DOCSLIB.ORG

EJSM-Laplace Why Are Ganymede and Europa Habitable Worlds ?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
EJSM-Laplace Why Are Ganymede and Europa Habitable Worlds ? Exploring icy satellites for their Astrobiological potential from an astronomical point of view Athena Coustenis LESIA, Paris-Meudon Observatory France Galileo Cassini-Huygens Quelques points de considération Aspects astrobiologiques: chimie organique, eau liquide (en surface ou à l’intérieur), sources d’énergie (activité interne), stabilité Les satellites de glace avec organiques : Titan, Encelade, Triton. avec une activité évidente : Encelade, Triton, Io, (Titan?) avec de l’eau liquide à l’intérieur (à confirmer): Europe, Ganymède, Encelade, Titan A l’exception de Titan, les satellites de glace avec des océans subsurfaciques possibles (Europe, Ganymède, Callisto) ou une activité cryovolcanique évidente (Encelade, Triton) résident à l’intérieur des magnétosphères des planètes géantes, mais les deux derniers ne sont pas dans la partie avec l’irradiation surfacique extrême et destructive pour les organiques. Quel est le potentiel astrobiologique de chacun de ces satellites? Exploring the Habitability of Icy Worlds: The Europa Jupiter System Mission (JUICE) The EJSM Science Study Team 2009 All rights reserved. EJSM Theme: The Emergence of Habitable Worlds Around Gas Giants • Goal 1: Determine if the Jupiter system harbors habitable worlds • Goal 2: Characterize Jupiter system processes – Ocean characteristics (for Europa and Ganymede and perhaps other satellites) – Satellite system – Ice shells and subsurface water – Jupiter atmosphere – Deep internal structure, and (for – Magnetodisk/magnetosphere Ganymede) intrinsic magnetic field – Jovian system Interactions – External environments – Jovian system origin – Global surface compositions – Surface features and future landing sites Emphasis on icy moon habitability and Jupiter system processes 5 JGO Science: Overview • Key JGO science phases – Ganymede: Detailed orbital study . Elliptical orbit first, then circular orbit – Jupiter system: In-depth exploration . From Jupiter orbit, synergistically with JEO – Callisto: In-depth study and mapping . Multiple flybys using a resonant orbit • Science Objectives: – Ganymede: Characterize Ganymede as a planetary object, including its potential habitability – Satellite System: Study the Jovian satellite system – Jupiter: Study the Jovian atmosphere – Magnetosphere: Study the Jovian magnetodisk / magnetosphere – Jupiter system: Study the interactions occurring in the Jovian system 6 Ganymede studies with JUICE Tidal deformation Geology and Topography • Presence and extent of a subsurface ocean • Ice shell and subsurface water • Deep internal structure, dynamo, magnetic field • Coupling among surface, exosphere, Deep Interior and Magnetic Field and magnetosphere • Surface composition and chemistry • Surface features, tectonic processes • Thermal evolution, geology, and the Magnetosphere and Laplace resonance Environment Structure and topography of Mars' Polar Cap Compositional Differences 7 1. Why is Ganymede an habitable world Theme 2: Habitability of the icy moons EJSM-Laplace Why are Ganymede and Europa habitable worlds ? Liquid water The habitable zone is not restricted to the Earth’s orbit… Stable environment Essential elements Energy Surface habitats Deep habitats Deep habitats Europa: Ocean • Ice • Chemistry • Geology Determine global surface compositions and chemistry, especially as related to habitability Composition is key to understanding ocean habitability 9 Europa: Ocean • Ice • Chemistry • Geology Global surface composition & chemistry: • Organic & inorganic chemistry • Relation to geologic processes • Radiation effects • Exogenic materials Composition is key to understanding Europa’s habitability 6/29/2011 10 Europa: Ocean • Ice • Chemistry • Geology Understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ exploration mosaic by Orion 11 Europa: “Ingredients” for Life? e-, O+, S+, … • Water: – Warm salty H2O ocean. radiation-produced oxidants: O2, H2O2, CH2O • Essential elements: – Accretion of CO2? – Impactors. – But radiation destroys organics in upper ~10s cm of ice. • Chemical energy: – Radiation of H2O ⇒ oxidants. – Mantle contact: serpentinization and possible hydrothermal activity. • Relatively stable environment: hydrothermally produced reductants: H2S, H2, CH4, Fe – Large satellite retains heat. – But activity might not be steady-state. [after Stevenson, 2000] Europa: Ocean • Ice • Chemistry • Geology Ice shell & subsurface water: • Shallow water • Ice-ocean interface • Material exchange • Heat flow variations SHARAD, Mars north polar cap [Seu, Phillips, and the SHARAD team] Radar sounding can characterize the ice shell 6/29/2011 8 Liquid water Theme 2: Habitability of the icy moons LIQUID WATER EJSM-Laplace Galileo evidence of liquid layers Geologic activity Induced magnetic field Production of a ±3˚ tilt of internal dipole moment over a 10 hour period. marginally demonstrated but more data needed Credits: Kivelson Thermal modelling Science questions - Existence of the liquid layer - Spatial distribution - Relationship with geology/surface - Physical characteristics Credits: Bland Liquid water Theme 2: Habitability of the icy moons LIQUID WATER EJSM-Laplace Ganymede’s ocean: what EJSM-Laplace will do… Induced magnetic field at multiple frequencies Magnetometer Radio and Plasma Waves Tidal deformation of the surface Radio science laser altimetry MR and HR imaging Libration amplitudes Radio science laser altimetry Hydrostatic equilibrium Radio science laser altimetry Jupiter System ~2.5 y Elliptical Circular 500 Circular 200 15 moon flybys 40 days 80 days 60 days Liquid water Theme 2: Habitability of the icy moons ESSENTIAL ELEMENTS EJSM-Laplace Galileo evidences for an outstanding complexity Complex chemistry Complex dynamics Credits: Khurana Specific albedo distribution Brines and Alteration on open field lines hydrates are good candidates Water ice abundance – NIMS data Science questions • What are the non–water ice chemical compounds ? • What is the endogeneous and the exogeneous repartition of this surface material ? • What is the effect of radiation weathering on these materials ? • How can we correlate the surface compounds with the sub-surface composition ? Essential elements Theme 2: Habitability of the icy moons ESSENTIAL ELEMENTS EJSM-Laplace Surface composition of the moons: what EJSM-Laplace will do… What are the surface chemical compounds ? Exogeneous versus endogeneous ? Volatiles Near-IR imaging spectrometer Ion and Neutral mass spectrometry • Major volatiles UV imaging spectrometer Particles and plasma instrument • Stable isotopes C,H,O • Noble gases Ar, Kr, Xe • Mapping of oxygen species Ions and Neutrals • Identification • Surface 2D distribution How does the surface relate to the subsurface ? Subsurface radar sounding Spatial coverage Sub-mm wave sounding • > 80 % at a few km/pxl • X 100 m/pxl on a few % • X10 m/pxl if needed MARSIS: South Polar Deposits Spectral coverage • > 5 times better at regional scale • Lab data quality when needed Global scale Regional / Local scales Jupiter System ~2.5 y Elliptical Circular 500 Circular 200 15 moon flybys 40 days 80 days 60 days Energy-Galileo Theme 2: Habitability of the icy moons ENERGY EJSM-Laplace What are the energy sources? External sources Internal sources Impactors Particles Tidal Radiogenic Secular ? Science questions - What is the evolution of the impactor population in the Jovian system through time? - What is the amount of heat that is expelled through the surface of the moons? - How much tidal heating is distributed within the moons? Enceladus E-ring source Old Faithful by