Abstract

Large scale spacecraft such as a space station are being developed. Their distortion, resulting from solar radiation, terrestrial atmosphere, material degradation, etc. is inevitable. We present a method to measure the distortion. In this method, a linearly polarized ground-based laser beacon and multiple detectors on board the spacecraft are used. Principles and algorithms are formulated assuming that a large scale spacecraft corresponds to a quasi-rigid body, i.e., multiple rigid bodies are flexibly connected. Distortion of the quasi-rigid body is defined by two components: change of distances between rigid bodies, and rotation of each rigid body against the attitude of the spacecraft. The latter is significant to space/earth observations and communications since the rotation changes the direction of telescopes and antenna. Rotational distortion is treated in this work. The orientation of a rigid body is completely specified if three independent rotational angles are known. The three parameters can be determined by a detector which detects both the earth laser beacon’s spot image and the direction of laser polarization. A theoretical study shows that measurements of the distortion, as well as the attitude variation of a large scale spacecraft, are possible with high accuracy by setting multiple detectors aboard the spacecraft.

© 1985 Optical Society of America