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1Jet Propulsion Laboratory,
California Institute of Technology
2Applied Physics Laboratory,
Johns Hopkins University
Europa Clipper Update CAPS
March 4, 2014
Barry Goldstein1
Robert Pappalardo1
Brian Cooke1
Tom Magner2
Louise Prockter2
Dave Senske1
Copyright 2014. All rights reserved. Pre-Decisional — For Planning and Discussion Purposes Only
2
The Ocean That Beckons
“Europa, with its probable vast subsurface ocean sandwiched
between a potentially active silicate interior and a highly
dynamic surface ice shell, offers one of the most promising
extraterrestrial habitable environments, and a plausible
model for habitable environments beyond our solar system”
The Planetary Decadal Survey
3/4/14
Overview
• Key work accomplished since the last CAPS meeting
– NASA selected 15 Instrument Concepts for Europa Exploration (ICEE)
teams
• Europa team has had fruitful interactions clarifying mission accommodations,
operational and other constraints.
• Team has learned a great deal about the needs of the notional payloads for our
mission
– Conceived a more cost effective way of performing the gravity science
investigation by using fixed fan beam antennas
– Performed science evaluations of the latest mission trajectory
• Have now baseline 13F7 as target orbital tour
– Initiated science and technical risk reduction activities
– Conducted an independent mission solar power feasibility review
– Continued assessments with the Space Launch System (SLS) Program
Office on a potential launch vehicle
3/4/14 3 Pre-Decisional — For Planning and Discussion Purposes Only
Preliminary Concept Review
and Mission Concept Review
• Will conduct the PCR (next week) to focus on technical approach
• Technical designs & products are sufficiently mature for MCR
– Science traceability mission requirements flow down completed
• Top level requirements exist and have been flowed to system level
– Technology/engineering development risks understood and being mitigated
• Significant effort in process to mature the programmatic plan for the MCR
– MCR has been approved by NASA and is scheduled for September 16-18,
2014
– In preparation for this review, Pre-Project has begun development of
integrated master schedule (>1,600 line item) and conducted a
implementation workshop in early January • Outcome of this workshop as necessitated with Pre-Project moving earliest launch opertuinity
to May of 2022.
3/4/14 4 Pre-Decisional — For Planning and Discussion Purposes Only
Top Level Schedule
(May 2022 Launch)
3/4/14 5 Pre-Decisional — For Planning and Discussion Purposes Only
Europa Science Definition Team
• Full Science Definition Team (SDT) engaged
– 20 scientists from 7 research institutions and 4 NASA Centers
– Ensures that a broad range of expertise is represented in discussions
of science maturation during formulation phase
• Recent SDT telecons
– Trajectory update
– Reconnaissance observation planning update
– Discussion of Europa plume report
• Recent and planned In-person meetings
– Feb. 4, 2014: Implications of possible plumes for traceability matrices
– Jun. 2–3, 2014: Community input and discussion on plume implications
• Additional individual and group discussions of questions and issues
pertinent to science and recon traceability
• Recent presentations to SDT are publicly posted
– http://solarsystem.nasa.gov/europa/technical.cfm
3/4/14 6 Pre-Decisional — For Planning and Discussion Purposes Only
Europa Clipper Goals and Objectives
• Science Goal: Explore Europa to investigate its habitability
– Ocean & Ice Shell: Characterize ice shell and subsurface water, including heterogeneity, ocean properties, and surface-ice-ocean exchange
– Composition: Understand habitability of Europa's ocean through composition and chemistry
– Geology: Understand formation of surface features, including sites of recent or current activity, and characterize high science interest localities
• Reconnaissance Goal: Characterize Safe and Scientifically Compelling Sites for a Future Lander Mission to Europa
– Distribution of surface hazards, load-bearing capacity of surface, structure of the subsurface, and regolith thickness
– Composition of surface materials, geologic context, potential for geologic activity, proximity of near surface water, and potential for active upwelling of ocean material
Science Traceability Matrix
8 Pre-Decisional — For Planning and Discussion Purposes Only
3/4/14
Goal Objective Investigation
Exp
lore
Eu
rop
a to
in
ves
tig
ate
its
hab
itab
ilit
y
Ice
Shel
l an
d O
cean
Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange.
