Perserverance puts oxygen on Mars.

On today’s episode of “science fiction becomes science reality”, NASA planted a tree on Mars.

Well, fundamentally speaking, they did!

One of the first steps in terraforming a planet is to be able to breathe normally as we do on planet Earth. Oxygen is only 0.13% on Mars, compared to 21% in Earth’s atmosphere. As transporting oxygen to Mars is simply not practical, this means we’ll have to find a way to create oxygen on Mars itself if we were to inhabit the place. And NASA just demonstrated that it is possible.

In a series of many “firsts”, the Perseverance rover, NASA’s latest six-wheeled robot on the Martian surface, successfully converted carbon dioxide (96% of Mars’ atmosphere) into breathable oxygen on April 20, the 60th Martian day, or sol, since the robot landed on February 18.

A tree of technology.

Among the myriad of scientific instruments carried by the rover is a gold-plated, toaster-sized box holding the golden key to human survival on Mars. Designed by a team of MIT scientists led by Michael Hecht, the Mars Oxygen In-Situ Resource Utilisation Experiment (MOXIE) inhaled carbon dioxide and exhaled oxygen through a process called solid oxide electrolysis.

Illustration of the MOXIE instrument, depicting the elements within the instrument. GIF credits: NASA/JPL.


First, MOXIE sucks in carbon dioxide. Carbon dioxide gets compressed and filtered. Carbon dioxide then gets really, really hot. Atoms in carbon dioxide get super heated, and are forced to separate into carbon monoxide and oxygen ions. Oxygen ions form a union, becoming the oxygen we need. Carbon monoxide and pure oxygen then leave MOXIE, divorcing for good.

The carbon monoxide expelled into the atmosphere might become problematic if this goes on a super large scale, though. Since this current experiment is merely a proof of concept, maybe this is an aspect that scientists will have to consider and solve in the future.

The first breath MOXIE took produced about 5 grams of oxygen in an hour, enough for an astronaut to stay alive for 10 minutes. Hmm… not quite long enough just yet! Drawing its energy from the rover’s radioisotope power system, MOXIE was designed to generate up to 12 grams an hour – equal to what a large tree would produce.

A return ticket for future Martians.

MOXIE will be remembered for paving the way for possible future Mars missions as oxygen is crucial not only for future human habitation of Mars, but also for the rocket propellant needed for humans to make the trip home to Earth.

To burn its fuel, a rocket must have more oxygen by weight. “To get four astronauts off the Martian surface would require seven metric tons (15,000 pounds) of rocket fuel and 25 metric tons (55,000 pounds) of oxygen.” In contrast, Hecht says, “The astronauts who spend a year on the surface will use about one metric ton between them to breathe.”

Combined with hydrogen, it might even be possible to produce water on Mars. It’s the first technology of its kind that will help future missions “live off the land”, using elements of another planet’s environment to sustain human life.

Just like its sibling, the Ingenuity helicopter, MOXIE will be subjected to a series of experiments that’ll push the envelope of its functionality. 

We’ll be holding our breath and watching what MOXIE achieves next.

Main picture: Technicians at NASA’s Jet Propulsion Laboratory lower MOXIE into the belly of the Perseverance rover. Photo credits: NASA/JPL-Caltech

By Mitchell Lim

Mitchell Lim is the latest addition to DUG’s science communication department. Currently completing his PhD in Chemical Engineering, Mitch is an expert in the fields of catalysis and ultrasonics. Full-time science geek, part-time fitness junkie, Mitch is living proof that brains and brawn are not mutually exclusive. His mission is to make science more accessible to you, while dreaming of having access to Martian land someday.