sign in sign up
<<
Home , Europa Imaging System, Imaging spectrometer, Magnetometer, Magnetometer (Juno), MARSIS

Europa Multiple Flyby Mission: Science Update to OPAG Bob Pappalardo, EMFM Project Scientist Jet Propulsion Laboratory, California Institute of Technology Feb. 22, 2017 0 © 2017 California Institute of Technology. Government sponsorship acknowledged. : What a World, What of Life? NASA-Selected Radiation Science Working Group Europa Instruments radiation environment

MASPEX Mass Spectrometer SUDA sniffing atmospheric Dust Analyzer ICEMAG composition surface & plume PIMS composition sensing ocean Faraday Cups Europa-UVS properties environment UV Spectrograph surface & plume/atmosphere EIS composition Narrow-Angle Camera + Wide-Angle Camera E-THEMIS MISE mapping alien landscape Thermal Imager IR Spectrometer in 3D & color searching for hot spots surface chemical fingerprints

REASON Ice-Penetrating plumbing the ice shell

Gravity Science Working Group confirming an ocean

Remote Sensing 1-2 High-Resolution, 3D Insight into Europa's Ice Shell and Current Activity The (EIS) will transform our understanding of Europa through unprecedented high-resolution images, near-global imaging, color mosaics, and 3D maps. EIS Investigation Addresses High-Priority Europa Science and Reconnaissance Goals for Multiple-Flyby or Orbiter Missions The powerful dual-camera imaging system is designed to respond to Europa science and reconnaissance goals prioritized by the NRC decadal survey for : • Characterize ice shell and ice-ocean interface – Geodesy to constrain ice shell thickness and ice-ocean interface • Understand formation of surface features and potential for EIS provides global (>95%) coverage at better than current activity 50 m/pixel for using the gimbaled – Near-global mapping at 50 m/pixel to characterize endogenic NAC (shown here) or for an orbiter via the WAC. landforms and global cross-cutting relationships – High-resolution (0.5 to 25 m/pixel) Europa Instrument80,000 kmOverview:100 km 80,000EIS km imaging and stereo of key features Range NAC Pushbroom Targets & Stereo NAC Frames for Global Coverage, – Topographic swaths to characterize (1-20 m/pixel) & WAC Pushbroom Stereo (20-50 m/pixel) & WAC Frames clutter in ice-penetrating radar (IPR) data Stereo & Color (10-420 m/pixel) for Geodesy (0.4-1.0 km/pixel) – Color photometry (surface and potential ath Low-Phase Photometry Sequence t P plumes) and high-resolution imaging to bi NAC, 60-200 m/pixel Or EIS-NAC Europa Imaging Systemidentify sites Narrow of current or recentAngle activity Camera NAC Pushbroom Off-Nadir WAC, 1-4 km/pixel Targets 20-70 m/pixel • Perform landing-site reconnaissance Plume Monitoring Geodesy Frames NAC, 70-800 m/pixel; WAC, 0.1-5 km/pixel O NAC, 0.2-0.8 km/pixel r – 1 m/pixel images and stereo of b it Distant Plume Monitoring Distant Surface Monitoring P Produces visible maps of the surface of Europa, a candidate landing sites t NAC, 1-5 km/pixel NAC, 1-5 km/pixel h – 11 m/pixel stereo/color context for High-Phase Mid-Phase Low-Phase to describesafety and science its valuetopography of future (includingAngle possibleAngle Angle landing sites EIS acquires a rich set of observations on every Europa encounter. Shown EISlander will provide landing comprehensive sites datasets), understandessential here its is Europa , Clipper orbit 31E24 and (trajectory 13F7), which approaches to fulfilling the goal of exploring Europa to at low phase angles (4-20°), passes closest to Europa at moderate phase investigateto search its habitability. for plumes. angles (20-130°), then departs at very high phase angles (130-170°). EISPI: Team Zibi Turtle The EIS team has extensive experience planning and analyzing spacecraft observations and generating topographicJohns Hopkinsand cartographic Applied data products. The team also has proven expertise developing and implementing experiments with similar challenges, e.g., flyby and/or orbital imaging, high-radiation environments, jitter, Laboratory and the scientific breadth necessary to ensure all requirements are met. The team is deeply committed to rapid data release and sharing the excitement of exploring Europa with the public.

