DSCS (Defense Satellite Communications System) was the United States Department of Defense global network of strategic communications satellites, referred to as "Discus". It provided uninterrupted secure voice and high data rate communications between major military terminals and national command authorities.

 

DSCS was developed in three phases. The first was originally known as IDCSP (Interim DSCS) but renamed DSCS 1 upon becoming operational. The second phase involved much larger spacecraft placed in true geosynchronous orbits between 1971 and 1975. Seven of these were still working in 1982 when the first DSCS 3 satellites were launched. A total of 14 DSCS 3I satellites were launched between the early 1980s and 2003.

 

As of September 2021, six DSCS 3 satellites were still operational. From the start of 2007, DSCS began to be replaced by the Wideband Global SATCOM system.