Starlight (Credit: Tyler Nordgren) Hidden Energy Sources ? Radiolytic Chemistry vs Solar & Tidal Heating ? Triton cryovolcanism (dark streaks) Energy Fluxes mW/m2 Mimas 2.5 Enceladus 0.73 Tethys 0.48 Dione 0.44 Rhea 0.29 Callisto 0.19 Ganymede 5.4 Europa 99 Triton ~ 5 Cooper et al., PSS, 2009 Energy - external sources Theme 2: Habitability of the icy moons ENERGY EJSM-Laplace How much energy remains from the early stages ? Impact cratering Surface heat flux Ganymede possesses the widest range in crater morphology Thermal IR mapper Low and High resolution imaging Subsurface radar sounding Vis-IR spectro imaging Sub-mm wave instrument Sub-surface radar sounding Credits: Schenk Distribution: Nearly global coverage at 200-400 m/px resolutions + HR target areas (5-50 m/px) Present activity: monitoring on a timescale x 100 days up to years to identify potentially newly formed craters Buto Facula Jupiter System ~2.5 y Elliptical Circular 500 Circular 200 15 moon flybys 40 days 80 days 60 days Energy - internal sources Theme 2: Habitability of the icy moons ENERGY EJSM-Laplace How much heat is available in the interior of the moons ? Intrinsic magnetic field Magnetometer Radio and Plasma Waves Constraints on the core size and dynamics Gravitational field Radio science Laser altimetry Equilibrium state Averaged density profiles Mass anomalies determination Tidal deformation Radio science Laser altimetry MR and HR imaging Equilibrium state Jupiter System ~2.5 y Elliptical Circular 500 Circular 200 15 moon flybys 40 days 80 days 60 days Stability - Galileo Theme 2: Habitability of the icy moons STABILITY EJSM-Laplace How stable are the present states? Geology as a witness of moon’s evolution Stability of the system Science questions -What do geologic features tell us about the past and present internal activity ? -How did the habitable zone evolve through time ? Stability - resonnance
Load more

Recommended publications
  • Mission to Jupiter
    This book attempts to convey the creativity, Project A History of the Galileo Jupiter: To Mission The Galileo mission to Jupiter explored leadership, and vision that were necessary for the an exciting new frontier, had a major impact mission’s success. It is a book about dedicated people on planetary science, and provided invaluable and their scientific and engineering achievements. lessons for the design of spacecraft. This The Galileo mission faced many significant problems. mission amassed so many scientific firsts and Some of the most brilliant accomplishments and key discoveries that it can truly be called one of “work-arounds” of the Galileo staff occurred the most impressive feats of exploration of the precisely when these challenges arose. Throughout 20th century. In the words of John Casani, the the mission, engineers and scientists found ways to original project manager of the mission, “Galileo keep the spacecraft operational from a distance of was a way of demonstrating . just what U.S. nearly half a billion miles, enabling one of the most technology was capable of doing.” An engineer impressive voyages of scientific discovery. on the Galileo team expressed more personal * * * * * sentiments when she said, “I had never been a Michael Meltzer is an environmental part of something with such great scope . To scientist who has been writing about science know that the whole world was watching and and technology for nearly 30 years. His books hoping with us that this would work. We were and articles have investigated topics that include doing something for all mankind.” designing solar houses, preventing pollution in When Galileo lifted off from Kennedy electroplating shops, catching salmon with sonar and Space Center on 18 October 1989, it began an radar, and developing a sensor for examining Space interplanetary voyage that took it to Venus, to Michael Meltzer Michael Shuttle engines.
