How NASA's Perseverance is making oxygen on Mars
One of the many pesky barriers to humans freely exploring and inhabiting Mars is the planet’s lack of oxygen. Luckily, NASA’s Perseverance rover can help.
Using an instrument dubbed MOXIE (short for Mars Oxygen In-Situ Resource Utilization Experiment), the rover successfully took carbon dioxide from the Martian atmosphere and converted it into oxygen, NASA announced on Tuesday. NASA said it plans to conduct more MOXIE tests, but did not specify when.
MOXIE ran its first test for roughly an hour, producing just under six grams of oxygen. That’s enough to keep an astronaut going for about 10 minutes, the agency explained. It won't keep someone alive for long, but it’s a key step forward in exploring Mars.
"You can imagine scaling that up and having a bigger plan for humans when we finally send them there"
Not only could that oxygen be used to allow people to breathe, but it would also lighten the load for return missions to Earth, or for trips to other parts of the solar system. Rockets need oxygen to burn fuel during liftoff. Being able to create it on Mars would mean spacecraft can bring less of it from Earth, significantly decreasing their weight. Less weight means less overall fuel needed to generate lift.
"Oxygen is the heavier part of rocket fuel," explained Michael Meyer, Mars Exploration Program lead scientist at NASA, over the phone earlier this year. If NASA wanted to get four astronauts off Mars, the spacecraft would need 27.5 tons of oxygen to do it. Keeping those four breathing for a year would require about one ton.
At the rate MOXIE is going, producing 27.5 tons would take more than 475 years. But future devices could be larger and more efficient than the 38-pound MOXIE.
"You can imagine scaling that up and having a bigger plan for humans when we finally send them there to make enough oxygen to get back off the surface and to have oxygen to breath," said Mitch Schulte, NASA's Mars 2020 program scientist.
Making oxygen on Mars
On Mars, 0.13 percent of the atmosphere is oxygen. On Earth, it's 21 percent.
"Mars' atmosphere is actually pretty thin and it's primarily composed of carbon dioxide," he said. "On Mars we don't see anything more than a tiny whiff of oxygen and that's largely from water molecules breaking apart in the atmosphere."
MOXIE takes advantage of that relative abundance of carbon dioxide, which is made up of one part carbon, two parts oxygen. An electrolyzer running at temperatures above 1,400 degrees Fahrenheit creates an electric current that separates oxygen from compressed carbon dioxide, leaving carbon monoxide waste.
MOXIE produced about six grams of oxygen per hour during its first test, with two momentary dips while it checked its parts to make sure it was running fine.
It was a bit short of its advertised rate of 10 grams per hour, but this was just the first test. NASA is always cautious when testing the rover, so it might push MOXIE harder next time.
One of Perseverance's plans on Mars is to grab samples of the Martian surface in tubes, which will be picked up by a future spacecraft and brought to Earth for study. It'll need oxygen for its takeoff from Mars. Moxie could help create that oxygen.
It could also be useful for NASA's Artemis program, currently in its early stages. The plan is to send people to the moon, and then set up a moon-to-Mars launch system.
It's not clear when NASA will launch its first manned mission to Mars. But there's a good chance MOXIE's successor will be a part of it.
