Research Progress of Metal Additive Manufacturing Technology and Application in Space: A Review

Metal additive manufacturing in space is a cutting-edge technology that is designed to meet the needs of space exploration and space station construction. This technology is capable of customizing and repairing key metallic parts in a space microgravity environment, providing the feasibility for long-term space tasks. It enables astronauts to perform on-site repairs and replace broken parts, significantly reducing the risk of mission failure on the International Space Station or during future deep space missions. Further, this technique opens new possibilities for constructing space bases by directly utilizing the materials from space, thereby reducing reliance on Earth’s resources. However, metal additive manufacturing in space faces challenges due to the unclear underlying mechanisms that lie in (I) the significant differences in the melting behaviors of materials in a space microgravity environment compared to those on Earth; and (II) extreme environmental factors, i.e., radiation and temperature fluctuations, that influence the metal additive manufacturing process and, consequently, the properties of the manufactured materials. This review provides a comprehensive analysis of those mechanisms underlying metal additive manufacturing in space, based on published works. Emphasis is placed on aluminum, titanium, iron, and copper-based metals. Our work may offer valuable guidance for reducing mission costs, improving safety, and enabling the on-demand production of complex components in the harsh environment of space by using metal additive manufacturing.