Transcription

1 Science Principal Investigator: Julie Castillo-Rogez Technology Principal Investigator: Les Johnson (MSFC) Project Manager: Leslie McNutt (MSFC) Sponsored by NASA HEOMD/Advanced Explorations Systems 1/13/2017 1

2 AES EM-1 Secondary Payload Overview Concepts selected in August 2013 MCR/SRR completed in August 2014 Design Review (SRR) completed in August In Phase C, delivery by end of CY17 Primary selection criteria: - Relevance to Space Exploration Strategic Knowledge Gaps (SKGs) - Life cycle cost - Synergistic use of previously demonstrated technologies - Optimal use of available civil servant workforce Completed a Non-Advocate Review of the Science Plan Payload NASA Centers BioSentinel ARC/JSC Lunar Flashlight JPL/MSFC Near Earth Asteroid (NEA) Scout MSFC/JPL 2 Strategic Knowledge Gaps Addressed Human health/performance in highradiation space environments Fundamental effects on biological systems of ionizing radiation in space environments Lunar resource potential Quantity and distribution of water and other volatiles in lunar cold traps Human NEA mission target identification NEA size, rotation state (rate/pole position) How to work on and interact with NEA surface NEA surface mechanical properties Mission Concept Study radiation-induced DNA damage of live organisms in cislunar space; correlate with measurements on ISS and Earth Locate ice deposits in the Moon s permanently shadowed craters Flyby/rendezvous and characterize one NEA that is representative of a potential human mission target

3 GOALS Near Earth Asteroid (NEA) Scout Characterize a NEA with an imager to address key Strategic Knowledge Gaps (SKGs) Demonstrates low cost reconnaissance capability for HEOMD (6U CubeSat) LEVERAGES: Solar sail development expertise (NanoSail-D, Solar Sail Demonstration Project, LightSail-A/B) CubeSat developments and standards (MarCO, University & Industry experience) Commonalities with other AES secondary payloads Key Technical Constraints: 6U Cubesat and ~86 m 2 single quadrant sail Target must be within ~1.0 AU distance from Earth due to telecom limitations Slow flyby (10-20 m/s) with target-relative navigation on close approach 3

4 Near Earth Asteroid ScoutSat (NEAScout) Close Proximity Science High-resolution imaging, 10 /px GSD over >30% surface SKGs: Local morphology Regolith properties NEA Reconnaissance <100 km distance at encounter 50 cm/px resolution over 80% surface SKGs: volume, global shape, spin properties, local environment JPL IntelliCam (Updated OCO-3 Context Camera) Target Reference stars For JPL Internal Use Only Target Detection and Approach: <50 cm/pix 50K km, Light source observation SKGs: Ephemeris determination and composition assessment (color) <15 cm/pix "The technical data in this document is controlled under the U.S. Export Regulations; release to foreign persons may require an export authorization." 1/13/

5 NEAScout Targets an NHAT NHATS database contains targets from 1 m to >1 km Targets accessible to NEAScout are < 50m Coordination with NEO Program Office Expectations is that ~5 new NHATS targets be found each year, with enhanced assets None of the NEO discoveries of the past 3 years worked for NEAScout Currently NEAScout has access to only one target at any given time (no target for a few launch windows) 5

6 Baseline Target: 1991 VG H=28.4±0.7 Diameter ~ 5-17 meters Albedo is unknown Position is known within ~2700 km (1-σ) but optical observation opportunity in July 17 will decrease uncertainty to a few 100s km Rotation period between a few minutes and less than 1 hr Unlikely to have a companion Unlikely to retain a dust cloud Solar radiation pressure sweeps dust on timescales of hours or day 6

7 Backup Target 2013 BS45 Credit: P. Chodas Upper bound on size based on 19 m resolution: D<80 m conservative bandwidth ~180 Hz P=100*D/B~3 minutes likely dark Feb 12, 2013 Goldstone Discovered by Spacewatch on Jan 20, 2013 Observed at Goldstone on Feb 10-13, 4.8 LD Earth-like orbit, NHATs target Radar astrometry extended Earth encounter predictability by ~155 years (J. Giorgini, p. comm.)