Photo Credit: 12 m/pixel image EIS-WAC Europa Imaging System Wide Angle Camera Feb. 22, 2017 3 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: EIS

Europa Imaging System (EIS): Zibi Turtle, PI • Adding color capability to NAC – Scattered analysis shows that addition of color stripe filters will not impede plume detection – Increases opportunities to gimbal-target coordination with other instruments, extrapolating to small scales and other regions – 10 m color resolution from 1000 km – Can join the “joint scan” planned for each flyby giving 200 - 400 m/pixel hemispheric color – Extrapolate composition information to smaller scales and other regions Thera & Thrace: Galileo 220 m/pixel

Feb. 22, 2017 combined with 1.4 km/pixel color4 4 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: EIS

Europa Imaging System (EIS): Zibi Turtle, PI

Mannannán: Galileo 20 m/pixel combined with ~80-140 m/pixel color Ridged plains at ~25 m/pixel: WAC res from ~100 km; NAC res from ~2500 km

Feb. 22, 2017 5 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Overview: REASON & MISE

Radar for Europa Assessment and REASON Sounding: Ocean to Near-surface Uses VHF and HF bands to investigate Europa’s ice shell, subsurface ocean, plumes, tides, and potential landing sites

PI: Don Blankenship Produces maps of organic University of Texas compounds, salts, hot spots Institute for and ices to assess habitability of the ocean and investigate geologic history of the surface

Pegasus Airfield PI: Diana Blaney Jet Propulsion Laboratory

MISE Mapping for Europa

Feb. 22, 2017 6 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: REASON Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON): Don Blankenship, PI MARSIS Data, Using Clutter Model from Topography • REASON can use both topography from EIS stereo imaging and VHF to distinguish off-nadir- Subsurface Echo surface from subsurface reflectors Surface Clutter • Developed tools to quantify the suppression and interferometric Interferometry ineffective discrimination of surface clutter for distinguishing nadir – Assists spacecraft design and future analyses from off-nadir where <0 dB • Helps to clarify issues affecting REASON performance, esp. below 50 km

Feb. 22, 2017 7 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: MISE

Mapping Imaging Spectrometer Key compounds at MISE spectral resolution and sampling: for Europa (MISE): Diana Blaney, PI

• Thermal accommodation is critical to MISE – Cryocooler performance testing is currently underway • Examining trade of going from 2 to 1 cryocooler – Would reduce instrument mass, energy, cost • For low-altitude observations, there can be mismatches between MISE scan mirror rate and surface target motion – Addressed by downlinking uncompressed MISE cubes for ! the highest-res data Ice and salt Trace organics

Feb. 22, 2017 8 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Overview: Europa-UVS & E-THEMIS

Europa-UVS Europa Ultraviolet Spectrograph Characterizes thermal anomalies, active plumes, and surface properties Obtains ultraviolet images to support landing site assessment to explore Europa's and geology. composition and chemistry, search for plumes, and PI: Phil Christensen investigate connections with Arizona State University Europa’s environment

PI: Kurt Retherford Southwest Research Institute

E-THEMIS Europa Thermal Imaging System Feb. 22, 2017 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: Europa-UVS & E-THEMIS Europa Ultraviolet Spectrograph Solar Port KOZ (Europa-UVS): Kurt Retherford, PI • Working design to reduce angle to solar port, to permit smaller turns for solar occultations, while avoiding sun on SUDA KOZ Airglow/High-res • Designing open/close solar port door actuator Port FOV

