Engineer aims to make giant leap for welding materials on the moon

(Press-News.org) Before humans can colonize the moon or Mars, scientists and engineers must first develop techniques for building permanent structures and pressurized habitats in harsh, thin-atmosphere and low-gravity environments.

Dr. Wei Li, an assistant professor of mechanical engineering in the Erik Jonsson School of Engineering and Computer Science at The University of Texas at Dallas, is developing a virtual lunar welding platform to troubleshoot assembling large structures in such conditions.

“As we try to return to the moon and reach Mars, keeping astronauts safe while achieving the missions is very important,” said Dr. Edward White, professor and department head of mechanical engineering and holder of a Jonsson School Chair. “Being in Earth’s orbit is a lot easier knowing that when things go wrong, we can make repairs and return safely. I’m really excited that Dr. Li’s research will help play an important role in making space travel safer and will enable us to successfully complete space missions.”

Li recently received an Early Stage Innovations three-year grant from NASA for up to $750,000 to support his study of welding on the surface of the moon. He was one of six researchers nationwide selected to receive the 2024 annual award, which is designed to accelerate the development of groundbreaking, high-risk/high-payoff space technologies.

“There are three main challenges for the astronauts working on the moon’s surface,” Li said. “The moon has a very thin atmosphere, so there are steep temperature changes, from around minus 387 degrees Fahrenheit to 260 degrees Fahrenheit. There is also an extreme vacuum environment due to the thin atmosphere. Finally, the gravity on the moon’s surface is only about one-sixth that of the Earth. The extreme environment can complicate the reliable implementation of building or manufacturing large structures on the moon’s surface and can lead to manufacturing defects.”

Welding metal in such an environment can cause defects that impact the material’s load-bearing capability, leading to fractures and ductile cracks; nevertheless, in-space assembly is vital to NASA’s long-term exploration goals, Li said.

“It would be very hard to establish regular machine shops on the moon’s surface to manufacture metal structures as we do on Earth,” Li said. “However, it could be possible to use spacecraft to ship metal components from the Earth to the moon, then deploy welding technology there to assemble the components into large structures that could enable the establishment of a human community.”

Li’s project will simulate lunar conditions to test the processes of electrical arc, laser and electron-beam welding in that type of environment. His virtual lunar welding platform simulates the welding process and welding-joint mechanical properties with a multiple-physics modeling approach. Among the equipment he is using is a custom-built, directed energy deposition machine, a technology typically used for additive manufacturing of metals. Li said the research also could be applied to fused deposition modeling, a type of 3D-printing process that can print nonmetallic parts in space.

Li, who directs the Comprehensive Advanced Manufacturing Lab in the Jonsson School, will work with his team to create the simulated environment at UT Dallas while working directly with NASA researchers, including Dr. Fredrick Michael from NASA’s Marshall Space Flight Center.

Li said his team will validate the simulation framework and modeling results with both space-based and on-the-ground experiments, as well as with historical experimental flight data from Skylab, the first U.S. space station. He said the model could be developed further for other space environments, including Mars and the International Space Station.

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