Time-optimal three-axis reorientation of a rigid spacecraft

Abstract

New results are presented for the minimum-time rest-to-rest reorientation control problem of a rigid spacecraft with independent three-axis control. It is shown that in general the eigenaxis rotation maneuver is not time optimal. An inertially symmetric (e.g., spherical or cubical) rigid body is examined to demonstrate that an eigenaxis rotation about a control axis of even such a simple body is not time optimal. The computed optimal solution is bang-bang in all three control components and has a significant nutational component of motion. The total number of switches is found to be a function of the specified reorientation angle.