IO.1 Characterize the distribution of any shallow subsurface water and the
structure of the icy shell.
IO.2 Determine Europa's magnetic induction response to estimate ocean salinity
and thickness.
IO.3 Search for an ice-ocean interface.
IO.4 Correlate surface features and subsurface structure to investigate processes
governing material exchange among the ocean, ice shell, surface, and
atmosphere.
IO.5 Determine the amplitude and phase of gravitational tides.
IO.6 Characterize regional and global heat flow variations.
Co
mp
osi
tio
n
Understand the habitability of Europa's ocean through composition and chemistry.
C.1 Characterize the composition and chemistry of the Europa ocean as expressed
on the surface and in the atmosphere including potential plumes.
C.2 Determine the role of Jupiter's radiation environment in processing materials
on Europa.
C.3 Characterize the chemical and compositional pathways in Europa's ocean.
Geo
log
y
Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities.
G.1 Determine sites of most recent geological activity, including potential
plumes, and characterize localities of high science interest.
G.2 Determine the formation and three-dimensional characteristics of magmatic,
tectonic, and impact landforms.
• Objectives are prioritized, and Investigations are prioritized within
each Objective
• Bold: Recent SDT edits to ensure plumes are explicit
Pre-Decisional — For Planning and Discussion Purposes Only
Reconnaissance Traceability Matrix
Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
Goal Objective Investigation
Char
acte
rize
Saf
e an
d S
cien
tifi
call
y C
om
pel
ling
Sit
es f
or
a F
utu
re L
ander
Mis
sion t
o E
uro
pa
Lan
din
g S
afet
y
Assess the distribution of surface hazards, the load-bearing capacity of the surface, the structure of the subsurface, and the regolith thickness.
SL.1 Determine the distribution of blocks and other roughness elements
within a potential landing site at scales that represent a hazard to
landing.
SL.2 Determine the distribution of slopes within a potential landing site over
baselines relevant to a lander.
SL.3 Characterize the regolith cohesiveness and slope stability within
a potential landing site.
SL.4 Determine the regolith thickness and whether subsurface layering is
present within a potential landing site.
Sci
enti
fic
Val
ue
Assess the composition of surface materials, the geologic context of the surface, the potential for geologic activity, the proximity of near surface water, and the potential for active upwelling of ocean material.
SV.1 Characterize the composition and chemistry of potential landing sites
with an emphasis on understanding the spatial distribution and
degradation state of endogenically derived compounds.
SV.2 Characterize the potential for recent exposure of subsurface ice
or ocean material vs. degradation of the surface by weathering and
erosion processes and provide geologic context for potential landing
sites.
SV.3 Characterize the potential for shallow crustal liquid water beneath or
near potential landing sites.
SV.4 Characterize anomalous temperatures (that are significantly out of
equilibrium with expected nominal diurnal cycles) indicative of current
or recent upwelling or outgassing at or near potential landing sites.
