data. Although no two-way Doppler-data was available during the flyby and the harmonic coefficients of the gravity field are buried in the one-way Doppler-noise, the calculated gravity field models of Amalthea can be a basis for further exploration of the Jupiter system. Furthermore, the model approach can be used for any planetary body.

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

    NASA Technical Reports Server (NTRS)

    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 < E < 4 keV neutrals from icy moon surfaces and 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

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

    NASA Technical Reports Server (NTRS)

    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 < E < 4 keV neutrals from icy moon surfaces and 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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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 foreseen for radar studies between 5MHz and 50MHz. While the high frequencies (above ˜40 MHz) are clean bands since natural jovian radio emissions show a high frequency cutoff at about 40 MHz, lower frequencies are right in the middle of the intense decametric (DAM) radio emissions. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are 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. One result from these simulations is that some portion of the orbit of Europa is clean from Non-Io DAM emissions above 22 MHz. We also review the radiation belts synchrotron emission characteristics. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation.

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

    NASA Astrophysics Data System (ADS)

    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.

    2011-10-01

    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 5MHz and 50MHz. 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 emission 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Breaking Ice 2: A rift system on the Ross Ice Shelf as an analog for tidal tectonics on icy moons

    NASA Astrophysics Data System (ADS)

    Brunt, K. M.; Hurford, T., Jr.; Schmerr, N. C.; Sauber, J. M.; MacAyeal, D. R.

    2016-12-01

    Ice shelves are the floating regions of the polar ice sheets. Outside of the influence of the narrow region of their grounding zone, they are fully hydrostatic and strongly influenced by the ocean tides. Recent observational and modeling studies have assessed the effect of tides on ice shelves, including: the tidal influence on the ice-shelf surface height, which changes by as much as 6 to 7 m on the southern extreme of the Ronne-Filchner Ice Shelf; the tidal modulation of the ice-shelf horizontal flow velocities, which changes the mean ice-flow rate by as much as two fold on the Ross Ice Shelf; and the tidal contribution to fracture and rift propagation, which eventually leads to iceberg calving. Here, we present the analysis of 16 days of continuous GPS data from a rift system near the front of the Ross Ice Shelf. While the GPS sites were installed for a different scientific investigation, and not optimized to assess tidal rifting mechanics, they provide a first-order sense of the tidal evolution of the rift system. These analyses can be used as a terrestrial analog for tidal activity on icy satellites, such as Europa and Enceladus, moons of Jupiter and Saturn, respectively. Using remote sensing and modeling of the Ross Ice Shelf rift system, we can investigate the geological processes observed on icy satellites and advance modeling efforts of their tidal-tectonic evolution.

  8. Jupiter

    NASA Astrophysics Data System (ADS)

    Simon, Seymour

    Describes the characteristics of the planet Jupiter and its moons as revealed by photographs sent back by two unmanned Voyager spaceships which took one-and-one half years to reach this distant giant.

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

    NASA Astrophysics Data System (ADS)

    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

  10. Mission Techniques for Exploring Saturn's icy moons Titan and Enceladus

    NASA Astrophysics Data System (ADS)

    Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

    2010-05-01

    The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiѐre hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit within NASA's New Frontiers or ESA's Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, several mission concepts have been developed that potentially fit within various cost classes. Also, a clear blueprint has been laid out for early efforts critical toward reducing the risks inherent in such missions. The purpose of this paper is to provide a brief overview of potential Titan (and Enceladus) mission

  11. Serpentinization-driven Hydrothermal Systems on Ocean Planets and Icy Moons

    NASA Astrophysics Data System (ADS)

    Harnmeijer, J.; Vance, S.

    2007-05-01

    The ferromagnesian silicate minerals olivine and clinopyroxene are dominant in planetary mantles, and similar assemblages likely also typify the subsurface lithologies of icy moons endowed with rocky interiors, such as Jupiter's Europa. Water is also common in the Solar System. Liquid water may persist to the present day on Mars, Europa, Callisto, Enceladus and Titan. Within the P-T window applicable to ocean/seafloor interaction (10-200 MPa, 273-700 K), the presence of water causes olivine and clinopyroxene to be unstable with respect to the serpentine minerals (antigorite, lizardite and chrysotile). The ensuing hydration reaction, termed 'serpentinization', essentially acts to re-equilibrate the nascent water-deficient high-temperature state that attended planetary formation to the water-saturated low- temperature state that characterizes the planetary seafloor environment. Importantly, thermodynamic considerations require that this process is accompanied by the release of both (i) heat energy resulting from the exothermic nature of the reaction; and (ii) H2 gas resulting from unlike FeMg-1 partitioning in the reactants and products of the reaction. Because of their potential to provide heat energy, nutrients and electron- donors for extraterrestrial metabolism in the absense of sunlight, and act as crucibles for Fischer-Tropsch-type (FTT-) synthesis of hydrocarbons, serpentinization-driven hydrothermal systems are of considerable interest to astrobiology. By assuming a bulk peridotitic composition and applying new insights on cracking depth, we constrain the potential heat- and H2 flux of extraterrestrial serpentinization over time. We further examine how different kinetic considerations affect the longevity of such systems. In the absence of crustal rejuvenation and under our assumed ideal conditions, serpentinization through progressive cracking persists on planetary timescales and generates heat on a globally averaged basis at a fraction of a percent of

  12. Applications of High Etendue Line-Profile Spectro-Polarimetry to the Study of the Atmospheric and Magnetospheric Environments of the Jovian Icy Moons

    NASA Technical Reports Server (NTRS)

    Harris, Walter M.; Roesler, Fred L.; Jaffel, Lotfi Ben; Ballester, Gilda E.; Oliversen, Ronald J.; Morgenthaler, Jeffrey P.; Mierkiewicz, Edwin

    2003-01-01

    Electrodynamic effects play a significant, global role in the state and energization of the Earth's ionosphere/magnetosphere, but even more so on Jupiter, where the auroral energy input is four orders of magnitude greater than on Earth. The Jovian magnetosphere is distinguished from Earth's by its rapid rotation rate and contributions from satellite atmospheres and internal plasma sources. The electrodynamic effects of these factors have a key role in the state and energization of the ionosphere-corona- plasmasphere system of the planet and its interaction with Io and the icy satellites. Several large scale interacting processes determine conditions near the icy moons beginning with their tenuous atmospheres produced from sputtering, evaporative, and tectonic/volcanic sources, extending out to exospheres that merge with ions and neutrals in the Jovian magnetosphere. This dynamic environment is dependent on a complex network of magnetospheric currents that act on global scales. Field aligned currents connect the satellites and the middle and tail magnetospheric regions to the Jupiter's poles via flux tubes that produce as bright auroral and satellite footprint emissions in the upper atmosphere. This large scale transfer of mass, momentum, and energy (e.g. waves, currents) means that a combination of complementary diagnostics of the plasma, neutral, and and field network must be obtained near simultaneously to correctly interpret the results. This presentation discusses the applicability of UV spatial heterodyne spectroscopy (SHS) to the broad study of this system on scales from satellite surfaces to Jupiter's aurora and corona.

  13. Physicochemical Requirements Inferred for Chemical Self-Organization Hardly Support an Emergence of Life in the Deep Oceans of Icy Moons.

    PubMed

    Pascal, Robert

    2016-05-01

    An approach to the origin of life, focused on the property of entities capable of reproducing themselves far from equilibrium, has been developed recently. Independently, the possibility of the emergence of life in the hydrothermal systems possibly present in the deep oceans below the frozen crust of some of the moons of Jupiter and Saturn has been raised. The present report is aimed at investigating the mutual compatibility of these alternative views. In this approach, the habitability concept deduced from the limits of life on Earth is considered to be inappropriate with regard to emerging life due to the requirement for an energy source of sufficient potential (equivalent to the potential of visible light). For these icy moons, no driving force would have been present to assist the process of emergence, which would then have had to rely exclusively on highly improbable events, thereby making the presence of life unlikely on these Solar System bodies, that is, unless additional processes are introduced for feeding chemical systems undergoing a transition toward life and the early living organisms. Icy moon-Bioenergetics-Chemical evolution-Habitability-Origin of life. Astrobiology 16, 328-334.

  14. The Extremes of Volcanic Activity: Earth and Jupiter's Moon Io

    NASA Astrophysics Data System (ADS)

    Lowes, L. L.; Lopes, R.

    2004-12-01

    Jupiter's moon Io is the solar system's most volcanically active body, and the only place that magmatic volcanic eruptions have been observed beyond Earth. One of the first images of Io obtained by NASA's Voyager 1 spacecraft in 1979 shows a plume above one of its volcanoes. The NASA Voyager and Galileo spacecraft imaged many explosive eruptions of plumes and deposits - which travel hundreds of kilometers (farther than on the Earth or the Moon). Very hot lavas that are erupting from volcanic vents on Io may be similar to lavas that erupted on Earth billions of years ago. Understanding the physical processes driving volcanic eruptions is important for the understanding of terrestrial volcanoes, not only because of their potential hazards, but also as geologic resources, biologic environments, and for their role in shaping the surface of Earth and other planets. Volcanic eruptions are perhaps the most dramatic events on Earth, and are of intrinsic interest to students, youth, and adults. Topics involving volcanoes are a part of the national science education benchmarks for understanding the Earth's composition and structure for grades 6-8 (the process of creating landforms) and grades 9-12 (the effects of movement of crustal plates). Natural events on Earth coupled with exciting discoveries in space can serve to heighten the awareness of these phenomena and provide learning opportunities for real world applications of science. Educational applications for youth to compare volcanic activity on Io and Earth have been done through NASA-sponsored field trip workshops to places such as Yellowstone National Park (allowing educators to experience environments similar to those on other worlds), targeted classroom and hands-on activities, special interest books, and other resources. A sampling of such activities will be presented, and discussion invited on other related developmentally appropriate resources and activities.

  15. Interactions Between Neutral Gas Clouds and Plasma Near the icy satellites of Jupiter and Saturn.

    NASA Astrophysics Data System (ADS)

    Burger, M. H.

    2007-05-01

    Neutral gas clouds associated with icy satellites are intimately tied to the magnetospheric plasma in which they are formed and reside. Plasma interactions can create the clouds, remove material from them, and make it possible for us to observe them. At Europa, for example, energetic ions incident on the icy surface eject hydrogen and oxygen formed from the dissociation of water (Johnson et al. 1982). The hydrogen escapes, but the O2remains gravitationally bound, forming an atmosphere. This atmosphere then interacts with the thermal plasma in Jupiter's magneotpshere: the O2is dissociated by the electrons resulting in emissions from atomic oxygen which have been observed by HST and Cassini (Hall et al. 1995; Hansen et al. 2005). Charge exchange with magnetospheric ions and electron-impact ionization removes atoms and molecules from Europa's atmosphere and exosphere, and contributes fresh ions to the plasma (Saur et al. 1998; Shematovich et al 2005). At Enceladus, where 150-300 kg/s of H2O gas is supplied by the south pole plume (Hansen et al. 2006; Burger et al. 2007), charge exchange reactions between the plasma and H2O produce fresh pickup ions which slow and deflect the plasma (Tokar et al. 2006; Pontius and Hill 2006) and induce perturbations in Saturn's magnetic field (Dougherty et al. 2006; Khurana et al. 2006). The neutrals created in these charge exchange reactions either escape from Saturn entirely or are redistributed throughout the inner magnetosphere forming gas clouds which have been observed by HST and Cassini (Johnson et al. 2006). I will describe the interaction processes between the neutral atoms and molecules in icy satellite atmospheres and exospheres, and discuss differences between the processes imporant in Jupiter's magnetosphere, where the plasma content is greater than the neutral content, and Saturn's magnetosphere, which is dominated by neutrals. References: Burger et al., JGR, 2007, in press. Dougherty et al., Science, 311, 1406, 2006

  16. Identifying new surface constituents of icy moons using mid-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    Spectroscopic compositional studies of the icy satellites can help us to better understand the formation and evolution of material in the outer solar system. The spectral complexity of the Saturnian satellite system as seen in reflected visible light suggests additional complexity may be present at mid-infrared wavelengths from which unique compositional information can be gleaned [1]. In addition, the mid-infrared is the region of the stronger fundamental diagnostic vibrational modes of many compounds. However, Cassini Composite Infrared Spectrometer (CIRS) surface compositional studies have received little attention to date.We are exploring the suitability of mid-infrared spectroscopy for discovering non-H2O compounds on icy moon surfaces. On the dark terrain of Iapetus, we find an emissivity feature at ~855 cm-1 and a potential doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts [2]. We attribute 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 [3]. Although silicates on the dark terrains of Saturn’s icy moons have been suspected for decades, there have been no definitive prior detections. Serpentines measured at ambient conditions have features near 855 cm-1 and 660 cm-1 [4]. However, peaks can shift depending on temperature, pressure, and grain size, so measurements at Iapetus-like conditions are necessary for more positive identifications [e.g., 5].We measured the vacuum, low temperature (125 K) spectra of various fine-grained powdered silicates. We find that some of these materials do have emissivity features near 855 cm-1 and match the doublet. Identifying a specific silicate would provide clues into the sources and sinks of the dark material in the Saturnian system. We report on our ongoing exploration of the CIRS icy moon dataset and plans for future measurements in JPL’s Icy Worlds Simulation Lab.[1] Flasar, F

  17. Discovering New Compounds on Icy Moon Surfaces with Mid-Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Young, C. L.; Wray, J. J.; Hand, K. P.; Poston, M.; Carlson, R. W.; Clark, R. N.; Spencer, J. R.; Jennings, D. E.

    2015-12-01

    Spectroscopy of icy satellite surfaces can aid us in understanding sources and sinks of material in the outer solar system. The spectral complexity of the Saturnian satellite system as seen in reflected sunlight suggests additional complexity may be present at mid-infrared wavelengths from which unique compositional information can be gleaned [1]. Yet to date, Cassini Composite Infrared Spectrometer (CIRS) surface compositional studies have received little attention. We are investigating the value of mid-infrared spectroscopy for identifying non-H2O constituents of icy moon surfaces. On Iapetus' dark terrain, we find an emissivity feature at ~855 cm-1 and a possible doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts [2]. We attribute the 855 cm-1feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths [3]. Silicates on the dark terrains of Saturn's icy moons have been suspected for decades, but there have been no definitive detections until now. Because peaks can shift depending on temperature, pressure, and grain size, measurements at Iapetus-like conditions are necessary for more positive feature identifications [e.g., 4]. We measured the vacuum (P<3x10-8 torr) and low temperature (125 K) mid-infrared spectra of various fine-grained powdered silicates. We find that some of these materials do have emissivity features near 855 cm-1and match the doublet. Identifying a specific silicate would provide clues into the origin and implications of the dark material in the Saturnian system. We also report on our ongoing exploration of the CIRS icy moon dataset and plans for additional future measurements in JPL's Icy Worlds Simulation Lab. [1] Flasar, F. M., et al. (2004), Space Sci Rev, 115, 169. [2] Young, C.L., et al. (in review), ApJ Lett. [3] Christensen, P. R., et al. (2004), Sci, 306, 1733. [4] Wray, J. J., et al. (2014), DPS 46th Meeting, Vol. 46.

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

    NASA Astrophysics Data System (ADS)

    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

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  1. Cassini Finds an Oxygen-Carbon Dioxide Atmosphere at Saturn’s Icy Moon Rhea

    NASA Astrophysics Data System (ADS)

    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.

    2010-12-01

    The flyby measurements of the Cassini spacecraft at Saturn’s moon Rhea reveal a tenuous oxygen (O2)-carbon dioxide (CO2) 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 O2 locked within Rhea’s ice. The presence of CO2 suggests radiolysis reactions between surface oxidants and organics or sputtering and/or outgassing of CO2 endogenic to Rhea’s ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism.

  2. Hemispheric and Topographic Asymmetry of Magnetospheric Particle Irradiation for Icy Moon Surfaces

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Sturner, S. J.

    2007-01-01

    All surfaces of icy moons without significant atmospheres, i.e. all except Titan in the giant planet systems, are irradiated by hot plasma and more energetic charged particles from the local magnetospheric environments. This irradiation can significantly impact the chemical composition, albedo, and detectable presence of signs of life on the sensible surfaces, while also limiting lifetimes and science operations of orbital spacecraft for extreme radiation environments as at Europa. Planning of surface remote sensing and lander operations, and interpretation of remote sensing and in-situ measurements, should include consideration of natural shielding afforded by the body of the moon, by any intrinsic or induced magnetic fields as at Ganyrnede, and by topographic structures.

  3. Photographer : JPL Callisto , The outermost Galilean Satellite , or Moon , of Jupiter, as taken by

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Callisto , The outermost Galilean Satellite , or Moon , of Jupiter, as taken by Voyager I . Range : About 7 Million km (5 Million miles) . Callisto, the darkest of the Galilean Satellites, still nearly twice as bright as the Earth's Moon, is seen here from the face that always faces Jupiter. All of the Galilean Satellites always show the same face to Jupiter, as the Earth's moon does to Earth. The Surface shows a mottled appearance of bright and dark patches. The former reminds scientists of rayed or bright haloed craters, similiar to those seen on earth's Moon. This color photo is assembled from 3 black and wite images taken though violet, orange, & green filters

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

    NASA Astrophysics Data System (ADS)

    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

  5. Miniaturized laser-induced plasma spectrometry for planetary in situ analysis - The case for Jupiter's moon Europa

    NASA Astrophysics Data System (ADS)

    Pavlov, S. G.; Jessberger, E. K.; Hübers, H.-W.; Schröder, S.; Rauschenbach, I.; Florek, S.; Neumann, J.; Henkel, H.; Klinkner, S.

    2011-08-01

    Jupiter's icy moon Europa is one of most promising places in our Solar System where possible extraterrestrial life forms could exist either in the past or even presently. The Europa Lander mission, an exciting part of the international Europa Jupiter System Mission (EJSM/Laplace), considers in situ planetary exploration of the moon. The distance of Europa from the Earth and the Sun asks for autonomous analytical tools that maximize the scientific return at minimal resources, demanding new experimental concepts. We propose a novel instrument, based on the atomic spectroscopy of laser generated plasmas for the elemental analysis of Europa's surface materials as far as it is in reach of the lander for example by a robotic arm or a mole, or just onboard the lander. The technique of laser-induced plasma spectrometry provides quantitative elemental analysis of all major and many trace elements. It is a fast technique, i.e. an analysis can be performed in a few seconds, which can be applied to many different types of material such as ice, dust or rocks and it does not require any sample preparation. The sensitivity is in the range of tens of ppm and high lateral resolution, down to 50 μm, is feasible. In addition, it provides the potential of depth profiling, up to 2 mm in rock material and up to a few cm in more transparent icy matrices. Key components of the instrument are presently developed in Germany for planetary in situ missions. This development program is accompanied by an in-depth methodical investigation of this technique under planetary environmental conditions.

  6. Stagnant lid convection in spherical shells: parameterizations and implications for icy moons

    NASA Astrophysics Data System (ADS)

    Yao, C.; Deschamps, F.; Tackley, P. J.; Sanchez Valle, C.

    2012-12-01

    The presence of subsurface oceans in large icy moons has gained increasing support during the past decade, both from theoretical studies and from spacecraft missions measurements (e.g., magnetic data). The exact thickness of subsurface ocean, if present, depends on the detailed thermal evolution of each moon, and on its primordial composition. It has been shown that the presence of volatiles (including ammonia and methanol) in small volume fraction strongly opposes the cristallization of the primordial ocean. Also crucial is the heat transfer through the outer ice I layer, which controls the cooling of the satelitte interior. Convection is likely the most efficient way to transfer heat through this layer, but the regime of convection (and therefore the heat transfer) depends on the rheology of the fluid. In the case of ice, viscosity is strongly temperature dependent and thermal convection in the outer ice shell follows a stagnant lid regime: a stagnant lid forms at the top of the system, and convection is confined in a sublayer. Previous numerical studies including strongly temperature-dependent viscosities have already been performed in 2D Cartesian geometry allowing the determination of scaling laws relating the mean temperature and heat flux to the vigor of convection (described by the Rayleigh number) and the ratio of the top to the bottom viscosity, but 3D spherical geometry may provide a more accurate description of convection within the outer ice layer of icy moons. In this work, we model the heat transfer in spherical shells for a strongly temperature-dependent viscosity fluid heated from below. We use StagYY to run simulations for different ratios of the inner to outer radii of the ice layer (f), Rayleigh number (Ra), and thermal viscosity contrast (Δη). The inversion of the results of more than 30 numerical experiments allows the determination of scaling laws for the temperature of the well-mixed interior and surface heat flux. In particular, we find

  7. MAJIS (Moons and Jupiter Imaging Spectrometer): the VIS-NIR imaging spectrometer of the JUICE mission

    NASA Astrophysics Data System (ADS)

    Langevin, Yves; Piccioni, Giuseppe; Dumesnil, Cydalise; Filacchione, Gianrico; Poulet, Francois; MAJIS Team

    2016-10-01

    MAJIS is the VIS-NIR imaging spectrometer of JUICE. This ambitious mission of ESA's « cosmic vision » program will investigate Jupiter and its system with a specific focus on Ganymede. After a tour of more than 3 years including 2 fly-bys of Europa and up to 20 flybys of Ganymede and Callisto, the end of the nominal mission will be dedicated to an orbital phase around Ganymede with 120 days in a near-circular, near-polar orbit at an altitude of 5000 km and 130 days in a circular near-polar orbit at an altitude of 500 km. MAJIS will adress 17 of the 19 primary science objectives of JUICE, investigating the surface and exosphere of the Galilean satellites (Ganymede during the orbital phase, Europa and Callisto during close flybys, Io from a minimum distance of 570,000 km), the atmosphere / exosphere of Jupiter, small satellites and rings, and their role as sources and sinks of particles in the Jupiter magnetosphere.The main technical characteristics are the following:Spectral range : 0.5 - 5.7 µm with two overlapping channels (VIS-NIR : 0.5 - 2.35 µm ; IR : 2.25 - 5.7 µm)Spatial resolution : 0.125 to 0.15 mradSpectral sampling (VIS-NIR channel) : 2.9 to 3.45 nmSpectral sampling (IR channel) : 5.4 to 6.45 nmThe spectral and spatial resolution will be finalized in october 2016 after the selection of the MAJIS detectors.Passive cooling will provide operating temperatures < 130 K (VIS-NIR) and < 90 K (IR) so as to limit the impact of dark current on performances.The SNR as determined from the photometric model and the noise model will be larger than 100 over most of the spectral range except for high resolution observations of icy moons at low altitude due to limitations on the integration time even with motion compensation provided by a scanner and for exospheric observations due to intrinsic low signal levels.

  8. Carbonic acid as a reserve of carbon dioxide on icy moons: The formation of carbon dioxide (CO{sub 2}) in a polar environment

    SciTech Connect

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-06-20

    Carbon dioxide (CO{sub 2}) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ν{sub 3} band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO{sub 2} band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H{sub 2}O)-carbon dioxide (CO{sub 2}) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ν{sub 3} band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Choblet, Gael; Tobie, Gabriel; Sotin, Christophe; Kalousova, Klara; Grasset, Olivier

    2017-04-01

    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

  11. The H2O-MGSO4 System and the Perspective of Deep Oceans for Large Icy Moons

    NASA Astrophysics Data System (ADS)

    Bollengier, O.; Grasset, O.; Le Menn, E.; Tobie, G.

    2014-02-01

    We conducted new experiments in the H2O-MgSO4 system to explore the liquidus of H2O ice phases over the 0 - 1 GPa pressure range. These results bring new constraints on the formation and stability of deep oceans in large icy moons.

  12. Radiolytic Production of Carbonic Acid and Applications to Jupiter's Icy Satellites

    NASA Astrophysics Data System (ADS)

    Carlson, R. W.; Hand, K. P.; Gerakines, P. A.; Moore, M. H.; Hudson, R. L.

    2005-08-01

    Europa, Ganymede, and Callisto all exhibit surficial CO2 and these satellites are heavily bombarded by energetic magnetospheric particles and solar ultraviolet radiation. Irradiation of CO2 in water ice produces carbonic acid, H2CO3 and it has been suggested that the 3.8-micron features in NIMS spectra of Ganymede and Callisto arise from H2CO3 (Hage et al., Science 279, 1332-1335, 1998). We combine results from proton- and ultraviolet-irradiated H2O:CO2 ices with recent electron irradiation results to investigate this possibility. Carbonic acid production efficiencies, per 100 eV and at the same experimental conditions (H2O:CO2 = 1:1, 20 K), are G = 0.028 ± 0.024 and 0.030 ± 0.016 for proton and ultraviolet irradiation, respectively, whereas our provisional value for 10-keV electron irradiation is G = 0.011. Additionally, we provided sufficient electron dose to form equilibrium concentrations, where the rate of H2CO3 destruction equals the formation rate. The effective destruction cross section is about 4 x 10-17 cm2 and the equilibrium molar concentration ratio is [H2CO3]/[CO2] = 0.01. At equilibrium, the ratio of the equivalent widths of the H2CO3 3.8-micron and CO2 4.3-micron bands is about 0.07 and consistent with the observed ratio of 0.11 in Callisto spectra. The band positions of this feature in laboratory and Callisto spectra, 3.86 and 3.87 microns, respectively, are also in good agreement. Carbonic acid is a plausible candidate on the surfaces of Jupiter's icy satellites. This work was supported by NASA's Planetary Geology and Geophysics and Exobiology Programs.

  13. Tectonics of Icy Moons: A Tale of Oceans and Orbital Dynamics

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon

    2010-05-01

    Icy moons of the outer solar system commonly experience eccentric orbits that impart daily tidal stresses to the outer ice layer. Depending on the orbital dynamics and configuration of the moons and their host planets, these stresses may or may not be sufficiently large to deform the ice layer. Although the stresses are typically very small, many icy moons exhibit pervasively tectonized surfaces, replete with fractures, faults, and significant topography (e.g., Europa, Ganymede, Enceladus, Dione, Titan, Miranda, Ariel, Titania, Triton). Deformation may be driven by various means (e.g., orbital recession, polar wander, ice shell thickening), but tidal deformation is particularly important and is enhanced if an outer ice layer is decoupled from an underlying liquid ocean. The tidal response of the ocean creates tidal bulges in the ice layer that oscillate longitudinally and in amplitude during the orbital period. The resultant diurnal tidal stress field (perhaps 10s of kPa) rotates throughout the orbit. Any fractures growing in this time frame should thus be curved (e.g., Europa's cycloidal cracks, which have been cited as the smoking gun for a subsurface ocean). Long lineaments should accumulate strike-slip offsets in such a stress field, as occurs on Europa and perhaps Enceladus. The progressive development of ice ridges to either side of central cracks may result from this shearing process. A decoupled ice layer also permits faster than synchronous rotation of the ice layer, which may allow several MPa of stress to accrue, perhaps explaining long lineaments on Europa. It is unclear if Europa continues to be tectonically active, especially given apparent ice shell thickening that would have muted the tidal response through time. Nonetheless, subtle troughs across Europa's surface crosscut all other features and may indicate some degree of ongoing activity. In contrast, active tectonics on Enceladus is implied by ongoing geyser-like eruptions of water-ice from

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

    NASA Astrophysics Data System (ADS)

    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

  15. Resonance locking as the source of rapid tidal migration in the Jupiter and Saturn moon systems

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Luan, Jing; Quataert, Eliot

    2016-06-01

    The inner moons of Jupiter and Saturn migrate outwards due to tidal energy dissipation within the planets, the details of which remain poorly understood. We demonstrate that resonance locking between moons and internal oscillation modes of the planet can produce rapid tidal migration. Resonance locking arises due to the internal structural evolution of the planet and typically produces an outward migration rate comparable to the age of the Solar system. Resonance locking predicts a similar migration time-scale but a different effective tidal quality factor Q governing the migration of each moon. The theory also predicts nearly constant migration time-scales a function of semimajor axis, such that effective Q values were larger in the past. Recent measurements of Jupiter and Saturn's moon systems find effective Q values that are smaller than expected (and are different between moons), and which correspond to migration time-scales of ˜10 Gyr. If confirmed, the measurements are broadly consistent with resonance locking as the dominant source of tidal dissipation in Jupiter and Saturn. Resonance locking also provides solutions to several problems posed by current measurements: it naturally explains the exceptionally small Q governing Rhea's migration, it allows the large heating rate of Enceladus to be achieved in an equilibrium eccentricity configuration, and it resolves evolutionary problems arising from present-day migration/heating rates.

  16. Resonance locking as the source of rapid tidal migration in the Jupiter and Saturn moon systems

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Luan, Jing; Quataert, Eliot

    2016-10-01

    The inner moons of Jupiter and Saturn migrate outwards due to tidal energy dissipation within the planets, the details of which remain poorly understood. We demonstrate that resonance locking between moons and internal oscillations of the planet can produce rapid tidal migration. Resonance locking arises due to the structural evolution of the planet and typically produces an outward migration rate comparable to the age of the solar system. Resonance locking predicts a similar migration timescale but a different effective tidal quality factor Q governing the migration of each moon. It also predicts nearly constant migration timescales a function of semi-major axis, such that effective Q values were larger in the past. Recent measurements of Jupiter and Saturn's moon systems find effective Q values that are much smaller than expected (and are different between moons), and which correspond to migration timescales of ~10 Gyr. If confirmed, the measurements are broadly consistent with resonance locking as the dominant source of tidal dissipation in Jupiter and Saturn. Resonance locking also provides solutions to several problems posed by current measurements: it naturally explains the exceptionally small Q governing Rhea's migration, it allows the large heating rate of Enceladus to be achieved in an equilibrium eccentricity configuration, and it resolves evolutionary problems arising from present-day migration/heating rates.

  17. Laboratory Infrared Spectroscopy to Identify New Compounds on Icy Moon Surfaces

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    We are exploring the value of mid-infrared spectroscopy for identifying non-H2O constituents of icy moon surfaces. Recently we reported evidence for a new emissivity feature identified on Iapetus using Cassini’s Composite Infrared Spectrometer [1]. This 11.7 μm feature is consistent with emissivity minima (transparency features) of very fine-grained silicates. Its position and shape may be diagnostic of silicate type, but most lab data at these wavelengths have been acquired using coarser grains and/or at Earth surface pressures and temperatures. Infrared spectra can change substantially under low-temperature, vacuum conditions [e.g., 2,3].We prepared sieved (<0.4 mm) and very fine-grained (few μm) powders of six different silicates and measured their VNIR (0.35-2.5 μm) reflectance spectra under ambient air, and mid-IR (1.2-20 μm) spectra in a purged N2 glovebox. All silicates exhibited mid-IR transparency features (and loss of other features) in micronized form that were not observed for the coarser grain sizes. Muscovite, a phyllosilicate mineral possibly similar to those tentatively identified on Europa [4], provided the closest match to Iapetus in the mid-IR--although clear VNIR features of muscovite have not been identified on Iapetus [5]--and therefore we measured muscovite across the same wavelength range under Iapetus-like conditions (T=125 K, P<3x10^-8 torr). We will report on our ongoing analysis and plans for additional future measurements in JPL’s Icy Worlds Simulation Lab. [1] Young, C.L., et al. (2014), Workshop on the Habitability of Icy Worlds, Abstract #4038.[2] Logan, L.M., et al. (1973), J. Geophys. Res., 78(23), 4983-5003.[3] Donaldson Hanna, K.L., et al. (2012), J. Geophys. Res., 117, E00H05.[4] Shirley, J.H., et al. (2013), AGU Fall Meeting, Abstract #P54A-07.[5] Clark, R.N., et al. (2012), Icarus, 218, 831-860.

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

    NASA Astrophysics Data System (ADS)

    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

  19. Dielectric characterization of ice/MgSO4ṡ11H2O mixtures as Jovian icy moon crust analogues

    NASA Astrophysics Data System (ADS)

    Pettinelli, Elena; Lauro, Sebastian Emanuel; Cosciotti, Barbara; Mattei, Elisabetta; Di Paolo, Federico; Vannaroni, Giuliano

    2016-04-01

    One of the main objectives of proposed missions to the icy Jovian moons is to prove the existence of the postulated subsurface ocean on Europa using radar sounders. The success of these missions will rely on the ability of the radar signals to penetrate ten kilometers of icy material that could potentially contain various types of impurities. In this work we quantify the impact of magnesium sulfate hydrates on the electrical properties of water ice by performing a series of dielectric measurements on different ice/MgSO4ṡ11H2O mixtures as a function of frequency and at temperatures comparable with those expected on the icy satellite surfaces. Our results indicate that the salt only affects the real part of permittivity of the mixtures, whereas the imaginary part, hence the attenuation, does not significantly differ from that of pure ice. This means that in some regions signal penetration may be better than previously thought.

  20. Physicochemical Requirements Inferred for Chemical Self-Organization Hardly Support an Emergence of Life in the Deep Oceans of Icy Moons

    NASA Astrophysics Data System (ADS)

    Pascal, Robert

    2016-05-01

    An approach to the origin of life, focused on the property of entities capable of reproducing themselves far from equilibrium, has been developed recently. Independently, the possibility of the emergence of life in the hydrothermal systems possibly present in the deep oceans below the frozen crust of some of the moons of Jupiter and Saturn has been raised. The present report is aimed at investigating the mutual compatibility of these alternative views. In this approach, the habitability concept deduced from the limits of life on Earth is considered to be inappropriate with regard to emerging life due to the requirement for an energy source of sufficient potential (equivalent to the potential of visible light). For these icy moons, no driving force would have been present to assist the process of emergence, which would then have had to rely exclusively on highly improbable events, thereby making the presence of life unlikely on these Solar System bodies, that is, unless additional processes are introduced for feeding chemical systems undergoing a transition toward life and the early living organisms.

  1. Galileo to Jupiter: Probing the Planet and Mapping Its Moons

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The first project to use the space shuttle as an interplanetary launch vehicle, the Galileo mission is designed to obtain information about the origin and evolution of the solar system by studying large-scale phenomena on Jupiter and its satellites. Aimed towards Mars to obtain gravity assist, the orbiting spacecraft will deploy a probe, which penetrating the Jovian atmosphere, will transmit data for approximately an hour. The spacecraft itself will inspect the atmospheres, ionospheres, and surfaces of Ganymede, Io, Europa, and Callisto, as well as determine their magnetic and gravitational properties. The experiments to be conducted and their scientific objectives are described. Known facts about the Jovian system are reviewed.

  2. Clump detections and limits on moons in Jupiter's ring system.

    PubMed

    Showalter, Mark R; Cheng, Andrew F; Weaver, Harold A; Stern, S Alan; Spencer, John R; Throop, Henry B; Birath, Emma M; Rose, Debi; Moore, Jeffrey M

    2007-10-12

    The dusty jovian ring system must be replenished continuously from embedded source bodies. The New Horizons spacecraft has performed a comprehensive search for kilometer-sized moons within the system, which might have revealed the larger members of this population. No new moons were found, however, indicating a sharp cutoff in the population of jovian bodies smaller than 8-kilometer-radius Adrastea. However, the search revealed two families of clumps in the main ring: one close pair and one cluster of three to five. All orbit within a brighter ringlet just interior to Adrastea. Their properties are very different from those of the few other clumpy rings known; the origin and nonrandom distribution of these features remain unexplained, but resonant confinement by Metis may play a role.

  3. Icy Profile

    NASA Image and Video Library

    2008-10-20

    The Cassini spacecraft looks toward Rhea cratered, icy landscape with the dark line of Saturn ringplane and the planet murky atmosphere as a background. Rhea is Saturn second-largest moon, at 1,528 kilometers 949 miles across.

  4. Derivation of the collision probability between orbiting objects The lifetimes of Jupiter's outer moons

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.

    1981-01-01

    A general form is derived for Opik's equations relating to the probability of collision between two orbiting objects to their orbital elements, and used to determine the collisional lifetime of the eight outer moons of Jupiter. The derivation is based on a concept of spatial density, or average number of objects found in a unit volume, and results in a set of equations that are easily applied to a variety of orbital collision problems. When applied to the outer satellites, which are all in irregular orbits, the equations predict a relatively long collisional lifetime for the four retrograde moons (about 270 billon years on the average) and a shorter time for the four posigrade moons (0.9 billion years). This short time is suggestive of a past collision history, and may account for the orbiting dust detected by Pioneers 10 and 11.

  5. Tidal reorientation and the fracturing of Jupiter's moon Europa

    USGS Publications Warehouse

    McEwen, A.S.

    1986-01-01

    The most striking characteristic of Europa is the network of long linear albedo markings over the surface, suggestive of global-scale tectonic processes. Various explanations for the fractures have been proposed: Freezing and expansion of an early liquid water ocean1, planetary expansion due to dehydration of hydrated silicates2, localization by weak points in the crust generated by impacts3, and a combination of stresses due to planetary volume change and tidal distortions from orbital recession and orbital eccentricity4,5. Calculations by Yoder6 and Greenberg and Weidenschilling7 have shown that Europa may rotate slightly more rapidly than the synchronous rate, with a rotation period (reorientation through 360??) ranging from 20 to >103 yr if a liquid mantle is present, or up to 1010 yr if the satellite is essentially solid7. Helfen-stein and Parmentier8 modelled the stresses due to nonsynchronous rotation, and concluded that this could explain the long fractures in part of the anti-jovian hemisphere. In this note, I present a global map of lineaments with long arc lengths (>20?? or 550 km), and compare the lineament orientations to the tensile stress trajectories due to tidal distortions (changes in the lengths of three principal semiaxes) and to nonsynchronous rotation (longitudinal reorientation of two of the principal semiaxes). An excellent orthogonal fit to the lineaments is achieved by the stresses due to nonsynchronous rotation with the axis radial to Jupiter located 25?? east of its present position. This fit suggests that nonsynchronous rotation occurred at some time in Europa's history. ?? 1986 Nature Publishing Group.

  6. Deconvolution of IRTF Observations of Jupiter's Moon Io

    NASA Astrophysics Data System (ADS)

    Wernher, Hannah; Rathbun, Julie A.; Spencer, John R.

    2016-10-01

    Io is a active volcanic world with a heat output more than 40 times that of earth. While spacecraft have been used to study Io's volcanoes, their high level of variability requires Earth-based observations to reveal their eruptions in the absence of spacecraft data. Our nearly 20 years of observations from the NASA InfraRed Telescope Facility (IRTF) have been used to monitor volcanic eruptions on Io. Our observations allow us not only to better understand the eruption properties of Ionian volcanoes, but also how the volcanic eruptions affect the rest of the Jovian system, such as the Io plasma torus, sodium clouds, Jovian magnetosphere, and aurorae. While our Jupiter occultation lightcurves of an eclipsed Io have been the focus of this program, due to their ability to determine volcano brightnesses and 1D locations, those observations only allow us to measure volcanic eruptions on the sub-Jovian hemisphere. We also observe Io in reflected sunlight so that we can observe other longitudes on Io. But, brighter eruptions are required for us to be able to distinguish them above the reflected sunlight. We are able to increase the spatial resolution of these images of in order to detect and locate fainter hotspots. We have employed shift-and-add techniques using multiple short exposures to detect eruptions in the past (Rathbun and Spencer, 2010). We will report on the use of publically available deconvolution algorithms to further improve spatial resolution and hot spot detectability, using images of a standard star as our PSF, including experiments with performing the deconvolution both before and after shift and add. We will present results of observations from 2007 and 2013.

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

    NASA Technical Reports Server (NTRS)

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

    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.

  8. Tidal Dissipation Within the Jupiter Moon Io - A Numerical Approach

    NASA Astrophysics Data System (ADS)

    Steinke, Teresa; van der Wal, Wouter; Hu, Haiyang; Vermeersen, Bert

    2017-04-01

    Satellite images and recent Earth-based observations of the innermost of the Galilean moons reveal a conspicuous pattern of volcanic hotspots and paterae on its surface. This pattern is associated with the heat flux originating from tidal dissipation in Io's mantle and asthenosphere. As shown by many analytical studies [e.g. Segatz et al. 1988], the local heat flux pattern depends on the rheology and structure of the satellite's interior and therefore could reveal constraints on Io's present interior. However, non-linear processes, different rheologies, and in particular lateral variations arising from the spatial heating pattern are difficult to incorporate in analytical 1D models but might be crucial. This motivates the development of a 3D finite element model of a layered body disturbed by a tidal potential. As a first step of this project we present a 3D finite element model of a spherically stratified body of linear viscoelastic rheology. For validation, we compare the resulting tidal deformation and local heating patterns with the results obtained by analytical models. Numerical errors increase with lower values of the asthenosphere viscosity. Currently, the numerical model allows realistic simulation down to viscosities of 1018 Pa s. Furthermore, we investigate an adequate way to deal with the relaxation of false modes that arise at the onset of the periodic tidal potential series in the numerical approach. Segatz, M., Spohn, T., Ross, M. N., Schubert, G. (1988). Tidal dissipation, surface heat flow, and figure of viscoelastic models of Io. Icarus, 75(2), 187-206.

