In early April, astronauts Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen were thrust into the international spotlight as they piloted Artemis II, the first crewed flight beyond low Earth orbit since 1972. We all learned their names.

But for missions like that to succeed, it takes the work of untold personnel behind the scenes: people like engineers, scientists, and even statisticians.

Last summer, Virginia Tech statisticians Geoff Vining M.S. ’86, Ph.D. ’88 and Anne Driscoll M.S. ’07, Ph.D. ’11 were honored as part of the NASA Engineering and Safety Center stress rupture assessment team, which examined composite overwrapped pressure vessels (COPVs) on the International Space Station. COPVs are ubiquitous within NASA, found on space flight systems everywhere to store propellants, life-support elements, and other commodities.

The team, which was presented an agency-wide NASA Group Achievement Award for its more than decade-long study of COPV reliability, included both government and non-government personnel, including two additional NASA employees with ties to the Virginia Tech Department of Statistics: Pete Parker M.S. ’03, Ph.D. ’05 and Sara Wilson Ph.D. ’09.

Man and woman hold award in front of NASA backdrop.
Professor Emeritus Geoff Vining M.S. '86, Ph.D. '88 (at left) and Collegiate Professor Anne Driscoll M.S. '07., Ph.D. '11,, both of the Department of Statistics, receive the NASA Group Achievement Award. They were part of the NASA Engineering and Safety Center stress rupture assessment team that studied the reliability of composite overwrapped pressure vessels. Photo courtesy of NASA.

About the project

COPVs are lightweight vessels that are designed to store gasses under pressure, typically consisting of a metal or plastic liner surrounded by a composite overwrap made from a matrix of fiber strands.

Because failure of these components can be catastrophic to crew and the mission — “If it ruptures, it's the equivalent of an explosion with dynamite,” said Parker — the NASA Engineering and Safety Center has made a significant investment in understanding COPVs, commissioning more than 30 COPV-related assessments in the past decade and a half.

The study completed by the stress rupture assessment team focused on acquiring strand stress-rupture data to develop a global stress rupture model as well as supplementing small-scale COPV tests completed by the International Space Station and obtaining sufficient data to provide an understanding of stress rupture in carbon fiber strands.

“When we initially began this, people didn't know what the failure mechanism was,” said Vining, professor emeritus in the Department of Statistics. “There are a lot of things that are published in the literature, which are purely academic and cannot be evaluated through formal experimentation.”

Because it is difficult to replicate the conditions of a COPV in space, the team worked off a theory that one of two things would occur: if the vessel was able to withstand a stress test, it would never fail, or the stress test would cause the vessel to fail faster.

In the end, the team determined that if a vessel doesn’t fail during an initial stress test, “it will last literally forever,” said Vining. “That makes NASA’s life much easier.”

The study results allowed the NASA Engineering and Safety Center to provide recommendations for future situations where stress rupture reliability estimation is required.

Line of COPVs in machine that will conduct stress rupture testing.
Multiple composite overwrapped pressure vessels (COPV) undergo stress rupture testing. Photo courtesy of NASA.
Damage caused by the explosion of a composite overwrapped pressure vessel
Results of a failed COPV test. Because COPVs contain high pressure gases, the vessels can have tremendous explosive energy. Photo courtesy of NASA.

Making the connection

Virginia Tech statisticians became involved in the COPV studies largely through Parker, who discovered the value of industrial statistics while working as a mechanical engineer at NASA.

Utilizing statistical concepts, Parker — who also had a background in applied physics and computer science — developed a system that reduced a monthlong procedure to just three days.

Recognizing the broad value of statistics to his work, Parker enrolled in NASA’s graduate study program and moved to Blacksburg for two years to pursue his advanced degrees. He completed his master’s degree in the first year. It took a third year of commuting between the Langley Research Center and Blacksburg to finish his Ph.D.

The effort paid off, as his training opened the door for collaborations between NASA and statistics departments at numerous universities including Virginia Tech.

Man in astronaut flight suit hands award to man in suit in front of NASA backdrop.
Pete Parker M.S. '03, Ph.D. '05 (at left) receives the NASA Silver Snoopy Award from astronaut Victor Glover in 2024. The Silver Snoopy is awarded to NASA employees and contractors across the agency for outstanding achievements related to astronaut safety or mission success, and is given to less than 1 percent of the NASA workforce annually. Sara Wilson Ph.D. '09 received the Silver Snoopy in 2025. Photo courtesy of NASA.

Virginia Tech collaborators

Vining, who started receiving funding from a National Institute of Aerospace grant in 2007 for rapid prototyping studies, began his work on COPV reliability analysis in 2009. Among the team members on that project were then-graduate students Laura Freeman and Matt Williams. Freeman, who currently serves as the deputy director of the Virginia Tech National Security Institute, even came up with the experiment — affectionately dubbed “Laura’s Plan” — which was later executed by the stress rupture assessment team.

Meanwhile, Driscoll, a collegiate professor who currently serves as director of undergraduate studies in the Department of Statistics, was brought onto the COPV project in 2014. After getting her master’s degree and Ph.D., she remained in Blacksburg as a visiting professor and wanted to enhance her professional profile. Vining presented her with the opportunity to join the NASA Engineering and Safety Center team. Intimidated by the project, Driscoll reluctantly agreed – and was glad that she did.

As a young statistician, Driscoll was able to learn from her more experienced colleagues, strengthened her knowledge in areas like coding and reliability statistics, while also getting an education about team dynamics.

“Honestly, it's probably the best thing that I've done as a faculty member at Virginia Tech,” she said.

Why statistics matter

The COPV study was never meant to last for more than a decade – as Vining said, most NASA Engineering and Safety Center projects are completed in less than a year. But the importance of this project, as well as its complexity and necessity for sound statistical analysis, kept the study going for much longer. Reaching a conclusion required getting the right people on the team at the right time.

“As a statistician, I feel we need to have a seat at the table,” said Driscoll. “In these collaborative teams, we have real impact that leads to good science.”

The work done by Virginia Tech statisticians and their colleagues in studying COPVs contributed to the development of new technical guidelines for demonstrating COPV damage tolerance, released by the NASA Engineering and Safety Center earlier this year.

“The best part of being a statistician is that we help people make decisions in the presence of uncertainty,” said Parker. “Every decision comes with some lack of data, and there’s lots of ways to make those decisions – you can have a gut feeling, you can flip a coin. But statistics provides a rigorous, methodological way to support those decisions, and to have it in a data-driven defensible way.”

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