The Mission and Spacecraft Library


Part of the Westar program

The Westar series of geostationary spacecraft provide commercial communications services for Western Union. Westar 6 failed to achieve geosynchronous orbit after being deployed from the Space Shuttle. It was later retrieved by another Shuttle mission (November 14, 1984) and returned for refurbishment and relaunch. All Westars have been launched by NASA on a reimbursable basis.

Westar uses the Hughes HS-376 spacecraft design. Spin stabilized with a despun antenna section. Body mounted solar cells. Once on orbit, an outer cylinder deploys downward in "dixie-cup" fashion to increase the solar panel area.

Westar spacecraft typically carried 12 to 24 transponders in the 4-6 GHz range. A single antenna reflector (72 inch diameter) is used with an array of offset feed horns. The reflector uses two polarization-selective surfaces for horizontal and vertical polarized signals.

Country of Origin United States
Customer/User Western Union
Size F1-3: 75 inch diameter x 135 inch high F4-6 (HS-376): 85 inch diameter x 108 inch high (260 inch deployed)
Orbit Geosynchronous
Design Life 10 years

Launch Facts
 Name  Int'l Desig.  Date  Site  Vehicle  Orbit  Mass(kg)
 Westar 1  1974-022A  4/13/74  ESMC  Delta 2914  GEO  500
 Westar 2  1974-075A  10/10/74  ESMC  Delta 2914  GEO  500
 Westar 3  1979-072A  8/10/79  ESMC  Delta 2914  GEO  572
 Westar 4  1982-014A  2/26/82  ESMC  Delta 3910  GEO  1072
    TV, telephone
 Westar 5  1982-058A  6/9/82  ESMC  Delta 3910  GEO  1072
    Voice, TV coverage for Alaska, Hawaii, Puerto Rico, Virgin Islands
 Westar 6  1984-011B  2/3/84  ESMC  STS 41B  LEO  1200
    Deployed from STS 41B 2/4/84; failed to reach proper orbit; recovered by STS-51A

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