  9. Development and Testing of a Laser-Powered Cryobot for Outer Planet Icy Moon Exploration

    NASA Astrophysics Data System (ADS)

    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

  10. 3GM: Gravity and Geophysics of Jupiter and the Galilean Moons

    NASA Astrophysics Data System (ADS)

    Iess, L.

    2013-09-01

    3GM (Gravity and Geophysics of Jupiter and the Galilean Moons) addresses JUICE scientific goals pertaining to gravity, geophysics and atmospheric science with radio occultations. The 3GM payload comprises two elements, namely a high performance Ka-band transponder (KaT) and an ultra-stable oscillator (USO). Thanks to the adoption of an advanced microwave tracking system, the gravity fields of Ganymede, Callisto and Europa will be determined to the best accuracy allowed by the spacecraft design and mission profile. Probing of Jupiter's atmosphere will be enhanced by the use of two frequencies (8.4 and 32.5 GHz) and by the proposed onboard recording of the uplink signal.

  11. Volcanism on Jupiter's moon Io and its relation to interior processes

    NASA Astrophysics Data System (ADS)

    Hamilton, Christopher

    2013-04-01

    Jupiter's moon Io is the most volcanically active body in the Solar System and offers insight into processes of tidal heating, melt generation, and magma ascent. Investigating these processes contributes to a better understanding of Io's geologic history, internal structure, and tidal dissipation mechanisms, as well as to understanding similar processes operating on other tidally-heated worlds (e.g., Europa, Enceladus, and some exoplanets). Four recent developments provide new observational constraints that prompt re-examination of the relationships between Io's surficial geology and interior structure. These developments include: (1) completion of the first 1:15,000,000 scale geologic map of Io based on a synthesis of Voyager and Galileo data; (2) re-interpretation of Galileo magnetometer data, which suggests that Io has a globally continuous subsurface magma ocean; (3) new global surveys of the power output from volcanic centers on Io; and (4) identification of an offset between volcano concentrations and surface heat flux maxima predicted by solid body tidal heating models. In this study, the spatial distributions of volcanic hotspots and paterae on Io are characterized using distance-based clustering techniques and nearest neighbor statistics. Distance-based clustering results support a dominant role for asthenospheric heating within Io, but show a 30-60° eastward offset in volcano concentrations relative to locations of predicted surface heat flux maxima. The observed asymmetry in volcano concentrations, with respect to the tidal axis, cannot be explained by existing solid body tidal heating models. However, identification of a global magma ocean within Io raises the intriguing possibility that a fluid tidal response—analogous to the heating of icy satellites by fluid tidal dissipation in their liquid oceans—may modify Io's thermal budget and locations of enhanced volcanism. The population density of volcanoes is greatest near the equator, which also

  12. Shock vaporization and the accretion of the icy satellites of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Ahrens, T. J.; Okeefe, J. D.

    1985-01-01

    The known properties of water and ice over a wide range of pressures and temperatures are applied to describe constraints on the shock vaporization processes for water and ice in the solar system. In particular, the role of impact vaporization acting during the formation of the Jovian and Saturnian satellites is examined in an attempt to explain the observed density in terms of composition of these rock and ice objects. A possible model of accretion of icy satellites is considered which predicts that the amount of ice devolatilization is related to planetary size.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. The H_2O and O_2 exospheres of Jupiter's moon Ganymede.

    NASA Astrophysics Data System (ADS)

    Plainaki, C.; Milillo, A.; Massetti, S.; Mura, A.; Jia, X.; Orsini, S.; Mangano, V.; De Angelis, E.; Lazzarotto, F.; Rispoli, R.

    A simulation of the H_2O and O_2 exospheres of Jupiter' moon Ganymede, through the application of a 3D Monte Carlo modeling technique, is presented. Our model takes into consideration the combined effect on the exosphere generation of the main surface release processes (i.e. sputtering, sublimation and radiolysis) and the surface precipitation of the energetic ions of Jupiter's magnetosphere constrained strongly by Ganymede's intrinsic magnetic field. In order to model the magnetospheric ion precipitation to Ganymede's surface, we used as an input the electric and magnetic fields from the global MHD model of Ganymede's magnetosphere (Jia et al., 2009). The exospheric model described in this paper is based on EGEON, a single-particle Monte Carlo model already applied for a Galilean satellite \\citep{PC10,PC12,PC13}. We find that at small altitudes above the moon.s subsolar point the main contribution to the neutral environment comes from sublimated H_2O whereas the spatial distribution of the directly sputtered-H_2O molecules exhibits a close correspondence with the plasma precipitation region and extends at high altitudes, being, therefore, well differentiated from the sublimated water. Moreover, we find that the O_2 exosphere comprises two different regions: the first one is an homogeneous, relatively dense, thermal-O_2 region extending to some 100s of km above the surface, whereas the second one is less homogeneous and consists of more energetic O_2 molecules sputtered directly from the surface after water-dissociation by ions has taken place; the spatial distribution of the energetic surface-released O_2 molecules depends both on the impacting plasma properties and the moon's surface temperature distribution.

  15. Gravity field of Jupiter's moon Amalthea and the implication on a spacecraft trajectory

    NASA Astrophysics Data System (ADS)

    Weinwurm, G.; Weber, R.

    Before its final plunge into Jupiter in September 2003, GALILEO made a last 'visit' to one of Jupiter's moons - Amalthea. This final flyby of the spacecraft's successful mission occurred on November 5, 2002. In order to analyse the spacecraft data with respect to Amalthea's gravity field, interior models of the moon had to be provided. The method used for this approach is based on the numerical integration of infinitesimal volume elements, which are calculated by the scale factors of a three-axial ellipsoid (elliptic coordinates). Within this routine the shape information of Amalthea can be included as well. To derive the gravity field coefficients of the body, the second method of Neumann was applied. Based on the spacecraft trajectory data provided by the Jet Propulsion Laboratory, GALILEO's velocity perturbations at closest approach could be calculated. We have derived the harmonic coefficients of Amalthea's gravity field up to degree and order six, for both homogeneous and reasonable heterogeneous cases. Founded on these numbers we calculated the impact on the trajectory of GALILEO, compared it to existing Doppler data and made predictions for future spacecraft flybys. Although no two-way Doppler-data was available during the flyby and the harmonic coefficients of the gravity field are buried in the one-way Doppler-noise, the gravity field models of Amalthea show the possible interior structure of the moon and can be a basis for further exploration of the Jovian system. In order to get valuable information about the gravity field of this tiny rocky moon, a much closer flyby than that of GALILEO should be anticipated. The above stated model approach can be used for any planetary body.

  16. Jupiter

    NASA Astrophysics Data System (ADS)

    Bagenal, Fran; Dowling, Timothy E.; McKinnon, William B.

    2007-03-01

    Preface; 1. Introduction F. Bagenal, T. E. Dowling and W. B. McKinnon; 2. The origin of Jupiter J. I. Lunine, A. Corandini, D. Gautier, T. C. Owen and G. Wuchterl; 3. The interior of Jupiter T. Guillot, D. J. Stevenson, W. B. Hubbard and D. Saumon; 4. The composition of the atmosphere of Jupiter F. W. Taylor, S. K. Atreya, Th. Encrenaz, D. M. Hunten, P. G. J. Irwin and T. C. Owen; 5. Jovian clouds and haze R. A. West, K. H. Baines, A. J. Friedson, D. Banfield, B. Ragent and F. W. Taylor; 6. Dynamics of Jupiter's atmosphere A. P. Ingersoll, T. E. Dowling, P. J. Gierasch, G. S. Orton, P. L. Read, A. Sánchez-Lavega, A. P. Showman, A. A. Simon-Miller and A. R. Vasavada; 7. The stratosphere of Jupiter J. I. Moses, T. Fouchet, R. V. Yelle, A. J. Friedson, G. S. Orton, B. Bézard, P. Drossart, G. R. Gladstone, T. Kostiuk and T. A. Livengood; 8. Lessons from Shoemaker-Levy 9 about Jupiter and planetary impacts J. Harrington, I. de Pater, S. H. Brecht, D. Deming, V. Meadows, K. Zahnle and P. D. Nicholson; 9. Jupiter's thermosphere and ionosphere R. V. Yelle and S. Miller; 10. Jovian dust: streams, clouds and rings H. Krüger, M. Horányi, A. V. Krivov and A. L. Graps; 11. Jupiter's ring-moon system J. A. Burns, D. P. Simonelli, M. R. Showalter, D. P. Hamilton, C. C. Porco, H. Throop and L. W. Esposito; 12. Jupiter's outer satellites and trojans D. C. Jewitt, S. Sheppard and C. Porco; 13. Interior composition, structure and dynamics of the Galilean satellites G. Schubert, J. D. Anderson, T. Spohn and W. B. McKinnon; 14. The lithosphere and surface of Io A. S. McEwen, L. P. Keszthelyi, R. Lopes, P. M. Schenk and J. R. Spencer; 15. Geology of Europa R. Greeley, C. F. Chyba, J. W. Head III, T. B. McCord, W. B. McKinnon, R. T. Pappalardo and P. Figueredo; 16. Geology of Ganymede R. T. Pappalardo, G. C. Collins, J. W. Head III, P. Helfenstein, T. B. McCord, J. M. Moore, L. M. Procktor, P. M. Shenk and J. R. Spencer; 17. Callisto J. M. Moore, C. R. Chapman. E. B. Bierhaus, R

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    The Galilean moons reveal large albedo variations on their surfaces, in particular between their leading and trailing hemispheres. The differences observed are likely the results of a balance between various weathering processes of the surface, determined by the moons' local environment. Chemical and physical alterations occur at the surface, triggered by multiple exogenic energy deposit processes (radiolysis, plasma sputtering, micro-meteoroids impacts, …).The observed variations are probably due to anisotropy in the energy fluxes received on each hemisphere and due to to a different relative contribution of the weathering agents (plasma, dust…) as function of the distance to Jupiter. We will be testing this hypothesis by estimating quantitatively the kinetic energy flux impacting different part of the surfaces of the Galilean moons. This work is essential in the context of the future missions to the Jovian moons, such as the JUICE ESA mission, as a proper understanding of the moons' surface history can be achieved only if one is able to constrain the balance between exogenic and endogenic alteration processes.Impacts of dust particles coming from the Galilean moons and evolving dynamically in the Jovian system will be simulated using the Jovian Micrometeoroid Environment Model (JMEM) [1]. Direct interplanetary dust impacts are simulated using the prediction of the Interplanetary Micrometeoroid Environment Model (IMEM) [2] computed at Jupiter's Hill radius, taking into account gravitational focusing by the planet. Finally, electron and ion fluxes interacting with different parts of the moons' surfaces can be estimated using the Jovian Specification Environment model (JOSE) [3].In parallel, signature of surface weathering will be assessed using reflectance maps based on the Galileo imaging data.Those models will also be applied, for comparison, to other atmosphere-less bodies of the solar system such as the asteroids Ceres, Vesta and Pallas.References[1] Liu et

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    This poster introduces a thermo-chemical ice penetrator for Ocean Worlds. It employs a eutectic mix of alkali metals that produce an exothermic with an icy surface. This technology builds on successful classified 1980's era program for the US Navy.

  19. High-powered Radar Sounders for the Investigation of Jupiter's Icy Moons

    NASA Technical Reports Server (NTRS)

    Safaeinili, A.; Rodriguez, E.; Edelstein, Wendy

    2003-01-01

    This talk will address the main drivers in the design of a radar sounder for the JIMO mission and provide a potential solution that will optimize the chances of success in the detection of ice/water interface and sub-surface stratigraphy.

  20. A disk of scattered icy objects and the origin of Jupiter-family comets.

    PubMed

    Duncan, M J; Levison, H F

    1997-06-13

    Orbital integrations carried out for 4 billion years produced a disk of scattered objects beyond the orbit of Neptune. Objects in this disk can be distinguished from Kuiper belt objects by a greater range of eccentricities and inclinations. This disk was formed in the simulations by encounters with Neptune during the early evolution of the outer solar system. After particles first encountered Neptune, the simulations show that about 1 percent of the particles survive in this disk for the age of the solar system. A disk currently containing as few as approximately 6 x 10(8) objects could supply all of the observed Jupiter-family comets. Two recently discovered objects, 1996 RQ20 and 1996 TL66, have orbital elements similar to those predicted for objects in this disk, suggesting that they are thus far the only members of this disk to be identified.

  1. Experimental investigation of the radiation shielding efficiency of a MCP detector in the radiation environment near Jupiter's moon Europa

    NASA Astrophysics Data System (ADS)

    Tulej, M.; Meyer, S.; Lüthi, M.; Lasi, D.; Galli, A.; Piazza, D.; Desorgher, L.; Reggiani, D.; Hajdas, W.; Karlsson, S.; Kalla, L.; Wurz, P.

    2016-09-01

    Neutral Ion Mass spectrometer (NIM) is one of the instruments in the Particle Environmental Package (PEP) designed for the JUICE mission of ESA to the Jupiter system. NIM, equipped with a sensitive MCP ion detector, will conduct detailed measurements of the chemical composition of Jovian icy moons exospheres. To achieve high sensitivity of the instrument, radiation effects due to the high radiation background (high-energy electrons and protons) around Jupiter have to be minimised. We investigate the performance of an Al-Ta-Al composite stack as a potential shielding against high-energy electrons. Experiments were performed at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The facility delivers a particle beam containing e-, μ- and π- with momentum from 17.5 to 345 MeV/c (Hajdas et al., 2014). The measurements of the radiation environment generated during the interaction of primary particles with the Al-Ta-Al material were conducted with dedicated beam diagnostic methods and with the NIM MCP detector. In parallel, modelling studies using GEANT4 and GRAS suites were performed to identify products of the interaction and predict ultimate fluxes and particle rates at the MCP detector. Combination of experiment and modelling studies yields detailed characterisation of the radiation fields produced by the interaction of the incident e- with the shielding material in the range of the beam momentum from 17.5 to 345 MeV/c. We derived the effective MCP detection efficiency to primary and secondary radiation and effective shielding transmission coefficients to incident high-energy electron beam in the range of applied beam momenta. This study shows that the applied shielding attenuates efficiently high-energy electrons. Nevertheless, owing to nearly linear increase of the bremsstrahlung production rate with incident beam energy, above 130 MeV their detection rates measured by the MCP

  2. Revised Full-Disk Spectra by Cassini-VIMS of the Saturnian Minor Icy Moons

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    This abstract concern with a detailed re-analysis of the disk-integrated spectra of the minor moons of Saturn (Atlas, Prometheus, Pandora, Janus, Epimetheus, Calypso and Telesto) obtained by Cassini-VIMS.

  3. Jupiter's Water Worlds

    NASA Technical Reports Server (NTRS)

    Pappalardo, R. T.

    2004-01-01

    When the twin Voyager spacecraft cruised past Jupiter in 1979, they did more than rewrite the textbooks on the giant planet. Their cameras also unveiled the astounding diversity of the four planet-size moons of ice and stone known as the Galilean satellites. The Voyagers revealed the cratered countenance of Callisto, the valleys and ridges of Ganymede, the cracked face of Europa, and the spewing volcanoes of Io. But it would take a spacecraft named for Italian scientist Galileo, who discovered the moons in 1610, to reveal the true complexity of these worlds and to begin to divulge their interior secrets. Incredibly, the Galileo data strongly suggest that Jupiter's three large icy moons (all but rocky Io) hide interior oceans.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  7. A multifluid magnetohydrodynamic simulation of the interaction between Jupiter's magnetosphere and its moon Europa

    NASA Astrophysics Data System (ADS)

    Rubin, M.; Jia, X.; Altwegg, K.; Combi, M. R.; Daldorff, L. K. S.; Gombosi, T. I.; Khurana, K. K.; Kivelson, M.; Tenishev, V.; Toth, G.; van der Holst, B.; Wurz, P.

    2015-12-01

    Jupiter's moon Europa is believed to contain a subsurface water ocean whose finite electrical conductance imposes clear induction signatures on the magnetic field in its surroundings. The evidence rests heavily on measurements performed by the magnetometer on board the Galileo spacecraft during multiple flybys of the moon. Europa's interaction with the Jovian magnetosphere has become a major target of research in planetary science, partly because of the potential of a salty ocean to harbor life outside our own planet. Thus it is of considerable interest to develop numerical simulations of the Europa-Jupiter interaction that can be compared with data in order to refine our knowledge of Europa's subsurface structure. In this presentation we show aspects of Europa's interaction with the Jovian magnetosphere extracted from a multifluid magnetohydrodynamics (MHD) code BATS-R-US recently developed at the University of Michigan. The model dynamically separates magnetospheric and pick-up ions and is capable of capturing some of the physics previously accessible only to kinetic approaches. The model utilizes an adaptive grid to maintain the high spatial resolution on the surface required to resolve the portion of Europa's neutral atmosphere with a scale height of a few tens of kilometers that is in thermal equilibrium. The model also derives the electron temperature, which is crucial to obtain the local electron impact ionization rates and hence the plasma mass loading in Europa's atmosphere. We compare our results with observations made by the plasma particles and fields instruments on the Galileo spacecraft to validate our model. We will show that multifluid MHD is able to reproduce the basic features of the plasma moments and magnetic field observations obtained during the Galileo E4 and E26 flybys at Europa.

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

    NASA Astrophysics Data System (ADS)

    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 (<100 kg), to be deployed by the mother spacecraft, that brings itself onto a collisional trajectory with the targeted planetary body in a simple manner. A possible science payload includes instruments for surface imaging, characterisation of the neutral exosphere, and magnetic field and plasma measurement near the target body down to very low-altitudes ( 1 km), during the probe's 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.

  9. Life detection strategy for Jovian's icy moons: Lessons from subglacial Lake Vostok exploration

    NASA Astrophysics Data System (ADS)

    Bulat, Sergey; Alekhina, Irina; Marie, Dominique; Petit, Jean-Robert

    2010-05-01

    The objective was to estimate the microbial content of accretion ice originating from the subglacial Lake Vostok buried beneath 4-km thick East Antarctic ice sheet with the ultimate goal to discover microbial life in this extreme icy environment. The DNA study constrained by Ancient DNA research criteria was used as a main approach. The flow cytometry was implemented in cell enumerating. As a result, both approaches showed that the accretion ice contains the very low unevenly distributed biomass indicating that the water body should also be hosting a highly sparse life. Up to now, the only accretion ice featured by mica-clay sediments presence allowed the recovery a pair of bacterial phylotypes. This unexpectedly included the chemolithoautotrophic thermophile Hydrogenophilus thermoluteolus and one more unclassified phylotype both passing numerous contaminant controls. In contrast, the deeper and cleaner accretion ice with no sediments presence and near detection limit gas content gave no reliable signals. Thus, the results obtained testify that the search for life in the Lake Vostok is constrained by a high chance of forward-contamination. The subglacial Lake Vostok seems to represent the only extremely clean giant aquatic system on the Earth providing a unique test area for searching for life on icy worlds. The life detection strategy for (sub)glacial environments elsewhere (e.g., Jovian's Europa) should be based on stringent decontamination procedures in clean-room facilities, establishment of on-site contaminant library, implementation of appropriate methods to reach detection level for signal as low as possible, verification of findings through ecological settings of a given environment and repetition at an independent laboratory within the specialized laboratory network.

  10. Stagnant lid convection in 3D-Cartesian geometry: Scaling laws and applications to icy moons and dwarf planets

    NASA Astrophysics Data System (ADS)

    Deschamps, Frédéric; Lin, Ja-Ren

    2014-04-01

    We conducted numerical experiments of stagnant lid thermal convection in 3D-Cartesian geometry, and use these experiments to derive parameterizations for the average internal temperature, heat flux, and stagnant lid thickness. Our experiments suggest that the non-dimensional temperature jump across the bottom thermal boundary layer (TBL) is well described by (1 -θm) = 1.23 (ΔTv / ΔT) , where θm is the non-dimensional average temperature of the convective sublayer, and ΔTv / ΔT a viscous temperature scale defined as the inverse of the logarithmic temperature derivative of viscosity. Due to the presence of the stagnant lid at the top of the fluid, the frequency of the time-variations of the surface heat flux is much lower than those of the bottom heat flux. The Nusselt number, measuring the heat transfer, is well explain by Nu = 1.46 Ram0.270 (ΔTv / ΔT)1.21 , where Ram is the effective Rayleigh number. This result indicates that the heat flux through the outer ice shells of large icy moons and dwarf planets is larger than that predicted by scalings in 2D-Cartesian geometry by 20-40%. We then apply our parameterizations to the dynamics of the outer ice I shells of icy moons and dwarf planets. As pointed out in previous studies, our calculations indicate that the presence of volatile in the primordial ocean of these bodies strongly reduces the vigor of convection within their outer ice I shell, the heat transfer through these shells, and the tectonic activity at their surface. Furthermore, thicker ice I layers may be achieved in bodies having low (0.7 m/s2) gravity acceleration (e.g., Pluto), than in bodies having larger (1.3 m/s2 and more) gravity acceleration (e.g., Europa, Ganymede, and Titan). Decrease in the surface temperature increases the thickness of the stagnant lid, which may result in a stronger lithosphere, and thus in fewer tectonic activity. Our parameterizations may also be used as boundary conditions at zero curvature to build parameterizations

  11. Ion implantation in ices and its relevance to the icy moons of the external planets

    NASA Astrophysics Data System (ADS)

    Strazzulla, G.; Baratta, G. A.; Fulvio, D.; Garozzo, M.; Leto, G.; Palumbo, M. E.; Spinella, F.

    2007-08-01

    Solid, atmosphere-less objects in the Solar System are continuously irradiated by energetic ions mostly in the keV-MeV energy range. Being the penetration depth of the incoming ions usually much lower than the thickness of the target, they are stopped into the ice. They deposit energy in the target induce the breaking of molecular bonds. The recombination of fragments produce different molecules. Reactive ions (e.g., H, C, N, O, S) induce all of the effects of any other ion, but in addition have a chance, by implantation in the target, to form new species containing the projectile. An ongoing research program performed at our laboratory has the aim to investigate ion implantation of reactive ions in many relevant ice mixtures. The results obtained so far indicate that some molecular species observed on icy planetary surfaces could not be native of that object but formed by implantation of reactive ions. In particular we present data obtained after: • C, N and S implantation in water ice • H implantation in carbon and sulfur dioxide

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

    NASA Astrophysics Data System (ADS)

    Beuthe, Mikael

    2016-12-01

    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 due to dynamical obliquity tides can differ from the static prediction by up to a factor of two.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of earth's moon, is apparently covered by water ice, as indicated by ground spectrometers and its brightness. In this view, global scale dark sreaks discovered by Voyager 1 that criss-cross the the satelite are becoming visible. Bright rayed impact craters, which are abundant on Ganymede and Callisto, would be easily visible at this range, suggesting that Europa's surface is young and that the streaks are reflections of currently active internal dynamic processes.

  15. Earth-based and Cassini-spacecraft Observations of Irregular Moons of Jupiter and Saturn

    NASA Astrophysics Data System (ADS)

    Denk, Tilmann; Mottola, S.; Roatsch, T.; Rosenberg, H.; Neukum, G.

    2010-10-01

    We observed irregular satellites of Jupiter and Saturn with the ISS camera of the Cassini spacecraft [1] and with the 1.23-m telescope of the Calar Alto observatory in Spain [2]. Scientific goals are the determination of rotation periods, rotation-axis orientations, spin directions, size parameters, color properties, phase curves, and searches for binaries. Himalia (J6), the largest of the irregular jovian moons, has been imaged by Cassini on 18 Dec 2000; a body size of 120±5 km x 150±10 km and an albedo of 0.05±0.01 have been measured [3,4]. Earth-based observations revealed that Himalia's rotation period is probably 9.3 h, which is in agreement with the 9.2 to 9.8 h suggested by [5], although periods of 7.8 or 11.7 h cannot be ruled out yet. In the saturnian system, 10 irregular moons were scheduled for Cassini ISS observations over time spans >9 hrs until end-of-August, 2010. Observation distances vary between 5.6 and 22 million km, corresponding to ISS pixel scales of 34 to 130 km. For the objects measured so far, the rotation periods vary significantly. For instance, Siarnaq (S/2000 S3; size 40 km) and Ymir (S/2000 S1; 18 km) exhibit rotation periods of 6.7 h and 7.3 h, respectively, while Kiviuq (S/2000 S5; 16 km) might take about 22 h for one rotation. First results from the observation campaigns will be presented at the meeting. References: [1] Porco, C.C., et al. (2004), Space Sci. Rev. 115, 363; [2] http://www.caha.es/CAHA/Telescopes/1.2m.html; [3] Denk, T. et al. (2001), Conference on Jupiter (Planet, Satellites & Magnetosphere), Boulder, CO, 25-30 June 2001, abstracts book p. 30-31; [4] Porco, C.C., et al. (2003), Science 299, 1541; [5] Degewij, J., et al. (1980), Icarus 44, 520. We gratefully acknowledge funding by the German Space Agency (DLR) Bonn through grant no. 50 OH 0305.

  16. Bacterial Motility As a Biosignature: Tests at Icy Moon Analogue Sites

    NASA Astrophysics Data System (ADS)

    Nadeau, J. L.; Lindensmith, C.; Deming, J. W.; Stocker, R.; Graff, E.; Serabyn, E.; Wallace, J. K.; Liewer, K.; Kuhn, J.

    2014-12-01

    Extraterrestrial life in our Solar System, if present, is almost certain to be microbial. Methods and technologies for unambiguous detection of living or extinct microorganisms are needed for life-detection missions to the Jovian and Saturnian moons, where liquid water is known to exist. Our research focuses specifically on microbial meaningful motion as a biosignature—"waving crowds" at the micron scale. Digital Holographic Microscopy (DHM) is an excellent tool for unambiguous identification of bacterial and protozoal swimming, even in the presence of turbidity, drift, and currents. The design of a holographic instrument with bacteria scale resolution was described in the previous talk. In this presentation, we will illustrate the design challenges for construction of a field instrument for extreme environments and space, and present plans for scientific investigations at analogue sites for the coming season. The challenges of creating a field instrument involve performance trade-offs, the ability to operate at extreme temperatures, and handling large volumes of data. A fully autonomous instrument without external cables or power is also desirable, and this is something that previous holographic instruments have not achieved. The primary issues for space exploration are identification of a laser and drive electronics that are qualified for the expected radiation environments of the moons around gas giant planets. Tests in Earth analogue environments will establish performance parameters as well as answer scientific questions that traditional microscopic techniques cannot. Specifically, we will visit a Greenland field site to determine whether or not microorganisms are motile within the brine-filled interior network of sea ice, and if they can be autonomously tracked using the instrument. Motility within the liquid phase of a frozen matrix has been hypothesized to explain how bacteria contribute to the biogeochemical signatures detected in ice, but observational

  17. Moon

    NASA Technical Reports Server (NTRS)

    1996-01-01

    During its flight, the Galileo spacecraft returned images of the Moon. The Galileo spacecraft took these images on December 7, 1992 on its way to explore the Jupiter system in 1995-97. The distinct bright ray crater at the bottom of the image is the Tycho impact basin. The dark areas are lava rock filled impact basins: Oceanus Procellarum (on the left), Mare Imbrium (center left), Mare Serenitatis and Mare Tranquillitatis (center), and Mare Crisium (near the right edge). This picture contains images through the Violet, 756 nm, 968 nm filters. The color is 'enhanced' in the sense that the CCD camera is sensitive to near infrared wavelengths of light beyond human vision. The Galileo project is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

  18. Detecting Darwinism from Molecules in the Enceladus Plumes, Jupiter's Moons, and Other Planetary Water Lagoons.

    PubMed

    Benner, Steven A

    2017-09-01

    To the astrobiologist, Enceladus offers easy access to a potential subsurface biosphere via the intermediacy of a plume of water emerging directly into space. A direct question follows: If we were to collect a sample of this plume, what in that sample, through its presence or its absence, would suggest the presence and/or absence of life in this exotic locale? This question is, of course, relevant for life detection in any aqueous lagoon that we might be able to sample. This manuscript reviews physical chemical constraints that must be met by a genetic polymer for it to support Darwinism, a process believed to be required for a chemical system to generate properties that we value in biology. We propose that the most important of these is a repeating backbone charge; a Darwinian genetic biopolymer must be a "polyelectrolyte." Relevant to mission design, such biopolymers are especially easy to recover and concentrate from aqueous mixtures for detection, simply by washing the aqueous mixtures across a polycharged support. Several device architectures are described to ensure that, once captured, the biopolymer meets two other requirements for Darwinism, homochirality and a small building block "alphabet." This approach is compared and contrasted with alternative biomolecule detection approaches that seek homochirality and constrained alphabets in non-encoded biopolymers. This discussion is set within a model for the history of the terran biosphere, identifying points in that natural history where these alternative approaches would have failed to detect terran life. Key Words: Enceladus-Life detection-Europa-Icy moon-Biosignatures-Polyelectrolyte theory of the gene. Astrobiology 17, 840-851.

  19. The survival of large organic molecules during hypervelocity impacts with water ice: implications for sampling the icy surfaces of moons

    NASA Astrophysics Data System (ADS)

    Hurst, A.; Bowden, S. A.; Parnell, J.; Burchell, M. J.; Ball, A. J.

    2007-12-01

    There are a number of measurements relevant to planetary geology that can only be adequately performed by physically contacting a sample. This necessitates landing on the surface of a moon or planetary body or returning samples to earth. The need to physically contact a sample is particularly important in the case of measurements that could detect medium to low concentrations of large organic molecules present in surface materials. Large organic molecules, although a trace component of many meteoritic materials and rocks on the surface of earth, carry crucial information concerning the processing of meteoritic material in the surface and subsurface environments, and can be crucial indicators for the presence of life. Unfortunately landing on the surface of a small planetary body or moon is complicated, particularly if surface topography is only poorly characterised and the atmosphere thin thus requiring a propulsion system for a soft landing. One alternative to a surface landing may be to use an impactor launched from an orbiting spacecraft to launch material from the planets surface and shallow sub-surface into orbit. Ejected material could then be collected by a follow-up spacecraft and analyzed. The mission scenario considered in the Europa-Ice Clipper mission proposal included both sample return and the analysis of captured particles. Employing such a sampling procedure to analyse large organic molecules is only viable if large organic molecules present in ices survive hypervelocity impacts (HVIs). To investigate the survival of large organic molecules in HVIs with icy bodies a two stage light air gas gun was used to fire steel projectiles (1-1.5 mm diameter) at samples of water ice containing large organic molecules (amino acids, anthracene and beta-carotene a biological pigment) at velocities > 4.8 km/s.UV-VIS spectroscopy of ejected material detected beta-carotene indicating large organic molecules can survive hypervelocity impacts. These preliminary results

  20. Jupiter

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Murdin, P.

    2002-10-01

    At 5.2 AU from the Sun (table 1), Jupiter is the closest and the most massive of the GIANT PLANETS, which extend in the outer solar system up to heliocentric distances of 30 AU. Its mass amounts to 318 terrestrial masses, and its diameter is 11 times the terrestrial one (table 2). Like the other giant planets, Jupiter has a low density (1.31 g cm-3) which reflects its chemical composition, mostly ...

  1. Electric Properties of Water Ice doped with Hydrogen Peroxide (H2O2): Implications for Icy Moons such as Europa

    NASA Astrophysics Data System (ADS)

    Keller, C.; Freund, F. T.; Cruikshank, D. P.

    2012-12-01

    Large floats of ice on Jupiter's moon Europa drift and collide. The float boundaries are marked by brownish-reddish colors. The origin of these colors is poorly understood. Maybe upwelling of water along the active float boundaries brings finely divided suspended matter or organic compounds from the ocean below to the surface, where the intense, high energy environment in Jupiter's radiation belt would lead to photochemical oxidation. At the same time it has been suggested that Europa's ice contains traces of H2O2, presumably due to micro-meteorite impacts and other processes. We measured the electric currents generated in pure and H2O2-doped water ice when we subjected one end of ice blocks to uniaxial stress. Ice samples with 0%, 0.3% and 0.03% H2O2 were formed in polyethylene troughs, 4.1 x 13.5 x 3.8 cm, with Cu contacts at both ends, at 263K (-10°C), 190K (-78°C, dry ice) and 77K (-196°C,liquid N2). At 77K the ice samples detached themselves from at least one of the Cu contacts, due to thermal contraction. At 190K, when stressing one end, essentially no currents were produced in the pure water ice. By contrast, H2O2-doped ices produced several hundred picoamperes (pA) of positive currents, indicating defect electrons (holes) flowing down the stress gradient. At 263K the results are ambiguous. These (as yet preliminary) results indicate that stresses might break the peroxy bonds of imbedded H2O2 molecules, releasing the same type of positive hole charge carriers as observed during stress experiments with silicate rocks. Since positive holes are defect electrons associated with O 2sp levels at the upper edge of the valence band, they seem to have the capability to spread through the ices. Chemically positive holes are equivalent to highly oxidizing oxygen radicals. They may be responsible for oxidation reactions along the boundaries of active ice floats on Europa.

  2. Project CLEA - The Moons of Jupiter: Understanding the Kepler's Laws in Astronomy 101

    NASA Astrophysics Data System (ADS)

    Ruzhitskaya, Lanika; Speck, A.

    2008-05-01

    We report results on a study of impact of Project CLEA - Contemporary Laboratory Experiences in Astronomy software on students’ understanding of the Kepler's Third Law. The study was conducted at the University of Missouri among 26 non-science major students enrolled in an introductory astronomy course. There were 16 female and 15 male students participants between age of 18 and 24. The study was designed to find out whether students had different attitudes toward the simulation: its visual design and its intuitiveness and easiness to use. The study tested whether these attitudes reflected on the students’ learning outcomes of the discussed astronomy topic. To measure students’ computer proficiency and how comfortable they were using computers they were given a computer attitude inventory. The participants took a pretest and a posttest designed by the Project CLEA developers for the Moons of Jupiter module. The students also filled out a questionnaire where they reflected on their experience of using the software. Two weeks later the research participants took a final astronomy course examination which included a question on the Kepler's Third Law. Our research shows that students who indicated that they liked the simulation performed better on the posttest.. At the same time, we found that there was no relationship between the students’ attitude towards the simulation and their performance on the final exam. Students, who used CLEA simulation regardless of their attitudes towards it, significantly outperformed their classmates during the final exam on the Kepler's third law question. It is also interesting to note that students performed better on five out of six posttest questions - there was no change on a question involved mathematical application of the Kepler's Third Law formula.

  3. Gravity is the Key Experiment to Address the Habitability of the Ocean in Jupiter's Moon Europa

    NASA Astrophysics Data System (ADS)

    Sessa, A. M.; Dombard, A. J.

    2013-12-01

    Life requires three constituents: a liquid solvent (i.e., water), a chemical system that can form large molecules to record genetic information (e.g., carbon based) as well as chemical nutrients (e.g., nitrogen, phosphorous), and a chemical disequilibrium system that can provide metabolic energy. While it is believed that there is a saline water layer located between the rock and ice layers in Jupiter's moon Europa, which would satisfy the first requirement, it is unknown if the other conditions are currently met. The likelihood that Europa is a haven for life in our Solar System skyrockets, however, if there is currently active volcanism at the rock-water interface, much the same that volcanic processes enable the chemosynthetic life that forms the basis of deep sea-vent communities at the bottom of Earth's oceans. Exploring the volcanic activity on this interface is challenging, as direct observation via a submersible or high-resolution indirect observations via a dense global seismic network on the surface is at present technically (and fiscally!) untenable. Thus, gravity studies are the best way to explore currently the structure of this all-important interface. Though mostly a silicate body with only a relatively thin (~100 km) layer of water, Europa is different from the terrestrial planets in that this rock-water interface, and not the surface, represents the largest density contrast across the moon's near-surface layers, and thus topography on this interface could conceivably dominate the gravity. Here, we calculate the potential anomalies that arise from topography on the surface, the water-ice interface (at 20 km depth), and the rock-water interface, finding that the latter dominates the free-air gravity at the longest wavelengths (spherical harmonic degrees < 10) and the Bouguer gravity at intermediate wavelengths (degrees ~10-50), and only for the shortest wavelengths (degrees > 50) does the water-ice interface (and presumably mass-density anomalies

  4. Engineering a Solution to Jupiter Exploration

    NASA Technical Reports Server (NTRS)

    Clark, Karla; Magner, Thomas; Lisano, Michael; Pappalardo, Robert

    2010-01-01

    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) explore Europa to investigate its habitability, (2) characterize Ganymede as a planetary object including its potential habitability and (3) explore the Jupiter system as an archetype for gas giants. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with conceptual orbiters developed by NASA and ESA. The baseline EJSM architecture consists of two primary elements operating simultaneously 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 importantly, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM baseline architecture would provide 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

  5. Engineering a Solution to Jupiter Exploration

    NASA Technical Reports Server (NTRS)

    Clark, Karla; Magner, Thomas; Lisano, Michael; Pappalardo, Robert

    2010-01-01

    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) explore Europa to investigate its habitability, (2) characterize Ganymede as a planetary object including its potential habitability and (3) explore the Jupiter system as an archetype for gas giants. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with conceptual orbiters developed by NASA and ESA. The baseline EJSM architecture consists of two primary elements operating simultaneously 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 importantly, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM baseline architecture would provide 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

  6. Jupiter

    NASA Image and Video Library

    1998-06-04

    This processed color image of Jupiter was produced in 1990 by the U.S. Geological Survey from a Voyager image captured in 1979. Zones of light-colored, ascending clouds alternate with bands of dark, descending clouds. http://photojournal.jpl.nasa.gov/catalog/PIA00343

  7. Stagnant lid convection in bottom-heated thin 3-D spherical shells: Influence of curvature and implications for dwarf planets and icy moons

    NASA Astrophysics Data System (ADS)

    Yao, C.; Deschamps, F.; Lowman, J. P.; Sanchez-Valle, C.; Tackley, P. J.

    2014-08-01

    Because the viscosity of ice is strongly temperature dependent, convection in the ice layers of icy moons and dwarf planets likely operates in the stagnant lid regime, in which a rigid lid forms at the top of the fluid and reduces the heat transfer. A detailed modeling of the thermal history and radial structure of icy moons and dwarf planets thus requires an accurate description of stagnant lid convection. We performed numerical experiments of stagnant lid convection in 3-D spherical geometries for various ice shell curvatures f (measured as the ratio between the inner and outer radii), effective Rayleigh number Ram, and viscosity contrast Δη. From our results, we derived scaling laws for the average temperature of the well-mixed interior, θm, and the heat flux transported through the shell. The nondimensional temperature difference across the bottom thermal boundary layer is well described by (1-θm)=1.23γ/f1.5, where γ is a parameter that controls the magnitude of the viscosity contrast. The nondimensional heat flux at the bottom of the shell, Fbot, scales as Fbot=1.46Ram0.27γ1.21/f1.78. Our models also show that the development of the stagnant lid regime depends on f. For given values of Ram and Δη, the stagnant lid is less developed as the shell's curvature increases (i.e., as f decreases), leading to improved heat transfer. Therefore, as the outer ice shells of icy moons and dwarf planets grow, the effects of a stagnant lid are less pronounced.

  8. Phase diagram of the binary H2O-NaCl and salty ice VII at pressure and temperature conditions of exoplanets and large icy moons

    NASA Astrophysics Data System (ADS)

    Journaux, B.; Daniel, I.

    2011-10-01

    We present here the first experimental data for the phase diagram of the H2O-NaCl system at high. Our results show a significant influence of NaCl on the phase diagram. A lot of NaCl is directly disolved into the dense ice phase. This would increase the depth of the solid phase transition inside large icy moons or super-earth exoplanets. These results may have major implication for astrophysical, geophysical and geodynamical modelisations of this water-rich planetary bodies.

  9. Development of 2-D Array of Superconducting Magnesium Diboride (MgB2) for Far-IR Investigations of the Outer Planets and Icy Moons

    NASA Astrophysics Data System (ADS)

    Lakew, Brook

    2009-09-01

    A 2-D array of superconducting Magnesium Diboride(MgB2) far -IR thermal detectors has been fabricated. Such an array is intended to be at the focal plane of future generation thermal imaging far-IR instruments that will investigate the outer planets and their icy moons. Fabrication and processing of the pixels of the array as well as noise characterization of architectured MgB2 thin films will be presented. Challenges and solutions for improving the performance of the array will be discussed.

  10. Why Europa's icy shell may convect, but ice sheets do not: a glaciological perspective

    NASA Astrophysics Data System (ADS)

    Bassis, J. N.

