Environmental Testing of Thermal Control Materials at Elevated Temperature and Intense Ultraviolet Radiation

This paper presents two test campaigns in the frame of the ongoing program for the European Space Agency’s mission toMercury. Improvements on the experimental setup are presented that enable ground-based simulation of such a harsh space environment. The thermal endurance of white ceramic paints is investigated at 350 C. The solar absorptance of all paints increased significantly. Two types of ceramic woven fabrics were irradiated by 17 solar constants of ultraviolet light at an elevated temperature. The available data from the solar absorptance as a function of an ultraviolet dose up to 52,000 equivalent sun hours was extrapolated to the mission’s end-of-life dose of 100,000 equivalent sun hours. The custom-baked Astroquartz 2 was the best performing material with an estimated end-of-life solar absorptance of 0.35.