Thermal Wadis and Compact Rovers: Creating an Affordable Lunar Infrastructure to Enable Resource Evaluations and Technology Demonstrations

Introduction: Many in the space resources community , including scientists, engineers, entrepreneurs, economists and others, have arrived at the conclusion that identifying, locating, harvesting and processing of resources on the moon is possibly the most compelling theme around which to discuss why, when and how humans should return to the moon. While it is clear from ongoing data coming from recent lunar probes that promising resources including water and other volatile species are present, the true abundance and accessibility of these materials cannot be quantitatively established without substantial and widespread in-situ prospecting assays and demonstrations of mining and processing-all in the challenging lunar environment. The potential significance of these resources is clear to lunar and planetary science, but also to the economic sustainability of human space travel to both the moon and beyond. Consequently, robotic " ground truthing " of orbital observations is essential to adequately informed determinations about the value of sending humans back to the moon. Because it is unlikely that one or two robotic resource prospecting and processing missions could adequately evaluate the resource potential of the moon, advocates of completing a resource mapping must consider affordable ways this can be achieved. Improving lunar prospecting productivity must involve surviving the thermal challenges on the moon, especially the cold lunar darkness, and reducing the unit cost and size of individual rover-based assets to enable economies of scale in production and transportation. Thermal Wadis and Compact Rovers: The Thermal Wadi concept[1] is an approach to utilizing modified lunar regolith as solar-thermal energy storage media that can be heated during periods of solar illumination and used as a thermal energy source for mobile assets during periods of darkness. Lunar regolith is modified to improve its thermal properties, then heated using a sun-tracking reflector. During dark periods, the reflector is reconfigured as a radiation umbrella to limit the radiative cooling of the thermal mass and the assets it protects. Ongoing simulations of the thermal performance of the thermal wadi concept have suggested that in equatorial sites a thermal mass no deeper than 50 cm and heated during the lunar day would sustain rover assets for the 300+ hour lunar night within the working tem