    2016-12-01

    Jupiter's moon Europa is covered in an icy shell that lies over a liquid ocean. Geological evidence and numerical models suggest that Europa's icy shell convects, providing the possibility that Europa may experience a form of plate tectonics and could even harbor life in its subsurface ocean. The hypothesis that Europa convects is supported by both models and geological evidence. Surprisingly, when we apply similar calculations and (assumptions) used by planetary scientists to infer convection in icy moons like Europa we find that these models also predict that vigorous convection should also occur in portions of our own terrestrial ice sheets and ice shelves where we have firm evidence to the contrary. We can explain the lack of convection within our own ice sheets by recognizing that instead of the diffusion creep limited rheology frequently invoked by planetary scientists, terrestrial ice undergoes power-law creep down to very low strain rates. Glaciological studies find that power-law creep is required to explain the structure of vertical strain rate near ice sheet divides and shape of the ice sheets near an ice divide. However, when we now apply a rheology that is consistent with terrestrial ice sheet dynamics to icy moon conditions, we find conditions are far less favorable for convection in icy moons, with only a very limited parameter regime where convection can occur. Given the many unknowns (grain size, impurities etc.) it is challenging to draw strong conclusions about the behavior of icy moons . Nonetheless, the lack of convection in terrestrial ice sheets provides an important constraint on the dynamics of icy moons and models that explain convection of icy moons should also explain the lack of convection on terrestrial ice sheets.

  11. Infrared Spectra of Hydrated Magnesium Salts and their Role in the Search for Possible Life Conditions on Jupiter Moons

    NASA Technical Reports Server (NTRS)

    Chaban, Galina; Huo, Winifred M.; Lee, Timothy J.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    Recent observations from the Galileo satellite indicate that three of the Jupiter moons, Europa, Ganymede, and Callisto, may have subsurface oceans. Possible existence of such ocean and the nature of its composition are of great interest to astrobiologists. Data from Galileo's NIMS spectrometer indicate the possibility of hydrated salts on Europa's surface. To aid in the design of future missions, we investigated infrared spectra of MgSO4-nH20, n=1-3 using ab initio calculations. Geometry, energetics, dipole moments, vibrational frequencies and infrared intensities of pure and hydrated MgSO4 salts were determined. Significant differences are found between vibrational spectra of water molecules in complexes with MgSO4 and pure water. Some of the O-H stretching frequencies in the complexes are shifted to the red by up to 1,500 - 2,000 per cm. In addition, the SO2 stretching vibrations are found at lower frequency regions than the water vibrations. The calculated bands of water and SO2 fragments can serve as markers for the existence of the salt-water complexes on the surface of Jupiter's moon.

  12. Infrared Spectra of Hydrated Magnesium Salts and their Role in the Search for Possible Life Conditions on Jupiter Moons

    NASA Technical Reports Server (NTRS)

    Chaban, Galina; Huo, Winifred M.; Lee, Timothy J.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    Recent observations from the Galileo satellite indicate that three of the Jupiter moons, Europa, Ganymede, and Callisto, may have subsurface oceans. Possible existence of such ocean and the nature of its composition are of great interest to astrobiologists. Data from Galileo's NIMS spectrometer indicate the possibility of hydrated salts on Europa's surface. To aid in the design of future missions, we investigated infrared spectra of MgSO4-nH20, n=1-3 using ab initio calculations. Geometry, energetics, dipole moments, vibrational frequencies and infrared intensities of pure and hydrated MgSO4 salts were determined. Significant differences are found between vibrational spectra of water molecules in complexes with MgSO4 and pure water. Some of the O-H stretching frequencies in the complexes are shifted to the red by up to 1,500 - 2,000 per cm. In addition, the SO2 stretching vibrations are found at lower frequency regions than the water vibrations. The calculated bands of water and SO2 fragments can serve as markers for the existence of the salt-water complexes on the surface of Jupiter's moon.

  13. Medium-sized icy satellites in the outer solar system - differentiation due to radiogenic heating in Charon or the moons of Uranus?

    NASA Astrophysics Data System (ADS)

    Multhaup, K.; Spohn, T.

    2007-08-01

    A thermal history model developed for medium-sized icy satellites containing silicate rock at low volume fractions is applied to Charon and five satellites of Uranus. The model assumes stagnant lid convection in homogeneously accreted bodies either confined to a spherical shell or encompassing the whole interior below the immobile surface layer. We employ a simple model for accretion assuming that infalling planetesimals deposit a fraction of their kinetic energy as heat at the instantaneous surface of the growing moon. Rheology parameters are chosen to match those of ice I, although the satellites under consideration likely contain admixtures of lighter constituents. Consequences thereof are discussed. Thermal evolution calculations considering radiogenic heating by long-lived isotopes suggest that Ariel, Umbriel, Titania, Oberon and Charon may have started to differentiate after a few hundred million years of evolution. Results for Miranda - the smallest satellite of Uranus - however, indicate that it never convected or differentiated. Miranda's interior temperature was found to be not even close to the melting temperatures of reasonable mixtures of water and ammonia. This finding is in contrast to its heavily modified surface and supports theories that propose alternative heating mechanisms such as early tidal heating. Except for Miranda, our results lend support to differentiated icy satellite models. We also point out parallels to previously published results obtained for several of Saturn's icy satellites (Multhaup and Spohn, 2007). The predicted early histories of Ariel, Umbriel and Charon are evocative of Dione's and Rhea's, while Miranda's resembles that of Mimas.

  14. Effects of an eccentric inner Jupiter on the dynamical evolution of icy body reservoirs in a planetary scattering scenario

    NASA Astrophysics Data System (ADS)

    Zanardi, M.; de Elía, G. C.; Di Sisto, R. P.; Naoz, S.; Li, G.; Guilera, O. M.; Brunini, A.

    2017-09-01

    Aims: We analyze the dynamics of small body reservoirs under the effects of an eccentric inner giant planet resulting from a planetary scattering event around a 0.5 M⊙ star. Methods: First, we used a semi-analytical model to define the properties of the protoplanetary disk that lead to the formation of three Jupiter-mass planets. Then, we carried out N-body simulations assuming that the planets are close to their stability limit together with an outer planetesimal disk. In particular, the present work focused on the analysis of N-body simulations in which a single Jupiter-mass planet survives after the dynamical instability event. Results: Our simulations produce outer small body reservoirs with particles on prograde and retrograde orbits, and other ones whose orbital plane flips from prograde to retrograde and back again along their evolution ("Type-F particles"). We find strong correlations between the inclination i and the ascending node longitude Ω of Type-F particles. First, Ω librates around 90° or/and 270°. This property represents a necessary and sufficient condition for the flipping of an orbit. Moreover, the libration periods of i and Ω are equal and they are out to phase by a quarter period. We also remark that the larger the libration amplitude of i, the larger the libration amplitude of Ω. We analyze the orbital parameters of Type-F particles immediately after the instability event (post IE orbital parameters), when a single Jupiter-mass planet survives in the system. Our results suggest that the orbit of a particle can flip for any value of its post IE eccentricity, although we find only two Type-F particles with post IE inclinations i ≲ 17°. Finally, our study indicates that the minimum value of the inclination of the Type-F particles in a given system decreases with an increase in the eccentricity of the giant planet.

  15. Phase diagram and density of fluids in the water-methanol system: experiments and implications for the crystallization and dynamics of subsurface oceans in icy moons

    NASA Astrophysics Data System (ADS)

    Yao, C.; Mantegazzi, D.; Deschamps, F.; Sanchez-Valle, C.

    2013-12-01

    Methanol, CH3OH, has been recently observed in several comets and at the surface of Saturn's icy moon Enceladus, [Hodyss et al., 2009]. Its plausible presence in the subsurface ocean could significantly affect the thermal and structural evolution of the satellite [Deschamps et al., 2010]. Methanol lowers the melting temperature of water ice [Vuillard & Sanchez, 1961; Miller & Carpenter, 1964], hence decreasing the efficiency of convective heat transfer through the outer ice Ih shell, and affects the subsurface ocean density and thermo-chemical evolution. However, the phase diagram and the fluid density of the H2O - CH3OH system remains largely unknown at the high pressures and low temperature conditions relevant for the icy moon interiors. In this study, we determined experimentally the liquidus temperature of Ice Ih and Ice VI and the fluid density in the binary water-methanol system (5, 10 and 20 w% CH3OH) from sound velocity measurments by Brillouin scattering spectroscopy over the P-T range 230 - 300 K and 10-4 - 1.2 GPa. The experiments were conducted using a membrane-type diamond anvil cell (mDAC) and an in-house designed Peltier cooling system to achieve the low temperatures of interest. Melting and crystallization in the system was visually monitored and confirmed from changes in the Brillouin spectra and in the pressure dependence of the measured sound velocities. The density of fluids ρ(P, T,x) in the binary system weas determined from the inversion of sound velocities measured in the fluids as a function of pressure along isotherms from 230 to 300 K. The results are used to propose a thermodynamic model for the CH3OH-H2O system over the investigated P-T range and further used to examine the effect of the methanol on the crystallization and thermo-chemical evolution of the subsurface ocean. The implications of these results for the thermal and structural evolution of icy moons, with particular applications to Titan, will be further discussed. References

  16. Moon

    Atmospheric Science Data Center

    2013-04-19

    article title:  MISR Views the Moon     View Larger Image On ... instruments to look at deep space and the waxing gibbous Moon. The purpose of this acrobatic feat is to assist in the calibration of ...

  17. Next-Generation Laser Retroreflectors for the Science and Exploration of the Moon, Mars and Beyond

    NASA Astrophysics Data System (ADS)

    Dell'Agnello, S.; SCF Lab Team; Currie, D.; Richards, R.; Chandler, J.

    2016-10-01

    We describe next-generation laser retroreflectors for solar system science/exploration, developed at INFN-LNF, Frascati, Italy in collaboration with ASI and NASA-SSERVI, for lunar missions, ExoMars, Mars2020, Phobos, Jupiter icy/rocky moons, asteroids.

  18. The H2O and O2 exospheres of Ganymede: The result of a complex interaction between the jovian magnetospheric ions and the icy moon

    NASA Astrophysics Data System (ADS)

    Plainaki, Christina; Milillo, Anna; Massetti, Stefano; Mura, Alessandro; Jia, Xianzhe; Orsini, Stefano; Mangano, Valeria; De Angelis, Elisabetta; Rispoli, Rosanna

    2015-01-01

    The H2O and O2 exospheres of Jupiter's moon Ganymede are simulated through the application of a 3D Monte Carlo modeling technique that takes into consideration the combined effect on the exosphere generation of the main surface release processes (i.e. sputtering, sublimation and radiolysis) and the surface precipitation of the energetic ions of Jupiter's magnetosphere. In order to model the magnetospheric ion precipitation to Ganymede's surface, we used as an input the electric and magnetic fields from the global MHD model of Ganymede's magnetosphere (Jia, X., Walker, R.J., Kivelson, M.G., Khurana, K.K., Linker, J.A. [2009]. J. Geophys. Res. 114, A09209). The exospheric model described in this paper is based on EGEON, a single-particle Monte Carlo model already applied for a Galilean satellite (Plainaki, C., Milillo, A., Mura, A., Orsini, S., Cassidy, T. [2010]. Icarus 210, 385-395; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Massetti, S., Cassidy, T. [2012]. Icarus 218 (2), 956-966; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Saur [2013]. Planet. Space Sci. 88, 42-52); nevertheless, significant modifications have been implemented in the current work in order to include the effect on the exosphere generation of the ion precipitation geometry determined strongly by Ganymede's intrinsic magnetic field (Kivelson, M.G. et al. [1996]. Nature 384, 537-541). The current simulation refers to a specific configuration between Jupiter, Ganymede and the Sun in which the Galilean moon is located close to the center of Jupiter's Plasma Sheet (JPS) with its leading hemisphere illuminated. Our results are summarized as follows: (a) at small altitudes above the moon's subsolar point the main contribution to the neutral environment comes from sublimated H2O; (b) plasma precipitation occurs in a region related to the open-closed magnetic field lines boundary and its extent depends on the assumption used to mimic the plasma mirroring in Jupiter's magnetosphere; (c) the

  19. Salt partitioning between water and high-pressure ices. Implication for the dynamics and habitability of icy moons and water-rich planetary bodies

    NASA Astrophysics Data System (ADS)

    Journaux, Baptiste; Daniel, Isabelle; Petitgirard, Sylvain; Cardon, Hervé; Perrillat, Jean-Philippe; Caracas, Razvan; Mezouar, Mohamed

    2017-04-01

    Water-rich planetary bodies including large icy moons and ocean exoplanets may host a deep liquid water ocean underlying a high-pressure icy mantle. The latter is often considered as a limitation to the habitability of the uppermost ocean because it would limit the availability of nutrients resulting from the hydrothermal alteration of the silicate mantle located beneath the deep ice layer. To assess the effects of salts on the physical properties of high-pressure ices and therefore the possible chemical exchanges and habitability inside H2O-rich planetary bodies, we measured partitioning coefficients and densities in the H2O-RbI system up to 450 K and 4 GPa; RbI standing as an experimentally amenable analog of NaCl in the H2O-salt solutions. We measured the partitioning coefficient of RbI between the aqueous fluid and ices VI and VII, using in-situ Synchrotron X-ray Fluorescence (XRF). With in-situ X-ray diffraction, we measured the unit-cell parameters and the densities of the high-pressure ice phases in equilibrium with the aqueous fluid, at pressures and temperatures relevant to the interior of planetary bodies. We conclude that RbI is strongly incompatible towards ice VI with a partitioning coefficient Kd(VI-L) = 5.0 (± 2.1) ṡ10-3 and moderately incompatible towards ice VII, Kd(VII-L) = 0.12 (± 0.05). RbI significantly increases the unit-cell volume of ice VI and VII by ca. 1%. This implies that RbI-poor ice VI is buoyant compared to H2O ice VI while RbI-enriched ice VII is denser than H2O ice VII. These new experimental results might profoundly impact the internal dynamics of water-rich planetary bodies. For instance, an icy mantle at moderate conditions of pressure and temperature will consist of buoyant ice VI with low concentration of salt, and would likely induce an upwelling current of solutes towards the above liquid ocean. In contrast, a deep and/or thick icy mantle of ice VII will be enriched in salt and hence would form a stable chemical boundary

  20. Ground-based near infrared spectroscopy of Jupiter's ring and moons

    NASA Astrophysics Data System (ADS)

    Wong, Michael H.; de Pater, Imke; Showalter, Mark R.; Roe, Henry G.; Macintosh, Bruce; Verbanac, Giuli

    2006-12-01

    The backscattered reflectivity of Jupiter's ring has been previously measured over distinct visible and near infrared wavelength bands by a number of ground-based and spaceborne instruments. We present spectra of Jupiter's main ring from 2.21-2.46 μm taken with the NIRSPEC spectrometer at the W.M. Keck observatory. At these wavelengths, scattered light from Jupiter is minimal due to the strong absorption of methane in the planet's atmosphere. We find an overall flat spectral slope over this wavelength interval, except for a possible red slope shortward of 2.25 μm. We extended the spectral coverage of the ring to shorter wavelengths by adding a narrow-band image at 1.64 μm, and show results from 2.27-μm images over phase angles of 1.2°-11.0°. Our images at 1.64 and 2.27 μm reveal that the halo contribution is stronger at the shorter wavelength, possibly due to the redder spectrum of the ring parent bodies as compared with the halo dust component. We find no variation in main ring reflectivity over the 1.2°-11.0° phase angle range at 2.27 μm. We use adaptive optics imaging at the longer wavelength L' band (3.4-4.1 μm) to determine a 2- σ upper limit of 22 m of vertically-integrated I/F. Our observing campaign also produced an L' image of Callisto, showing a darker leading hemisphere, and a spectrum of Amalthea over the 2.2-2.5 and 2.85-3.03 μm ranges, showing deep 3-μm absorption.

  1. Jupiter's and Saturn's ice moons: geophysical aspects and opportunities of geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons

    NASA Astrophysics Data System (ADS)

    Ozorovich, Yuri; Linkin, Vacheslav; Kosov, Alexandr; Fournier-Sicre, Alain; Klimov, Stanislav; Novikov, Denis; Ivanov, Anton; Skulachev, Dmitriy; Menshenin, Yaroslav

    2016-04-01

    This paper presents a new conceptual and methodological approach for geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons on the base "conceptual design phase" of the future space missions on the ice moons. At the design stage of such projects is considered the use of various space instruments and tools for the full the complex geophysical studies of the manifestations and planetary processes of the subsurface liquid ocean on the surface ice moons. The existence of various forms of the cryolithozone on terrestrial planets and their moons: advanced Martian permafrost zone in the form of existing of the frozen polar caps, subsurface frozen horizons, geological markers and oreols of the martian ancient (relict) ocean, subsurface oceans of Jupiter's and Saturn's moons-Europe and Enceladus, with the advanced form of permafrost freezes planetary caps, it allows to develop a common methodological basis and operational geophysical instruments (tools) for the future space program and planning space missions on these unique objects of the solar system, specialized for specific scientific problems of planetary missions. Geophysical practices and methodological principles, used in 1985-2015 by aurthors [ 1-5 ], respectively, as an example of the comprehensive geophysical experiment MARSES to study of the Martian permafrost zone and the martian ancient (relict) ocean, creating the preconditions for complex experimental setting and geo-physical monitoring of operational satellites of Jupiter and Saturn- Europe and Enceladus. This range of different planetary (like) planets with its geological history and prehistory of the common planetology formation processes of the planets formation and to define the role of a liquid ocean under the ice as a climate indicator of such planets, which is extremely important for the future construction of the geological and climatic history of the Earth. Main publications: [1

  2. Outer Planet Icy Satellites

    NASA Technical Reports Server (NTRS)

    Buratti, B.

    1994-01-01

    An outer planet icy satellite is any one of the celestial bodies in orbit around Jupiter, Saturn, Uranus, Neptune, or Pluto. They range from large, planet-like geologically active worlds with significant atmospheres to tiny irregular objects tens of kilometers in diameter. These bodies are all believed to have some type of frozen volatile, existing alone or in combination with other volatiles.

  3. News conference on Voyager-2-Jupiter encounter

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The proceedings of a news conference on the Voyager 2 Jupiter project are presented. Topics include the instrumentation on the Voyager 2, Jupiter's atmosphere and magnetic field, the Jupiter moons, and the observations of lightning on Jupiter.

  4. JIMO Delivery and Support of a Jupiter Deep Entry Probe

    NASA Technical Reports Server (NTRS)

    Spilker, T. R.; Young, R. E.

    2003-01-01

    The 2003 Solar System Exploration Decadal Survey ('SSEDS') emphasizes the significant science available from Jupiter deep entry probes. Studies performed at JPL this year identified a mission design that would allow JIMO to deliver and support one or more entry probes that reach the 100-bar level in Jupiter's atmosphere, with relatively minor modifications to JIMO s preliminary mission design. Notably, the icy moon tour mission design, beginning with Callisto approach, is unaffected. This proposed mission design would offer the option of adding a rich new set of high-priority SSEDS science objectives to the planned JIMO mission for a relatively small investment.

  5. Sounding of Icy Galilean Satellites by Surface Observatories

    NASA Technical Reports Server (NTRS)

    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.

  6. On the state of water ice on saturn's moon Titan and implications to icy bodies in the outer solar system.

    PubMed

    Zheng, Weijun; Jewitt, David; Kaiser, Ralf I

    2009-10-22

    The crystalline state of water ice in the Solar System depends on the temperature history of the ice and the influence of energetic particles to which it has been exposed. We measured the infrared absorption spectra of amorphous and crystalline water ice in the 10-50 K and 10-140 K temperature ranges, respectively, and conducted a systematic experimental study to investigate the amorphization of crystalline water ice via ionizing radiation irradiation at doses of up to 160 +/- 30 eV per molecule. We found that crystalline water ice can be converted only partially to amorphous ice by electron irradiation. The experiments showed that a fraction of the 1.65 microm band, which is characteristic for crystalline water ice, survived the irradiation, to a degree that strongly depends on the temperature. Quantitative kinetic fits of the temporal evolution of the 1.65 mum band clearly demonstrate that there is a balance between thermal recrystallization and irradiation-induced amorphization, with thermal recrystallizaton dominant at higher temperatures. Our experiments show the amorphization at 40 K was incomplete, in contradiction to Mastrapa and Brown's conclusion (Icarus 2006, 183, 207.). At 50 K, the recrystallization due to thermal effects is strong, and most of the crystalline ice survived. Temperatures of most icy objects in the Solar System, including Jovian satellites, Saturnian satellites (including Titan), and Kuiper Belt Objects, are equal to or above 50 K; this explains why water ice detected on those objects is mostly crystalline.

  7. VizieR Online Data Catalog: Galilean moons & Jupiter positions (Narizhnaya, 2016)

    NASA Astrophysics Data System (ADS)

    Narizhnaya, N. V.

    2017-05-01

    Our observations were carried out with the Normal Astrograph (D/F=330mm/3467mm) at Pulkovo (code is 084). A (SBIG ST-L-11K 3) CCD camera was used as a detector (with a field of view of 35'x25' and a scale of 0.530"/pixel). The CCD_frames with object image were obtained by series including 10-20 images, depending on exposures of 10, 5 and 0.5 s, respectively. The IZMCCD software package developed by Izmailov I.S. (2005, http://iznccd.puldb.ru/ izmccdrus) was used in processing the CCD images. Astrometric reduction algorithm is based on Turner's method with using UCAC4 catalog as reference one. Ephemerides for comparison are given by web-server "Natural Satellites Ephemeride Server MULTI-SAT" developed by N.V. Emelyanov (http://lnfm1.sai.msu.ru/neb/nss/nssephmr.htm). Three catalogue are presented: 154 normal positions of Galilean satellites, 77 differential mutual coordinates of Galilean satellites and 47 Jupiter positions. (3 data files).

  8. What Does Galileo's Discovery of Jupiter's Moons Tell Us About the Process of Scientific Discovery?

    NASA Astrophysics Data System (ADS)

    Lawson, Anton E.

    In 1610, Galileo Galilei discovered Jupiter''smoons with the aid of a new morepowerful telescope of his invention. Analysisof his report reveals that his discoveryinvolved the use of at least three cycles ofhypothetico-deductive reasoning. Galileofirst used hypothetico-deductive reasoning to generateand reject a fixed star hypothesis.He then generated and rejected an ad hocastronomers-made-a-mistake hypothesis.Finally, he generated, tested, and accepted a moonhypothesis. Galileo''s reasoningis modeled in terms of Piaget''s equilibration theory,Grossberg''s theory of neurologicalactivity, a neural network model proposed by Levine &Prueitt, and another proposedby Kosslyn & Koenig. Given that hypothetico-deductivereasoning has played a rolein other important scientific discoveries, thequestion is asked whether it plays a rolein all important scientific discoveries. In otherwords, is hypothetico-deductive reasoningthe essence of the scientific method? Possiblealternative scientific methods, such asBaconian induction and combinatorial analysis,are explored and rejected as viablealternatives. Educational implications of thishypothetico-deductive view of scienceare discussed.

  9. Detecting Darwinism from Molecules in the Enceladus Plumes, Jupiter's Moons, and Other Planetary Water Lagoons

    PubMed Central

    2017-01-01

    Abstract To the astrobiologist, Enceladus offers easy access to a potential subsurface biosphere via the intermediacy of a plume of water emerging directly into space. A direct question follows: If we were to collect a sample of this plume, what in that sample, through its presence or its absence, would suggest the presence and/or absence of life in this exotic locale? This question is, of course, relevant for life detection in any aqueous lagoon that we might be able to sample. This manuscript reviews physical chemical constraints that must be met by a genetic polymer for it to support Darwinism, a process believed to be required for a chemical system to generate properties that we value in biology. We propose that the most important of these is a repeating backbone charge; a Darwinian genetic biopolymer must be a “polyelectrolyte.” Relevant to mission design, such biopolymers are especially easy to recover and concentrate from aqueous mixtures for detection, simply by washing the aqueous mixtures across a polycharged support. Several device architectures are described to ensure that, once captured, the biopolymer meets two other requirements for Darwinism, homochirality and a small building block “alphabet.” This approach is compared and contrasted with alternative biomolecule detection approaches that seek homochirality and constrained alphabets in non-encoded biopolymers. This discussion is set within a model for the history of the terran biosphere, identifying points in that natural history where these alternative approaches would have failed to detect terran life. Key Words: Enceladus—Life detection—Europa—Icy moon—Biosignatures—Polyelectrolyte theory of the gene. Astrobiology 17, 840–851. PMID:28665680

  10. Large impacts and tectonism: the relative ages of the basin Odysseus and Ithaca Chasma on Saturn's icy moon Tethys

    NASA Astrophysics Data System (ADS)

    Wagner, Roland; Stephan, Katrin; Schmedemann, Nico; Roatsch, Thomas; Kersten, Elke; Neukum, Gerhard; Denk, Tilmann; Porco, Carolyn C.

    2014-05-01

    Large impact events forming craters of basin size (> 200 - 300 km in diameter) on planets, asteroids or planetary satellites can cause intense tectonic deformation on their surfaces, indicated by concentric and/or radial troughs or ridges [e.g., 1]. Recently, sets of parallel grooves on asteroid (4) Vesta have been discussed to be the result of impact-related deformation in connection with basin-forming events on Vesta's south polar area [2]. On Saturn's mid-sized icy satellites Tethys, 1072 km in diameter, major landforms are the 445 km large impact basin Odysseus and the huge graben system of Ithaca Chasma which were first imaged during the Voyager encounters in 1980 and 1981 [3][4]. Ithaca Chasma is a ~100 km wide terraced trough. It has been discussed that Ithaca Chasma could be the result of structural deformation caused by the impact event that created Odysseus [4][5]. Preliminary mapping and crater counts using Cassini ISS imaging data on Odysseus and Ithaca Chasma, however, infer that this has not been the case [6]. Cassini VIMS spectral data show that Ithaca Chasma has less ice compared to Odysseus which supports this finding that it is older than the basin [7]. Major problems to exactly define the stratigraphic position of Ithaca Chasma with respect to the basin Odysseus are (1) that only those craters are allowed to be used for crater counts which clearly superimpose the tectonic structures (e.g., the terraced scarps) across the chasm, and (2) further geologic processes that affected the chasm interior caused obliteration of craters which results in lower crater frequencies. Our preliminary crater counts [6] were carried out on lower-resolution Cassini imaging data. During Cassini's orbital tour since July 2004, the ISS cameras have provided almost complete global image coverage of Tethys at resolutions of 100 - 300 m/pxl. In this work we present results from our ongoing studies on Tethys' geology, based on these new imaging data, primarily focused on

  11. Jupiter’s moon Europa

    NASA Image and Video Library

    2014-01-24

    This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features -- rising over 100 miles (160 kilometers) above Europa’s icy surface -- to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions.

  12. Jupiter Exploration: High Risk and High Rewards

    NASA Astrophysics Data System (ADS)

    Kite, Edwin S.

    2004-12-01

    Jupiter exploration is big science, and only the United States can afford self-contained missions to the gas giant and its four planet-sized moons. The Galileo spacecraft, which was recently flown into Jupiter to prevent it from contaminating Europa's ocean, cost $1.6 billion. Despite the failure of its High Gain Antenna (HGA), Galileo discovered briny, subsurface oceans on Europa, Ganymede, and Callisto; globally mapped all four Galilean moons; monitored Io's volcanic activity; carried out a 7-year study of the Jovian magnetosphere; and dropped an atmospheric probe into Jupiter's upper cloud layer. Of these achievements, the most significant is the indirect detection of a deep subsurface liquid-water layer on Europa [Pappalardo et al., 1999; Kivelson et al., 2000]. The case for a Europan ecosystem can be made [e.g., Marion et al., 2004], although it is important to remember the energetic and biogeochemical limits on putative Europan life [e.g., Soare et al., 2002]. Europa's low moment of inertia (0.346 +/- 0.005 MR2) suggests a silicate mantle below the ocean, permitting chemical exchanges between ocean and silicates, as occurs on Earth. Europa's surface is geologically young, likely emplaced 20-180 million years ago. Any recycling of surficial icy crust into the ocean could add oxygen, sulfur, and organic compounds, either impact-delivered or generated in situ by UV irradiation and the implantation of ionized particles from Jupiter's radiation belts.

  13. Laboratory permittivity measurements of icy planetary analogs in the millimeter and submillimeter domains, in relation with JUICE mission.

    NASA Astrophysics Data System (ADS)

    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

  14. Jupiter's Moon Ganymede

    NASA Image and Video Library

    This is a video clip of what Ganymede looks like, based on images from NASA's Galileo orbiter. The US Geological Survey has classified the surface of Ganymede into the types of terrain. The brown r...

  15. Surface-bounded Exospheres of the Icy Satellites

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.; Johnson, R. E.; Cooper, J. F.; Wong, M. C.

    2004-05-01

    Sputtering and radiolysis of the icy satellite surfaces are important sources of neutrals in the Jovian and Saturnian systems [1,2]. We have presented collisional Monte Carlo models of surface-bounded exospheres of the icy satellites in which the sublimation and sputtering sources of H2O molecules and their molecular fragments are accounted for as well as the physical and chemical exchange at the atmosphere-icy surface interface. Products of radiolytic interactions by more penetrating electrons and ions in the volume ice are incorporated into the sublimation source of escaping volatiles. The very tenuous hydrogen and oxygen exospheres originate from a balance between sources from irradiation of the icy satellite surface by solar UV photons and magnetospheric plasma and losses from pick-up ionization and ejection following dissociation or collisions with the low energy plasma ions. The surface-bounded exospheres of the icy satellites are characterized by the hot coronas formed due to atmospheric sputtering, by suprathermal radicals entering the regolith that can drive radiolytic chemistry, and by a supply of pick-up ions and neutrals into the surrounding planetary magnetosphere. This general picture of the surface-bounded exosphere formation is illustrated with calculations of the near-surface oxygen atmosphere of Europa and the supply rate of neutrals to the Europa's near-orbit torus[3]. The surface-bounded exosphere and neutral gas torus provide an extended region for the Jupiter Icy Moons Orbiter detection of neutrals and ions originating from Europa. [1] Johnson, R. E. 2002. Surface boundary layer atmospheres. In Atmospheres in the Solar System: Comparative Aeronomy (M. Mendillo, A. Nagy, J. H. Waite, Eds.) pp. 203-219. Geophys. Monograph, AGU. [2] Cooper, J.F., R.E. Johnson, B.H. Mauk, H.B. Garrett, and N. Gehrels 2001. Icarus 149(1), 133-159. [3] Shematovich, V.I., R.E. Johnson, J.F. Cooper, and M.C. Wong 2004, (submitted to Icarus).

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

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J. R.

    2006-03-01

    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 spacecraft on 2005 November 26. It is proposed that the moons had condensed from a concentric family of orbiting gas rings that were shed some 4.6 × 109 yr ago by the proto-Saturnian (hereafter p-Sat) cloud. The p-Sat cloud is made up of gas and residual grains of the gas ring that was shed by the proto-Solar cloud (hereafter PSC) at Saturn's orbit. The bulk of the condensate within this proto-Solar ring accumulates to form Saturn's central core of mass ~10-20 M ⊕ (M ⊕ = Earth mass). The process of formation of Saturn's solid core thus provides an opportunity for the p-Sat cloud to become depleted in rock and water ice relative to the usual solar abundances of these materials. Nitrogen, which exists as uncondensing N2 in the PSC and as NH3 in the p-Sat cloud, retains its solar abundance relative to H2. If the depletion factor of solids relative to gas is ζ dep = 0.25, as suggested by the low mass of Rhea relative to solar abundance expectations, the mass-percent ratio of NH3 to H2O in the dense p-Sat cloud is 36:64. Numerical and structural models for Rhea are constructed on the basis of a `cosmogonic' bulk chemical composition of hydrated rock (mass fraction 0.385), H2O ice (0.395), and NH3 ice (0.220). It is difficult to construct a chemically differentiated model of Rhea whose mean density matches the observed value ρ Rhea = 1.23 +/- 0.02 g cm-3 for reasonable bounds of the controlling parameters. Chemically homogeneous models can, however, be constrained to match the observed Rhea density provided that the mass fraction of NH3 is permitted to exceed the cosmogonic value by a factor ζ NH3 AS05041_E1.gifζNH3-> = 1.20-1.35. A large proportion of NH3 in the ice mass inhibits the formation of the dense crystalline phase II of H2O ice at high pressure. This may explain the lack of compressional features on the surface of the

  17. Europa's Icy Shell: A Bridge Between Its Surface and Ocean

    NASA Technical Reports Server (NTRS)

    Schenk, Paul; Mimmo, Francis; Prockter, Louise

    2004-01-01

    Europa, a Moon-sized, ice-covered satellite of Jupiter, is second only to Mars in its astrobiological potential. Beneath the icy surface, an ocean up to 150 km deep is thought to exist, providing a potential habitat for life,and a tempting target for future space missions. The Galileo mission to the Jovian system recently ended, but there are already long-range plans to send much more capable spacecraft,such as the proposed Jupiter Icy Moons Orbiter (JIMO), to take a closer look at Europa and her siblings, Ganymede and Callisto, some time in the next two decades. Europak outer icy shell is the only interface between this putative ocean and the surface, but many aspects of this shell are presently poorly understood; in particular, its composition, thickness, deformational history, and mechanical properties. To discuss the ice shell and our current understanding of it, 78 scientists from the terrestrial and planetary science communities in the United States and Europe gathered for a 3-day workshop hosted by the Lunar and Planetary Institute in Houston in February. A key goal was to bring researchers from disparate disciplines together to discuss the importance and limitations of available data on Europa with a post-Galileo perspective. The workshop featured 2 days of reviews and contributed talks on the composition, physical properties, stratigraphy, tectonics, and future exploration of the ice shell and underlying ocean. The final morning included an extended discussion period, moderated by a panel of noted experts, highlighting outstanding questions and areas requiring future research.

  18. Europa's Icy Shell: A Bridge Between Its Surface and Ocean

    NASA Technical Reports Server (NTRS)

    Schenk, Paul; Mimmo, Francis; Prockter, Louise

    2004-01-01

    Europa, a Moon-sized, ice-covered satellite of Jupiter, is second only to Mars in its astrobiological potential. Beneath the icy surface, an ocean up to 150 km deep is thought to exist, providing a potential habitat for life,and a tempting target for future space missions. The Galileo mission to the Jovian system recently ended, but there are already long-range plans to send much more capable spacecraft,such as the proposed Jupiter Icy Moons Orbiter (JIMO), to take a closer look at Europa and her siblings, Ganymede and Callisto, some time in the next two decades. Europak outer icy shell is the only interface between this putative ocean and the surface, but many aspects of this shell are presently poorly understood; in particular, its composition, thickness, deformational history, and mechanical properties. To discuss the ice shell and our current understanding of it, 78 scientists from the terrestrial and planetary science communities in the United States and Europe gathered for a 3-day workshop hosted by the Lunar and Planetary Institute in Houston in February. A key goal was to bring researchers from disparate disciplines together to discuss the importance and limitations of available data on Europa with a post-Galileo perspective. The workshop featured 2 days of reviews and contributed talks on the composition, physical properties, stratigraphy, tectonics, and future exploration of the ice shell and underlying ocean. The final morning included an extended discussion period, moderated by a panel of noted experts, highlighting outstanding questions and areas requiring future research.

  19. The Europa Jupiter system mission

    NASA Astrophysics Data System (ADS)

    Clark, K.; Stankov, A.; Pappalardo, R. T.; Greeley, R.; Blanc, M.; Lebreton, J.-P.; van Houten, T.

    2009-04-01

    Europa Jupiter System Mission (EJSM)— would be an international mission that would achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA 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 be-fore settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupi-ter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and charac-terize water oceans beneath the ice shells of Europa and Ganymede. EJSM would fully addresses high priority science objectives identified by the National Research Coun-cil's (NRC's) Decadal Survey and ESA's Cosmic Vi-sion for exploration of the outer solar system. The De-cadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission tar-get. EJSM would uniquely addresse several of the cen-tral themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM would investigate the potential habitability of the active ocean-bearing moons Europa and Gany-mede, detailing the geophysical, compositional, geo-logical, and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupi-ter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant plan-ets and their satellites would be

  20. The Europa Jupiter System Mission

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Clark, K.; Erd, C.; Pappalardo, R.; Greeley, R. R.; Blanc, M.; Lebreton, J.; van Houten, T.

    2009-05-01

    Europa Jupiter System Mission (EJSM) will be an international mission that will achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA 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). The JEO mission has been selected by NASA as the next Flagship mission to the out solar system. JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupiter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. EJSM will fully addresses high priority science objectives identified by the National Research Council's (NRC's) Decadal Survey and ESA's Cosmic Vision for exploration of the outer solar system. The Decadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission target. EJSM would uniquely address several of the central themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM will investigate the potential habitability of the active ocean-bearing moons Europa and Ganymede, detailing the geophysical, compositional, geological and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the

  1. Shepherd Moons

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Shepherd Moons

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter in February 2007. This sequence of pictures from the Long Range Reconnaissance Imager (LORRI) shows the well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings; labels point out how these narrow rings are confined in their orbits by small 'shepherding' moons (Metis and Adrastea).

  2. Jupiter Atmospheric Science with JIMO: Linking Science Objectives and Measurement Goals

    NASA Technical Reports Server (NTRS)

    Chanover, N. J.; Glenar, D. A.; Simon-Miller, A. A.

    2003-01-01

    Although the primary focus of the Jupiter Icy Moons Orbiter (JIMO) mission will be the characterization and study of Jupiter's icy moons, there will be opportunities throughout the mission for unprecendented observations of Jupiter. With an adaptable suite of payload instruments, the atmospheric data collected by JIMO can help to answer fundamental questions about the largest planet in our solar system that remain after (or were generated by) previous spacecraft reconnaissance (e.g. Voyager, Galileo, and Cassini). Near-IR (0.7-4 micron) spectral imaging will most likely be used to identify mineralogies and ices on the Jovian satellites by virtue of their spectral signatures. This same capability is very well tailored for studies of Jovian atmospheric dynamics and structure. Near-IR methane absorption bands allow 2-D mapping of the horizontal wind field at size scales to tens of kms, as well as the height dependence of this field above the ammonia cloud deck (700 to a few mbar), constraining current models of atmospheric vertical structure. Likewise, atmospheric ice aerosols with unique spectroscopic signatures (ammonia ice near 1.5, 2.0, and 2.8 microns and water ice between 3.0 - 3.5 microns) can be detected and mapped using spectral difference imaging or spectrally inclusive principal-component methods. Spectral imaging of the Jovian aurora via (3)H(+) emission lines between 3 - 4 microns can be used to spatially map the interplay between the satellites) Jupiter's magnetosphere, and Jupiter's atmosphere. Each of these measurements addresses one or more fundamental questions related to the energy balance in Jupiter's atmosphere. All of these tunable imaging objectives can be achieved using acousto-optic tunable filters (AOTF's), which have been used for years in ground-based observing instruments and which have been proposed for numerous planetary missions. The application of this technology to the science objectives of both the icy satellites and Jovian

  3. ICIS Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  4. Jupiter's snowball

    NASA Astrophysics Data System (ADS)

    Friebele, Elaine

    Recent observations from NASA's Galileo spacecraft reveal that Callisto, one of Jupiter's sixteen moons, is like an undifferentiated “dirty snowball” that has no internal magnetic field or magnetosphere. The outermost of the four large moons discovered by Galileo may be enshrouded by a tenuous atmosphere, however. The new findings, reported in the latest issue of Nature, are surprising because earlier data from Galileo indicates that two of Jupiter's other Galilean moons—Ganymede and Io—have magnetic fields. John D. Anderson of the Jet Propulsion Laboratory in Pasadena, Calif., and colleagues presented gravimetric data showing that Callisto is composed of 40% compressed ice and 60% rock mixed with metal. The undifferentiated composition is consistent with the absence of a magnetic field, which was confirmed by Krishan Khurana of the University of California and his colleagues.

