DART Mission Overview 15 August 2017 Cheryl Reed, APL Project Manager & DART Team

Transcription

1 Approved for Public Release, August 2017 Asteroid Impact & Deflection Assessment (AIDA) Solar System Exploration Program DART Mission Overview 15 August 2017 Cheryl Reed, APL Project Manager & DART Team Goddard Space Flight Center Johnson Space Center Langley Research Center Glenn Research Center Marshall Space Flight Center Planetary Defense Coordination Office 12/2016 1

2 DART: A Planetary Defense Mission 2010 National Research Council Committee Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies NRC Recommendation: If Congress chooses to fund mitigation research at an appropriately high level, the first priority for a space mission in the mitigation area is an experimental test of a kinetic impactor along with a characterization, monitoring, and verification system, such as the Don Quixote* mission that was previously considered, but not funded, by the European Space Agency. This mission would produce the most significant advances in understanding and provide an ideal chance for international collaboration in a realistic mitigation scenario. DART is the first test in a Planetary Defense Technology Demonstration Plan 2 *Earlier ESA mission proposal not selected, but has now evolved to AIDA

3 Regimes of Primary Applicability of the Four types of Planetary Defense Mitigation 3 Image courtesy of Tim Warchocki

4 DART Objectives & Goals DART is the first test in a Planetary Defense Tech Demo Plan Primary Test Objectives Demonstrate kinetic deflection of realistic scale asteroid and reduce key risks in autonomous navigation and targeting Improve impact models by constraining the momentum enhancement due to ejecta through comparison to pre-impact predictions Refine CONOPS for deflection missions and inform planning for planetary defense decision process and policy definition Concept Programmatic Goals/Constraints Provide an affordable, design-to-cost implementation (w/o Launch & HQs. UFE, ~$205M, Phase A-E) (relative to 2022 impact opportunity) Implement under Class D mission risk classification Leverage NEO Program initiatives and APL DOD capabilities Design for a commercial rideshare opportunity Demonstrate NASA s NEXT Solar Electric Propulsion Technology Fly other enabling technologies as appropriate ROSAs, CoreSat avionics, SMARTNav, RLSA Provide for international collaboration opportunities; measurement independent 4

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6 DART is targeting the Didymos system in October, 2022 Preliminary shape model of the Didymos primary from combined radar and light curve data, diameter ~780 m. The secondary (not imaged) may be more elongated. Cheng AF et al. (2015) Acta Astron., 115: 262 Cheng AF et al. (2016) Planet. Space Sci., 121:27 Michel P et al. (2016) Adv. Space Res., 57:2529 Primary Diameter 780 m ± 10% Secondary Diameter Total System Mass 163 m ± 18 m (5.278 ± 0.54) kg Component Bulk Density 2,100 kg m 3 ± 30% Primary Rotation Period Component Separation Secondary Orbital Period Spectral Class ± h /-20 m / h Didymos is a well-characterized asteroid that approaches close to Earth, enabling groundbased observations of impact demonstration The secondary ( Didymoon ) is realistic scale Small enough to deflect kinetically and measure result Smaller NEOs represent a more frequent threat to Earth S 6

7 First Kinetic Impact Test at Realistic Scale for Planetary Defense DART target much smaller than the Deep Impact target Comet 9P/Tempel 1 Deep Impact target DART target Didymos moon 7

8 DART Baseline Trajectory (Deep Space) Launch Jan , 640 kg (1 case within launch period) Clear GEO Altitude, May , 600 kg (120 day) Clear Upper Van Allen Belts, June , 592 kg (143 day) Escape Aug , 568 kg (214 day) Continuous tangential thrusting, except for eclipses, tracking and phasing arcs. Flyby: Mar , 640 kg, km/s (67 day coast arc) Impact Impact: Oct , 529 kg, 5.92 km/s (82 day coast arc) Earth-Centered Frame E-10d E-30d TCM 2c TCM 2b E-2d TCM 2d E-12hr Handoff to SMARTNav E-60d TCM 2a IPS Cruise Period CB21 Flyby Didymos Impact IPS Cruise Period 1 Rideshare to Initial GTO, Jan Sun-Centered Inertial Frame *All planned, deterministic maneuvers are accomplished with IPS *Zero planned, deterministic, impulsive DV by mission design in baseline reference trajectory Flyby-30d TCM 1a Flyby-10d TCM 1b 2001 CB21 Flyby

