  In this paper, a dynamic-programming approach to the coupled translational
and rotational control of thruster-driven spacecraft is studied. To reduce the
complexity of the problem, dynamic-programming-based optimal policies are
calculated using decoupled position and attitude dynamics with generalized
forces and torques as controls. A quadratic-programming-based control
allocation is then used to map the controls to actuator commands. To control
the spacecraft in the event of thruster failure, both the dynamic programming
policies and control allocation are reconfigured to cope with the losses in
controls. The control allocation parameters are adjusted dynamically to ensure
the satellite always approaches the target from the side with two operative
thrusters to achieve a stable control. The effectiveness of the proposed
dynamic programming control is compared with a Lyapunov-stable control method,
which shows that the proposed method is more fuel-efficient in tracking the
same path.