  5. Coupling of the Matched Gravity and Electromagnetic Fields of the Sun with Jupiter and its Moons Together in Nearest Portion of Jupiter's Orbit to the Sun as the Main Cause of the Peak of Approximately 11 Yearly Solar Cycles and Hazards from Solar Storms

    NASA Astrophysics Data System (ADS)

    Gholibeigian, Kazem; Gholibeigian, Hassan

    2016-04-01

    On March 13, 1989 the entire province of Quebec Blackout by solar storm during solar cycle 22. The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm during solar cycle 10. The solar storm of 2012 during solar cycle 24 was of similar magnitude, but it passed Earth's orbit without striking the plane. All of these solar storms occurred in the peak of 11 yearly solar cycles. In this way, the White House in its project which is focusing on hazards from solar system, in a new strategy and action plan to increase protection from damaging solar emissions, should focus on coupling of the matched Gravity and Electromagnetic Fields)GEFs) of the Sun with Jupiter and its moons together. On the other hand, in solar system, the Jupiter's gravity has largest effect to the Sun's core and its dislocation, because the gravity force between the Jupiter and the Sun is 11.834 times, In addition overlapping of the solar cycles with the Jupiter's orbit period is 11.856 years. These observable factors lead us to the effect of the Jupiter and Sun gravity fields coupling as the main cause of the approximately 11 years duration for solar cycles. Its peak in each cycle is when the Jupiter is in nearest portion to the Sun in its orbit. In this way, the other planets in their coupling with Sun help to the variations and strengthening solar cycles. [Gholibeigian, 7/24/2015http://adsabs.harvard.edu/abs/2014EGU]. In other words, the both matched GEFs are generating by the large scale forced convection system inside the stars and planets [Gholibeigian et. al, AGU Fall Meeting 2015]. These two fields are couple and strengthening each other. The Jupiter with its 67 moons generate the largest coupled and matched GEFs in its core and consequently strongest effect on the Sun's core. Generation and coupling of the Jupiter's GEFs with its moons like Europa, Io and Ganymede make this planet of thousands of times brighter and many times bigger than Earth as the

  6. Earth Moon

    NASA Image and Video Library

    1998-06-08

    NASA Galileo spacecraft took this image of Earth moon on December 7, 1992 on its way to explore the Jupiter system in 1995-97. The distinct bright ray crater at the bottom of the image is the Tycho impact basin. http://photojournal.jpl.nasa.gov/catalog/PIA00405

  7. Experimental determination of salt partition coefficients between aqueous fluids, ice VI and ice VII: implication for the composition of the deep ocean and the geodynamics of large icy moons and water rich planets

    NASA Astrophysics Data System (ADS)

    Journaux, Baptiste; Daniel, Isabelle; Cardon, Hervé; Petitgirard, Sylvain; Perrillat, Jean-Philippe; Caracas, Razvan; Mezouar, Mohamed

    2015-04-01

    The potential habitability of extraterrestrial large aqueous reservoir in icy moons and exoplanets requires an input of nutrients and chemicals that may come from the rocky part of planetary body. Because of the presence of high pressure (HP) water ices (VI, VII, etc.) between the liquid ocean and the silicates, such interactions are considered to be limited in large icy moons, like Ganymede and Titan, and water rich exoplanets. In the case of salty-rich oceans, recent experimental and modeling works have shown that aqueous fluids can be stable at higher pressures [1, 2]. This can ultimately allow direct interaction with the rocky core of icy moons. This effect is nevertheless limited and for larger bodies such as water rich exoplanets with much higher pressures in their hydrosphere, HP ice should be present between the rocky core and a putative ocean. Salts are highly incompatible with low pressure ice Ih, but recent experimental work has shown that alkali metal and halogen salts are moderately incompatible with ice VII, that can incorporate up to several mol/kg of salts [3, 4, 5]. As far as we know, no similar study has been done on ice VI, a HP ice phase expected inside large icy moons. We present here the first experimental data on the partition coefficient of RbI salt between aqueous fluids, ice VI and ice VII using in-situ synchrotron X-Ray single crystal diffraction and X-Ray fluorescence mapping (ESRF - ID-27 beam line [6]). Our experiment enable us to observe a density inversion between ice VI and the salty fluid, and to measure the values of salt partition coefficients between the aqueous fluid and ice VI (strongly incompatible) and ice VII (moderately incompatible). Using the volumes determined with X-Ray diffraction, we were able to measure the density of salty ice VI and ice VII and determine that salty ice VI is lighter than pure H2O ice VI. These results are very relevant for the study of water rich planetary bodies interior because the partition

  8. PHOTO ILLUSTRATION OF COMET P/SHOEMAKER-LEVY 9 and PLANET JUPITER

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a composite photo, assembled from separate images of Jupiter and comet P/Shoemaker-Levy 9, as imaged by the Wide Field and Planetary Camera-2 (WFPC-2), aboard NASA's Hubble Space Telescope (HST). Jupiter was imaged on May 18, 1994, when the giant planet was at a distance of 420 million miles (670 million km) from Earth. This 'true-color' picture was assembled from separate HST exposures in red, blue, and green light. Jupiter's rotation between exposures creates the blue and red fringe on either side of the disk. HST can resolve details in Jupiter's magnificent cloud belts and zones as small as 200 miles (320 km) across (wide field mode). This detailed view is only surpassed by images from spacecraft that have traveled to Jupiter. The dark spot on the disk of Jupiter is the shadow of the inner moon Io. This volcanic moon appears as an orange and yellow disk just to the upper right of the shadow. Though Io is approximately the size of Earth's Moon (but 2,000 times farther away), HST can resolve surface details. When the comet was observed on May 17, its train of 21 icy fragments stretched across 710 thousand miles (1.1 million km) of space, or 3 times the distance between Earth and the Moon. This required six WFPC exposures along the comet train to include all the nuclei. The image was taken in red light. The apparent angular size of Jupiter relative to the comet, and its angular separation from the comet when the images were taken, have been modified for illustration purposes. Credit: H.A. Weaver, T.E. Smith (Space Telescope Science Institute) and J.T. Trauger, R.W. Evans (Jet Propulsion Laboratory), and NASA

  9. PHOTO ILLUSTRATION OF COMET P/SHOEMAKER-LEVY 9 and PLANET JUPITER

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a composite photo, assembled from separate images of Jupiter and comet P/Shoemaker-Levy 9, as imaged by the Wide Field and Planetary Camera-2 (WFPC-2), aboard NASA's Hubble Space Telescope (HST). Jupiter was imaged on May 18, 1994, when the giant planet was at a distance of 420 million miles (670 million km) from Earth. This 'true-color' picture was assembled from separate HST exposures in red, blue, and green light. Jupiter's rotation between exposures creates the blue and red fringe on either side of the disk. HST can resolve details in Jupiter's magnificent cloud belts and zones as small as 200 miles (320 km) across (wide field mode). This detailed view is only surpassed by images from spacecraft that have traveled to Jupiter. The dark spot on the disk of Jupiter is the shadow of the inner moon Io. This volcanic moon appears as an orange and yellow disk just to the upper right of the shadow. Though Io is approximately the size of Earth's Moon (but 2,000 times farther away), HST can resolve surface details. When the comet was observed on May 17, its train of 21 icy fragments stretched across 710 thousand miles (1.1 million km) of space, or 3 times the distance between Earth and the Moon. This required six WFPC exposures along the comet train to include all the nuclei. The image was taken in red light. The apparent angular size of Jupiter relative to the comet, and its angular separation from the comet when the images were taken, have been modified for illustration purposes. Credit: H.A. Weaver, T.E. Smith (Space Telescope Science Institute) and J.T. Trauger, R.W. Evans (Jet Propulsion Laboratory), and NASA

  10. Two-Body Approximations in the Design of Low-Energy Transfers Between Galilean Moons

    NASA Astrophysics Data System (ADS)

    Fantino, Elena; Castelli, Roberto

    Over the past two decades, the robotic exploration of the Solar System has reached the moons of the giant planets. In the case of Jupiter, a strong scientific interest towards its icy moons has motivated important space missions (e.g., ESAs' JUICE and NASA's Europa Mission). A major issue in this context is the design of efficient trajectories enabling satellite tours, i.e., visiting the several moons in succession. Concepts like the Petit Grand Tour and the Multi-Moon Orbiter have been developed to this purpose, and the literature on the subject is quite rich. The models adopted are the two-body problem (with the patched conics approximation and gravity assists) and the three-body problem (giving rise to the so-called low-energy transfers, LETs). In this contribution, we deal with the connection between two moons, Europa and Ganymede, and we investigate a two-body approximation of trajectories originating from the stable/unstable invariant manifolds of the two circular restricted three body problems, i.e., Jupiter-Ganymede and Jupiter-Europa. We develop ad-hoc algorithms to determine the intersections of the resulting elliptical arcs, and the magnitude of the maneuver at the intersections. We provide a means to perform very fast and accurate evaluations of the minimum-cost trajectories between the two moons. Eventually, we validate the methodology by comparison with numerical integrations in the three-body problem.

  11. Japanese mission plan for Jupiter system: The Jupiter magnetospheric orbiter and the Trojan asteroid explorer

    NASA Astrophysics Data System (ADS)

    Sasaki, S.; Fujimoto, M.; Yano, H.; Takashima, T.; Kasaba, Y.; Takahashi, Y.; Kimura, J.; Funase, R.; Mori, O.; Tsuda, Y.; Campagnola, S.; Kawakatsu, Y.

    2011-10-01

    In the future Jupiter system study, Coordinated observation of Jovian magnetosphere is one of the important targets of the mission in addition to icy satellites, atmosphere, and interior of Jupiter. JAXA will take a role on the magnetosphere spinner JMO (Jupiter Magnetospheric Orbiter), in addition to JGO (Jupiter Ganymede Orbiter) by ESA and JEO (Jupiter Europa Orbiter) by NASA. We will combine JMO with a proposed solar sail mission of JAXA for Jupiter and one of Trojan asteroids. Since Trojan asteroids could be representing raw solid materials of Jupiter or at least outer solar system bodies, involvement of Trojan observation should enhance the quality of Jupiter system exploration.

  12. The Diversity of Icy Ocean Worlds (Invited)

    NASA Astrophysics Data System (ADS)

    Hussmann, H.

    2010-12-01

    The idea that several of the outer planet satellites might contain subsurface water oceans was first proposed by Lewis (1971) and others in the early seventies. Since the late nineties, evidence for the presence of those liquid layers was provided by the Galileo mission for Europa, Ganymede, and Callisto and by Cassini data for Saturn’s moon Enceladus. Modelling suggests that furthermore Saturn’s moon Titan, Neptune’s Triton, and other large icy objects in the outer solar system can contain liquid water layers in their interiors. Thus, subsurface water oceans in icy moons and presumably in Kuiper-belt binaries might provide habitable environments in the outer solar system. Long-term stability of the oceans requires energy sources that provide sufficient heat to maintain liquid layers on geologic time-scales. On the other hand the rate of heat transport has to be sufficiently small to prevent the oceans from freezing. Both competing factors depend on the physical properties (e.g., rock content, interior structure, temperature) of the satellite and —in some cases— on the interaction with other planetary bodies (e.g., tidal interaction with the primary and resonances with other satellites). Furthermore, the presence of oceans depends on chemical properties (e.g., volatile content) of the liquid phase and is thus closely linked to the conditions in the respective sub-nebula during accretion. The resulting conditions for a putative ocean may vary considerably for the individual satellites. As a consequence expected ocean worlds will be very diverse in the outer solar system. Here we discuss the conditions under which liquid water layers can be maintained on long time-scales. Energy sources and processes that play a key role, i.e. radioactive decay, tidal heating, energy due to accretion and differentiation will be estimated in application to the satellites of Jupiter, Saturn, Uranus and Neptune. In case of tidal heating, the resulting heat balance equation can

  13. Melting probes as a means to access the subsurface of Mars' polar caps and Jupiter's ice moons

    NASA Astrophysics Data System (ADS)

    Biele, J.; Ulamec, S.; Funke, O.; Engelhardt, M.

    There is a high scientific interest in exploring certain planetary icy environments in the solar system (Mars' polar caps, Europa and other icy satellites) motivated by the search for traces of life in these extreme environments as well as interest in planetary climate history as in the case of Mars. A promising technique to penetrate thick ice layers with small and reliable probes which do not require the heavy, complex and expensive equipment of a drilling rig is by melting. Contamination avoidance with respect to planetary protection requirements can be fulfilled using melting probes, since the melting channel refreezes behind the probe and shuts off the contact to the surface; also, in-situ decontamination of the probe is possible. Melting probes can be equipped with a suite of scientific instruments that are capable e.g. of determining the chemical and isotopic composition of the embedded or dissolved materials, of the ices themselves, of the dust content and possible traces of indigenous biological activity. Due to the still rather high energy demand to overcome the melting enthalpy, in case of extraterrestrial application (e.g. Europa or polar caps of Mars), only heating with radioactive isotopes seems feasible for reaching greater depths. The necessary power is driven by the desired penetration velocity (linearly) and the dimensions of the probe (proportional to the cross section). On Mars, however, solar cells could be used to power small tethered melting probes in polar summer. While such probes have successfully been used for terrestrial applications, e.g., in Antarctica in the 1990ies, the technology is not yet mature for space applications; for example, the behaviour in vacuum (below the triple point pressure of water, i.e., 611 Pa) needs to be assessed. We will report briefly on our laboratory tests with melting probes in vacuum and under very low temperatures to this end. Practical issues (impact of dust on the performance, gravity dependence

  14. Scientists Revise Thinking on Comets, Planet Jupiter

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Discusses scientific information obtained from Pioneer 10's Jupiter flyby and the comet Kohoutek's first trip around the sun, including the high hydrogen emission of Jupiter's principal moon, Io. (CC)

  15. Scientists Revise Thinking on Comets, Planet Jupiter

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Discusses scientific information obtained from Pioneer 10's Jupiter flyby and the comet Kohoutek's first trip around the sun, including the high hydrogen emission of Jupiter's principal moon, Io. (CC)

  16. Icy Hydra

    NASA Image and Video Library

    2016-05-06

    The surface of Hydra, Pluto outermost small moon, is dominated by nearly pristine water ice confirming hints that scientists picked up in NASA New Horizons images showing Hydra highly reflective surface.

  17. Measuring the speed of light using Jupiter's moons: a global citizen science project for International Year of Light 2015

    NASA Astrophysics Data System (ADS)

    Hendry, Martin A.; Hammond, Giles; Simmons, Mike

    2015-08-01

    2015 represents both the centenary of General Relativity and International Year of Light - the latter marking the 150th anniversary of James Clerk Maxwell's ground-breaking paper on "A dynamical theory of the electromagnetic field". These landmark dates provide an exciting opportunity to set up a global citizen science project that re-enacts the seminal 1675 experiment of Ole Romer: to measure the speed of light by observing the time eclipses of the satellites of Jupiter. This project - which has been set up by astronomers at the University of Glasgow, UK in partnership with Astronomers without Borders - is an ideal platform for engaging the amateur astronomy community, schools and the wider public across the globe. It requires only simple observations, with a small spotting scope or telescope, and can be carried out straightforwardly in both cities and dark-sky locations. It highlights a fascinating chapter in astronomical history, as well as the ongoing importance of accurate astrometry, orbital motion, the concept of longitude and knowing one's position on the Earth. In the context of the GR centenary, it also links strongly to the science behind GPS satellites and a range of important topics in the high school curriculum - from the electromagnetic spectrum to the more general principles of the scientific method.In this presentation we present an overview of our global citizen science project for IYL2015: its scope and motivation, the total number and global distribution of its participants to date and how astronomers around the world can get involved. We also describe the intended legacy of the project: a extensive database of observations that can provide future astronomy educators with an accessible and historically important context in which to explore key principles for analysing large astronomical datasets.

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

    NASA Astrophysics Data System (ADS)

    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

  19. The Jupiter System Observer: Probing the Foundations of Planetary Systems

    NASA Astrophysics Data System (ADS)

    Senske, D.; Prockter, L.; Collins, G.; Cooper, J.; Hendrix, A.; Hibbitts, K.; Kivelson, M.; Orton, G.; Schubert, G.; Showman, A.; Turtle, E.; Williams, D.; Kwok, J.; Spilker, T.; Tan-Wang, G.

    2007-12-01

    Galileo's observations in the 1600's of the dynamic system of Jupiter and its moons launched a revolution in understanding the way planetary systems operate. Now, some 400 years later, the discovery of extra solar planetary systems with Jupiter-sized bodies has led to a similar revolution in thought regarding how these systems form and evolve. From the time of Galileo, the Jovian system has been viewed as a solar system in miniature, providing a laboratory to study, diverse and dynamic processes in a single place. The icy Galilean satellites provide a window into solar system history by preserving in their cratering records a chronology dating back nearly 4.5 By and extending to the present. The continuously erupting volcanoes of Io may provide insight into the era when magma oceans were common. The discovery of an internally generated magnetic field at Ganymede, one of only three terrestrial bodies to possess such a field, is a place to gain insight as to how dynamos work. The confirmation and characterization of icy satellite subsurface oceans impacts the way habitability is considered. Understanding the composition and volatile inventory of Jupiter can shed light into how planets accrete from the solar nebulae. Finally, like our sun, Jupiter influences its system through its extensive magnetic field. In early 2007, NASA's Science Mission Directorate formed four Science Definition Teams (SDTs) to formulate science goals and objectives in anticipation of the initiation of a flagship-class mission to the outer solar system (Europa, Jupiter system, Titan and Enceladus). The Jupiter System Observer (JSO) mission concept emphasizes overall Jupiter system science: 1) Jupiter and its atmosphere, 2) the geology and geophysics of the Galilean satellites (Io, Europa, Ganymede and Callisto), 3) the magnetosphere environment - both Jupiter's and Ganymede's&pand 4) interactions within the system. Focusing on the unique geology, presence of an internal magnetic field and

  20. Galileo's Medicean Moons (IAU S269)

    NASA Astrophysics Data System (ADS)

    Barbieri, Cesare; Chakrabarti, Supriya; Coradini, Marcello; Lazzarin, Monica

    2010-11-01

    Preface; 1. Galileo's telescopic observations: the marvel and meaning of discovery George V. Coyne, S. J.; 2. Popular perceptions of Galileo Dava Sobel; 3. The slow growth of humility Tobias Owen and Scott Bolton; 4. A new physics to support the Copernican system. Gleanings from Galileo's works Giulio Peruzzi; 5. The telescope in the making, the Galileo first telescopic observations Alberto Righini; 6. The appearance of the Medicean Moons in 17th century charts and books. How long did it take? Michael Mendillo; 7. Navigation, world mapping and astrometry with Galileo's moons Kaare Aksnes; 8. Modern exploration of Galileo's new worlds Torrence V. Johnson; 9. Medicean Moons sailing through plasma seas: challenges in establishing magnetic properties Margaret G. Kivelson, Xianzhe Jia and Krishan K. Khurana; 10. Aurora on Jupiter: a magnetic connection with the Sun and the Medicean Moons Supriya Chakrabarti and Marina Galand; 11. Io's escaping atmosphere: continuing the legacy of surprise Nicholas M. Schneider; 12. The Jovian Rings Wing-Huen Ip; 13. The Juno mission Scott J. Bolton and the Juno Science Team; 14. Seeking Europa's ocean Robert T. Pappalardo; 15. Europa lander mission: a challenge to find traces of alien life Lev Zelenyi, Oleg Korablev, Elena Vorobyova, Maxim Martynov, Efraim L. Akim and Alexander Zakahrov; 16. Atmospheric moons Galileo would have loved Sushil K. Atreya; 17. The study of Mercury Louise M. Prockter and Peter D. Bedini; 18. Jupiter and the other giants: a comparative study Thérèse Encrenaz; 19. Spectroscopic and spectrometric differentiation between abiotic and biogenic material on icy worlds Kevin P. Hand, Chris McKay and Carl Pilcher; 20. Other worlds, other civilizations? Guy Consolmagno, S. J.; 21. Concluding remarks Roger M. Bonnet; Posters; Author index; Object index.

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

    NASA Astrophysics Data System (ADS)

    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

  2. Very High Resolution Image of Icy Cliffs on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image, taken by the camera onboard NASA's Galileo spacecraft, is a very high resolution view of the Conamara Chaos region on Jupiter's moon Europa. It shows an area where icy plates have been broken apart and moved around laterally. The top of this image is dominated by corrugated plateaus ending in icy cliffs over a hundred meters (a few hundred feet) high. Debris piled at the base of the cliffs can be resolved down to blocks the size of a house. A fracture that runs horizontally across and just below the center of the Europa image is about the width of a freeway.

    North is to the top right of the image, and the sun illuminates the surface from the east. The image is centered at approximately 9 degrees north latitude and 274 degrees west longitude. The image covers an area approximately 1.7 kilometers by 4 kilometers (1 mile by 2.5 miles). The resolution is 9 meters (30 feet) per picture element. This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by Galileo's solid state imaging system.

    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.

  3. The icy Jovian satellites after the Galileo mission

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    2010-03-01

    The icy satellites of Jupiter, Callisto, Ganymede, Europa and Amalthea have diverse and remarkable characteristics. Their initial compositions were determined by conditions in the circum-Jovian nebula, just as the planets' initial properties were governed by their formation within the circumsolar nebula. The satellites subsequently evolved under the complex interplay of orbital and geophysical processes, especially the effects of orbital resonances, tides, internal differentiation and heat. The history and character of the satellites can be inferred from consideration of the formation of planets and the satellites, from studies of their plausible orbital evolution, from measurements of geophysical properties, especially gravitational and magnetic fields, from observations of the compositions and geological structure of their surfaces and from theoretical modeling of the processes that connect these lines of evidence. The three large icy satellites probably contain significant liquid water: Europa has a deep liquid water ocean under a thin surface layer of ice; Ganymede and Callisto likely have relatively thin liquid water layers deep below their surfaces. Models of formation are challenged by the surprising properties of the outermost and innermost of the group: Callisto is partially differentiated, with rock and ice mixed through much of its interior; and tiny Amalthea also appears to be largely composed of ice. Each of the four moons is fascinating in its own right, and the ensemble provides a powerful set of constraints on the processes that led to their formation and evolution.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Phase relations between the water-rich sulfuric acid hydrates, potential markers of thermal history on Jupiter’s icy moons

    NASA Astrophysics Data System (ADS)

    Maynard-Casely, H. E.; Brand, H. E. A.; Wallwork, K. S.

    2014-08-01

    Synchrotron X-ray powder diffraction has been used to explore the water-rich (<50 wt.% H2SO4) region of the sulfuric acid and water binary phase diagram at temperatures between 80 and 285 K. The phase relations that are determined demonstrate that, on laboratory timescales, sulfuric acid hydrates crystallize as mixtures of phases. Four forms of sulfuric acid hydrates were observed along with ice Ih, with their proportions dependent on temperature and sample H2SO4 wt.%. The charting of these phase relations has revealed a transformation between hydrate forms, which could be utilized as a marker for areas of higher heat flow on the surfaces of the Galilean ice moons.

  6. Outer planets and icy satellites

    NASA Technical Reports Server (NTRS)

    Drobyshevski, E. M.

    1991-01-01

    The resources offered by the outer bodies in the Solar System, starting with the main belt asteroids and Jovian System, are not only larger and more diverse but may even be easier to reach than, say, those of Mars. The use of their material, including water and organic matter, depends exclusively on the general strategy of exploration of the Solar System. Of major interest in this respect are the large ice satellites - Titan, Ganymede, and Callisto. Motion through the planetary magnetospheres excites in their ice envelopes megampere currents which, in the presence of rocky, etc., inclusions with electronic conduction should lead to the bulk electrolysis of ice and accumulation in it of 2H2 + O2 in the form of a solid solution. With the concentration of 2H2 + O2 reaching about 15 wt. percent, the solution becomes capable of detonation by a strong meteoritic impact. An explosion of Ganymede's ice envelope about 0.5 By ago could account for the formation of the Trojans and irregular satellites, all known differences between Ganymede and Callisto, and many other things. The explosion of a small icy planet with M approx less than 0.5 Moon created the asteroid belt. Two to three explosions occurred on Io, and two on Europa. The specific features of the longperiod comets close to Saturn's orbit permit dating Titan's envelope explosion as 10,000 yr ago, which produced its thick atmosphere, young Saturn's rings, as well as a reservoir of ice fragments saturated by 2H2 + O2, i.e., cometary nuclei between the orbits of Jupiter and Saturn. Thus these nuclei should contain, besides organic matter, also 2H2 + O2, which could be used for their transportation as well as for fuel for spaceships. Ices of such composition can reside deep inside Deimos, the Trojans, C-asteroids, etc. The danger of a future explosion of Callisto's electrolyzed ices, which would result in a catastrophic bombardment of the Earth by comets, may be high enough to warrant a revision of the priorities and

  7. Outer planets and icy satellites

    NASA Technical Reports Server (NTRS)

    Drobyshevski, E. M.

    1991-01-01

    The resources offered by the outer bodies in the Solar System, starting with the main belt asteroids and Jovian System, are not only larger and more diverse but may even be easier to reach than, say, those of Mars. The use of their material, including water and organic matter, depends exclusively on the general strategy of exploration of the Solar System. Of major interest in this respect are the large ice satellites - Titan, Ganymede, and Callisto. Motion through the planetary magnetospheres excites in their ice envelopes megampere currents which, in the presence of rocky, etc., inclusions with electronic conduction should lead to the bulk electrolysis of ice and accumulation in it of 2H2 + O2 in the form of a solid solution. With the concentration of 2H2 + O2 reaching about 15 wt. percent, the solution becomes capable of detonation by a strong meteoritic impact. An explosion of Ganymede's ice envelope about 0.5 By ago could account for the formation of the Trojans and irregular satellites, all known differences between Ganymede and Callisto, and many other things. The explosion of a small icy planet with M approx less than 0.5 Moon created the asteroid belt. Two to three explosions occurred on Io, and two on Europa. The specific features of the longperiod comets close to Saturn's orbit permit dating Titan's envelope explosion as 10,000 yr ago, which produced its thick atmosphere, young Saturn's rings, as well as a reservoir of ice fragments saturated by 2H2 + O2, i.e., cometary nuclei between the orbits of Jupiter and Saturn. Thus these nuclei should contain, besides organic matter, also 2H2 + O2, which could be used for their transportation as well as for fuel for spaceships. Ices of such composition can reside deep inside Deimos, the Trojans, C-asteroids, etc. The danger of a future explosion of Callisto's electrolyzed ices, which would result in a catastrophic bombardment of the Earth by comets, may be high enough to warrant a revision of the priorities and

  8. Outer planets and icy satellites

    NASA Astrophysics Data System (ADS)

    Drobyshevski, E. M.

    The resources offered by the outer bodies in the Solar System, starting with the main belt asteroids and Jovian System, are not only larger and more diverse but may even be easier to reach than, say, those of Mars. The use of their material, including water and organic matter, depends exclusively on the general strategy of exploration of the Solar System. Of major interest in this respect are the large ice satellites - Titan, Ganymede, and Callisto. Motion through the planetary magnetospheres excites in their ice envelopes megampere currents which, in the presence of rocky, etc., inclusions with electronic conduction should lead to the bulk electrolysis of ice and accumulation in it of 2H2 + O2 in the form of a solid solution. With the concentration of 2H2 + O2 reaching about 15 wt. percent, the solution becomes capable of detonation by a strong meteoritic impact. An explosion of Ganymede's ice envelope about 0.5 By ago could account for the formation of the Trojans and irregular satellites, all known differences between Ganymede and Callisto, and many other things. The explosion of a small icy planet with M approx less than 0.5 Moon created the asteroid belt. Two to three explosions occurred on Io, and two on Europa. The specific features of the longperiod comets close to Saturn's orbit permit dating Titan's envelope explosion as 10,000 yr ago, which produced its thick atmosphere, young Saturn's rings, as well as a reservoir of ice fragments saturated by 2H2 + O2, i.e., cometary nuclei between the orbits of Jupiter and Saturn. Thus these nuclei should contain, besides organic matter, also 2H2 + O2, which could be used for their transportation as well as for fuel for spaceships. Ices of such composition can reside deep inside Deimos, the Trojans, C-asteroids, etc. The danger of a future explosion of Callisto's electrolyzed ices, which would result in a catastrophic bombardment of the Earth by comets, may be high enough to warrant a revision of the priorities and

  9. Larger Icy Satellites

    NASA Astrophysics Data System (ADS)

    Vance, Steven; Buratti, B. J.; Hansen, C.; Hurford, T.; McKinnon, W. B.; Pappalardo, R. T.; Turtle, E. P.

    2009-09-01

    Outer planets exploration in the past three decades has revealed a diverse host of large icy bodies undergoing a myriad of geological and chemical processes remarkably similar yet alien to those occurring on Earth. The most active of these, including the Galilean satellites and Saturn's moons Enceladus and Titan, are obvious targets for future robotic exploration. The broader host of satellites larger than 100 km should also figure into NASA's goals, owing to their abundance and insights they offer into past and present geological processes, Solar System formation and planetary evolution. Included in this class are the enigmatic objects Dione, with its smooth planes and fractured regions; Mimas with its giant crater Herschel; Iapetus, which has an odd shape and a mysterious equatorial ridge; Miranda, which has been subjected to drastic geologic reconfiguration; and Triton, with its geyser-like plumes. Many bodies in this class are of sufficient size and density to have hosted internal liquid water oceans in their early history, or even in the present epoch, making them targets of astrobiological interest. We discuss the importance of larger icy satellites to NASA's objectives, their importance for understanding, geology, chemistry and dynamics in the Solar System, and observational and experimental challenges that need to be addressed in the next decade.

  10. Juno on Jupiter Doorstep

    NASA Image and Video Library

    2016-06-24

    NASA's Juno spacecraft obtained this color view on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter. As Juno makes its initial approach, the giant planet's four largest moons -- Io, Europa, Ganymede and Callisto -- are visible, and the alternating light and dark bands of the planet's clouds are just beginning to come into view. Juno is approaching over Jupiter's north pole, affording the spacecraft a unique perspective on the Jupiter system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet's equator. The scene was captured by the mission's imaging camera, called JunoCam, which is designed to acquire high resolution views of features in Jupiter's atmosphere from very close to the planet. http://photojournal.jpl.nasa.gov/catalog/PIA20701

  11. Plume Collection Strategies for Icy World Sample Return

    NASA Technical Reports Server (NTRS)

    Neveu, M.; Glavin, D. P.; Tsou, P.; Anbar, A. D.; Williams, P.

    2015-01-01

    Three icy worlds in the solar system display evidence of pluming activity. Water vapor and ice particles emanate from cracks near the south pole of Saturn's moon Enceladus. The plume gas contains simple hydrocarbons that could be fragments of larger, more complex organics. More recently, observations using the Hubble and Herschel space telescopes have hinted at transient water vapor plumes at Jupiter's moon Europa and the dwarf planet Ceres. Plume materials may be ejected directly from possible sub-surface oceans, at least on Enceladus. In such oceans, liquid water, organics, and energy may co-exist, making these environments habitable. The venting of habitable ocean material into space provides a unique opportunity to capture this material during a relatively simple flyby mission and return it to Earth. Plume collection strategies should enable investigations of evidence for life in the returned samples via laboratory analyses of the structure, distribution, isotopic composition, and chirality of the chemical components (including biomolecules) of plume materials. Here, we discuss approaches for the collection of dust and volatiles during flybys through Enceladus' plume, based on Cassini results and lessons learned from the Stardust comet sample return mission. We also highlight areas where sample collector and containment technology development and testing may be needed for future plume sample return missions.

  12. High Resolution Globe of Jupiter

    NASA Image and Video Library

    2001-01-30

    This true-color simulated view of Jupiter is composed of 4 images taken by NASA's Cassini spacecraft on December 7, 2000. To illustrate what Jupiter would have looked like if the cameras had a field-of-view large enough to capture the entire planet, the cylindrical map was projected onto a globe. The resolution is about 144 kilometers (89 miles) per pixel. Jupiter's moon Europa is casting the shadow on the planet. https://photojournal.jpl.nasa.gov/catalog/PIA02873

  13. A Day on Jupiter (Animation)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This 'movie' strings 11 images of Jupiter captured by the New Horizons Long Range Reconnaissance Imager (LORRI) on January 9, 2007, when the spacecraft was about 80 million kilometers (49.6 million miles) from the giant planet. The sequence covers a full 10-hour rotation of Jupiter, during which the moons Ganymede and Io -- as well as the shadows they cast on Jupiter -- move across the camera's field of view.

  14. Rubble around Jupiter

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    NASA's Jet Propulsion Laboratory has announced that Amalthea, a 270-km-long, potato-shaped inner moon of Jupiter, "apparently is a loosely packed pile of rubble," with empty space where the rubble does not fit well together.This is among the new findings about the moon announced by JPL astronomer John Anderson and his colleagues on 9 December at the AGU Fall Meeting in San Francisco.

  15. Relative astrobiological potential of irradiated icy bodies in the solar system

    NASA Astrophysics Data System (ADS)

    Cooper, John

    A common factor uniting icy moons with either putative subsurface oceans or evident cryo-volcanic activity is that these reside in the magnetospheres of the giant planets. Interestingly, the two known active moons, Enceladus and Triton, are not in the giant planet magnetosphere with the most extreme radiation, that of Jupiter. Either such radiation has little connection to activity, or else it might have an inhibiting effect at extreme levels such as at Europa. The astrobiological potential of Europa is generally thought to be the highest of the three Galilean icy moons, mainly since the putative global ocean would be closest to the surface, and yet there is little evidence for any significant abundance of organics at the surface. In contrast, ac-tive Enceladus clearly does have easily detectable abundances of simple hydrocarbons and may also have subsurface liquid water. The relatively shorter lifetimes with respect to radilolytic destruction might explain absence of surface organics on Europa, but the lack of gas-driven activity there also suggests absence of redox chemistry important to life as we know it. In the context of a model for gas produced by oxidation processes from radiolytic oxidants, Cooper et al. (Plan. Sp. Sci., 2009) earlier suggested that Europa, enveloped in a surface-bound oxygen atmosphere not detectably present at Enceladus, could be in an extreme state of oxidation to the limit that organics could not survive anywhere in the outer ice crust or underlying ocean. Could that mean that astrobiological potential is higher on Enceladus and even on Triton than on Europa? It is also noted that bright large Kuiper Belt Objects such as Eris may have icy surfaces continually replenished by cryovolcanism and hence might also have potentially significant astrobiological potential.

  16. The Jupiter System Observer: Exploring the Origins of Planetary Systems

    NASA Astrophysics Data System (ADS)

    Prockter, Louise; Senske, D.; Collins, G. C.; Cooper, J. F.; Hendrix, A.; Hibbitts, C.; Kivelson, M.; Schubert, G.; Showman, A.; Turtle, E.; Williams, D.

    2007-10-01

    The Jupiter System Observer (JSO) is one of four studies commissioned by NASA's Science Mission Directorate to examine the potential science return from a flagship-class mission to the outer solar system. JSO is a long-duration mission that will study the entire Jupiter system, focusing on both its individual components, including Jupiter's atmosphere, rocky and icy moons, rings, and magnetospheric phenomena, and the interactions between them. The wealth of data to be returned by JSO will enable a fuller understanding of a variety of magnetospheric, atmospheric, and geological processes, and will illuminate the question of how planetary systems form and evolve. The science team has outlined a number of significant science goals that can be accomplished by a spacecraft that tours the Jovian system for several years before ultimately ending up in Ganymede orbit. Ganymede was selected as the final destination for JSO because of its unique place in the Jovian system and the solar system - it is only the third body known to have its own dynamo-generated magnetic field. Ganymede is thought to contain a subsurface ocean and exhibits a surface with a variety of older and younger terrains, making it an excellent target for understanding the formation and evolution of icy satellites. Long-term monitoring of Jupiter's atmosphere and rings, Io's volcanism and torus, and high-resolution flyby imaging of Europa, Callisto and Io will enable an unprecedented study of the Jovian system as a solar system analog, and enables cross-cutting scientific objectives in the fields of atmospheres, geology, magnetospheres, and geophysics.

  17. Jupiter - First stop on Voyager's grand tour

    NASA Astrophysics Data System (ADS)

    Morrison, D.

    1989-08-01

    The findings concerning Jupiter that were made by the Voyager missions are briefly reviewed. The ring and three new moons around Jupiter, the live volcanoes on Io, and atmospheric phenomena on Jupiter which were observed by Voyager 1 are described. The discoveries regarding Callisto and Europa made by Voyager 2 are briefly summarized.

  18. Icy Satellites: Perpetual Permafrost

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Moore, J. M.

    2003-12-01

    The ice-rich moons of the outer solar system are worlds of perpetual permafrost. By analogy to the terrestrial roles of silicates and water ice, surface materials of these worlds commonly consist of components that are respectively refractory and volatile at local environmental conditions. We consider the physical properties, volatile components, and geomorphological characteristics of outer planet satellite surfaces and shallow regoliths as analogs to permafrost environments. Near-surface temperatures of ~40 to 165 K preclude melting of water-ice, except where endogenic activity has increased surface temperatures locally. However, water and/or more volatile ices can be transported in the vapor phase, and can liquefy in the deeper subsurface. In the water-ice-poor regolith of Io, SO2 and possibly H2S are volatile ices that can be transported in the vapor phase and can liquefy at depth, resulting in degradation and local collapse of the ground surface. Sublimation degradation is especially evident in images of Callisto, where slow diffusive loss of CO2 is the likely erosive agent. On Neptune's large moon Triton, nitrogen plays the role of a permafrost volatile, near its melting temperature in a regolith of more refractory ices. Most large icy satellites probably have water-rich subsurface oceans, and it has been proposed that Europa's subsurface ocean might sustain life. Frigid surface temperatures and severe charged particle radiation preclude near-surface metabolism, but organisms could potentially survive within deeper regions and local upwelling plumes that approach the ice melting temperature.

  19. Thickness Constraints on the Icy Shells of the Galilean Satellites from a Comparison of Crater Shapes

    NASA Technical Reports Server (NTRS)

    Schenk, Paul M.

    2002-01-01

    A thin outer ice shell on Jupiter's large moon Europa would imply easy exchange between the surface and any organic or biotic material in its putative subsurface ocean. The thickness of the outer ice shell is poorly constrained, however, with model-dependent estimates ranging from a few kilometers of depths of impact craters on Europa, Ganymede and Callisto that reveal two anomalous transitions in crater shape with diameter. The first transition is probably related to temperature-dependent ductility of the crust at shallow depths (7-8 km on Europa). The second transition is attributed to the influence of subsurface oceans on all three satellites, which constrains Europa's icy shell to be at least 19 km thick. The icy lithospheres of Ganymede and Callisto are equally ice-rich, but Europa's icy shell has a thermal structure about 0.25-0.5 times the thickness of Ganymede's or Callisto's shells, depending on epoch. The appearances of the craters on Europa are inconsistent with thin-ice-shell models and indicate that exchange of oceanic and surface material could be difficult.

  20. Thickness constraints on the icy shells of the galilean satellites from a comparison of crater shapes.

    PubMed

    Schenk, Paul M

    2002-05-23

    A thin outer ice shell on Jupiter's large moon Europa would imply easy exchange between the surface and any organic or biotic material in its putative subsurface ocean. The thickness of the outer ice shell is poorly constrained, however, with model-dependent estimates ranging from a few kilometres to ten or more kilometres. Here I present measurements of depths of impact craters on Europa, Ganymede and Callisto that reveal two anomalous transitions in crater shape with diameter. The first transition is probably related to temperature-dependent ductility of the crust at shallow depths (7 8 km on Europa). The second transition is attributed to the influence of subsurface oceans on all three satellites, which constrains Europa's icy shell to be at least 19 km thick. The icy lithospheres of Ganymede and Callisto are equally ice-rich, but Europa's icy shell has a thermal structure about 0.25 0.5 times the thicknesses of Ganymede's or Callisto's shells, depending on epoch. The appearances of the craters on Europa are inconsistent with thin-ice-shell models and indicate that exchange of oceanic and surface material could be difficult.

  1. Cost-Effective Icy Bodies Exploration using Small Satellite Missions

    NASA Technical Reports Server (NTRS)

    Jonsson, Jonas; Mauro, David; Stupl, Jan; Nayak, Michael; Aziz, Jonathan; Cohen, Aaron; Colaprete, Anthony; Dono-Perez, Andres; Frost, Chad; Klamm, Benjamin; hide

    2015-01-01

    It has long been known that Saturn's moon Enceladus is expelling water-rich plumes into space, providing passing spacecraft with a window into what is hidden underneath its frozen crust. Recent discoveries indicate that similar events could also occur on other bodies in the solar system, such as Jupiter's moon Europa and the dwarf planet Ceres in the asteroid belt. These plumes provide a possible giant leap forward in the search for organics and assessing habitability beyond Earth, stepping stones toward the long-term goal of finding extraterrestrial life. The United States Congress recently requested mission designs to Europa, to fit within a cost cap of $1B, much less than previous mission designs' estimates. Here, innovative cost-effective small spacecraft designs for the deep-space exploration of these icy worlds, using new and emerging enabling technologies, and how to explore the outer solar system on a budget below the cost horizon of a flagship mission, are investigated. Science requirements, instruments selection, rendezvous trajectories, and spacecraft designs are some topics detailed. The mission concepts revolve around a comparably small-sized and low-cost Plume Chaser spacecraft, instrumented to characterize the vapor constituents encountered on its trajectory. In the event that a plume is not encountered, an ejecta plume can be artificially created by a companion spacecraft, the Plume Maker, on the target body at a location timed with the passage of the Plume Chaser spacecraft. Especially in the case of Ceres, such a mission could be a great complimentary mission to Dawn, as well as a possible future Europa Clipper mission. The comparably small volume of the spacecraft enables a launch to GTO as a secondary payload, providing multiple launch opportunities per year. Plume Maker's design is nearly identical to the Plume Chaser, and fits within the constraints for a secondary payload launch. The cost-effectiveness of small spacecraft missions enables the

  2. Using Limb Profiles and Stereo Imagery for Ridge Comparisons on Icy Satellites

    NASA Astrophysics Data System (ADS)

    Patthoff, D. A.; Pappalardo, R. T.; Chilton, H.; Thomas, P. C.

