Comparison of Station-Keeping Algorithms for an Interior Libration Point Orbit inthe Sun-Earth+Moon Elliptic Restricted Three-Body Problem

摘要

A spacecraft near a Lagrange (libration) point orbit between the Earth and theSun can study the important interaction of the Sun's corona with the terrestrial environment. However, the spacecraft will drift from the nominal (unstable) path. The accumulated error in the spacecraft's position and velocity relative to the nominal path after a predetermined period of range and range-rate tracking can be computed. This error, or uncertainty, in the spacecraft state is measured through simulations, commonly referred to as orbit determination error analysis, and is presented as either variances or standard deviations of the state vector elements. The state uncertainty computed in the error analysis can then be input to a station-keeping algorithm. The algorithm computes control maneuvers that return the spacecraft to the vicinity of the nominal path. Variations in orbital shapes and sizes may, however, have some effect on the station-keeping costs. Several algorithms are derived and are used to test differences in station-keeping costs for orbits of different size and shape. Statistical hypothesis tests for equality of means are used in the comparisons.