Characterizing a Transient Heat Flux Envelope for Lunar-Surface Spacesuit Thermal Control Applications

Abstract

In this paper, a transient thermal simulation approach is used to characterize the heat flux and heat flux rates between the lunar surface and a moving spacesuit model. Five different lunar-surface settings are simulated with craters and boulders at three solar elevation angles (, 10, 90 deg). Heat fluxes and rates are evaluated for different parts of the suit and different characteristic tasks along a given path. The simulated paths are based on Apollo mobility studies. The results indicate that, at lower solar elevation angles, which imply lower lunar-surface temperatures, the thermal impact of surface features becomes more pronounced. In all simulated cases, and for more than 85% of the time, the infrared heat fluxes vary at rates below . The incidence versus magnitude of infrared heat flux rates follows a power law with a negative exponent. Smaller heat flux rates have a higher occurrence at lower surface temperatures, and vice versa. The created lookup tables with task, solar elevation angle, and incident heat fluxes can be used as a baseline in the design and sizing of thermal control hardware for moving objects on the surface of the Moon.