9
• Prioritization is at the measurement level
• Bold: Recent edits to make plumes explicit
Model Payload
10
Magnetometer &
Langmuir Probes sensing ocean salts
Gravity Science confirming an ocean
Topo Imager alien landscape in 3D
IR Spectrometer chemical fingerprints
Ice-Penetrating
Radar plumbing the ice shell
Neutral Mass
Spectrometer sniffing the atmosphere
Ice & Ocean
Composition
Geology
Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
Reconnaissance
Imager preparing for future landing
Thermal
Imager preparing for future landing
Reconnaissance
Notional Europa Flyby
3/4/14 11 Pre-Decisional — For Planning and Discussion Purposes Only
Comprehensive Surface Coverage Globally Distributed Regional Coverage by Model Instruments
12
Infrared Spectrometer
Ice Penetrating Radar
Topo Imager (alt. ≤4000 km)
Ground Tracks
Pre-Decisional — For Planning and Discussion Purposes Only. 3/4/14
Reconnaissance at High Resolution Topo Imager, Recon Camera, SWIRS (E6 Flyby)
Recon Camera stereo pairs SWIRS
hi-res
“bowties”
Topo Imager
Coverage
Pre-Decisional — For Planning and Discussion Purposes Only 13 3/4/14
Thrace
Thera
Current Europa Clipper Spacecraft
Configuration
14
Langmuir Probe
Magnetometers
Ice Penetrating Radar antenna
(17.5 m)
Pressurant
Tanks MMRTG (baseline)
Sun Sensors 3m High Gain Antenna
Surface Mapping Instruments • Thermal Imager
• Shortwave IR Spectrometer
• Topographic Imager
• Recon Camera
Neutral Gas Mass Spectrometer
Vault
Reaction Wheel
Thruster Cluster Magnetometer Boom
(10.0 m) Launch Vehicle Separation Interface
Thermal
Control
Radiator
Heat
exchangers
.
1.16m
5.85m
Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
“The United States shall develop and use space nuclear power systems
where such systems safely enable or significantly enhance space
exploration or operational capabilities.”
National Space Policy of The United States of America
June 28, 2010
Solar Option
Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14 15
• Planetary protection (PP) requires the avoidance of “harmful contamination” of
the target body, during the “period of biological exploration”.
• Since the early 1960s, consensus international policy (COSPAR) has provided
constraints for the probability of contamination at the 1x10-4 per mission level.
Planetary Protection
16
• Based on available knowledge of Mars, the Viking landers were system sterilized to adhere to NASA’s policy, adopted from COSPAR.
• Knowledge gained by Viking then allowed relaxation of the PP requirements to the present MSL-era “spore” based approach.
Viking
Terminal
Sterilization
• Based on available knowledge of Europa, Clipper needs to be sterilized to
TBD level to achieve the same 1x10-4 probability of contamination.
• Specifically, anticipated as a Planetary Protection Category III mission, Clipper would have
the principal planetary protection requirement of demonstrating a <1x10-4 probability of
contaminating a sub-surface Europan ocean.
For Planetary Protection, Europa is today where Viking was in the 1970’s
Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
Present Coverage in Plumes Region 13F7-A21 Trajectory
3/4/14 17 Pre-Decisional — For Planning and Discussion Purposes Only
Plume High Phase Opportunities 150° ≤ f ≤ 180°
3/4/14 18 Pre-Decisional — For Planning and Discussion Purposes Only
Sun Direction 315° – 45°
45° – 135°
135° – 225°
225° – 315°
Europa True Anomaly
• Many Clipper orbits afford
excellent geometry for
observations of putative
plumes
• This permits an effective
fly-through and sampling
campaign to be designed
once Clipper is at Jupiter
Achieving Decadal Science
“The first step in understanding the potential of the outer solar
system as an abode for life is a Europa mission with the goal of
• Confirming the presence of an interior ocean,
• Characterizing the satellite’s ice shell, and
• Enabling understanding of its geologic history”
Composition Geology Ice Shell Ocean
– The Planetary Decadal Survey, 2011
19 Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
“We continue to support the Europa Clipper mission as a scientifically
compelling, technologically feasible and fiscally responsible approach to
exploration of Europa. The Europa Clipper mission meets the requirements of
the 2013-2022 Decadal Survey: it will accomplish flagship-worthy science by
investigating Europa and its subsurface ocean, a potential habitable zone.”
– Outer Planets Assessment Group (OPAG), 2013
Achieving Decadal Science
“Flagship-class missions historically
have a greatly enhanced science
return compared to smaller
missions—the whole is greater
than the sum of the parts—so the
higher cost of a flagship mission
compared to a New Frontiers-class
mission is well justified. Europa
remains the highest priority for
satellite exploration, and a Europa
mission deserves sufficient
resources to realize its
phenomenal scientific potential.
