  We consider a PDE-ODE model of a flexible satellite that is composed of two
identical flexible solar panels and a center rigid body. We prove that the
satellite model is exponentially stable in the sense that the energy of the
solutions decays to zero exponentially. In addition, we construct two internal
model based controllers, a passive controller and an observer based controller,
such that the linear and angular velocities of the center rigid body converge
to the given sinusoidal signals asymptotically. A numerical simulation is
presented to compare the performances of the two controllers.
