This report describes a program for the development of an attitude control and stationkeeping subsystem which uses an electrically heated ammonia propulsion system. The objective of the program was to demonstrate the operation of a high performance ammonia thruster and a zero-gravity ammonia feed system in response to the stimulus of control electronics typical of future military spacecraft. A mission analysis was performed and a three-axis stabilized, 2000-pound, synchronous altitude spacecraft was selected. A survey of several competitive control electronics concepts resulted in the selection of a pulse ratio modulation approach. A three-axis design was prepared, and a single-axis control electronics unit was fabricated. A four-nozzle thruster was developed. A feed system capable of delivering only vapor phase ammonia to the thruster in a zero gravity environment was developed. The single-axis control electronics, a thruster and a feed system were integrated for a one month closed-loop test. The system was subjected to acquisition, limit cycle, stationkeeping, and reacquisition modes of operation. (Author)
Attitude Control and Stationkeeping Subsystem Program
1968
255 pages
Report
Keine Angabe
Englisch
Manned Spacecraft , Rocket Engines & Motors , Scientific satellites , Attitude control systems , Space propulsion , Ammonia , Flight control systems , Synchronous satellites , Weightlessness , Specific impulse , Configuration , Pulses , Temperature , Heating elements , Thrust , Meteorological satellites , Electronic equipment , Mission profiles , Reconnaissance satellites , Communication satellites(Active) , Stationkeeping