Dynamic thermal interactions between spacesuits and lunar regolith in permanently shaded regions on the moon.

Future human space exploration missions are planned to take humans into permanently shaded regions (PSRs) at the lunar south pole. These areas are among the coldest places in the Solar System and represent a novel operational environment for spacesuits. In addition to this technical challenge, there is scientific interest in volatiles that are cold trapped in PSRs. This paper presents results from several simulations performed to assess the effect of the thermal interactions between the lunar surface and a comparatively warm spacesuit in a permanently shadowed crater on the Moon. After the tools used to perform the simulations and their limitations are discussed, two scenarios are introduced: a crater scenario to investigate the extent and magnitude of the thermal influence of the spacesuit in realistic setting, and a flat plane scenario that is used to analyze the effect of different astronaut translation speeds on the surface temperature changes. While the results show a significant change in lunar surface temperature of up to 60 K within 1.5 m of the astronaut, the effective sink temperature for the spacesuit only changes by a few degrees Kelvin, which is not large enough to have any implications on the design of the spacesuit system. Due to the low thermal conductivity of the lunar regolith and radiation being the dominant mode of heat transfer, the surface temperature increase is only significant for very slow translation rates or periods during which the crewmember remains stationary. The absolute temperature increase can be large enough to release volatiles from their entrapment, which in turn may necessitate a spacesuit design that radiates less heat to protect science objectives. However, further research and experimentation is necessary to determine which species are most susceptible in specific surface compositions and at which temperatures. • Dynamic thermal simulations of a spacesuit in a permanently shadowed lunar crater. • The effects of astronaut translation speed are presented. • The presence of an astronaut causes a significant increase in surface temperature. • The effective sink temperature for the spacesuit changes insignificantly. [ABSTRACT FROM AUTHOR]