Apr 13 1974
From The Space Library
13-23 April: NASA launched Westar 1 (Westar-A) , the first U.S. commercial domestic communications satellite, for Western Union Telegraph Co. from Eastern Test Range at 7:33 pm EDT on a Thor-Delta launch vehicle, the first with the TR-201 2nd-stage propulsion unit. One of the nine Castor motors strapped onto the booster failed to jettison until main engine cutoff, decreasing vehicle velocity. Propellant reserves in the 2nd stage provided sufficient additional velocity, however, to put the satellite in the planned transfer orbit with a 36 238-km apogee, 230-km perigee, and 24.7° inclination. Nonmission-related 2nd-stage maneuver-ing experiments, which were to use the propellant reserves, were not performed. NASA's mission objective-to place the satellite in a transfer orbit that would allow onboard propulsion to place it in a stationary synchronous orbit while retaining sufficient station keeping propulsion to meet mission lifetime requirements-was met and the mission was adjudged successful 23 April.
Westar 1 was acquired by a mobile ground station at 9:38 pm EDT and control was turned over to Western Union. The satellite apogee motor was successfully fired at 5:21 pm EDT 16 April and Westar 1 was placed in geosynchronous orbit with a 35 592-km apogee, 35166-km perigee, 23-hr 35-min period, and 0.6° inclination. An onboard hydrazine reaction control system was moving the satellite toward its final position above the equator at 99° W longitude.
Each of 12 transponders aboard Westar 1 could relay 1200 voice circuits, 1 color TV channel with program audio, or data at 50 megabits per sec. The Westar system-including one satellite to be launched in June, one satellite to be held in reserve, and five earth stations-would greatly increase Western Union's capacity for commercial and personal communications. Expected to be operational in August, the system would be the first to interconnect, under one company, satellites and an existing continent-wide, computer-switched, multipurpose terrestrial network. (NASA MOBS, 19 March 74, 24 April 74; GSFC Wkly SSR, 11-17 April 74; NASA Release 74-77; McElheny, NYT, 15 April 74, 1; AP, CSM, 18 April 74; SBD, 26 April 74, 322; GSFC proj off, interview, 7 Nov 75)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
