For an extended stay on the Moon, humans require habitation with substantial protection from space radiation and micrometeorites. The lunar regolith is a readily available resource in-situ, which can be thermally treated to build lunar habitats/infrastructure and extract oxygen/water. Due to the volumetric heating characteristic intrinsic to microwave heating, it is a more energy-efficient process than solar or laser sintering for large-scale manufacturing and construction. Our proof-of-concept experiments have demonstrated that microwaves can readily heat lunar simulants above their melting temperature. Nevertheless, more information on microwave heating of lunar regolith is required, including the influence of nanophase iron, the contribution from electrostatic effects, and the importance of irregular particle shapes under the real lunar environment. The final goal of the MARVEL project is to develop the flight hardware of a Microwave Heating Demonstrator (MHD) payload for future ESA lunar ISRU missions to demonstrate the potential of microwave heating for construction and the extraction of volatiles such as water and oxygen. The MHD payload will (i) collect up to nine samples (50g each), (ii) heat them with 250 W of input power for 60 minutes and cool down another 60 minutes, and (iii) measure the temperature and the released volatile profile during the experiment. The initial concept of MARVEL at TRL 2, submitted to the ESA RFI of Lunar ISRU Demonstration Platform in December 2018, has continued with support from the UK Space Agency. This has allowed increasing the TRL level of some components, by the selection of critical hardware and the trade-off and risk analysis of the different components required. This project will allow us to establish the crucial criteria for developing a microwave heating-based fabrication method and produce a technology roadmap for the MHD payload and an estimated budget and timeline required to develop the technology to TRL 7.
