1. The c:icr 1rnl thermal environment for the observatory ·consists of sofor, earth albedo and earth emission thernl racliaton. These orbital heat flu.,xes vary as a function of orbital altitude and incJination, and time of year. For an anticipated altitude of 300 n mi (345 s mi) and an inclination of 35°, the variation in orbital suntime will be Ba%to 77%. Orbital heat fluxes arc computed for use as boundary conditions in both steadystate and tr.111sientthermal analyses. Overall Configuration