| Name of Satellite, Alternate Names | TDRS-3 (Tracking and Data Relay Satellite, TDRS-C) |
| Country of Operator/Owner | USA |
| Operator/Owner | National Aeronautics and Space Administration (NASA) |
| Users | Government |
| Purpose | Communications |
| Class of Orbit | GEO |
| Type of Orbit | |
| Longitude of GEO (degrees) | 84.41 |
| Perigee (km) | 35693 |
| Apogee (km) | 35878 |
| Eccentricity | 0.00219425697714415 |
| Inclination (degrees) | 11.53 |
| Period (minutes) | 1436.06 |
| Launch Mass (kg.) | 3180 |
| Dry Mass (kg.) | 1600 |
| Power (watts) | 1800 |
| Date of Launch | 29-09-1988 |
| Expected Lifetime | 10 yrs. |
| Contractor | TRW Defense and Space Systems Group |
| Country of Contractor | USA |
| Launch Site | Cape Canaveral |
| Launch Vehicle | Space Shuttle (STS 26) |
| COSPAR Number | 1988-091B |
| NORAD Number | 19548 |
| Comments | Backup; still partially operational. |