Evrim Yazgin
Cosmos science journalist
NASA’s Perseverance Mars rover has generated oxygen on Mars for the 16th and final time with the agency saying it exceeded expectations.
A device on the rover is known as MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment).
Since Perseverance first landed on Mars in 2021, MOXIE has generated 122 grams of oxygen. According to a NASA blog post about the success of MOXIE’s mission, this is about the amount a small dog breathes in 10 hours. Its 16th run on August 7 saw the microwave-sized device produce 9.8 grams of breathable oxygen.
When functioning most efficiently, MOXIE was able to produce 12 grams of more than 98% purity oxygen an hour. This was double what NASA had hoped for the experiment.
MOXIE successfully completed all technical requirements and produced oxygen under different conditions and throughout the Martian year.
In September last year, MOXIE reached the milestone of converting 100 minutes-worth of oxygen.
According to NASA, the average person needs about 0.84 kg of O2 per day, meaning MOXIE has produced enough oxygen in a little more than 2 years to keep a person alive on Mars for about 3.5 hours. A full full-scale MOXIE for a team of Martian explorers would need to produce about 2–3 kg of oxygen per hour. As a proof of concept, though, MOXIE has been a resounding success.
“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,” says NASA Deputy Administrator Pam Melroy. “Developing technologies that let us use resources on the Moon and Mars is critical to build a long-term lunar presence, create a robust lunar economy, and allow us to support an initial human exploration campaign to Mars.”
After filtering out contaminants in the Martian atmosphere, MOXIE turns the CO2-rich air through a multi-step process. First, the air is pressurised and heated to 800°C. It is then passed through an electrolyser which uses catalysts to split the CO2 in the air into oxygen ions (charged oxygen atoms) and carbon monoxide (CO).
Finally, electricity is used to recombine the oxygen ions into breathable O2.
Unlike many other experiments aboard Perseverance, MOXIE is not focused on primary science goals, but future human exploration. It is the first demonstration that human life could be supported on the Red Planet.
Rather than bringing huge amounts of oxygen with them, MOXIE shows that astronauts can breathe easy knowing their oxygen can be produced on Mars. This is an example of in-situ resource utilisation (ISRU).
“MOXIE has clearly served as inspiration to the ISRU community,” says MIT’s Michael Hecht, principal investigator for the instrument. “It showed NASA is willing to invest in these kinds of future technologies. And it has been a flagship that has influenced the exciting industry of space resources.”
While the experiment has also shown Hecht and his team how to make a more efficient version of MOXIE, the next step is to create a full-scale system that includes a way to liquefy and store the produced oxygen.
