Thermal Effects on Very Large Space Structures

Abstract

Radiation thermal effects are studied simultaneously on the orbital motion, attitude motion, and axial deformation of a very large, axially flexible space structure describing a planar pitch motion around the earth. The relative importance of the three known sources of radiation in space environment—direct solar, Earth's albedo, and direct Earth—are studied for low Earth orbit (LEO) and geosynchronous Earth orbit (GEO). Influences of the area‐to‐mass ratio of the structure on thermal effects have been investigated for elliptical orbit. Radiation thermal effects are found to be significant in causing structural deformation and in producing libration in the attitude angle of a large space structure. However, on the orbital parameters of the space structure, the thermal effects are negligible. In LEO, effects of the earth's albedo and its direct radiation on the structure are appreciable, whereas in higher altitude orbits such as GEO, these may be neglected. The area‐to‐mass ratio of the structure is realized to cause a drastic change in the thermal effects on a large space structure.