Collision avoidance algorithms for satellite formation flying by using aerodynamic drag

Collision avoidance approach for formation flying satellites in a Low Earth Orbit by aerodynamic drag is proposed. Energy optimal control to obtain tangent trajectory to forbidden zone is developed. A piecewise-linear approximation of optimal control is considered. Comparison of the two algorithms in terms of accuracy is performed. The accuracy of the control in the presence of discrete control and command execution error is studied.