Comparative Study on Space Qualified Paints Used for Thermal Control of a Small Satellite.

A satellite with a passive thermal control system mainly uses thermal coatings and paints to maintain temperatures within safe operating limits. Satellite coatings, exposed to harsh space environments such as ultraviolet (UV) radiation and atomic oxygen (AO), undergo physical damage and thermal degradation, which must be considered by the satellite thermal designer for design optimization and cost reduction. In this paper, we have briefly reviewed the effects of space environment effects on degradation of satellite coatings. To study the consequences of paints degradation on the thermal performance of satellites with passive thermal control, a small cubical satellite in Low Earth Orbit (LEO) has been considered. The satellite’s bottom surface faces the Earth, and the top surface faces deep space. The satellite’s lateral sides are covered with solar panels, and the top surface, which acts as the satellite radiator, is covered with white paint. The satellite orbit is sun-synchronous with an inclination angle of 99°. Three radiator coatings (Chemglaze A276 and SG121FD white paints, and AZW-11LA ceramic white coating) have been used in turn, and the satellite has been thermally analyzed for each case. In these analyses, beginning-of-life and end-of-life optical properties have been used to predict the satellite temperatures, before and after degradation of the coatings. The analyses results show the importance of stability of optical properties of the thermal coatings for the long-term thermal control of satellites. On considering the rate of thermal performance degradation, lower production cost, and ease of application on satellite surfaces, SG121FD white paint is recommended as suitable satellite radiator paint for use in satellite thermal control applications, with the same design requirements, mission life and orbital parameters as the satellite considered in this study.