Encyclopedia Astronautica
1990.01.09 - Leasat 5

Deployed from STS 32 1/10/89; 177 deg W; leased to U.S. government. The Leasat series was developed as a commercial venture to provide dedicated communications services to the U. S. military. Positioned in geosynchronous orbit at 178 deg E in 1990; 72 deg E in 1990-1997; 77 deg E in 1997-1998; 155 deg E in 1998-1999 As of 5 September 2001 located at 155.70 deg E drifting at 0.023 deg W per day. As of 2007 Mar 11 located at 100.05E drifting at 0.003E degrees per day.

The program was initiated as a result of Congressional reviews in 1976 and 1977 which advised increased use of leased commercial facilities. Owned by Hughes Communications, the satellites were designed to provide global UHF communications to military air, sea, and ground forces. The system's primary user is the US Navy, with some support also provided to the Air Force and ground mobile forces (using FLTSATCOM terminals). Hughes was paid $84M per year for each operational satellite. At the end of each satellites' designed 7 year life, the Navy has the option of purchasing the satellite for $15M. The Leasats, along with the Navy's FLTSATCOM spacecraft, are being replaced by the UFO (UHF Follow-on) spacecraft. Spacecraft: Hughes HS-381 bus. Spin stabilised at 30 rpm with despun communications and antenna section. Body mounted solar cells provide 1500 W BOL and NiCd batteries provide power in eclipse. Solid rocket motor for perigee burn, bipropellant system for apogee burn. Hydrazine system for station-keeping. The design is optimised for Shuttle launch and deployment. Payload: Five antennas on the despun platform provide full Earth coverage. Two UHF helices (30 cm diameter, 3.8 m long) one transmit, one receive. Two X-Band horns (one beacon, one receive). One omni TT&C antenna. Channel 1: X-Band uplink, UHF downlink, 25 kHz bandwidth for fleet broadcast using spread-spectrum anti-jamming protection. Channel 2: UHF, 500 kHz bandwidth. Channels 3 to 8: UHF, 25 kHz bandwidth. Channels 9 to 13: UHF, 5 kHz bandwidth.

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