Joint Scan Europa Thermal Imaging System E-THEMIS (E-THEMIS): Phil Christensen, PI FOV • Candidate detectors undergoing radiation and spectral response testing • Spacecraft scanning permits observing a range of local times of day on the surface Europa-UVS FOV Feb. 22, 2017 10 Pre-Decisional Information — For Planning and Discussion Purposes Only 10 D. Science InvestigationEuropa Instrument Overview: Background 1: Compositional Mapping

Europa is engulfed in a cloud of slow moving dust particles following 100 µm micrometeoroidSUDA impacts & MASPEX ballistic orbits, ejected by continual bombardment of hypervelocity generate ~500 kg ejecta/second interplanetary meteoroids. A dust mass spectrometer such as SUDA SUDA @ 25 km measures the composition of the ejecta particles and traces each of the detects 40 ejecta/s detected grains back to the surface (upper figure).Surface Hence, SUDA Dust will relate Analyzer SUDA Ejecta move on the measured composition to geological patterns and features on the ballistic trajectories . 109 ejecta/km2s How many surface samples can be collected? The number of detectable ejectaD. during Science a flyby Investigation or a low altitude orbit can be estimatedMeasures by the density the composition of dust profile of Europa's well characterized ejecta cloud based on Galileo measurements (Krüger et al., 1999; Krivov et al.,particles 2003). The ejecta and size constrains geological Backgrounddistribution 1: Compositional approximately follows Mapping a power law with a slope of ~2.4 and ranges from ~100 nm up to the typical size of the impactoractivities (about 100µm). on and below the surface of

Europa is engulfed in a cloud of slowThe moving total mass dust ejected particles in an following impact on Europa100 µm micrometeoroid far exceeds impactsthe mass of the 860 km ballistic orbits, ejected by continual impacting bombardment meteoroid of hypervelocity (~17,000 x) (Kempfgenerate et. al,~500 2012).Europa kg ejecta/second As an example, interplanetary meteoroids. A dust massduring spectrometer each of the suchtwo Europa as SUDA Clipper 25 km flybys shown in the middle SUDA @ 25 km E9 measures the composition of the ejectafigure particles SUDA and will traces collect each 5000 of samples the originating from this area. detects 40 ejecta/s Thera Sniffs Europa’s detected grains back to the surface (upper figure). Hence, SUDA will relate Macula the measured composition to geologicalHow patterns is a compositional and features on map the generated? By combiningEjecta many move on such PI: Saschaballistic trajectoriesKempf moon. measurements a compositional map of the surface can be generated. For atmosphere and

each particle detection, a two dimensional probability distribution is km 980 E6 109LASP, ejecta/km2s University of How many surface samples can be collected?derived The for its number origin of on detectable the surface. As an example, the middle figure Thrace Macula exosphere to determine ejectaD. during Science a flyby Investigation or a low altitude orbitshows can abe Monte-Carlo estimated by simulationthe density of SUDA measurementsColorado during Europa Boulder profile of Europa's well characterizedClipper ejecta 25 cloud km flybys based 6 and on 9 Galileoover the dark lobated features Thrace Macula their chemical measurements (Krüger et al., 1999; Krivovand Thera et al., Macula. 2003). The Each ejecta colored size dot indicates the origin of an ejecta Backgrounddistribution 1: approximatelyCompositional follows Mapping a powerdetected law with by SUDA a slope randomly of ~2.4 and launched from inside (red) and outside 420 km composition ranges from ~100 nm up to the typical size(yellow) of the the impactor feature. (about The lower 100µm). figure shows the resulting probability map The total mass ejected in an impact on Europafor the farorigin exceeds of the the detected mass of particlesthe from the dark features on Europa Europa is engulfed in a cloud of slow moving dust particles following 100 µm micrometeoroid impacts 860 km Probability for origin inside contour lines: ballistic orbits, ejected by continualimpacting bombardment meteoroid of (~17,000 hypervelocity x) (Kempf(redgenerate et. dots al, ~500 in2012). kg middle ejecta/second As plot) an example, if identified by their unique composition. SUDA interplanetary meteoroids. A dust massduring spectrometer each of the two such Europa as SUDA Clipper can25 km unambiguously flybys shown identify in the andmiddle characterize the composition of the ThraceE9 figure SUDA will collect 5000 samples originatingMacula and from TheraSUDA this Macula @ area. 25 km terrains. PI: Hunter Waite measures the composition of the ejecta particles and traces each of the detects 40 ejecta/s Thera detected grains back to the surface (upper figure). Hence, SUDA will relate Macula the measured composition to geologicalHow patterns is a compositional and features onmap the generated? What is By the combiningspatial resolutionEjecta many move of suchon a compositional map? Without knowledge Southwest ballistic trajectories moon. measurements a compositional map of ofthe the surface dust impactcan be speed, generated. the spatial For resolution is roughly given by the SC

