Even though the Moon lacks atmosphere, it holds massive amounts of oxygen, all combined with the dust on its surface in the form of oxides. In 2019, researchers revealed a study that concentrates on how to extract the oxygen from a Moon’s dust – also known as regolith – simulant.
Now, the first mock-up oxygen plant is set to try completing that extraction on a larger scale. If the technique works, it could offer humans significant resources that will help future lunar expeditions, and perhaps even make possible long-term Moon bases and settlements.
“Having our own facility allows us to focus on oxygen production, measuring it with a mass spectrometer as it is extracted from the regolith simulant,” said chemist Beth Lomax from the University of Glasgow in Scotland.
“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.”
The facility, located at the European Space Agency’s (ESA) European Space Research and Technology Centre in the Netherlands, will utilize the method created by Lomax and her colleagues.
Scientists know, relying upon the returned samples of lunar regolith, that oxygen is, in fact, incredibly abundant in the material, with 40 to 45 percent of the regolith weight being oxygen.
Utilizing an identical copy of lunar regolith designed on Earth, known as lunar regolith simulant, trials have been previously made to understand the proper way to extract oxygen, but the results were poor, complicated, low-yield, or damaging to the regolith.
However, Lomax’s team changed this by utilizing a method called molten salt electrolysis.
The Method Works
First, the regolith was put in a basket lined with meshes, calcium chloride was added, and the mix was heated to about 950 degrees Celsius, a temperature that doesn’t thaw the material.
The team then employed electrical current, which extracted the oxygen and moved the salt to a conductor, from which it can be easily withdrawn. This method can draw out about 96 percent of oxygen from the regolith.
“This is another useful line of research, to see what are the most useful alloys that could be produced from them, and what kind of applications could they be put to,” said materials scientist Alexandre Meurisse of the ESA.
“Could they be 3D printed directly, for example, or would they require refining? The precise combination of metals will depend on where on the Moon the regolith is acquired from – there would be significant regional differences.”
The current environment in the facility is based on commercial deoxidation means, where the oxygen is a rather useless result that gets discharged of. Even so, as the facility develops, a method of storing the oxygen will also be added. The end target is to create a facility that could function on the Moon, using real lunar regolith, and not the stimulant.
“ESA and NASA are heading back to the Moon with crewed missions, this time with a view towards staying,” said Tommaso Ghidini, Head of the Structures, Mechanisms and Materials Division at the ESA.
“Accordingly, we’re shifting our engineering approach to a systematic use of lunar resources in-situ. We are working towards a sustained human presence on the Moon and maybe one day, Mars.”