Researchers are already working on ways to grow food in space, and icy deposits that could provide water are known to exist on the Moon..Besides being available for drinking, such water could be split into its constituent elements of hydrogen and oxygen using electricity from solar panels. Such electrolysis is already the main way of making oxygen on the International Space Station (ISS).
The European Space Agency (esa) announced on January 17th that a prototype oxygen-generating plant using regolith has been set up at its research centre in the Netherlands. Not only could such a machine use a readily available material to make breathable air for people living on the Moon, it could also be used to produce rocket fuel, says Beth Lomax of the University of Glasgow, who is working on the project.
Oxygen, in the form of oxides, is the most abundant element in lunar regolith, accounting for 40-45% of its mass. Metalysis has developed a form of electrolysis that can extract high-value metals such as tantalum (used in electronic capacitors) and niobium (used to make super-strong alloys) from powdered metal oxides mixed into a bath of molten salt. Although the process operates at around 900°C, it does not involve melting the materials, which would require much higher temperatures. Using a carbon electrode, the molten-salt process strips oxygen from the oxides as carbon dioxide and carbon monoxide.
By tinkering with this process, Dr Lomax and her team (a British company based near Rotherham) were able to devise a form of molten-salt electrolysis that produces oxygen directly. They tested it on commercially available simulated regolith, a substance based on a recipe obtained from samples brought back from the Moon.
The researchers have designed a new, oxygen-proof prototype that should be able to collect all of the gas liberated from regolith. This prototype could be automated and it should also be possible to reduce its operating temperature.
The agency plans to produce a version of the machine that could be flown to the Moon and operated there. A single unit would produce around six tonnes of oxygen a year—though bigger generators could be developed.
If feasible, that means a regolithic oxygen-generator would not only help keep people alive on the Moon but could also provide the materials to build and fuel a rocket to transport them deeper into space.