9 DART Mission Design - Path To Terminal Guidance Autonomous Navigation and Targeting Intercept (~10.9M km; 6.8M miles from Earth) 1. Ascent / Boost 2. Cruise / Calibration 3. Target Detection / Coarse Acquisition 4. Scene Classification Direct Launch or Low-Thrust Spiral* <6-9 months for EP> <10 8 km from target> Flyby of PHA allows sensor calibration and control-gain tuning <7 months until impact> <10 8 km from target> Weeks prior to impact, seeker detects primary <2 months until impact> <10 7 km from target> Seeker counts and classifies closely spaced objects <3 hours until impact> <65,000 km from target> 5. Target Selection 6. Homing Until Intercept 7. Impact Assessment With sufficient confidence, seeker selects target and locks on. Pro-Nav executes precision engagement and is robust to target uncertainties <1.5 hours until impact> <32,000 km from target> <Executed until final 2 minutes> <6.0 km/s Impact> Earth tracking and AIM quantify intercept success. <3 months> 9 * months total flight time

10 Didymos Reconnaissance and Asteroid Camera for OpNav (DRACO) Imager Design Summary Heritage design based on LORRI from New Horizons mission Uses of a CMOS ~2k x 2k (BAE scmos) detector instead of LORRI CCD Data Processing functions implemented in Avionics IEM instead of LORRI DPU Visible narrow angle camera with a large aperture and good optical performance LORRI optics, with in-progress trade of switching from Al optics to less thermally sensitive material Instrument Uses Provides images used for distant, 30-day out, ground-based optical navigation to Didymos Provides images and centroids for close, autonomous guidance to Didymos (SMARTNav) Provides final images of the surface used for determining impact location and impact site morphology. These are used for impact modelling and understand effectiveness of impact. DRACO Overview Aperture 200 mm F Number f/12.63 Wavelength 350 nm 850 nm FOV 0.29 degree full angle IFOV 2.5 urad PSD* (300 km) 1.0 meter PSD* (150 km) 0.5 meter PSD* (30 km) 0.1 meter SNR (30 days) >7 SNR (final) >100 *Pixel Sample Distance 10

11 Spacecraft Layout Stowed Configuration Y Z X ROSA ARRAYS Z NEXT Engine (with Top Hat ) X Y RLSA 8X Thruster Sun Sensor 2X LGA Star Tracker 2X ROSA 2X Battery DRACO 11

12 NEXT-C Project: DART Collaboration Performance Characteristics Thruster Power, kw Specific Impulse, sec Thrust, mn Thrust to-power, mn/kw Thruster Efficiency Lifetime - Xenon Throughput, kg > 600 NASA s Evolutionary Xenon Thruster (NEXT) began as a technology development project NEXT-C project s objective is to transition the NEXT technology to flight and create a commercially available product (Managed by NASA GRC) The NEXT-C project is producing two flight qualified thrusters and two Power Processing Units (PPUs). A single thruster and PPU (with simulators, testbeds, test data & documentation) are GFE to the DART project. Flight project preparing to support a mission(s) with GFE flight hardware delivery in early DART is the first flight of NEXT and will complete the system qualification for future deep space missions. 12