    [Show full text]
  • Arxiv:2003.06680V2 [Astro-Ph.EP] 1 Apr 2021 Ations in Tidal Forces Alone
    Europa's Hemispheric Color Dichotomy as a Constraint on Non-Synchronous Rotation Ethan R. Burnett∗1 and Paul O. Hayne2,3 1Aerospace Engineering Sciences, University of Colorado Boulder 2Astrophysical and Planetary Sciences, University of Colorado Boulder 3Laboratory for Atmospheric and Space Physics, University of Colorado Boulder Europa's surface reflectance exhibits a pronounced hemispheric dichotomy, which is hypoth- esized to form due to enhanced irradiation of the trailing hemisphere by energetic particles entrained in the jovian magnetosphere. We propose that this pattern can only persist if the timescale for discoloration is much shorter than that of Europa's rotation relative to the syn- chronous state, and provide a means for constraining the rotation rate using the observed color pattern. By decomposing the longitudinal ultraviolet and visible color variations from Voyager data into sine and cosine terms, we find no detectable signature of non-synchronous rotation (NSR). This same conclusion is reached with two observational models of discoloration: one representing an actively discoloring surface, and the other assuming that the present-day exo- genic discoloration on the surface is in steady-state. Magnitudes of the expected signature are presented as functions of the age of the crater Pwyll, which is used to constrain the timescale of discoloration. Furthermore, we develop a physical model of discoloration to validate the ge- ometric models, producing consistent results. The failure to identify a signature of NSR using Europa's hemispheric color dichotomy magnifies the outstanding problem of the origin of the stress to explain Europa's pervasive tectonic features. 1 Introduction and Background The present-day icy surface of Europa is covered with large ridges and cracks, which are generally the result of tidal stresses during Europa's eccentric 3.55-day orbit about Jupiter.
    [Show full text]
  • Uncorrected Proof
    Planetary and Space Science xxx (xxxx) xxx-xxx Contents lists available at ScienceDirect Planetary and Space Science journal homepage: http://ees.elsevier.com Joint Europa Mission (JEM) a multi-scale study of Europa to characterize its habitability and search for extant life Michel Blanc a,∗, Nicolas André a, Olga Prieto-Ballesteros b, Javier Gomez-Elvira b, Geraint Jones c, Veerle Sterken d,e, William Desprats a,f, Leonid I. Gurvits g,p,ak, Krishan Khurana h, Aljona Blöcker i, Renaud Broquet j, Emma Bunce k, Cyril Cavel j, Gaël Choblet l, Geoffrey Colins m, Marcello Coradini n, John Cooper o, Dominic Dirkx p, Philippe Garnier a, David Gaudin f, Paul Hartogh q, Luciano Iess r, Adrian Jäggi d, Sascha Kempf s, Norbert Krupp q, Luisa Lara t, Jérémie LasuePROOFa, Valéry Lainey u, François Leblanc v, Jean-Pierre Lebreton w, Andrea Longobardo x, Ralph Lorenz y, Philippe Martins z, Zita Martins aa, Adam Masters ab,al, David Mimoun f, Ernesto Palumba x, Pascal Regnier j, Joachim Saur ac, Adriaan Schutte ad, Edward C. Sittler o, Tilman Spohn ae, Katrin Stephan ae, Károly Szegő af, Federico Tosi x, Steve Vance ag, Roland Wagner ae, Tim Van Hoolst ah, Martin Volwerk ai, Frances Westall aj a IRAP, France b INTA-CAB, Spain c MSSL/UCL, UK d University of Bern, Switzerland e ETH Zürich, Switzerland f ISAE, France g Joint Institute for VLBI ERIC, Dwingeloo, the Netherlands h UCLA, USA i Royal Institute of Technology KTH, Sweden j Airbus D&S, France k Univ. Leicester, UK l LPG, Univ. Nantes, France mWheaton College, USA n CSEO, USA o GSFC, USA p TU Delft, the Netherlands q MPS, Germany r Univ.
