We already know that the Earth’s moon has no atmosphere, which is clearly an obstacle for future astronauts, so it’s crucial to find out how to get the precious oxygen from our satellite. Since we cannot count on carrying oxygen for space missions, it would be unworkable, hence the imperative to produce it right there. A team of scientists from the European Space Agency have created a prototype device that can produce oxygen from lunar dust (of which there is an abundance).
If in 2019 scientists published an article on how to extract oxygen from a moon dust simulator (better known as lunar regolith); in 2020, the first prototype oxygen extractor is ready to be tried on a larger scale at the European Centre for Space Research and Technology in the Netherlands.
The lunar regolith has been studied thoroughly since the Apollo missions brought samples. Later, by reverse engineering the material, scientists imagined that bases could be built with baked regolith bricks and even used to store heat during the long lunar nights. These investigations revealed that oxygen, fortunately, is the most abundant element in the regolith of the Moon: 40-45% of its weight. The problem is that it’s not in breathable form, because oxygen is locked inside rust minerals.
"Being able to get oxygen from the resources found on the Moon would be very useful for future lunar settlers, both for breathing and for local rocket fuel production”, Beth Lomax of the University of Glasgow said in an ESA statement.
Attempts in the past to extract oxygen from lunar regolith have yielded poor results, being a process too complex and with little final performance. However, the current method uses a technique called molten salt electrolysis that can extract up to 96% of the oxygen.
The process works as follows: first, the regolith is placed in a basket lined with mesh then calcium chloride, the electrolyte, is added and the mixture is heated to around 950ºC, a temperature that does not melt the material. After this, an electric current is applied that allows oxygen to be extracted and salt to an anode, where it can be easily removed. And voilà: we already have breathing oxygen. This version can be used as proof of concept and, with greater refinement, one day a moon-like device could be sent to help maintain a sustainable colony.
"To breathe or to produce rocket fuel, obtaining oxygen from the resources found on the moon will be of great benefit to the future lunar settlers," Lomax said.
As if this were not enough, the electrolysis process has another useful by-product: metal alloys of which astronauts could also make good use.
The team is looking to design a "pilot plant" that could be operational on the Moon in the mid-2020’s by extracting real lunar regolith and not the simulated one, which is the one you’ve been working with and has the same composition as the real one but it’s not as valuable as this one. Let us remember that, in a certain way, time is of the essence, because in 2024 man will return to the surface of the Moon and this event will be only the beginning of a new space age.
"ESA and NASA are going to return to the Moon with manned missions, with the intention of staying," said Tommaso Ghidini, Head of the ESA Division of Structures, Mechanisms and Materials. "That is why we are shifting our engineering approach towards a systematic use of lunar resources in situ. We are working to sustain human presence on the Moon and perhaps someday Mars".