13 DART Baseline Launch Readiness Date (LRD) (Commercial Rideshare) 20 Dec Mar Oct month launch period 7-month Spiral Flyby Cruise Nominal Trajectory 07 Oct month launch period 7-month Spiral Cruise Backup Trajectory Nominal LRD includes 5-month launch period 7-month spiral to Earth escape Asteroid 2001 CB21 flyby Impact in Oct 2022 Backup trajectory eliminates the flyby Launch period extended to 7 months Spiral duration and impact date unchanged Opportunities above can be somewhat replicated two years later for a 2024 impact opportunity, however, you loose the global 1-2 meter ground-based optical telescope and radar capabilities. There may be other NASA-mission co-manifest opportunities but these need to be studied. 13

14 JHU/APL Proprietary DART Investigation Team & Working Groups 14 DART Core Team Andrew Cheng (APL) AIDA Coordination lead Andrew Rivkin (APL) DART Investigation Team Lead Angela Stickle (APL) DART Investigation 1 lead Cristina Thomas (PSI) DART Investigation 2 lead Derek Richardson (UMD) DART Investigation 3 lead Olivier Barnouin (APL) DART Investigation 4 lead; shape model development Eugene Fahnestock (JPL) DART Investigation 5 lead Steven Chesley (JPL) Dynamics lead Brent Barbee (GSFC) V&V lead Investigation 1: Modeling and Simulations of Impact Outcomes Megan Bruck Syal (LLNL) impact modeling using spheral and SPH Paul Miller (LLNL) planetary defense interpretation and applications Emma Rainey (APL) impact modeling using CTH Collaborators: Dan Durda (SWRI), Galen Gisler (LANL); Keith Holsapple (UW); Kevin Housen (Boeing); Daniel Jontof-Hutter (Penn St); Naor Movshovitz (UCSC); J. Michael Owen (LLNL); Cathy Plesko (LANL); KT Ramesh (JHU); James Richardson (Arecibo); Pete Schultz (Brown) Investigation 2: Remote Sensing Observations Paul Abell (JSC) Strategic Knowledge Gap (SKG) and human exploration applications Lance Benner (JPL) radar observations Shantanu Naidu (JPL) Analysis of radar data Collaborators: Michael Busch (SETI); Ellen Howell (UofA); Matthew Knight (Lowell/UMD); Emily Kramer (JPL); Jian-Yang Li (PSI); Tim Lister (LCOGT); Amy Mainzer (JPL); Nicholas Moskovitz (Lowell); Michael Nolan (UofA); Dagmara Oszkiewicz (Lowell); David Osip (LCO); William Ryan (NMT); Eileen Ryan (NMT); Amanda Sickafoose (MIT/SAAO); Jessica Sunshine (UMD); Audrey Thirouin (Lowell); Cristina Thomas (PSI); Padma Yanamandra-Fisher (JPL) Investigation 3: Dynamical and Physical Properties Julie Bellerose (JPL) gravity and dynamics Daniel Scheeres (U Colorado) geotechnical properties Douglas Hamilton (UMD) orbital dynamics Collaborators: Eric Asphaug (ASU); Bill Bottke (SWRI); Toshi Hirabayashi (Purdue); Jay McMahon (U Colorado); Paul Sánchez (U Colorado); Gal Sarid (UCF); Simon Tardivel (JPL); Kevin Walsh (SWRI) Investigation 4: Science Proximity Observations Nancy Chabot (APL) DRACO Instrument Scientist Carolyn Ernst (APL) impact site morphology characterization Investigation 5: Ejecta Dynamics and Evolution Stephen Schwartz (ASU) WG co-lead, ejecta simulation, low speed ejecta Collaborators: Douglas Hamilton (UMD); Christine Hartzell (UMD); Toshi Hirabayashi (Purdue); Daniel Jontof-Hutter (Penn St); Ludmilla Kolokolova (UMD); Jim Richardson (PSI); Gal Sarid (UCF); Gonzalo Tancredi (Ciencias) We expand community participation through annual open international workshops (Held 3 to date) JHU/APL Proprietary

