A machine is created that allows it.
Lunar dust, which is a very fine regolith (i.e. the top layer, rocks, weathered and fragmented due to external factors) contains oxygen. However, this oxygen is packed in oxides that form particles of minerals or glass. In the lunar dust samples that were brought to Earth during the Apollo mission, they contained 40 to 45 percent oxygen.
Obviously, such oxygen could be extracted from moon dust, and researchers from the Laboratory of Electrical Materials and Components of the European Space Research and Technology Center (ESTEC) are working on a machine for the European Space Agency to allow this. Even a prototype of this device has already been created.
Until now, the prototype of the device was tested only with the use of so-called simulated moon dust, but this allowed the detection of its most important flaws, and thus – determining what else should be improved in it. First of all, researchers must reduce the temperature that the machine reaches.
How does the equipment developed for ESA work? Well, the device releases oxygen from moon dust using a technique called molten salt electrolysis. Within it, regolith is placed in a metal vessel containing molten salt of hydrochloric acid and calcium, i.e. calcium chloride. This material is heated to 950 degrees Celsius and serves as an electrolyte. At this temperature, regolith remains solid. After passing the electric current through the mixture, oxygen is released from oxides and migrates through the salt up to the anode. During this process, not only molecular oxygen is formed, but also useful metal alloys.
At present, the oxygen obtained with the help of the described method is not stored in any way, but in the future, after the improvement of the machine, this is expected to change. When it comes to metal alloys, ESTEC researchers are thinking about ways to use these metals in lunar conditions.
ESTEC scientists plan to complete the machine in a version that could work on the lunar surface by mid-2020. Such a device may become an important part of future moon bases and colonies. Thanks to it, moon dust will become an extremely important resource for astronauts.