Therefore, a Europa mission should
take precedence over smaller
missions to outer solar system
targets during the next decade.” The Planetary Decadal Survey
20 Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
Backup
3/4/14 21
Radiation Modeling: GIRE2
22
1.40E+05
3.32E+05
3.64E+05
5.64E+05
9.71E+05
1.07E+06
1.35E+06
1.48E+06
1.63E+06
1.70E+06
2.08E+06
2.00E+05
4.60E+05
5.05E+05
7.71E+05
1.31E+06
1.44E+06
1.84E+06
2.01E+06
2.22E+06
2.31E+06
2.82E+06
1.50E+05
0.0E+00
5.0E+05
1.0E+06
1.5E+06
2.0E+06
2.5E+06
3.0E+06
11/9/
27
2/17/28
5/27/28
9/4/2
8
12/13/2
8
3/23/29
7/1/2
9
10/9/
29
1/17/30
4/27/30
8/5/30
11/13
/30
2/21/31
6/1/3
1
9/9/3
1
12/18/3
1
3/27/32
TOTA
LDOSE
13-F7GIRE(100milAl,SphericalShell)
13-F7GIRE2(100milAl,SphericalShell)
13-F7GIRE2(BehindVault)
Switch-flip
COT-1 N
on-R
esonant
Tra
nsfe
r
Petal Rotation
COT-2
COT-4 COT-3
Pum
p D
ow
n,
Cra
nk U
p
Pum
p U
p,
Avoid
Sola
r C
onju
nction
Non-R
esonant
Tra
nsfe
r
Transfer to Europa Science
Pre-Decisional — For Planning and Discussion Purposes Only
Previous modeling used
GIRE1. GIRE2 model
extends out past L=16 to
L=25 and addresses several
concerns with the original
Divine/GIRE model.
3/4/14
11F5-A21 / 13F7-A21 Comparison Quick Look
Pedal Plot Comparison
SWIRS Coverage Comparison
Radiation Dose Comparison
8.92E+04
4.87E+05
6.61E+05
1.34E+06
1.86E+06
2.06E+06
7.23E+04
3.04E+05
5.03E+05
9.20E+05
1.30E+06
1.44E+06
1.66E+06
2.08E+06
0.00E+00
2.50E+05
5.00E+05
7.50E+05
1.00E+06
1.25E+06
1.50E+06
1.75E+06
2.00E+06
2.25E+06
1
17
33
49
65
81
97
113
129
145
161
177
193
209
225
241
257
273
289
305
321
337
353
369
385
401
417
433
449
465
481
497
513
529
545
561
577
593
609
625
641
657
673
689
705
721
737
753
769
785
801
817
833
849
865
881
897
913
929
945
961
977
993
1009
1025
1041
1057
1073
1089
1105
1121
1137
1153
1169
1185
1201
1217
1233
1249
1265
1281
TID(rads)
Time-of-FlightFrom(1dayincrements)
11F5 13F7
Gravity Science
Performance
Pre-Decis ional — For Planning and Discussion Purposes Only 3/4/14 23
11F5 13F7 11F5 13F7
11F5
13F7
Gravity Science Concept
• Gravity Science measurement
made concurrently with other flyby
observations
• Two-way, coherent, carrier only
radio link to Earth through medium
gain fan beam antennas
• Nadir spacecraft pointing requires
sequenced switching through
several antennas to maintain lock
with Earth
• Doppler measurement made by
Earth-based DSN Radio Science
Receiver
24
Forward
Fanbeam -Y
Fanbeam
-Z
Fanbeam
3/4/14 Pre-Decisional — For Planning and Discussion Purposes Only
Gravity Science Performance Model Simulation of k2 Uncertainty Through the Mission
• 2-fanbeam configuration; No ESA tracking
• Baseline: 3-element fanbeam; No ESA tracking
• 2-fanbeam configuration plus ESA tracking for
(E18, E22) provides ~ 20% margin
• Best 3-fanbeam configuration plus ESA
tracking for (E18, E22) provides ~ 36% margin
Baseline
Pre-Decisional — For Planning and Discussion Purposes Only 25 3/4/14
Requirement: k2 uncertainty < 0.05
New Orbital Tour Design Baseline 13F7-A21
• Last OPAG meeting, introduced a new tour design under
consideration that improved flyby coverage and lighting
– Utilizes a more TID effective strategy (at the cost of time-of-flight) to
reach the Europa sub-Jovian hemisphere science phase
– Enables more Europa flybys, 45 (over 3.5 yr) vs. 32 (over 2.5 yr), for
approximately the same TID
• 37 flybys of 100 km or less
• Nine Callisto and four Ganymede flybys used for Europa positioning
– Tour developed for November 2021 Atlas launch
• In principle, similar tour can be created for any opportunity
– Team working updated tour, which decreases solar eclipse durations
