Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.cosmos.ru/conf/2009elw/presentations/presentations_pdf/session1/clark_ELW.pdf Äàòà èçìåíåíèÿ: Mon Mar 2 19:58:54 2009 Äàòà èíäåêñèðîâàíèÿ: Mon Apr 6 23:50:43 2009 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ion drive

Current Status of the EJSM Jupiter Europa Orbiter Flagship Mission Design
Presentation to the International workshop: "Europa lander: science goals and experiments" 2/09
Presented by:

Karla B. Clark
EJSM­JEO Study Manager
Jet Propulsion Laboratory California Institute of Technology

Jupiter Europa Orbiter
The NASA Element of the Europa Jupiter System Mission


· NASA & ESA share mission leadership

EJSM Baseline Mission Overview
Jupiter Europa Orbiter (JEO): NASA-led mission element Jupiter Ganymede Orbiter (JGO): ESA-led mission element Nominal Launch: 2020 Jovian system tour phase: 2­3 years Moon orbital phase: 6­12 months End of Prime Missions: 2029

· Two independently launched and operated flight systems with complementary payloads
­

­

· Mission Timeline
­ ­ ­ ­

· ~10­11 Instruments on each flight system, including Radio Science
2/8/08
Predecisional, For Planning Purposes Only

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JGO Baseline Mission Overview
· · · · · ESA-led portion of EJSM Objectives: Jupiter System, Callisto, Ganymede Launch vehicle: Arianne 5 Power source: Solar Arrays Mission timeline:
­ Launch: 2020
· Uses 6-year Venus-Earth-Earth gravity assist trajectory

­ Jovian system tour phase: ~28 months
· Multiple satellite flybys
­ 9 Ganymede ­ 21 Callisto (19 close flybys)

Wide Angle and Medium Resolution Camera V/NIR Imaging Spectrometer EUV/FUV Imaging Spectrometer Ka-band transponder Ultra Stable Oscillator Magnetometer Radar Sounder Micro Laser Altimeter Thermal IR Mapper Sub-millimeter wave sounder Plasma Package

­ Ganymede orbital phase: 260 days ­ End of prime mission: 2029 ­ Spacecraft final disposition: Ganymede surface impact

· Radiation: ~85 krad behind 320 mils of Al (requirement to keep it below 100 krad)

2/8/08

Predecisional, For Planning Purposes Only

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JGO Science
· Key Science Objectives
­ In depth post-Galileo exploration of the Jupiter system, synergistically with JEO
· En route to Callisto and Ganymede

­ In-depth study and full mapping of Callisto
· Multiple flybys using a resonant orbit

­ Detailed orbital study of Ganymede
· Two successive dedicated moon orbits (elliptical first, then circular)

· A major step forward in our understanding of the two "icy" Galilean satellites, Ganymede and Callisto:
­ ­ ­ ­ ­ Ocean detection/characterisation State of internal differentiation Global surface mapping: morphology and chemistry Comprehensive study of Ganymede's magnetism Relations between thermal history, geology, oceans and the Laplace resonance
Predecisional, For Planning Purposes Only

2/8/08

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JEO Baseline Mission Overview
· · · · · NASA-led portion of EJSM extensively studied in 2007­2008 Objectives: Jupiter System, Europa Launch vehicle: Atlas V 551 Power source: 5 MMRTG or 5 ASRG Mission timeline:
­ Launch: 2018 to 2022, nominally 2020
· Uses 6-year Venus-Earth-Earth gravity assist trajectory

­ Jovian system tour phase: 30 months
· Multiple satellite flybys: 4 Io, 6 Ganymede, 6 Europa, and 9 Callisto

­ Europa orbital phase: 9 months ­ End of prime mission: 2029 ­ Spacecraft final disposition: Europa surface impact

· 11 Instruments, including radio science · Radiation dose: 2.9 Mrad (behind 100 mils of Al)
­ Handled using a combination of rad-hard parts and tailored component shielding ­ Key rad-hard parts are available, with the required heritage ­ Team is developing and providing design information and approved parts list for prospective suppliers of components, including instruments
2/8/08
Predecisional, For Planning Purposes Only

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JEO Goal: Explore Europa to Investigate Its Habitability
Objectives:
· Ice Shell · Chemistry and Composition · Geology · Jupiter System
­ Satellite surfaces and interiors ­ Satellite atmospheres ­ Plasma and magnetospheres ­ Jupiter atmosphere ­ Rings

· Ocean and Interior

Europa is the archetype of icy world habitability
2/8/08
Predecisional, For Planning Purposes Only

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JEO Model Payload
JEO Instrument
Radio Science Laser Altimeter Ice Penetrating Radar VIS-IR Spectrometer UV Spectrometer Ion & Neutral Mass Spectrometer Thermal Instrument Narrow-Angle Camera Camera Package Magnetometer Particle and Plasma Instrument

