Bold Carbon Hack Could Enable Astronaut Survival on Mars

Additive manufacturing could take a big leap forward in space, as researchers reveal that carbon dioxide, the dominant component of Mars’ atmosphere, might replace expensive argon gas in printing metal parts. This shift could slash mission costs and support sustainable infrastructure on the Red Planet. The experiment, which focused on printing with 316L stainless steel, a widely used industrial alloy, found that parts made in a CO₂ environment held up surprisingly well. While not as strong as those made with argon shielding, they were significantly more cohesive than those printed in Earth’s ambient air. A Workaround for Mars’ Hostile Environment Transporting materials to Mars is a logistical nightmare, not to mention prohibitively expensive. According to a pre-print paper by Zane Mebruer and Wan Shou from the University of Arkansas, astronauts might not need to bring pressurized argon tanks with them for metal 3D printing, a technology essential to long-term planetary missions. Their research focused on a process called selective laser melting (SLM), which relies on high temperatures to fuse metal powder into solid parts. On Earth, SLM is carried out in an argon atmosphere to prevent oxidation of the metal during printing. Oxygen leads to brittleness, cracking, and reduced durability. However, argon is virtually nonexistent on Mars. That’s where the planet’s natural atmosphere, made up of more than 95% carbon dioxide, comes in as a potential substitute. Carbon Dioxide Shows Promise as a Shield Gas The research team ran multiple experiments comparing three atmospheric conditions: argon, CO₂, and ambient air. Their goal was to determine how well each gas protected the molten metal from oxidation and helped the parts retain their intended shape. While argon still performed best, achieving around 98% effectiveness in area retention, carbon dioxide followed with a solid 85%, a significant improvement over the 50% or less seen with ambient air. According to the study, one of the key findings is that carbon dioxide doesn’t oxidize the metal as aggressively as oxygen-rich air does. That’s because, despite containing oxygen atoms, CO₂ has a lower partial pressure of oxygen compared to Earth’s nitrogen-heavy air. During the laser melting process, some CO₂ dissociates under extreme heat, but the amount of reactive oxygen introduced remains low enough to avoid major damage to the forming parts. Solid Enough for Non-Critical Components Not all parts of a Mars habitat need to be perfect. While carbon dioxide–printed components showed slightly more surface roughness and lower cohesion than argon-printed ones, they were still good enough for non-critical parts, think hinges, brackets, or frames. According to the paper’s analysis, even the samples printed in argon had traces of oxygen, suggesting that some level of contamination is inevitable. Using scanning electron microscopy and energy-dispersive X-ray spectroscopy, researchers found that oxygen content in CO₂-printed parts was roughly 1.6 times higher than in those made with argon, but significantly less than in parts printed in ambient air. This difference could spell the line between functional and unusable hardware, particularly for tools or structural components that don’t require precision engineering. Potential Savings Far Beyond Mars Argon gas isn’t just rare on Mars, it’s costly on Earth, too. This research suggests that carbon dioxide could become a viable low-cost alternative for terrestrial 3D printing operations as well. According to the authors, companies might be able to cut costs on consumables by using CO₂ in cases where ultra-high quality isn’t necessary, although the rougher finish might not suit all industries. Astronauts, though, won’t care much about aesthetics. If a tool holds together and gets the job done, it’s a win, especially when Earth is nine months away. Printing directly in the Martian atmosphere would also reduce equipment complexity and reliance on pressurized chambers, a major step toward autonomous, in-situ manufacturing on other worlds.