NASA has succeeded in producing oxygen on Mars

About the size of a car battery, the golden box called MOXIE for Mars Oxygen In-Situ Resource Utilization Experiment, has succeeded in producing oxygen on Mars. This historic first experiment represents the first step before considering a manned mission to the Red Planet.

NASA’s MOXIE box (credits:NASA)

In the scientific journal Science Advances, researchers from MIT detailed the results of MOXIE, which was able to produce oxygen on Mars. Several tests were carried out according to the atmospheric conditions. The machine was activated during the day, at night and during the different Martian seasons. 

Indeed, the temperatures vary during the time on Mars. We consider 4 Martian seasons as on Earth. However, these last about twice as long as on Earth because of the orbital period of 687 days (instead of about 365 days for Earth).

In each test, MOXIE produced oxygen, reaching the engineers' target of 6 grams of oxygen per hour. Although the experiment is small for now, researchers believe that a larger version of MOXIE could produce more oxygen and thus enable a manned mission to Mars. 

A mission to Mars would then take place in several stages. First, a capsule would deposit an oxygen generator. Then, a manned capsule would reach the red planet for a mission lasting several months. "We've learned a tremendous amount that will serve as a foundation for future larger-scale systems," says Michael Hecht, principal investigator of the MOXIE mission at MIT's Haystack Observatory.

MOXIE's oxygen production represents the first demonstration of a technology based on "in-situ resource utilization," or the exploitation of materials (in this case carbon dioxide) to provide sufficient resources for a mission. "This is the first demonstration of actually using resources on the surface of another planetary body, and chemically transforming them into something useful for a human mission," says Jeffrey Hoffman, MOXIE's deputy principal investigator and professor of practice in MIT's Department of Aeronautics and Astronautics. "It's historic in that sense."

NASA participated in the project through its Jet Propulsion Laboratory. NASA engineers designed Perseverance's flight software, rover integration and pre-launch testing. Despite the compromises necessary in the current MOXIE design, the instrument has shown that it can reliably and efficiently convert Mars' atmosphere into pure oxygen. 

To do this, it first draws Martian air through a filter that removes contaminants. The air is then pressurized and fed into the Solid Oxide Electrolyzer (SOXE), an instrument developed and built by OxEon Energy, which electrochemically separates the carbon dioxide-rich air into oxygen ions and carbon monoxide.

The oxygen ions are then isolated and recombined to form respirable molecular oxygen, or O2, which MOXIE then measures the amount and purity of before safely releasing it into the air, along with carbon monoxide and other atmospheric gases.

Since the rover's landing in February 2021, MOXIE engineers have turned on the instrument seven times over the course of the Martian year, each time taking a few hours to warm up, then another hour to make oxygen before shutting down. Each startup was scheduled at a different time of day or night, and in different seasons, to see if MOXIE could adapt to the planet's changing atmospheric conditions.

"Mars' atmosphere is much more variable than Earth's," Hoffman notes. "The density of the air can vary by a factor of two over the course of a year, and the temperature can vary by 100 degrees. One of the goals is to show that we can operate in all seasons." So far, MOXIE has shown that it can produce oxygen at almost any time of the day and during the Martian year.

"The only thing we haven't demonstrated is the ability to operate at dawn or dusk, when the temperature changes dramatically," Hecht says. "We have an ace up our sleeve that will allow us to do that, and once we test it in the lab, we can get to that final step to show that we can actually operate at any time."

Spring seems like the best season to produce oxygen on Mars. This is because CO2 density is highest at this time of year. 

In April 2021, the first MOXIE oxygen cycle produced 5.4 grams of oxygen in one hour. The power supply limits the potential production to 12 g/h, or about