Study set to extract oxygen from Moon rock regolith

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Efforts to colonise the Moon could be given a significant boost with molten salt and electrolysis technology that extracts oxygen from Moon rock.

moon rock
Indicative Lunar lander with In Situ Resource Utilisation (ISRU) payload (Image: Redwire Space Europe)

To this end, Thales Alenia Space has signed a 1m study contract with the European Space Agency for a payload concept to do just that.

For a sustainable habitation on the Moon, humans will need to utilise resources that they find on the Moon rather than transport these resources from Earth; one of these resources is oxygen.

Thales Alenia Space teams in the UK have worked with AVS, Metalysis, Open University and Redwire Space Europe to specify a demonstration payload for a European Space Agency Lunar Mission that uses molten salt and electrolysis to extract oxygen from Moon rock regolith.

According to the ESA, samples returned from the lunar surface confirm that lunar regolith is made up of 40–45 per cent percent oxygen by weight and is its single most abundant element. This oxygen, however, is bound up chemically as oxides in the form of minerals or glass.

The new payload concept will demonstrate that In Situ Resource Utilisation (ISRU) can be performed on the Moon efficiently and to produce oxygen in the quantities required by future Moon colonies.

In a statement, Andrew Stanniland, CEO of Thales Alenia Space in the UK said: “The adaption of processes and tools to the space environment, many of which we take for granted on Earth, will be critical in many areas of our future. I am proud that our dedicated teams will be leading this study together with our valued partners AVS, Metalysis, Open University and Redwire Space Europe to solve the complex challenge of creating oxygen to sustain life on the lunar surface”.

In 2020 technology developed by project partner Metalysis was used at the European Space Research and Technology Centre (ESTEC) in the Netherlands to extract oxygen from regolith simulant.

ESTEC’s oxygen extraction method involved placing regolith in a metal basket with molten calcium chloride salt serving as an electrolyte, which was heated to 950°C. The regolith remains solid at this temperature but passing a current through it causes the oxygen to be extracted from the regolith and migrate across the salt for collection at an anode. The process also converts the regolith into usable metal alloys.

The process being investigated in the latest study aims to reduce the salt mass needed, reduce the operating temperature and increase the amount of oxygen produced.