    2013-12-01

    Many icy satellites of the outer solar system show signs of either ongoing or past tectonic activity. For this study, we explore the similarities and differences among tectonic ridges on different icy satellites and evaluate potential models of ridge formation. We focus on ridges that can be categorized as single or double ridges, ridge complexes, or ridged plains. Despite their prominence--ridges can be found on moons in each of the four outer planet systems--the nature of ridge formation remains incompletely understood and has been attributed to extensional, contractional, or strike-slip motions within icy lithospheres. Much of the previous work on ridges has focused on Jupiter's moon Europa, or relied on the older Voyager spacecraft data. Here we expand on previous studies to include new higher resolution images provided by the Galileo and Cassini orbiters, and we explore ridges on multiple icy satellites with a focus on Europa and Enceladus. We use a comparative planetological approach to evaluate the potential relationships among ridges in terms of the evolution of their structure, composition, morphology, and implied formation mechanisms. High-resolution limb images of the icy satellites are used to obtain cross-strike topographic profiles of ridges to determine symmetry, slope angle, and height. The profiles are used in conjunction with stereo imaging and shadow measurements to discern the shape of ridges and other proximal features. Additionally, we expand on geological mapping that has been performed for Europan ridges and apply similar techniques to ridges on Enceladus to evaluate the ridges' geological histories and compare the ridges on the different bodies. We seek to determine if there is a consistent sequence of ridge formation across several satellites, and if so, whether there is evidence for changes through time and with tidal stress history. Our measurements and characterization of multiple ridges on a variety of icy satellites will enable

  3. Magnetic Signature of Oceans in Icy Moons

    NASA Astrophysics Data System (ADS)

    Saur, Joachim

    2010-05-01

    Electromagnetic induction is a powerful technique to study the electrical conductivity of the interior of solar system bodies. Combined with other geophysical and cosmochemical information, the electrical conductivity structure can provide strong constraints on the associated internal composition of planetary bodies. Here we give a review of the basic principles of the electromagnetic induction technique and discuss its importance for the search for liquid water outside of Earth. Magnetic field measurements by the Galileo spacecraft provide strong evidence for a subsurface ocean on Europa and Callisto. The induction technique will provide additional important constraints on the possible subsurface water, when used on future Europa and Ganymede orbiters. It can also be applied to probe satellites such as Titan, Enceladus and Triton. We show that the plasma environment, in which the bodies are embedded, generates in addition to the induced magnetic fields competing plasma magnetic fields. These fields need to be treated appropriately to reliably interpret magnetic field measurements in the vicinity of solar system bodies.

  4. Jupiter Eye to Io

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image taken by NASA's Cassini spacecraft on Dec. 1, 2000, shows details of Jupiter's Great Red Spot and other features that were not visible in images taken earlier, when Cassini was farther from Jupiter.

    The picture is a color composite, with enhanced contrast, taken from a distance of 28.6 million kilometers (17.8 million miles). It has a resolution of 170 kilometers (106 miles) per pixel. Jupiter's closest large moon, Io, is visible at left.

    The edges of the Red Spot are cloudier with ammonia haze than the spot's center is. The filamentary structure in the center appears to spiral outward toward the edge. NASA's Galileo spacecraft has previously observed the outer edges of the Red Spot to be rotating rapidly counterclockwise, while the inner portion was rotating weakly in the opposite direction. Whether the same is true now will be answered as Cassini gets closer to Jupiter and interior cloud features become sharper. Cassini will make its closest approach to Jupiter, at a distance of about 10 million kilometers (6 million miles), on Dec. 30, 2000.

    The Red Spot region has changed in one notable way over the years: In images from NASA's Voyager and Galileo spacecraft, the area surrounding the Red Spot is dark, indicating relatively cloud-free conditions. Now, some bright white ammonia clouds have filled in the clearings. This appears to be part of a general brightening of Jupiter's cloud features during the past two decades.

    Jupiter has four large moons and an array of tiny ones. In this picture, Io is visible. The white and reddish colors on Io's surface are due to the presence of different sulfurous materials while the black areas are due to silicate rocks. Like the other large moons, Io always keeps the same hemisphere facing Jupiter, called the sub-Jupiter hemisphere. The opposite side, much of which we see here, is the anti-Jupiter hemisphere. Io has more than 100 active volcanoes spewing very hot lava and giant plumes of gas and dust. Its

  5. Potential Biospheres of the icy world in our solar systems

    NASA Astrophysics Data System (ADS)

    de Vera, Jean-Pierre Paul; Baqué, Mickael

    2016-04-01

    The challenge in astrobiology and planetary research in the near future is to realize space missions to study the habitability of Mars and the icy moons of the Jovian and Saturnian systems. Mars is an interesting object to search for habitable environments and for fossilized (and potentially present) life because of its past water driven wet history. On the other hand the Jovian moon Europa and the Saturnian moon Enceladus are promising candidates, where liquid water oceans beneath the surface are expected. These oceans can be habitable environments and the next challenge is to search there for present life. Some examples on potential biospheres and their biosignatures in Mars-like environments and in environmental conditions with reference to the icy moons will be given, which might exist in such kind of icy environments.

  6. A Secondary Ion Mass Analyzer for Remote Surface Composition Analysis of the Galilean Moons

    NASA Technical Reports Server (NTRS)

    Krueger, H.; Srama, R.; Johnson, T. V.; Henkel, H.; vonHoerner, H.; Koch, A.; Horanyi, M.; Gruen, E.; Kissel, J.; Krueger, F.

    2003-01-01

    Galileo in-situ dust measurements have shown that the Galilean moons are surrounded by tenuous dust clouds formed by collisional ejecta from their icy surfaces, kicked up by impacts of interplanetary micrometeoroids. The majority of the ejecta dust particles have been sensed at altitudes below five between 0.5 and 1 micron, just above the detector threshold, indicating a size distribution decreasing towards bigger particles. their parent bodies. They carry information about the properties of the surface from which they have been kicked up. In particular, these grains may carry organic compounds and other chemicals of biological relevance if they exist on the icy Galilean moons. In-situ analysis of the grain composition with a sophisticated dust analyzer instrument flying on a Jupiter Icy Moons Orbiter can provide important information about geochemical and geophysical processes during the evolutionary histories of these moons which are not accessible with other techniques from an orbiter spacecraft. Thus, spacecraft-based in-situ dust measurements can be used as a diagnostic tool for the analysis of the surface composition of the moons. This way, the in-situ measurements turn into a remote sensing technique by using the dust instrument like a telescope for surface investigation. An instrument capable of very high resolution composition analysis of dust particles is the Cometary Secondary Ion Mass Analyzer (COSIMA). The instrument was originally developed for the Comet Rendezvous and Asteroid Flyby (CRAF) mission and has now been built for ESA'S comet orbiter Rosetta. Dust particles are collected on a target and are later located by an optical microscope camera. A pulsed primary indium ion gun partially ionizes the dust grains. The generated secondary ions are accelerated in an electric field and travel through a reflectron-type time-of-flight ion mass spectrometer.

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

    NASA Technical Reports Server (NTRS)

    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. Building Small Icy Bodies: the Process of Icy Grain Aggregation

    NASA Astrophysics Data System (ADS)

    Fraser, Helen Jane; Hill, Catherine Rachel; Blum, Jurgen; Heisselmann, Daniel

    2015-08-01

    The material remaining in proto-planetary disks provides the ingredients from which planetessimals, and eventually comets, asteroids and planets (including their ring and moon systems) evolve. Aggregation processes are thought to proceed much more rapidly beyond snow-lines in such disks, aided by icy mantles on dust grains, but we do not know nano- and micron-scale dust combines to kilometer-sizes. Recent ALMA observations have proven the existence of snow lines in other proto-planetary systems (Qi et al Science (2013)), so it is by studying icy collisions in the laboratory that we can begin to understand the assembly of the icy bodies in our Solar System.Icy particles (between 4.7 and 10.8 mm in diameter) were collided at relative collision velocities of 0.27 - 0.51 m s-1, at 131 - 160 K, under microgravity conditions using a purpose-built experiment (Salter et al Rev Sci Inst (2010)). Bouncing was observed in the majority of collisions, across a full range of normalized impact parameters (b/R = 0.0-1.0). Coefficients of restitution were evenly spread between 0.08 and 0.65 with an average value of 0.36, leading to a minimum of 58% of translational energy being lost in the collision. The range of coefficients of restitution was attributed to the surface roughness of the particles. Analysis of particle rotation showed that up to 17% of the energy of the particles before the collision was converted into rotational energy. Temperature did not affect the coefficients of restitution over the range studied (Hill et all A&A (2015a)). The effects of chemical composition on the collisional outcomes were also studied, at relative particle impact velocities between 0.01 and 0.19 ms-1, temperatures between 131 and 160 K and a pressure of around 10-5 mbar. Overall the collisional properties of the icy particles were unchanged (Hill et al A&A (2015b)).The implications of these experimental results will be discussed in terms of our understanding of the formation and evolution of

  9. Jupiter small satellite montage

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo 'prime mission'--and was about to embark on a successful two-year extension, called the Galileo Europa Mission.

    The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views; this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter.

    The next two images show the moon Amalthea; they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that 'leads' as Amalthea moves in its orbit around Jupiter. This image looks 'noisy' because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent 'spots' of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis.

    In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles); Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles); Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles); Amalthea on November

  10. The sulphur dilemma: are there biosignatures on Europa's icy and patchy surface?

    NASA Astrophysics Data System (ADS)

    Chela-Flores, J.

    2006-07-01

    We discuss whether sulphur traces on Jupiter's moon Europa could be of biogenic origin. The compounds detected by the Galileo mission have been conjectured to be endogenic, most likely of cryovolcanic origin, due to their non-uniform distribution in patches. The Galileo space probe first detected the sulphur compounds, as well as revealing that this moon almost certainly has a volcanically heated and potentially habitable ocean hiding beneath a surface layer of ice. In planning future exploration of Europa there are options for sorting out the source of the surficial sulphur. For instance, one possibility is searching for the sulphur source in the context of the study of the Europa Microprobe In Situ Explorer (EMPIE), which has been framed within the Jovian Minisat Explorer Technology Reference Study (ESA). It is conceivable that sulphur may have come from the nearby moon Io, where sulphur and other volcanic elements are abundant. Secondly, volcanic eruptions in Europa's seafloor may have brought sulphur to the surface. Can waste products rising from bacterial colonies beneath the icy surface be a third alternative significant factor in the sulphur patches on the Europan surface? Provided that microorganisms on Europa have the same biochemical pathways as those on Earth, over geologic time it is possible that autochthonous microbes can add substantially to the sulphur deposits on the surface of Europa. We discuss possible interpretations of the non-water-ice elements (especially the sulphur compound mercaptan) in the context of the studies for future missions. To achieve reliable biosignatures it seems essential to go back to Europa. Our work highlights the type of biogenic signatures that can be searched for when probing Europa's icy and patchy surface.

  11. From Galileo's telescope to the Galileo spacecraft: our changing views of the Jupiter system

    NASA Astrophysics Data System (ADS)

    Lopes, R. M.

    2008-12-01

    In four centuries, we have gone from the discovery of the four large moons of Jupiter - Io, Europa, Ganymede, and Callisto - to important discoveries about these four very different worlds. Galileo's telescopic discovery was a major turning point in the understanding of science. His observations of the moons' motion around Jupiter challenged the notion of an Earth-centric Universe. A few months later, Galileo discovered the phases of Venus, which had been predicted by the heliocentric model of the Solar System. Galileo also observed the rings of Saturn (which he mistook for planets) and sunspots, and was the first person to report mountains and craters on the Moon, whose existence he deduced from the patterns of light and shadow on the Moon's surface, concluding that the surface was topographically rough. Centuries later, the Galileo spacecraft's discoveries challenged our understanding of outer planet satellites. Results included the discovery of an icy ocean underneath Europa's surface, the possibility of life on Europa, the widespread volcanism on Io, and the detection of a magnetic field around Ganymede. All four of these satellites revealed how the major geologic processes - volcanism, tectonism, impact cratering and erosion - operate in these different bodies, from the total lack of impact craters on Io to the heavily cratered, ancient surface of Callisto. The Galileo spacecraft's journey also took it to Venus and the Moon, making important scientific observations about these bodies. The spacecraft discovered the first moon orbiting around an asteroid which, had Galileo the man observed, would have been another major blow for the geocentric model of our Solar System.

  12. Europa Jupiter System Mission and Marco Polo Mission: Italian partecipation in studies of laser altimeters for Jovian moons and asteroids exploration.

    NASA Astrophysics Data System (ADS)

    Santovito, M. R.; Hussman, H.; Oberst, J.; Lingenauber, K.

    CO.RI.S.T.A. (Consortium for Research on Advanced Remote Sensing Systems) is member of international science teams devoted to the studies of laser altimeters to fly on Europa Jupiter System Mission (EJSM) and Marco Polo Mission, currently under study of ESA's Cosmic Vision program as L-class and M-class mission respectively. Both the studies will focus on the assessment of alternative technical approaches that would reduce the mass, size and power requirements. In particular a Single Photon Counting (SPC) device will be studied taking into account the robustness against false detections due to harsh radiation environment in the Jupiter system. Innovative technical aspects which will characterize the studies of laser altimeters in the scenarios of EJSM and MarcoPolo, which will permit us to make major contributions to the science goals of the two missions.

  13. OASIS: Organics Analyzer for Sampling Icy Surfaces

    NASA Technical Reports Server (NTRS)

    Getty, S. A.; Dworkin, J. P.; Glavin, D. P.; Martin, M.; Zheng, Y.; Balvin, M.; Southard, A. E.; Ferrance, J.; Malespin, C.

    2012-01-01

    Liquid chromatography mass spectrometry (LC-MS) is a well established laboratory technique for detecting and analyzing organic molecules. This approach has been especially fruitful in the analysis of nucleobases, amino acids, and establishing chirol ratios [1 -3]. We are developing OASIS, Organics Analyzer for Sampling Icy Surfaces, for future in situ landed missions to astrochemically important icy bodies, such as asteroids, comets, and icy moons. The OASIS design employs a microfabricated, on-chip analytical column to chromatographically separate liquid ana1ytes using known LC stationary phase chemistries. The elution products are then interfaced through electrospray ionization (ESI) and analyzed by a time-of-flight mass spectrometer (TOF-MS). A particular advantage of this design is its suitability for microgravity environments, such as for a primitive small body.

  14. Jupiter's Rings: Sharpest View

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  15. Sharpening Up Jupiter

    NASA Astrophysics Data System (ADS)

    2008-10-01

    New image-correction technique delivers sharpest whole-planet ground-based picture ever A record two-hour observation of Jupiter using a superior technique to remove atmospheric blur has produced the sharpest whole-planet picture ever taken from the ground. The series of 265 snapshots obtained with the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO's Very Large Telescope (VLT) reveal changes in Jupiter's smog-like haze, probably in response to a planet-wide upheaval more than a year ago. Sharpening Up Jupiter ESO PR Photo 33/08 Sharpening Up Jupiter Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques [1]. "This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae," says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. "While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations." MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble's 96-minute orbit. Using MAD, ESO astronomer Paola Amico

  16. Making Space Travel to Jupiter Possible

    NASA Technical Reports Server (NTRS)

    Barker, Samuel P.

    2004-01-01

    From man landing on the moon to a simple satellite being launched into orbit, many incredible space accomplishments have been witnessed by us all. However, what goes un-noticed to the common man is the extensive research and testing that lasts months, years, and even decades. Much of this required research just so happens to take place in the corridors of the Glen Research Center building number 49. In the Advanced Materials division of G.R.C., a number of researchers have the responsibility of discovering which metal, ceramic, or polymer is best for a specific application. Under the guidance of mentor extraordinaire Frank Ritzert, I am involved in many critical projects dealing with refractory metals, two of which I will mention in this report. The Jupiter Icy Moons Orbiter (JIMO) project actually was under full swing back in the 50's and early 60's. To enable the 14 year trek to the icy moons of Europa, Callisto, and Ganymede, nuclear propulsion methods were selected. Due to the extreme temperature of the reactor and the extended time period, a refractory metal would need to be implemented. After years of research and progress, the program was suddenly canceled. About a decade ago, the JIMO project was re-instated and now has a goal for departure around 2014. However, a few obstacles lie in our way concerning the use of refractory metals. In certain areas of the orbiter a joint is required between the refractories and other less dense metals. Two of these joints are with nickel based super alloys. Being an intern for Frank Ritzert, the refractory metals expert, I have the opportunity to develop the best method to braze refractory metals to Nickel 201. This involves the actual brazing, electron microscopy and reporting the results. My second project involves a certain part of the orbiter where Niobium 1Zirconium, a refractory metal, is joined with Hastelloy-X a Ni based metal. Small quantities of oxygen, helium and other impurities in the Ni alloy could diffuse

  17. Making Space Travel to Jupiter Possible

    NASA Technical Reports Server (NTRS)

    Barker, Samuel P.

    2004-01-01

    From man landing on the moon to a simple satellite being launched into orbit, many incredible space accomplishments have been witnessed by us all. However, what goes un-noticed to the common man is the extensive research and testing that lasts months, years, and even decades. Much of this required research just so happens to take place in the corridors of the Glen Research Center building number 49. In the Advanced Materials division of G.R.C., a number of researchers have the responsibility of discovering which metal, ceramic, or polymer is best for a specific application. Under the guidance of mentor extraordinaire Frank Ritzert, I am involved in many critical projects dealing with refractory metals, two of which I will mention in this report. The Jupiter Icy Moons Orbiter (JIMO) project actually was under full swing back in the 50's and early 60's. To enable the 14 year trek to the icy moons of Europa, Callisto, and Ganymede, nuclear propulsion methods were selected. Due to the extreme temperature of the reactor and the extended time period, a refractory metal would need to be implemented. After years of research and progress, the program was suddenly canceled. About a decade ago, the JIMO project was re-instated and now has a goal for departure around 2014. However, a few obstacles lie in our way concerning the use of refractory metals. In certain areas of the orbiter a joint is required between the refractories and other less dense metals. Two of these joints are with nickel based super alloys. Being an intern for Frank Ritzert, the refractory metals expert, I have the opportunity to develop the best method to braze refractory metals to Nickel 201. This involves the actual brazing, electron microscopy and reporting the results. My second project involves a certain part of the orbiter where Niobium 1Zirconium, a refractory metal, is joined with Hastelloy-X a Ni based metal. Small quantities of oxygen, helium and other impurities in the Ni alloy could diffuse

  18. Jupiter and the Voyager mission

    USGS Publications Warehouse

    Soderblom, L.; Spall, Henry

    1980-01-01

    In 1977, the United States launched two unmanned Voyager spacecraft that were to take part in an extensive reconnaissance of the outer planets over a 12-year period visiting the environs of Jupiter, Saturn, Uranus, and Neptune. Their first encounter was with the complex Jupiter planetary system 400 million miles away. Sweeping by Jupiter and its five moons in 1979, the two spacecraft have sent back to Earth an enormous amount of data that will prove to be vital in understanding our solar system. Voyager 1 is scheduled to fly past Saturn on November 13 of this year; Voyager 2, in August of the following year. 

  19. High-Pressure Hydrothermal Processing in Large Icy Satellites

    NASA Astrophysics Data System (ADS)

    Scott, H. P.; Hemley, R. J.; Ryerson, F. J.; Williams, Q.

    2002-12-01

    We have conducted a series of experiments designed to simulate chemical processes within large icy satellites. Few phase equilibria data exist which are relevant to the chemical evolution of moons such as Jupiter's Europa and Ganymede, Saturn's Titan and Neptune's Triton; however, models of their interiors are critically dependent on their internal chemistry and density. An internally generated magnetic field has been observed for Ganymede which implies the existence of a liquid metallic core, and accordingly an interior temperature exceeding 1000ṡC. This observation, coupled with the known abundance of water ice on Ganymede, suggests that rock - water interactions at high temperatures and pressures (prospectively in the past) would control the interior mineralogy of these satellites. Additionally, organic material has been observed on the surface of Ganymede, and in conjunction with the large complement of water ice, it has been suggested that icy satellites possess the prerequisites for life to originate; however, the stability of organic material under high-pressure hydrothermal processing is unclear. We used a piston-cylinder press to react material of carbonaceous chondrite chemistry with H2O at a range of temperatures and oxidation states at a pressure of 1.5 GPa, and make the following observations: 1) At temperatures below ~850ṡC the density of the rock interior will be largely that of hydrated ferromagnesian silicates (serpentine - chlorite - talc depending on temperature and oxidation state), 2) Iron and sulfur alloy readily under these conditions, forming the mineral pyrrhotite -- a metallic core of this chemistry is therefore likely, and 3) Hydrothermal processing of organic species of carbon at temperatures above 450ṡC produces carbonate minerals -- the prerequisite materials for life are not preserved deep within icy satellites. To further investigate the high-pressure hydrothermal processing of organic material we are conducting experiments

  20. Jupiter Eruptions

    NASA Image and Video Library

    2008-01-25

    NASA Hubble Space Telescope shows detailed analysis of two continent-sized storms that erupted in Jupiter atmosphere in March 2007 shows that Jupiter internal heat plays a significant role in generating atmospheric disturbances .

  1. Distant Moons

    NASA Image and Video Library

    2016-08-15

    Saturn's moons Tethys and Hyperion appear to be near neighbors in this Cassini view, even though they are actually 930,000 miles (1.5 million kilometers) apart here. Tethys is the larger body on the left. These two icy moons of Saturn are very different worlds. To learn more about Hyperion (170 miles or 270 kilometers across). This view looks toward the trailing side of Tethys. North on Tethys is up and rotated 1 degree to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 15, 2015. The view was acquired at a distance of approximately 750,000 miles (1.2 million kilometers) from Tethys. Image scale is 4.4 miles (7.0 kilometers) per pixel. The distance to Hyperion was 1.7 million miles (2.7 million kilometers) with an image scale of 10 mile (16 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20493

  2. Storms and Moons

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this 2-millisecond exposure of Jupiter at 04:41:04 UTC on January 24, 2007. The spacecraft was 57 million kilometers (35.3 million miles) from Jupiter, closing in on the giant planet at 41,500 miles (66,790 kilometers) per hour. At right are the moons Io (bottom) and Ganymede; Ganymede's shadow creeps toward the top of Jupiter's northern hemisphere.

    Two of Jupiter's largest storms are visible; the Great Red Spot on the western (left) limb of the planet, trailing the Little Red Spot on the eastern limb, at slightly lower latitude. The Great Red Spot is a 300-year old storm more than twice the size of Earth. The Little Red Spot, which formed over the past decade from the merging of three smaller storms, is about half the size of its older and 'greater' counterpart.

  3. A permanent, asymmetric dust cloud around the Moon

    NASA Astrophysics Data System (ADS)

    Horányi, M.; Szalay, J. R.; Kempf, S.; Schmidt, J.; Grün, E.; Srama, R.; Sternovsky, Z.

    2015-06-01

    Interplanetary dust particles hit the surfaces of airless bodies in the Solar System, generating charged and neutral gas clouds, as well as secondary ejecta dust particles. Gravitationally bound ejecta clouds that form dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, but have hitherto not been observed near bodies with refractory regolith surfaces. High-altitude Apollo 15 and 17 observations of a `horizon glow' indicated a putative population of high-density small dust particles near the lunar terminators, although later orbital observations yielded upper limits on the abundance of such particles that were a factor of about 104 lower than that necessary to produce the Apollo results. Here we report observations of a permanent, asymmetric dust cloud around the Moon, caused by impacts of high-speed cometary dust particles on eccentric orbits, as opposed to particles of asteroidal origin following near-circular paths striking the Moon at lower speeds. The density of the lunar ejecta cloud increases during the annual meteor showers, especially the Geminids, because the lunar surface is exposed to the same stream of interplanetary dust particles. We expect all airless planetary objects to be immersed in similar tenuous clouds of dust.

  4. A permanent, asymmetric dust cloud around the Moon.

    PubMed

    Horányi, M; Szalay, J R; Kempf, S; Schmidt, J; Grün, E; Srama, R; Sternovsky, Z

    2015-06-18

    Interplanetary dust particles hit the surfaces of airless bodies in the Solar System, generating charged and neutral gas clouds, as well as secondary ejecta dust particles. Gravitationally bound ejecta clouds that form dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, but have hitherto not been observed near bodies with refractory regolith surfaces. High-altitude Apollo 15 and 17 observations of a 'horizon glow' indicated a putative population of high-density small dust particles near the lunar terminators, although later orbital observations yielded upper limits on the abundance of such particles that were a factor of about 10(4) lower than that necessary to produce the Apollo results. Here we report observations of a permanent, asymmetric dust cloud around the Moon, caused by impacts of high-speed cometary dust particles on eccentric orbits, as opposed to particles of asteroidal origin following near-circular paths striking the Moon at lower speeds. The density of the lunar ejecta cloud increases during the annual meteor showers, especially the Geminids, because the lunar surface is exposed to the same stream of interplanetary dust particles. We expect all airless planetary objects to be immersed in similar tenuous clouds of dust.

  5. Thermal Conductivity Measurements on Icy Satellite Analogs

    NASA Technical Reports Server (NTRS)

    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.

  6. Thermal Conductivity Measurements on Icy Satellite Analogs

    NASA Technical Reports Server (NTRS)

    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.

  7. Physical Conditions and Exobiology Potential of Icy Satellites of the Giant Planets

    NASA Astrophysics Data System (ADS)

    Simakov, M. B.

    2017-05-01

    All giant planets of the Solar system have a big number of satellites. A small part of them consist very large bodies, quite comparable to planets of terrestrial type, but including very significant share of water ice. Galileo spacecraft has given indications, primarily from magnetometer and gravity data, of the possibility that three of Jupiter's four large moons, Europa, Ganymede and Callisto have internal oceans. Formation of such satellites is a natural phenomenon, and satellite systems definitely should exist at extrasolar planets. The most recent models of the icy satellites interior lead to the conclusion that a substantial liquid layer exists today under relatively thin ice cover inside. The putative internal water ocean provide some exobiological niches on these bodies. We can see all conditions needed for origin and evolution of biosphere - liquid water, complex organic chemistry and energy sources for support of biological processes - are on the moons. The existing of liquid water ocean within icy world can be consequences of the physical properties of water ice, and they neither require the addition of antifreeze substances nor any other special conditions. On Earth life exists in all niches where water exists in liquid form for at least a portion of the year. Possible metabolic processes, such as nitrate/nitrite reduction, sulfate reduction and methanogenesis could be suggested for internal oceans of Titan and Jovanian satellites. Excreted products of the primary chemoautotrophic organisms could serve as a source for other types of microorganisms (heterotrophes). Subglacial life may be widespread among such planetary bodies as satellites of extrasolar giant planets, detected in our Galaxy.

  8. PCS-ICIS Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  9. Virtual observatory tools and amateur radio observations supporting scientific analysis of Jupiter radio emissions

    NASA Astrophysics Data System (ADS)

    Cecconi, Baptiste; Hess, Sebastien; Le Sidaner, Pierre; Savalle, Renaud; Stéphane, Erard; Coffre, Andrée; Thétas, Emmanuel; André, Nicolas; Génot, Vincent; Thieman, Jim; Typinski, Dave; Sky, Jim; Higgins, Chuck; Imai, Masafumi

    2016-04-01

    In the frame of the preparation of the NASA/JUNO and ESA/JUICE (Jupiter Icy Moon Explorer) missions, and the development of a planetary sciences virtual observatory (VO), we are proposing a new set of tools directed to data providers as well as users, in order to ease data sharing and discovery. We will focus on ground based planetary radio observations (thus mainly Jupiter radio emissions), trying for instance to enhance the temporal coverage of jovian decametric emission. The data service we will be using is EPN-TAP, a planetary science data access protocol developed by Europlanet-VESPA (Virtual European Solar and Planetary Access). This protocol is derived from IVOA (International Virtual Observatory Alliance) standards. The Jupiter Routine Observations from the Nancay Decameter Array are already shared on the planetary science VO using this protocol, as well as data from the Iitate Low Frquency Radio Antenna, in Japan. Amateur radio data from the RadioJOVE project is also available. The attached figure shows data from those three providers. We will first introduce the VO tools and concepts of interest for the planetary radioastronomy community. We will then present the various data formats now used for such data services, as well as their associated metadata. We will finally show various prototypical tools that make use of this shared datasets.

  10. The Saturnian moon Enceladus

    NASA Technical Reports Server (NTRS)

    1982-01-01

    This high-resolution image of Enceladus was made from several images obtained Aug. 25, 1981, by Voyager 2 from a range of 119,000 kilometers (74,000 miles). It shows further surface detail on this Saturnian moon. Enceladus is seen to resemble Jupiter's moon Ganymede, which is, however, about 10 times larger. Faintly visible here in light reflected from Saturn is the hemisphere turned away from the sun. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Morphology and Scaling of Ejecta Deposits on Icy Satellites

    NASA Technical Reports Server (NTRS)

    Schenk, Paul M.; Ridolfi, Francis J.; Bredekamp, Joe (Technical Monitor)

    2002-01-01

    Continuous ejecta deposits on Ganymede consist of two major units, or facies: a thick inner hummocky pedestal facies, and a relatively thin outer radially scoured facies defined also by the inner limit of the secondary crater field. Both ejecta facies have a well-defined power-law relationship to crater diameter for craters ranging from 15 to approx. 600 km across. This relationship can be used to estimate the nominal crater diameter for impact features on icy satellites (such as palimpsests and multiring basins) for which the crater rim is no longer recognizable. Ejecta deposits have also been mapped on 4 other icy satellites. Although morphologically similar to eject deposits on the Moon, ejecta deposits for smaller craters are generally significantly broader in extent on the icy satellites, in apparent defiance of predictions of self-similarity. A greater degree of rim collapse and enlargement on the Moon may explain the observed difference.

  13. Galileo's Telescopy and Jupiter's Tablet

    NASA Astrophysics Data System (ADS)

    Usher, P. D.

    2003-12-01

    A previous paper (BAAS 33:4, 1363, 2001) reported on the dramatic scene in Shakespeare's Cymbeline that features the descent of the deity Jupiter. The paper suggested that the four ghosts circling the sleeping Posthumus denote the four Galilean moons of Jupiter. The god Jupiter commands the ghosts to lay a tablet upon the prone Posthumus, but says that its value should not be overestimated. When Posthumus wakens he notices the tablet, which he calls a "book." Not only has the deity's "tablet" become the earthling's "book," but it appears that the book has covers which Posthumus evidently recognizes because without even opening the book he ascribes two further properties to it: rarity, and the very property that Jupiter had earlier attributed, viz. that one must not read too much into it. The mystery deepens when the Jovian gift undergoes a second metamorphosis, to "label." With the help of the OED, the potentially disparate terms "tablet," "book," and "label," may be explained by terms appropriate either to supernatural or worldly beings. "Tablet" may recognize the Mosaic artifact, whereas "book" and "label" are probably mundane references to Galileo's Sidereus Nuncius which appeared shortly before Cymbeline. The message of the Olympian god indicates therefore that the book is unique even as its contents have limited value. The first property celebrates the fact that Galileo's book is the first of its kind, and the second advises that all results except the discovery of Jupiter's moons have been reported earlier, in Hamlet.

  14. The Icy Mountains of Pluto

    NASA Image and Video Library

    2015-07-15

    New close-up images of a region near Pluto's equator reveal a giant surprise: a range of youthful mountains rising as high as 11,000 feet (3,500 meters) above the surface of the icy body. The mountains likely formed no more than 100 million years ago -- mere youngsters relative to the 4.56-billion-year age of the solar system -- and may still be in the process of building. That suggests the close-up region, which covers less than one percent of Pluto's surface, may still be geologically active today. The youthful age estimate is based on the lack of craters in this scene. Like the rest of Pluto, this region would presumably have been pummeled by space debris for billions of years and would have once been heavily cratered -- unless recent activity had given the region a facelift, erasing those pockmarks. Unlike the icy moons of giant planets, Pluto cannot be heated by gravitational interactions with a much larger planetary body. Some other process must be generating the mountainous landscape. The mountains are probably composed of Pluto's water-ice "bedrock." Although methane and nitrogen ice covers much of the surface of Pluto, these materials are not strong enough to build the mountains. Instead, a stiffer material, most likely water-ice, created the peaks. The close-up image was taken about 1.5 hours before New Horizons closest approach to Pluto, when the craft was 47,800 miles (770,000 kilometers) from the surface of the planet. The image easily resolves structures smaller than a mile across. http://photojournal.jpl.nasa.gov/catalog/PIA19710

  15. Jupiter Eruptions

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  16. Jupiter Eruptions

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  17. Spatial distribution of water in the stratosphere of Jupiter from observations with the Herschel space observatory

    NASA Astrophysics Data System (ADS)

    Cavalié, T.; Feuchtgruber, H.; Lellouch, E.; de Val-Borro, M.; Jarchow, C.; Moreno, R.; Hartogh, P.; Orton, G.; Greathouse, T. K.; Billebaud, F.; Dobrijevic, M.; Lara, L. M.; Gonzalez, A.; Sagawa, H.

    2013-09-01

    distributions of water in Jupiter's stratosphere, we rule out interplanetary dust particles as its main source. Furthermore, we demonstrate that Jupiter's stratospheric water was delivered by the SL9 comet and that more than 95% of the observed water comes from the comet according to our models. On the longer term, this study can be regarded as a preparation of the observations to be performed by the SubmillimetreWave Instrument (SWI) [12]. SWI is an instrument proposed for the payload of the Jupiter Icy Moon Explorer (JUICE). This instrument will observe water and the other SL9-derived species in Jupiter with a higher spatiotemporal resolution than Herschel to constrain its 3D stratospheric circulation.

  18. Jupiter Wave

    NASA Image and Video Library

    2015-10-13

    Scientists spotted a rare wave in Jupiter North Equatorial Belt that had been seen there only once before in this false-color close-up from NASA Hubble Telescope. In Jupiter's North Equatorial Belt, scientists spotted a rare wave that had been seen there only once before. It is similar to a wave that sometimes occurs in Earth's atmosphere when cyclones are forming. This false-color close-up of Jupiter shows cyclones (arrows) and the wave (vertical lines). http://photojournal.jpl.nasa.gov/catalog/PIA19659

  19. Dust Mass Spectrometer for Compositional Mapping of the Galilean Moons

    NASA Astrophysics Data System (ADS)

    Sternovsky, Zoltan; Kempf, S.; Briois, C.; Cottin, H.; Engrand, C.; Horanyi, M.; Gruen, E.; Hand, K.; Henkel, H.; Lebreton, J.; Postbert, F.; Schmidt, J.; Srama, R.; Thissen, R.; Tobie, G.; Szopa, C.; Zolotov, M.

    2012-10-01

    We present the SUDA (Surface Dust Analyzer) instrument that will provide detailed answers to the main goals of ESA's JUICE mission about habitability, surface composition and exchange processes with the interior. The surfaces of the icy moons of Jupiter can be analyzed to unprecedented mass resolution and sensitivity down to the ppm level using modern dust analyzer instruments. The measurement method is based on analyzing the chemical composition of dust particles released from the surfaces of the moons. These dust particles populate the exosphere with densities sufficient for obtaining a valuable compositional picture even from a few flybys. The SUDA instrument is well suited for the detection of water ice particles with traces of the expected hydrated minerals such as sodium carbonates and magnesium sulphates, hydrated sodium chloride, and of organic materials. The value of a dust analyzer is well demonstrated by Cassini's Cosmic Dust Analyzer that has analyzed Enceladus's plume particles and E ring grains. SUDA is a time-of-flight, reflectron-type impact mass spectrometer, optimized for high mass resolution. The small size (268×250×171 mm3), low mass (< 4 kg) and large sensitive area (220 cm2) makes the instrument well suited for the challenging demands of the JUICE mission. A full-size prototype was used to demonstrate the performance through calibration experiments with a variety of cosmochemically relevant dust analogues. The effective mass resolution of m/Δm of 150- 200 is achieved for mass range of interest m = 1-150.

  20. Galileo Earth Moon Flyby

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This video has five sections. The first is a live discussion of the information that scientists hope to gain by the Galileo flyby of the Moon. This section has no introduction. There is a great deal of the discussion about the lunar craters and lunar volcanism. There is also some discussion of the composition of the far side of the moon. The second section is a short animation that shows the final step to Jupiter with particular emphasis on the gravitational assisted velocity boost, which was planned to give the spacecraft the requisite velocity to make the trip to Jupiter. The next section is an update of the status of the flyby of the Moon, and the Earth, with an explanation of the trajectory around the earth, and the moon. A photograph of the tracking station in Canberra, Australia is included. The next section is a tour of a full-scale model of the spacecraft. The last section is a discussion with the person charged with the procurement of the instrumentation aboard the spacecraft; the importance of the lunar flyby to assist in the calibration of the instruments is discussed.

  1. Galileo Earth Moon Flyby

    NASA Astrophysics Data System (ADS)

    1992-12-01

    This video has five sections. The first is a live discussion of the information that scientists hope to gain by the Galileo flyby of the Moon. This section has no introduction. There is a great deal of the discussion about the lunar craters and lunar volcanism. There is also some discussion of the composition of the far side of the moon. The second section is a short animation that shows the final step to Jupiter with particular emphasis on the gravitational assisted velocity boost, which was planned to give the spacecraft the requisite velocity to make the trip to Jupiter. The next section is an update of the status of the flyby of the Moon, and the Earth, with an explanation of the trajectory around the earth, and the moon. A photograph of the tracking station in Canberra, Australia is included. The next section is a tour of a full-scale model of the spacecraft. The last section is a discussion with the person charged with the procurement of the instrumentation aboard the spacecraft; the importance of the lunar flyby to assist in the calibration of the instruments is discussed.

  2. Jupiter Temperatures

    NASA Image and Video Library

    1997-09-29

    This is one of the highest resolution images ever recorded of Jupiter temperature field. It was obtained by NASA Galileo mission. This map, shown in the lower panel, indicates the forces powering Jovian winds.

  3. Jupiter's Magnetotail

    NASA Astrophysics Data System (ADS)

    Krupp, Norbert; Kronberg, Elena; Radioti, Aikaterini

    2015-01-01

    The spacecraft exploration of Jupiter and its environment has a history of approximately 40 years. Jupiter's magnetotail is highly dynamic and changes in the overall particles and field parameters occur on time scales of minutes up to several days. Jupiter is rotationally driven and the solar wind does not play the major role as at Earth. This chapter summarizes the current knowledge about particle and field observations from Jupiter's outer magnetodisc and magnetotail. The observed "energetic events" measured in energetic particles, plasma and radio waves, magnetic field north-south component, and auroral emissions occur throughout the magnetotail. They are most likely related to reconnection in the tail and appear quasi-periodically every few days, especially in the predawn sector of the magnetosphere.

  4. Ulysses dust measurements near Jupiter.

    PubMed

    Grün, E; Zook, H A; Baguhl, M; Fechtig, H; Hanner, M S; Kissel, J; Lindblad, B A; Linkert, D; Linkert, G; Mann, I B

    1992-09-11

    Submicrometer- to micrometer-sized particles were recorded by the Ulysses dust detector within 40 days of the Jupiter flyby. Nine impacts were recorded within 50 Jupiter radii with most of them recorded after closest approach. Three of these impacts are consistent with particles on prograde orbits around Jupiter and the rest are believed to have resulted from gravitationally focused interplanetary dust. From the ratio of the impact rate before the Jupiter flyby to the impact rate after the Jupiter flyby it is concluded that interplanetary dust particles at the distance of Jupiter move on mostly retrograde orbits. On 10 March 1992, Ulysses passed through an intense dust stream. The dust detector recorded 126 impacts within 26 hours. The stream particles were moving on highly inclined and apparently hyperbolic orbits with perihelion distances of >5 astronomical units. Interplanetary dust is lost rather quickly from the solar system through collisions and other mechanisms and must be almost continuously replenished to maintain observed abundances. Dust flux measurements, therefore, give evidence of the recent rates of production from sources such as comets, asteroids, and moons, as well as the possible presence of interstellar grains.

  5. Ulysses dust measurements near Jupiter

    NASA Technical Reports Server (NTRS)

    Gruen, Eberhard; Zook, Herbert A.; Baguhl, Michael; Fechtig, Hugo; Hanner, Martha S.; Kissel, Jochen; Lindblad, Bertil A.; Linkert, Dietmar; Linkert, Gudrun; Mann, Ingrid B.

