Operations on the International Space Station may have returned to normal on Friday, but concerns over a persistent air leak in the Russian segment of the station remain unresolved.

NASA spokesperson Bethany Stevens confirmed on Friday that NASA had instructed crew members sheltering in a docked Dragon spacecraft to resume normal operations aboard the International Space Station after Roscosmos paused repair work in the Zvezda service module's transfer tunnel, known as PrK.

Reuters reported that concerns over air leaks in the Russian module prompted NASA to order astronaut Chris Williams and the four-member SpaceX Crew-12 team into the Dragon spacecraft as part of a precautionary safe-haven procedure on Friday. The crew entered the spacecraft wearing spacesuits, per Reuters. Stevens did not specify exactly when the crew was instructed to shelter in place.

The Roscosmos crew was planning to conduct repairs on the transfer tunnel on Friday, but Stevens said that the plan was paused in order to further assess “measurements and data” regarding the new leaks. 

“Given this development, NASA has instructed the crew members inside the Dragon spacecraft to end the safe haven procedures and return to planned operations aboard the International Space Station,” Stevens said. 

What’s life in space without some risks?

Just how big is this crack, exactly?

We’ve known about problems with Zvezda leaks for some time now, as Stevens noted.

“The cracks have always been a concern that NASA watches very closely,” the NASA mouthpiece said in Friday’s X post about the leak. “NASA and Roscosmos have been working to determine the root cause of the cracks, and Roscosmos manages the issue through operational mitigation measures and periodic partial-repair efforts.” 

The Register has been reporting on leaks in the Russian segment of the orbital lab since they were first identified in 2020. Multiple repair efforts over the past few years have failed to stop the leaks entirely, and newly identified cracks suggest the problem is continuing.

Reuters, citing an unnamed NASA official, said that leaks in the Russian section of the station escalated this week from around a pound of air a day to two pounds. A source The Register spoke with said that the latest discoveries were the longest cracks in the module they’d seen, though we’re still not clear on how large the cracks actually are. 

Russian news wire Interfax reported that cosmonauts identified two potential air leaks in the transfer chamber, one of which was sealed on Friday with a layer of Germetall-1 two-component sealant, but the second hasn’t been addressed yet. 

“Efforts are underway to prepare it for hermetic sealing,” Roscosmos said in a statement. 

We’ll update this story if we hear anything new from NASA, including whether the continued leaks, with cause unknown, could lead to an early retirement for the station. ®