Science from the Europa Clipper Mission Concept: Exploring
the Habitability of Europa
D. Senske1, L. Prockter2, R. Pappalardo1, M. Mellon3, W. Patterson2, S. Vance1,
B. Cooke1, and the Europa Study Team
1Jet
Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109, 2Johns Hopkins
Applied Physics Laboratory, Laurel, MD, 20723, 3Southwest Research Institute, Boulder, CO 80302.
1/31/13
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
1
Background
• The NRC Decadal Survey deemed the Jupiter Europa Orbiter
(JEO) mission concept to be of extremely high science value,
but unaffordable, and viable descoped options were requested
• A 1.5 year study developed mission options that retain high
science value at significantly reduced cost: the “Clipper”
(multiple flyby), a simplified Europa Orbiter, and a Lander
(report to NASA, May 2012)
• Focus now on Europa Clipper concept
The Europa Clipper
(Multiple-Flyby in Jupiter Orbit)
1/31/13
Europa Orbiter
Europa Lander
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
2
Europa Science:
Goal, Habitability Themes, and Objectives
• Goal: Explore Europa to investigate its habitability
• Habitability Themes:
water
– Water: Solvent to facilitate chemical reactions
– Chemistry: Constituents to build organic molecules
– Energy: Chemical disequilibrium for metabolism
habitability
chemistry
• Objectives:
energy
– Ocean: Existence, extent, and salinity
– Ice Shell: Existence and nature of water within or
beneath, and nature of surface-ice-ocean exchange
– Composition: Distribution and chemistry of key
compounds and the links to ocean composition
– Geology: Characteristics and formation of surface
features, including sites of recent or current activity
1/31/13
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Pre-Decisional — For Planning and Discussion Purposes Only
3
Europa Clipper: Science Investigations
and Model Planning Payload
Science
Objective
Ocean & Ice
Shell
Composition
Geology
Key Science Investigations
Similar
Instrument
Time-varying gravity field through Doppler tracking, to detect
ocean and determine interior structure.
Radio Sub-system
(RS); Independent
Gimbaled Antenna
Magnetic induction response, to derive ocean thickness and
salinity. Local plasma and electric field, to support magnetic
induction experiment.
Magnetometer
(MAG) with
Langmuir Probe
(LP)
Juno
MAG
Sounding of dielectric horizons at two frequencies, to search
for shallow water and the ocean.
Ice-Penetrating
Radar (IPR)
MRO
SHARAD
Visible and near-infrared spectroscopy, for global mapping
and high-resolution scans, to derive surface composition.
ShortWave IR
Spectrometer
(SWIRS)
LRO M3
Elemental, isotopic, and molecular composition of the
atmosphere and ionosphere, during close flybys.
Neutral Mass
Spectrometer
(NMS)
Nozomi
Medium to High resolution stereo imagery, to characterize
geological landforms, and to remove clutter noise from IPR
data.
Topographical
Imager (TI)
Floor model
instrument
1/31/13
Model
Instrument
Baseline model
instrument
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
Rosetta
LAP
New Horizons
Ralph/MVIC
4
Europa Clipper Concept Summary
Jan. 2013
Operations Concept:
- 32 low altitude flybys of Europa from Jupiter
orbit over 2.3 years
- Detailed investigation of globally distributed
regions of Europa
- Simple repetitive science operations
- Addition of high resolution reconnaissance
camera and thermal imager
Magnetometer
Science:
Objective
Ice Shell
Ocean
Composition
Geology
Recon
Clipper
Enhanced w Recon





Payload:
Instrument
Floor
Baseline
1/31/13
Clipper
Enh w Recon
IPR
SWIRS
TI
NMS
MAG
LP
GS
Recon
Thermal
Langmuir Probe (LP)
(x2)
Neutral Mass
Spectrometer (NMS)
Ice Penetrating
Radar(IPR)
Thermal Imager
(Thermal)
Shortwave Infrared
Spectrometer
(SWIRS)
Recon Camera
(Recon)
Topographical
Imager (TI)
(Mag)
Gravity Science
Antenna (GS)
Technical Margins
48%
40%
62%
Mass
Power
Data
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Innovative Mission Design
• Dense, globally distributed network of
intersecting ground tracks
• Enables globally distributed coverage
through multiple flybys
• Minimizes time in high radiation
environment
Multiple Europa Flybys
minimize radiation exposure
Flyby groundtracks
Europa
Orbit
Radiation
Belts
1/31/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Model Instrument Surface Coverage
SWIR Spec. - Low Res
Ice Penetrating Radar
––––––
––––––
SWIR Spec. – High Res
25 – 400 km
400 – 1,000 km
(primary data collection)
(extended data collection)
Topographic Imager (altitudes ≤4000 km)
High-res swaths at better than 100 m/pixel
1/31/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Europa Clipper Operations Concept
Simple and Repetitive
1.