each particle detection, a two dimensionalaltitude probabilityover the area distribution of interest. is The resolutionkm 980 of SUDA maps is evenE6 Research Institute 109 ejecta/km2s derived for its origin on the surface. higher,As an because example, SUDA the middledetermines figure the velocity componentThrace of dust particles How many surface samples can be collected? The number of detectable Macula ejecta during a flyby or a low altitude orbitshows can a be Monte-Carlo estimated by simulation the density of SUDAalong measurements the instrument during axis Europa by measuring its time-of-flight between the profile of Europa's well characterizedClipper ejecta 25 cloudkm flybys based 6 and on 9 overGalileo the darkentrance lobated grid features at the Thrace aperture Macula and acceleration grid at the target with an 55% measurements (Krüger et al., 1999; Krivovand Thera et al., Macula. 2003). The Each ejecta colored size dot accuracy indicates of the about origin 1%. of This an improves ejecta the resolution in the direction of the 75% distribution approximately follows a powerdetected law bywith SUDA a slope randomly of ~2.4 and launched S/C from velocity inside vector (red) by a and factor outside of 2. 420 km 95% Mass Spectrometer for ranges from ~100 nm up to the typical (yellow)size of the the impactor feature. (aboutThe lower 100µm). figure shows the resulting probability map The total mass ejected in an impact on forEuropa the originfar exceeds of the the detected mass of particles the from the dark 860features km on Europa Probability for origin inside contour lines: MASPEX Planetary Exploration impacting meteoroid (~17,000 x) (Kempf(red et. dots al, in 2012). middle As plot) an if example, identified by their unique composition. SUDA during each of the two Europa Clippercan 25 unambiguouslykm flybys shown identify in the and middle characterize theFeb. 22, 2017 composition of the Thrace 11 molecules and ions from theE9 Jovian , and dust impacts. These processes are respon- figure SUDA will collect 5000 samples originatingMacula and from Thera this Macula area. terrains. Pre-Decisional Information — For Planning and Discussion Purposes Only sible forThera the formation of strong oxidants (O2,H2O2) in irradiated ices, accumulation of molecules Macula How is a compositional map generated?What is Bythe combiningspatial resolution many of such a compositional and elements map? from Without (SOknowledge2, Na, K, Cl) together with chondritic and cometary materials containing measurements a compositional map ofof the the surface dust impact can be speed, generated. the spatial For bothresolution inorganic is roughly and given organic by the componentsSC (Carlson et al., 2009). Endogenic processes are responsi-

