Oxygen is one of the most important resources for exploring space. Not only is it a critical component of rocket fuel, it is also necessary for astronauts to breathe somewhere outside the Earth's atmosphere. The availability of this abundant resource is not a problem – it is widespread throughout the solar system. One place where it is particularly common is the lunar regolith, the thin layer of material that makes up the lunar surface. The difficulty lies in one of the quirks of oxygen – it binds to almost everything.
About 45% of the regolith's weight is oxygen, but it's bound to materials like iron and titanium. In order to use both the oxygen and the materials it is bound to, they must be separated. And a British company, with the support of the European Space Agency, has started testing a technique to assess its potential effectiveness on the moon.
The company, called Metalysis, already makes earthbound machines that can isolate metals in bound configurations with oxygen. In a novel step, the company used its process to extract oxygen and metals from the simulated lunar regolite, which here on earth is the best substitute for the actual ground on the moon.
A UT video shows how in situ resource use, including the generation of oxygen from regolith, can revolutionize space exploration.
The experiment worked well, but requires fine tuning to increase the amount of oxygen released. The process submerges the oxygenated material in a bath of molten salt and then passes an electric current through the combined salt and regolith. The electrical charge allows oxygen to break its bonds with the metals that hold it in oxide form, and they can then migrate freely and collect on a charged electrode. A mixed metal powder then remains.
This metal, if used properly, can be used in material separation systems such as 3D printing, but so far it has put the cart in front of the horse. The Metalysis experiment carried out, carried out in a washing chamber the size of a washing machine, is extremely power hungry and focuses primarily on metal extraction. All three properties must be changed if the process is to be used effectively in space.
Video describing Metalysis' basic technology with a focus on metal extraction for the terrestrial market.
Photo credit: Research & Impact on Sheffield Youtube
The chamber itself must shrink to fit properly with other space-based devices. The demand for electricity must be reduced because there is a severe lack of energy on the moon. And since oxygen is more valuable than metals on the moon, the process needs to be optimized with different reactants to extract the maximum amount of oxygen from the material.
ESA researchers are working on the simulated lunar dust experiment.
Image credit: ESA
However, the engineers at Metalysis and ESA still have some time before their process is needed on the moon. NASA's current ambitious Artemis program plan is to get one person back to the moon in four years. If there is a system in place that can generate rocket fuel and breathable gas for them when they arrive, it will be a huge step towards securing future exploration missions from the lunar surface.
ESA – converting moon dust into oxygen
SpaceRef – Converts moondust into oxygen
Discover – extract air from lunar dust: Scientists create a prototype of a lunar oxygen system
Lead Image Credit: ESA