Retrieval control of an electro-dynamic tethered satellite in an inclined orbit

This paper presents a nonlinear optimal control scheme for the three-dimensional retrieval process of an electrodynamic tethered satellite system in an inclined orbit. The Legendre pseudospectral algorithm is used to acquire an optimal trajectory to guide the subsatellite into a final position close to the spaceship under mission-related constraints. The optimal control is discretized and solved with the nonlinear programming. The scheme is verified with the numerical simulation. The results shows that the control action is carried out by only adjusting the tensional and electrodynamic forces in the tether.