    1992-01-01

    Submicrometer- to micrometer-sized particles were recorded by the Ulysses dust detector within 40 days of the Jupiter flyby. Nine impacts were recorded within 50 Jupiter radii with most of them recorded after closest approach. Three of these impacts are consistent with particles on prograde orbits around Jupiter and the rest are believed to have resulted from gravitationally focused interplanetary dust. From the ratio of the impact rate before the Jupiter flyby to the impact rate after the Jupiter flyby it is concluded that interplanetary dust particles at the distance of Jupiter move on mostly retrograde orbits. On 10 March 1992, Ulysses passed through an intense dust stream. The dust detector recorded 126 impacts within 26 hours. The stream particles were moving on highly inclined and apparently hyperbolic orbits with perihelion distances of greater than 5 astronomical units. Interplanetary dust is lost rather quickly from the solar system through collisions and other mechanisms and must be almost continuously replenished to maintain observed abundances. Dust flux measurements, therefore, give evidence of the recent rates of production from sources such as comets, asteroids, and moons, as well as the possible presence of interstellar grains.

  6. Icy Particle Spray

    NASA Image and Video Library

    2010-11-18

    Images obtained by NASA EPOXI mission spacecraft show an active end of the nucleus of comet Hartley 2. Icy particles spew from the surface. Most of these particles are traveling with the nucleus; fluffy nowballs about 3 centimeters to 30 centimeters.

  7. Moon Jumble

    NASA Image and Video Library

    2009-12-23

    A gaggle of moons parade around Saturn rings in this image from NASA Cassini spacecraft in which the large moon Rhea passes in front of the small moon Janus. Go to the Photojournal to view the animation.

  8. Europa, taken from Voyager 1 to Jupiter

    NASA Image and Video Library

    1979-03-01

    Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd Galilean satellites from the planet and the brightest. Photo taken early morning through violet filter. Faint swirls and linear patterns show in the equatorial region (which shows darker than the poles). This hemisphere always faces Jupiter. North is up. Density and size comparable to Earth's Moon and seems to show water ice or ground water on its surface. JPL Reference # P-21163.

  9. Io's volcanism influences Jupiter's magnetosphere

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-02-01

    Volcanic emissions from Jupiter's moon Io supply plasma to the planet's magnetosphere and lead to its main auroral emissions. New observations show that the main auroral oval expanded and outer emissions brightened in spring 2007. Some studies have suggested that magnetospheric changes such as these could be caused by changes in the incoming solar wind. Bonfond et al. present several lines of evidence—including images from the Hubble Space Telescope and observations of a volcanic plume on Io from the New Horizons probe along with measurements of increased emissions from Jupiter's sodium cloud—that indicate that Io's volcanism controls changes in Jupiter's magnetosphere. (Geophysical Research Letters, doi:10.1029/2011GL050253, 2012)

  10. High Resolution Globe of Jupiter

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This true-color simulated view of Jupiter is composed of 4 images taken by NASA's Cassini spacecraft on December 7, 2000. To illustrate what Jupiter would have looked like if the cameras had a field-of-view large enough to capture the entire planet, the cylindrical map was projected onto a globe. The resolution is about 144 kilometers (89 miles) per pixel. Jupiter's moon Europa is casting the shadow on the planet.

    Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.

  11. High Resolution Globe of Jupiter

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This true-color simulated view of Jupiter is composed of 4 images taken by NASA's Cassini spacecraft on December 7, 2000. To illustrate what Jupiter would have looked like if the cameras had a field-of-view large enough to capture the entire planet, the cylindrical map was projected onto a globe. The resolution is about 144 kilometers (89 miles) per pixel. Jupiter's moon Europa is casting the shadow on the planet.

    Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.

  12. Ultraviolet Photometric Parameters of the Icy Galilean Satellites

    NASA Technical Reports Server (NTRS)

    Hendrix, Amanda R.; Domingue, Deborah L.; King, Kimberly

    2002-01-01

    The Galilean satellites are each phase-locked with Jupiter, so that one hemisphere (the Jovian hemisphere centered on 0 deg longitude) is always facing Jupiter. The leading hemisphere is centered on 90 deg W longitude, while the central longitude of the trailing hemisphere is 270 deg W. Because Jupiter's magnetosphere corotates at a rate faster than the orbital speed of the moons, the satellites' trailing hemispheres are affected by magnetospheric particle bombardment. Some effects are implantation of magnetospheric ions, sputtering, erosion and grain size alteration. The leading hemispheres of these moons are more dominantly affected by micrometeorite bombardment, while the Jovian hemispheres may be affected by dust and/or neutral wind particles streaming out radially from Io and its torus.

  13. Alice Views Jupiter and Io

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This graphic illustrates the pointing and shows the data from one of many observations made by the New Horizons Alice ultraviolet spectrometer (UVS) instrument during the Pluto-bound spacecraft's recent encounter with Jupiter. The red lines in the graphic show the scale, orientation, and position of the combined 'box and slot' field of view of the Alice UVS during this observation.

    The positions of Jupiter's volcanic moon, Io, the torus of ionized gas from Io, and Jupiter are shown relative to the Alice field of view. Like a prism, the spectrometer separates light from these targets into its constituent wavelengths.

    Io's volcanoes produce an extremely tenuous atmosphere made up primarily of sulfur dioxide gas, which, in the harsh plasma environment at Io, breaks down into its component sulfur and oxygen atoms. Alice observed the auroral glow from these atoms in Io's atmosphere and their ionized counterparts in the Io torus.

    Io's dayside is deliberately overexposed to bring out faint details in the plumes and on the moon's night side. The continuing eruption of the volcano Tvashtar, at the 1 o'clock position, produces an enormous plume roughly 330 kilometers (200 miles) high, which is illuminated both by sunlight and 'Jupiter light.'

  14. The EJSM Jupiter-Europa Orbiter: Science Objectives

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Blanc, M.; Clark, K.; Greeley, R.; Hendrix, A. R.; Lebreton, J.-P.

    2008-09-01

    Europa is believed to shelter an ocean between its geodynamically active icy shell and its rocky mantle, where the conditions for habitability may be fulfilled. With a warm, salty, water ocean and plausible chemical energy sources, Europa is the astrobiological archetype for icy satellite habitability. It is also a geophysical wonderland of interrelated ice shell processes that are intimately related to the ocean and tides, and of complex interactions among its interior, surface, atmosphere, and magnetospheric environments. The Jupiter-Europa Orbiter (JEO) is one component of the proposed multi-spacecraft Europa Jupiter System Mission (EJSM). We focus here on the science objectives and heritage of JEO.

  15. Jupiter-Io Montage

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This is a montage of New Horizons images of Jupiter and its volcanic moon Io, taken during the spacecraft's Jupiter flyby in early 2007. The Jupiter image is an infrared color composite taken by the spacecraft's near-infrared imaging spectrometer, the Linear Etalon Imaging Spectral Array (LEISA) at 1:40 UT on Feb. 28, 2007. The infrared wavelengths used (red: 1.59 um, green: 1.94 um, blue: 1.85 um) highlight variations in the altitude of the Jovian cloud tops, with blue denoting high-altitude clouds and hazes, and red indicating deeper clouds. The prominent bluish-white oval is the Great Red Spot. The observation was made at a solar phase angle of 75 degrees but has been projected onto a crescent to remove distortion caused by Jupiter's rotation during the scan. The Io image, taken at 00:25 UT on March 1st 2007, is an approximately true-color composite taken by the panchromatic Long-Range Reconnaissance Imager (LORRI), with color information provided by the 0.5 um ('blue') and 0.9 um ('methane') channels of the Multispectral Visible Imaging Camera (MVIC). The image shows a major eruption in progress on Io's night side, at the northern volcano Tvashtar. Incandescent lava glows red beneath a 330-kilometer high volcanic plume, whose uppermost portions are illuminated by sunlight. The plume appears blue due to scattering of light by small particles in the plume

    This montage appears on the cover of the Oct. 12, 2007, issue of Science magazine.

  16. Jupiter-Io Montage

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This is a montage of New Horizons images of Jupiter and its volcanic moon Io, taken during the spacecraft's Jupiter flyby in early 2007. The Jupiter image is an infrared color composite taken by the spacecraft's near-infrared imaging spectrometer, the Linear Etalon Imaging Spectral Array (LEISA) at 1:40 UT on Feb. 28, 2007. The infrared wavelengths used (red: 1.59 um, green: 1.94 um, blue: 1.85 um) highlight variations in the altitude of the Jovian cloud tops, with blue denoting high-altitude clouds and hazes, and red indicating deeper clouds. The prominent bluish-white oval is the Great Red Spot. The observation was made at a solar phase angle of 75 degrees but has been projected onto a crescent to remove distortion caused by Jupiter's rotation during the scan. The Io image, taken at 00:25 UT on March 1st 2007, is an approximately true-color composite taken by the panchromatic Long-Range Reconnaissance Imager (LORRI), with color information provided by the 0.5 um ('blue') and 0.9 um ('methane') channels of the Multispectral Visible Imaging Camera (MVIC). The image shows a major eruption in progress on Io's night side, at the northern volcano Tvashtar. Incandescent lava glows red beneath a 330-kilometer high volcanic plume, whose uppermost portions are illuminated by sunlight. The plume appears blue due to scattering of light by small particles in the plume

    This montage appears on the cover of the Oct. 12, 2007, issue of Science magazine.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Hubble Images Reveal Jupiter's Auroras

    NASA Technical Reports Server (NTRS)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.

    The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.

    The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.

    The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.

    The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.

    This image and

  20. Moon Phases

    ERIC Educational Resources Information Center

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  1. Moon Phases

    ERIC Educational Resources Information Center

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  2. Compositions of Oceans on Icy Solar System Bodies (Invited)

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2010-12-01

    Interior oceans may exist on at least several solar system bodies: Europa, Enceladus, Ganymede, Titan and Triton. Compositions of the oceans could reflect bulk chemistries on the bodies, degree and timing of differendentition, current temperature and pressure conditions, and chemical exchanges between icy shells, liquid layers, and suboceanic solids (rocks, sediments, ices and clathrates). Observational signs are sparse and modeling is the major approach to evaluate oceanic compositions. On Europa, a presence of S(VI) species and CO2 at endogenic surface features [1] suggests sulfates and C species (organic and/or inorganic) in the ocean. The detection of NaCl and Na2CO3/NaHCO3-bearing grains emitted from Enceladus [2] implies the dominance of Na, Cl and carbonate/bicarbonate ions in the past and/or present alkaline fluids in the interior. These observations are consistent with independent models for water-rock interaction [3]. Evaluated low contents of other elements (Mg, Fe, Ca, K, S, P, etc.) in initial oceanic waters [3] are accounted for by low solubilities of minerals deposited from water solutions (serpentine, saponite, magnetite, carbonates, sulfides and phosphates). Oceanic redox states are affected by the composition of accreted ices and rocks, hydrogen production through oxidation of solids (mainly Fe-Ni metal) by water and an efficiency of H2 escape. Formation of a sulfate-bearing ocean (as on Europa) through oxidation of sulfides could have been driven by radiolytically-formed oxidants (H2O2, O2), high-temperature (>500 K) hydrothermal activity and H2 escape. Formation of sulfate facilitates leaching of Mg from minerals leading to the Mg-SO4-Na-Cl ocean. Although some of these factors could have played roles on the Galilean satellites, formation of sulfate-bearing oceans beyond Jupiter is unlikely. Accretion of cometary-type ices on moons allows an existence of water-methanol-ammonia liquids at ~153 K, although ammonia could have been sequestered in

  3. Approaching Jupiter

    NASA Image and Video Library

    2017-05-05

    This enhanced color view of Jupiter's south pole was created by citizen scientist Gabriel Fiset using data from the JunoCam instrument on NASA's Juno spacecraft. Oval storms dot the cloudscape. Approaching the pole, the organized turbulence of Jupiter's belts and zones transitions into clusters of unorganized filamentary structures, streams of air that resemble giant tangled strings. The image was taken on Dec. 11, 2016 at 9:44 a.m. PST (12:44 p.m. EST), from an altitude of about 32,400 miles (52,200 kilometers) above the planet's beautiful cloud tops. https://photojournal.jpl.nasa.gov/catalog/PIA21390

  4. Overview of the Project Prometheus Program

    NASA Technical Reports Server (NTRS)

    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.

  5. Overview of the Project Prometheus Program

    NASA Technical Reports Server (NTRS)

    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.

  6. Mass-radius relationships in icy satellites

    NASA Technical Reports Server (NTRS)

    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.

  7. On Approach: Jupiter and Io

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of On Approach: Jupiter and Io

    This sequence of images was taken on Jan. 8, 2007, with the New Horizons Long Range Reconnaissance Imager (LORRI), while the spacecraft was about 81 million kilometers (about 50 million miles) from Jupiter. Jupiter's volcanic moon Io is to the right; the planet's Great Red Spot is also visible. The image was one of 11 taken during the Jan. 8 approach sequence, which signaled the opening of the New Horizons Jupiter encounter.

    Even in these early approach images, Jupiter shows different face than what previous visiting spacecraft -- such as Voyager 1, Galileo and Cassini -- have seen. Regions around the equator and in the southern tropical latitudes seem remarkably calm, even in the typically turbulent 'wake' behind the Great Red Spot.

    The New Horizons science team will scrutinize these major meteorological features -- including the unexpectedly calm regions -- to understand the diverse variety of dynamical processes on the solar system's largest planet. These include the newly formed Little Red Spot, the Great Red Spot and a variety of zonal features.

  8. The Formation Environment of Jupiter's Moons

    NASA Technical Reports Server (NTRS)

    Turner, Neal; Lee, Man Hoi; Sano, Takayoshi

    2012-01-01

    Do circumjovian disk models have conductivities consistent with the assumed accretion stresses? Broadly, YES, for both minimum-mass and gas-starved models: magnetic stresses are weak in the MM models, as needed to keep the material in place. Stresses are stronger in the gas-starved models, as assumed in deriving the flow to the planet. However, future minimum-mass modeling may need to consider the loss of dust-depleted gas from the surface layers to the planet. The gas-starved models should have stress varying in radius. Dust evolution is a key process for further study, since the recombination occurs on the grains.

  9. The Formation Environment of Jupiter's Moons

    NASA Technical Reports Server (NTRS)

    Turner, Neal; Lee, Man Hoi; Sano, Takayoshi

    2012-01-01

    Do circumjovian disk models have conductivities consistent with the assumed accretion stresses? Broadly, YES, for both minimum-mass and gas-starved models: magnetic stresses are weak in the MM models, as needed to keep the material in place. Stresses are stronger in the gas-starved models, as assumed in deriving the flow to the planet. However, future minimum-mass modeling may need to consider the loss of dust-depleted gas from the surface layers to the planet. The gas-starved models should have stress varying in radius. Dust evolution is a key process for further study, since the recombination occurs on the grains.

  10. Restored pictures of ganymede, moon of jupiter.

    PubMed

    Frieden, B R; Swindell, W

    1976-03-26

    Restored pictures of Ganymede have been produced that have some identifiably reliable features and some identifiable artifacts. The latter arise from artifacts in parts of the red image data. Among the presumably reliable features are some mare-like objects (perhaps with some internal structure), and a few rather large, bright rings. Whether the latter are ice, or arise from near-specular reflection from smooth surface features, is left for future investigation. One of the restoring methods used, maximum entropy, has been shown to be applicable to moderately extended images. In view of its short time requirements (30 seconds per picture), the method should be applicable to moderately larger images, for example with twice the given number of data points.

  11. Restored pictures of Ganymede, moon of Jupiter

    NASA Technical Reports Server (NTRS)

    Frieden, B. R.; Swindell, W.

    1976-01-01

    The paper discusses results of an attempt to restore two blurred pictures of Ganymede taken by Pioneer 10 through a blue filter and a red filter. The mathematical formulation of the restoration problem is outlined, it is noted that both conventional linear filtering and the maximum-entropy algorithm were employed as restoration techniques, and the two methods are described. The original blurred pictures are reproduced along with the two restorations of each image. The restored images are found to exhibit some mare-like features as well as a few large bright rings, possibly ice ridges. The results obtained with the two restoration techniques are compared, and it is concluded that the maximum-entropy method is more advantageous than linear methods in applications to moderately extended images.

  12. JUICE/RPWI/JENRAGE: a low frequency radio imager at Jupiter

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Kasaba, Y.; Bergman, J. E. S.; Zarka, P.; Lamy, L.; Hess, S. L. G.; Rothkaehl, H.

    2015-10-01

    The JENRAGE (Jovian Environment Radio Astronomy and Ganymede Exploration) experiment of the Radio and Plasma Waves Instrument (RPWI) on-board JUICE (Jupiter Icy Moon Explorer) is a sensitive, and versatile radio instrument. It will observe radio waves ranging from 80 kHz to 45 MHz at a 100 Msample per second aquisition rate. The instrument is composed of set of 3 electrical dipoles (developed by the Polish team), connected to low noise preamplifiers and conditioning analog filters (built by the Japanese team), then sampled and digitally filtererd into ~300 kHz bands (digital part developed by the Swedish team). This international project is coordinated by B. Cecconi and Y. Kasaba, both co-PI of JUICE/RPWI. Although the radio antenna connected to this instrument have no intrinsic directivity, the JENRAGE measurements can provide instantaneous direction of arrival, flux density and polarization degree of the observed radio waves. Hence, the JENRAGE can be described as an full-sky radio imager. As the instrument provides direction of arrival, radio sources can be located with some assumption on the propagation between the source and the observer. Hence, it is possible to produce radio source maps and correlate them with observations at other wavelengths, such as UV or IR observations of the auroral regions of Jupiter. The flux and polarization measurements together with the time- frequency shape of the radio emissions can also be used to identify the radio emission processes. These features have shown their capabilities on Cassini, with the RPWS/HFR instrument. We will present the JUICE/RPWI/JENRAGE design and the science objectives. Additional science topics linked to the icy satellites, which are currently being assessed, will also be presented.

  13. Habitability potential of satellites around Jupiter and Saturn

    NASA Astrophysics Data System (ADS)

    Coustenis, Athena; Raulin, Francois; Encrenaz, Therese; Grasset, Olivier; Solomonidou, Anezina

    2016-07-01

    biomarkers. Currently, for Titan and Enceladus, geophysical models try to explain the possible existence of an oceanic layer that decouples the mantle from the icy crust. Titan has further been suggested to be a possible cryovolcanic world due to the presence of local complex volcanic-like geomorphology and the indications of surface albedo changes with time [7,8]. Such dynamic activity that would most probably include tidal heating, possible internal convection, and ice tectonics, is believed to be a pre-requisite of a habitable planetary body as it allows the recycling of minerals and potential nutrients and provides localized energy sources. In one of our geophysical studies [4], we have showed that tidal forces are a constant and significant source of internal deformation on Titan and the interior liquid water ocean can be relatively warm for reasonable amounts of ammonia concentrations, thus completing the set of parameters needed for a truly habitable planetary body. If the silicate mantles of Europa and Ganymede and the liquid sources of Titan and Enceladus are geologically active as on Earth, giving rise to the equivalent of hydrothermal systems, the simultaneous presence of water, geodynamic interactions, chemical energy sources and a diversity of key chemical elements may fulfill the basic conditions for habitability. Such habitability indications from bodies at distances of 10 AU, are essential discoveries brought to us by space exploration and which have recently revolutionized our perception of habitability in the solar system. In the solar system's neighborhood, such potential habitats can only be investigated with appropriate designed space missions, like JUICE (JUpiter ICy moon Explorer) for Ganymede and Europa [9]. JUICE is an ESA mission to Jupiter and its icy moons, recently selected to launch in 2022. Other future mission concepts are being studied for exploring the moons around Saturn. References: [1] Coustenis, A., Encrenaz, Th., in "Life Beyond Earth

  14. Reflecting on Icy Rhea

    NASA Image and Video Library

    2009-11-03

    Bright sunlight on Rhea shows off the cratered surface of Saturn second largest moon in this image captured by NASA Cassini Orbiter. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 21, 2009.

  15. Moon - False Color Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false-color mosaic of part of the Moon was constructed from 54 images taken by Galileo's imaging system as the spacecraft flew past the Moon on December 7, 1992. The mosaic images were processed to exaggerate the colors of the lunar surface for analytical purposes. Titanium-rich soils, typical of the Apollo 11 landing site, appear blue, as seen in Mare Tranquillitatis, left side; soils lower in titanium appear orange, as seen in Mare Serenitatis, center right. Most of the lunar highlands appear red, indicating their low titanium and iron composition. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

  16. Studying the Surfaces of the Icy Galilean Satellites With JIMO

    NASA Astrophysics Data System (ADS)

    Prockter, L.; Schenk, P.; Pappalardo, R.

    2003-12-01

    The Geology subgroup of the Jupiter Icy Moons Orbiter (JIMO) Science Definition Team (SDT) has been working with colleagues within the planetary science community to determine the key outstanding science goals that could be met by the JIMO mission. Geological studies of the Galilean satellites will benefit from the spacecraft's long orbital periods around each satellite, lasting from one to several months. This mission plan allows us to select the optimal viewing conditions to complete global compositional and morphologic mapping at high resolution, and to target geologic features of key scientific interest at very high resolution. Community input to this planning process suggests two major science objectives, along with corresponding measurements proposed to meet them. Objective 1: Determine the origins of surface features and their implications for geological history and evolution. This encompasses investigations of magmatism (intrusion, extrusion, and diapirism), tectonism (isostatic compensation, and styles of faulting, flexure and folding), impact cratering (morphology and distribution), and gradation (erosion and deposition) processes (impact gardening, sputtering, mass wasting and frosts). Suggested measurements to meet this goal include (1) two dimensional global topographic mapping sufficient to discriminate features at a spatial scale of 10 m, and with better than or equal to 1 m relative vertical accuracy, (2) nested images of selected target areas at a range of resolutions down to the submeter pixel scale, (3) global (albedo) mapping at better than or equal to 10 m/pixel, and (4) multispectral global mapping in at least 3 colors at better than or equal to 100 m/pixel, with some subsets at better than 30 m/pixel. Objective 2. Identify and characterize potential landing sites for future missions. A primary component to the success of future landed missions is full characterization of potential sites in terms of their relative age, geological interest, and

  17. Crescent Earth and Moon

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This picture of a crescent-shaped Earth and Moon -- the first of its kind ever taken by a spacecraft -- was recorded Sept. 18, 1977, by NASA's Voyager 1 when it was 7.25 million miles (11.66 million kilometers) from Earth. The Moon is at the top of the picture and beyond the Earth as viewed by Voyager. In the picture are eastern Asia, the western Pacific Ocean and part of the Arctic. Voyager 1 was directly above Mt. Everest (on the night side of the planet at 25 degrees north latitude) when the picture was taken. The photo was made from three images taken through color filters, then processed by the Jet Propulsion Laboratory's Image Processing Lab. Because the Earth is many times brighter than the Moon, the Moon was artificially brightened by a factor of three relative to the Earth by computer enhancement so that both bodies would show clearly in the print. Voyager 2 was launched Aug. 20, 1977, followed by Voyager 1 on Sept. 5, 1977, en route to encounters at Jupiter in 1979 and Saturn in 1980 and 1981. JPL manages the Voyager mission for NASA's Office of Space Science.

  18. The Earth & Moon

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During its flight, the Galileo spacecraft returned images of the Earth and Moon. Separate images of the Earth and Moon were combined to generate this view. The Galileo spacecraft took the images in 1992 on its way to explore the Jupiter system in 1995-97. The image shows a partial view of the Earth centered on the Pacific Ocean about latitude 20 degrees south. The west coast of South America can be observed as well as the Caribbean; swirling white cloud patterns indicate storms in the southeast Pacific. The distinct bright ray crater at the bottom of the Moon is the Tycho impact basin. The lunar dark areas are lava rock filled impact basins. This picture contains same scale and relative color/albedo images of the Earth and Moon. False colors via use of the 1-micron filter as red, 727-nm filter as green, and violet filter as blue. The Galileo project is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

  19. Crescent Earth and Moon

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This picture of a crescent-shaped Earth and Moon -- the first of its kind ever taken by a spacecraft -- was recorded Sept. 18, 1977, by NASA's Voyager 1 when it was 7.25 million miles (11.66 million kilometers) from Earth. The Moon is at the top of the picture and beyond the Earth as viewed by Voyager. In the picture are eastern Asia, the western Pacific Ocean and part of the Arctic. Voyager 1 was directly above Mt. Everest (on the night side of the planet at 25 degrees north latitude) when the picture was taken. The photo was made from three images taken through color filters, then processed by the Jet Propulsion Laboratory's Image Processing Lab. Because the Earth is many times brighter than the Moon, the Moon was artificially brightened by a factor of three relative to the Earth by computer enhancement so that both bodies would show clearly in the print. Voyager 2 was launched Aug. 20, 1977, followed by Voyager 1 on Sept. 5, 1977, en route to encounters at Jupiter in 1979 and Saturn in 1980 and 1981. JPL manages the Voyager mission for NASA's Office of Space Science.

  20. The Earth and Moon

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During its flight, the Galileo spacecraft returned images of the Earth and Moon. Separate images of the Earth and Moon were combined to generate this view. The Galileo spacecraft took the images in 1992 on its way to explore the Jupiter system in 1995-97. The image shows a partial view of the Earth centered on the Pacific Ocean about latitude 20 degrees south. The west coast of South America can be observed as well as the Caribbean; swirling white cloud patterns indicate storms in the southeast Pacific. The distinct bright ray crater at the bottom of the Moon is the Tycho impact basin. The lunar dark areas are lava rock filled impact basins. This picture contains same scale and relative color/albedo images of the Earth and Moon. False colors via use of the 1-micron filter as red, 727-nm filter as green, and violet filter as blue. The Galileo project is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

  1. Geophysical Consequences of Icy Satellite Rigidity

    NASA Astrophysics Data System (ADS)

    Nimmo, Francis

    2006-09-01

    The interior structures of icy satellites are typically deduced by measuring J2 from flybys, and then using the hydrostatic assumption (i.e. zero rigidity) to deduce the polar moment of inertia. While this technique works well for the Earth, it fails dismally for Mars and the Moon. The recent detection of regional gravity anomalies on Ganymede [1] suggests loads supported by elastic stresses. Thus, the use of the hydrostatic assumption to derive structures for cold, icy bodies like Callisto [2] or Mimas should be treated with great caution [3]. The rigidity of icy satellites is important for at least three other reasons. Firstly, it controls (via the Love number k2) the degree of tidal heating experienced. For equal Love numbers, Enceladus and Europa would experience very similar diurnal tidal amplitudes. However, because Enceladus has a smaller radius it is likely to behave in a more rigid fashion than Europa, resulting in less tidal heating. Conventional (diurnal) tidal generation of the observed heat flux at Enceladus' south pole [4] requires Q/k2 of order 100, implying a relatively soft interior. Secondly, satellite rigidity controls both the magnitude of loads which are potentially capable of causing satellite reorientation, and the size of the opposing fossil bulge [5]. Finally, the near-surface rigidity (elastic thickness) influences, and may be deduced from, observations of the scale and morphology of surface tectonic features [6]. [1] Palguta et al. Icarus 180, 428-441, 2006 [2] Anderson et al. Icarus 153, 157-161, 2001 [3] McKinnon Icarus 130, 540-543, 1997 [4] Spencer et al., Science 311, 1401-1405, 2006 [5] Nimmo and Pappalardo, Nature 441, 614-616, 2006 [6] Nimmo and Schenk, J. Struct. Geol. in press.

  2. Massive Gas Cloud Around Jupiter

    NASA Technical Reports Server (NTRS)

    2003-01-01

    An innovative instrument on NASA's Cassini spacecraft makes the space environment around Jupiter visible, revealing a donut-shaped gas cloud encircling the planet.

    The image was taken with the energetic neutral atom imaging technique by the Magnetospheric Imaging Instrument on Cassini as the spacecraft flew past Jupiter in early 2001 at a distance of about 10 million kilometers (6 million miles). This technique provides information about a source by detecting neutral atoms emitted by the source, comparable to how a camera reveals information about an object by detecting photons coming from the object.

    The central object in this image represents energetic neutral atom emissions from Jupiter itself. The outer two objects represent emissions from a donut-shaped cloud, or torus, that shares an orbit with Jupiter's moon Europa. The cloud's emissions appear dot-like because of the viewing angle. The torus is viewed edge-on, and the image is brightest at the line-of-sight angles that pass through the greatest volume of it.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages Cassini for NASA's Office of Space Science, Washington, D.C.

  3. Massive Gas Cloud Around Jupiter

    NASA Technical Reports Server (NTRS)

    2003-01-01

    An innovative instrument on NASA's Cassini spacecraft makes the space environment around Jupiter visible, revealing a donut-shaped gas cloud encircling the planet.

    The image was taken with the energetic neutral atom imaging technique by the Magnetospheric Imaging Instrument on Cassini as the spacecraft flew past Jupiter in early 2001 at a distance of about 10 million kilometers (6 million miles). This technique provides information about a source by detecting neutral atoms emitted by the source, comparable to how a camera reveals information about an object by detecting photons coming from the object.

    The central object in this image represents energetic neutral atom emissions from Jupiter itself. The outer two objects represent emissions from a donut-shaped cloud, or torus, that shares an orbit with Jupiter's moon Europa. The cloud's emissions appear dot-like because of the viewing angle. The torus is viewed edge-on, and the image is brightest at the line-of-sight angles that pass through the greatest volume of it.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages Cassini for NASA's Office of Space Science, Washington, D.C.

  4. Aurora Borealis on Jupiter

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image, taken by NASA's Galileo spacecraft, shows the darkside of Jupiter, the part not illuminated by sunlight. The curved line crossing from the lower left to the upper right is the auroral arc on the horizon. With north at the top of the image, the central part of the auroral arc has a latitude of 57 degrees north. When this same region was imaged 30 seconds later, the central part had changed. The left and right boxes below show a magnified view of the central region at the earlier and later times, respectively. The aurora is dynamic on Jupiter, just as it is here on Earth. The eerie, glowing light is created when molecules in the upper atmosphere are struck by charge particles from the space around Jupiter. Fluctuations in the charged particle flow cause variations in the auroral emission.

    This image was part of a multi-instrument set of observations made as Galileo flew through a region of space rich in charged particles. The particles follow the magnetic field and, in this case, the spacecraft was flying through the particular field line that was imaged. With these observations, scientists hope to learn more about the particles and their interaction with the molecules in the atmosphere. This image provides a severe test of the camera optics. The overexposed region at the lower right is the illuminated part of the planet, which is much brighter than the aurora. When light from this region is scattered into the telescope, it creates a diffuse background. The long exposure subjects the detector to more cosmic rays than usual. These create spikes, the bright dots that are sprinkled throughout the image. These images were taken in the clear filter of the solid state imaging (CCD) system aboard the Galileo spacecraft on Nov. 5, 1996. Each pixel subtends a square about 30 kilometers (18.5 miles) throughout the image. The range is 1.433 million kilometers (0.89 million miles).

    Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 7, 1995

  5. Time Series of Jupiter Aurora

    NASA Image and Video Library

    1998-06-10

    These mosaics of Jupiter's night side show the Jovian aurora at approximately 45 minute intervals as the auroral ring rotated with the planet below the spacecraft. The images were obtained by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. during its eleventh orbit of Jupiter. The auroral ring is offset from Jupiter's pole of rotation and reaches the lowest latitude near 165 degrees west longitude. The aurora is hundreds of kilometers wide, and when it crosses the edge of Jupiter, it is about 250 kilometers above the planet. As on Earth, the auroral emission is caused by electrically charged particles striking atoms in the upper atmosphere from above. The particles travel along Jupiter's magnetic field lines, but their origin is not fully understood. The field lines where the aurora is most intense cross the Jovian equator at large distances (many Jovian radii) from the planet. The faint background throughout the image is scattered light in the camera. This stray light comes from the sunlit portion of Jupiter, which is out of the image. In multispectral observations the aurora appears red, consistent with how atomic hydrogen in Jupiter's atmosphere would glow. Galileo's unique perspective allows it to view the night side of the planet at short range, revealing details that cannot be seen from Earth. These detailed features are time dependent, and can be followed in this sequence of Galileo images. In the first mosaic, the auroral ring is directly over Jupiter's limb and is seen "edge on." In the fifth mosaic, the auroral emission is coming from several distinct bands. This mosaic also shows the footprint of the Io flux tube. Volcanic eruptions on Jupiter's moon, Io, spew forth particles that become ionized and are pulled into Jupiter's magnetic field to form an invisible tube, the Io flux tube, between Jupiter and Io. The bright circular feature towards the lower right may mark the location where these energetic particles impact Jupiter. Stars

  6. Icy Tendrils from Enceladus

    NASA Astrophysics Data System (ADS)

    Mitchell, C. J.; Porco, C.; Weiss, J. W.

    2015-12-01

    We extend our previous work (Mitchell et al., 2015) in simulating thelarge-scale, sinuous structures, dubbed 'tendrils', observed inCassini ISS images of the E ring near Enceladus. We follow thetrajectories of particles launched from the geyser sources locatedacross the moon's south polar terrain (Porco et al., 2014), assumingthe velocity distribution of Ingersoll and Ewald, (2011), andincluding forces due to the gravity of Saturn and Enceladus, as wellas Saturn's magnetic and electric fields. Charging currents arisingfrom interactions with magnetospheric plasma and Solar UV radiationare also included. The simulations are used to produce syntheticimages which we compare to Cassini ISS tendril images taken in 2006and 2013. We found that specific subsets of geysers appear to be thesources of identifiable tendril features present in the images.However, there remained features not captured by our initialsimulations: a shift in longitude for the brightest part of thetendrils and two features which only appear in some images.In this initial work, we neglected Enceladus' orbital eccentricity aswell as the periodicity and phase of the variability in geyseringactivity recently discovered and attributed to a ~5-hour delay in thediurnally variable tidal stresses at the surface (Nimmo et al. 2014).And we made no attempt to do a photometric determination of the masslost from the moon into orbit around Saturn.We will report on our progress in rectifying these inadequacies. Wewill present the result of including Enceladus's orbital eccentricity,as well as a diurnally variable particle flux out of each geyser, inaccord with the observed plume variability. Eventually, we will usethe absolute brightness of the tendrils, together with a photometricmodel and information on the particle size distribution from our work,and the work of other Cassini teams on E ring particles, to arrive atthe amount of mass leaving the moon and entering Saturn orbit.Mitchell et al., 2015, AJ, 149, 156

  7. The inner satellites of Jupiter

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Thomas, P.; Synott, S.

    1981-01-01

    The Jupiter moon Amalthea and the smaller satellites J1, J2, and J3, discovered by Voyagers 1 and 2, are discussed under the collective appellation of 'inner satellites', which distinguishes them from the Galilean satellites and the outer satellites, J6-J13. Amalthea is a dark, irregular body on which two large craters are visible, with an estimated surface gravity of 5-7 cm/sec-squared. It is speculated that Amalthea's unique color/reflectance characteristics are due to prolonged charged particle and high-velocity micrometeoroid exposure. Dimensional data are presented for J1-3.

  8. Hubble Gallery of Jupiter's Galilean Satellites

    NASA Technical Reports Server (NTRS)

    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/

  9. Hubble Captures Rare Triple-Moon Conjunction

    NASA Image and Video Library

    2017-09-28

    Three moons and their shadows parade across Jupiter near the end of the event at 07:10 UT on January 24, 2015. Europa has entered the frame at lower left. Slower-moving Callisto is above and to the right of Europa. Fastest-moving Io is approaching the eastern limb of the planet. Europa's shadow is toward the left side of the image and Callisto's shadow to the right. (The moons' orbital velocities are proportionally slower with increasing distance from the planet.) Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) More info: Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io. Jupiter's four largest moons can commonly be seen transiting the face of the giant planet and casting shadows onto its cloud tops. However, seeing three moons transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that was too far from Jupiter in angular separation to be part of the conjunction. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  10. Distribution of CO2 ice on the large moons of Uranus and evidence for compositional stratification of their near-surfaces

    NASA Astrophysics Data System (ADS)

    Cartwright, R. J.; Emery, J. P.; Rivkin, A. S.; Trilling, D. E.; Pinilla-Alonso, N.

    2015-09-01

    The surfaces of the large uranian satellites are characterized by a mixture of H2O ice and a dark, potentially carbon-rich, constituent, along with CO2 ice. At the mean heliocentric distance of the uranian system, native CO2 ice should be removed on timescales shorter than the age of the Solar System. Consequently, the detected CO2 ice might be actively produced. Analogous to irradiation of icy moons in the Jupiter and Saturn systems, we hypothesize that charged particles caught in Uranus' magnetic field bombard the surfaces of the uranian satellites, driving a radiolytic CO2 production cycle. To test this hypothesis, we investigated the distribution of CO2 ice by analyzing near-infrared (NIR) spectra of these moons, gathered using the SpeX spectrograph at NASA's Infrared Telescope Facility (IRTF) (2000-2013). Additionally, we made spectrophotometric measurements using images gathered by the Infrared Array Camera (IRAC) onboard the Spitzer Space Telescope (2003-2005). We find that the detected CO2 ice is primarily on the trailing hemispheres of the satellites closest to Uranus, consistent with other observations of these moons. Our band parameter analysis indicates that the detected CO2 ice is pure and segregated from other constituents. Our spectrophotometric analysis indicates that IRAC is not sensitive to the CO2 ice detected by SpeX, potentially because CO2 is retained beneath a thin surface layer dominated by H2O ice that is opaque to photons over IRAC wavelengths. Thus, our combined SpeX and IRAC analyses suggest that the near-surfaces (i.e., top few 100 μm) of the uranian satellites are compositionally stratified. We briefly compare the spectral characteristics of the CO2 ice detected on the uranian moons to icy satellites elsewhere, and we also consider the most likely drivers of the observed distribution of CO2 ice.

  11. ICIS Enforcement Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  12. ICIS Contacts Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  13. ICIS Activity Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  14. ICIS Limit Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  15. ICIS Permit Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  16. ICIS DMR Subject Area Model

    EPA Pesticide Factsheets

    The Integrated Compliance Information System (ICIS) is a web-based system that provides information for the federal enforcement and compliance (FE&C) and the National Pollutant Discharge Elimination System (NPDES) programs.

  17. Integrated Compliance Information System (ICIS)

    EPA Pesticide Factsheets

    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 system that supports both management and programmatic requirements of the Enforcement and Compliance programs.

  18. Radiation belts of jupiter: a second look.

    PubMed

    Fillius, R W; McIlwain, C E; Mogro-Campero, A

    1975-05-02

    The outbound leg of the Pioneer 11 Jupiter flyby explored a region farther from the equator than that traversed by Pioneer 10, and the new data require modification or augmentation of the magnetodisk model based on the Pioneer 10 flyby. The inner moons of Jupiter are sinks of energetic particles and sometimes sources. A large spike of particles was found near lo. Multiple peaks occurred in the particle fluxes near closest approach to the planet; this structure may be accounted for by a complex magnetic field configuration. The decrease in proton flux observed near minimum altitude on the Pioneer 10 flyby appears attributable to particle absorption by Amalthea.

  19. Seeding Life on the Moons of the Outer Planets via Lithopanspermia

    PubMed Central

    Sigurdsson, Steinn; House, Christopher H.

    2013-01-01

    Abstract Material from the surface of a planet can be ejected into space by a large impact and could carry primitive life-forms with it. We performed n-body simulations of such ejecta to determine where in the Solar System rock from Earth and Mars may end up. We found that, in addition to frequent transfer of material among the terrestrial planets, transfer of material from Earth and Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect that such transfers were most likely to occur during the Late Heavy Bombardment or during the ensuing 1–2 billion years. At this time, the icy moons were warmer and likely had little or no ice shell to prevent meteorites from reaching their liquid interiors. We also note significant rates of re-impact in the first million years after ejection. This could re-seed life on a planet after partial or complete sterilization by a large impact, which would aid the survival of early life during the Late Heavy Bombardment. Key Words: Panspermia—Impact—Meteorites—Titan—Europa. Astrobiology 13, 1155–1165. PMID:24341459

  20. Seeding life on the moons of the outer planets via lithopanspermia.

    PubMed

    Worth, R J; Sigurdsson, Steinn; House, Christopher H

    2013-12-01

    Material from the surface of a planet can be ejected into space by a large impact and could carry primitive life-forms with it. We performed n-body simulations of such ejecta to determine where in the Solar System rock from Earth and Mars may end up. We found that, in addition to frequent transfer of material among the terrestrial planets, transfer of material from Earth and Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect that such transfers were most likely to occur during the Late Heavy Bombardment or during the ensuing 1-2 billion years. At this time, the icy moons were warmer and likely had little or no ice shell to prevent meteorites from reaching their liquid interiors. We also note significant rates of re-impact in the first million years after ejection. This could re-seed life on a planet after partial or complete sterilization by a large impact, which would aid the survival of early life during the Late Heavy Bombardment.

