ATTITUDE CONTROL OF STABLE AND UNSTABLE SATELLITES IN ELLIPTIC ORBITS

A previously developed method for determining a time-independent feedback control law for '%'stable'%' satellites, nonlinear equations of motion, Pontryagin's Maximum Principle, and phase plane methods are used in the development of a time-independent, feedbac, attitude-control system. Digital computer simulation studies of the developed acquisition control system, with the dynamics provided by the nonlinear equations of motion, are presented. In these studies practical time delays are introduced into the developed acquisition control. The developed acquisition control is combined withpreviously developed station-keeping controls, which efficiently results in high-accuracy earth- pointing motion of stable and unstable satellites in elliptic orbits about an oblate earth with atmosphere.