Construction on the Moon: The potential of microwave processing of lunar soil

Levin Prabhu, Vibha (2022). Construction on the Moon: The potential of microwave processing of lunar soil. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.00014ddf

Abstract

The future of human expansion to our nearest neighbour, the Moon and beyond, relies on the utilisation of the available in situ resources on the respective planetary bodies. These resources can be suitable for construction, fuel production, mineral extraction, life support, and consumables required for a sustainable human presence off-Earth. This research describes the use of microwave energy for investigating the potential of lunar construction using lunar regolith. Microwaves of frequency 2.45 GHz and 1.0 kW power are used to heat the lunar soil simulants (LSS) JSC-1A and NU-LHT-3M to predict the microwave heating behaviour of lunar Mare and Highland region samples. The dielectric properties of material define whether it will reflect, absorb, or be transparent to the incident microwave. The temperature-dependent dielectric properties of the LSS are determined using the cavity perturbation technique; both materials were found to be absorbers. Using this data, a theoretical analysis is carried out to predict the microwave heating behaviour of LSS with temperature. A computational analysis using Multiphysics software is then presented to quantify the influence of heat losses on the microwave heating of LSS in a domestic microwave oven used for experiments. These results form the basis of experimental tests in a domestic microwave oven. The combined results of the theoretical, simulation and experimental activities are used to design a bespoke microwave (BM) of industrial standards with better features to handle the heating and melting of LSS; these include the ability to record sample surface temperatures and to alter the atmospheric pressure and composition. Experiments with the BM demonstrate that Mare region samples (similar to JSC-1A) will exhibit better microwave heating susceptibility than the Highland region samples (similar to NU-LHT-3M) on the Moon. Further tests investigated the importance of water content in the lunar soil. It revealed that this water acts likely as a susceptor for highland region samples, which are low absorbers of microwave at 2.45 GHz, 1.0 kW themselves.