    [Show full text]
  • Endogenic and Exogenic Contributions to Visible-Wavelength Spectra of Europa’S Trailing Hemisphere
    Preprint typeset using LATEX style AASTeX6 v. 1.0 ENDOGENIC AND EXOGENIC CONTRIBUTIONS TO VISIBLE-WAVELENGTH SPECTRA OF EUROPA'S TRAILING HEMISPHERE Samantha K. Trumbo, Michael E. Brown Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA Kevin P. Hand Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA ABSTRACT The composition of Europa's trailing hemisphere reflects the combined influences of endogenous geo- logic resurfacing and exogenous sulfur radiolysis. Using spatially resolved visible-wavelength spectra of Europa obtained with the Hubble Space Telescope, we map multiple spectral features across the trailing hemisphere and compare their geographies with the distributions of large-scale geology, mag- netospheric bombardment, and surface color. Based on such comparisons, we interpret some aspects of our spectra as indicative of purely exogenous sulfur radiolysis products and other aspects as in- dicative of radiolysis products formed from a mixture of endogenous material and magnetospheric sulfur. The spatial distributions of two of the absorptions seen in our spectra|a widespread down- turn toward the near-UV and a distinct feature at 530 nm|appear consistent with sulfur allotropes previously suggested from ground-based spectrophotometry. However, the geographies of two addi- tional features|an absorption feature at 360 nm and the spectral slope at red wavelengths|are more consistent with endogenous material that has been altered by sulfur radiolysis. We suggest irradiated sulfate salts as potential candidates for this material, but we are unable to identify particular species with the available data. Keywords: planets and satellites: composition | planets and satellites: individual (Europa) | planets and satellites: surfaces 1.
    [Show full text]
  • Galileo Reveals Best-Yet Europa Close-Ups Stone Projects A
    II Stone projects a prom1s1ng• • future for Lab By MARK WHALEN Vol. 28, No. 5 March 6, 1998 JPL's future has never been stronger and its Pasadena, California variety of challenges never broader, JPL Director Dr. Edward Stone told Laboratory staff last week in his annual State of the Laboratory address. The Laboratory's transition from an organi­ zation focused on one large, innovative mission Galileo reveals best-yet Europa close-ups a decade to one that delivers several smaller, innovative missions every year "has not been easy, and it won't be in the future," Stone acknowledged. "But if it were easy, we would­ n't be asked to do it. We are asked to do these things because they are hard. That's the reason the nation, and NASA, need a place like JPL. ''That's what attracts and keeps most of us here," he added. "Most of us can work elsewhere, and perhaps earn P49631 more doing so. What keeps us New images taken by JPL's The Conamara Chaos region on Europa, here is the chal­ with cliffs along the edges of high-standing Galileo spacecraft during its clos­ lenge and the ice plates, is shown in the above photo. For est-ever flyby of Jupiter's moon scale, the height of the cliffs and size of the opportunity to do what no one has done before­ Europa were unveiled March 2. indentations are comparable to the famous to search for life elsewhere." Europa holds great fascination cliff face of South Dakota's Mount To help achieve success in its series of pro­ for scientists because of the Rushmore.
    [Show full text]
  • Europa Deep Dive 2: Chemical Composition of Europa and State of Laboratory Data
    Program Europa Deep Dive 2: Chemical Composition of Europa and State of Laboratory Data October 9–11, 2018 • Houston, Texas Institutional Support Lunar and Planetary Institute Universities Space Research Association Conveners Louise M. Prockter USRA/Lunar and Planetary Institute Jonathan Kay USRA/Lunar and Planetary Institute Science Organizing Committee Murthy S. Gudipati NASA Jet Propulsion Laboratory Reggie L. Hudson NASA Goddard Space Flight Center Lynnae C. Quick Smithsonian Institution/Air and Space Museum Abigal M. Rymer Johns Hopkins University/Applied Physics Laboratory Jason M. Soderblom Massachusetts Institute of Technology Lunar and Planetary Institute • 3600 Bay Area Boulevard • Houston TX 77058-1113 Abstracts for this workshop are available via the workshop website at https://www.hou.usra.edu/meetings/europadeepdive2018/ Abstracts can be cited as Author A. B. and Author C. D. (2018) Title of abstract. In Europa Deep Dive 2: Chemical Composition of Europa and State of Laboratory Data, Abstract #XXXX. LPI Contribution No. 2100, Lunar and Planetary Institute, Houston. Guide to Sessions Tuesday, October 9, 2018 8:30 a.m. Great Room Registration 9:30 a.m. Lecture Hall Terrestrial Based Observation 1:20 p.m. Lecture Hall Observations and Lab Work 5:00 p.m. Great Room Europa Deep Dive Poster Session Wednesday, October 10, 2018 9:00 a.m. Lecture Hall Effects of Radiation 12:40 p.m. Lecture Hall Lab Work and Modeling Thursday, October 11, 2018 9:00 a.m. Lecture Hall Lab Work and Analogues Program Tuesday, October 9, 2018 TERRESTRIAL BASED OBSERVATION 9:30 a.m. Lecture Hall Chair: Bryana Henderson 9:30 a.m.
