Lunchbox-sized instrument MOXIE produces oxygen on Mars

An instrument the size of a lunchbox has proven it can do the work of a small tree by successfully generating oxygen on the dusty surface of Mars.

The instrument — called the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) — has been making oxygen from Mars’s carbon dioxide-rich atmosphere since last year, according to the Massachusetts Institute of Technology (MIT) scientists who pioneered the effort.

MOXIE touched down on the Red Planet’s surface last year as part of NASA’s Perseverance mission in February 2021.

By the end of the year, the instrument was able to produce oxygen on seven experimental runs in a variety of atmospheric conditions, times of day and Martian seasons, the researchers found.

The scientists, who published their findings in Science Advances on Wednesday, said that MOXIE reached its target of producing six grams of oxygen per hour, equivalent to the rate of a modest tree on 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,” MOXIE deputy principal investigator Jeffrey Hoffman said in a statement.

“It’s historic in that sense,” added Hoffman, who is a professor of the aeronautics at MIT and a former NASA astronaut.

Hoffman and his colleagues said they envision a scaled-up version of MOXIE heading to Mars prior to a human mission, with the intent of producing oxygen at the rate of several hundred trees.

At capacity, they explained, such a system should generate sufficient oxygen to both sustain humans when they arrive and fuel a rocket for the astronauts’ return trip to Earth.

The current version of MOXIE was built to fit aboard the Perseverance rover and operates for short periods, starting up and shutting down with each run, according to the study.

Despite its small size and its inability to run continuously, MOXIE has shown that it can reliably and efficiently transform Mars’s atmosphere into pure oxygen, the authors stressed.

The instrument does so by drawing the Martian air in through a filter that first cleans out contaminants, according to the study. The air is then pressurized and sent through an apparatus that electrochemically splits the carbon dioxide-rich air into oxygen ions and carbon monoxide.

Following this process, the oxygen ions are isolated and recombined to create breathable, molecular oxygen, which MOXIE measures for quantity and purity before releasing it into the air.

As MOXIE continues to release oxygen on Mars, the scientists said they plan to push its capacity and try to increase its production during the Martian spring, when atmospheric density and carbon dioxide levels are high.

“The next run coming up will be during the highest density of the year, and we just want to make as much oxygen as we can,” Michael Hecht, principal investigator of the MOXIE mission at MIT’s Haystack Observatory, said in a statement.

“So we’ll set everything as high as we dare, and let it run as long as we can,” Hecht added.

MOXIE may be small, but the scientists said they see the instrument’s success as a promising first step in making a Mars mission breathable for humans.

“We have learned a tremendous amount that will inform future systems at a larger scale,” Hecht said.

And if a full-scale system was able to run continuously, for thousands of hours, it could help potential human visitors lighten their travel load.

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

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