Dynamics and control of an elastic dumbbell spacecraft in a central gravitational field

The dynamics of a dumbbell shaped spacecraft are modeled as two identical mass particles connected by a linear elastic spring. The equations of motion of the spacecraft in a planar orbit in a central gravitational field are presented. The equations of motion characterize orbit, attitude, and shape (or elastic deformation) degrees of freedom and the coupling between them. Relative equilibria, corresponding to circular planar orbits, are obtained from these equations of motion. Linear equations of motion that describe perturbations from these relative equilibria are presented. New dynamics and control problems are introduced for these linear equations. Controllability results are presented for various actuation assumptions, based on the linear equations.