Syncom

On 14 February 1963, NASA and the US Department of Defense launched Syncom 1 ¹, the first satellite planned for a geosynchronous orbit and the first to employ range and range-rate tracking. Although Syncom I was lost during injection into geosynchronous orbit, Syncom 2 and Syncom 3 were launched successfully on 26 July 1963 and 19 August 1964 respectively and continued service until after 1965.

The Syncom series were cylindrical, spin-stabilized satellites with a mass of 39 kg. Syncom 2 achieved a 24-hour orbit but with a 33.1° inclination, making it a geosynchronous orbit but not stationary over a single longitude. Syncom 3 was placed in near-geostationary orbit at 180°E with only 1° inclination, effectively appearing fixed in the sky. Each carried two transponders: one supporting two 500-kHz narrowband channels, the other a single 5-MHz wideband channel. The transmitters produced 2.3 W of RF power and operated with uplinks at 1.78–1.85 GHz and downlinks at 2.2–2.3 GHz, supporting full-duplex transmission using both FM and phase shift keying (PSK).

Syncom 2 enabled the first voice call via a geosynchronous satellite, when US President John F. Kennedy spoke with Nigerian Prime Minister Abubakar Tafawa Balewa on 23 August 1963. It also carried telephone, teletype, and facsimile traffic between Africa, Europe, and the United States. Syncom 3 achieved greater fame when it was used to broadcast live coverage of the 1964 Tokyo Olympic Games —the first global TV broadcast relayed from space.