Westar

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Westar was the name for the fleet of geosynchronous communications satellites operating in the C band which were launched by Western Union from 1974 to 1984. There were seven Westar satellites in all, five of them launched and operating under the Westar name.

[edit] Background

Westar 1 (launched on April 13, 1974) has the distinction of being the USA's first commercially launched geosynchronous communications satellite, following North America's first geosynchronous communications satellite, Canada's Anik A1 in 1972. Westar 1 was put into orbit at 99° W in the Clarke belt (99° W now being the home of Galaxy 16).

Westar 2 was launched shortly afterward on October 10, 1974, and Westar 3 was launched on August 10, 1979. Westars 1, 2 and 3 were built by Hughes using the HS-333 platform of spin-scan stabilized satellites. They only had 12 transponders onboard, as opposed to later C-band communications satellites having 24.

The later Westar 4 (launched on February 26, 1982) and Westar 5 (launched on June 9, 1982) satellites, were based on the Hughes HS-376 platform, and had 24 transponders available, as opposed to the 12 on Westars 1, 2, and 3.

Westar 6, also a HS-376 based satellite, was launched on February 3, 1984, and to be put into service afterward, but the perigee kick motor (also known as the Payload Assist Module, or PAM, also known as the PAM-D) on the satellite during its approach to geosynchronous orbit failed, placing it at an improper and inoperable low Earth orbit. It was retrieved on November 16, 1984, by the STS-19 (also known as STS-51A) mission of NASA's Space Shuttle, where it was brought back to earth and refurbished. It was then resold to China, and relaunched on April 7, 1990, as AsiaSat 1. The Space Shuttle mission to retrieve Westar 6, as well as the Palapa B2 satellite which shared the launch payload with Westar 6, was funded by the insurance companies that insured the launch of those two satellites.

An on-ground spare satellite to Westar 6, Westar 6S, was in development by Western Union and Hughes when Western Union decided to divest themselves of their telecommunications-based assets starting in the early 1980s after suffering heavy financial losses. This resulted in Western Union selling the Westar satellite fleet and operations to Hughes in 1988.

Hughes then finished development of Westar 6S, and renamed it Galaxy 6. Modifications were made to it, and Galaxy 6 was launched on October 12, 1990.

Hughes later launched the Galaxy 4 and 5 satellites to replace Westar 4 and 5 respectively, after the latter satellites reached the end of their useful life.

[edit] Uplink sites for Westar

During the life of the Westar fleet, Western Union operated these dedicated uplink sites (now defunct, unless noted) for Westar:

• The Yacolt earth station at Yacolt, Washington (now a satellite uplink site for MCI)
• The Sky Valley earth station, located near Cordelia, California (north of San Francisco)
• The Steele Valley earth station, near Perris, California (southeast of Los Angeles)
• The Kipapa earth station, near Waipio Acres, Hawaii
• The Cedar Hill earth station, at Cedar Hill, Texas (near Dallas)
• The Estill Fork earth station, at Estill Fork, Alabama
• The Lake Geneva earth station, at Lake Geneva, Wisconsin (northwest of Chicago)
• and the Glenwood earth station at Glenwood, New Jersey. Glenwood was the head earth station for the Westar fleet, providing telemetry, control, tracking & uplink services.

[edit] External links

• Description of the Westar satellites at Boeing Satellite System's (formerly Hughes) web site
• Description of Westars 1,2 & 3 at Gunter's Space Page
• Description of Westars 4,5, & 6 at Gunter's Space Page
• The Satellite Encyclopedia's entry for Westar 1
• The Satellite Encyclopedia's entry for Westar 2
• The Satellite Encyclopedia's entry for Westar 3
• The Satellite Encyclopedia's entry for Westar 4
• The Satellite Encyclopedia's entry for Westar 5
• The Satellite Encyclopedia's entry for Westar 6
• Photos of the Westar Sky Valley earth station
• 1977 map of terrestrial microwave relay sites of Western Union, including satellite uplink sites for Westar at the time