  In this paper, we consider the rigid spacecraft with an internal rotor as a
regular point reducible regular controlled Hamiltonian (RCH) system. In the
cases of coincident and non-coincident centers of buoyancy and gravity, we give
explicitly the motion equation and Hamilton-Jacobi equation of reduced
spacecraft-rotor system on a symplectic leaf by calculation in detail,
respectively, which show the effect on controls in regular symplectic reduction
and Hamilton-Jacobi theory.
