Researcher Advances Lunar Welding With NASA Award

High-Risk/High-Payoff Technology Addresses In-Space Assembly

Living outside of the Earth’s atmosphere on Mars or the surface of the moon may become a reality one day, but first scientists need to overcome structural barriers. To house people and other organisms, permanent structures like towers and pressurized habitats must be constructed in harsh, 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 environments.

“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 head of the Department of Mechanical Engineering. “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 has recently received an Early Stage Innovations (ESI) award from NASA for up to $750,000 to support his study of lunar welding on the surface of the moon for three years. In late 2024, Li was one of just six researchers nationwide selected to receive the grant, awarded 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 40 degrees Kelvin to 400 degrees Kelvin, or around -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 of the Earth’s gravity. The extreme environment can complicate the reliable implementation of building or manufacturing large structures on the moon’s surface, which leads to manufacturing defects.”

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

“It is very hard to establish regular machine shops on the moon’s surface to manufacture metal structures as on Earth,” Li continued. “However, it is possible to use spacecraft to ship metal components from the Earth to the moon, such as using the Starship developed by Elon Musk’s SpaceX, then deploy welding technology on the moon to assemble the components into large structures. Welding can enable the establishment of human community on the moon’s surface, reducing logistical burdens and supply needs from Earth.”

“As we try to return to the moon and reach Mars, keeping astronauts safe while achieving the missions is very important. 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.”

— Dr. Edward White, professor and head of the Department of Mechanical Engineering

Li proposed a project that would simulate lunar conditions to troubleshoot the processes of electrical arc, laser and electron beam welding in the lunar environment. He is developing a multi-physics model that includes heat transfer and phase changes with conditions set to mirror the lunar environment conditions. Then, he said he will validate his simulation framework using historical flight experimental data from Skylab, the United States’ first space station.

Li, who directs the Comprehensive Advanced Manufacturing Lab at the Jonsson School, will work with his team to create the environment at UT Dallas while working directly with NASA. He is using a wire-arc validating model, along with a custom-built directed energy deposition (DED) machine used for additive manufacturing of metals.

“I expect to work with Dr. Fredrick Michael from Marshall Space Flight Center (MSFC) at NASA during this project,” Li said. “If there is any opportunity to study welding directly on the Moon’s surface, then I will greatly appreciate that. I have currently established a virtual lunar welding platform to simulate the welding process and welding joint mechanical properties with a multiple physics modeling approach.”

The modeling results will ultimately be validated by both in-space and on-ground experiments to prove their accuracy. Li suggests that the model can be developed further for other in-space environments including Mars and the International Space Station. It could also be used for fused deposition modeling, a type of 3D printing process that can print non-metallic parts under in-space conditions.

Li has served as an assistant professor at UT Dallas since 2019. He completed a PhD in mechanical engineering and a MS in manufacturing engineering from Missouri University of Science and Technology. He also completed an MS in aerospace engineering from Tongji University and a BS in mechanical engineering from the University of Electronic Science and Technology of China. His research interests include in-space manufacturing as well as ultrasonic nanocrystal surface modification and cryogenic DED.