• 13F7-A21 is now the current Pre-Project baseline tour
– Project Science is continuing to evaluate the tour
– Started to consider implications of the Europa plume discovery
3/4/14 26 Pre-Decisional — For Planning and Discussion Purposes Only
Solar Power Feasibility Review August 2, 2013
• Review covered all mission aspects (not just the solar array)
– Chaired by the NASA power system Technical Fellow
– External panel with expertise across all spacecraft system disciplines
• Review board major findings:
– Solar power is feasible for the mission however there are risks to retire, all within
manageable engineering
– No new technology needed
– Numerous mission risks identified and considered (by the Project team)
• Primary risk is cold temperature combined with radiation
– The project risk management and mitigation plan is valid and realizable
• Actions since review:
– Board Chair briefed the NASA Planetary Science Division
– Continue to baseline MMRTG
– Initiated a risk reduction task of combined radiation and cold temperature testing
• Expect final results late next year
– Removed ASRG from option space
• Revisit MMRTG vs solar power trade next year
3/4/14 27 Pre-Decisional — For Planning and Discussion Purposes Only
Major Risk Reduction Tasks
3/4/14 28
• Approximately 25% of project funding is being directed to risk
reduction activities
• Radiation
– CFC-11 testing
– Materials testing
– Attitude determination
sensor evaluation
– Pressure transducer
development
– EEE parts testing
– Radiation and plasma
model update
• Planetary Protection
– Vapor phase hydrogen peroxide
sterilization evaluation
– dry heat microbial reduction
implementation approaches
• Solar Feasibility
– Solar array cold
survivability testing
– Solar array radiation testing and
electrostatic discharge evaluation
• Mission
– High energy density battery cell characterization
– Time trigger Ethernet characterization
– Autonomous navigation
Pre-Decisional — For Planning and Discussion Purposes Only
MMRTG vs. Solar Power Vehicle Comparison
MMRTG Solar Power Solar Power
Compatibility
Dual-Mode
Propulsion
Bi-propulsion Lower freezing
temperature of bi-
propellant reduces
Solar array and
battery mass
Magnetometer
separate
boom
Magnetometer
on end of
solar array
Location on array
reduces spacecraft
mass
Langmuir
probe on
MMRTG heat
shield
Langmuir
probe at end
of solar arrays
Location required to
provide Langmuir
probe visibility
45% mass
margin
40% mass
margin
Solar array and
battery heavier than
MMRTGs
Pre-Decisional — For Planning and Discussion Purposes Only 29 3/4/14
Tracking Changes Between Two Power
Sources
“Orbit-in-the-Life” of Europa Clipper
3/4/14 30 Pre-Decisional — For Planning and Discussion Purposes Only
Example shown for a 14-day
transfer, which is the shortest
duration transfer between
subsequent Europa flybys for
the current tour (13F7).
Representative Europa Flyby
31
• Repetitive, Simple Science
Operations Plan
• Instrument performance
parameters
• Instrument on / off times
• Compression ratios
• Designed for simultaneous
instrument operations
• Instrument deck remains
nadir fixed below 28,000 km
• Collected data returned
during next 30 days
• Prioritized
• Often much sooner
• Another flyby may occur
before full data return
3/4/14 Pre-Decisional — For Planning and Discussion Purposes Only
Mission Plan
Launch 21 Nov 2021
Jupiter Arrival 4 Apr 2028
Science Tour 45 Europa Flybys
Primary Mission End Oct 2031
Science
Objective Description
Ice Shell &
Ocean Characterize the ice shell, subsurface water & surface-ice-ocean interface.
