Louise Prockter Applied Physics Laboratory, Johns Hopkins University Barry Goldstein Jet Propulsion Laboratory, California Institute of Technology

Transcription

1 EUROPA Louise Prockter Applied Physics Laboratory, Johns Hopkins University Barry Goldstein Jet Propulsion Laboratory, California Institute of Technology Copyright 2016 California Institute of Technology. Government sponsorship acknowledged

2 Europa s youthful surface A world of rock, ice, and water approximately the size of Earth s moon Very few impact craters suggest that Europa has one of the youngest surfaces in the solar system (~60 Ma) Suggests recent resurfacing = likely an active world

3 Global tectonic activity Surface is criss-crossed by bands and ridges in all orientations, and at all scales Driven by tidal squeezing causes cracking on the surface May have plate tectonics system 50 km 5 km

4 Extensive cryovolcanism Evidence of liquid water volcanism Surface is broken into plates, matrix Energy from tidal squeezing likely causes melting and convection in the ice 50 km 10 km

5 Possible plumes of water Recent Hubble observations of Hydrogen and Oxygen ions concentrated near Europa s south pole Interpreted as plumes of water vapor ~200 km high Enceladus

6 Surface chemistry of salts and acid Surface is bombarded by charged particles from Jupiter s magnetosphere Interaction of these particles with the surface leads to interesting chemistry 20 km

7 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]

8 Magnetometer evidence indicates the presence of a ~100 km thick subsurface liquid water ocean at Europa Thickness of the overlying ice shell is the subject of intense debate estimates range from a few km to ~30 km

9 Water World All Earth s water 2x Earth s water Earth: Known life Mars: Past conditions for life Europa: Present conditions for life?

10 Europa: Ingredients for Life? Water More than 2x all of Earth s oceans Essential elements From formation and impacts Chemical energy Potentially from above and below Stability Variable, but simmering for 4 By A Europa mission would verify Black key habitability smoker on Earth s hypotheses ocean floor

11 Europa mission concept history Because of (its) ocean s potential suitability for life, Europa is one of the most important targets in all of planetary science Planetary Decadal Survey Europa mission concepts have been studied by NASA for more than a decade The 2011 NRC Decadal Survey stated that the $4.7B Jupiter Europa Orbiter mission concept had extremely high science value but was unaffordable, and requested a descoped option Subsequent studies by a joint JPL-APL team resulted in a multiple-flyby concept (the Europa Clipper) that retains high science value at significantly reduced cost The Europa Multiple-Flyby mission was approved by NASA in June, 2015 and is currently in Phase A

12 Jupiter s Radiation Belts Europa

13 Innovative Mission Concept Stereo Camera (alt km) Radiation Accumulation

14 Galileo Flybys Of Europa Total of 11 Galileo Flybys of Europa Instrumentation 1970 s Technology Spacecraft Trajectory 25 km r alt 50 km 50 km < r alt 400 km 400 km < r alt 1000 km 1000 km < r alt 4000 km

15 Galileo Flybys Under 1,000 km Only 4 Galileo Flybys under 1,000 km 692 km, 586 km, 351 km & 201 km Spacecraft Trajectory 25 km r alt 50 km 50 km < r alt 400 km 400 km < r alt 1000 km 1000 km < r alt 4000 km

16 Present Coverage in Potential Plume Region 13F7-A21 Trajectory Above 1,000 km km to 750 km 6 80 km to 100 km 9 50 km km 10 Spacecraft Trajectory 25 km r alt 50 km 50 km < r alt 400 km 400 km < r alt 1000 km 1000 km < r alt 4000 km

17 EVEEGA Interplanetary Trajectory EELV (ATLAS/Delta-IV/Falcon) 21 Day launch period opens May 2022 Earth/Venus/Earth/Earth Gravity Assist Arrive Jovian System January, 2030 (7.5 Years)

18 Direct-to-Jupiter Trajectory & Jovian Tour SLS Launch Option SLS 2022 Direct-to-Jupiter Trajectory (2.73 year flight time) 21 Day launch period opens June 2022 Arrive Jovian System March, 2025 (2.7 Years) Tour after Jupiter orbit insertion is the same for both vehicles The project will maintain dual launch capability through CDR

