Free-flying Satellite Inspector

Transcription

1 Approved for Public Release (OTR ) Free-flying Satellite Inspector In-Space Non-Destructive Inspection Technology Workshop January 31-February 2, 2017 Johnson Space Center, Houston, Tx David Hinkley Technology and Laboratory Operations The Aerospace Corporation 2017 The Aerospace Corporation

2 Outline What is a free-flying inspector Inspector Satellites AERCam MEPSI COSA AeroCube-4: 3-axis ACS AeroCube-6: 24 hour operations AeroCube-7: Proximity operations Propulsion Camera Cumulos camera suite 2

3 The Aerospace Corporation FFRDC for the USAF since 1960 supporting the nation s national security space Program offices around the country near customers Laboratory division PICOSAT group Engineering division 3,500 employees 3

4 What is a free-flying inspector? Resident on the host until needed Communication with host or to ground direct or both Aware of the local object Can move around Highly automated Cannot harm the host Sensors for inspection purposes Serves a purpose equal to its cost Trust and cost are key enablers 4

5 1999 ESA Study Free-Flying Micro Operator Study, 1999, ESA (Matra Marconi Space) Two Spacecraft considered MICROS: a free flying observer that can do no harm Round, soft skin, low mass SERVISS: a satellite capable of grappling and repairing Missions Operations Surveying >100 meters range Inspection and repair < 1 meter range 5

6 Robots in Practice Lost in space robot Defense, strength, analytical ability Roomba 860 Constant vigilance Does a job we do not want to do 6

7 1990s Miniaturizing of Space Systems 1989 Silicon nanosatellite concept (Aerospace) 1992 Microtechnology for Space Applications (JPL) 1995, 1998 Integrated Microtechnology for Space Applications Start of small satellite revival 7

8 JSC AERCam Autonomous Extra-vehicular Robotic Camera STS-97 (1997): AERCam Sprint : Mini AERCam Image courtesy NASA Image courtesy NASA Reference Mini AERCam: The Miniature Autonomous Extravehicular Robotic Camera, S. Fredrickson, Small Satellites: Past, Present and Future 8

9 2004 Aerospace COSA Co-Orbiting Satellite Assistant Radio; batteries; propulsion; flight computer; heater; gyro; magnetometer 325 gram prototype; 4 dia Mission Mission DV (m/s) Thrust Level (mn) Minimum Impulse bit (mn-s) LEO GEO

10 2002 & 2006 MEPSI Missions MEMS-based Pico Satellite Inspector (MEPSI) STS release 2002 STS release 2006 Opportunity on STPSat-1 (2005) but not ready (Man-rated safety process) 10

11 2006 MEPSI Vehicles Tethered pair Flight computer Single radio Primary battery power VGA cameras Angular rate sensors x3 Reaction wheels x3 Cold gas propulsion (20 m/s) 11

12 2012 AeroCube-4 3-axis attitude control 3 identical vehicles launch from one tube Attitude control algorithm development and demonstration platform Each has three 2 megapixel color cameras with 185, 57 and 22 deg FOVs Demonstrate orbit rephasing using drag control A platform to develop our autonomous ground station network A platform to develop mission planning software 1.3 kg mass 10 x 10 x 10 cm Three AC4 satellites were launched together Currently 52+ months in operation (470 x 770 km x 66 deg) 12

13 2012 AeroCube-4 High-Fidelity, High-Precision Orbit Knowledge Precision of fixes: Position: ~20 m Velocity: ~1 m/s Orbit determination: Feed fixes into TRACE, Aerospace s high-fidelity orbitdetermination software Batch least-squares algorithm for orbit estimation + sequential filter for covariance analysis Output new ephemeris based on high-fidelity model Covariance analysis: After 5 sets of fixes, position uncertainty < 10 m In-Track Uncertainty [m] Uncertainty [m] In-Track Uncertainty Apr Apr Apr Apr Apr Apr Apr Radial and Cross-Track Uncertainty Radial Cross Track 0 17-Apr Apr Apr Apr Apr Apr Apr-13 Reference Operations, Orbit Determination, and Formation Control of the AeroCube-4 CubeSats, J. Gangestad, 2013 Small Satellite Conf 13

