How Astronauts Will Fix Their Gear Using Thin Air

By Andy Tomaswick - January 16, 2026 12:43 PM UTC | Missions
Samples of the 3D printed metal using the three different shield gases. Credit - Z. Mebruer & W. Shou
Samples of the 3D printed metal using the three different shield gases. Credit - Z. Mebruer & W. Shou

Additive Manufacturing, more commonly known as 3D printing, will be an absolutely critical technology for any long-term settlement on another world. Its ability to take a generic input, such as plastic strips or metal powder, and turn it into any shape of tool an astronaut will need is an absolute game changer. But the chemistry behind these technologies is complicated, and their applications are extremely varied, ranging from creating bricks for settlements to plastics for everything from cups to toothbrush holders. A new paper available in pre-print on arXiv from Zane Mebruer and Wan Shou of the University of Arkansas, explores one specific aspect of a particularly important type of 3D printing, and realized that they could save millions of dollars on Mars missions by simply using the planet’s atmosphere to help print metal parts.

Their study focused on one critical component of a type of metal 3D printing process known as selective laser melting (SLM) which is used to print 316L stainless steel - the workhorse material of many industries. In Earth’s atmosphere, the oxygen that makes up a large percentage of our atmosphere actively oxidizes the material being printed, making the end product brittle and prone to falling apart. To combat this oxidation, 3D printers use something called a “shield gas” to exclude air and its disruptive oxygen from the general area surrounding the print.

Typically, this shield gas is Argon - an inert noble gas that doesn’t really react with much. However, it is expensive, even on Earth, and almost completely lacking on Mars. For mission planners, that means, if astronauts were expected to utilize SLM, they would need to import Argon from Earth, with all the costs that transporting a tank of pressurized gas entails. But the new paper describes a different way - using Mars’ atmosphere as the shield gas.

Fraser discusses how we can live off the land on Mars.

At first glance, that might seem counterintuitive. Mars’ atmosphere is primarily composed of carbon dioxide, which, as the name suggests, has oxygen in it. Since the whole purpose of a shield gas is to keep oxygen away, wouldn’t a gas that contains the potentially oxidizing component be a non-starter?

Surprisingly, the answer seems to be no. The paper describes a series of experiments the authors ran using Argon, CO2, and ambient Earth air on a series of SLM printed parts. While the CO2 didn’t perform as well as the Argon, it was acceptable enough for use in a wide variety of non-critical metal infrastructure parts, like hinges or door handles. In one particular test, where they attempted to print solid square layers, for example, Argon was the best with around 98% effectiveness at holding its shape, whereas carbon dioxide had around 85% “area retention”. Ambient air, in contrast, was less than 50%, essentially making the parts produced under it useless, as expected.

So why does this work? Carbon dioxide dissociates at the high temperatures associated with the laser melt pool being used to bond the metal together. That means reactive O2 is actively being added to the system. However, the partial pressure of oxygen in a pure CO2 environment is actually less than the pressure pushing the oxygen down in the nitrogen-rich atmosphere on Earth. So while there is some oxygen in the general area, it's not being as actively forced into the melt pool where it can do its oxidative damage.

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The authors studied part samples made as an output of their experiment and found that even the parts printed in Argon had some oxygen content. Parts printed with oxygen had about 1.6 times as much oxygen content, but still significantly less than the parts printed in ambient air, and that seems to make all the difference in terms of their functional usefulness.

This work has implications even outside of space exploration. Argon is expensive no matter where you get it, so the idea that you can use a much cheaper substitute (CO2) shield gas and get “good enough” results could save metal 3D printing companies a lot of money in consumable costs. Whether or not they’d be willing to take the hit to their brand reputation from the notably less visually appealing prints is a different question.

But guess who doesn’t care about what parts aesthetically look like as long as they work? Astronauts on a planet 9 months of travel time away from the nearest door handle manufacturer. Simply setting up a printer outside of their hab to use the atmosphere of the planet that would otherwise be trying to kill them seems like an effective way to perform a small bit of in-situ resource utilization. Hopefully that work brings the reality of a long-term settlement on Mars even one tiny step closer.

Learn More:

Z. Mebruer & W. Shou - Exploring Metal Additive Manufacturing in Martian Atmospheric Environments

UT - Mars Rocks Have the Right raw Ingredients to 3D Print Everything From Tools to Rocket Parts

UT - Metal Part 3D Printed in Space for the First Time

UT - Don't Take Batteries to the Moon or Mars, 3D Print Them When you Get There

Andy Tomaswick

Andy Tomaswick

Andy has been interested in space exploration ever since reading Pale Blue Dot in middle school. An engineer by training, he likes to focus on the practical challenges of space exploration, whether that's getting rid of perchlorates on Mars or making ultra-smooth mirrors to capture ever clearer data. When not writing or engineering things he can be found entertaining his wife, four children, six cats, and two dogs, or running in circles to stay in shape.