Minimum Fuel-Consumption Stabilization of a Spacecraft at the Lagrangian Points

We consider the motion of a spacecraft described by the differential equations of the three-body problem in the Earth-Moon system. The goal is to stabilize the spacecraft in the neighborhood of the collinear Lagrangian points (which are know to be unstable equilibria) via use of minimum fuel-consumption control. The adopted approach is based on l(1)-optimization of linearized and discretized equations with terminal conditions being the target Lagrangian point. Therefore, the problem reduces to a linear program, and its solution defines pulse controls for the original three-body equations. Upon reaching the desired neighborhood, the spacecraft performs control-free flight until its deviation from the Lagrangian point exceeds certain prespecified threshold. The correction is then applied repeatedly, so that the spacecraft is kept within a small neighborhood of the unstable equilibrium point.