Abstract
•Lunar regolith’s electric field in microwaves decreases with the sample temperature over 800 K.•The resonance frequency of the cavity is shifted when the sample is heated.•A single hotspot with high electric field intensity is needed to sinter/melt lunar regolith.
Sustainable exploration of the Moon could benefit from a microwave heating-based 3D Printing technology for In-Situ Resource Utilisation (ISRU) purposes such as for the fabrication of habitats and extraction of resources on the Moon. In this context, we have developed a Microwave Heating Demonstrator (MHD) payload concept, which can perform pre-defined ISRU experiments on the lunar surface. The MHD payload would also produce scientifically valuable data in its own right, which would help to establish fundamental criteria for developing a microwave heating-based 3D Printing technique, ultimately enabling lunar construction and other ISRU-derived mission activities.
One of the major design criteria of the MHD payload was to enable sustainable heating performance at low microwave power, e.g., 250 W. This paper discusses some non-negligible phenomena during the microwave heating of lunar regolith, which need to be considered for future mission applications. We also present a design of the MHD payload development, focusing on the heating performance of the microwave cavity.