Moon dust: ESA contracts firm to extract oxygen

Metalysis plan to convert dust on the moon into its constituent parts, metals and oxygen. How would it work?
17 November 2020

Interview with 

Ian Mellor, Metalysis


The surface of the moon.


This week a British firm announced that they’d won a European Space Agency contract to develop technology to extract oxygen from dust. But not just any dust - Moon dust. Katie Haylor reports...

Ian - We've been contracted to extract oxygen from moon dust.

Katie - That's Ian Mellor, managing director of Metalysis, a British company who specialise in producing metal powders through a process called electrolysis. Electrolysis uses an electric current to separate ionically bonded substances; in this case, moon dust's metal oxides, so metals and oxygen.

Ian - 50% oxygen and 50% metals; typically aluminium, iron, titanium. Our process is an electrochemical process. There are two electrodes; the cathode is the moon dust. You apply a small voltage between the two electrodes. The oxygen is moved from the moon dust, it goes through a conducting electrolyte, it reaches the anode and it is gassed off as oxygen, and leaves the metal powder that can be used for making structures.

Katie - Metalysis have recently been awarded a contract from the European Space Agency to get their chemical process working on the moon. And out there on the moon, it's actually the oxygen from moon dust that they're primarily interested in.

Ian - On Earth the oxygen is a waste byproduct. In a moon context, the oxygen is that the key product. It can be used as a fuel or a propellant; it could be used for breathing to sustain life and activity on the moon.

Katie - It's a rather exciting time in the world space exploration at the moment; although when isn't it, to be honest. But the backdrop to this particular story is NASA's 2024 Artemis program to return to the moon. One key component of this mission is to actually build a base at the lunar South pole to support longer expeditions to the surface. And a plentiful supply of oxygen is critical if we're to support people up there. What's more, Ian reckons this oxygen could be helpful as a fuel. In fact, in an interview with the Guardian, he described the idea as a bit like a lunar petrol station that craft could one day use before making their way out to deeper space. So what's so special about this particular process? Why work towards having this technology on the moon?

Ian - The moon dust is always in the solid state, so there's no dissolving. Whereas in other processes you would actually dissolve the moon dust. It allows us to do the process much more efficiently. There's no need to melt, which is normally associated with high temperatures.

Katie - Less energy required means the process becomes more efficient, which is reassuring, as energy might be at quite a premium when you're not hooked up to the earthly grid.

Ian - The process operates around 900 degrees C. Solar cells provide the electrical energy we would need for the electrolysis.

Katie - And adequately powering this process isn't the only thing to consider when trying to do chemistry on the moon. They're working to get it automated so it wouldn't need a whole lot of human supervision to get on with its task, but there are other practical challenges to consider.

Ian - The questions that we're looking to answer: gravity being one; very dusty environment, the moon, and you don't want to get dust into your equipment; it needs to be a small and as light as possible.

Katie - And what about sustainability? If we're mining on the moon, is it just going to be left with a bunch of holes in it?

Ian - We can actually take the surface moon dust, so we don't need to send out drilling equipment, we don't need to be intrusive. Once you've extracted what you need, what you don't need you can put back and make good.


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