Experimental Device MOXIE Demonstrates Feasibility of Extracting Oxygen From Mars’ Atmosphere
An experiment conducted on Mars has successfully demonstrated the capability of extracting breathable oxygen from the planet’s thin atmosphere, according to NASA. The Mars Oxygen In-Situ Resource Utilization (ISRU) Experiment, also known as MOXIE, has been operating aboard NASA’s Perseverance rover and has continuously broken apart molecules in the Martian air to generate a steady supply of oxygen.
Now, after completing its mission, MOXIE is set to retire. “MOXIE’s impressive performance shows that it is feasible to extract oxygen from Mars’ atmosphere – oxygen that could help supply breathable air or rocket propellant to future astronauts,” stated NASA Deputy Administrator Pam Melroy. She emphasized the significance of developing technologies that utilize resources on celestial bodies such as the Moon and Mars to establish a long-term presence in space and support human exploration missions.
Designed by scientists at the Massachusetts Institute of Technology (MIT), the MOXIE experiment has been in operation since Perseverance’s landing on Mars in February 2021. Researchers on Earth have sent commands to MOXIE to test its functionality under various Martian conditions. During 16 runs, the experiment has produced a total of 122 grams of oxygen, which NASA estimates would be sufficient to sustain a small dog for 10 hours or a human for 4 hours.
MOXIE employs electrolysis to break down carbon dioxide into its constituent atoms. The device first draws in Martian air and purifies it through a filtering process. The purified air is then compressed, heated, and sent through the Solid OXide Electrolyzer, where the carbon dioxide is converted into carbon monoxide and oxygen ions. The carbon monoxide is released into the atmosphere, while the oxygen atoms are recombined into molecular oxygen (O2), which is essential for human survival. The quantity and purity of the oxygen produced are measured before it is released back into the Martian atmosphere.
Each MOXIE run takes a few hours to complete. After a warm-up period, the experiment collects oxygen for one hour before powering down. Within this hour, MOXIE is designed to generate up to 10 grams of breathable oxygen, equivalent to roughly 20 minutes of oxygen supply for one astronaut. The actual amount of oxygen produced varies, but on the 16th run conducted on August 7th, MOXIE successfully extracted approximately 9.8 grams of breathable oxygen, closely approaching its target.
Even in a worst-case scenario, MOXIE and similar devices could supplement other oxygen supplies, reducing the amount of cargo required to be transported from Earth. However, leveraging the knowledge gained from MOXIE, researchers, led by MIT physicist and MOXIE principal investigator Michael Hecht, believe they can develop a comprehensive system that includes an improved version of the oxygen-extracting device, a method for liquefying the oxygen gas, and a means of storing the liquid oxygen.
Considering the oxygen requirements for a team of astronauts living on Mars for an extended duration and the propellant needs for spacecraft, approximately 500 metric tons of oxygen would be necessary for future Martian missions. However, numerous challenges must be addressed and resolved before humans embark on a long-term stay on the red planet, with oxygen being just one of many obstacles.
“We have to make decisions about which things need to be validated on Mars,” remarked Michael Hecht. “I think there are many technologies on that list; I’m very pleased MOXIE was first.” Hecht’s remarks highlight the need to prioritize and validate key technologies before undertaking ambitious missions to Mars.
A paper detailing MOXIE’s initial seven runs was published in Science Advances last year, shedding light on the experiment’s early findings and progress.