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Making air out of moondust

on 31 January 2020

A prototype oxygen plant has been set up in the Materials and Electrical Components Laboratory of the European Space Research and Technology Centre, ESTEC, based in Noordwijk in the Netherlands. It is producing oxygen and metal out of simulated moondust.

Samples returned from the lunar surface confirm that lunar regolith — the rocky layer covering the Moon — is made up of 40–45% percent oxygen by weight, its single most abundant element. But this oxygen is bound up chemically as oxides in the form of minerals or glass, so is unavailable for immediate use.

ESTEC’s oxygen extraction is taking place using a method called molten salt electrolysis, involving placing regolith in a metal basket with molten calcium chloride salt to serve as an electrolyte, heated to 950° C. At this temperature the regolith remains solid. But passing a current through it causes the oxygen to be extracted from the regolith and be collected at an anode.

As a bonus this process also converts the regolith into usable metal alloys.

“Being able to acquire oxygen from resources found on the Moon would obviously be hugely useful for future lunar settlers, both for breathing and in the local production of rocket fuel”, comments Beth Lomax of the University of Glasgow, who works on this project as part of her PhD.

Image credit: ESA–A. Conigili