each particle detection, a two dimensionalaltitude over probability the area distribution of interest. is The resolutionkm 980 of SUDA maps is evenE6 derived for its origin on the surface. higher, As an because example, SUDA the middledetermines figure the ble velocity for thecomponent deliveryThrace of dust of non-iceparticles materials which are best manifested in disrupted surface features: Macula shows a Monte-Carlo simulation of SUDAalong measurements the instrument during axis byEuropa measuring ridges, its chaotic time-of-flight terrains, between pits, the and domes. Galileo and telescopic IR data suggests the presence of Clipper 25 km flybys 6 and 9 over the darkentrance lobated grid features at the Thraceaperture Macula and acceleration hydrated grid sulfate at the species: target with Mg an and Na sulfates together with55 sulfuric% acid hydrates (McCord et al., and Thera Macula. Each colored dotaccuracy indicates of theabout origin 1%. ofThis an improves ejecta the resolution in the direction of the 75% 1998; Carlson et al., 2009; Shirley et al., 2010; Brown and Hand, 2013). CO2 is reported in col- detected by SUDA randomly launchedS/C fromvelocity inside vector (red) by a andfactor outside of 2. 420 km 95% (yellow) the feature. The lower figure shows the resulting probability map ored non-ice materials (Hansen and McCord, 2008). The detection of Na and K in the exosphere for the origin of the detected particles from the dark features on Europa Probability for origin inside contour lines: (red dots in middle plot) if identified by their unique composition. SUDA can unambiguously identify and characterize the composition of the Thrace Macula and Thera Macula terrains. molecules and ions from the Jovian magnetosphere, and dust impacts. These processes are respon- sible for the formation of strong oxidants (O ,H O ) in irradiated ices, accumulation of molecules 2 2 2 2 What is the spatial resolution of a compositionaland elements map? from Without Io(SO knowledge2, Na, K, Cl) together with chondritic and cometary materials containing of the dust impact speed, the spatialboth resolution inorganic is roughly and given organic by the components SC (Carlson et al., 2009). Endogenic processes are responsi- altitude over the area of interest. The resolution of SUDA maps is even higher, because SUDA determines theble velocity for the component delivery of ofdust non-ice particles materials which are best manifested in disrupted surface features: along the instrument axis by measuringridges, its chaotic time-of-flight terrains, between pits, the and domes. Galileo and telescopic IR data suggests the presence of entrance grid at the aperture and accelerationhydrated sulfategrid at the species: target with Mg an and Na sulfates together with sulfuric55% acid hydrates (McCord et al., accuracy of about 1%. This improves the resolution in the direction of the 75% 1998; Carlson et al., 2009; Shirley et al., 2010; Brown and Hand95% , 2013). CO2 is reported in col- S/C velocity vector by a factor of 2. ored non-ice materials (Hansen and McCord, 2008). The detection of Na and K in the exosphere molecules and ions from the Jovian magnetosphere, and dust impacts. These processes are respon- sible for the formation of strong oxidants (O ,H O ) in irradiated ices, accumulation of molecules 2 2 2 2 and elements from Io (SO2, Na, K, Cl) together with chondritic and cometary materials containing both inorganic and organic components (Carlson et al., 2009). Endogenic processes are responsi- ble for the delivery of non-ice materials which are best manifested in disrupted surface features: ridges, chaotic terrains, pits, and domes. Galileo and telescopic IR data suggests the presence of hydrated sulfate species: Mg and Na sulfates together with sulfuric acid hydrates (McCord et al., 1998; Carlson et al., 2009; Shirley et al., 2010; Brown and Hand, 2013). CO2 is reported in col- ored non-ice materials (Hansen and McCord, 2008). The detection of Na and K in the exosphere

2 Europa Instrument Highlights: SUDA & MASPEX Incoming Ejecta Particle SUrface Dust Analyzer (SUDA): Sascha Kempf, PI • SUDA is oriented directly into dust ram at closest approach, when particle number density is highest • Sun must be out of FOV while making dust measurements • Improving TRL on Ir-coated detector through prototype testing • Investigating innovative ways to lower instrument mass TOFMS MAss Spectrometer for Planetary EXploration Cryotrap Calibration Gas Detector (MASPEX): Hunter Waite, PI Radiator Gas Inlet Reflectron • VAT valve to reduce leak rate, facilitating cryosample analysis System • Performing lifetime testing on ion pump • Fabricating parts for detector • Contamination control is key – spacecraft cleanliness, FOV/KOZ incursions, thruster products

