Constrained Large Angle Reorientation Manoeuvres of a Space Telescope Using Potential Functions and a Variable Control Gain

In this paper we study large angle rotational maneuvers of a space telescope with pointing constraints. The spacecraft attitude control design is formulated and solved by means of potential functions, thus simplifying the problem of frequent reorientation maneuvers. A novel approach is proposed, where a time varying control gain is chosen such that its instantaneous value depends both on the spacecraft kinetic energy and on the distance of the spacecraft from the forbidden directions. As a result, the spacecraft is able to reach points in the potential field arbitrarily close to a constraint and to maneuver with autonomous capability of guidance and control. A case study illustrates the effectiveness of the proposed methodology.