‘Historic’ box on Mars that makes oxygen at the speed of one tree

When NASA’s Perseverance robot flew to Mars last year, it brought with it a small, gold box called MOXIE for the Mars Oxygen In-Situ Resource Utilization Experiment.

Since then, MOXIE has been making oxygen from thin Martian air.

And on Wednesday in the journal Science Advances, the team behind this device confirmed that MOXIE has worked so well that its oxygen output is comparable to the rate of a modest output of an Earth tree.

By the end of 2021, extensive data showed that MOXIE successfully achieved the target oxygen delivery of six grams per hour during seven separate experimental runs and in various atmospheric conditions. That includes day and night, different Martian seasons and other things like that.

“The only thing we haven’t shown is running at dawn or dusk, when the temperature changes significantly,” Michael Hecht, principal investigator of the MOXIE mission at the Massachusetts Institute of Technology’s Haystack Observatory, said in a press release. “We have an asset in store that allows us to do that, and once we test that in the lab, we can hit that final milestone to show that we can really run any moment.”

A schematic showing where Moxie is on NASA's Mars rover.  There are a total of six wheels on the rover, three on each side, and Moxie is facing the far right wheel on the right in the image.

Here is MOXIE on the Mars rover.


For scientists and space agencies alike, it’s especially exciting that MOXIE’s promise remains strong, as proposed timelines for astronaut-laden Mars expeditions have looming deadlines for learning how to keep future space explorers safe on the red planet.

For example, SpaceX CEO Elon Musk’s goal of landing humans on Mars appears to be 2029, and NASA’s upcoming Artemis I moon mission is intended to pave the way for Mars excursions planned for the 2030s or 2040s. “To support a human mission to Mars, we need to take a lot of stuff from Earth, such as computers, spacesuits and habitats” Jeffrey Hoffman, MOXIE’s deputy principal investigator and a professor at MIT, said in a press release. “But stupid old oxygen? If you can make it, go for it — you’re way ahead of the game.”

As it stands, MOXIE is super small (it’s actually the size of a toaster), but this is potentially a good thing. It means that if scientists can somehow increase the size of the patterned cube, MOXIE could make much more than just six grams of oxygen per hour.

“We’ve learned a tremendous amount that will inform future systems on a larger scale,” Hecht said.

Perhaps one day, the researchers say, it could eventually produce oxygen at the rate of several hundred trees, supporting astronauts once they arrive on Mars and fueling rockets that need the life-giving element to get the crew back to Earth. to bring.

“Astronauts who spend a year on the surface may use one ton between them,” Hecht said in a NASA press release last year. But, according to the space agency, getting four astronauts off the Martian surface for a future mission would require about 15,000 pounds (7 metric tons) of rocket fuel and 55,000 pounds (25 metric tons) of oxygen. Getting all that oxygen from Earth would be super expensive and inefficient.

So, as Hoffman says, why not just make all the oxygen on the arid planet itself?

How does MOXIE work?

On Mars, MOXIE actively converts carbon dioxide in the Martian atmosphere – where the element makes up a whopping 96% – into breathable oxygen.

A bit of chemistry 101 is that carbon dioxide molecules are made up of one carbon atom and two oxygen atoms. Those pieces are actually stuck together. But an instrument within MOXIE called the Solid Oxide Electrolyzer can collect the oxygen bits in those CO2 molecules that scientists are interested in. Once completed, all the free-floating oxygen species recombine into O2, or molecules with two oxygen atoms, otherwise known as the kind of oxygen we know and love.

I know it’s different, but I keep thinking about Pixar’s WALL-E doing this. So, as WALL-E would say: Ta-da!

In what looks like a lab cleanroom, we can see the gold, patterned Moxie mechanism attached to wires and other metal devices holding it up.

Technicians from NASA’s Jet Propulsion Laboratory lower the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instrument into the belly of the Perseverance rover.


“This is the first demonstration of actually using resources on the surface of another planetary body and chemically transforming them into something that would be useful for a human mission,” Hoffman said. “In that sense, it’s historic.”

Along the way, this process requires the use of super-high heat — reaching temperatures of about 1,470 degrees Fahrenheit (800 Celsius) — which is fascinating what gives MOXIE its characteristic gold coating.

As with NASA’s pioneering James Webb Space Telescope, MOXIE must be shielded from infrared heat because it uses heat itself. A gold coating does just that, and in fact the JWST’s mirrors are also coated in gold for the exact reason.


A wing of the main mirror of the James Webb Space Telescope opens in place during a final test of the mirror system in May 2021. Look at that gilded beauty.


Next, the MOXIE team wants to show that MOXIE works well under even more intense conditions, such as a next run that will take place during the “highest density of the year,” Hecht said. “We set everything as high as we dare, and let it run for as long as possible.”

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