LEASAT

LEASAT was a U.S. military UHF satellite communications system built by Hughes Aircraft Company and leased to the U.S. Department of Defense for use by the Navy, Army, and Air Force. It followed the FLTSATCOM and GAPSAT systems and was itself later replaced by the UHF Follow-On (UFO) satellites. Hughes was contracted to provide a global communications capability using four geostationary satellites spaced approximately 90° apart in longitude, providing coverage over the continental United States and the Atlantic, Pacific, and Indian Ocean regions.

LEASAT satellites were spin-stabilized and designed for a nominal operational life of seven years. Each spacecraft carried UHF payloads supporting five 5-kHz channels, six 25-kHz channels, one 500-kHz channel, and a Fleet Broadcast service using an SHF uplink and UHF downlink.

The launch history of the LEASAT program was unusual and complex. The first satellite, LEASAT F1, had its launch cancelled shortly before lift-off. LEASAT F2 was the first satellite launched, on 30 August 1984 aboard Space Shuttle Discovery, but suffered a wideband receiver failure after only four months in orbit. LEASAT F1 was subsequently launched by Discovery on 8 November 1984, followed by LEASAT F3 on 12 April 1985. F3 initially failed to maneuver from low Earth orbit to geostationary orbit after deployment. During the mission that launched LEASAT F4 on 27 August 1985, astronauts manually re-activated F3, successfully fired its perigee motor, and placed it into geostationary orbit; however, the satellite failed soon thereafter and was ultimately moved to a graveyard orbit.

LEASAT F5, originally built as an on-ground spare, was launched aboard Space Shuttle Columbia on 9 January 1990. It remained operational far beyond its design life and was officially decommissioned on 24 September 2015. During the latter part of its service life, LEASAT F5 was leased by the Australian Defence Force, including the Royal Australian Navy, for UHF satellite communications.