  1. Io in Front of Jupiter

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Jupiter's four largest satellites, including Io, the golden ornament in front of Jupiter in this image from NASA's Cassini spacecraft, have fascinated Earthlings ever since Galileo Galilei discovered them in 1610 in one of his first astronomical uses of the telescope.

    Images from Cassini that will be released over the next several days capture each of the four Galilean satellites in their orbits around the giant planet.

    This true-color composite frame, made from narrow angle images taken on Dec. 12, 2000, captures Io and its shadow in transit against the disk of Jupiter. The distance of the spacecraft from Jupiter was 19.5 million kilometers (12.1 million miles). The image scale is 117 kilometers (73 miles) per pixel.

    The entire body of Io, about the size of Earth's Moon, is periodically flexed as it speeds around Jupiter and feels, as a result of its non-circular orbit, the periodically changing gravitational pull of the planet. The heat arising in Io's interior from this continual flexure makes it the most volcanically active body in the solar system, with more than 100 active volcanoes. The white and reddish colors on its surface are due to the presence of different sulfurous materials. The black areas are silicate rocks.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  2. Surfing Jupiter

    NASA Image and Video Library

    2017-05-25

    Waves of clouds at 37.8 degrees latitude dominate this three-dimensional Jovian cloudscape, courtesy of NASA's Juno spacecraft. JunoCam obtained this enhanced-color picture on May 19, 2017, at 5:50 UTC from an altitude of 5,500 miles (8,900 kilometers). Details as small as 4 miles (6 kilometers) across can be identified in this image. The small bright high clouds are about 16 miles (25 kilometers) across and in some areas appear to form "squall lines" (a narrow band of high winds and storms associated with a cold front). On Jupiter, clouds this high are almost certainly composed of water and/or ammonia ice. https://photojournal.jpl.nasa.gov/catalog/PIA21646

  3. Jupiter Wallpaper

    NASA Image and Video Library

    2017-03-08

    When team members from NASA's Juno mission invited the public to process JunoCam images, they did not anticipate that they would receive back such beautiful, creative expressions of art. The oranges and grayed-out regions of blue-green in this tiled and color-enhanced image resemble a color scheme much like Romantic era paintings, but more abstract. The lack of discreet objects to focus on allows the mind to seek familiar Earthly shapes, and the brightest spots seem to draw the eye. Citizen scientist Eric Jorgensen created this Jovian artwork with a JunoCam image taken when the spacecraft was at an altitude of 11,100 miles (17,800 kilometers) above Jupiter's cloudtops on Dec. 11, 2016 at 9:22 a.m. PT (12:22 p.m. ET). http://photojournal.jpl.nasa.gov/catalog/PIA21385

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Moon - False Color Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false-color mosaic was constructed from a series of 53 images taken through three spectral filters by Galileo's imaging system as the spacecraft flew over the northern regions of the Moon on December 7, 1992. The part of the Moon visible from Earth is on the left side in this view. The color mosaic shows compositional variations in parts of the Moon's northern hemisphere. Bright pinkish areas are highlands materials, such as those surrounding the oval lava-filled Crisium impact basin toward the bottom of the picture. Blue to orange shades indicate volcanic lava flows. To the left of Crisium, the dark blue Mare Tranquillitatis is richer in titanium than the green and orange maria above it. Thin mineral-rich soils associated with relatively recent impacts are represented by light blue colors; the youngest craters have prominent blue rays extending from them. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

  6. Moon - False Color Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false-color mosaic was constructed from a series of 53 images taken through three spectral filters by Galileo's imaging system as the spacecraft flew over the northern regions of the Moon on December 7, 1992. The part of the Moon visible from Earth is on the left side in this view. The color mosaic shows compositional variations in parts of the Moon's northern hemisphere. Bright pinkish areas are highlands materials, such as those surrounding the oval lava-filled Crisium impact basin toward the bottom of the picture. Blue to orange shades indicate volcanic lava flows. To the left of Crisium, the dark blue Mare Tranquillitatis is richer in titanium than the green and orange maria above it. Thin mineral-rich soils associated with relatively recent impacts are represented by light blue colors; the youngest craters have prominent blue rays extending from them. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

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

    NASA Astrophysics Data System (ADS)

    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

  8. Jupiter - Io In Front of Jupiter Turbulent Clouds

    NASA Image and Video Library

    1996-11-13

    This photograph of the southern hemisphere of Jupiter was obtained by Voyager 2 on June 25, 1979, at a distance of 12 million kilometers (8 million miles). The Voyager spacecraft is rapidly nearing the giant planet, with closest approach to occur at 4:23 pm PDT on July 9. Seen in front of the turbulent clouds of the planet is Io, the innermost of the large Galilean satellites of Jupiter. Io is the size of our moon. Voyager discovered in early March that Io is the most volcanically active planetary body known in the solar system, with continuous eruptions much larger than any that take place on the Earth. The red, orange, and yellow colors of Io are thought to be deposits of sulfur and sulfur compounds produced in these eruptions. The smallest features in either Jupiter or Io that can be distinguished in this picture are about 200 kilometers (125 miles) across; this resolution, it is not yet possible to identify individual volcanic eruptions. Monitoring of the erupture activity of Io by Voyager 2 will begin about July 5 and will extend past the encounter July 9. http://photojournal.jpl.nasa.gov/catalog/PIA00371

  9. Photon-counting lidars for contiguous high resolution topographic mapping of planets and moons

    NASA Astrophysics Data System (ADS)

    Degnan, John J.

    2007-08-01

    moon Europa, and the Saturnian moons, Titan and Enceladus. A recently completed study for NASA's Jupiter Icy Moons Orbiter (JIMO) mission concluded that the three primary Jovian moons (Ganymede, Callisto, and Europa) could be contiguously and globally mapped, at few meter horizontal resolutions, by a photon-counting lidar in a matter of months from orbital altitudes of 100 km. Work is also underway to include a technical demonstration of a photon-counting lidar ("Swath Mapper") on NASA's ICESat-II mission, which is scheduled for a 2011 launch into a 600 km orbit. Swath Mapper would use a single low energy, high repetition rate laser (nominally 1 mJ@ 10 kHz = 10W) to measure surface topography along 16 uniformly spaced ground tracks spread over roughly 2.1 km.

  10. Re-Analysis of the Solar Phase Curves of the Icy Galilean Satellites

    NASA Technical Reports Server (NTRS)

    Domingue, Deborah; Verbiscer, Anne

    1997-01-01

    Re-analysis of the solar phase curves of the icy Galilean satellites demonstrates that the quantitative results are dependent on the single particle scattering function incorporated into the photometric model; however, the qualitative properties are independent. The results presented here show that the general physical characteristics predicted by a Hapke model (B. Hapke, 1986, Icarus 67, 264-280) incorporating a two parameter double Henyey-Greenstein scattering function are similar to the predictions given by the same model incorporating a three parameter double Henyey-Greenstein scattering function as long as the data set being modeled has adequate coverage in phase angle. Conflicting results occur when the large phase angle coverage is inadequate. Analysis of the role of isotropic versus anisotropic multiple scattering shows that for surfaces as bright as Europa the two models predict very similar results over phase angles covered by the data. Differences arise only at those phase angles for which there are no data. The single particle scattering behavior between the leading and trailing hemispheres of Europa and Ganymede is commensurate with magnetospheric alterations of their surfaces. Ion bombardment will produce more forward scattering single scattering functions due to annealing of potential scattering centers within regolith particles (N. J. Sack et al., 1992, Icarus 100, 534-540). Both leading and trailing hemispheres of Europa are consistent with a high porosity model and commensurate with a frost surface. There are no strong differences in predicted porosity between the two hemispheres of Callisto, both are consistent with model porosities midway between that deduced for Europa and the Moon. Surface roughness model estimates predict that surface roughness increases with satellite distance from Jupiter, with lunar surface roughness values falling midway between those measured for Ganymede and Callisto. There is no obvious variation in predicted surface

  11. Very High Resolution Image of Icy Cliffs on Europa and Similar Scales on Earth (Providence, RI)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The top image is a very high resolution view of the Conamara Chaos region on Jupiter's moon Europa, showing an area where icy plates have been broken apart and moved around laterally. The top of this image is dominated by corrugated plateaus ending in icy cliffs over a hundred meters (a few hundred feet) high. Debris piled at the base of the cliffs. The bottom image is an aerial photograph of downtown Providence, Rhode Island at the same scale. The bright white circular feature in the top center of the Providence image is an indoor hockey rink, and one can find many craters in the Europa image about the same size. Blocks of debris which have fallen from the cliffs on the Europa image are about the same size as houses seen in the Providence image, and the largest blocks are almost as large as the Rhode Island state capitol building (large white building in upper left of Providence image). A fracture that runs horizontally across the center of the Europa image is about the same width as the freeway which runs along the bottom of the Providence image.

    North is to the top right of the Europa image, and the sun illuminates the surface from the east. The Europa image is centered at approximately 9 degrees north latitude and 274 degrees west longitude. The images each cover an area approximately 1.7 kilometers by 4 kilometers (1 mile by 2.5 miles). The resolution is 9 meters (30 feet) per picture element. The Europa image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by the solid state imaging system on NASA's Galileo spacecraft.

    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. Convection-Driven Resurfacing on Icy Satellites

    NASA Astrophysics Data System (ADS)

    Barr, Amy

    2015-04-01

    Ridge and trough terrain, characterized by kilometer-scale sub-parallel ridges and troughs, is found in a variety of settings on the icy satellites of the solar system. Examples include Ganymede's grooved terrain [1], Europa's bands [2,3], Miranda's coronae [4,5], and swaths of ridges and troughs in the northern plains of Enceladus [6]. The fault spacing implies a shallow brittle/ductile depth and thus, a high thermal gradient at the time of formation [e.g., 7]. I will show that similar rheological parameters can give rise to the heat flows and deformation rates inferred for the formation of many examples of ridge and trough terrain. These results suggest that convection in ice mantles with weak surfaces can explain the formation of these terrains, just as convection in Earth's mantle, beneath a weakened crust, can drive surface deformation. References: [1] Pappalardo, R. T. et al., 2004. in Jupiter, Cambridge Univ. Press, pp.363. [2] Prockter, L. M. et al., 2002. JGR 107, 5028. [3] Stempel, M. M. et al., 2005. Icarus 177, 297. [4] Pappalardo, R. T. et al., 1997. JGR 102, 13369. [5] Hammond, N. P. and A. C. Barr, 2014. Geology 42, 931-934. [6] Bland, M. et al., 2007. Icarus 192, 92. [7] Nimmo, F. et al., 2002. GRL 29 62-1.

  13. Energetic charged particle interactions at icy satellites

    NASA Astrophysics Data System (ADS)

    Nordheim, T.; Hand, K. P.; Paranicas, C.; Howett, C.; Hendrix, A. R.

    2016-12-01

    Satellites embedded within planetary magnetospheres are typically exposed to bombardment by charged particles, from thermal plasma to more energetic particles at radiation belt energies. At many planetary satellites, energetic charged particles are typically unimpeded by patchy atmospheres or induced satellite magnetic fields and instead are stopped in the surface itself. Most of these primaries have ranges in porous water ice that are at most centimeters, but some of their secondary photons, emitted during the deceleration process, can reach meter depths [Paranicas et al., 2002, 2004; Johnson et al., 2004]. Examples of radiation-induced surface alteration includes sputtering, radiolysis and grain sintering, processes that are capable of significantly altering the physical properties of surface material. Thus, accurate characterization of energetic charged particle weathering at icy satellites is crucial to a more comprehensive understanding of these bodies. At Saturn's inner mid-size moons remote sensing observations by several instruments onboard the Cassini spacecraft have revealed distinct weathering patterns which have been attributed to energetic electron bombardment of the surface [Howett et al., 2011, 2012, 2014; Schenk et al., 2011; Paranicas et al., 2014]. In the Jovian system, radiolytic production of oxidants has been invoked as a potential source of energy for life which may reside in the sub-surface ocean of its satellite Europa [Johnson et al., 2003; Hand et al., 2007; Vance et al., 2016]. Here we will discuss the near-surface energetic charged particle environment of icy satellites, with particular emphasis on comparative studies between the Saturnian and Jovian systems and interpretation of remote sensing observations by instruments onboard missions such as Cassini and Galileo. In addition, we will discuss implications for surface sampling by future lander missions (e.g. the proposed Europa lander now under study).

  14. What do the compositions of the regular satellites of Jupiter and Saturn tell us?

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Podolak, M.

    2012-12-01

    Models for the formation of the regular satellites of Jupiter and Saturn are hampered by our lack of understanding of the turbulent state of the subnebula and the gas-inflow rate [1]. Fortunately, it is possible to construct regular satellite formation models that are not dependent on specific choices for these parameters [2,3]. These two approaches treat planetesimal dynamics explicitly (which is a model requirement [1]), and also account for the angular momentum budget of the regular satellites. The inner satellites of Jupiter, Io and Europa, are depleted of volatiles either due to the temperature gradient in the subnebula [4,5], collisional processes involving differentiated objects [6], and/or the Laplace resonance. The observed densities of the Saturnian regular satellites are not compatible with solar compositions [7]. The inner satellites of Saturn (inside of Titan) include a stochastic compositional component (e.g., Tethys vs. Enceladus) due to collisional processes deep in the kronian gravitational-potential well; however, such an argument can not be applied to faraway and isolated Iapetus. ([8] consider a collisional scattering origin for Iapetus, but we favor the model we present here.) The bulk compositional and size similarities between Ganymede, Callisto and Titan argue strongly in favor of non-stochastic processes for these satellites. Therefore, the non-stochastic masses and densities of the large, outer regular satellites of Jupiter and Saturn (Ganymede, Callisto, Titan and Iapetus) provide the most directly useful constraints for satellite formation models. Observations indicate that Kuiper Belt Objects (KBOs) are of different composition than the regular satellites of Jupiter and Saturn. The simplest explanation of the observations is that the subnebulae of these giant planets are enriched in water-ice compared to the outer solar nebula [7]. The contrast between icy Iapetus and rocky Phoebe reinforces the interpretation of Phoebe as a moon

  15. Juno Captures Jupiter Glow in Infrared Light

    NASA Image and Video Library

    2016-09-02

    As NASA's Juno spacecraft approached Jupiter on Aug. 27, 2016, the Jovian Infrared Auroral Mapper (JIRAM) instrument captured the planet's glow in infrared light. The video is composed of 580 images collected over a period of about nine hours while Jupiter completed nearly a full rotation on its axis. The video shows the two parts composing the JIRAM imager: the lower one, in a red color scale, is used for mapping the planet's thermal emission at wavelengths around 4.8 microns; the upper one, in a blue color scale, is used to map the auroras at wavelengths around 3.45 microns. In this case the exposure time of the imager was optimized to observe the planet's thermal emission. However, it is possible to see a faint aurora and Jupiter's moon Io approaching the planet. The Great Red Spot is also visible just south of the planet's equator. A movie is available at http://photojournal.jpl.nasa.gov/catalog/PIA21036

  16. The 1981 Jupiter Orbiter Probe mission

    NASA Technical Reports Server (NTRS)

    Moore, J. W.; Hyde, J. R.; Van Allen, J. A.; Nunamaker, R. S.

    1976-01-01

    Plans for the 1981 Jupiter Orbiter Probe (JOP) mission are presented in some detail. The need for a Jupiter entry probe, remote sensing of the planet, and an orbiter, in addition to flybys, is made clear. Launch hardware, using the Space Shuttle flight system and Interim Upper Stage, is described, along with scientific tasks laid out for the entry probe and the orbiter. Combined analysis of the Jovian magnetosphere and other orbiter missions calls for a two-part orbiter with one part spun and the other de-spun. Related design problems and solutions are described and diagrammed. Jovian moon flybys and orbiter path adjustments by subsequent earth-launched flybys are discussed. The importance of Jupiter data for solar system evolution and possible analysis of early stages of stellar evolution or of a binary system are also treated.

  17. Detection and analysis of Jupiter's decametric micropulses

    NASA Technical Reports Server (NTRS)

    Lebo, G. R.

    1972-01-01

    The occurrence of Jupiter's decametric radio emission can be correlated with the central meridian longitude of Jupiter as if the active regions were radio transmitters placed at fixed longitudes on its surface. These active regions are commonly called sources and are labelled Source A, Jovian longitude = 200 deg, Source B = 100 deg and Source C =300 deg. These sources are not always active. However, they can be turned-on if Jupiter's innermost Galilean moon, Io, is in the right phase. In fact, if Io is found 90 deg from superior geocentric conjunction (maximum eastern elongation) and if source B is simultaneously on the central meridian, source B radiation is almost guaranteed, whereas source C radiation is highly likely when Io is found 240 deg from superior geocentric conjunction. Source A radiation is largely independent of Io's position. Interestingly, the Io-related radio storms contain unusually rapid events that can only be properly studied using wide-band techniques.

  18. The meteorology of Jupiter

    NASA Technical Reports Server (NTRS)

    Ingersoll, A. P.

    1976-01-01

    From the point of view of meteorology the most important differences between Jupiter and the earth are related to the fact that Jupiter has an appreciable internal energy source and probably lacks a solid surface. The composition and vertical structure of the Jovian atmosphere is considered along with the composition of Jovian cloud particles, turbulence in Jupiter's atmosphere, data on the horizontal structure and motions of the atmosphere, and questions related to the longevity of Jupiter's clouds. Attention is given to the barotropic characteristics of Jupiter's atmosphere, the radiation balance in the atmosphere of the earth and of Jupiter, and studies of the Great Red Spot.

  19. Europa Planetary Protection for Juno Jupiter Orbiter

    NASA Technical Reports Server (NTRS)

    Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

    2010-01-01

    NASA's Juno mission launched in 2011 and will explore the Jupiter system starting in 2016. Juno's suite of instruments is designed to investigate the atmosphere, gravitational fields, magnetic fields, and auroral regions. Its low perijove polar orbit will allow it to explore portions of the Jovian environment never before visited. While the Juno mission is not orbiting or flying close to Europa or the other Galilean satellites, planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design.The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

  20. Europa Planetary Protection for Juno Jupiter Orbiter

    NASA Technical Reports Server (NTRS)

    Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

    2010-01-01

    NASA's Juno mission launched in 2011 and will explore the Jupiter system starting in 2016. Juno's suite of instruments is designed to investigate the atmosphere, gravitational fields, magnetic fields, and auroral regions. Its low perijove polar orbit will allow it to explore portions of the Jovian environment never before visited. While the Juno mission is not orbiting or flying close to Europa or the other Galilean satellites, planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design.The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

  1. September moons

    NASA Astrophysics Data System (ADS)

    Gavin, M.

    2003-12-01

    Although Mars, through unprecedented proximity, caused great interest in its surface features this summer, its two tiny moons were worthy imaging targets too. A few degrees away was Uranus with Oberon and Titania and further west Neptune and satellite Triton.

  2. Moon Rise

    NASA Image and Video Library

    Aboard the International Space Station in May 2012, Expedition 31 astronaut Don Pettit opened the shutters covering the cupola observation windows in time to watch the moon rise. The time-lapse sce...

  3. Spinning Moons

    NASA Image and Video Library

    2015-11-10

    Most inner moons in the solar system keep one face pointed toward their central planet; this frame from an animation by NASA New Horizons shows that certainly isnt the case with the small moons of Pluto, which behave like spinning tops. Pluto is shown at center with, in order, from smaller to wider orbit: Charon, Styx, Nix, Kerberos, Hydra. http://photojournal.jpl.nasa.gov/catalog/PIA20152

  4. Rhea: Full Moon

    NASA Image and Video Library

    2005-12-06

    This giant mosaic reveals Saturn's icy moon Rhea in her full, crater-scarred glory. This view consists of 21 clear-filter images and is centered at 0.4 degrees south latitude, 171 degrees west longitude. The giant Tirawa impact basin is seen above and to the right of center. Tirawa, and another basin to its southwest, are both covered in impact craters, indicating they are quite ancient. The bright, approximately 40-kilometer-wide (25-mile) ray crater seen in many Cassini views of Rhea is located on the right side of this mosaic (at 12 degrees south latitude, 111 degrees west longitude). See PIA07764 for a close-up view of the eastern portion of the bright, ray crater. There are few signs of tectonic activity in this view. However, the wispy streaks on Rhea that were seen at lower resolution by NASA's Voyager and Cassini spacecraft, were beyond the western (left) limb from this perspective. In high-resolution Cassini flyby images of Dione, similar features were identified as fractures caused by extensive tectonism. Rhea is Saturn's second-largest moon, at 1,528 kilometers (949 miles) across. The images in this mosaic were taken with the Cassini spacecraft narrow-angle camera during a close flyby on Nov. 26, 2005. The images were acquired as Cassini approached the moon at distances ranging from 79,190 to 58,686 kilometers (49,206 to 36,466 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of about 19 degrees. Image scale in the mosaic is 354 meters (1,161 feet) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA07763

  5. Jupiter in Color, by Cassini

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This color image of Jupiter was taken by the camera onboard NASA's Cassini spacecraft when it was 81.3 million kilometers (50.5 million miles) from the planet. It is composed of images taken in the blue, green, and red regions of the spectrum and is therefore close to the true color of Jupiter that one would see through an Earth-based telescope.

    The image is remarkably similar to images taken by NASA's Voyager 1 and 2 spacecraft more than 21 years ago, illustrating the stability of Jupiter's weather patterns. The parallel dark and bright bands and many other large-scale features are quasi-permanent structures that survive despite the intense small-scale activity ongoing in the atmosphere. The longevity of the large-scale features is an intrinsic property of the atmospheric flows on a gaseous planet such as Jupiter, with no solid surface. Smaller features, such as those in the dark bands north and south of the equator, are observed to form and disappear in a few days.

    Everything visible on the planet is a cloud. Unlike Earth, where only water condenses to form clouds, Jupiter has several cloud-forming substances in its atmosphere. The updrafts and downdrafts bring different mixtures of these substances up from below, leading to clouds of different colors. The bluish features just north of the equator are regions of reduced cloud cover, similar to the place where the Galileo atmospheric probe entered in 1995. They are called 'hot spots' because the reduced cloud cover allows heat to escape from warmer, deeper levels in the atmosphere.

    Jupiter's moon Europa is seen at the right, casting a shadow on the planet. Scientists believe Europa holds promise of a liquid ocean beneath its surface.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science

  6. Cylindrical Projection of Jupiter

    NASA Image and Video Library

    1996-01-29

    This computer generated map of Jupiter was made from 10 color images of Jupiter taken Feb. 1, 1979, by NASA Voyager 1, during a single, 10 hour rotation of the planet. http://photojournal.jpl.nasa.gov/catalog/PIA00011

  7. Jupiter Eye to Io

    NASA Image and Video Library

    2000-12-12

    This image taken by NASA Cassini spacecraft on Dec. 1, 2000, shows details of Jupiter Great Red Spot and other features that were not visible in images taken earlier, when Cassini was farther from Jupiter.

  8. Ulysses at Jupiter

    NASA Image and Video Library

    2004-02-05

    An artist impression of Ulysses spacecraft at Jupiter. Ulysses used Jupiter powerful gravity to hurl it out of the Plane of the Ecliptic where most planets and satellites orbit so it could study the polar regions of the Sun.

  9. Plans and Combined Operations of the Flight Elements of the Europa Jupiter System Mission (EJSM)

    NASA Astrophysics Data System (ADS)

    Erd, Christian; Clark, K.; Ejsm System Teams

    2010-05-01

    The Europa Jupiter System Mission (EJSM) is a joint NASA-ESA mission candidate, where ESA would provide the Jupiter Ganymede Orbiter (JGO) and NASA would provide the Jupiter Europa Orbiter (JEO). Both spacecraft are foreseen to be launched in 2020, allowing for a joint exploration of the Jovian system, and the Galilean moons. The planning of the development, implementation and combined science phase will be described in the poster.

  10. Satellite Footprints Seen in Jupiter Aurora

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This is a spectacular NASA Hubble Space Telescope close-up view of an electric-blue aurora that is eerily glowing one half billion miles away on the giant planet Jupiter. Auroras are curtains of light resulting from high-energy electrons racing along the planet's magnetic field into the upper atmosphere. The electrons excite atmospheric gases, causing them to glow. The image shows the main oval of the aurora, which is centered on the magnetic north pole, plus more diffuse emissions inside the polar cap.

    Though the aurora resembles the same phenomenon that crowns Earth's polar regions, the Hubble image shows unique emissions from the magnetic 'footprints' of three of Jupiter's largest moons. (These points are reached by following Jupiter's magnetic field from each satellite down to the planet).

    Auroral footprints can be seen in this image from Io (along the lefthand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede's auroral footprint). These emissions, produced by electric currents generated by the satellites, flow along Jupiter's magnetic field, bouncing in and out of the upper atmosphere. They are unlike anything seen on Earth.

    This ultraviolet image of Jupiter was taken with the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998. In this ultraviolet view, the aurora stands out clearly, but Jupiter's cloud structure is masked by haze.

    December 14, 2000 inaugurates an intensive two weeks of joint observation of Jupiter's aurora by Hubble and the Cassini spacecraft. Cassini will make its closest approach to Jupiter enroute to a July 2004 rendezvous with Saturn. A second campaign in January 2001 will consist of Hubble images of Jupiter's day-side aurora and Cassini images of Jupiter's night-side aurora, obtained just after Cassini has flown past Jupiter. The team will develop computer models that predict how the aurora operates, and this will yield new insights into the effects of the solar wind

  11. Voyager 2 Jupiter encounter

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A NASA News Release is presented which contains the following: (1) general release; (2) two views of Voyager 2 flight past Jupiter; (3) Voyager mission summary; (4) Voyager 1 science results; (5) Jupiter science objectives; (6) Jupiter the planet and its satellites; (7) Voyager experiments; (8) planet comparison; (9) a list of Voyager science investigators and (10) the Voyager team.

  12. Focus on the Moon.

    ERIC Educational Resources Information Center

    Byrd, Deborah

    1980-01-01

    Described is the observation of the moon with binoculars. Descriptions of the thin crescent moon, three-day-old moon, five-day-old moon, first quarter moon, 10-day-old moon and the full moon are presented and characteristics of each phase are included. (DS)

  13. Focus on the Moon.

    ERIC Educational Resources Information Center

    Byrd, Deborah

    1980-01-01

    Described is the observation of the moon with binoculars. Descriptions of the thin crescent moon, three-day-old moon, five-day-old moon, first quarter moon, 10-day-old moon and the full moon are presented and characteristics of each phase are included. (DS)

  14. Coherent backscatter model for the unusual radar reflectivity of icy satellites

    NASA Technical Reports Server (NTRS)

    Hapke, Bruce; Blewett, David

    1991-01-01

    The coherent backscatter model is investigated experimentally by means of an analog to examine the nature of the radar reflectivity of icy satellites. The laboratory analog involves the examination of He-Ne laser light with a wavelength of 0.633 microns reflected from 0.497-micron polystyrene beads suspended in water. A photomultiplier and a polarizing filter are employed to observe the radar at phase angles greater than zero which are extrapolated to infer observation at zero phase angle. The polarization angles measured at optical frequencies are found to be equivalent to those observed in the radar data. The results suggest that the regoliths of the icy satellites consist of matrices of small complex refractive indices which contain scatterers separated by distances of the order of a wavelength. The experiment explains the high reflectivity of Jupiter's icy satellites which results in the observation of narrow opposition-effects peaks at optical frequencies.

  15. Low Force Icy Regolith Penetration Technology

    NASA Technical Reports Server (NTRS)

    Metzger, P. T.; Galloway, G. M.; Mantovani, J. G.; Zacny, K.; Zacny, Kris; Craft, Jack

    2011-01-01

    Recent data from the Moon, including LCROSS data, indicate large quantities of water ice and other volatiles frozen into the soil in the permanently shadowed craters near the poles. If verified and exploited, these volatiles will revolutionize spaceflight as an inexpensive source of propellants and other consumables outside Earth's gravity well. This report discusses a preliminary investigation of a method to insert a sensor through such a soiVice mixture to verify the presence, nature, and concentration of the ice. It uses percussion to deliver mechanical energy into the frozen mixture, breaking up the ice and decompacting the soil so that only low reaction forces are required from a rover or spacecraft to push the sensor downward. The tests demonstrate that this method may be ideal for a small platform in lunar gravity. However, there are some cases where the system may not be able to penetrate the icy soil, and there is some risk ofthe sensor becoming stuck so that it cannot be retracted, so further work is needed. A companion project (ISDS for Water Detection on the Lunar Surface) has performed preliminary investigation of a dielectric/thermal sensor for use with this system.

  16. Jupiter's Gossamer Rings Explained.

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2003-05-01

    Over the past several years, Galileo measurements and groundbased imaging have drastically improved our knowledge of Jupiter's faint ring system. We now recognize that the ring consists of four components: a main ring 7000km wide, whose inner edge blossoms into a vertically-extended halo, and a pair of more tenuous Gossamer rings, one associated with each of the small moons Thebe and Amalthea. When viewed edge on, the Gossamer rings appear as diaphanous disks whose thicknesses agree with the vertical excursions of the inclined satellites from the equatorial plane. In addition, the brightness of each Gossamer ring drops off sharply outside the satellite orbits. These correlations allowed Burns etal (1999, Science, 284, 1146) to argue convincingly that the satellites act as sources of the dusty ring material. In addition, since most material is seen inside the orbits of the source satellites, an inwardly-acting dissipative force such as Poynting-Robertson drag is implicated. The most serious problem with this simple and elegant picture is that it is unable to explain the existence of a faint swath of material that extends half a jovian radius outward from Thebe. A key constraint is that this material has the same thickness as the rest of the Thebe ring. In this work, we identify the mechanism responsible for the outward extension: it is a shadow resonance, first investigated by Horanyi and Burns (1991, JGR, 96, 19283). When a dust grain enters Jupiter's shadow, photoelectric processes shut down and the grain's electric charge becomes more negative. The electromagnetic forces associated with the varying charge cause periodic oscillations in the orbital eccentricity and semimajor axis as the orbital pericenter precesses. This results in a ring which spreads both inward and outward of its source satellite while preserving its vertical thickness - just as is observed for the Thebe ring. Predictions of the model are: i) gaps of micron-sized material interior to Thebe and

  17. The Moon

    NASA Astrophysics Data System (ADS)

    Warren, P. H.; Taylor, G. J.

    Exciting recent developments in lunar geochemistry include the discovery that some lunar magmas had earthlike contents of water and remote-sensing evidence for crustal heterogeneity, including regions rich in magnesian spinel, regions of nearly pure anorthosite, regions of high Mg/Fe, and regions of evolved, silicic composition. The magma ocean hypothesis continues to be tested and refined. Concerns about the initial neodymium isotopic ratio of the ferroan anorthosites have been allayed by evidence that the whole Moon (and Mars and Earth) may have a depleted Nd/Sm ratio. However, age results still show no clear distinction between the ferroan anorthosites and the oldest Mg-suite rocks. Stable isotopic data show remarkably close kinship between the Moon and Earth, so close that it poses difficulty for most existing giant impact scenarios of lunar origin, as these models imply that the Moon forms mainly out of material spalled from a large, late interloping body.

  18. Moon Convention

    NASA Image and Video Library

    2015-03-23

    People with similar jobs or interests hold conventions and meetings, so why shouldn't moons? Pandora, Prometheus, and Pan -- seen here, from right to left -- also appear to be holding some sort of convention in this image. Some moons control the structure of nearby rings via gravitational "tugs." The cumulative effect of the moon's tugs on the ring particles can keep the rings' edges from spreading out as they are naturally inclined to do, much like shepherds control their flock. Pan is a prototypical shepherding moon, shaping and controlling the locations of the inner and outer edges of the Encke gap through a mechanism suggested in 1978 to explain the narrow Uranian rings. However, though Prometheus and Pandora have historically been called "the F ring shepherd moons" due to their close proximity to the ring, it has long been known that the standard shepherding mechanism that works so well for Pan does not apply to these two moons. The mechanism for keeping the F ring narrow, and the roles played -- if at all -- by Prometheus and Pandora in the F ring's configuration are not well understood. This is an ongoing topic for study by Cassini scientists. This view looks toward the sunlit side of the rings from about 29 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 2, 2015. The view was obtained at a distance of approximately 1.6 million miles (2.6 million kilometers) from the rings and at a Sun-ring-spacecraft, or phase, angle of 86 degrees. Image scale is 10 miles (15 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/pia18306

  19. Europa's Interaction with the Magnetosphere of Jupiter

    NASA Astrophysics Data System (ADS)

    Khurana, Krishan K.; Jia, Xianzhe; Paranicas, Chris; Cassidy, Timothy A.; Hansen, Kenneth C.

    2013-04-01

    Galileo's observations of magnetic field in the vicinity of Europa have shown that Europa does not possess an appreciable internal magnetic field. However, Europa strongly modifies its plasma and magnetic field environment by directly interacting with the magnetosphere of Jupiter. The plasma interactions cause the absorption of Jovian plasma by the moon, pick-up of newly formed ions from the exospheres of the moon, plasma diversion by electrodynamic (Alfvén wing) interaction and the formation of a long wake in the downstream region. In addition to the electrodynamic interactions, Europa also displays electromagnetic induction response to the rotating field of Jupiter presumably from the conducting presence of global salty liquid oceans inside the moon. Galileo successfully encountered Europa 10 times during its mission. We are developing quantitative 3-D MHD models of plasma interactions of Europa with Jupiter's magnetosphere. In these models we include the effects of plasma pick-up and plasma interaction with a realistic exosphere as well as the contribution of the electromagnetic induction. We will present results of these quantitative models and show that the plasma interaction is strongest when Europa is located at the center of Jupiter's current sheet. We find that plasma mass loading rates are extremely variable over time. We will investigate various mechanisms by which such variability in mass-loading could be produced including episodically enhanced sputtering from trapped gaseous molecules in ice and enhanced plasma interaction with a vent(s) generated dense exosphere. The new model will aid researchers in planning observations from future missions such as JUICE and Europa flagship mission.

  20. Tidal Evolution and Hydrothermal Activity in IcyWorlds

    NASA Astrophysics Data System (ADS)

    Vance, S.; Hussmann, H.

    2008-09-01

    The tidal heating that sustains a subsurface ocean in Europa likely varied in intensity through the moons history due to the exchange of orbital angular momentum with the innermost Galilean satellite, Io [1]. Tidal interactions elsewhere in the solar system — e.g. in Neptunes moon Triton, and in Kuiper belt systems such as Pluto-Charon and the 2003 EL61 system (Santa-Rudolph-Blitzen) — highlight the potential for vigorously heated subsurface oceans and thus the existence of hydrothermal systems in icy worlds. Understanding the extent and nature of hydrothermal activity in such systems is important for assessing the availability of essential elements and organic compounds necessary sustain and, possibly, originate life [2, 3, 4, 5, 6, 7]. During periods of low tidal heating in such systems, hydrothermalism driven by serpentinization (reaction of water with ultramafic rock) may be extensive, with implications for seafloor production of hydrogen, methane and other potential nutrients, and elements necessary to originate and support life in icy world oceans. For Enceladus, an anomalously dense satellite for its size, radiogenic heating and overburden pressure in the mantle are sufficiently low to permit fracturing of the entirety of the moons rocky interior on long time scales [8]. Estimates of methane production from serpentinization of Enceladus interior, based on measured fluxes from the Lost City Hydrothermal Field [9], are an order of magnitude greater than fluxes observed at Enceladuss south polar plume by the Cassini Ion Neutral Mass Spectrometer [10]. For the largest icy worlds in the Solar System — Titan, Ganymede and Callisto—pressures at and below the H2Orock interface are likely too high to permit the formation of microfractures, so an alternative explanation is required if methane is endogenous. Aqueous alteration may be augmented from the above estimates if altered crust is rejuvenated during periods of increased tidal dissipation. Crustal

  1. New Views of Jupiter's Rings

    NASA Astrophysics Data System (ADS)

    Burns, J. A.

    1998-09-01

    Jupiter's rings are the archetype of ethereal planetary rings (very-low optical-depth bands containing micron-sized "dust"). As a result of much improved observations by Galileo (Ockert-Bell* -- most citations are et al. and Icarus in press* or this meeting) and Keck (de Pater*), we now understand the nature of such rings. The ring has three components: a 104 km-thick toroidal halo (1.4-1.7 RJ; normal optical depth t = 10-6), a thin main ring (1.7-1.8 RJ; t = 10-6), and a pair of exterior gossamer rings (1.8-3.5RJ; t = 10-7). The main ring has patchy ( 20-30 percent) brightness. The ring is reddish and its particles satisfy a -2.5 differential power-law size distribution. Because particle lifetimes are brief, the rings must be continually regenerated, by collisions into parent bodies, which may be unseen or may be the known small ring-moons (Thomas*, Simonelli). The gossamer ring seems to be collisional ejecta derived from the ring-moons Amalthea and Thebe, and evolving inward by Poynting-Robertson drag (Burns). The particles drift through many electromagnetic resonances, clustering around synchronous orbit, which produce jumps in the particles' inclinations (Hamilton). The main ring is probably debris from Adrastea and Metis, which orbit in the equatorial plane. The halo particles are driven vertically by electromagnetic forces, which may be resonant (Schaffer & Burns) or not (Horanyi & Cravens). When halo orbits become highly distorted, particles are lost into Jupiter. Similar faint rings may be attendant to all small, close-in satellites (Showalter).

  2. Strong tidal dissipation in Io and Jupiter from astrometric observations.

    PubMed

    Lainey, Valéry; Arlot, Jean-Eudes; Karatekin, Ozgür; Van Hoolst, Tim

    2009-06-18

    Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k(2)/Q = 0.015 +/- 0.003, where k(2) is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k(2)/Q = (1.102 +/- 0.203) x 10(-5)) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

  3. Strong tidal dissipation in Io and Jupiter from astrometric observations

    NASA Astrophysics Data System (ADS)

    Lainey, Valéry; Arlot, Jean-Eudes; Karatekin, Özgür; van Hoolst, Tim

    2009-06-01

    Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k2/Q = 0.015+/-0.003, where k2 is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k2/Q = (1.102+/-0.203)×10-5) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

  4. Strong Tidal Dissipation In Io And Jupiter From Astrometric Observations

    NASA Astrophysics Data System (ADS)

    Lainey, Valery; Arlot, J.; Karatekin, O.; Van Hoolst, T.

    2009-09-01

    Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k2/Q = 0.015+/-0.003, where k2 is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k2/Q = (1.102+/-0.203) X 10-5) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Technologies for Icy Bodies Access

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.; Anderson, F. S.; French, L. C.; Green, J. R.; Jones, J. A.; Lane, A. L.; Leger, P. C.; Zimmerman, W. F.

    2001-01-01

    Recent events in planetary exploration have profoundly changed the way both space scientists and the public regard the solar system and our place in it. These events include the Galileo data suggesting subsurface oceans in the Jovian system, ever stronger suggestions of near-surface water on Mars, as well as the complex structure observed for the Mars polar caps. And, of course, interest in icy cometary bodies is as old as humankind. Finally, the Mars north polar cap may conceivably cover and protect an ancient ocean floor, an obvious candidate ancient or extant habitat. In short, our interest in searching for life embraced early on the search for liquid water, and that has led us to an additional appreciation for water ice as both a commonplace partner with liquid water and as an issue to be addressed in the exploration of a host of interesting sites. In general, the spectrum of specialized technology for space exploration has not yet been broadened to include the requirements brought about by exploration of icy sites. We argue that technologies for access, operations, and science in icy solar system sites must be examined and their prioritized development initiated in order to successfully plan missions to these compelling sites over the next two decades. Additional information is contained in the original extended abstract.

  7. Chemical Composition of Icy Satellite Surfaces

    NASA Astrophysics Data System (ADS)

    Dalton, J. B.; Cruikshank, D. P.; Stephan, K.; McCord, T. B.; Coustenis, A.; Carlson, R. W.; Coradini, A.