Composition Understand the habitability of Europa's ocean through composition and
chemistry.
Geology Understand the formation of surface features, including sites of recent or
current activity, and characterize high science interest localities.
Recon Characterize Safe and Scientifically Compelling Sites for a Lander Mission
to Europa
Model Payload
Acronym Instrument
Flo
or
IPR Ice Penetrating Radar
SWIRS Shortwave Infrared
Spectrometer
TI Topographical Imager
NMS Neutral Mass
Spectrometer
Site
Se
lection
Recon Reconnaissance
Camera
Thermal Thermal Imager
Ba
se
line
LP Langmuir Probe
GS Gravity Science
Europa Clipper Concept Overview
32 Pre-Decisional — For Planning and Discussion Purposes Only 3/4/14
Notional Instrument Locations
Configuration meets
all Field-of-view
requirements for
notional instruments
Pre-Decisional — For Planning and Discussion Purposes Only
Neutral Mass
Spectrometer (NMS)
Langmuir Probes (x2)
Gravity Science
Fanbeam Antennae (x2)
Ice Penetrating Radar
Antennae
Magnetometers (x2)
Shortwave Infrared Spectrometer
Reconnaissance Camera
Thermal Imager
Topographic Camera
33 3/4/14
Notional Payload Accommodations
• Multiple standard interface types: TTE,
SpaceWire, ICC/ITC, UART, 1553
– Rate buffering required if payload data
rate is above these standards
• Bulk data storage provided: 128 Gb
• Compression trade study in progress
• Telemetry formatting provided by spacecraft
• Synchronizing and time stamping provided
by spacecraft
• Remote electronics hosted in radiation vault
(≤150 krad) on thermal loop
• For nadir mounted instruments: thermal loop
available to source/sink heat
Accommodations being defined for
possible AO supporting documents
Interface Name PHY Type Data Rate
(max.) Data Rate (25% max. allocation)
1553 Shared common physical interface
800 Kbps 200 Kbps
ICC/ITC P2P/LVDS 8 Mbps 2 Mbps
UART P2P/422/LVDS
1 Mbps 250 Kbps
TTE P2P/802.3 1 Gbps 250 Mbps
SpaceWire P2P/LVDS 400 Mbps 100 Mbps
Radiation Vault for
remote instrument
electronics
Instrument Deck on
Nadir pointing side Pre-Decisional — For Planning and Discussion Purposes Only
34 3/4/14
SLS Assessment Status
35 3/4/14
Atlas V 551
2021 VEEGA Trajectory
(6.37 year flight time)
SLS
2022 Direct-to-Jupiter Trajectory
(2.73 year flight time)
* Launch dates shown are the optimal launch dates, not the open of a launch period
Launch (14-Jun-2022)
JOI (4-Mar-2025)
Jupiter
Orbit
Launch
(21-Nov-2021) EGA-2
(24-Oct-2025)
EGA-1
(24-Oct-2023)
JOI
(4-Apr-2028)
VGA
(14-May-2022)
Baseline Trajectory
Jupiter
Orbit
• SLS would enable a shorter time of flight,
eliminates two Earth flybys and thermal
considerations for a Venus gravity assist
• Current earliest launch opportunity is
with SLS Block-1 vehicle in June of 2022
– Time of flight to Jupiter is 2.7 years
– Mass capability 4,800 kg
• Same as Atlas launch in November
2021 with Venus-Earth-Earth gravity
assist trajectory (which has 6.5 yr
time of flight)
• Tour after Jupiter orbit insertion is the
same for both vehicles
• The project will maintain dual launch
capability through CDR
Team continues to work with Marshall to assess this
option
Pre-Decisional — For Planning and Discussion Purposes Only