Feb. 22, 2017 12 Pre-Decisional Information — For Planning and Discussion Purposes Only Section D—Science Investigation

D.1 INVESTIGATION BACKGROUND, assessment of ocean characteristics from a GOALS, AND OBJECTIVES three-axis stabilized spacecraft for either an orbiter or flyby mission. The Interior Characterization of Europa using MAGnetometry (ICEMAG) investigation measures D.1.1 BACKGROUND Europa’s induction response at multiple frequencies Europa, the smallest of the Galilean to resolve outstanding questions concerning its ice satellites, has long been suspected of harboring shell thickness and ocean properties pertaining to a liquid subsurface ocean that could be a its habitability, while also measuring atmospheric potential habitat for life (see Pappalardo et al. composition, loss, possibleSection D plumes,—Science Investigationand coupling of 2009 for a recent review). Europa’s low Europa to ’s magnetosphere and ionosphere average density (3.013±0.005 kg/m3) and D SCIENCE INVESTIGATION rate. ICEMAG’s precise measurements over a broad frequency range enable identification of flattened rotational shape constrain the radial EXECUTIVE SUMMARY The discoverythe molecular byspecies the being Galileo lost from mission Europa’s of thickness of a combined ice/water layer to be surface, yielding new into plume Characterizing Europa’s watery interiorpotential is subsurface oceans on Europa, 80170 km (Anderson et al. 1998, Schubert et Ganymedeactivity and and Callisto sources. was a game-changer in critical to evaluating its potential habitability. measurements also determine al. 2009). Identification of electromagnetic The discovery of Europa’s near-surface the searchthe electricalfor habitable currents associated zones in with our coupling solar induction (sounding) signatures excited by conductivity by induction studies with thesystem. of As plume a consequence,s to the corotating magnetosphericEuropa has become Galileo magnetometer is consistent with other plasma and coupling of Europa to the Jovian Jupiter's magnetic field in five close Europa geophysical evidence for an ocean sucha as prime non- ionosphere target for, as demonstratedfurther exploration by the auroral to flybys provided evidence for a subsurface synchronous rotation of Europa’s surfaceunderstand and spot at its the internal foot of the structureEuropa flux tubeand in the Fig. ocean (Khurana et al. 1998, Zimmer et al. its active tectonics (Pappalardo et al. 2009).exchange D-1. of material between the deep interior Magnetic induction is a powerful tool for The ICEMAG instrument combines the 2000, Kivelson et al. 2000), which is also probing the subsurface. More discoveriesand are the surface. While Galileo data indicated latest spaceborne magnetometer technology supported by evidence for non-synchronous expected from a mission dedicated to Europa the presencewith the of proven a conducting experience and subsurface expertise of the ocean, rotation of the outer ice shell relative to the and an instrument designed to measure and activeJPL /UCLAresurfacing team. The on advent Europa, of laser -thepumped data Europa’s induction response at multiple sensors and advances in digital signal silicate mantle (e.g. Greeley et al. 1998, frequencies with high accuracy. Our were inadequatesampling enables to reveal an innovative the detailedmulti-sensor structure Geissler et al. 1998). investigation, the Interior Characterizationof ofthe icemagnetome and oceanter to be layers flown that. The is able ICEMAG to Europa using MAGnetometry (ICEMAG) The principle of electromagnetic induction investigationmonitor spacecraftproposed here and formaintain the absoluteEuropa definitively assesses the ice shell thickness and accuracy of the measurement at a level of is illustrated in Fig. D-2. The physics of the conductivity and thickness of the mission is uniquely designed to quantitatively < 0.1 nT over time scales of years, without electromagnetic diffusion in a sphere with a PIMS is key to determining Europa’s ice shell PLASMA INDUCTION subsurface ocean. This knowledge informmeasurs especial the thicknessmaneuvers such of as the spacecraft ice shell, rolls. and the DOMINATED DOMITATED models of Europa’s thermal evolution and multi-layered conductivity distribution are well thickness, ocean thickness, and salinity by allows evaluation of processes that havedepth, cycled thicknessThe ICEMAG and magnetometer salinity of presents the global a known (Parkinson 1983, Zimmer et al. 2000, material between the depths and the surface.Europan leap ocean.-forward It in monitor capability, sdesigned the loss from of the accurately correcting the magnetic induction start to be efficiently radiation-hardened and to Khurana et al. 2002). For a uniform primary signal for plasma currents around Europa. Europa resides within Jupiter’s immenseEuropa’s deliver tenuous a data setatmosphere of unparalleled and accuracy the forcoupling magnetosphere (Fig. D-1). Europa’s interaction either a flyby or an orbiter mission. Its data field, the induced field is dipolar (left panel) PIMS measures the plasma surrounding Europa to characterize with Jupiter’s magnetized plasma provideofs Europa to its plasma environment. The the magnetic fields generated by plasma currents. These plasma combine synergistically with radar sounding of and shields the interior of the body from the information on Europa’s composition becausetechniques the ice for shell, accomplishing spectroscopic measurements