Ground controlled conversion of Communications Technology Satellite (CTS) from spinning mode to three-axis stabilized mode

The Communications Technology Satellite was launched on Jan. 17, 1976 and became operational on Feb. 2. The maneuvers and operations performed to convert the spacecraft from its initial spinning mode to its on-station, three-axis mode are referred to as attitude acquisition. During this phase, the maneuver and attitude control actions required were determined by ground based data processing and conducted via ground command. The ground based system is described, with emphasis on the attitude control software; its concept, implementation, development, verification, and flight performance. Experience confirms that this technique provides a flexible alternative to on-board hardware for the geo-synchronous satellite.