Humans are one small step closer to landing on the red planet.

The Mars In Situ Oxygen Resource Utilization Experiment, better known as MOXIE, successfully produced oxygen from the carbon dioxide-rich atmosphere of Mars in a series of tests as part from NASA’s Perseverance mission, which landed on Mars in February 2021.

MOXIE was able to produce oxygen in seven tests conducted since April 2021, in a variety of atmospheric conditions, including during the planet’s day and night, and across different Martian seasons, according to research published Wednesday in the journal Science Advances. .

(Like Earth, Mars has distinct seasons, but they last longer than the seasons here on Earth, since Mars takes longer to orbit the Sun, according to NASA).

In each of the tests, MOXIE met its goal of producing six grams of oxygen per hour, about the rate of a modest tree on Earth.

“This is the first demonstration of resource utilization on the surface of another planetary body and its chemical transformation into something useful for a human mission,” said MOXIE Deputy Principal Investigator Jeffrey Hoffman, a retired astronaut and professor in the department. of aeronautics and astronautics from the Massachusetts Institute of Technology, in a press release.

“It’s historic in that sense.”

MOXIE is small, about the size of a toaster, so it can fit aboard the Perseverance rover. It is designed to run for short periods, starting up and shutting down at each test, to align with the rover’s exploration schedule and other mission responsibilities.

An expanded MOXIE would include larger units that could run continuously and be sent to Mars before a human mission to produce oxygen at the rate of several hundred trees. This would make it possible to generate, and store, enough oxygen to support humans once they arrive and fuel a rocket for returning astronauts to Earth.

According to the researchers, the constant production of MOXIE since its arrival on Mars is a promising first step towards that goal, although further adjustments are needed to ensure it can work at sunrise and sunset, times when the planet’s temperature changes substantially. said Michael Hecht, principal investigator for the MOXIE mission at MIT’s Haystack Observatory.

How MOXIE works

The thin Martian atmosphere is 96% carbon dioxide, which doesn’t help oxygen-breathing humans much.

In addition, it is much more variable than the Earth’s atmosphere. “Air density can vary by a factor of two throughout the year, and temperature can vary by 100°F,” Hoffman said. “One of the goals is to show that we can make (MOXIE) work on all stations.”

MOXIE works by splitting carbon dioxide molecules, which are made up of one carbon and two oxygen atoms, hence its chemical formula CO2. MOXIE breaks apart oxygen molecules and emits carbon monoxide as a waste product.

Engineers continue to test MOXIE. They plan to expand their capacity and increase their production, focusing on the Martian spring months, when, according to the researchers, atmospheric density and carbon dioxide levels are particularly high.

“The next test will be during the highest density of the year, and we want to produce as much oxygen as possible,” Hecht said. “We’ll put it as high as we dare and let it run as long as possible.”

MOXIE also appears to be resistant. It has worked successfully despite having to be repeatedly powered on and off for testing, a thermal stress that can degrade the system over time. This would suggest that a large-scale system designed to run continuously could do so for thousands of hours, according to the MIT press release.

“To support a human mission to Mars, we have to bring back a lot of things from Earth, like computers, spacesuits and habitats,” Hoffman said in the statement. “But silly old oxygen? If you can make it there, go for it… you’re way ahead of the curve.”