Along progress in space exploration, we have recently seen a lot of time and money invested in technologies that could make efficient use of space resources. And at the forefront of these efforts is a laser-sharp focus on finding the best way to produce oxygen on the moon.
In October 2021, the Australian Space Agency and NASA signed the deal to send an Australian-made rover to the moon under the Artemis program in order to collect lunar rocks that could ultimately provide breathing oxygen to the moon.
although The moon has an atmosphere, it is very thin and consists mainly of hydrogen, neon and argon. This is not the kind of gaseous mixture that could support oxygen-dependent mammals like humans.
That said, there’s actually a lot of oxygen on the moon. It’s just not in gaseous form. Instead, it is trapped in regolith, a layer of rock and fine dust that covers the surface of the moon. If we could extract oxygen from regolith, would it be enough to sustain human life on the moon?
The width of oxygen
Oxygen can be found in many of the minerals in the earth around us. And the moon is made up mostly of the same rocks you’ll find on Earth (albeit with a slightly larger amount of material coming from meteors).
Minerals such as silica, aluminum and iron and magnesium oxides dominate the moon’s landscape. All of these minerals contain oxygen, but not in a form that our lungs have access to.
On the moon, these minerals exist in several different forms, including hard rocks, dust, gravel, and rocks that cover the surface. This material is the result of meteorite impacts that crash into the lunar surface for countless millennia.
Some people call the surface layer of the moon lunar “soil,” but as a soil scientist I hesitate to use that term. The soil as we know it is quite a magical thing that is found only on Earth. It is created by a huge set of organisms working on the basic material of the soil – regolith derived from hard rock – for millions of years.
The result is a matrix of minerals that were not present in the original rocks. The soil of the Earth is impregnated with remarkable physical, chemical and biological characteristics. Meanwhile, the material on the surface of the moon is mainly regolith in its original, untouched form.
One substance enters, two leaves
You may be familiar with this if you know about electrolysis. On Earth, this process is commonly used in manufacturing, such as for the production of aluminum. An electric current is passed through a liquid form of alumina (commonly called alumina) through electrodes to separate aluminum from oxygen.
In this case, oxygen is produced as a by-product. On the moon, oxygen would be the main product, and extracted aluminum (or other metal) would be a potentially useful by-product.
It’s a fairly easy process, but there’s a catch: it’s very energy-intensive. To be sustainable, it must be supported by solar energy or other energy sources available on the moon.
Extraction of oxygen from regolith would also require significant industrial equipment. We must first convert the solid metal oxide into a liquid form, either by applying heat or heat combined with solvents or electrolytes. we have the technology to do this on Earth, but moving this device to the moon – and generating enough energy to control it – will be a big challenge.
Earlier this year, the Belgian-based startup Space Applications Services announced that it was building three experimental reactors to improve the process of producing oxygen by electrolysis. They expect to send technology to the moon by 2025 as part of the European Space Agency’s on-site resource use (ISRU) mission.
How much oxygen can the moon provide?
However, when we can get it out, how much oxygen can the moon actually deliver? Well, quite, as it turns out.
If we ignore the oxygen bound in the deeper solid rock material of the moon – and simply consider regolith, which is easily accessible to the surface – we can make some estimates.
Each cubic meter (35 square feet) of lunar regolith contains an average of 1.4 tons of minerals, including about 630 kilograms of oxygen. NASA says people need to breathe around 800 grams oxygen per day to survive. So 630 kg of oxygen would keep a person alive for about two years (or a little more).
Now suppose that the average depth of the Moon’s regolith is about ten metersand that we can extract all the oxygen from it. This means that the top ten meters of the moon’s surface will provide enough oxygen to support all eight billion people on Earth for about 100,000 years.
It will also depend on how efficiently we have been able to extract and use oxygen. Nevertheless, this figure is quite amazing!
Having said that, we do it be pretty good here on Earth. And we must do everything in our power to protect the blue planet – and in particular its soil – which continues to sustain all earthly life without even trying.