Tracking and Data Relay Satellite System (TDRSS)

The Tracking and Data Relay Satellite System (TDRSS) is a space-based communications relay network operated by NASA to provide continuous communications, tracking, and data acquisition services for the International Space Station and for numerous spacecraft in low Earth orbit. By relaying data through geostationary satellites, TDRSS reduces reliance on geographically dispersed ground stations and enables near-continuous contact with orbiting missions.

The TDRAA space segment consists of ten GEO satellites. Steerable, single-access channels can simultaneously transmit and receive at S-band and either Ku- or Ka-band (selectable from ground control). Receive rates are 300 Mbps at Ku- and Ka-band and 6 Mbps at S-band. S-band phased-array antennas can receive signals from five spacecraft at a time—five receive beams can be formed from a 32-element phased array and one transmit beam from a 15-element array.

TDRSS has been deployed in successive generations. First Generation. TDRS-1 was launched 4 April 1983, retired 2009 and disposal orbit in June 2010. TDRS-2 was destroyed 28 January 1986 in the Challenger accident. TDRS-3 was launched 20 September 1988. TDRS-4 launched 13 March 1989, retired December 2011, and disposal orbit April 2012. TDRS-5 was launched 2 August 1991. TDRS-6 was launched 13 January 1993. TDRS-7 was launched 13 July 1995. Second Generation. TDRS-8 was launched 30 June 2000. TDRS-9 was launched 8 March 2002. TDRS-10 was launched 4 December 2002. Third Generation. The third-generation satellites, launched between 2013 and 2017, introduced Ka-band capability and significantly enhanced throughput and flexibility. TDRS-11 was launched 30 January 2013. TDRS-12 was launched 23 January 2014. TDRS-13 was launched 18 August 2017.