Lyapunov Functions and Regions of Attraction for Spherically Constrained Relative Orbital Motion

Abstract This paper considers the problem of a deputy spacecraft constrained to remain a fixed distance from another spacecraft. The relative dynamics of the deputy spacecraft are derived from a velocity-dependent potential function. A constant of motion is presented that aids in the development of multiple Lyapunov functions and stabilizing control laws. Through both numerical and analytical methods, estimates of the region of attraction are presented for each of the control laws. These regions of attraction serve as domains on which it is conclusively known that the equilibrium points are stabilizable. Lastly, a control law with a spatially maximal region of attraction is presented that can be used to track a time-varying trajectory.