MIT's MOXIE takes a huge step toward human life on Mars with oxygen production

In a significant breakthrough, the Massachusetts Institute of Technology's (MIT) lunchbox-sized machine has been producing oxygen from the Red Planet's atmosphere for more than a year, giving hope of life on Mars one day.

Since April 2021, the MIT-led Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) successfully made oxygen from the Red Planet's carbon-dioxide-rich atmosphere, according to a press release published by the institute on Wednesday.

"It's historic," said MOXIE's deputy principal investigator Jeffrey Hoffman, a professor of the practice in MIT's Department of Aeronautics and Astronautics.

"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."

On seven experimental runs, MOXIE produced oxygen in various atmospheric conditions, including during the day and night and throughout the Martian seasons.

In each run, the instrument produced six grams of oxygen per hour, which is about the rate of a small tree on Earth.

MOXIE's oxygen production on Mars also represents the first demonstration of "in-situ resource utilization," the idea of harvesting carbon dioxide on Mars to make oxygen that would otherwise have to be transported from Earth.

The oxygen machine was parceled aboard NASA's Perseverance rover and Mars 2020 mission.

How does MOXIE work?

MOXIE has demonstrated that, despite the inevitable trade-offs in its current architecture, it can reliably and effectively convert Mars' atmosphere into pure oxygen.

To do this, it draws in Martian air and passes through a filter to remove any impurities. The Solid OXide Electrolyzer (SOXE) is a device created and manufactured by OxEon Energy, and the compressed air is split into oxygen ions and carbon monoxide by electrochemical reactions.

The oxygen ions are then separated and united again to create breathable molecular oxygen, or O2, which MOXIE then analyzes for quantity and purity before harmlessly releasing it back into the atmosphere with carbon monoxide and other atmospheric gasses.

The instrument has demonstrated its ability to produce oxygen practically year-round on Mars.

"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."

The game plan

MOXIE's current design is small to fit aboard the Perseverance rover. It is built to run for short periods, starting up and shutting down with each run, depending on the rover's exploration schedule and mission responsibilities.

According to MIT researchers, a scaled-up version of MOXIE could be sent to Mars ahead of a human mission to continuously produce oxygen at the rate of hundreds of trees.

At this capacity, the system should produce enough oxygen to sustain humans once they arrive and power a rocket that will return astronauts to Earth.

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

Engineers intend to enhance MOXIE's production capacity as it continues to produce oxygen on Mars, especially in 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," said Hecht.

"So we'll set everything as high as we dare and let it run as long as we can."

As one of many experiments on the Perseverance rover, MOXIE cannot operate continually as a natural system would.

Instead, the instrument must start up and shut down after every run, putting heat stress on the system that could eventually cause it to fail.

Suppose MOXIE can function properly despite switching on and off frequently. In that case, a more extensive system that is intended to run continuously might be able to do the same 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 Hoffman.

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

This research, supported, in part, by NASA, was first published in Science Advances.

Study abstract:

MOXIE [Mars Oxygen In Situ Resource Utilization (ISRU) Experiment] is the first demonstration of ISRU on another planet, producing oxygen by solid oxide electrolysis of carbon dioxide in the martian atmosphere. A scaled-up MOXIE would contribute to sustainable human exploration of Mars by producing on-site the tens of tons of oxygen required for a rocket to transport astronauts off the surface of Mars, instead of having to launch hundreds of tons of material from Earth’s surface to transport the required oxygen to Mars. MOXIE has produced oxygen seven times between landing in February 2021 and the end of 2021 and will continue to demonstrate oxygen production during night and day throughout all martian seasons. This paper reviews what MOXIE has accomplished and the implications for larger-scale oxygen-producing systems.