15 DART Has a Parallel Ground-Based Observation Program Didymos Observations Have data in hand for four observing sessions: 25 February UT from GTC (Spain) 25 February UT from MMT (Arizona) 27 February UT from SALT (South Africa) 2 March UT from MMT Mutual events seen in data reduced so far Allows timing of mutual events for rest of apparition 14 more observing sessions scheduled through end of April Next up: 10 March at Magellan (Chile) Team in process of incorporating new data with data UT (Hours) February UT: Gran Telescopio Canarias February UT: MMT Instrumental Magnitude (r) Didymos 25-Feb-2017 MMT photometry 0.7 Mutual events: Didymos B occulting or being eclipsed by Didymos A 15

16 Observing Strategy for Impact Epoch Network of telescopes around globe to be used in observing campaign Observatories on 5 continents allow potential for near continuous optical coverage with 4-m or larger telescopes Telescopes as small as 1 m can obtain useful data, mitigating risk of bad weather or equipment failure at specific sites Goldstone and Arecibo radar allow measurements to be made throughout impact period Option to use space-based telescopes HST observations during impact period possible JWST rate limits allow observation ~6 weeks after impact Future space-based NEO survey 16

17 Outline of 2022 Impact Observing Campaign DART impact during excellent apparition: Didymos at V ~ 14-15, very well placed for Chile, observable from other observatories Planetary Radar participation hugely useful Didymos primary and secondary are separated by up to 0.02 arcsec when 0.08 AU from Earth Marginally resolvable with ALMA (sub-mm), Magellan adaptive optics Post-impact brightening and ejecta stream as extended object ( coma ) may be observable from Earth Debris cloud analogous to YORP-driven MBCs? P/2013 P5 ~250 m, observed at 1.1 AU distance from Earth 17

18 Observing Campaign Selected telescopes expected to be available Facility Telescope(s) Location(s) Capability IRTF 1 3.0m NH: Mauna Kea Low & high res IR spectroscopy Keck m NH: Mauna Kea Low & high res Optical & IR spectroscopy, AO NH: Mauna Kea, Gemini 2 8.0m Optical and IR imaging & spectroscopy, AO SH: Chile Magellan 2 6.5m SH: Chile Optical and NIR imaging & spectroscopy Las Campanas 1 2.5m SH: Chile Optical imaging & spectroscopy DCT 1 4.3m NH: Arizona Optical & NIR imaging & low res spectroscopy NH: Canary WHT 1 4.2m Optical & IR imaging & spectroscopy, AO Islands 4 8.2m, ESO 1 3.6m, 1 3.5m SH: Chile Optical & IR imaging & spectroscopy, AO, IR high res spectroscopy NH: Canary GTC m Optical imaging, Optical low res spectroscopy Islands MRO 1 2.4m NH: New Mexico Optical imaging, Optical low res spectroscopy NH: 1 2m, 3 1m LCOGT 11 1m, 2 2m Optical imaging, Optical low res spectroscopy SH: 1 2m, 8 1m IUCAA 1 2.0m NH: India Optical imaging AAO 1 3.9m SH: Australia NIR imaging & spectroscopy m, SAAO SH: South Africa Optical imaging & low res spectroscopy 1 1.9m

19 DART Firsts First mission to measure asteroid deflection by constraining the ejecta momentum amplification factor of a kinetic impactor, as well as the initial conditions (impact conditions, target s properties) First mission to fly NASA s NEXT solar electric propulsion technology. First mission (with AIM) to study a binary asteroid system, its origins and interior structure Contributes valuable data to many disciplines, i.e., planetary defense, science, human exploration and resource utilization. 19

20 Project Status DART is in Phase B Launch Readiness Date (LRD) for 2022 impact opportunity is December 2020 PDR is scheduled for February, 2018 spdrs are now underway KDP-C is scheduled for 13 March 2018 International contributions are being explored, studied A LV RFI for commercial rideshare will soon be released through FedBizOps. RFI notes APL as the procuring entity. Visit us at: 20