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In-situ Radar for Asteroid Characterization and Altimetry Mark Haynes Radar Science and Engineering (334c) Jet Propulsion Laboratory, California Institute.

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Presentation on theme: "In-situ Radar for Asteroid Characterization and Altimetry Mark Haynes Radar Science and Engineering (334c) Jet Propulsion Laboratory, California Institute."— Presentation transcript:

1 In-situ Radar for Asteroid Characterization and Altimetry Mark Haynes Radar Science and Engineering (334c) Jet Propulsion Laboratory, California Institute of Technology CL# This document has been reviewed and determined not to contain export controlled technical data. (c) 2013 California Institute of Technology. Government sponsorship acknowledged. NASA Asteroid Initiative Idea Synthesis Workshop Lunar and Planetary Institute, Houston, TX Sept 30 – Oct 2, 2013

2 Overview In-situ Radar for ARM – Integrated sensing system – Avionics tool – Secondary science Radar features – Self-illumination, shadow/dust independent – Fast, near or far range – Range, Doppler, physical scattering RFI subsections 2. Asteroid Redirect Mission: b) Integrated sensing system … rendezvous, proximity operations … characterize size, shape, mass and inertia properties, spin state, surface properties, and composition….closed- loop control. 3. Asteroid Deflection Demonstration: c)... sub-surface penetrating imaging Asteroid Capture Mission: d) Asteroid composition, internal structure, and physical integrity will likely be unknown until after rendezvous and capture. 5. Crew Systems for Asteroid Exploration:..., prospect for resources,... 29/30/2013

3 Radar Landscape Past and Current Planetary Radar Missions and Science Asteroid Radio Science – Goldstone and Arecibo – NEOs, planetary science (moon, Venus, Mars satellites) Planetary missions with radar – Atmosphere penetration Magellan, Cassini – Sounding MRO / Mars Express Rosetta-CONCERT radar – Landing/Rendezvous MSL, previous rovers Apollo/Shuttle – Earth science remote sensing Asteroid missions (no in-situ radar) – NEAR-Shoemaker, Dawn, Hayabusa, Osiris-Rex Cassini (Titan) Magellan (Venus) Mars Reconnaissance Orbiter (SHARAD) Mars Express (MARSIS) Rosetta (CONCERT) Goldstone Arecibo No in-situ radar on asteroid missions to date 39/30/2013

4 Radar Sounding ws.php?feature=1667 Herique, Alain, and Wlodek Kofman. "Definition of the consert/rosetta radar performances." In EGS General Assembly Conference Abstracts, vol. 27, p Rosetta - CONSERT MARSIS and SHARAD Dielectric inversion (physical properties) Scan-line projection (anatomy) Electromagnetic Scattering Model Iterative Dielectric Estimation Reflection Measurements Shape Map the regolith – Internal structure – Bulk dielectric properties (density) – Anchoring redirect thruster – Sample and boulder return – Improved asteroid trajectory estimate Radar is only active modality capable of sub- surface imaging – Scan-line projection or dielectric inversion 100 MHz to 2 GHz => 20m to 1m depth 3 past/current sounder missions Measurement points Voxelized dielectric model Scan-line projection 49/30/2013

5 Tomography In-situ delay-Doppler asteroid tomography – “Goldstone analog” – Asteroid size, shape, spin, range to target, relative motion – Frequency: 1 to 35 GHz => 1 to 0.1 m resolution – Coarse antenna pointing Close-loop feed back during spacecraft maneuvers – Differential Doppler – monitor spin changes – GPS-proxy Doppler measures motion (rotation) Delay measures range Busch, Michael W., et al. "Physical properties of near-Earth Asteroid (33342) 1998 WT24." Icarus (2008): Delay-Doppler images Shape reconstruction algorithm Shape - Spin Table lookup: determine spin and position 2) Space craft maneuver GPS-proxy 1) Change in spin state (deflect thruster) New-delay Doppler Delay-Doppler Tomography 59/30/2013

6 Rendezvous - Altimetry - Targeting Rendezvous – Apollo: X-band Altimetry/Landing radar – Reduce orbit uncertainty using delay- Doppler echoes Post impact assessment Targeting and guidance – On-route tomography to pinpoint impact time and location Rendezvous > 100k-1M km Landing Single spacecraft impact targeting and guidance 69/30/2013

7 System Configurations System configurations – Single antenna: tomography and sounding – Sounding: separate UHF, VHF, or L-band antenna – Use DSN comm. dish: S, X, Ka-band Power vs. range – Earth observation radars: Satellite (800 km) ~ 1 kW (peak) Airborne (10 km) ~ 1-20 W (peak) Close range (100 m) ~ 1-10 mW (peak) On-board vs. ground based processing – On-board: scan-line sounding, altimetry, targeting, tomo. – Ground-based: dielectric inversion, tomo. End-to-end system simulation 79/30/2013 Tomo. Scan-line sounding Dielectric inversion On-board processingGround processing Sounding antenna Comm. antenna

8 Summary RFI subsections 2. Asteroid Redirect Mission: … integrated sensing system … … rendezvous, proximity operations … … characterize size, shape, mass and inertia properties, spin state, surface properties, and composition … …. closed-loop control … 3. Asteroid Deflection Demonstration:... sub-surface penetrating imaging Asteroid Capture Mission: … composition, internal structure, physical integrity … 5. Crew Systems for Asteroid Exploration:..., prospect for resources,... Sounding Rendezvous Tomography GPS-proxy Altimetry Landing Impact Assessment Impact guidance Sounding Rendezvous Tomography GPS-proxy Altimetry Landing Impact Assessment Impact guidance 89/30/2013 Rendezvous Sounding Tomography

9 Thank you Questions Mark Haynes Radar Science and Engineering (334c) Jet Propulsion Laboratory, California Institute of Technology 99/30/2013

10 Rough Surface Characterization Synthetic aperture radar (SAR) to characterize rough surface properties – Correlation length, rms height, near-surface volume scattering (density estimation) – Rough surface parameters used for thermal inertial modeling – Volume fraction potentially used to estimate  (momentum multiplication factor for impact redirection) – SAR requires Fully polarimetric radar (HH, VV, HV) Shape and attitude knowledge Complementary to LIDAR rough surface estimation SAR backscatter Volume fraction scattering ~ density  inc RMS height H V 109/30/2013


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