Voyages to Jupiter Galileo & Cassini. Galileo Mission.

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Voyages to Jupiter Galileo & Cassini

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  • Voyages to Jupiter

    Galileo & Cassini

  • Galileo Mission

  • Galileo Spacecraftspins 3 rpm

  • 33 orbits and still going ...

  • Jupiter is a giant ball of hydrogen gas Only outermost layers were probedEarth to scale

  • Probe Entered Downdraft Region Between Clouds

  • Probe Results Probe measured temperature, pressure, wind speed and chemical composition as it descended ~ 100km. Probe detectedOnly tenuous cloudsVery dry airStrong winds >600 km/hr Chemical composition consistent with solar abundance + cometary material

  • White = ammonia cloudsOrange = sulfur-colored ammoniaSmall scale turbulence generated by wind shears coalesce to form large scale vortices. Storms such as the Great Red Spot and white ovals last for decades to centuries.

  • Wind Shear and Eddies

  • Eddies MergingFeb. 1997Sep. 1998Two white ovals formed in 1930sTwo Merged to one oval 60+ years later

  • Jupiters Ring Faint, tenuous rings of small particles chipped off small inner moons.

    Orbits shaped by satellites, evolve rapidly.

  • The Galilean Satellites

  • Galilean Satellite Geology

  • Zooming in on Callistos Craters

  • Chain of craters on CallistoCaused by broken up comets - such as Comet Shoemaker-Levy 9

  • Bright TerrainDark TerrainFewer cratersYoungerGrooved & foldedMany cratersOlderGanymedes Varied Geology

  • Grooves caused by expansion of Ganymedes crust

  • Callisto and Ganymede- Heating of Ganymede led to separation of dense iron core, surrounded by rock with thick layer of ice on top.- Dark dust has accumulated on older surfaces of Callisto and Ganymede, burying small craters - Callisto suffered little heating and remains a mixture of ice and rock

  • EuropaDark Material Seeping Through Cracks

  • Ridges, Spots & Smooth Icy Plains

  • CaliforniaEuropaSan Andreas FaultAstypalaea Linea

  • 50 km10 km5 kmZooming in on Cracks and FlowsIce - sometimes it suddenly cracks, sometimes it slowly flows

  • Europas young surface shows few cratersDid this impactor crash right through the ice?

  • High resolution images show ice rafts - indication of thin ice crust, liquid ocean below?

  • San Fran Scale Comparison

  • The interior is mostly rock covered by a ~150 km layer of water A brittle crust (1-10km thick) has been disrupted in the past 10 million years by underlying fluid motions Does Europa have a liquid ocean? Could such ocean contain life? Or, is the water layer frozen, moving slowly, like a glacier?Europa

  • FrecklesCompeting TheoriesUpwelling PlumesTidal Cracking

  • Io3.57 g/ccGanymede1.94 g/ccEuropa2.97 g/ccCallisto1.86 g/cc

  • Tidal HeatingLaplace orbital ResonanceTidal forces increase strongly closer to JupiterHeat the interiorRemove waterDrive volcanic activity

  • IoAmirani300 km

  • Ios Volcanoes& GeysersIRPilan 5 months apartPrometheusPilan PlumePele

  • After quantities of lava are removed from below, the crust cracks and tilts, making tall, blocky mountains.TvashtarHiiaka Patera50 km11 km high

  • Io Mtns

  • Nightside of Io - VisibleGlowing LavaPlume Gas & Dust + Airglow

  • IoGanymedeEuropaCallisto1 ton / secJupiters Giant Magnetosphere

  • Plasma Production at IoSchneider & TraugerNeutralSodiumIonizedSulfur

  • Io Plasma Torus (Schneider & Trauger)

  • Cassini UltraViolet Imaging SpectrometerLarry Esposito, University of ColoradoUV images of the toroidal cloud of ions at Ios orbit, The S+ and O+ ions are trapped by Jupiters magnetic field. Jupiter is dark at UV wavelengths.

  • Jovian Aurora Radio to X-rays Power into polar atmosphere > solar flux(1) Main oval linked to middle magnetosphere(2) Polar storms(3) Satellite footprints

  • AuroraIo footprintIo wakeMain OvalPolar stormsDusk Distortion?Clarke et al.

  • Cassini Spacecraft

  • Cassini flybyDec. 2000Galileo Orbiter33 orbitsDec. 1995 to Oct. 2003VoyagersPioneersUlyssesMagnetopause

  • Cassini Flyby of Jupiter

  • 2004 Cassini Reaches Saturn

  • Galileo:The End Game Must never hit Earth or Europa

    3 passes close to Ioto determine if Io has a magnetic field

    Hits Jupiter October 2003100 RjupiterSun

  • SMEX mission

    Earth-orbiting UV telescope to observe Io, the torus and Jovian aurora

  • FAST/Polar goes to JupiterRADIATION BELTS~$350M space physics mission to explore polar latitudes Jupiter Polar OrbiterParticles & Fields Instruments

  • Lets Keep Exploring!

  • Io Summary Tidal forces heat the interior, driving volcanism, resurfacing Io 100 times faster than Earth

    Silicate lavas erupt at temperatures >1800K

    Volcanic plumes feed a tenuous, patchy atmosphere of SO2 - and S2 and ?

    Complex interaction with Jupiters magnetosphereEscape of 1 ton/second of sulfur and oxygen ions3 million Amps of electrical current connect Io and JupiterIntense bursts of radio emission

  • HST Obervations of Ios SO2 AtmosphereVariable .. with volcanic activity?

  • The Io AuroraInfraredUltraviolet- energetic particles bombard atmosphere- wake emission extends half way around Jupiter

  • John Clarke - HSTDave Young- CassiniPlasma Exp.

  • IR, UV spot images

    Text -> implications - energy does get to ionosphere- but not just at Io footprint