these objectives of currents mask the inductionEuropa response of the subsurface ocean. TheInstrument Overview:its atmosphere derives from bothPIMS surface & ICEMAGambient field (center). Galileo magnetometer were developedthe surface, andby interiormembers density of from the gravity. proposal plasma contributions to the magnetic field exceed the induction materials and venting from the interior. data show that the induced field at Europa is signal in all but a few portions of some flybys and are always at least Atmospheric composition can be evaluatedteam by to interpretThe ICEMAG Galileo team brings magnetometer decades of indeed dipolar and global, and its strength and 30% of the induction signal. measuring the frequencies of electromagneticobservations experience. The with experience spaceborne magn ofetometry the ICEMAG and generated as the constituents interact magnetic data analysis to the Europa mission. direction varies in response to the changing The interaction of the co-rotating Jovian plasma with Europa and team onICEMAG , data Galileo will reveal and the structure Cassini of has been the neutral matter present in its vicinity produces dynamic pressure with the Jovian corotating plasma; the power primary field, ruling out a permanent dynamo of these waves indicates the atmosphericapplied loss Europa’sto design interior an, theintegrated composition multi and loss-sens of or gradients on multiple scale lengths. Those gradients drive plasma its atmosphere and the coupling of Europa to field and remanent as the main currents that modify the measuredPlasma magnetic fi eld in exactlyInstrument the region for Magnetic Sounding magnetometerthe magnetosphere. that enables a definitive wherePIMS the inductive fi eld from Europa’s subsurface ocean is greatest. field source Variations in the density and velocity of this plasma produce tens of (Kivelson et al. nT changes in the observed magnetic fi eld resulting in ~50-100 km Figure D-1. Jupiter's magnetospheric field lines are shown in uncertainties in the ocean thickness determinations. blue, along with magnetic flux tubes (in pink) associated with Io 2000). (left), Europa (right) and Ganymede (center), and the Io torus in Europa’s PIMS accuracy in measuring the Jovian plasma red. Jupiter’s tilted magnetic field and Europa's slightly Measures the plasma MagnetormeterMagnetormetesurrounding Only eccentric orbit result in a strong time-varying (inducing) atmosphere is and Europa ionosphere translates into accurate magnetic field at Europa that probes the depth, thickness and believed to derive PIMS + conductivity of its ocean. Jupiter’s plasma torus is fed by the from surface ocean thickness and salinity determinations.Europa to characterize its subsurfaceMMagnetometeragnetome atmospheres of both Io and Europa, as shown by the bright PIMS uses three Faraday Cups (FCs) in one sensor to measure the 50-100 km spots within the inset auroral image (from HST), indicating sputtering and plume plasma mass density and flow velocity to 15% or better accuracy.ocean, its ice Uncertaintyshell, and plumes coupling of the flux tubes of Io, Europa, and Ganymede to the activity from vents. The measured plasma properties and well-tested computer plasma torus. ICEMAG probes Europa’s ocean, its atmosphere, simulations, used iteratively, establish the contributions to the total and its coupling to Jupiter and the Jovian magnetosphere. The atmosphere is magnetic field of plasma currents to 15% accuracy in the total ionized and interacts magnetic field. Taking advantage of the differing spatial forms of 10 km Figure D-2. (Left) The time-varying magnetic field of Jupiter (green lines) generates fields from plasma and induction currents, our inversion scheme D/E-1 with Jupiter’s Uncertainty Use or disclosure of information contained on this sheeteddy is subject currents to the restriction (orange on the lines) Restrictive that Notice flow page on of this the proposal. surface of Europa’s ocean, generating an is able to markedly increase the accuracy with which the inductivePI: Joe Westlake corotating plasma; field signature can be characterized (2% or better), resulting in induced field (red lines) that reduces the primary field in the interior of the body. (Center) escaping ions gyrate estimated induction field errors of 2-4 nT, enabling 1-5 kmJohns accuracy Hopkins Applied The primary and induced fields combine such that the time-varying Jovian magnetic field in determining the ice shell thickness and 10 km accuracy for the avoids the conductingInfers obstacle location, (Europa). This inductionthickness response takesand place within a around Jupiter’s ocean thickness. Physics Laboratory background static southward field (Right) that can penetrate through Europa’s interior. PIMS Investigation 1: Determine Europa's PIMS Investigation 2: Understand the PIMS Investigation 3: Understand conductivity of Europa’s ocean magnetic induction response, corrected for mechanisms responsible for weathering how Europa influences its local space D/E-2 plasma contributions, to estimate ocean and releasing material from Europa's environment and Jupiter's magnetosphere Use or disclosure of information contained on this sheet is subject to the restriction on the Restrictive Notice page of this proposal. salinity and thickness. (NRC Decadal surface into the atmosphere and (NRC Decatdal Objective 5). using electromagnetic sounding Objectives 1, 2 & 5). ionosphere (NRC Decadal Objective 3).

