Asymptotic stabilization of motion about an unstable orbit: application to spacecraft flight in Halo orbit

Recently developed control techniques extend the traditional /spl Hscr//sub /spl infin// framework to periodic linear time-varying systems. This paper applies these techniques to the problem of asymptotic stabilization of an unstable orbit. The problem of stabilization of a spacecraft placed in an unstable orbit about the interior Sun-Earth libration point is considered and it is shown that the control effort required by this method is reasonable and can be provided by a low-thrust propulsion system such as an ion engine.