Updated at 1:15 p.m. Easterm with Roscosmos statement.
WASHINGTON — NASA instructed astronauts on the International Space Station to briefly shelter in a Dragon spacecraft June 5 as cosmonauts attempted to repair an air leak in a Russian module.
Shortly after 9 a.m. Eastern, NASA Mission Control in Houston instructed the four members of Crew-12, the Crew Dragon mission that has been at the station since February, to shelter in that spacecraft. Joining them was NASA astronaut Chris Williams, who flew to the ISS last November on a Soyuz spacecraft.
The move was prompted by a decision by Roscosmos to have cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev attempt to repair an air leak in a portion of the Zvezda service module known as PrK. That is a vestibule that links a docking port with the rest of the module and has had a long-running, but small, air leak.
That leak had reportedly increased in recent days, leading Roscosmos to pursue a repair effort NASA deemed risky enough to have others on the station shelter in the Crew Dragon.
“Following new leaks, Roscosmos has elected to proceed with a more extensive repair operation on Friday, June 5,” NASA press secretary Bethany Stevens said in a social media post. “Out of an abundance of caution, NASA has directed all four of the agency’s SpaceX Crew-12 members and NASA astronaut Chris Williams to assume an elevated safety posture in the Dragon spacecraft while the repair is underway.”
Less than two hours later, though, controllers told the astronauts they could exit the Dragon after Roscosmos opted not to proceed with the repairs, with the cosmonauts instead taking measurements for later assessment, Stevens said in a follow-up post.
Roscosmos, in its own social media post, said Russian flight controllers detected an air leak with pressurizing PrK earlier on June 5. That led cosmonauts to inspect the vestibule, where they found two potential leak sites. One was coated with a sealant while preparations are underway to seal the other, located on a conical section of the vestibule.
Roscosmos added that the situation poses no threat to the station or its crew, and that air pressure in the station is stable at normal levels.
The air leak in PrK has been monitored for years. Last year, there were signs that repair efforts had stopped the leak, although the root cause of the cracks in the vestibule remained under investigation.
“The current position right now is there are no leaks,” Joel Montalbano, NASA’s acting associate administrator for space operations, said at a March hearing of the House Science Committee. “They’ve put some sealant over it and we’re not leaking.”
However, members of NASA’s ISS Advisory Council noted at an April 29 meeting that NASA and Roscosmos had not settled on a root cause for the leaks and disagreed on the severity of the issue. NASA was also concerned Roscosmos was not adhering to protocols established last August to lower the pressure in PrK when not in use.
The hatch separating PrK from the rest of Zvezda is closed except when the module is in use to access a Progress cargo spacecraft docked there. When the hatch is open, NASA has elected to keep astronauts in the U.S. segment of the station, with a hatch between the U.S. and Russian segments closed.
NASA appeared to show some frustration with the Roscosmos decision to proceed with repairs. “We look forward to working with Roscosmos on a collaborative approach to address the leaks,” Stevens said in the post announcing the repairs were called off.
The station’s astronauts, though, shrugged off the issue as mission controllers worked with them to revise work plans for the day that were interrupted by the incident. “We’ll just clean up our mess and get back to our day,” one astronaut told controllers after completing procedures to exit the Dragon.
