Surface of Mars

Plasma reactor could create oxygen on Mars

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Scientists at the University of Lisbon have used electron beams in a plasma reactor that astronauts could leverage to produce oxygen on the Red Planet.

Vasco Guerra at the University of Lisbon, Portugal, and his colleagues have shown that plasma can be made to vibrate in such a way that it separates carbon dioxide into its components − carbon and oxygen − in a process that could allow humans to breathe in Mars. 

“Mars has very good natural conditions for the production of oxygen using plasma technology,” Guerra said.

Last year, a microwave-size device attached to Nasa's Perseverance rover was able to convert carbon dioxide into 10 minutes of breathable oxygen using the agency’s Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE). In its first activation, the MOXIE instrument produced about 5g of oxygen, equivalent to roughly 10 minutes’ worth of breathing for an astronaut, Nasa said. 

Since then, scientists have been looking for ways to produce more breathing air in the Red Planet, whose atmosphere is made from 95 per cent carbon dioxide.  

MOXIE uses high pressures and temperatures to separate carbon dioxide, and then a membrane made from stabilised zirconium to filter out the oxygen. Guerra's team proposed using a similar membrane but made of plasma, which the scientists said would be more efficient and easier to perform on the Martian surface than MOXIE’s electricity-driven method.

In the lab, Guerra and his colleagues pumped air designed to match the pressure and composition of Mars into metal tubes. By firing an electron beam into the reaction chamber, they were able to convert about 30 per cent of the air into oxygen.

The scientists estimate that the device could create about 14 grams of oxygen per hour: enough to support 28 minutes of breathing, according to an article published in the Journal of Applied Physics.

Michael Hecht, at the Massachusetts Institute of Technology, who oversees the MOXIE project, stated that the new method is unlikely to exceed MOXIE’s efficiency levels because MOXIE is already operating at close to the theoretical limits for oxygen production. 

However, Hecht pointed out other use-cases where plasma can be fine-tuned to vibrate at different molecular frequencies, allowing it to separate other molecules and produce resources that MOXIE can’t, such as nitrogen and nitric oxide.

“There are other processes, such as making nitrogen and NO for fertilisers and things like that, where plasma is much more versatile,” he said. 

According to Nasa, getting four astronauts off the Martian surface would take about 15,000 pounds (6.8 tonnes) of rocket fuel, combined with 55,000 pounds (25 tonnes) of oxygen.

In 2020, the European Space Agency (ESA) said it was making pure oxygen out of lunar dust, another project dedicated to making a human colony on the Moon possible.

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