Exploring Metal Additive Manufacturing in Martian Atmospheric Environments

TL;DR

This paper explores the use of Martian atmospheric CO2 as a shielding gas in selective laser melting to enable sustainable in-space manufacturing of metallic parts on Mars, comparing it with argon and air environments.

Contribution

It demonstrates the feasibility of using CO2 as a substitute for argon in SLM, highlighting the process parameters needed for quality fabrication in Martian conditions.

Findings

CO2 environment produces acceptable part quality with slightly inferior surface finish and oxidation resistance compared to argon.

Parts fabricated in CO2 outperform those made in ambient air in terms of cohesion and oxidation.

Balanced process parameters are crucial for maintaining thermal equilibrium during SLM in different atmospheres.

Abstract

In-space manufacturing is essential for achieving long-term planetary colonization, particularly on Mars, where material transport from Earth is both costly and logistically restrictive. Traditional subtractive manufacturing methods are highly equipment-, energy-, and material-intensive, making additive manufacturing (AM) a more practical and sustainable alternative for extraterrestrial production. Among various AM technologies, selective laser melting (SLM) stands out due to its exceptional versatility, precision, and capability to produce dense metallic parts with complex geometries. However, conventional SLM processes rely heavily on inert argon environments to prevent oxidation and ensure high-quality part formation, conditions that are difficult to reproduce on Mars. This study investigates the feasibility of using carbon dioxide (CO2), which makes up over 95% of the Martian atmosphere, as a potential substitute for argon in SLM. Single-track and two-dimensional 316L stainless steel specimens were fabricated under argon, CO2, and ambient air environments with a wide range of laser parameters to evaluate the influence of atmospheric composition on surface morphology, microstructural cohesion, and oxidation behavior. The results reveal that no single parameter controls the overall part quality; rather, a balance of parameters is essential to maintain thermal equilibrium during fabrication. Although parts produced in CO2 exhibited slightly inferior surface finish, cohesion, and oxidation resistance compared to argon, they performed significantly better than those fabricated in ambient air. These findings suggest that CO2-assisted SLM could enable sustainable in situ manufacturing on Mars and may also serve as a cost-effective alternative shielding gas for terrestrial applications.