Thermal absorptivity of a metallic surface contaminated by EAC-1A regolith simulant

Abstract

The aim of this study is to estimate the impact of EAC-1A lunar regolith simulant contamination on the thermal absorption properties of a metallic surface. Masses ranging from 1.0 mg to 1016 mg of the European Astronaut Centre lunar regolith simulant 1 (EAC-1A) were placed on a chemically polished aluminium disc and the total hemispherical absorptivity (αTH) was measured at temperatures TA of the disc itself between 5 K and 100 K. Temperature TR of the thermal radiation source ranged from 20 to 280 K. Even a small amount of EAC-1A (several μg/mm2) increased the original αTH of the bare surface up to thirty times and with increasing volumes the effect was even more prominent. However, αTH significantly decreased at higher T R in case of higher simulant volumes. The results suggest that grains of EAC-1A acted as a thermal shield, preventing the incident thermal radiation to reach the substrate surface. Our findings may have a practical relevance for the thermal management of spacecrafts for exploration missions on Moon and Mars surface.