Similar Instruments
New Horizons USO, Cassini KaT MESSENGER MLA, NEAR NLR MRO SHARAD, Mars Express MARSIS MRO CRISM, Chandrayaan MMM Cassini UVIS, New Horizons Alice Rosetta ROSINA RTOF MRO MCS, LRO Diviner New Horizons LORRI, LRO LROC MRO MARCI, MESSENGER MDIS MESSENGER MAG, Galileo MAG New Horizons PEPSSI, Deep Space 1 PEPE

2/8/08

Predecisional, For Planning Purposes Only

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JEO Baseline Flight System
· · · · · · · · Three-axis stabilized with instrument deck for nadir pointing Articulated HGA for simultaneous downlink during science observations Data rate of 150 kbps to DSN 34m antenna on Ka-band Performs 2260 m/s V with 2646 kg of propellant Five MMRTGs would provide 540 W (EOM) with batteries for peak modes Rad-hardened electronics with shielding to survive 2.9 Mrad (behind 100 mil Al) environment 9-year lifetime Healthy mass and power margins (43%, >33% respectively)

Artist Rendering

JEO incorporates minor modifications to a strong EE2007 design
2/8/08
Predecisional, For Planning Purposes Only

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JEO Flight System Block Diagram
C&DH*
Computer Chassis (2) Computer Chassis (2) CEPCU CEPCU MREU MREU Custom JEO Card Custom JEO Card
cPCI Backplane cPCI Backplane

Telecom
SDST (2) SDST (2) X/Ka-band X/Ka-band Exciter Exciter X-band X-band Exciter Exciter X-band X-band Receiver Receiver HYB X X 44 KaT T 25W RF KaTWTA Band TWTA Ka-band (2) 25W RF TWTA X-band X-band TWTA (2) CTS WTS USO X-Band MGA WTS Ka Diplexer (2) Diplexer WTS (2) X Diplexer (2) Diplexer X-Band LGA (2) 3m Ka/ X HGA WTS HYB

*Note: All C&DH interfaces are cross-strapped.

AACS
Sun Acquisition Wheel lDrive Whee Drive Detectors (3) Electronics (4) Electronics (4) 4-Channel Gimbal l 2-Channel Gimba Drive Electronics ((3) Drive Electronics 2)
U/L, D/L

HYB

Filter

MTIF MTIF BAE RAD BAE RAD 750 (2 slot width) 750 (2 slot width) SIRU (1) Star Trackers Wheel Drive (2) Electronics (4)

TELECOM ENCLOSURES BEHIND HGA

Hybrid SSR: 1Gb CRAM 16 Gb SDRAM Science Memory

Mechanical & Thermal
25 Nms RWA (4) w/ electronics 10m Magnetometer Boom Shunt Radiator MLI Temp Sensors & Heaters

Main Engine Gimbal

Linear Separation HGA Gimbal RHUs (20) Louvers Assembly

Atlas V 551
LV Adapter (LV provides)
To MTIF Card in C&DH

3m HGA Boom Variable RHUs (24)

Rad Monitoring
Rad Monitoring 6U Electronics Card (Physically
in C&DH Chassis)

Sensor 1 Sensor 3 Sensor 2

Low-Rate Instruments Ion and Neutral Mass Spectrometer (INMS)

Power

Waste Heat MMRTG MMRTG MMRTG (5) MMRTG MMRTG (5) ) (5 (5) (5)

Power Distribution Unit Power Bus Controller Remote Remote Engineeering Engin ering Unitit(22) Un ( ) Power Power Connditioning Co ditioning Unitit(22) Un ( ) Prop Drive Prop Drive Prop Drive Prop D 4) Electronicsrive Electronics((4)) Electronics (4 Electronics (4) Pyro Driver Pyro Driver PyrroDrivver Pyo o (6) er Pyr (ri CaPyssDDriver rd 6 CardroDriver Cardss(())) Card s6 6) 6 Card s((6) Card Power Switch Power Switch PowerrSwitch Powe (8) itch PowerSwitch CardserSwitch PowerSw Cards ((Switch ) Pow s (8) Cards 8Switch Power () Card s 88) Card s (8) Card s (8) Card s (8) Card

T-0 Umbilical

Propulsion
GHe Pressure Transducers (10) GHe

Model Payload
High-Rate Instruments Wide Angle & Medium Angle Cameras (WAC + MAC)

Ultraviolet Spectrometer (UVS) Power Assembly Laser Altimeter (LA) Shunt Limiter FETs RPS Protection Diodes Balanced Bus Grounding Hardware Pyro and Prop Enable Relays 12 A-Hr LiIon Batteries (2) Battery Control FET Board

Ox Tank

Fuel Tank

Narrow Angle Camera (NAC)

Thermal Instrument (TI)

Lightning Suppression Assembly

L

IR Spectrometer (VIRIS)

Particle and Plasma Instrument (PPI)

To S/C Loads

16 (8 coupled clusters) 4.5 N ACS Thrusters

Ice Penetrating Radar (IPR)

Dual Magnetometer (MAG)

