Abstract: his paper describes the theory of the steady state caloric method for measuring solar absorptance as The variation of solar absorptance of some thermal control coatings with the temperature and the angle of incidence was measured by this method. The measured results indicated that the variation of solar absorptance with the angle of incidence is distinct for second s urface mirrors and bright anodized aluminum coatings. The absorbed solar flux of some satellites was calculated on the basis of these measured results. The calculation showed that the variation of solar absorptance with the angle of incidence must be considered to calculate precisely the absorbed solar flux for the satellites with second surface mirror or anodized aluminum coating.