Three-dimensional temperature profile in a dome-shaped habitat structure on the moon

Abstract

This paper presents the methodology to determine the temperature profile at the surface and through the wall thickness of a monolithic hemispherical dome-shaped habitat structure built on the lunar surface. The three-dimensional thermodynamic equation of heat diffusion is used to determine the temperature profiles using the explicit finite difference scheme. The direct solar radiation and lunar albedo are taken as the heat sources on the habitat structure whereas non-blackbody radiation and habitat albedo were taken as heat sinks. In this study, all the applicable modes of heat transfer – radiation in the external wall surface, convection in the internal wall surface (interior habitat will have air for human missions), and conduction in the structural wall body – have been considered. This temperature analysis study also takes into consideration of the self-shadowing effect of the habitat structure itself. The temperatures at the surface and through the wall thickness of the monolithic dome habitat structure were determined for the habitat structure made of sintered lunar regolith simulant, and for the purpose of comparison, regular terrestrial concrete, for three complete lunar day-and-night cycles. While the maximum temperature of around 390 K was observed at the apex of the sintered lunar regolith simulant dome during the lunar noon, the minimum temperature observed was around 213.5 K during the night time on the external surface of the habitat wall. The corresponding results for the lunar habitat structure made of terrestrial concrete were 364 K and 222.5 K, respectively. At the inner surface of the 40 cm thick habitat structure (in contact with interior habitat environment), the temperature fluctuation (difference between maximum and minimum temperatures) can be up to 30 K for each material type. The results from this study should help to determine the structural stresses and deflections caused by such lunar environment temperature fluctuations and the heat regulation for habitability in the future habitat structure on the Moon. Moreover, the methodology presented in this study should be applicable to conduct parametric studies to evaluate the effect of different parameters on the structural habitat temperature results.