Magnetometer and Langmuir Probes
– Continuous measurements
2.
ShortWave InfraRed Spectrometer (SWIRS)
– Global low resolution scan below 66,000 km altitude
– Targeted high resolution scan below 2,000 km altitude
– Passive below 1,000 km altitude
3.
Gravity Science
– Measurements below 28,000 km altitude
4.
Topographical Imager (TI)
– Pushbroom stereo imaging below
1,000 km altitude
– Lower res. pushbroom imaging
between 4,000 and 1,000 km altitude
5.
Ice Penetrating Radar (IPR)
– Surface scans below 1,000 km altitude
6.
Mass Spectrometer (NMS)
– In situ scan below 1,000 km altitude
7.
Recon Camera
– High resolution imaging below
105 km altitude
8.
Thermal Imager
– Pushbroom thermal imaging
below 60,000 km
1/31/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Key Science Questions for Europa
Science Question
1. What are the properties and characteristics of Europa’s ocean?
Objective
Clipper
Ocean
✓
✓
✓
✓
2. How thick is the icy shell?
Ice Shell
3. Is there near-surface water within the ice shell?
Ice Shell
4. What is the global distribution of geological features?
Geology
5. Is liquid water involved in surface feature formation?
Geology/Ice Shell
6. Is the icy shell warm and convecting?
7. What does the red stuff tell us about ocean composition?
8. How active is Europa today?
9. What is the plasma and radiation environment at Europa?
Ice Shell
Composition
Geology/Ice Shell
✓
✓
✓
✓
Ocean/Composition
10. What is the nature of organics and salts at Europa?
Composition
11. Is chemical material from depth carried to the surface?
Composition
✓
✓
12. Is irradiation the principal cause of alteration of Europa’s
surface material through time?
Composition
✓
1/31/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Programmatic Need for Feed-Forward
Reconnaissance Data Sets
• Reconnaissance data is necessary to
feed forward to a future lander mission:
required to evaluate landing safety
Observation
1/31/13
Cassini Enceladus 4 m/pixel
Purpose
High Resolution
Imaging
Map block abundance.
Stereo Imaging
Maps surface slopes for lander
tilt hazard, terrain relative
navigation.
Thermal IR
Imaging
Verify visible block abundance &
extrapolate to submeter scale.
(Brightness
Temperature and
Bolometric Albedo)
Validate average surface
roughness & extrapolate.
Characterize ≥ meter-scale
surface roughness.
Identify regolith cover.
