Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. The programme name is an abbreviation of "synchronous communication satellite".

Common features

Built by Hughes Aircraft Company's facility in Culver City, California, all three satellites were cylindrical in shape, with a diameter of about 71 cm and a height of about 39 cm. Pre-launch fueled masses were 68 kg, whilst orbital masses were 39 kg with a 25 kg payload. They were capable of emitted signals on two transponder at just 2 W. Thus, Syncom satellites were only capable of carrying a single two-way telephone conversations, or 16 teletype connections.

The spacecraft

Syncom 1

Syncom 1 was to be the first geosynchronous communications satellite. It was launched on February 14 1963 with the Delta B #16 launch vehicle from Cape Canaveral, but was lost on the way to geosynchronous orbit due to an electronics failure. Seconds after the apogee kick motor for circularizing the orbit was fired, the spacecraft fell silent. Later telescopic observations verified the satellite was in an orbit with a period of almost 24 hours at a 33° inclination.

Syncom 2

This was the first geosynchronous communication satellite. Its orbit was inclined rather than geostationary. The satellite was launched by NASA on July 26 1963 with the Delta B #20 launch vehicle from Cape Canaveral. The satellite successfully kept station at the altitude calculated by Herman Potočnik Noordung in the 1920s.

For a time, a ship, the USNS Kingsport, acted as a control station and uplink station for this satellite.

Syncom 3

This satellite was the first geostationary communication satellite, launched on August 19 1964 with the Delta D #25 launch vehicle from Cape Canaveral. The satellite, in orbit near the International Date Line, was used to telecast the 1964 Summer Olympics in Tokyo to the United States. It was the first television programme to cross the Pacific ocean.

Syncom IV

The five satellites of the 1980s Leasat program were alternatively named Syncom IV-1 to Syncom IV-5. These satellites were considerably more massive than Syncoms 1 to 3, weighing 1.3 tonnes each.

External links

• Daniel R. Glover's page about NASA Experimental Communications Satellites
• NASA Goddard Space Flight Center descriptions:
  • Syncom 1
  • Syncom 2
  • Syncom 3