Making Oxygen on Mars Takes MOXIE

James Maynard
Apr 23 · 4 min read

Oxygen on Mars is one step closer to reality for future inhabitants of the Red Planet, thanks to MOXIE

The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instrument being readied for installation into the Perseverance rover. Image credit: NASA/JPL-Caltech

Oxygen on Mars is is essential for future space travelers, and a proof-of-concept experiment carried out aboard the Perseverance rover succeeded in producing a small amount of the essential gas for the first time.

The atmosphere of Mars contains about 96 percent carbon dioxide. This molecule can be converted into oxygen and carbon monoxide (a waste product) though chemical processes. However, this has never been done on another world — until now.

On April 20, The Oxygen In-Situ Resource Utilization Experiment (MOXIE), a toaster-sized instrument aboard Perseverance, separated oxygen from the tenuous carbon-dioxide-rich Martian atmosphere.

“MOXIE is a short, snappy name for a tool that helps lead to human footprints on Mars. It helps humans explore Mars by making OXygen. It works “In situ” (in place) on the Red Planet, and is an Experiment,” NASA explains.

A look at Martian exploration — today and in the future — with Dr. Kirsten Siebach and Dr. Fatima Ebrahimi. Video credit: The Cosmic Companion

Bringing air, water, and other supplies needed for life to another is prohibitively difficult and costly. Producing these essential molecules from native resources is essential to populating the Moon, Mars, and worlds beyond.

“This is a critical first step at converting carbon dioxide to oxygen on Mars. MOXIE has more work to do, but the results from this technology demonstration are full of promise as we move toward our goal of one day seeing humans on Mars. Oxygen isn’t just the stuff we breathe. Rocket propellant depends on oxygen, and future explorers will depend on producing propellant on Mars to make the trip home,” said Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate (STMD).

Fuel needs oxygen to burn, and space travel will use up significantly more oxygen than the lungs of colonists. A small human colony on Mars might use around one metric ton of breathable oxygen over the course of a year. A single rocket launch lifting four humans off the surface of Mars would require 25 metric tons of the precious element (about the mass of a space shuttle!), along with seven metric tons of fuel.

While ferrying this 25 tons of oxygen to Mars would prove prohibitively expensive, bringing a one-ton converter to the Red Planet is much easier, and efficient (once it is designed and manufactured). While MOXIE is about the size of a car battery, future instruments to extract oxygen on Mars, supporting human colonists, will need to be the size of a car.

“It’s not that simple. We’re talking about going to Mars. Living on Mars! How can I give up becoming one of the colonisers of another planet?”
Rita Carla Francesca Monticelli, Deserto rosso — Punto di non ritorno

MOXIE produced roughly five grams of oxygen on Mars during its first demonstration — enough for one person to breathe for around 10 minutes. At full operation, this instrument should be able to generate around 10 grams per hour.

Over the next Martian year (roughly two Earth years), researchers plan at least nine additional, successively-more-challenging runs of MOXIE. The instrument will be tested in various conditions, over the course of several seasons.

A cutaway look at MOXIE — the first instrument ever convert Martian atmosphere into breathable oxygen. Video credit: NASA/JPL-Caltech

Technologies like MOXIE will need to be developed to extract essential resources — like oxygen — from native materials on Mars, if we hope to, one day, live on the Red Planet.

“It’s taking regolith, the substance you find on the ground, and putting it through a processing plant, making it into a large structure, or taking carbon dioxide — the bulk of the atmosphere — and converting it into oxygen. This process allows us to convert these abundant materials into useable things: propellant, breathable air, or, combined with hydrogen, water,” Trudy Kortes, director of technology demonstrations at STMD, stated.

The conversion of carbon dioxide into oxygen can occur at temperatures around 800 C (1,470 F). MOXIE is constructed from 3D-printed nickel alloy parts, and a lightweight aerogel to hold in heat. Finally, the unit is wrapped in a thin layer of gold, reflecting infrared radiation, protecting the rest of the spacecraft from heat.

The Perseverance rover was designed to explore every aspect of Mars — including the possibility that the Red Planet once had life. Another revolutionary technology demonstration was carried out in the first test flights of Ingenuity — the first helicopter to fly on another world.

Even if evidence for ancient life on Mars is not found by Perseverance, by producing oxygen on Mars for the first time, this SUV-sized spacecraft has already helped lay the groundwork for the future human exploration of the Red Planet.

James Maynard is the founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat.

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