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
Galileo
PPR
10
Europa Clipper Configuration
Langmuir Probe (LP) (x2)
Ice Penetrating
Radar(IPR)
Shortwave Infrared
Spectrometer (SWIRS)
Neutral Mass
Spectrometer (NMS)
Magnetometer
(Mag)
Thermal Imager
(Thermal)
Gravity Science Antenna
(GS)
Recon Camera (Recon)
Topographical Imager (TI)
1/29/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Europa Clipper Spacecraft
Benefits of Modular Configuration
• Implementation flexibility
– Parallel integration paths
– Module level integrated testing
during Phase C
– Isolates implementation issues at
the module level
• Robust schedule management
– Decouples qualification testing
until late in integration flow
– Allows for integration of ASRGs at
KSC
High Gain
Antenna
Star Tracker
(x2)
Avionics
Module
Reaction
Wheels (x4)
Avionics
Vault
Fuel
Tank
(x2)
Propulsion
Module
Thruster
Cluster
Assemblies
(x4)
• Smooth funding profile
– Minimizes peaks in project funding
profile
– Allows flexible phasing of module
implementation schedules
Oxidizer
Tank (x2)
Main
Engine
ASRG Control
Electronics (x4)
He Pressurant
Tank (x2)
Power
Source
Module
ASRG (x4)
1/29/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Radiation Mitigation Approach
Effective
Shield
Thickness
ß
Tank Wall
100 mil Al
Resulting
End of Mission
Dose
2.1 Mrad
(End of Mission Total Dose)
Propellant
200 mil Al
900 krad
Primary
Structure
400 mil Al
350 krad
600 mil Al
150 krad
800 mil Al
110 krad
1000 mil Al
80 krad
Vault
Chassis
Card
Location
(End of Mission Total Dose)
Allows use of existing industry geosynchronous class parts
1/29/13
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Pre-Decisional — For Planning and Discussion Purposes Only
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Power System Options
ASRG: Advanced Stirling Radioisotope Generator
-
Recommended by Planetary Decadal Survey
Technical issues need resolution for compatibility
with Europa Mission
Reliability not yet demonstrated; high per unit cost
-
Solar: Foldout Panel Solar Arrays
-
11.4 m
-
25.8 m
Technical issues must be resolved before determining
feasibility for Europa Mission
Reliability uncertain in high radiation environment.
Highest mass, lowest cost solution.
3.0 m
MMRTG: Multi-Mission Radioisotope Thermoelectric Generator
1/31/13
JEO baseline power source still feasible for redesigned Europa Mission
Highest 238Pu usage; concern diminished by 238Pu production restart
Demonstrated high reliability
Mass and cost impact bounded by Solar and ASRG
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
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Europa Clipper Cost Estimates
Cost: Phases A-F, no LV (FY15$)
Model
May 2012:
No Ocean
Science
or Recon
(ASRG)
May 2012:
Aerospace
CATE
(ASRG)
Oct. 2012:
w/ Ocean
Science &
Recon
(ASRG)
PRICE-H
$1.96B
$2.11B
$2.07B
SEER-H
$1.91B
$2.11B
$2.05B
Performed cost modeling as was done for NRC Planetary Decadal Survey
(Aerospace CATE) in addition to other parametric models as a check
• Changes from May 2012 to Oct. 2012 cost estimates:
– Updated Flight System cost estimates based on Oct. 2012 Master Equipment Lists
(MELs)
– Updated instrument cost estimate for IPR based on independent assessment
– Updated instrument cost estimates for all other instruments using NICM (subsystem
mode)
– Included additional instrument costs as applicable for Ocean Science & Recon
– Updated science and operations estimates
1/31/13
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged. The cost information contained in this document is of a
budgetary nature and is intended for informational purposes only. It does not constitute a commitment on the part of JPL and/or Caltech.
Pre-Decisional — For Planning and Discussion Purposes Only
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Assessment of Clipper by NRC and
NASA Committees
• Committee on Astrobiology and Planetary Sciences (CAPS) Assessment
to Planetary Science Subcommittee (PSS) (10/3/12):
– The Europa study team has developed excellent orbiter and flyby (“Clipper”)
concepts that are robust and feasible, and are responsive to the Decadal
Survey, the current budget constraints, and the need for balance in the
Planetary Program
– The multiple flyby “Clipper” element is favored because it addresses the
preponderance of the science objectives laid out in the Decadal Survey
– Independent review by a CATE process (the same used in the Decadal
Survey) affirms that the costs for the orbiter and Clipper are credible and that
the risk is low
– The Clipper mission has excellent scientific value
– Clipper mission concept is well thought out and realistic
– Radiation issues have been well addressed
– High resolution imaging, if possible without significant growth in cost or
complexity, would be an excellent “feed forward” element for a future lander
mission
1/31/13
Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.
Pre-Decisional — For Planning and Discussion Purposes Only
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Europa Clipper