PI: Carol Raymond Jet Propulsion Laboratory

Interior Characterization of Europa ICEMAG using Magnetometry Feb. 22, 2017 13 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa Instrument Highlights: PIMS &ICEMAG Plasma Instrument for Magnetic Sounding (PIMS): Joe Westlake, PI • 2 sensors, each with 2 Faraday cups (90° FOV each) • Moving electronics to within cups, improving grounding • Modeling demonstrates mag cleanliness can be relaxed • Developing tools to assess potential science impacts of spacecraft charging, which can affect ion or measurements Interior Characterization of Europa using Magnetometry (ICEMAG): Carol Raymond, PI • Optimizing location on the boom of the FG and SVH sensors • Working with spacecraft team on sensor attitude knowledge 2 x Scalar/Vector Helium (SVH): and magnetic cleanliness requirements alternating scalar and vector Feb. 22, 2017 2 x Flux Gate (FG): vector 14 Pre-Decisional Information — For Planning and Discussion Purposes Only Magnetometer Boom Deployment

Deployment Stowed Boom • Single hinge design sweep • Simple deployment • Fewer unknowns reduces magnetometer pointing uncertainty

Deployed Boom

Feb. 22, 2017 15 Pre-Decisional Information — For Planning and Discussion Purposes Only Spacecraft Deployment Sequence

Feb. 22, 2017 1616 Pre-Decisional Information — For Planning and Discussion Purposes Only Europa “Clipper”: Synergistic Science

Feb. 22, 2017 Gravity Magnetometry + Plasma Imaging Infrared Thermal Radar Ultraviolet Gas + Dust Mass Spectroscopy Gravity Magnetometry + Plasma Imaging Infrared Thermal Radar Ultraviolet Gas + Dust Mass Spectroscopy Europa Flyby Animation

Pre-Decisional Information — For Planning and Discussion Purposes Only