A tracking and data relay satellite (TDRS) is a type of communications satellite that forms part of the Tracking and Data Relay Satellite System (TDRSS) used by NASA and other United States government agencies for communications to and from independent "User Platforms" such as satellites, balloons, aircraft, the International Space Station, and remote bases like the Amundsen-Scott South Pole Station. This system was designed to replace an existing worldwide network of ground stations that had supported all of NASA's crewed flight missions and uncrewed satellites in low-Earth orbits. The primary system design goal was to increase the amount of time that these spacecraft were in communication with the ground and improve the amount of data that could be transferred. These TDRSS satellites are all designed and built to be launched to and function in geosynchronous orbit, 35,786 km (22,236 mi) above the surface of the Earth.
Arabsat-1B was a Saudi Arabian communications satellite which was operated by Arabsat. It was used to provide communication services to the Arab States. It was constructed by Aérospatiale, based on the Spacebus 100 satellite bus, and carried two NATO E/F-band and twenty five NATO G/H-Band transponders. At launch, it had a mass of 1,270 kilograms (2,800 lb), and an expected operational lifespan of seven years.
TDRS-8, known before launch as TDRS-H, is an American communications satellite, of second generation, which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by Boeing is based on the BSS-601 satellite bus.
TDRS-B was an American communications satellite, of first generation, which was to have formed part of the Tracking and Data Relay Satellite System. It was destroyed in 1986 when the Space ShuttleChallenger disintegrated 73 seconds after launch.
TDRS-1, known before launch as TDRS-A, was an American communications satellite, operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW and launched by Space ShuttleChallenger on its maiden flight, STS-6.
INSAT-1B was an Indian communications satellite which formed part of the Indian National Satellite System. Launched in 1983, it was operated in geostationary orbit at a longitude of 74 degrees east. At the end of its seven-year design life it was replaced by the newly launched INSAT-1D, dropping to backup status. In 1992, it was relocated to 93° east, before being decommissioned in August 1993.
TDRS-5, known before launch as TDRS-E, 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 is based on a custom satellite bus which was used for all seven first generation TDRS satellites.
Thaicom 5 was a geostationary communications satellite operated by Thaicom. It was used to provide communications services to Asia, Africa, Middle East, Americas, Europe and Australia.
Orion 3 was an American spacecraft which was intended for use by Orion Network Systems, as a geostationary communications satellite. It was to have been positioned in geostationary orbit at a longitude of 139° East, from where it was to have provided communications services to Asia and Oceania. Due to a malfunction during launch, it was instead delivered to a useless low Earth orbit.
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.
TDRS-4, known before launch as TDRS-D, is an American communications satellite, of first generation, 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.
TDRS-6, known before launch as TDRS-F, 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.
TDRS-9, known before launch as TDRS-I, is an American communications satellite which was operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by the Boeing Satellite Development Center, formerly Hughes Space and Communications, and is based on the BSS-601 satellite bus. It was the second Advanced TDRS, or second-generation Tracking and Data Relay Satellite, to be launched.
TDRS-10, known before launch as TDRS-J, is an American communications satellite which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by the Boeing Satellite Development Center, formerly Hughes Space and Communications, and is based on the BSS-601 satellite bus. It was the third and final Advanced TDRS, or second-generation Tracking and Data Relay Satellite, to be launched.
Galaxy 11 is an American geostationary communications satellite which is operated by Intelsat. It is located in geostationary orbit at a longitude of 32.8 degrees east, where it serves as a backup to the Intelsat 802 spacecraft. It was originally operated at 99° West and later spent most of its operational life at 91° West, from where it was used to provide communications services to Brazil and North America.
GOES-4, known as GOES-D before becoming operational, was a geostationary weather satellite which was operated by the United States National Oceanic and Atmospheric Administration as part of the Geostationary Operational Environmental Satellite system. Launched in 1980, it was used for weather forecasting in the United States, and later in Europe. Following its retirement it became the first satellite to be sent into a graveyard orbit.
TDRS-11, known before launch as TDRS-K, is an American communications satellite which is operated by NASA as part of the Tracking and Data Relay Satellite System. The eleventh Tracking and Data Relay Satellite is the first third-generation spacecraft.
INSAT-1A was an Indian communications satellite which formed part of the Indian National Satellite System. Launched in 1982, it was operated in geostationary orbit at a longitude of 74° east. Following a series of failures, the satellite was abandoned in September 1982, less than 6 months into a seven-year mission.
Intelsat III F-3 was a geostationary communications satellite operated by Intelsat. Launched in 1969 it was intended for operations over the Pacific Ocean; however, it spent most of its service life over the Indian Ocean at a longitude of 63 degrees east.
