Initial Defense Communications Satellite Program

Initial Defense Communications Satellite Program
Set of IDCSP satellites in truss of Titan IIIC Transtage
ManufacturerTRW
Country of originUnited States
OperatorDefense Communications Agency
ApplicationsSatellite Communications
Specifications
Spacecraft typeSmall satellite
Launch mass45 kilograms (99 lb)
Equipment
RegimeSubsynchronous
Design life6 years
Production
StatusRetired
Launched35 (8 launch failures, 27 in orbit)
Maiden launch16 June 1966
Last launch13 June 1968

The Initial Defense Communications Satellite Program or IDCSP was the first United States Department of Defense communications satellite constellation and the first stage of the Defense Communications Satellite Program (DCSP). Launched in five groups by Titan IIIC launch vehicles to near equatorial, subsynchronous orbits between 1966 and 1968, they were intended to be experimental testbeds. They were so successful that, by the time of the launch of the last set of eight satellites, the IDCSP was deemed operational and renamed Initial Defense Satellite Communications System or IDSCS. This system allowed real-time collection of battlefield intelligence during the Vietnam War. A total of 35 IDCSP satellites were launched, 27 successfully.