    [Show full text]
  • Intro to Solar System Jovian Planets and Moons 1 Jovian Planets
    Jovian Planets and Moons Intro to Solar System Jovian Planets and Moons 1 Jovian Planets primitive, look much as they did at time of formation gas giants, completely different than the terrestrial planets Intro to Solar System Jovian Planets and Moons 2 Jupiter • largest most massive of all • size 140,00 km 11 Earths across • mass - 300 times Voyager Project, JPL, NASA that of Earth 3 • density 1300 kg/m Intro to Solar System Jovian Planets and Moons 3 Jupiter - Composition hydrogen, helium - liquid and gaseous gases that have been there since formation temperature: 130 K escape speed: 60 km/sec even hydrogen can’t get away! Intro to Solar System Jovian Planets and Moons 4 Jupiter - “Surface” there is NO surface !! convective flow in the atmosphere light regions: zones - tops of high pressure regions dark regions: belts - descending areas of low pressure convective flow tells us the interior is HOT! Intro to Solar System Jovian Planets and Moons 5 Jupiter - “Surface” rotation: 10 hours differential rotation => a fluid cloud speed: 43,00 km/hr Intro to Solar System Jovian Planets and Moons 6 Great Red Spot NASA permanent storm: observed in 1630 cooler than surrounding zone, is raised a few km above it rotates counterclockwise, 7 day period Intro to Solar System Jovian Planets and Moons 7 Jupiter - Atmosphere 82% Hydrogen 18% Helium ammonia ice crystals, liquid ammonia, water ice Galileo - Probe Entry Point 1000 km thick Intro to Solar System Jovian Planets and Moons 8 Jupiter - Internal Structure • low density and atmospheric composition
    [Show full text]
  • Europa Quad Echo (EQE)
    Europa Quad Echo (EQE) Sub-cryospheric investigation into the habitability of Europa Editors: - Kolja Hanke - Micha Nebel - Benjamin Heikki Redmond Roche December 2017 Contents Page Chapter 1 - Introduction To The Exploration Of Europa (Page 2) Chapter 2 - The Structure Of Europa (Page 3) Chapter 3 - The Required Parameters For Life (Page 5) Chapter 4 - The Zones Of Europa (Page 8) Chapter 5 - Indicators For Life (Page 10) 5.1 - Indicators of Astrobiology & Instrumentation (Page 10) 5.2 - Sensitivity of Instruments (Page 12) 5.3 - Amino-Acids as potential Indicator of Life (Page 13) 5.4 - Sterilisation (Page 15) Chapter 6 - Target Zones For Exploration (Page 17) 6.1 - Cryogenic Morphology Of Europa (Page 17) 6.2 - Target Zones Of Europa (Page 24) Chapter 7 - Discussion & Mission Options (Page 29) Chapter 8 - Reference List (Page 33) 1 December 2017 1. Introduction On the 8th of January 1610, Galileo Galilei pointed his telescope at Jupiter and made a ground- breaking discovery; changing humanity’s perspective of the Earth, the universe and its own place within it. He had discovered the four moons of Jupiter: Io, Ganymede, Callisto and Europa. In the following few centuries Europa, the smallest Galilean moon, was disregarded until exploration occurred in the 1970s with the Pioneer (10 & 11) and Voyager (1 & 2) flybys; and subsequently the Galileo Mission (1995-2003), which undertook detailed analyses of the Galilean network for the first time. The data collected by these missions revealed the Europan surface consists of water ice and seems to be very young, according to the small number of visible craters (Carlson et al., 2009).
