Exploring Europa: A Potentially Habitable World Robert Pappalardo Jet Propulsion Laboratory California Institute of Technology Ph.D. ASU ‘94
Copyright 2015. All rights reserved. Government sponsorship acknowledged. The Planetary Ingredients for Life
water essential chemical elements energy stability The Galilean Moons
Europa
Io
Ganymede
Callisto
Galileo spacecraft, 1995-2003 Europa’s Surface
ridges chaos Europa’s Interior Tidal Flexing Tidal Heating Europa’s Magnetic Personality
Art by Michael Carroll Europa’s Induced Magnetic Field
orbit plane mag. equator field line at Europa vector at Europa
[animation by E. Sturm using JPL’s Jupiter Environment Tool] Ridges Bands
Animation by John Spencer, SwRI Bands Impacts
5 km Pwyll ImpactsImpacts
10 km TyreTyre Dark Spots Lenticulae
Mosaic by Orion Ice Convection
cold, stiff ice
warmer, flowing ice
100 K = -170 C = -280°F cold, stiff ice
warmer, flowing ice
260 K = -10 C = 8°F ocean Journey to Conamara Chaos Chaos
Mosaic by Orion Chaos
Illustration after B. Schmidt Active Plumes? Some Reactions That Can Power Life
• Photosynthesis (plants):
CO2 + H2O sugar + O2
• Aerobic respiration (animals):
sugar + O2 CO2 + H2O
• Iron oxidation: 2+ 1 + 3+ 2Fe + /2 O2 + 2H 2Fe + H2O
• Methanogenesis:
CO2 + 4H2 CH4 + 2H2O
• Sulfur reduction or oxidation:
H2SO4 + 4H2 H2S + 4H2O
CO2 + 2H2S CH2O + 2S + H2O
Chemosynthesis: Chemical reactions that can power life, in the absence of sunlight (without photosynthesis). Habitability: Ingredients for Life
Water e-, O+, S+, … • Probable saltwater ocean, implied by surface geology and magnetic field radiation-produced oxidants: • Possible lakes within the ice shell, produced O , H O , CH O by local melting 2 2 2 2 –170 C Chemistry • Ocean in direct contact with mantle rock, promoting chemical leaching • Dark red surface materials contain salts, probably from the ocean Energy • Chemical energy could sustain life • Surface irradiation creates oxidants • Mantle rock-water reactions could create reductants Geological activity hydrothermally produced reductants: • “Stirs the pot” H2S, H2, CH4, Fe • Could provide time for life to develop 22 Europa Mission Concept Europa Mission Science Goal: Explore Europa to investigate its habitability
Ocean & Ice Shell Reconnaissance
Composition
Geology NASA-Selected Europa Payload
MASPEX SUDA ICEMAG PIMS Europa-UVS Mass Spectrometer Dust Analyzer Magnetometer Faraday Cups UV Spectrograph sniffing the surface & plume sensing ocean sampling the plasma surface & plume/atmosphere atmosphere composition properties environment composition
MISE E-THEMIS EIS EIS IR Spectrometer Thermal Imager Narrow-Angle Camera Wide-Angle Camera surface chemical searching for hot spots surface mapping alien landscape in 3D fingerprints & color
REASON Ice-Penetrating Radar plumbing the ice shel l
Gravity Science confirming an ocean
Composition Geology Ice & Ocean Europa Mission Concept Overview
Low Gain Antenna (LGA) Thermal Shield Fanbeam Antenna (FBA) $"!, !%&$) !& Avionics Vault ,#
High Gain Antenna ) ! (HGA) !&$'! $
Batteries $$"+! . ! $%
Reaction Wheels "$&+* !$$ #&$" &$
)&$ %% #&$" &$
Solar Arrays !&" &$ Thermal Radiator % !%"$ Pressurant Tanks &$* " & )$"#/ #&$" $#
/ $ $ )%&&&"$ $* &, !* " )%,%& 22N Main Engine (x8)
$ %&#"&!' )! & 8 )!5455 $ %& )# &$$$ * 7 $5457 !")$ 67)$"# ,,% !#$ %% "! $ $, %% "!! 85459 0!, #&1 58 A Global Web of Fly-bys
• Multiple satellite gravity assists enables “global-regional coverage” of Europa from orbit around Jupiter • Current mission design consists of 42 low-altitude flybys of Europa from Jupiter orbit over 3.5 yr • Minimizes time in high radiation environment • Simple repetitive operations Europa Mission Concept Europa Mission Concept http://www.nasa.gov/europa