Spacecraft formation flight at Sun-Earth/Moon libration points.

摘要

Formations of spacecraft, positioned near the libration points of the Sun-Earth/Moon system, have recently received an increase in interest in response to a variety of mission needs. Specifically, missions such as the Micro Arcsecond X-Ray Imaging Mission (MAXIM), Terrestrial Pathfinder (TPF), Stellar Imager (SI) and the European Space Agency's DARWIN all baseline formations of spacecraft to satisfy mission requirements. Replacing the traditional single spacecraft mission with multiple small spacecraft flying in formation is advantageous for these missions, especially when establishing a virtual aperture. These types of formations allow for higher resolution observations than with a single, conventional aperture. The de-emphasis on a single monolithic spacecraft approach to spacecraft mission design also reduces the chance of catastrophic failure of the mission if a single spacecraft can no longer perform its duty.;The present study focuses on the relative dynamics of spacecraft within a formation orbiting near a libration point, such as L2 as examined in this study. A method for finding, understanding, and then exploiting the natural dynamics near a libration point for formation flight is sought. Various formation types (relative halo orbit, fixed-position, and paraboloid) are examined to determine the feasibility of natural formations for various applications.;A method for determining possible DeltaV magnitudes and time between DeltaV maneuvers is also sought to gain an understanding of possible controlled formations that simultaneously exploit the natural dynamics while also controlling the spacecraft in the formation. One approach was identified that uses impulsive maneuvering at specified times to control the spacecraft in the formation desired.