19 NASA-Selected Europa Instruments Radiation Science Working Group WG Lead: Chris Paranicas JHU-APL MASPEX Mass Spectrometer PI: J. Hunter Waite SwRI, San Antonio SUDA Dust Analyzer PI: Sascha Kempf Univ. Colorado, Boulder ICEMAG Magnetometer PI: Carol Raymond JPL-Caltech PIMS Faraday Cups PI: Joe Westlake JHU-APL Europa-UVS UV Spectrograph P!: Kurt Retherford SwRI, San Antonio EIS Narrow-Angle Camera + Wide-Angle Camera PI: Zibi Turtle JHU-APL MISE IR Spectrometer PI: Diana Blaney JPL-Caltech E-THEMIS Thermal Imager PI: Phil Christensen Arizona State Univ. REASON Ice-Penetrating Radar PI: Don Blankenship Univ. Texas Inst. Geophys. Gravity Science Working Group WG Lead: Sean Solomon Lamont-Doherty Remote Sensing In Situ

20 Proposed Flight System Configuration 5.0 m ICEMAG Boom 16m REASON HF Antenna (2x) Solar Array Panels (8x) 2.2m x 4.1m each ~72 m 2 area RAM Pointed Instruments Nadir Pointed Instruments S/C Height 4.6 m Solar Array Width 22.3m REASON VHF Antennas (4x)

21 Mission Enhancements? Several options for mission enhancements have been under study Plume Free Flyers Landed Element Gravity Science Working Group (GSWG) Direction received in February Keep Clipper on 2022 launch path Extend lander study as a Pre-Project Only as a separate S/C launched either co-manifest (SLS only possible LV) or separate launch Evaluate longer time on surface, greater payload capacity Direction received in March Plume Free Flyers removed from consideration In response to recommendation from GSWG, Project evaluating the accommodation impacts of a Laser Altimeter 21

22 Top Level Schedule (UPDATED) (June 2022 Launch) 22

23 Backup

24 Outer Planet S/C Galileo Launch Mass: 2,562 kg Cassini Launch Mass: 5,655 kg Europa Multi-Flyby Launch Mass: 5,100 kg 24

25 Lander Concept Highlights Spacecraft physically decoupled from Clipper Enter Jovian system and park in a radiation safe orbit awaiting reconnaissance from Clipper to decide where to target landing Spacecraft components: Carrier/Orbit Stage Delivers system to Jovian system and eventually targets lander stack (everything bellow) Provides relay capability (Clipper can be backup) to earth De-orbit Module Decelerates lander to capture a Europa descent trajectory Descent Module Slows down lander, terminal descent to Europa Lander Science!!! 25

26 Top-Level Mission Event Sequence 26

27 Carrier / Orbit Stage Concept Lander Stack

28 Lander Stack System Concept Descent Stage Lander De-orbit Stage Lander Stack at Integration Lander Stack Exploded View

29 Lander Descent and Surface Concepts 1 - Descent Configuration 2 Sky Crane Configuration 3 - Landed Deployed

30 Lander Surface Configuration Gimbaled HGA Vault Discarded Bridle Release Battery Panels Pan Cam GCMS Microscope Raman Sampling System 30

31 Sampling System Concept with Saw Type Device Stowed Arm Configuration Sample Capture Cradle Surface Excavation Counter Rotating Saw blades excavate as chippers or brushes Sample Delivery 31

32 Model Payload (Total Mass: 25/35 kg MEV) Centerpiece Instruments for Astrobiology GCMS Raman Auxiliary Instruments Context LanderCams (x2), 0.5 kg each CBE Microscopic SampleCam, 0.5 kg CBE Baseline Instrument (not included in Threshold) 3-axis Geophone, 0.8 kg 32

33 Current Jupiter Delivery Strategy Baseline Launch Vehicle: SLS Block-1 Transfer: Earth-Jupiter Direct Time-of-flight: yrs. Backup Launch Vehicle: Atlas V 551 or Delta IV Heavy Transfer: EVEEGA Time-of-flight: 7.4 yrs. SLS 2022 Direct (2.72 years) Jupiter Orbit JOI (5-Mar-2025) Launch (6-Jun-2022) JOI (15-Jan-2030) VGA (26-Nov-2023) Jupiter Orbit Launch (17-Jun-2022) EGA-3 (22-Oct-2026) EGA-2 (21-Oct-2024) EGA-1 (17-Jun-2023) Mass Margin 35% Launch 33% Launch Atlas V % 30% Mass Margin 2022 Launch 2023 Launch Delta IV Heavy** 65% 66% ** IF fully utilize L.V. capability 33

