Heat and mass transfers occurring on surface and within subsurface of extraterrestrial bodies during natural and future industrial heating processes require knowledge of thermal properties of porous dry and icy materials. This paper investigates thermal properties of icy lunar regolith with various water ice contents and their influence on phase change interface movement. A series of experiments has been employed to simulate borehole heating of icy regolith samples under low vacuum (0.1-1.5 Torr) and very low temperatures (>93 K) using JSC-1A regolith analogs prepared as mud-pies with water contents from 0 to 15 wt%. Cylindrical samples were heated via cartridge heater located in the center of the samples. 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 results provided rough matches with expected thermal properties and the model was used in determination of phase change interface movement in the samples. These results could 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 engineering challenges of these processes.

Thermal mining is a promising architecture, which may provide reliable and 'dirt-simple' means of production of space-sourced water, oxygen and rocket propellant in the future. It is especially tailored to water ice deposits that exist within lunar Permanently Shadowed Regions, where our quest for riches of the Outer Space might begin. Here, the thermal mining extraction system is simulated and analysed with combined heat and mass transfer FEM modelling. The results exhibited that water extraction on the Moon might follow specific production phases, which closely relate to changes in the sublimation interface movement over large timeframes. The production behaviour on the Moon might have many characteristics of relevant production systems on Earth. This may open door for many well-established terrestrial models and production projections to be refitted to extraterrestrial case. It was found that the required water yields of the thermal mining architecture, which make its case economically and commercially viable, are hard to reach without production optimization and new systems development. The production is projected to be significantly hindered by sublimation lag build-up, which would create thermal insulation for the icy deposits. Sublimation lag removal and other strategies might be the answer to that problem.

As icy regolith is believed to exist in the subsurface of permanently shadowed areas near the lunar south pole, there is a growing interest in obtaining samples from these polar regions. To qualify for spaceflight, sampling instruments must demonstrate their ability to operate in the expected environment. However, there is currently no quantitative data detailing the extent and distribution of ice in polar regolith. While work has been done to determine the effects of water ice content in simulants such as JSC-1A, to date there has been no investigation into the properties of icy simulants of the regolith believed to be found at lunar polar regions. A series of experiments has therefore been conducted to determine the properties of icy NU-LHT-2M lunar highland simulant, an approximation of lunar polar regolith, at varying degrees of saturation. A number of procedures for preparing the simulant were tested, with the aim of defining a standardised technique for the creation of icy simulants with controlled water contents. Saturation of the highland simulant was found to occur at a water mass content between 13% and 17%, while cone penetration tests demonstrated that a significant increase in penetration resistance occurs at 5 +/- 1%. Uniaxial compression tests showed an increase in regolith strength with water mass and density, which slows down as the saturation level is reached. The results presented here demonstrate the first characterisation of the properties of icy lunar polar regolith simulants, which can be expanded upon to further the understanding of its properties for use in future instrumentation testing. (C) 2016 COSPAR. Published by Elsevier Ltd. All rights reserved.