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TACSAT 1 (also TACOMSAT, Tactical Communications satellite) was the largest and most powerful communications satellite at the time when it was launched into synchronous orbit by a Titan-3C booster 9 February 1969, from Cape Canaveral, Florida. The experimental tactical communications satellite was designed and built by Hughes Aircraft Company, under the direction of the U.S. Air Force Space and Missile Systems Organization, for the Department of Defense.

Two stories high and more than 2.8 meters in diameter, the huge satellite was used by the U.S. Army, Navy, and Air Force to test the feasibility of using synchronous satellites for tactical communications with mobile military field units, aircraft, and ships. TACSAT was taken out of service 16 December 1972, after demonstrating the advantages of this type of satellite communications system.

The first satellite to be spin-stabilized by the Hughes-developed Gyrostat, TACSAT carried three antenna systems: an array of five UHF helices, two microwave horns for X-band communications, and a biconical horn for telemetry and command. Tactical communications experiments in-orbit were conducted in two frequency bands: the standard military UHF band used for air-ground communications and the SHF portion of the X band set aside for military satellite communications.

Since the satellite's strong signals were picked up by all types of terminals, including those with antennas as small as 0.3 meter in diameter, remotely deployed field units communicated with their headquarters and each other through the satellite. The high RF power transmitted by the spacecraft permitted simultaneous access by many users.

Nation: USA
Type / Application: Communication
Operator: USAF
Contractors: Hughes
Equipment: 2 hard-limiting repeaters (UHF and SHF)
Configuration: HS-308
Propulsion: ?
Power: Solar cells (body mounted), batteries
Mass: 730 kg
Orbit: GEO
Satellite COSPAR Date LS Launch Vehicle Remarks
TACSAT 1 (TACOMSAT 1, OPS 0757) 1969-013A 09.02.1969 CC LC-41 Titan-3C


  • Boeing: TACSAT 1
  • Donald H. Martin: Communication Satellites, Aerospace Press, 1991, p 97-98