CONTROL SYSTEM AND METHOD FOR SPACECRAFT ATTITUDE CONTROL

Position control methods are described for satellites and spacecraft for controlling transition from thruster control to momentum wheel control in a three-axis stabilized spacecraft. Transition from a high-bandwidth, high-torque thruster-controlled stationkeeping (SK) mode to a low bandwidth, low torque momentum wheel On-Orbit Mode is carried out. Usually a unique threshold entry method to automatically initiate the transition mode at the point with the most favorable dynamics. Also, the disclosed method eliminates the use of nutation in conjunction with a deadbeat thruster sequence to correct the spacecraft attitude to improve pointing performance and significantly shorten the time spent in the transition mode.