Heat and mass transfers occurring on the surface and within the subsurface of extraterrestrial bodies during natural and future industrial heating processes require knowledge of thermal properties of porous dry and icy materials. A series of experiments have been employed to simulate borehole heating of icy regolith samples under low vacuum (0.1 to 1.5 Torr) and very low temperatures (＞93 K), using JSC-1A analog prepared as "mud-pies" with water contents from 0 to 20% wt. Real-time measurements of temperatures in an array of points and vacuum chamber pressures were recorded. To decipher thermal properties data in this inverse heat equation problem, a 3D finite element method modelling has been used to simulate the behaviour of both the samples and the vacuum chamber. The same model has been used to determine the validity of thermal properties of Lunar icy regolith under extremely high vacuum. The determined thermal conductivities vary with temperature, pressure, ice content, and porosity, while heat capacities vary with temperature, ice content, and porosity. These results should be applicable to research on properties and composition of other rocky and icy extraterrestrial objects or design of water ice prospecting instruments. Most importantly, they should improve our understanding of processes applied in extraterrestrial water mining and visualize the engineering challenges of these processes.
展开▼
