Microwaving Lunar Soil Creates a Low-Cost, Stable Building Material for Landing Pads and More

Researchers from the University of Central Florida and Arizona State University have come up with a way to build stable yet low-cost landing pads and even whole buildings on the surface of the moon — by microwaving the lunar regolith, or soil.

"Concrete and steel are used extensively on Earth and have come about from millennia of development and scaling up of industry based upon plentiful water, coal, and air," explains Erik Franks, founder and chief executive of lunar habitation specialist Cislune. "On other planets we don’t have any fossil fuels, and air and water are more valuable than gold. Different processes will be required, and UCF and Cislune are working together to solve these problems with innovative solutions like microwave sintering and soil beneficiation."

Those approaches were tested as part of a study looking at four construction methods for lunar landing pads, which would be required to provide a stable and largely dust-free base for landing crafts' arrivals and departures. Of those, it was microwave sintering — literally melting the lunar dust into a strong construction material — which came out as the most cost-effective, unless a breakthrough dramatically reduces the cost-per-pound of hauling Earth-based building materials up to space.

The approach was given an additional boost by a "beneficiation" technology developed at the UCF, which uses magnetic fields to bring minerals susceptible to microwave sintering closer to the surface ready for processing. "We’ve shown that we can increase microwave absorption by somewhere in the range of 70 per cent to 80 per cent by sorting particles based on magnetic susceptibility," explains co-author Phil Metzger, PhD, of the approach. "The numbers showed us that sintering is actually the best method because it does require some energy, but the cost of the energy is less than the cost of construction and having to bring consumables to the moon."

“Our results were excellent," adds Franks. "Careful beneficiation makes microwave heating of regolith dramatically more energy efficient, so we just need to bring solar panels and can process the lunar dirt into structures like landing pads and buildings.”

The team's work has been published in the journal New Space under closed-access terms; an open-access preprint is available on Cornell's arXiv server.