A Briefcase-Sized Box Is Already Making Oxygen on Mars

Currently, the Martian atmosphere is in no way hospitable to Earthlings. It is formed primarily of carbon dioxide and is over 100 times less dense than Earth's atmosphere. It would soon stop breathing completely for any individuals who tried to breathe in it.

A modest device, about the size of a suitcase, has been consistently extracting breathable oxygen from the Martian atmosphere on that sandy, arid, alien world.

In order to manufacture breathing air for a human expedition to the red planet, it is the first demonstration of the processing of in situ resources for human use on another world.

Its name is MOXIE (Mars Oxygen In-Situ Resource Utilization (ISRU) Experiment), and it is a device that utilizes electrolysis to separate Martian carbon dioxide into carbon monoxide and oxygen. It is mounted inside NASA's Perseverance rover.

According to the researchers, MOXIE produced oxygen seven times as much between February 2021, when Perseverance arrived, until the end of 2021.

According to former NASA astronaut and MOXIE deputy principle investigator Jeffrey Hoffman of MIT, "This is the first demonstration of actually exploiting resources on the surface of another planetary body, and changing them chemically into something that would be usable for a human mission."

It is not novel to produce oxygen by electrolysis. For instance, the International Space Station makes additional breathing air by electrolyzing water to separate it into hydrogen and oxygen.

If there is another technique, water on Mars might be too valuable to be used in this way.

Fortunately, oxygen is a part of many substances, including carbon dioxide, which is a molecule made up of one carbon and two oxygen atoms and makes up about 96 percent of the atmosphere on Mars.

The difficulty lay in creating a device here on Earth that could perform the electrochemical reduction of carbon dioxide into its component elements on Mars using the available ingredients.

It first pulls in Martian air and scrubs it with a filter. The Solid Oxide Electrolyzer is subsequently used to compress, heat, and send this cleansed Mars air (SOXE). The electrolyzer converts carbon dioxide into oxygen ions and carbon monoxide, which is released back into the Martian environment.

In order to determine its quantity and purity, the oxygen ions are then united once more to form O2, or molecular oxygen, which is subsequently released back into the atmosphere.

Scientists have found that this procedure consistently produced oxygen that can be breathed in. It operates for one hour per experiment after several hours of warming up, followed by a time of powering down. The maximum amount of oxygen MOXIE is designed to produce in one hour of operation is 10 grams, or about 20 minutes' worth of oxygen for one astronaut.

For a total of 49.9 grams of molecular oxygen, MOXIE generated between 5.4 and 8.9 grams in each of its seven runs.

MOXIE must be able to operate in a wide range of temperatures and air densities since Mars has extremely changeable air density and temperature, not just from day to night but also during the shifting seasons of the year.

Throughout its seven runs, MOXIE was successful in producing oxygen in a range of situations, including during the day, at night, and at all times of the year.

According to MOXIE project leader Michael Hecht of MIT's Haystack Observatory, "the only thing we haven't proved is running at dawn or dusk, when the temperature is changing significantly.

We do have a trick up our sleeves that will enable us to do that, and after we test it in the lab, we can accomplish that last goal to demonstrate that we can actually run at any time.

Naturally, the ideal situation would have a continuous life support system, as individuals require air to breathe. Additionally, it will have to be much larger than MOXIE: Hecht estimated last year that a small crew of astronauts would need about one metric ton of breathing oxygen for their whole year on Mars.

The crew anticipated that the voyage would take 500 tons of oxygen in total, not counting the oxygen needed for the propellant for the return trip.

The creation of this broader system will be influenced by what the team has learned over the first year of MOXIE's activities. But there is still work to be done.

The season of the year when the atmosphere is the densest will be used for the next trial run. Then, according to the researchers, they will exert as much pressure as possible on the instrument to see how much oxygen it can produce.

This will not only illustrate MOXIE's capabilities but also its limitations, allowing engineers to create a stronger device for the upcoming crewed expedition to Mars.

And that will resolve a big piece of the riddle involved in not just assuring humans' safe return home but also making an inhabitable location more hospitable.

"We have to transport a lot of stuff from Earth, like computers, spacesuits, and housing, to enable a human voyage to Mars," Hoffman claims.

"But dreadful old oxygen? Go for it if you can get there; you'll be miles ahead of the competition."

Science Advances has published the research.