Former Astronaut Leads Development of Virtual Digital Twins for High-Performance, Custom-Fit Extravehicular Activity (EVA) Spacesuits
By Anne Wainscott-Sargent, AIAA Communications Team
ORLANDO, Fla. – During her astronaut career flying on five Space Shuttle missions, Professor Bonnie J. Dunbar recalls the challenges of ill-fitting EVA “modular, mix-and-match” spacesuits. Ironically, it was during training in Russia as a crewmember traveling to the Russian Space Station Mir, that she experienced the advantages of a customized, pressurized spacesuit.
Speaking on day three of the 2025 AIAA SciTech Forum in Orlando about spacesuit advances, Dunbar shared how she was so comfortable in the customized Sokol Pressure suit, that she napped for four hours while testing the suit/SOYUZ seat combination in a vacuum chamber at Star City, home to the Yuri Gagarin Cosmonaut Training Center in Moscow.
Challenges with Fit and Customization
“Poorly fitting pressure suits that reduce mobility and have a high energy cost impact both mission success and safety. But customization had not been used since the Apollo program, where each crewmember had three custom suits: one for flight, one for back-up, and one for training,” she explained.
During the Shuttle program era, NASA went to a modular design for suits with five “chest sizes” and mix-and-match set of arms and legs, said Dunbar, recalling that the result was “suits that didn’t fit everyone as well as they should.” Some astronauts experienced injuries during missions such as shoulder issues that required surgery when they returned home. These problems are currently captured as risks by both the NASA engineering and human research organizations.
She asked: “How can we use new modern digital engineering tools to revisit customization to maximize performance, and reduce injury, in a cost-effective and schedule-sensitive manner?”
Today, as director of the Aerospace Human Systems Laboratory in the Aerospace Engineering Department at Texas A&M University, Dunbar is bringing her unique experience to bear, spearheading research that could inform what future astronauts will wear on missions to Mars and teaching students about “Human Systems Integration.”
NASA Funds Digital Thread Research
NASA was so interested in her digital concept that they gave her a Phase 1 NIAC (NASA Innovative Advanced Concepts) grant for the development of an EVA suit digital thread. Using tools such as 3D human scanners and finite element (FEA) technology to model the pressurized fabric layers of the suits, she hopes to create a digital system where custom spacesuits, optimized for joint mobility and energy expenditure before manufacture, will become a reality. This step in the digital thread is called “the virtual twin.”
“Spacesuits are not a fashion statement,” said the former NASA astronaut. Instead, think of it as “a human-shaped spacecraft.”
In addition to being pressurized, the 14-layer EVA suit generally includes a communication system, life support (oxygen for breathing and CO2 removal), thermal management, displays and controls, battery power, computers, advanced materials, radiation mitigation, micro-meteoroid protection, and sensors. When pressurized, fabrics become rigid (think of a balloon). If the joints are not properly designed or positioned with respect to the astronauts’ joints, an astronaut can lose as much as 50% of their effective strength, experience reduced mobility, and expend more energy in required EVA exploration tasks.
Dunbar’s research could also benefit current efforts by Axiom Space, which is designing the new EVA suit for the lunar Artemis mission. Axiom unveiled the AxEMU (Axiom Extravehicular Mobility Unit) prototype in spring 2023. Featuring new tech, safety features, and enhanced comfort and mobility, the AxEMU includes innovative life-support systems, pressure garments, and avionics. It’s designed to accommodate 1%-99% of the U.S. population.
Having a future tool to virtually evaluate the suit for that large range of anthropometric sizes before manufacturing could mitigate future performance challenges. SpaceX is currently designing customized suits, but could also benefit from virtual performance evaluations (virtual twin) prior to manufacture.
The Gold Standard for Spacesuit Design
Dunbar considers the dual goals of maximizing mobility and reducing energy expenditure “the gold rings” for spacesuit design.
“I wanted to take it [spacesuit design] from the Pillsbury Doughboy stage to ‘The Martian’ stage,” said Dunbar, referring to the advancements in suit design from the 1970s and 1980s to what was shown in the futuristic Mars adventure film starring Matt Damon.
Using human digital scanners such as 3dMD and VITUS in her lab that can deliver millimeter accuracy, she took the approach of aircraft designers: building a virtual twin.
“The goal is to integrate the virtual suit with the virtual person, and to model the torque and forces required to deform a pressurized joint using FEA tools,” explained Dunbar. “By iterating sleeve dimensions, joint designs, material properties, and delta pressures through sensitivity testing, we can identify critical factors for performance.”
Dunbar has advised one Ph.D. student and three M.S. students on this topic, all with published papers, both for modelling and breadboard testing. She plans to present an overview of the current research later this year.
Raising the TRL of the Virtual Twins for Suit Design
“We’re continuing our work,” she said, estimating that her lab’s efforts to build virtual twins for suit design is currently at Technology Readiness Level (TRL) 3-4. To raise the TRL will require industry partners,” Dunbar said.
The Texas A&M researcher’s vision for tomorrow’s astronauts is powerful yet simple: “I step into the scanner. A few days later, I have a suit that comfortably fits and is mobile, and because it may be designed for Mars, it will be reliable, relatively simple, and easily repairable.”
While it’s still early days, Dunbar is hopeful that her lab is on the right path to create a future platform that delivers on that vision.
To learn more about Bonnie Dunbar’s innovative work and the process envisioned to support future spacesuits, check out a 2023 NASA/NIAC book, Made-to-Order Spacesuits featuring NASA Inventor Bonnie Dunbar.