8 Plan for 1991 VG Recovery 1991 VG will be in sight from ~July 2017 to March 2018, H~23.5 Arecibo may be able to observe VG but with low SNR between January 16-28, 2018 Doppler uncertainties are 70 Hz on January 16, 2018, would be reduced to ~1 Hz after detection Optical observations best from Southern hemisphere 4-m telescopes ok for astrometry and lightcurves Larger telescope needed for colors Vishnu Reddy (UoA), Andy Rivkin (APL), and Paul Abell to coordinate observations Proposal will be submitted to NEOO Program Community is welcome to participate in observation campaign 8

9 Near Earth Asteroid ScoutSat (NEAScout) Mission Concept Characterize a Near Earth Asteroid with an optical instrument during a close, slow fly-by Payload Upgraded OCO-3 Context Camera Mechanical & Structures 6U CubeSat form factor <14 kg total launch mass Modular flight system concept Propulsion ~86 m 2 aluminized Kapton solar sail (based on NanoSail-D2) Avionics Radiation tolerant LEON3-F7 architecture Lithium Batteries (Sony/Panasonic) NEA Imager (JPL) Sun Sensor (BCT) Star Tracker (BCT) LGA (JPL) Rad-Tolerant Avionics (JPL) Iris V2.1 Transponder (JPL) Electrical Power System Deployable solar arrays with XTJ GaAs cells (~56 W EOL at 1 AU solar distance) 6.2 Ahr battery (3S2P Lithium Cells) V unregulated, 5 V regulated Active Mass Translator (MSFC) Reaction Wheels (4) (BCT) Telecom JPL Iris 2.1 X-band transponder, 4 W RF output power supports Doppler, ranging, and D-DOR 2 pairs of INSPIRE-heritage LGAs (Rx/Tx) Microstrip array MGA (Tx): ~1 kpbs to 34-m DSN at 0.75 AU Attitude Control System Nano star tracker, coarse sun sensors, and MEMS IMU for attitude determination 15 mnm-s (x4) reaction wheels Active mass translation system R-236fa (refrigerant gas) RCS system Boom Assembly (MSFC) Solar Panels & MGA (MMA/TBD/AntDevCo) Solar Sail (stowed) (MSFC) RCS (VACCO) 1/13/2017 9

10 Near Earth Asteroid Scout (NEAScout) 1/13/

11 1/13/

12 Science under Constrained Resources ACTIVITIES Target Reference stars Target Detection and approach with wide field imaging Ephemeris determination Target Reconnaissance with medium field imaging Shape, spin, and local environment Close Proximity Imaging Local scale morphology, terrain properties, landing site survey CHALLENGES Limited downlink (<4kbps) Large target position uncertainty Limited downlink (<1-4kbps) Short flyby time (<60 min.) Uncertain environment Limited downlink (<1-4kbps) Short time at closest approach (<2 min.) APPROACH Capture position ellipse in one FOV Image co-adding subwindowing Lossless Compression Thumbnails, triage, lossless compression, subwindowing Autonomous target pointing (center of brightness)

13 Summary: Contribution to NEA SKGs First imaging and characterization of an NEA smaller than 100 m Will address SKGs that are relevant to all objects in that class range (e.g., surface state, local environment) First demonstration of a low-cost, SKG-driven mission Combines asteroid detection/tracking and close proximity science capabilities Paves the way for multi-spacecraft exploration of NEAs Complementary to Earth-based surveys with ground truth connection to astronomical observations Complementary to other missions to NEA: OSIRIS REx, Hayabusa 2 13

14 Summary: Contribution to Space Technology End-to-end demonstration of on-board image processing and science data prioritization and extraction Can feed to future missions with tight resources, e.g., outer Solar system missions If successful, NEAScout will carry autonomous navigation software for demonstration Would help reduce operations cost for future CubeSat/SmallSat missions Autonomy drove the definition of new computer 0.2 U, <5W, 134MIPS x 2 (full duplex), 8GB memory 0.5 U camera is science-grade, also used for navigation Plug and play addition to future missions Solar sail pathfinder first end-to-end solar sail development 14 LEON 3 Sphinx

15 Going to an NEA with a 6U CubeSat is Hard Two few targets accessible with <3U propulsion system True for chemical propulsion, electric propulsion; solar sail has infinite delta-v but is very slow Performance of <1U camera is limited Constrains the size of the target pool Data downlink constraints (1kbps) precludes mosaicking of target s position uncertainty ellipse NEAScout can capture full 6-s ellipse of 1991 VG from 40K km OCC=4 targets requires 100s images Future on-board target extraction is possible, was considered risk for this mission Currently NEAScout has access to only one target at any given time (no target for a few launch windows) Future CubeSat missions should assume at least 12 U 15