TDRS-C aboard Discovery |
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| Operator | NASA |
|---|---|
| Major contractors | TRW USA (LSP) |
| Mission type | Communication |
| Launch date | 29 September 1988 15:37:00 GMT |
| Carrier rocket | Space Shuttle Discovery STS-26R / IUS |
| Launch site | Kennedy LC-39B |
| Mission duration | 10 years (planned) 20+ years (achieved) |
| Mass | 3,180 kilograms (7,000 lb)[1] |
| Orbital elements | |
| Regime | Geostationary Later geosynchronous |
| Inclination | 0° (BOL) 11.53° (Current) |
| Apoapsis | 35,878 kilometres (22,294 mi) |
| Periapsis | 35,693 kilometres (22,179 mi) |
| Longitude | 151° West (1988) 171° West (1988-1990) 174° West (1990-1991) 62° West (1991-1994) 171° West (1994-1995) 65° East (1995—) |
TDRS-3 , known before launch as TDRS-C, is an American communications satellite which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW, and is based on a custom satellite bus which was used for all seven first generation TDRS satellites.[2]
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The TDRS-C satellite was launched aboard Space Shuttle Discovery during the STS-26R mission in 1988; the first Shuttle flight since the Challenger accident which had resulted in the loss of the previous TDRS satellite, TDRS-B. Discovery launched from Launch Complex 39B at the Kennedy Space Center at 15:37:00 GMT on 29 September 1988.[3] TDRS-C was deployed from Discovery around six hours after launch, and was raised to geostationary orbit by means of an Inertial Upper Stage.[3]
The two-stage solid-propellent Inertial Upper Stage made two burns. The first stage burn occurred shortly after deployment from Discovery, and placed the satellite into a geosynchronous transfer orbit. At 04:30 on 30 September it reached apogee, and the second stage fired, placing TDRS-C into geosynchronous orbit. At this point it received its operational designation. Although the TDRS-2 designation had not been assigned, TDRS-C was given the designation TDRS-3 as NASA did not want to reuse the designation which had been intended for the STS-51-L payload.[4] It was briefly placed at a longitude 151° West of the Greenwich Meridian, before being moved to 171° West before the end of 1988, from where it provided communications services to spacecraft in Earth orbit, including Space Shuttles. In 1990, it was relocated to 174° West, and again in 1991 to 62° West. In 1994 it returned to 171° West.[5][6] In June 1995, it was moved to 85° East, from where it was used primarily for communications with spacecraft such as the Compton Gamma Ray Observatory and the Hubble Space Telescope.[5][7]
As of 2009[update], it was primarily used as a backup satellite.[1] Over time, its orbital inclination had increased due to natural forces, to approximately 12 degrees, as of 2009[update].[8]
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