14 2012 AeroCube-4 Formation control Sept Oct Nov Dec Jan Feb Mar APR 1,233 km = 10 deg separation Reference Operations, Orbit Determination, and Formation Control of the AeroCube-4 CubeSats, J. Gangestad, 2013 Small Satellite Conf 14

15 2012 AeroCube-4 Plan for multiple photographs of same ground spot during overflight Photo next chart Point LOS at Ground Target 15

16 2012 AeroCube-4 Pointing performance qualification (colors enhanced) 3 deg radius Photo Center Target Point Pointing performance within 3 deg 16

17 2012 AeroCube-4 Northeast US, 24 Jan MP photo 17

18 2014 AeroCube-6 Two spinning spacecraft flying dosimeters Two 0.5U spacecraft Communication between spacecraft Functional up to 400 km range GPS receiver 20-meter fix accuracy Magnetic torque rods Magnetometers Earth and Sun sensors Nominal operation: Sun-pointing Spin about Z-axis at ~30 deg/s Protects payload from Sun exposure Dosimeter science payload S/C ID# Dosimeter Measures A 1 Thin Window Low LET Variant A 2 Thin Window High LET Variant >50 kev electrons & >600 kev protons >600 kev protons A 3 Standard Teledyne >1 MeV electrons & >10 MeV protons B 1 Thin Window Low LET Variant B 2 Thin Window High LET Variant >50 kev electrons & >600 kev protons >600 kev protons B 3 High LET Variant >10 MeV protons 18

19 2017 AeroCube-7b,c Yukon Delta (Alaska) & Bering Sea 10MP imager test photo (AeroCube-7a) Mission Description Optical Communications and Sensor Demonstration (OCSD) Demonstrate star trackers to enable pointing to 0.05 degrees Demonstrate laser downlink communication at 300 Mb/s Demonstrate proximity operations using steam propulsion and variable drag Current status Pathfinder (AeroCube-7a) launched October 8, Partial success: S/W failure in the ACS rendered the payload inoperable, but all other systems are operating nominally. Primary vehicles (AeroCube-7b,c) scheduled for launch in 2017 (waiting on SpaceX) 19

20 2017 AeroCube-7b,c Proximity Operations for AeroCube-7b,c 20

21 2017 AeroCube-7b,c Thermal Vacuum, Propulsion Module Performance Force (mn) 250ms Thrust Time (S) 1 s Thrust Force (mn) grams 10 m/s (for 1.5U satellite) Time (S) Thrust characterized as a function of valve open time and internal tank pressure 21

22 2017 AeroCube-7a,b,c Multifunctional camera board Tracker 1 with undeployed baffle Side color camera Tracker 2 with undeployed baffle Hi-res color camera Image processing board 22

23 2017 Cumulos Payload and AeroCube-7a,b,c Existent cameras systems Satellite Lens F# Lens FL (mm) Pixel Pitch ( m) Nominal altitude (km) GSD (m) Bandpass ( m) AC7a,b,c VIS Cumulos VIS Cumulos SWIR Cumulos LWIR Reference SSC16-WK-44, D. Pack, 2016 Small Satellite Conference 23

24 Inspector Subsystems are Being Developed Resident on the host until needed Communication with host or to ground direct or both Aware of the local object Can move around Highly automated Cannot harm the host Sensors for inspection purposes Serves a purpose equal to its cost An ISS inspector is a unique challenge because the ISS is a man-rated system and large and complicated structure 24

25 Thank You Acknowledgments Dr. Brian Hardy Mr. Darren Rowen Mr. John McVey Dr. Richard Welle Dr. Siegfried Jason The Aerospace Corporation