When NASA’s Europa Clipper spacecraft sails by Jupiter’s icy moon in the late 2020s, it will be carrying a handful of glass tubes breathed into existence by Mike Souza. The 63-year-old professional glassblower at Princeton University has been creating tricky scientific instruments for nearly 5 decades. His latest project involves a rare and finicky glass that won’t leak helium gas while spinning through the cold, unpredictable void of space—a critical requirement for instruments that will search for life on the frosty moon.
And when a glass production company didn’t have the facility to create instruments for a dark matter experiment, Souza found himself adding the finishing touches on yet another groundbreaking project. This time, he had to shape glass so pure, it would contain almost no traces of radioactive contaminants that could interfere with faint dark matter signals.
Souza chatted with Science about the challenges of blowing glass for scientific experiments, how his creations are being used to study dark matter, and whether he ever puts his skills to more sentimental use. This interview has been edited for clarity and length.
Q: How did you get into glassblowing?
A: It was a form of punishment in our house [laughs]. My dad had five sons, and it was a regular ritual. We’d go down to the glassblowing plant in Evanston, Illinois, and help out the old man. I finished my apprenticeship in 1974 and spent 18 years blowing glass for chemistry, geochemistry, and physics experiments for different universities and scientific glasswork companies.
When I came to Princeton in 1992 as a chemistry glassblower, I began working with a ghastly kind of glass called aluminosilicate, which is used for halogen lamps. It’s a horrific glass to work with. You need a special touch and a lot of practice. Once you get known for working with aluminosilicate, people come to you—that’s how NASA’s Jet Propulsion Laboratory [JPL] found me.
Q: What are you doing for the Europa mission?
A: The glass cylinders I’m making will kind of dangle on the tail end of the spacecraft, like a string of cans on a wedding car. They look like little salt shakers. The cells have to hold helium gas for several years, and since helium is a small molecule, it would work its way through typical glass in 2 to 10 years—and the Europa mission could last much longer than that. Aluminosilicate can hold helium for 20,000 years.
Q: You also handled a specialty glass meant to help Princeton researchers track down dark matter particles, which the team is doing inside a mountain at Italy’s Gran Sasso National Laboratory. What was unique about this glass?
A: Normal glass contains trace elements, and if they decay, they could cause all this radioactive background that would disrupt the dark matter signal. So instead, we had to work with an ultrapure glass. It’s a lot easier to work with than aluminosilicate, but it costs $200,000 for a slab that’s about 5 centimeters thick and 35 centimeters across. It had to be put together in a clean room, and it was nerve-wracking because the lead scientist was right there, watching his glassware that cost more than your house.
Q: JPL didn’t keep a glassblower on staff after their own retired. Is that strange, knowing the number of people in your career is dwindling?
A: It’s really a pressure all universities are facing. Originally, we were hired by chemistry departments to be an in-house manufacturer for stuff, like distillation equipment, that was hard to fix, or was a lot cheaper to have made in-house. Chemistry has shrunk vastly in the amount of glasswork required, but glass has expanded into new sciences, like ion traps for quantum computing research and replicas of patient blood vessels for research. I don’t know what the long-term future will be, but I think glass as a material will be more and more valuable.
Q: Have you ever used your skills to, I don’t know, gift your mom a vase?
A: That’s all I wanted to do when I first started. I’d make a glass rose not for the girlfriend, but for her mother. Nothing gets you faster into their hearts [laughs]. After a while, it becomes kind of like having all the chocolate you want.