Impulsive Control for Formation Flight About Libration Points

The concept of formation flight of multiple spacecraft, near the libration points of the sun-Earth system, offers many possibilities for space exploration. This study focuses on the use of impulsive control to maintain formation flight in the circular restricted three-body problem. Two specific tasks are accomplished in this paper. First, the tangent targeting method, based on a two-level differential correction, is formulated to fully exploit the predetermined error bound. A comparison between the tangent targeting method and traditional targeting method shows that the number of maneuvers can be significantly reduced and the length of time between successive maneuvers can be greatly increased by using the tangent targeting method. The study of the practical convergence of the algorithm is also discussed. The second task is the proposal of a tangent targeting method-based formation-keeping strategy for handling uncertainty introduced by the thrust implementation error. A tradeoff between the formation-keeping accuracy and the number of maneuvers is achieved. Monte Carlo analysis, including 100 trials, demonstrates the effectiveness of this strategy.