IDCSP -> DSCS-1

IDCSP

• American military program: 26 satellites of 45 kg on a 33000 km orbit launched between 1966 and 1968 to built the IDSCS network.
• Lack of launcher power,together with political and economic arguments, delayed the first deployement of a robust communication satellite architecture for the US. military until 1966.
  On 16 June 1966, a Titan 3C rocket deployed 8 satellites, including the first 7 of the IDCSP.
• The IDCSP (Initial Defence Communication Satellite Program), built by Ford Aerospace, provided the Pentagon with its first geosynchronous communications system. IDCSP satellites were 26 sided polygons, 86 cm in diameter, covered with solar panels, and had a mass of 45 kg. When the Titan released its payload, the individual satellites dispensed themselves over 6 hours at slightly different orbital velocities to provide global coverage at points just below GEO altitude at 33915 km. Because they were not perfectly geosynchronous, the satellites drifted about 30 minutes relative to Earth daily, but stayed in view of an Equatorial station for 4,5 days. The satellites maintained attitude control by spin-stabilisation.
• Over the years the network of IDCSP satellites slowly grew to a total of 26 on 13 June 1968.
  The system provided 5 high quality voice, 1550 teletype or 11 tactical voice channels using 20 Mhz bandwidth in the 7266-7286 X-band.
  They linked users 16000 km apart and, from 1967, provided the military with direct communication between South Vietnam and Hawaiï and HawaiÏ to Washington.The military intelligence services in Vietnam transmitted high quality reconnaissance photographs.
• Designed to last 18 months, 5 were still operational after 8 years and 2 after 10 years.
  The IDCSP often referred to as phase 1 of military defence communication emphasised the Cold War needs of nuclear hardening and anti-jamming protection.
  They were succeeded by NATO and DSCS-2 true geosynchronous satellites. IDCSP 19 was also called DATS (Despun Antenna Test Satellite),  as it tested a more efficient electronically despun antenna platform.