Last week, a pressure leak occurred on the International Space Station. It was slow and posed no immediate threat to the crew, with the atmosphere leaving the station at a rate such that depressurization of the station would have taken 14 days.

Eventually, US and Russian crew members traced the leak to a 2mm breach in the orbital module of the Soyuz MS-09 vehicle that had flown to the space station in June. The module had carried Russian cosmonaut Sergey Prokopyev, European Space Agency astronaut Alexander Gerst, and NASA's Serena M. Auñón-Chancellor.

The crew on the station was in no danger, and, over the course of several hours, Russian engineers devised a fix that involved epoxy. A preliminary analysis concluded that the vehicle is safe for return to Earth (the orbital module detaches from the small Soyuz capsule before entry into Earth's atmosphere).

The drama might have ended there, as it was initially presumed that the breach had been caused by a tiny bit of orbital debris. However, recent Russian news reports have shown that the problem was, in fact, a manufacturing defect. It remains unclear whether the hole was an accidental error or intentional. There is evidence that a technician saw the drilling mistake and covered the hole with glue, which prevented the problem from being detected during a vacuum test.

“We are able to narrow down the cause to a technological mistake of a technician. We can see the mark where the drill bit slid along the surface of the hull,” Dmitry Rogozin, head of the Russian space agency Roscosmos, told RIA Novosti. (A translation of the Russian articles in this story was provided to Ars by Robinson Mitchell). “We want to find out the full name of who is at fault—and we will.”

Ongoing technical problems

NASA spokesman Dan Huot, based in Houston where the space station program is managed, deferred all comment on the issue to Roscosmos.

The spacecraft was manufactured by Energia, a Russian corporation. A former employee of the company who is now a professor at Moscow State University told another Russian publication that these kinds of incidents have occurred before at Energia.

“I have conducted investigations of all kinds of spacecraft, and after landing, we discovered a hole drilled completely through the hull of a re-entry module," the former Energia employee, Viktor Minenko, said in Gazeta.RU. "But the technician didn't report the defect to anyone but sealed up the hole with epoxy. We found the person, and after a commotion he was terminated,” said Minenko.

In this case, the technician used glue instead of epoxy. As the Soyuz hull is made from an aluminum alloy, it could have been properly repaired on Earth by welding, had the technician reported the mistake.

The Soyuz manufacturing issue represents another significant problem for the Russian space agency's suppliers and its quality control processes. Already, the manufacturer of Proton rockets, Khrunichev, has had several serious problems that have led to launch failures. Rogozin was recently installed as the leader of Roscosmos to try to clean up corruption and address these kinds of issues.

He has his work cut out for him.