Optimal detumbling of defunct spacecraft using space robots

Unmanned spacecraft equipped with manipulators could be used for on-orbit servicing or for capture and removal from orbit of large space debris. After grasping of tumbling target satellite with the manipulator both satellites connected by the manipulator begin to rotate around the common mass center. Changes of manipulator configuration would results in changes of combined moment of inertia and changes in rotational motion of such system. Two satellites connected by the manipulator can be considered as a one rigid body with variable inertia. In this paper we present application of Rapidly-exploring Random Trees (RRT) algorithm for planning changes of inertia tensor of such rotating body in order to minimize rotational kinetic energy and stabilize motion around one axis. Minimization of rotational energy is crucial for the detumbling phase of orbital capture maneuver. Results of numerical simulation is presented and possible directions of future work are indicated.