Is extracting oxygen from lunar soil the future of space exploration? |
A new race to the Moon is emerging between the United States and China. Unlike fifty years ago, the goal is no longer just about landing and leaving, but establishing a base that allows for a sustainable presence and extended stays on the surface of our natural satellite. The objective is now to use the Moon as a testing ground for technologies that will enable us to travel further, particularly to Mars.
One of these key technologies is in-situ resource utilization (ISRU), which involves using available resources on-site to produce the consumables necessary for human activities: oxygen, water, rocket fuels, or construction materials. By producing these essentials directly on the Moon, it will be possible to significantly reduce the mass of cargo sent from Earth, thereby reducing the logistical and financial costs of space exploration. Instead of importing these resources from Earth, the goal is to learn how to live on the Moon.
Breaking down lunar dust to extract oxygen
At the dawn of humanity’s sustainable return to the Moon, ISRU is emerging as a strategic pivot. One of the major challenges is producing oxygen from regolith, the layer of soil covering the Moon, primarily composed of small rock fragments and dust. The composition of regolith is complex, mainly consisting of several minerals (plagioclase, pyroxene, olivine) themselves made up of a mixture of metal oxides – chemical compounds that combine oxygen with another element such as silicon, iron, or calcium.
Approximately 40 to 45% of the mass of regolith is composed of oxygen, making it the most abundant element on the lunar surface. Oxygen is ubiquitous, but it does not exist in gaseous form as it does in Earth’s atmosphere. To release the oxygen, the chemical bonds that attach it to other elements in the oxides of the lunar soil must be broken.
One of the methods considered is pyrolysis, a type of chemical reaction that decomposes materials using high temperatures to produce volatile compounds. When applied to regolith, it is possible to heat it until the metal oxides vaporise and........