Steering control for skewed scissors pair CMG clusters

An agile steering control arrangement is provided for a spacecraft having a skewed scissor pair control moment gyro (SSP CMG) attitude control arrangement gimbaled with respect to the spacecraft body. The control arrangement includes a steering control process which converts arbitrary spacecraft boresight commands into spin torque and gimbal rate commands for a pair of spinning CMG. The steering control process generates suitable CMG torque commands based on requiring that the boresight nominally follow an arbitrary boresight trajectory described by required angular accelerations for the boresight together with one of various requirements on yaw motion. In this manner, a SSP CMG actuated spacecraft can be steered having tight boresight control while allowing a certain amount of error in yaw about the desired boresight. If spin motor capacities are exceed, new gimbal rates are determined based on saturation wheel spin torque.