Moxie: Nasa's lunchboxed

Since February last year, an instrument the size of a lunch box has been successfully generating breathable oxygen on Mars, doing the work of a small tree.

The Mars oxygen in-situ resource utilisation experiment, or Moxie, has been successfully making oxygen from the Red Planet's carbon dioxide-rich atmosphere since it touched down on the Martian surface as part of Nasa's Perseverance rover mission.

A scaled-up version of Moxie could be sent to Mars to continuously produce oxygen at the rate of several hundred trees before humans arrive on the planet, researchers said in a new study.

The study reported that, by the end of 2021, Moxie was able to produce oxygen on seven experimental runs in a variety of atmospheric conditions, including during the day and night, and through different Martian seasons.

During each run, it reached its goal of producing six grams of oxygen per hour — similar to the rate of a small tree on Earth.

It is hoped that at full capacity, the system will generate enough oxygen to sustain humans once they arrive on Mars and fuel a rocket to return the explorers to Earth.

"This is the first demonstration of actually using resources on the surface of another planetary body, and transforming them chemically into something that would be useful for a human mission," said Moxie deputy principal investigator Jeffrey Hoffman, a professor at Massachusetts Institute of Technology's (MIT) department of aeronautics and astronautics.

The current version of the instrument was made small enough to fit aboard the Perseverance rover and is built to run for short periods.

A full-scale oxygen factory would include larger units that would ideally run continuously.

So far, Moxie has shown that it can make oxygen at almost any time of the Martian day and year.

"The only thing we have not demonstrated is running at dawn or dusk, when the temperature is changing substantially," said Michael Hecht, principal investigator of the Moxie mission at MIT's Haystack Observatory.

"We do have an ace up our sleeve that will let us do that, and once we test that in the lab, we can reach that last milestone to show we can really run any time."

If the system can operate successfully despite repeatedly turning on and off, this would suggest a full-scale system designed to run continuously could do so for thousands of hours.

"To support a human mission to Mars, we have to bring a lot of stuff from Earth, like computers, spacesuits and habitats," said Mr Hoffman.

"But dumb, old oxygen? If you can make it there, go for it — you’re way ahead of the game."

The findings are published in the journal Science Advances.