AAE450 Senior Spacecraft Design Dorrie Byford Week 1: January 18 th, 2007 Communications Group Leader / Autonomous Rendezvous Team Member / Website Designer Satellite Requirements and Autonomous Rendezvous Solutions

AAE450 Senior Spacecraft Design Satellites and Antennas Satellites: Similar in size and capability to TDRSS –Already in place –Good Earth coverage –Has necessary bandwidth requirements –Already proven Antennas: Similar in size and capability to ISS Ku-Band and S- band –Has required bandwidth –Already proven Minimum 5 satellites required –Assumes use of current TDRSS –3 Mars orbiting in 60 deg triangle –2 in large, elliptical halo orbit relatively close to Earth Ku-band and S-band antennas on every vehicle, man and unmanned Mass (kg) Power (kW) Volume (m^3) TDRS1780 (TDRS 8-10), 2500 max (TDRS 1-7) 2 (from solar arrays) 39.3 max (3.4m max diameter when stowed) Ku-Band310<28 max S-Band.16<2<1

AAE450 Senior Spacecraft Design Autonomous Rendezvous Well proven –1998/1999 –Future JAXA vehicles Wide range –500m – 2m Minimum mass increase –Most capabilities already required –Software is basically mass-less

AAE450 Senior Spacecraft Design Back-up Slides

AAE450 Senior Spacecraft Design TDRSS Info SpacecraftLaunch dateLaunch vehicleGSO location TDRS 1Apr. 4, 1983Shuttle STS-649° W TDRS 3Sep. 29, 1988Shuttle STS-26275° W TDRS 4Mar. 13, 1989Shuttle STS-2941° W TDRS 5Aug. 2, 1991Shuttle STS-43174° W TDRS 6Jan. 13, 1993Shuttle STS-5447° W TDRS 7Jul. 13, 1995Shuttle STS-70150° W TDRS 8 (H)Jan. 30, 2000Atlas IIA171.5° W TDRS 9(I)Mar. 8, 2002Atlas IIA170° W TDRS 10(J)Dec. 5, 2002Atlas IIA150.7° W

AAE450 Senior Spacecraft Design Mars Orbiting Satellites

AAE450 Senior Spacecraft Design Halo Orbit (view from Earth)

AAE450 Senior Spacecraft Design HDTV Info 1 HDTV channel = 270 Mpbs Using MPEG-2 Encoding –1 HDTV channel = 5-10 Mpbs Satellites can send ~200 channels at once Using MPEG-2 Encoding, 50 Mpbs (current Ku-band downlink rate) is more than enough

AAE450 Senior Spacecraft Design S-Band Shuttle specs: –Voice: 32 kbps –Commands: 8 kbps –Telemetry: 64 kbps –Forward link High: 72 kpbs Low: 32 kbps –Return link High: 192 kpbs Low: 96 kpbs

AAE450 Senior Spacecraft Design Ku-Band Same specs as S-band Additional 50 Mpbs for video Can be used as back-up system for rendezvous

AAE450 Senior Spacecraft Design NASDA RVR NASDA (now JAXA) created and tested Rendezvous Laser Radar (RVR) in late 90s Tested on two-piece satellite –Named Chaser and Target –Multiple approaches from distances of 2 m to 12 km –Used GPS outside 500 m, RVR from 500 m to 2 m, and proximity operations inside 2 m

AAE450 Senior Spacecraft Design RVR Results All rendezvous performed successfully RVR max error from 500 m – 2 m: m RVR max error from 2 m – dock:.07 m Specs of test satellite: –2900 kg (both pieces combined) –Chaser: 12 m^3 –Target: 1.7 m^3

AAE450 Senior Spacecraft Design Resources newsref/sts-ovcomm.html Mokuno, Masaaki, Isao Kawano, Takashi Suzuki. “In- Orbit Demonstration of Rendezvous Laser Radar for Unmanned Autonomous Rendezvous Docking.” IEEE Transactions on Aerospace and Electronic Systems, April, Vol. 40, Issue 2, pp