    2010-06-01

    Much of our knowledge of planetary surface composition is derived from remote sensing over the ultraviolet through infrared wavelength ranges. Telescopic observations and, in the past few decades, spacecraft mission observations have led to the discovery of many surface materials, from rock-forming minerals to water ice to exotic volatiles and organic compounds. Identifying surface materials and mapping their distributions allows us to constrain interior processes such as cryovolcanism and aqueous geochemistry. The recent progress in understanding of icy satellite surface composition has been aided by the evolving capabilities of spacecraft missions, advances in detector technology, and laboratory studies of candidate surface compounds. Pioneers 10 and 11, Voyagers I and II, Galileo, Cassini and the New Horizons mission have all made significant contributions. Dalton (Space Sci. Rev., 2010, this issue) summarizes the major constituents found or inferred to exist on the surfaces of the icy satellites (cf. Table 1 from Dalton, Space Sci. Rev., 2010, this issue), and the spectral coverage and resolution of many of the spacecraft instruments that have revolutionized our understanding (cf. Table 2 from Dalton, Space Sci. Rev., 2010, this issue). While much has been gained from these missions, telescopic observations also continue to provide important constraints on surface compositions, especially for those bodies that have not yet been visited by spacecraft, such as Kuiper Belt Objects (KBOs), trans-Neptunian Objects (TNOs), Centaurs, the classical planet Pluto and its moon, Charon. In this chapter, we will discuss the major satellites of the outer solar system, the materials believed to make up their surfaces, and the history of some of these discoveries. Formation scenarios and subsequent evolution will be described, with particular attention to the processes that drive surface chemistry and exchange with interiors. Major similarities and differences between the

  8. Compositional Mapping of Planetary moons by Mass Spectrometry of Dust Ejecta

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Gruen, E.; Horanyi, M.; Kempf, S.; Krüger, H.; Schmidt, J.; Spahn, F.; Srama, R.; Sternovsky, Z.; Trieloff, M.

    2011-12-01

    Classical methods to analyze the surface composition of planetary objects from a space craft are IR and gamma ray spectroscopy and neutron backscatter measurements. We present a complementary method to analyze rocky or icy dust particles as samples of planetary objects from where they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets - they are enshrouded in clouds of ballistic dust particles. In situ mass spectroscopic analysis of these grains impacting on to a detector on a spacecraft reveals their composition as characteristic samples of planetary surfaces at flybys or from an orbiter. The well established approach of dust detection by impact ionization has recently shown its capabilities by analyzing ice particles expelled by subsurface salt water on Saturn's moon Enceladus. Applying the method on micro-meteoroid ejecta of less active moons would allow for the qualitative and quantitative analysis of a huge number of samples from various surface areas, thus combining the advantages of remote sensing and a lander. Utilizing the heritage of the dust detectors onboard Ghiotto, Ulysses, Galileo, and Cassini a variety of improved, low-mass lab-models have been build and tested. They allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since achievable detection rates are on the order of thousand per orbit, an orbiter can create a compositional map of samples taken from a greater part of the surface. Flybies allow an investigation of certain surface areas of interest. Dust impact velocities are in general sufficiently high for impact ionization at orbiters about planetary objects with a radius of at least

  9. Jupiter and its Galilean Satellites as viewed from Mars

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-368, 22 May 2003

    Jupiter/Galilean Satellites: When Galileo first turned his telescope toward Jupiter four centuries ago, he saw that the giant planet had four large satellites, or moons. These, the largest of dozens of moons that orbit Jupiter, later became known as the Galilean satellites. The larger two, Callisto and Ganymede, are roughly the size of the planet Mercury; the smallest, Io and Europa, are approximately the size of Earth's Moon. This MGS MOC image, obtained from Mars orbit on 8 May 2003, shows Jupiter and three of the four Galilean satellites: Callisto, Ganymede, and Europa. At the time, Io was behind Jupiter as seen from Mars, and Jupiter's giant red spot had rotated out of view. This image has been specially processed to show both Jupiter and its satellites, since Jupiter, at an apparent magnitude of -1.8, was much brighter than the three satellites.

    A note about the coloring process: The MGS MOC high resolution camera only takes grayscale (black-and-white) images. To 'colorize' the image, a recent Cassini image acquired during its Jupiter flyby was used to color the MOC Jupiter picture. The procedure used was as follows: the Cassini color image was converted from 24-bit color to 8-bit color using a JPEG to GIF conversion program. The 8-bit color image was converted to 8-bit grayscale and an associated lookup table mapping each gray value of that image to a red-green-blue color triplet (RGB). Each color triplet was root-sum-squared (RSS), and sorted in increasing RSS value. These sorted lists were brightness-to-color maps for their respective images. Each brightness-to-color map was then used to convert the 8-bit grayscale MOC image to an 8-bit color image. This 8-bit color image was then converted to a 24-bit color image. The color image was edited to return the background to black. Jupiter's Galilean Satellites were not colored.

  10. Jupiter and its Galilean Satellites as viewed from Mars

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-368, 22 May 2003

    Jupiter/Galilean Satellites: When Galileo first turned his telescope toward Jupiter four centuries ago, he saw that the giant planet had four large satellites, or moons. These, the largest of dozens of moons that orbit Jupiter, later became known as the Galilean satellites. The larger two, Callisto and Ganymede, are roughly the size of the planet Mercury; the smallest, Io and Europa, are approximately the size of Earth's Moon. This MGS MOC image, obtained from Mars orbit on 8 May 2003, shows Jupiter and three of the four Galilean satellites: Callisto, Ganymede, and Europa. At the time, Io was behind Jupiter as seen from Mars, and Jupiter's giant red spot had rotated out of view. This image has been specially processed to show both Jupiter and its satellites, since Jupiter, at an apparent magnitude of -1.8, was much brighter than the three satellites.

    A note about the coloring process: The MGS MOC high resolution camera only takes grayscale (black-and-white) images. To 'colorize' the image, a recent Cassini image acquired during its Jupiter flyby was used to color the MOC Jupiter picture. The procedure used was as follows: the Cassini color image was converted from 24-bit color to 8-bit color using a JPEG to GIF conversion program. The 8-bit color image was converted to 8-bit grayscale and an associated lookup table mapping each gray value of that image to a red-green-blue color triplet (RGB). Each color triplet was root-sum-squared (RSS), and sorted in increasing RSS value. These sorted lists were brightness-to-color maps for their respective images. Each brightness-to-color map was then used to convert the 8-bit grayscale MOC image to an 8-bit color image. This 8-bit color image was then converted to a 24-bit color image. The color image was edited to return the background to black. Jupiter's Galilean Satellites were not colored.

  11. Polar Lightning on Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Images taken by the New Horizons Long-Range Reconnaissance Imager (LORRI) of Jupiter's night side showed lightning strikes. Each 'strike' is probably the cumulative brightness of multiple strikes. This is the first lightning seen at high latitudes on Jupiter; it demonstrates that convection is not confined to lower latitudes, implying an internal driving heat source. Their power is consistent with previous lightning measurements at Jupiter's lower latitudes, equivalent to extremely bright terrestrial 'super bolts.'

  12. Ammonia Clouds on Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Ammonia Ice Clouds on Jupiter

    In this movie, put together from false-color images taken by the New Horizons Ralph instrument as the spacecraft flew past Jupiter in early 2007, show ammonia clouds (appearing as bright blue areas) as they form and disperse over five successive Jupiter 'days.' Scientists noted how the larger cloud travels along with a small, local deep hole.

  13. Ammonia Clouds on Jupiter

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Ammonia Ice Clouds on Jupiter

    In this movie, put together from false-color images taken by the New Horizons Ralph instrument as the spacecraft flew past Jupiter in early 2007, show ammonia clouds (appearing as bright blue areas) as they form and disperse over five successive Jupiter 'days.' Scientists noted how the larger cloud travels along with a small, local deep hole.

  14. Jupiter - Solid or Gaseous? Ask Juno

    NASA Astrophysics Data System (ADS)

    Ackerman, J. A., Jr.

    2015-12-01

    Data from Cassini, Galileo, S-L 9 and Ulysses suggest Jupiter and Saturn are solid, frozen, Methane Gas Hydrate (MGH) planets. The bulk of these giants formed slow and cold by the natural accretion of snowflakes at their current orbital radii in the presence of methane, forming rigid incompressible bodies. MGH, (CH4)8(H2O)46 (d=0.9), is consistent with the abundances of the elements comprising the Earth (H>O>C). Their combined MGH comprises >250 earth-masses of H2O. Jupiter (d=1.33) incorporated most of the heavy elements in the nascent solar system, exemplified by an enormously enhanced D/H. The temperature excess of Jupiter's atmosphere is the result of an impact ~6,000 years BP, triggering an incredibly energetic fusion explosion which ejected the masses of the proto-Galilean moons. It also initiated a continuing fusion furnace in the crater producing a jet of hot gases extending >2x106 km, beyond Callisto. The jet has slowly diminished over 6,000 years, resulting in the differences in the four Galilean Moons. The mass ejection (ang. mom.) slowed Jupiter's rotation until ~1930, currently interpreted as a drift of the Great Red Spot. A diminishing fusion reaction (D + p → 3He + γ) continues to this day, producing Jupiter's atmospheric 'temperature excess'. Jupiter's rapid rotation deflects the rising vortex of hot gases from the fusion reaction horizontally, driving multiple zonal vortices, constrained by the frozen MGH surface <1000 km below the cloud tops. It appears as the tilted Great Red Spot (GRS), ~30,000 km to the west of the crater at 22 o S Lat., which has remained unchanged in the last 350 years - impossible due to the enormous Coliolis effect. Streams of 3He produced in the fusion reaction exiting Jupiter through the center of the GRS have been detected by the Galileo probe and orbiter, Ulysses, and Cassini. The fusion releases methane, also heavy elements which oxidize as they rise, producing the cloud-top colors. The MGH hypothesis explains the

  15. Jupiter System Observer

    NASA Technical Reports Server (NTRS)

    Senske, Dave; Kwok, Johnny

    2008-01-01

    This slide presentation reviews the proposed mission for the Jupiter System Observer. The presentation also includes overviews of the mission timeline, science goals, and spacecraftspecifications for the satellite.

  16. Jupiter Rocket Engine

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Engine for the Jupiter rocket. The Jupiter vehicle was a direct derivative of the Redstone. The Army Ballistic Missile Agency (ABMA) at Redstone Arsenal, Alabama, continued Jupiter development into a successful intermediate ballistic missile, even though the Department of Defense directed its operational development to the Air Force. ABMA maintained a role in Jupiter RD, including high-altitude launches that added to ABMA's understanding of rocket vehicle operations in the near-Earth space environment. It was knowledge that paid handsome dividends later.

  17. Mini Moons

    NASA Image and Video Library

    2014-10-20

    Are the moons tiny or are the rings vast? Both, in a way! The moons visible in this image from NASA Cassini spacecraft, Pandora and Atlas, are quite small by astronomical standards, but the rings are also enormous. From one side of the planet to the other, the A ring stretches over 170,000 miles 270,000 km. Pandora (50 miles, or 81 kilometers, across) orbits in the vicinity of the F ring, along with neighboring Prometheus, which is not visible in this image. These moons interact frequently with the narrow F ring, producing channels and streamers and other interesting features. Atlas (19 miles, or 30 kilometers across) orbits between the A ring and F ring in the Roche division. This view looks toward the sunlit side of the rings from about 34 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 17, 2014. The view was obtained at a distance of approximately 1.7 million miles (2.8 million kilometers) from Pandora and at a Sun-Pandora-spacecraft, or phase, angle of 110 degrees. Image scale is 11 miles (17 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18279

  18. Modeled Ion and Neutral Particle Distributions around Jupiter’s Moon Europa

    NASA Astrophysics Data System (ADS)

    Rubin, M.; Tenishev, V.; Hansen, K. C.; Jia, X.; Combi, M. R.; Gombosi, T. I.

    2009-12-01

    Jupiter’s moon Europa has a thin gravitationally bound neutral atmosphere which is mostly created through sputtering of high energy ions impacting on its icy surface. In a first step we will simulate the interaction of Europa with the Jovian magnetosphere by using the magnetohydrodynamics (MHD) model BATSRUS. Starting from the model used by Kabin et al. [JGR, Vol. 104, No. A9, (1999)] which accounts for the exospheric mass loading, ion-neutral charge exchange, and recombination we will further use the resistive MHD equations addressing the finite electron diffusivity. These results, including the magnetic field topology, are then used to calculate the Lorentz forces for our test particle Monte Carlo model. We use this model to simulate Europa’s plasma and neutral environment by tracking particles created on the moon’s surface by sputtering or sublimation, through dissociation and/or ionization in the atmosphere, or entering the system from Jupiter’s magnetosphere as high energy ions. Neutral particle trajectories are followed by solving the equation of motion in Europa’s gravity field whereas the ion population is additionally subject to the Lorentz force. We will show preliminary results of this work with application to the missions to the Jupiter system currently under consideration by NASA (JEO) and ESA (JGO).

  19. Ultraviolet Spectroscopy of the Surfaces of the Inner Icy Saturnian Satellites

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Hansen, C. J.

    2008-12-01

    The Cassini mission has provided a unique opportunity to make high-resolution, multi-spectral measurements of Saturn's icy moons, to investigate their surface compositions, processes and evolution. Here we present results from the Ultraviolet Imaing Spectrograph (UVIS). This instrument allows for the first measurements of the icy satellites in the extreme ultraviolet (EUV) to far-ultraviolet (FUV) wavelength range. The icy satellites of the Saturn system exhibit a remarkable amount of variability: Dark, battered Phoebe orbiting at a distant 200 RS, black-and-white Iapetus, the wispy streaks of Dione, cratered Rhea and Mimas, bright Tethys and geologically active Enceladus. Phoebe, Iapetus and Hyperion all orbit largely outside Saturn's magnetosphere, while the inner icy satellites Mimas, Enceladus, Dione Tethys and Rhea all orbit within the magnetosphere. Furthermore, the inner icy satellites all orbit within the E-ring - so the extent of exogenic effects on these icy satellites is wide-ranging. We present an overview of UVIS results from Tethys, Dione, Mimas, Enceladus and Rhea, focusing on surface investigations. We expect that the UV signatures of these icy satellites are strongly influenced not only by their water ice composition, but by external effects and magnetospheric environments. We study the FUV reflectance spectra to learn about the surface composition, map out water ice grain size variations, investigate effects of coating by E-ring grains, examine disk-resolved and hemispheric compositional and brightness variations, and investigate the presence of radiation products. This is new work: FUV spectra of surfaces have not been well-studied in the past. Spectra of the inner icy moons have been used to better develop spectral models, to further understand existing lab data of water ice and to help with understanding instrument performance. Analysis is challenged by a lack of laboratory data in this wavelength region, but intriguing results are being found

  20. Cratering at the Icy Satellites: Experimental Insights

    NASA Astrophysics Data System (ADS)

    Bruck Syal, M.; Schultz, P. H.

    2013-12-01

    Impact cratering processes play a central role in shaping the evolution of icy satellites and in guiding interpretations of various geologic features at these bodies. Accurate reconstruction of icy satellite histories depends in large part upon observed impact crater size-frequency distributions. Determining the extent of impact-induced thermal processing and the retention rates for impact-delivered materials of interest, e.g. organics, at these outer solar system moons is of fundamental importance for assessing their habitability and explaining differing geophysical histories. Hence, knowledge of how the impact process operates in ices or ice-rich materials is critically important. Recent progress in the development of water equations of state, coupled with increasingly efficient 3-D hydrocode calculations, has been used to construct careful numerical studies of melt and vapor generation for water ice targets. Complementary to this approach is experimental work to constrain the effects of differing ice target conditions, including porosity, rock mass fraction, and impact angle. Here we report on results from hypervelocity impact experiments (v~5.5 km/s) into water ice targets, performed at the NASA Ames Vertical Gun Range (AVGR). The setup at the AVGR allows for the use of particulate targets, which is useful for examining the effects of target porosity. Photometry and geophysical modeling both suggest that regolith porosity at the icy satellites is significant. We use a combination of half-space and quarter-space geometries, enabling analysis of the impact-generated vapor plume (half-space geometry), along with shock wave and transient crater growth tracking in a cross-sectional view (quarter-space geometry). Evaluating the impact-generated vapor from porous (φ = 0.5) and non-porous water ice targets provides an extension to previously published vapor production results for dolomite and CO2 ice targets. For the case of a 90 degree impact into porous ice, we

  1. Search for volatiles in the surface of icy satellites

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1986-01-01

    It is proposed to measure the reflectance spectra of the icy satellites of Jupiter, Saturn and Uranus in the spectral region 1.8 to 2.4 micrometers. These observations use the new Cooled Grating Array Spectrometer using a 32-element InSb photodiode array detector and produce spectra of higher resolution and precision than any data yet obtained; the ultimate scientific objective is to search for the signatures of methane clathrate, ammonium hydroxide or carbon monoxide clathrate (compounds predicted to exist on icy surfaces in the outer solar system by several theories of formation of these bodies) in the region of the spectrum where water ice has a relative maximum in reflectance. At the very least, these data will allow upper limits to be placed on the amount of these chemical species that can be present. The specific targets is Europa, Ganymede, Enceladus, Ariel and Titania, bodies that have the highest probability of having some or all of these volatiles on their surface according to current formation models.

  2. The Impact History Of The Moon

    NASA Technical Reports Server (NTRS)

    Cohen, B. A.

    2010-01-01

    The bombardment history of the Earth-Moon system has been debated since the first recognition that the circular features on the Moon may be impact craters. Because the lunar impact record is the only planetary impact record to be calibrated with absolute ages, it underpins our understanding of geologic ages on every other terrestrial planet. One of the more remarkable results to come out of lunar sample analyses is the hypothesis that a large number of impact events occurred on the Moon during a narrow window in time approximately 3.8 to 4.1 billion years ago (the lunar cataclysm ). Subsequent work on the lunar and martian meteorite suites; remote sensing of the Moon, Mars, asteroids, and icy satellites; improved dynamical modeling; and investigation of terrestrial zircons extend the cataclysm hypothesis to the Earth, other terrestrial planets, and possibly the entire solar system. Renewed US and international interest in exploring the Moon offers new potential to constrain the Earth-Moon bombardment history. This paper will review the lunar bombardment record, timing and mechanisms for cataclysmic bombardment, and questions that may be answered in a new age of exploration.

  3. Moon Waves and Moon Wakes

    NASA Image and Video Library

    2017-01-30

    This Cassini image features a density wave in Saturn's A ring (at left) that lies around 134,500 km from Saturn. Density waves are accumulations of particles at certain distances from the planet. This feature is filled with clumpy perturbations, which researchers informally refer to as "straw." The wave itself is created by the gravity of the moons Janus and Epimetheus, which share the same orbit around Saturn. Elsewhere, the scene is dominated by "wakes" from a recent pass of the ring moon Pan. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 34,000 miles (56,000 kilometers) from the rings and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (340 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21060

  4. Failure strength of icy lithospheres

    NASA Technical Reports Server (NTRS)

    Golombek, M. P.; Banerdt, W. B.

    1987-01-01

    Lithospheric strengths derived from friction on pre-existing fractures and ductile flow laws show that the tensile strength of intact ice under applicable conditions is actually an order of magnitude stronger than widely assumed. It is demonstrated that this strength is everywhere greater than that required to initiate frictional sliding on pre-existing fractures and faults. Because the tensile strength of intact ice increases markedly with confining pressure, it actually exceeds the frictional strength at all depths. Thus, icy lithospheres will fail by frictional slip along pre-existing fractures at yeild stresses greater than previously assumed rather than opening tensile cracks in intact ice.

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

    NASA Astrophysics Data System (ADS)

    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

  6. The Moon

    NASA Astrophysics Data System (ADS)

    Warren, P. H.

    2003-12-01

    Oxygen isotopic data suggest that there is a genetic relationship between the constituent matter of the Moon and Earth (Wiechert et al., 2001). Yet lunar materials are obviously different from those of the Earth. The Moon has no hydrosphere, virtually no atmosphere, and compared to the Earth, lunar materials uniformly show strong depletions of even mildly volatile constituents such as potassium, in addition to N2, O2, and H2O (e.g., Wolf and Anders, 1980). Oxygen fugacity is uniformly very low ( BVSP, 1981) and even the earliest lunar magmas seem to have been virtually anhydrous. These features have direct and far-reaching implications for mineralogical and geochemical processes. Basically, they imply that mineralogical diversity and thus variety of geochemical processes are subdued; a factor that to some extent offsets the comparative dearth of available data for lunar geochemistry.The Moon's gross physical characteristics play an important role in the more limited range of selenochemical compared to terrestrial geochemical processes. Although exceptionally large (radius=1,738 km) in relation to its parent planet, the Moon is only 0.012 times as massive as Earth. By terrestrial standards, pressures inside the Moon are feeble: the upper mantle gradient is 0.005 GPa km -1 (versus 0.033 GPa km -1 in Earth) and the central pressure is slightly less than 5 GPa. However, lunar interior pressures are sufficient to profoundly influence igneous processes (e.g., Warren and Wasson, 1979b; Longhi, 1992, 2002), and in this sense the Moon more resembles a planet than an asteroid.Another direct consequence of the Moon's comparatively small size was early, rapid decay of its internal heat engine. But the Moon's thermal disadvantage has resulted in one great advantage for planetology. Lunar surface terrains, and many of the rock samples acquired from them, retain for the most part characteristics acquired during the first few hundred million years of solar system existence. The

  7. Voyage to Jupiter.

    ERIC Educational Resources Information Center

    Morrison, David; Samz, Jane

    This publication illustrates the features of Jupiter and its family of satellites pictured by the Pioneer and the Voyager missions. Chapters included are: (1) "The Jovian System" (describing the history of astronomy); (2) "Pioneers to Jupiter" (outlining the Pioneer Mission); (3) "The Voyager Mission"; (4)…

  8. Speeding Towards Jupiter Pole

    NASA Image and Video Library

    2016-08-27

    Jupiter north polar region is coming into view as NASA Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles 703,000 kilometers away. http://photojournal.jpl.nasa.gov/catalog/PIA20895

  9. Jupiter Great Red Spot

    NASA Image and Video Library

    1997-09-07

    This view of Jupiter Great Red Spot is a mosaic of two images taken by NASA Galileo spacecraft. The Great Red Spot is a storm in Jupiter atmosphere and is at least 300 years-old. The image was taken on June 26, 1996. http://photojournal.jpl.nasa.gov/catalog/PIA00296

  10. Jupiter System Observer

    NASA Technical Reports Server (NTRS)

    Senske, Dave; Prockter, Louise

    2008-01-01

    This slide presentation reviews the scientific philosophy that is guiding the planning behind the Jupiter System Observer (JSO). The JSO would be a long-term platform for studying Jupiter and the complete Jovian system. The goal is to advance the understanding of the fundamental processes of planetary systems, their formation and evolution.

  11. Jupiter System Observer

    NASA Technical Reports Server (NTRS)

    Senske, Dave; Prockter, Louise

    2008-01-01

    This slide presentation reviews the scientific philosophy that is guiding the planning behind the Jupiter System Observer (JSO). The JSO would be a long-term platform for studying Jupiter and the complete Jovian system. The goal is to advance the understanding of the fundamental processes of planetary systems, their formation and evolution.

  12. Radiation belts of jupiter.

    PubMed

    Fillius, R W; McIlwain, C E

    1974-01-25

    Pioneer 10 counted relativistic electrons throughout the magnetosphere of Jupiter, with the greatest fluxes being inside 20 Jupiter radii. The peak flux of electrons with energy greater than 50 million electron volts was 1.3 x 10(7) per square centimeter per second at the innermost penetration of the radiation belts.

  13. Jupiter: its captured satellites.

    PubMed

    Bailey, J M

    1971-08-27

    Because of the small size and irregular orbits of the seven outer satellites of Jupiter, it is often assumed that they were derived by capture. The conditions whereby Jupiter can capture satellites have therefore been examined. Relationships derived on the basis of the three-body problem for planets in elliptical orbits enable the dimensions of the capture orbits around Jupiter to be calculated. It is found that Jupiter may capture satellites through the inner Lagrangian point when at perihelion or at aphelion. Captures at perihelion should give rise to satellites in direct orbits of 11.48 x 10(6) kilometers and capture at aphelion to retrograde orbits of 21.7 x 10(6) kilometers. The correspondence with the seven outer satellites suggests that Jupiter VI, VIl, and X in direct orbits at 11.47, 11.74, and 11.85 x 10(6) kilometers were captured at Jupiter perihelion, whereas Jupiter VIII, IX, XI, and XII in retrograde orbits of 23.5, 23.7, 22.5, and 21.2 x 10(6) kilometers were captured when Jupiter was at aphelion. Examination of the precapture orbits indicates that the seven outer satellites were derived from the asteroid belt.

  14. A 'Moving' Jupiter Global Map (Animation)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    condenses to form the plume tails, and with falling air in the dark areas just to the east of each plume.

    The maps of Jupiter shown here do not include the polar regions, because those regions are not well seen by LORRI from its vantage point high above Jupiter's equatorial region. Shadows of Jupiter's moons (first of Io, then of Ganymede) appear in two of the maps. Name Dates Range from Jupiter [million km]

    Image resolution element [km] JobsATM1 Jan 8-9, 2007 81.2 402 JobsATM2 Jan 9-10, 2007 79.9 396 JobsATM3 Jan 14-15, 2007 71.9 356 JobsATM4 Jan 15, 2007 70.5 349 JobsATM5 Jan 20-21, 2007 61.8 306 JobsATM6 Jan 21-22, 2007 60.5 300

  15. New techniques in astrodynamics for moon systems exploration

    NASA Astrophysics Data System (ADS)

    Campagnola, Stefano

    ESA and NASA scientific missions to the Jupiter and Saturn systems will answer fundamental questions on the habitability of icy worlds. The missions include unprecedented challenges, as the spacecraft will be placed in closed, stable orbits near the surface of the moons. This thesis presents methods to design trajectories that tour the moons and ultimately insert the spacecraft into orbits around them, while mitigating the mission costs and/or risks. A first technique is the endgame, a sequence of moon flyby preceding the orbit insertion. Historically, the endgame is designed with two approaches with different results: the vinfinity-leveraging transfer (VILT) approach leads to high-Deltav (hundreds of m/s), short time-of-flight (months) endgames, while the multi-body approach leads to low-Deltav (tens of m/s), long time-of-flight (years) endgames. This work analyzes and develops both approaches. We introduce a fast design method to automatically compute VILT endgames, which were previously designed in an ad-hoc manner. We also derive an important simple quadrature formula for the minimum Deltav attainable with this approach. This formula is the first important result of this work, as it provides a lower bound for assessment studies. We explain and develop the complex multi-body approach introducing the Tisserand-Poincare (T-P) graph, which is the second important result of this work. It provides a link between the two approaches, and shows the intersections between low-energy trajectories around different moons. With the T-P graph we design a five-month transfer between low-altitude orbits at Europa and Ganymede, using almost half the Deltav of the Hohmann transfer. We then focus on missions to low-mass moons, like Enceladus. We show that nontangent VILT (an extension of the traditional VILT) significantly reduce the Deltav while maintaining a satisfactory transfer time (< 4 years in the Saturn system). With a new design method we compute a 52 gravity

  16. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  17. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J. R.

    2005-01-01

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter.

  18. Is Amalthea a Captured Trojan Asteroid of Jupiter?

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J.

    In 2002 the Galileo spacecraft discovered that the small irregular Jovian moon Amalthea is a porous assemblage of rock and ice. Its bulk density is ~1 g/cc. This is much less than the value ~3.8 g/cc expected of the mixture of rock and metal that would condense at its distance from Jupiter had Amalthea formed from a gas ring shed by the proto-Jovian cloud (Prentice 2001 Earth Moon Planets 87 11). Thus rather than being a native moon of Jupiter (and especially because of its small size relative to the Galilean satellites) Amalthea is probably a captured asteroid. Prentice and ter Haar (1979 Nature 280 300) had predicted Amalthea to be a C-type asteroid. Galileo has found Amalthea to be even less dense than the porous main-belt C-asteroid Mathilde so suggesting the presence of some ice. Most likely therefore Amalthea originally condensed as a planetesimal from the gas ring shed by the proto-Solar cloud at the orbit of Jupiter. The predicted bulk chemical composition by mass is asteroidal rock (65%) graphite (1%) and water ice (34%) [see Prentice 2001 in URL: www.lpi.usra.edu/meetings/mercury01]. The zero-porosity density is 1.8 g/cc. Amalthea is simply a first cousin of the Trojan asteroids of Jupiter

  19. ICI optical data storage tape

    NASA Technical Reports Server (NTRS)

    Mclean, Robert A.; Duffy, Joseph F.

    1991-01-01

    Optical data storage tape is now a commercial reality. The world's first successful development of a digital optical tape system is complete. This is based on the Creo 1003 optical tape recorder with ICI 1012 write-once optical tape media. Several other optical tape drive development programs are underway, including one using the IBM 3480 style cartridge at LaserTape Systems. In order to understand the significance and potential of this step change in recording technology, it is useful to review the historical progress of optical storage. This has been slow to encroach on magnetic storage, and has not made any serious dent on the world's mountains of paper and microfilm. Some of the reasons for this are the long time needed for applications developers, systems integrators, and end users to take advantage of the potential storage capacity; access time and data transfer rate have traditionally been too slow for high-performance applications; and optical disk media has been expensive compared with magnetic tape. ICI's strategy in response to these concerns was to concentrate its efforts on flexible optical media; in particular optical tape. The manufacturing achievements, media characteristics, and media lifetime of optical media are discussed.

  20. The New Moon

    NASA Astrophysics Data System (ADS)

    Crotts, Arlin

    2014-10-01

    Preface; 1. The importance of the Moon; 2. First steps; 3. Moon/Mars; 4. An international flotilla; 5. Moon rise from the ashes; 6. Moons past; 7. The pull of the far side; 8. False seas, real seas; 9. Inconstant Moon; 10. Moonlighting; 11. Lunar living room; 12. Lunar power; 13. Stepping stone; 14. Return to Earth; Index.

  1. Experimental constraints on the chemical evolution of icy satellites

    SciTech Connect

    Scott, H P; Williams, Q; Ryerson, F J

    2000-01-18

    The inferred internal structure of large icy satellites hinges on the degree to which their rock component has been hydrated: this is due to the low density of hydrated silicates relative to anhydrous silicates. Accordingly, interior models of icy satellites have varied greatly in their estimates of ice thickness due to uncertainties in the density of the underlying rock. Furthermore, as both H{sub 2}O (potentially liquid) and organic materials are likely to be present, icy moons have been postulated to be possible hosts for extraterrestrial life; therefore, the stability of organic material under relevant hydrothermal conditions is an important issue. For example, Ganymede, Titan, and Triton are similar in that high pressure hydrothermal processing of silicates has likely been important in their chemical evolution. With mean densities between 1.8 and 2.1 g/cm{sup 3}, compositional models of these bodies incorporate approximately 50--80% silicate minerals by weight, with ices constituting the remaining mass. Moment of inertia constraints on the internal structure of Ganymede demonstrate that differentiation between rock and ice has occurred: such differentiation has also likely occurred in Titan and Triton. During accretion and differentiation (which could be ongoing), the silicate fraction of their interiors would have interacted with aqueous fluids at moderate to high temperatures and pressures. Indeed, a strong magnetic field appears to be generated by Ganymede implying that interior temperatures are high enough (in excess of 1,000 K) to maintain a liquid iron alloy in this satellite. High temperature/pressure hydrothermal processing at rock-water interfaces would profoundly influence the bulk mineralogy and internal structure of these bodies: the degree of hydration of the rocky fraction of these bodies has been a source of ongoing uncertainty. Surprisingly few phase equilibria data exist for compositions of relevance to hydrothermal interactions on icy

  2. Lonely Moon

    NASA Image and Video Library

    2016-10-17

    Pandora is seen here, in isolation beside Saturn's kinked and constantly changing F ring. Pandora (near upper right) is 50 miles (81 kilometers) wide. The moon has an elongated, potato-like shape (see PIA07632). Two faint ringlets are visible within the Encke Gap, near lower left. The gap is about 202 miles (325 kilometers) wide. The much narrower Keeler Gap, which lies outside the Encke Gap, is maintained by the diminutive moon Daphnis (not seen here). This view looks toward the sunlit side of the rings from about 23 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 12, 2016. The view was acquired at a distance of approximately 907,000 miles (1.46 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 113 degrees. Image scale is 6 miles (9 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20504

  3. Moon - 18 Image Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This mosaic picture of the Moon was compiled from 18 images taken with a green filter by Galileo's imaging system during the spacecraft's flyby on December 7, 1992, some 11 hours before its Earth flyby at 1509 UTC (7:09 a.m. Pacific Standard Time) December 8. The north polar region is near the top part of the mosaic, which also shows Mare Imbrium, the dark area on the left; Mare Serenitatis at center; and Mare Crisium, the circular dark area to the right. Bright crater rim and ray deposits are from Copernicus, an impact crater 96 kilometers (60 miles) in diameter. Computer processing has exaggerated the brightness of poorly illuminated features near the day/night terminator in the polar regions, giving a false impression of high reflectivity there. The digital image processing was done by DLR the German aerospace research establishment near Munich, an international collaborator in the Galileo mission. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

  4. A numerical study on collisions of icy bodies using SPH method combined with GRAPE

    NASA Astrophysics Data System (ADS)

    Nakajima, M.; Genda, H.; Ida, S.

    2009-12-01

    We have worked on the collisions of icy bodies using Smoothed Particles Hydrodynamics (SPH) method combined with Gravity PipE (GRAPE) in order to understand the basic behavior of icy bodies during impacts. Collisions of Mars-size rocky bodies have been investigated well, because those collisions are related to the origin of the moon and the formation of the terrestrial planets. On the other hand, collisions of icy bodies have not been studied yet, although these collisions would frequently occur in the solar and extra-solar systems, such as the formation of icy exoplanets. Through our research, we figure out the effect of ice during impact in detail. Our SPH code has two special features. First, GRAvity PipE computer (GRAPE) is used, which calculates the gravitational force of each particle up to 100 times faster than usual computers. Second, SESAME equation of state database is used to build a realistic model, taking into account the effect of phase change. In this research, we focused on differences and similarities between collisions of icy bodies and those of rocky ones, such as a merging criterion. Agnor & Asphaug (2004) have shown that a collision of rocky Mars-size protoplanets leads to an inelastic collision when its relative velocities are smaller than 1.4-1.5v, 1.1-1.2v, 1.1-1.2v when its impact angles are 30, 45, and 60 degrees, respectively. Here, v means escape velocity. The same calculations for icy bodies are performed in our numerical code. They have shown that the merging criterion of icy bodies is the same as that of rocky bodies. In addition to the merging criterion, we also clarify the relationship between impact parameters and the change of solid, liquid/vapor mass ratio due to impacts.

  5. Moon - North Polar Mosaic, Color

    NASA Technical Reports Server (NTRS)

    1996-01-01

    During its flight, the Galileo spacecraft returned images of the Moon. The Galileo spacecraft surveyed the Moon on December 7, 1992, on its way to explore the Jupiter system in 1995-1997. The left part of this north pole view is visible from Earth. This color picture is a mosaic assembled from 18 images taken by Galileo's imaging system through a green filter. The left part of this picture shows the dark, lava-filled Mare Imbrium (upper left); Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is seen at the center of the image. The Moon's north pole is located just inside the shadow zone, about a third of the way from the top left of the illuminated region. The Galileo project is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

  6. Global Moon Coverage via Hyperbolic Flybys

    NASA Technical Reports Server (NTRS)

    Buffington, Brent; Strange, Nathan; Campagnola, Stefano

    2012-01-01

    The scientific desire for global coverage of moons such as Jupiter's Galilean moons or Saturn's Titan has invariably led to the design of orbiter missions. These orbiter missions require a large amount of propellant needed to insert into orbit around such small bodies, and for a given launch vehicle, the additional propellant mass takes away from mass that could otherwise be used for scientific instrumentation on a multiple flyby-only mission. This paper will present methods--expanding upon techniques developed for the design of the Cassini prime and extended missions--to obtain near global moon coverage through multiple flybys. Furthermore we will show with proper instrument suite selection, a flyby-only mission can provide science return similar (and in some cases greater) to that of an orbiter mission.

  7. Evolution of the Moon

    NASA Image and Video Library

    From year to year, the moon never seems to change. Craters and other formations appear to be permanent now, but the moon didn't always look like this. Learn about how the moon evolved from its earl...

  8. A HOT GAP AROUND JUPITER'S ORBIT IN THE SOLAR NEBULA

    SciTech Connect

    Turner, N. J.; Choukroun, M.; Castillo-Rogez, J.; Bryden, G.

    2012-04-01

    The Sun was an order of magnitude more luminous during the first few hundred thousand years of its existence, due in part to the gravitational energy released by material accreting from the solar nebula. If Jupiter was already near its present mass, the planet's tides opened an optically thin gap in the nebula. Using Monte Carlo radiative transfer calculations, we show that sunlight absorbed by the nebula and re-radiated into the gap raised temperatures well above the sublimation threshold for water ice, with potentially drastic consequences for the icy bodies in Jupiter's feeding zone. Bodies up to a meter in size were vaporized within a single orbit if the planet was near its present location during this early epoch. Dust particles lost their ice mantles, and planetesimals were partially to fully devolatilized, depending on their size. Scenarios in which Jupiter formed promptly, such as those involving a gravitational instability of the massive early nebula, must cope with the high temperatures. Enriching Jupiter in the noble gases through delivery trapped in clathrate hydrates will be more difficult, but might be achieved by either forming the planet much farther from the star or capturing planetesimals at later epochs. The hot gap resulting from an early origin for Jupiter also would affect the surface compositions of any primordial Trojan asteroids.

  9. Recent Simulations of the Late Stages Growth of Jupiter

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; D'Angelo, Gennaro; Hubickyj, Olenka

    2012-01-01

    Presented by Lissauer et al. (2009, Icarus 199, 338) are used to test the model of capture of Jupiter's irregular satellites within proto-Jupiter's distended and thermally-supported envelope. We find such capture highly unlikely, since the envelope shrinks too slowly for a large number of moons to be retained, and many of those that would be retained would orbit closer to the planet than do the observed Jovian irregulars. Our calculations do not address (and therefore do not exclude) the possibility that the irregular satellites were captured as a result of gas drag within a circumjovian disk. Support for this research from NASA Outer Planets Research Program is gratefully acknowledged.

  10. Radiation belts of Jupiter - A second look. [Pioneer 11 flyby

    NASA Technical Reports Server (NTRS)

    Fillius, R. W.; Mcilwain, C. E.; Mogro-Campero, A.

    1975-01-01

    The outbound leg of the Pioneer 11 Jupiter flyby explored a region farther from the equator than that traversed by Pioneer 10, and the new data require modification or augmentation of the magnetodisk model based on the Pioneer 10 flyby. The inner moons of Jupiter are sinks of energetic particles and sometimes sources. A large spike of particles was found near Io. Multiple peaks occurred in the particle fluxes near closest approach to the planet; this structure may be accounted for by a complex magnetic field configuration. The decrease in proton flux observed near minimum altitude on the Pioneer 10 flyby appears attributable to particle absorption by Amalthea.

  11. Jupiter Orbiter and Probe project - Synthesis of the mission design

    NASA Technical Reports Server (NTRS)

    Beckman, J. C.; Roberts, P. H., Jr.

    1977-01-01

    The Jupiter Orbiter Probe (JOP), scheduled to be launched by the Shuttle IUS in 1981, is described in terms of its scientific mission objectives. These include: analysis of the chemical composition and physical state of Jupiter's atmosphere, the chemical composition and physical state of Ganymede and Callisto, and the topology and behavior of the magnetic field and energetic particle fluxes. Attention is given to an atmospheric probe which will be launched from the main probe, and to the navigation requirements necessary to 'bounce' the JOP around the Jovian moons.

  12. Origin and evolution of the earth-moon system.

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Arrhenius, G.

    1972-01-01

    The general problem of formation of secondary bodies around a central body is studied, and comparison is made with other satellite systems (Jupiter, Saturn, Uranus). The normal satellite systems of Neptune and the earth are reconstructed. The capture theory, the tidal evolution of the lunar orbit, destruction of a normal satellite system, asteroids and the earth-moon system, and accretion and heat structure of the moon are discussed. It is concluded that the moon originated as a planet accreted in a jet stream near the orbit of the earth, and was probably captured in a retrograde orbit.

  13. Medicean Moons Sailing Through Plasma Seas: Challenges in Establishing Magnetic Properties

    NASA Astrophysics Data System (ADS)

    Kivelson, Margaret G.; Jia, Xianzhe; Khurana, Krishan K.

    2010-01-01

    Jupiter's moons, embedded in the magnetized, flowing plasma of Jupiter's magnetosphere, the plasma seas of the title, are fluids whose highly non-linear interactions imply complex behavior. In a plasma, magnetic fields couple widely separated regions; consequently plasma interactions are exceptionally sensitive to boundary conditions (often ill-specified). Perturbation fields arising from plasma currents greatly limit our ability to establish more than the dominant internal magnetic field of a moon. With a focus on Ganymede and a nod to Io, this paper discusses the complexity of plasma-moon interactions, explains how computer simulations have helped characterize the system and presents improved fits to Ganymede's internal field.

  14. The Edge of Jupiter

    NASA Image and Video Library

    2017-04-19

    This enhanced color Jupiter image, taken by the JunoCam imager on NASA's Juno spacecraft, showcases several interesting features on the apparent edge (limb) of the planet. Prior to Juno's fifth flyby over Jupiter's mysterious cloud to