Syncom - Syncom IV (Leasat)

Syncom IV (Leasat)

The five satellites of the 1980s Leasat (Leased Satellite) program (Leasat F1 through Leasat F5) were alternatively named Syncom IV-1 to Syncom IV-5. These satellites were considerably larger than Syncoms 1 to 3, weighing 1.3 tonnes each (over 7 tonnes with launch fuel). At 4.26 meters (14.0 ft), the satellites were the first to be designed for launch from the Space Shuttle payload bay.

Hughes was contracted to provide a worldwide communications system based on four satellites, one over the continental United States (CONUS), and one each over the Atlantic, Pacific, and Indian oceans. Five satellites were ordered, with one as a replacement. Also part of the contract were the associated control systems and ground stations.

Leasat F1's launch was cancelled just prior to lift-off and F2 became the first into orbit on August 30, 1984 aboard Discovery on shuttle mission STS-41-D. F1 was launched successfully on November 8, 1984 aboard STS-51-A followed on April 12, 1985 by Leasat F3 on STS-51-D. F3's launch was declared a failure when the satellite failed to start its manoeuvre to geostationary orbit once released from Discovery. On August 27, 1985 Discovery was again used to launch Leasat F4, and during the same mission (STS-51-I) captured and repaired F3. F3 successfully fired its perigee motor and obtained a geostationary orbit, however F4 would later fail and was declared a loss.

The fifth and last Leasat (F5), which was built as a spare, was successfully launched by Columbia mission STS-32 on January 9, 1990.

The last Leasat was retired February 1998.