34 Modified Jupiter Delivery Strategy [With 250 kg ESA/NASA Asset Mass Holdback] BASELINE Launch Vehicle: SLS Block-1 Transfer: Earth-Jupiter Direct Time-of-flight: yrs. Backup Launch Vehicle: Delta IV Heavy Transfer: v/ega Time-of-flight: 4.7 yrs. SLS 2022 Direct (2.72 years) JOI (5-Mar-2025) Jupiter Orbit Launch (17-Jun-2022) EGA-1 (7-Aug-2023) Jupiter Orbit Launch (6-Jun-2022) JOI DSM (24-May-2027) (21-Oct-2024) Mass Margin 27% Launch 24% Launch Mass Margin 26% Launch 26% Launch 34

35 Modified Jupiter Delivery Strategy [Without ESA/NASA Asset Mass Holdback] Baseline Launch Vehicle: SLS Block-1 Transfer: Earth-Jupiter Direct Time-of-flight: yrs. Backup Launch Vehicle: Delta IV Heavy Transfer: v/ega Time-of-flight: 4.7 yrs. SLS 2022 Direct (2.72 years) JOI (5-Mar-2025) Jupiter Orbit Launch (17-Jun-2022) EGA-1 (7-Aug-2023) Jupiter Orbit Launch (6-Jun-2022) JOI DSM (24-May-2027) (21-Oct-2024) Mass Margin 35% Launch 33% Launch Mass Margin 34% Launch 34% Launch To be verified 35

36 Modified Jupiter Delivery Strategy [With Laser Altimeter?] Baseline Launch Vehicle: SLS Block-1 Transfer: Earth-Jupiter Direct Time-of-flight: yrs. Backup Launch Vehicle: Delta IV Heavy Transfer: v/ega Time-of-flight: 4.7 yrs. SLS 2022 Direct (2.72 years) JOI (5-Mar-2025) Jupiter Orbit Launch (17-Jun-2022) EGA-1 (7-Aug-2023) Jupiter Orbit Launch (6-Jun-2022) JOI DSM (24-May-2027) (21-Oct-2024) Mass Margin 35% Launch 33% Launch Mass Margin 34% Launch 34% Launch To be verified 36

37 Orbit-in-the-Life of Europa Clipper Example shown for a 14-day transfer, which is the shortest duration transfer between subsequent Europa flybys for the current tour (13F7).

38 Europa Pedal- Jovian Orbit Flyby Dose Rate* (rad/sec) Cleanup maneuver DCO (2 days before maneuver) Cleanup Maneuver (3 days after the flyby) Start Backup Approach Maneuver (2 days before the flyby) Targeting Maneuver DCO (2 days before the maneuver) Approach Maneuver (3 days before the flyby) Targeting Maneuver (near apoapsis) Approach Maneuver DCO (2 days before maneuver) Key: DCO: Data Cutoff *Si behind 100 mil Al, spherical shell (GIRE2)

39 Pump Up, Avoid Solar Conjunction Non-Resonant Transfer Non-Resonant Transfer Pump Down, Crank Up Radiation Modeling: GIRE2 3.0E F7 GIRE (100 mil Al, Spherical Shell) 13-F7 GIRE2 (100 mil Al, Spherical Shell) Switchflip 2.82E F7 GIRE2 (Behind Vault) 2.5E E+06 Previous modeling used GIRE1. GIRE2 model extends out past L=16 to L=25 and addresses several concerns with the original Divine/GIRE model. Petal Rotation 1.84E E E E E+06 TOTAL DOSE 1.5E+06 COT-1 COT E E E E E E E E E+05 Transfer to Europa Science 7.71E E E E E E E E E+05 COT-3 COT E E+00 11/9/27 2/17/28 5/27/28 9/4/28 12/13/28 3/23/29 7/1/29 10/9/29 1/17/30 4/27/30 8/5/30 11/13/30 2/21/31 6/1/31 9/9/31 12/18/31 3/27/32 3/4/14