Along with progress in space exploration, a lot of time and money has been put into developing technologies that could make it easier to use space resources. And finding the best way to make oxygen on the Moon has been the main goal of all of these efforts.
In October, the Australian Space Agency and NASA made a deal to send a rover made in Australia to the Moon as part of the Artemis program. The rover’s goal is to collect rocks from the Moon that could be used to make oxygen on the Moon.
Even though there is an atmosphere on the Moon, it is very thin and mostly made up of hydrogen, neon, and argon. It’s not the kind of gaseous mixture that mammals that need oxygen to live could live in.
In spite of this, there is a lot of oxygen on the Moon. It’s just not in the form of gas. Instead, it is stuck in the layer of rocks and fine dust called regolith that covers the Moon’s surface. If we could get oxygen from the regolith on the Moon, would it be enough for people to live there?
HOW WIDE OXYGEN IS
Many of the minerals in the ground around us contain oxygen. And most of the Moon’s rocks are the same as those on Earth (although with a slightly greater amount of material that came from meteors).
Most of the Moon’s surface is made up of minerals like silica, aluminum, iron oxides, and magnesium oxides. All of these minerals have oxygen in them, but not in a way that our lungs can use.
Minerals can be found on the Moon in different forms, such as hard rock, dust, gravel, and stones that cover the surface. Meteorites have been hitting the moon’s surface for a very long time, so this material is the result.
Some people call the top layer of the Moon’s surface “soil,” but as a scientist who studies soil, I don’t like to use this word. The kind of soil we know is pretty magical and can only be found on Earth. Over millions of years, many different kinds of organisms have worked on the soil’s parent material, regolith, which comes from hard rock.
The result is a matrix of minerals that weren’t in the rocks before. The soil on Earth has many interesting physical, chemical, and biological properties. On the other hand, most of the stuff on the Moon’s surface is regolith in its original, unaltered form.
ONE THING GOES IN, TWO THINGS COME OUT.
The regolith on the Moon is made up of about 45% oxygen. But that oxygen is tightly bound to the minerals we talked about above. We need to put energy into breaking up these strong ties.
If you know about electrolysis, you might have heard of this before. This process is often used to make things on Earth, like making aluminum. Electrodes are used to run an electric current through a liquid form of aluminum oxide, which is often called alumina, to separate the aluminum from the oxygen.
In this case, oxygen is made as a side effect. On the Moon, the main product would be oxygen, and the aluminum (or other metal) that was taken out could be useful.
The process is pretty simple, but there is a catch: it needs a lot of energy. For it to last, it would need to be powered by the Sun or other energy sources that are already on the Moon.
To get oxygen out of regolith, you would also need a lot of industrial equipment. First, we’d have to turn the solid metal oxide into a liquid. We could do this by heating it or by heating it with solvents or electrolytes. We have the technology to do this on Earth, but getting this equipment to the Moon and making enough energy to run it will be a huge challenge.
This year, a Belgian company called Space Applications Services said it would build three test reactors to improve the electrolysis process for making oxygen. As part of the European Space Agency’s in-situ resource utilization (ISRU) mission, they plan to send the technology to the Moon by 2025.
HOW MUCH OXYGEN COULD THE MOON PROVIDE?
Still, if we do figure out how to do it, how much oxygen could the Moon really give us? Well, quite a lot as it turns out.
If we don’t count the oxygen in the Moon’s deeper hard rock and just look at the easily accessible regolith on the surface, we can make some estimates.
On average, there are 1.4 tons of minerals in each cubic meter of lunar regolith. This includes about 630 kilograms of oxygen. NASA says that people need about 800 grams of oxygen every day to stay alive. So 630 kg of oxygen would keep a person alive for about two years (or just over).
Now, let’s say that the regolith on the Moon is about 10 meters deep on average and that we can get all of the oxygen from it. That means that the top 10 meters of the Moon’s surface would have enough oxygen to support all 8 billion people on Earth for about 100,000 years.
This would also depend on how well we were able to get the oxygen and use it. No matter what, this number is pretty amazing.
Even so, things are pretty good for us here on Earth. And we should do everything we can to protect the blue planet, especially its soil, which keeps all life on Earth alive even though we don’t try.