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The US activities in military satellite communications systems began in July 1967 with the launch of 3 Initial Defense Communications Satellite Program (IDSCP) satellites. These satellites were designed to be launched in groups of up to 8, and a total of 26 IDSCP satellites were launched in 4 groups by TITAN 3C launch vehicles to near equatorial, 18,300 statute mile orbits. These satellites, each weighing about 100 pounds, drifted from west to east as a rate of up to 30 degrees per day. Each satellite contained a single X-band transponder with a 26 MHz bandwidth. These satellites supported experimental terminals used to evaluate voice, imagery, computerized digital data, and teletype channel using Frequency Division Multiplex/Frequency Modulation (FDM/FM), Differential Phase Shift Keying (DPSK), Multiple Frequency Shift Keying (MFSK), and Spread Spectrum Multiple Access (SSMA) modulation techniques. While designers planned for the satellites to last 3 years, the IDSCP satellites were designed for a 5 year life and were turned off after 6 years.

Alternate Names

  • 02865
  • IDCSP 19
  • IDCSP3-4

Facts in Brief

Launch Date: 1967-07-01
Launch Vehicle: Titan III-C
Launch Site: Cape Canaveral, United States
Mass: 45 kg

Funding Agency

  • Department of Defense-Department of the Air Force (United States)


  • Communications

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office

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