IDCSP → DSCS-1

IDCSP [USAF]

The IDCSP (Initial Defense Communication Satellite Program) provided the Pentagon with its first geosynchronous communications system and replaced the cancelled ADVENT project.

IDCSP satellites were spin-stabilized 26 sided polygons, 86 cm in diameter, covered with solar panels, and had a mass of 45 kg. The simple satellites featured no batteries and no active attitude control system. Each satellite contained a single X-band transponder with a 26 MHz bandwidth. While designers planned for the satellites to last three years, the IDCSP satellites were kept on for a five-year span and were to turn off after six years.

IDCSP 19 was also called DATS (Despun Antenna Test Satellite), as it tested a more efficient electronically despun antenna platform.

Up to eight were dispersed on a single Titan-3C rocket into slightly sub-synchronous orbit where they would drift about thirty degrees per day. The idea was that a backup was always visible to the earth station if one failed.

IDCSP satellites transmitted reconnaissance photos and other data during the Vietnam war.

They were succeeded by NATO and DSCS-2 true geosynchronous satellites.