Published September 5, 2018
An article on IFL Science about a tiny air leak on a Soyuz capsule docked to the International Space Station that an astronaut plugged with his finger as other astronauts worked on a solution to seal the hole quotes John Crassidis, professor of mechanical and aerospace engineering.
Crassidis said that while a micrometeoroid is a possible culprit for this leak, it could also have been the result of a faulty seal or valve. "Anytime you're connecting something, it's just like a jar where you have a lid on it and it's got a little rubber seal,” he said. "That rubber seal might break down and start leaking."