TDRS satellites

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.

TDRS-12, known before launch as TDRS-L, is an American communications satellite operated by NASA as part of the Tracking and Data Relay Satellite System. The twelfth Tracking and Data Relay Satellite, it is the second third-generation spacecraft to be launched, following TDRS-11 in 2013.

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-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 on its maiden flight, STS-6.

TDRS-7, known before launch as TDRS-G, 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 as a replacement for TDRS-B, which had been lost in the Challenger accident, and was the last first generation TDRS satellite to be launched.

TDRS-3, known before launch as TDRS-C, is a first-generation American communications satellite, 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.