Water ice present at the lunar poles represents a potentially crucial resource for allowing a sustainable cislunar economy [1]. Microwave heating offers an efficient technique to extract the water ice directly from the regolith [2]. Volumetric heating throughout a sample means that the low thermal conductivity of lunar regolith can be overcome allowing efficient heat transfer and large-scale water extraction.

In this work, icy regolith samples have been created with two different forms of ice: permafrost and granular.  Both types of samples were made to a water content of 5 wt. % and used LHS-1 as the simulant choice. Two grain size distributions for granular ice were used with average grain sizes of 1.3 and 2.7 mm. A bespoke microwave heating unit was used to heat the samples using 250 W microwaves for 60 minutes. A dynamic mass instrument was used that was able to measure the real time mass of samples in situ. This allowed the mass loss over time to be measured.

The average extraction profiles for all sample types can be seen in Figure 1. It has been found that high extraction was possible for all samples in 60 minutes (>80 %). All the profiles are similar in that a minimum amount of heating time was required before water was extracted. Both the permafrost and small granular ice samples had similar extraction profiles, while the large granular ice samples show a distinctly different profile as the ice is released in discrete sections. I will present these results and demonstrate the feasibility of using microwave heating as a water extraction technique.