MARVEL (Microwave heating Ap- paratus for Regolith Variant Experiments for Lunar ISRU) is a collaborative project between the Open Uni- versity (OU), Added Value Solutions UK Ltd. and VI- PER RF. The team has been developing a concept Mi- crowave Heating Demonstrator (MHD) payload since 2019 with the ambition to understand the proper- ties of microwave heated lunar regolith under controlled conditions, explore their potential for lunar construction and resource extraction, and serve as a viable option for selection on future NASA/ESA missions to the Moon. As part of the payload development, the OU team has conducted extensive analysis on the microwave heating behaviour of lunar regolith simulants.

Previous experiments were conducted under atmos- pheric conditions, resulting in significant findings and new insights into the potential use of microwave energy for lunar construction and resource extraction; and providing a rationale for the MHD payload devel- opment. This presentation discusses the preliminary re- sults of further experiments performed under vacuum conditions with lunar simulants representing the lunar mare (JSC-1A) (Figures 1 and 2) and far-side highland material (OPRH3N).