    [Show full text]
  • Europa Robert Pappalardo Laboratory for Atmospheric and Space Physics and the NASA Astrobiology Institute University of Colorado at Boulder Europa's Ocean: Overview
    Europa Robert Pappalardo Laboratory for Atmospheric and Space Physics and the NASA Astrobiology Institute University of Colorado at Boulder Europa's Ocean: Overview • What is the evidence for an ocean within Europa? • Is Europa active today, and has activity changed through time? • What are Europa’s sources of free energy and biogenic elements? • How might the interior and surface of Europa communicate? Geology of Europa: Overview • Interior constraints: Gravity Magnetometry • Geology: Stress mechanisms Ridge origin(s) Bands Lenticulae & convection Chaos Surface composition Impact structures Changes through time • The future: JIMO Europa's Interior: Gravity Data Axial moment of inertia from Doppler gravity data: Ic = 0.346 ± 0.005 H2O-rich crust: ~80 - 170 km thick. [Anderson et al., 1998] Europa's Bimodal Geology ridged plains mottled terrain Europa's Eccentric Orbit 85 hr orbit • Eccentric orbit (e = 0.01). • Solid body tide ~30 m if ice shell is decoupled by ocean. • Libration (constant rotation rate; variable orbital speed). • Complexly varying diurnal stress field with maximum stress ~0.1 MPa. • Tidal bulge torque promotes nonsynchronous rotation. • Deformation dissipates energy: tidal heating. torque min. not to scale potential min. Nonsynchronous Rotation Stress • Nonsynchronous rotation stress pattern backrotated ~25° provides the best match to global lineament patterns. • Nonsynchronous rotation is facilitated if ice shell is decoupled from rocky mantle. Suggests decoupling by global ocean. • Stresses ~0.1 MPa per degree of shell rotation. Nonsynchronous Rotation Stress • Assume brittle failure perpendicular to tensile stress ticks. Compression Tension Compression Tension 0.5 MPa Arcuate Cracks from Nonsynchronous Rotation Stress Compression Tension Compression Tension Global Lineament Fit to 25° Backrotated NSR (backrotated west 25°) "Diurnal" Stresses Compression Tension Cycloidal Fracture Form from Diurnal Stress Tension Tension Cycloidal Ridges • Cycloids explained by time-varying diurnal stresses.
    [Show full text]
  • Science from the Jupiter Europa Orbiter—A Future Outer Planet Flagship Mission
    Exploring Europa: Science from the Jupiter Europa Orbiter—A Future Outer Planet Flagship Mission Louise M. Prockter, Kenneth E. Hibbard, Thomas J. Magner, and John D. Boldt he Europa Jupiter System Mission, an international joint mission recently studied by NASA and the European Space Agency, would directly address the origin and evolution of satellite systems and the water-rich environ- ments of icy moons. In this article, we report on the scientific goals of the NASA-led part of the Europa Jupiter System Mission, the Jupiter Europa Orbiter, which would investigate the potential habitability of the ocean-bearing moon Europa by character- izing the geophysical, compositional, geological, and external processes that affect this icy world. INTRODUCTION About 400 years ago Galileo Galilei discovered the continued in 1994 with the arrival of the Galileo space- four large moons of Jupiter, thereby spurring the Coper- craft. After dropping a probe into Jupiter’s atmosphere, nican Revolution and forever changing our understand- the spacecraft spent several years orbiting the giant ing of the universe. Today, these Galilean satellites planet, accomplishing flybys of all the Galilean satellites, may hold the key to understanding the habitability of Io, Europa, Ganymede, and Callisto. Despite significant icy worlds, as three of the moons are believed to harbor technical setbacks, including the loss of the main com- internal oceans. On Earth, water is the key ingredient munication antenna and issues with the onboard tape for life, so it is reasonable that the search for life in our recorder, the spacecraft returned valuable data that sig- solar system should focus on the search for water.
