A
spacecraft attitude control system and method in which an attitude controller is configured for sensing three-dimensional attitude of the
spacecraft, and producing torque signals for stabilizing the
spacecraft in a prescribed attitude in space. At least four mutually
skew reaction wheels are rotated in response to the torque control signals for storing three-dimensional
angular momentum, and speeds of rotation of the wheels are measured. A
reaction wheel speed control processor, responsive to
reaction wheel torque and speed for producing
reaction wheel spin control signals, implements an infinity-norm
algorithm for causing the nullspace components of wheel speed to re-distribute a desired three-dimensional stabilizing
momentum of the spacecraft in such a manner that the maximum speeds of rotation of all the reaction wheels is minimized. As a result, periods between successive
momentum dumping maneuvers are prolonged to the maximum possible.