The Tracking and Data Relay Satellite System (TDRSS) was a concept utilizing communication satellite technology to improve and economize the satellite tracking and telemetry operation. Three geosynchronous satellites (one a standby) will track and receive data from satellites for relay to a ground station. The two active satellites will be separated in orbit by at least 130-deg longitude. Spacecraft serviced by TDRSS will require only one communications system since ground-based telemetry stations will be compatible with TDRSS equipment. TDRSS was intended to support satellite with apogee below 12,000 km. One system will be used for satellites with apogee below 2000 km (the great majority of satellites), and another for those with higher apogee. Use of operating frequencies near 2150 (plus or minus 150) MHz and near 14.3 (plus or minus 0.9) GHz were anticipated.
1 13969U 83026B 12336.76301626 -.00000128 00000-0 10000-3 0 4983 2 13969 013.8682 000.8317 0021630 132.1864 227.9964 00.98745657 81531