    [Show full text]
  • Joint Europa Mission (JEM) a Multi-Scale Study of Europa
    Joint Europa Mission (JEM) a multi-scale study of Europa to characterize its habitability and search for extant life Michel Blanc, Nicolas André, Olga Prieto-Ballesteros, Javier Gómez-Elvira, Geraint Jones, Veerle Sterken, William Desprats, Leonid Gurvits, Krishan Khurana, Aljona Blöcker, et al. To cite this version: Michel Blanc, Nicolas André, Olga Prieto-Ballesteros, Javier Gómez-Elvira, Geraint Jones, et al.. Joint Europa Mission (JEM) a multi-scale study of Europa to characterize its habitability and search for extant life. Planetary and Space Science, Elsevier, 2020, 193, pp.104960. 10.1016/j.pss.2020.104960. insu-02883533 HAL Id: insu-02883533 https://hal-insu.archives-ouvertes.fr/insu-02883533 Submitted on 30 Jun 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Journal Pre-proof Joint Europa Mission (JEM) a multi-scale study of Europa to characterize its habitability and search for extant life Michel Blanc, Nicolas André, Olga Prieto-Ballesteros, Javier Gomez-Elvira, Geraint Jones, Veerle Sterken, William Desprats, Leonid I. Gurvits, Krishan Khurana, Aljona Blöcker, Renaud Broquet, Emma Bunce, Cyril Cavel, Gaël Choblet, Geoffrey Colins, Marcello Coradini, John Cooper, Dominic Dirkx, Philippe Garnier, David Gaudin, Paul Hartogh, Luciano Iess, Adrian Jäggi, Sascha Kempf, Norbert Krupp, Luisa Lara, Jérémie Lasue, Valéry Lainey, François Leblanc, Jean-Pierre Lebreton, Andrea Longobardo, Ralph Lorenz, Philippe Martins, Zita Martins, Adam Masters, David Mimoun, Ernesto Palumba, Pascal Regnier, Joachim Saur, Adriaan Schutte, Edward C.
    [Show full text]
  • Polar Lander Heads to Red Planet at 4:03 P.M
    Special issue: 1998 in review / 1999 preview Laboratory Pasadena, California Vol. 29, No. 1 January 8, 1999 Jet Propulsion Universe Polar Lander heads to red planet At 4:03 p.m. EST, Mars Polar Lander separat- By DIANE AINSWORTH ed from the third stage. A set of solar panels locat- After a stellar launch at 3:21 p.m. Eastern ed on the spacecraft’s outer cruise stage were Standard Time on Sunday, Jan. 3, NASA’s Mars deployed shortly thereafter and pointed at the Sun. Polar Lander is now on its way to the south pole of The lander’s signal was acquired at 4:19 p.m. EST Mars to search for water ice beneath the edge of lay- over Canberra, Australia, by a 34-meter-diameter ered terrain in this uncharted region of the planet. (112-foot) Deep Space Network antenna. The spacecraft was launched atop a Delta II- The spacecraft is in excellent health, the class launch vehicle identical to the expendable flight team reports, and continues to show nor- rocket used to loft Mars Climate Orbiter into mal power and temperature levels and the prop- space on Dec. 11, 1998. Hitchhiking aboard the er attitude control for telecommunications with diminutive spacecraft are two grapefruit-sized Earth using its medium-gain horn antenna. microprobes designed to crash into Mars’ surface Earlier in the week, the flight team was con- and carry out up to seven days of soil and water tinuing to analyze data from Mars Polar Lander’s experiments as far as 1 meter (3 feet) below the star camera, which had not yet been able to lock Martian surface.
    [Show full text]