The experiment, which is part of NASA Mission Rover of Perseverance which landed on Mars in February 2021, is the first time resources from another planet have been turned into something useful for human missions, researchers have said. The little box, created by NASA’s Jet Propulsion Laboratory and MIT, produces enough oxygen to match the production of a small tree on Earth, and can do so day or night for several Martian seasons.
“That’s what explorers have been doing since time immemorial,” said Jeffrey Hoffman, former NASA astronaut, deputy principal investigator of the MOXIE mission and professor of aerospace engineering at MIT. “Find out what resources are available where you are going and find out how to use them.”
Space agencies, scientists and entrepreneurs are clamoring for humans to explore Mars. NASA’s highly anticipated and troubled Artemis mission to the moon is seen as a stepping stone to Mars exploration over the next decade. China hopes to put humans on the planet by 2033. Elon Musk, the richest person in the world and CEO of SpaceX, hinted that he would 2029.
But getting humans to Mars requires several complicated things, Hoffman said. Astronauts must endure high levels of cosmic radiation during the long journey to the planet. Traveling to and from Mars can take more than 8 months, so there must be enough food and medicine for space travelers.
Perhaps the most important thing is a reliable supply of oxygen, Hoffman said. Astronauts need it to breathe in any temporary habitat they set up on Mars, as well as in spacesuit tanks as they explore the planet. It is also a crucial propellant to power the rocket they would need to return from Mars to Earth.
Space agencies could send enough oxygen to Mars for astronauts to breathe and make the return trip, Hoffman said, but that would be very expensive, as it would require multiple rocket launches. Making oxygen on Mars from carbon dioxide in its atmosphere would be cheaper, he said. The atmosphere of Mars is made up of approximately 96% carbon dioxide.
To test their ability to convert carbon dioxide into oxygen, NASA brought a small golden box on its Perseverance Rover mission last year. Since April 2021, MOXIE has performed several tests in which it produced oxygen at different times of the Martian day and under different seasonal conditions. During each experiment, the box created about 6 grams of oxygen per hour, equivalent to the production of a modest tree on Earth. (In his most recent test, which will be published in a future article, Hoffman said the machine’s output increased to 10 grams per hour.)
If the technology is mastered, scientists will have to significantly increase the size of the machine and ensure that it can operate continuously. To sustain a human mission to Mars and bring people back, Hoffman said, at least 4.5 to 6.5 pounds of oxygen would need to be created per hour during a multi-year mission. “That would require multiplying things by several hundred,” he said.
The machine can operate for most of the Martian day except for a few specific hours.
“The only thing we haven’t demonstrated is running at dawn or dusk, when the temperature [on Mars] changes dramatically,” said Michael Hecht, principal investigator of the MOXIE mission at MIT’s Haystack Observatory. “We have an ace up our sleeve that will allow us to do that, and once we’ve tested it in the lab, we can reach that final milestone to show that we can really race anytime.”
Engineers plan to push the MOXIE device to its limits, increasing its oxygen-producing capacity and ensuring it operates during the Martian spring, when the planet’s atmosphere is dense and dioxide levels of carbon are high. “We’ll put everything as high as we dare and let it run for as long as we can,” Hecht said.
Engineers will monitor the machine for wear and see if it can withstand enough stress to suggest it can be converted into a full-scale system that can operate continuously for thousands of hours. If so, the effects could be significant.
“To support a human mission to Mars, we need to bring a lot of stuff from Earth,” Hoffman said. “But dumb old oxygen? If you can make it, go for it, you’re ahead of the game.