NASA's Perseverance rover is reliably producing oxygen. A scaled-up version could help astronauts breathe on Mars one day.

• A toaster-sized device called MOXIE is tucked inside NASA's Perseverance rover, which landed on Mars in 2021.
• MOXIE reliably produces 6 grams of oxygen per hour under various conditions on Mars.

Inside NASA's Perseverance rover sits a boxy, toaster-sized instrument.

The contraption, called MOXIE, has been successfully brewing up oxygen on Mars — a necessary requirement for sustainably working on and departing the red planet.

Researchers tested the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), seven times in 2021, during nighttime, daytime, and in different Martian seasons, according to a study published Wednesday in Science Advances.

In each run, it produced about 6 grams of oxygen per hour — about the oxygen production rate of a small tree on Earth.

Researchers' primary goal was to demonstrate that the device will work reliably, predictably, and robustly over and over again, Michael Hecht, principal investigator of the MOXIE mission at MIT's Haystack Observatory, told Insider.

"The answer, to all those things, is yes," Hecht said, adding, "That's a big deal."

That technology could allow Mars explorers to breathe on the red plant one day. If a next-generation device is able to produce oxygen on a larger scale, that oxygen could be used as a component in the rocket fuel needed to bring a crew back 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," Jeffrey Hoffman, MOXIE deputy principal investigator, said in a press release. "It's historic in that sense."

Carbon dioxide makes up 96% of Mars' atmosphere. MOXIE works by taking carbon dioxide from the atmosphere, running it through a fuel cell, and heating it to 1,470 degrees Fahrenheit, according to Hecht. Then, MOXIE zaps the molecules with electricity to strip them of their oxygen atoms. The oxygen atoms then combine with each other to produce oxygen gas.

"I like to say that we're making oxygen out of thin air because the air is very, very, very thin," Hecht said, adding, "It's like being at 100,000 feet above the surface of Earth."

According to Hecht, the MOXIE team faced challenges when designing a device capable of producing oxygen in the Martian environment.

"Mars is hard," Hecht said, adding, "First of all, you have to make something that is going to go through all kinds of abuse, before it even gets to Mars."

In addition to having to withstand the harsh vacuum and radiation of space, MOXIE needed to be small — about the size of a toaster — in order to fit aboard the Perseverance rover.

Still, Hecht said MOXIE proved its mettle. "We set our own record with making 10.4 grams of oxygen in a brief excursion," Hecht said, adding that the device was designed to produce 6 grams of oxygen per hour.

"We've pushed the instrument as hard as we're likely to ever push it, and that was a real accomplishment," he said.

MOXIE splits carbon dioxide into carbon monoxide and oxygen atoms, before the single oxygen atoms combine to make breathable oxygen.

Since January, the team has run the experiment every month or so. The oxygen-generating machine has now been used a total of 11 times. That's allowed them to troubleshoot, including running the device more safely by keeping it at a fixed voltage.

"When the voltage gets too high for the given conditions, that gets us into trouble," Hecht said, adding, "Instead of making carbon monoxide, we start making carbon and that just gums up the works and poisons the instrument — it's game over."

Since the Perseverance rover landed on Mars on February 18, 2021, it's captured snapshots of the rusty red surface, sampled rocks, and taken selfies.

MOXIE first proved it could generate oxygen out of Martian air in April 2021. The new research was meant to test whether the device could consistently generate oxygen on the red planet. Researchers also wanted to learn how to make MOXIE's descendants robust enough to support future human exploration on Mars.

"We're doing this to inform that future MOXIE, which is the one that really counts," Hecht said.

Researchers imagine a jumbo version of MOXIE, approximately 100 times larger, could produce oxygen at the same rate as several hundred trees.

Hecht said scaling up the technology shouldn't be too challenging. Now that MOXIE has proved we can reliably produce oxygen on another planet, Hecht and his team hope future Mars mission will include a larger-scale version of its technology.

"This is very good news for the prospect of sending people to Mars and being self-sufficient," he said.