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EXPLORATION OF

Fran Bagenal

Laboratory for Atmospheric & Space Physics University of Colorado Boulder 50 Years of Discovery Since Apollo

1 NASA/JPL-Caltech/SSI/SwRI/MSSS/ASI/INAF/JIRAM/Björn Jónsson JUPITER BEFORE APOLLO

Ground-based monitoring of

1972 M. Foulkes

Giant Jupiter 1966 LPL by John Rogers 2 JUPITER BEFORE APOLLO

Cruikshank & Binder (1969) Spectra showed atmospheric constituents , , ?

Kuiper (1952)

3 JUPITER BEFORE APOLLO

1969 only 11 !

Post- brightening of – evidence of frost?

Binder & Cruikshank (1964) 4 JUPITER BEFORE APOLLO Burke & Franklin 1955 Hints of Jupiter's • Decametric Radio Bursts1955 • Decimetric Synchrotron Emission1959 Berge (1966)

Radio Bursts Triggered Jupiter has Magnetic by Io! Dulk (1965) Field Trapping Electrons 5 Dec 1973 & 11 Dec 1974 Magnetosphere

Smith et al. (1976) • Size=huge Fillius (1976) Simpson & • McKibben (1976) dominated • Strong Belts • absorption 6 Pioneer 10 Dec 1973 & 11 Dec 1974

Ganymede

Ted Stryk

7 Mar 1979 & 2 Jul 1979 Dynamics

8 Voyager 1 Mar 1979 & 2 Jul 1979 Io!

9 & Voyager- Io Torus Voyager Voyager UVS PLS In situ Emission Broadfoot et al. (1979) Bridge et al. (1979)

S+ optical emission First observed Kupo et al. (1976) Schneider & Trauger 199510 Voyager 1 Mar 1979 & 2 Jul 1979 Daniel Machacek

Bjorn Jonssen

Europa 11 Probe Dec 1995

• Lack of Water Ø Local? Sushil Ø Atreya Global? 12 Galileo 34 orbits: Mar 1995 – Sep2003 Maps of Callisto & Io

USGS 13 Galileo 34 orbits: Mar 1995 – Sep2003 HST O emission Ganymede Plasma UV Magnetic Flow Field! McGrath et al. 2013

Kivelson et al. 1996

Xia et al. 2015 Khurana et al. 2007 14 Galileo 34 orbits: Mar 1995 – Sep2003

Europa • High resolution images • Ocean detected via currents

NASA/JPL/SETI Institute 15 Cassini Dec 2000 • High resolution movie • UVIS variations of Io Plasma Torus Steffl et al. 2004

NASA/GSFC Scientific Visualization Studio, Cassini Imaging Team, 16 CICLOPS, Cosmos Studios, Andy Ingersoll Feb 2007

• Tvashtar volcanic eruption

• Passed 2500 RJ down magnetotail NASA/JHU-APL/SwRI

McComas et al. 2016 17 Jul 2016+ • Gravity: core diluted ...heavy elements mixed • structure

Connerney et al. 2018 Wahl et Moore et al. 2018 al. 2017 18 Juno's observations of microwaves coming from the interior show absorptionNH Concentration by ammonia Junoin a deep Jul 2016+ circulation pattern 3

• Deep • It's complicated! • Water next.... First hints of Juno-MWR Team deep circulation..... Juno-MWR Team 42 19 South Pole Juno Jul 2016+

Juno UVS – Gladstone – PJ18 Juno is testing ideas of how charged particles that bombard Jupiter's atmosphere are accelerated 20 Mura et Juno-JIRAM Juno Jul 2016+ al. 2017

John Spencer (SwRI)

Io Juno • Io Footprint Aurora • Juno flew through fluxtube .....with mega-Amp currents • Fluxes of ions & electrons .....both up and down 21 Juno-JIRAM North Juno Jul 2016+ 8 • Polar vortices • Persisted 20 months JunoCam JunoCam Citizen Science - Great success! 5 South 22 Future JUICE & Clipper

JUICE

23 Summary • Now 79 Moons! • 7 flyby missions, 2 orbiters, 1 probe • Interior & atmosphere highly structured need modeling • very different worlds • Europa most likely place to find life • Io – major science – mission please! • Magnetosphere temporal/spatial variations need multiple spacecraft

24 • Next 50 years??!! NASA/SwRI/MSSS/Gerald Eichstädt/Seán Doran