Control strategies for formation flight in the vicinity of the libration points

The concept of formation flight of multiple spacecraft offers many promising possibilities, both for space exploration and the associated technology development. Past studies on formation flight have focused primarily on Earth-orbiting clusters. However, space-based observatory and interferometry missions, such as the proposed Terrestrial Planet Finder and the Micro Arcsecond X-ray Imaging Mission, reflect plans for formation flight in multibody regimes, particularly in the vicinity of the sun-Earth/moon libration points. Two specific tasks are accomplished in this study. First, in a dynamically sensitive regime such as that near the libration points, baseline propulsive requirements are established. A decentralized control strategy based on existing linear and nonlinear control techniques is employed and the results are presented through a series of sample mission configurations. Note that the control problem is formulated to facilitate future tradeoff studies in the libration point environment. The analysis is presented within the context of both the circular restricted three-body problem and the more complete ephemeris model. Once baseline costs are available, the second task is the introduction of potential constraints. These constraints may affect not only the formation control strategies but also the conceptual design of the mission, and their influence on the cost is evaluated.