Turning it into breathable air is the tricky part.

With the advancement of space exploration, we have recently seen a lot of time and money invested in technologies that can effectively use space resources. At the forefront of these efforts, we have been focusing on finding the best way to produce oxygen on the moon.

In October, the Australian Space Agency and the National Aeronautics and Space Administration signed an agreement to send an Australian-made rover to the moon according to the Artemis plan. The purpose is to collect lunar rocks and eventually provide breathable oxygen to the moon.

Although the moon does have an atmosphere, it is very thin, mainly composed of hydrogen, neon, and argon. It is not the kind of gas mixture that can maintain oxygen-dependent mammals (such as humans).

In other words, there is actually plenty of oxygen on the moon. It's just not in gas form. Instead, it is trapped in a layer of weathering-a layer of rock and fine dust covering the surface of the moon. If we can extract oxygen from the weathered layer, will it be enough to support human life on the moon?

Oxygen can be found in many minerals underground around us. The moon is mainly made of the same rocks you find on Earth (although there is slightly more material from meteors).

Minerals such as silicon dioxide, aluminum, iron oxide, and magnesium oxide dominate the lunar surface. All these minerals contain oxygen, but it is not a form that our lungs can enter.

On the moon, these minerals exist in several different forms, including hard rocks, dust, gravel and stones covering the surface of the moon. This material is produced by the impact of meteorites hitting the surface of the moon for thousands of years.

Some people call the surface layer of the moon "soil", but as a soil scientist, I am hesitant to use this term. As we know, soil is a very magical thing that only occurs on the earth. It is created by a large number of organisms that have worked on the parent material of the soil-the weathered layer, derived from the hard rock-for millions of years.

The result is a matrix of minerals that did not exist in the original rock. The earth’s soil is full of remarkable physical, chemical and biological properties. At the same time, the material on the surface of the moon is basically the original, unaffected weathering layer.

The weathered layer of the moon is composed of approximately 45% oxygen. But oxygen is closely combined with the above minerals. In order to break those strong bonds, we need to invest energy.

If you know electrolysis, you may be familiar with it. On earth, this process is commonly used in manufacturing, such as the production of aluminum. Electric current is passed through the electrode through the liquid alumina (commonly referred to as alumina) to separate the aluminum from the oxygen.

In this case, oxygen is produced as a by-product. On the moon, oxygen will be the main product, and extracted aluminum (or other metals) will be a potentially useful by-product.

This is a very simple process, but there is one problem: it is very energy intensive. To be sustainable, it needs to be supported by solar energy or other energy sources available on the moon.

Extracting oxygen from the weathered layer also requires a lot of industrial equipment. We need to first convert the solid metal oxide into a liquid form by heating, or in combination with a solvent or electrolyte. We have the technology to do this on Earth, but moving this device to the moon — and generating enough energy to run it — will be a huge challenge.

Earlier this year, Belgium-based startup Space Applications Services announced that it was building three experimental reactors to improve the electrolytic oxygen production process. They hope to send this technology to the moon by 2025 as part of the European Space Agency's In-Situ Resource Utilization (ISRU) mission.

ESA researchers Alexandre Meurisse and Beth Lomax from the University of Glasgow produce oxygen and metals from simulated moon dust in ESA's materials and electronic components laboratory.

In other words, when we manage to pull it down, how much oxygen can the moon actually transport? Well, it turns out a lot.

If we ignore the oxygen present in the hard rock material deeper on the moon—and only consider the easily accessible weathered layer on the surface—we can draw some estimates.

Each cubic meter of lunar weathering layer contains an average of 1.4 metric tons of minerals, including approximately 630 kg of oxygen. NASA stated that humans need to breathe about 800 grams of oxygen every day to survive. So 630 kg of oxygen can keep a person alive for about two years (or just after).

Now let us assume that the average depth of the lunar weathering layer is about 10 meters, and we can extract all the oxygen from it. This means that the first ten meters of the moon's surface will provide enough oxygen to support all 8 billion people on Earth for approximately 100,000 years.

It also depends on how efficiently we extract and use oxygen. Anyway, this number is quite amazing!

Having said that, we are indeed doing very well on Earth. We should do everything we can to protect this blue planet—especially its soil—it can continue to support all terrestrial life even without our attempts.