We've seen a lot of money and time invested in technologies that can allow for efficient space resource utilization. This is along with advances in space exploration. The focus has been on how to make oxygen on the Moon.
The Australian Space Agency and NASA agreed to send a rover made in Australia to the Moon as part of the Artemis program. This rover will be used to collect lunar rocks which could eventually provide oxygen to the Moon.
The Moon has an atmosphere, but it is very thin and mostly composed of hydrogen, neon and argon. It is not the type of gaseous mixture that would sustain oxygen-dependent mammals like humans.
Despite this, the Moon actually has plenty of oxygen. It's just not in a gaseous state. It's instead trapped in regolith, a layer of rock and fine powder that covers the Moon's surface.
Would it suffice to sustain human life on the Moon if we could extract oxygen from the regolith?
The range of oxygen
Many minerals found in the ground contain oxygen. The Moon is made up largely of the same rocks as Earth, although it contains a little more material from meteorites.
The Moon's surface is dominated by minerals such as silica and aluminum. Although all of these minerals contain oxygen they are not in the form that our lungs can absorb it.
These minerals can be found on the Moon in many forms, including hard rock, gravel, and stones. Over countless millennia, meteorites crashed into the lunar surface.
Although some people refer to the Moon's surface as "soil", I hesitate to use that term as a soil scientist. It is a magical, only on Earth-created substance that we call soil. Over millions of years, it was created by many organisms that worked on soil's parent material, regolith.
This results in a matrix of minerals that were not found in the original rocks. The soil of Earth is rich in remarkable biological, chemical and physical characteristics. The Moon's surface, however, is largely made up of regolith, which is its original, unaltered form.
Two substances go in, one goes out
About 45 percent of the moon's regolith contains oxygen. However, that oxygen is tightly bound to the minerals listed above. We need energy to break down these strong bonds.
This might sound familiar if you are familiar with electrolysis. This process is used to make aluminum. To separate aluminum from oxygen, an electrical current is passed through the liquid form of aluminum oxide (commonly known as alumina) via electrodes.
The oxygen is produced as an afterproduct in this instance. The oxygen on the Moon would be the main product, while the aluminum (or any other metal) would be a byproduct.
Although it is quite straightforward, it is very energy-hungry. It would have to be powered by solar energy, or other sources of energy from the Moon in order to be sustainable.
It would require significant industrial equipment to extract oxygen from regolith. First, we would need to convert solid metal oxide to liquid form by using heat or heat combined with solvents and electrolytes.
Although we have the technology, it will be difficult to move the apparatus to the Moon and generate enough energy to power it.
Space Applications Services, a Belgian startup, announced earlier this year that it was building three experimental reactors for improving the process of electrolysis to make oxygen. The European Space Agency's in situ resource utilization (ISRU mission) will see them send the technology to Moon by 2025.
How much oxygen could Moon supply?
However, how much oxygen can the Moon deliver if we are able to do it? It turns out, quite a bit.
We can make some estimates if we forget about oxygen trapped in Moon's harder rock material and instead consider regolith, which is readily accessible on the surface.
On average, each cubic meter lunar regolith contains about 1.4 tonnes of minerals. This includes approximately 630 kilograms oxygen. NASA states that humans require 800 grams of oxygen per day to live. A person would need to breathe 630 kilograms of oxygen per day to stay alive for approximately two years.
Let's say that the Moon's average regolith depth is 10m. We can extract all the oxygen from this. This means that the Moon's top 10 meters would contain enough oxygen to sustain all 8 billion people for around 100,000 years.
It would also depend on how efficiently we extracted and used oxygen. This figure is amazing, however.
However, it is quite good on Earth. We should protect the blue planet and its soil, which continue to support all terrestrial life.
John Grant, Southern Cross University Lecturer in Soil Science.
This article was republished by The Conversation under Creative Commons. You can read the original article.