TDRS-D being deployed from Discovery |
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| Operator | NASA |
|---|---|
| Major contractors | TRW USA (LSP) |
| Mission type | Communication |
| Launch date | 13 March 1989 14:57:00 GMT |
| Carrier rocket | Space Shuttle Discovery STS-29R / IUS |
| Launch site | Kennedy LC-39B |
| Mission duration | 10 years (design life) 22 years (actual) |
| Mass | 3,180 kilograms (7,000 lb)[1] |
| Orbital elements | |
| Regime | Geostationary Later geosynchronous |
| Inclination | 10.15° |
| Apoapsis | 35,805 kilometres (22,248 mi) |
| Periapsis | 35,771 kilometres (22,227 mi) |
| Longitude | 41° West (1988-2005) 46° West (2005—) |
TDRS-4, known before launch as TDRS-D, is an American communications satellite which was operated by NASA as part of the Tracking and Data Relay Satellite System from 1989 until 2011. It was constructed by TRW, based on a custom satellite bus which was used for all seven of the first generation TDRS satellites.[2]
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TDRS-D was launched aboard Space Shuttle Discovery during the STS-29R mission in 1989. Discovery launched from Launch Complex 39B at the Kennedy Space Center at 14:57:00 GMT on 13 March 1989.[3] TDRS-D was deployed from Discovery a few hours after launch, and was raised to geostationary orbit by means of an Inertial Upper Stage.[3]
The twin-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 03:30 GMT on 14 March, it reached apogee, and the second stage fired, placing TDRS-D into geosynchronous orbit.[4] At this point it received its operational designation, TDRS-4. It was placed at a longitude 41 degrees west of the Greenwich Meridian,[5][6] from where it provided communications services to spacecraft in Earth orbit, including the Space Shuttle and International Space Station. In 2005, it was relocated to 46° West.[5]
TDRS-4 completed its planned mission in November 2011, and was removed to a disposal orbit 350 kilometres (220 mi) above GEO belt, per International Telecommunications Union (ITU) and United Nations (UN) recommendations, in early December 2011.[7] As of 5 December 2011[update] NASA was still completing the effort to fully passivate the vehicle.[7]
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