TDRS-3
| TDRS-C aboard Discovery | |
| Mission type | Communication | 
|---|---|
| Operator | NASA | 
| COSPAR ID | 1988-091B | 
| SATCAT no. | 19548 | 
| Mission duration | Planned: 10 years Elapsed: 36 years, 8 months, 22 days | 
| Spacecraft properties | |
| Bus | TDRS | 
| Manufacturer | TRW | 
| Launch mass | 2,224.9 kg (4,905 lb) | 
| Dimensions | 17.3 × 14.2 m (57 × 47 ft) | 
| Power | 1700 watts | 
| Start of mission | |
| Launch date | 29 September 1988, 15:37:00 UTC | 
| Rocket | Space Shuttle Discovery STS-26 / IUS | 
| Launch site | Kennedy Space Center LC-39B | 
| Contractor | Rockwell International | 
| Orbital parameters | |
| Reference system | Geocentric orbit | 
| Regime | Geostationary orbit | 
| Longitude | 151° West (1988) 171° West (1988–1990) 174° West (1990–1991) 62° West (1991–1994) 171° West (1994–1995) 85° East (1995–2009) 49° West (2009–) | 
| Epoch | 29 September 1988 | 
TDRS-3, known before launch as TDRS-C, is an American communications satellite, of first generation, 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.