2/8/08

Predecisional, For Planning Purposes Only

Gimbaled 890 N HiPAT Main Engine

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JEO Mass Summary
JEO Baseline Mass Equipment List
Flight System Mass, kg
CBE Payload Model Payload Payload Radiation Shielding Spacecraft Power (w/o RPSs) C&DH Telecom Structures & Mechanisms Thermal Propulsion AACS Cabling Radiation Monitoring System RPS System Spacecraft Radiation Shielding Flight System Total Dry Additional System Margin to achieve study req. Flight System Total Dry with Required Margin Propellant Flight System Total Wet LV Adapter with required margin Flight System Launch Mass Wet Atlas V 551 Capability for 2020 VEEGA Additional Margin System Margin (33% required per study guidelines) 163 106 57 1208 55 34 56 320 68 157 69 83 8 226 132 1371 1371 1371 1453 Cont. 30% 30% 30% 24% 30% 17% 27% 31% 30% 28% 33% 30% 30% 0% 30% 25% 41% CBE+Cont. 211 137 74 1498 72 40 70 420 88 201 91 108 10 226 172 1709 226 1935 2646 4581 123 4704 5040 336 43%

Payload and Shielding

Calculating Dry Mass Margin per Study Guidelines:
Dry Mass Allocation (MPRV) = LV Capability ­ Prop­RTG Mass* = 5040 ­ 2646 ­ 226 = 2168 kg

5 MMRTGs S/C Radiation Shielding for 2.9 Mrad Delta V of 2260 m/s Very Healthy Margins

Dry Mass CBE (PRV) = S/C CBE + LV Adapt­RTG Mass* = 1371 + 82 ­ 266 = 1227 Dry Mass Margin = (MPRV ­ PRV)/MPRV = (2168 ­ 1227)/2168 = 43%
*Note: The MMRTG mass is considered a Not-To-Exceed Mass, and is therefore excluded from the margin calculations, per HQ direction.

JEO's design is robust to future changes due to large mass margins
2/8/08
Predecisional, For Planning Purposes Only

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Jupiter System Science
· · Jupiter and Io monitoring, atmospheres, magnetospheres, rings and small bodies Satellite science
­ Io: 3 flybys · Opportunities for imaging, IR spectroscopy, and altimetry · ­ In situ analysis of extended atmosphere with INMS at 75 km Europa: 6 flybys · Radar and altimetry characterization and calibration · Imaging at up to 10-50 m resolution, NIR 250-1250 m Ganymede: 6 flybys · Radar sounding of grooved and dark terrains · Range of lats, lons for magnetosphere sampling Callisto: 9 flybys · High-latitude flyby for gravity field determination · Ocean characterization with magnetometer · Radar for subsurface structure of ancient cratered terrain

­

­

2/8/08

Predecisional, For Planning Purposes Only

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Io Flyby Example

IoFlyb05LF.wmv

2/8/08

Predecisional, For Planning Purposes Only

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Europa Science Campaigns
JOI to EOI Jul 2028 Aug 2028 Sep 2028 Oct 2028
Observing Strategies for Europa Campaigns 1-3 · Always on: LA, MAG, PPI, TI, INMS (50%) · 2-orbit ops scenario permits power/data rate equalization: - Even orbits emphasize optical remote sensing: - Odd orbits emphasize radar sounding to locate water · Targets collected with residual data volume

Initial Europa Orbit
Altitude: 200 km Inclination: 95-100 deg (~85° N lat) Lighting: 2:30 PM LST Repeat: 4 Eurosols

Eng Assessment (6 d) 1A 1B

Europa Science Campaigns
2A 2B 3 4

After Campaign 1
Altitude: Repeat: 100 km 6 Eurosols
WAC context

MAC 80x20 km

10° x 10°

Europa Campaigns Global Framework 1-3 total 99 days 200 km altitude
(200 m/pixel WAC) 8 eurosols 28 days
2/8/08

Regional Processes 100 km altitude (100 m/pixel WAC) 12 eurosols 43 days
Predecisional, For Planning Purposes Only

IRS 10x10 km

Targeted Processes 100 km altitude 8 eurosols 28 days

IPR + LA

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Paving the Way for a Future Lander
· Best for Science - Recent material exchange with subsurface (i.e. young in age) and rich in chemistry
­ High resolution imaging, radar, IR spectroscopy, thermal imaging

· Safe for landing - Meter scale topography, heterogeneity, depth and porosity of regolith
­ High resolution imaging, laser altimetry, radar, thermal inertia ­ Fine scale processes: mass wasting, sputter erosion, sublimation, impact gardening, frost deposition
2/8/08
Predecisional, For Planning Purposes Only

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NASA Jupiter Europa Orbiter + ESA Jupiter Ganymede Orbiter · EJSM Study · International team, shared leadership · Built on previous studies · Community involvement · Scientifically rich · Well-defined, mature science · Exploration opportunities · Technology/mission design mature
EJSM is well defined and ready to go!
2/8/08
Predecisional, For Planning Purposes Only

Europa Jupiter System Mission

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