Five astronauts took shelter and prepared for a possible evacuation from the International Space Station (ISS) during attempts to fix a worsening air leak.
They were directed by Nasa’s mission control to take refuge in their docked spacecraft on Friday in case they needed to escape quickly as repairs were carried out by a Russian crew on a transfer tunnel, which has suffered from cracking.
Nasa reversed that order roughly two hours later and told the astronauts they could return to the station as the agency and its Russian counterparts Roscosmos examined the rate of leaking air.
Roscosmos said on Friday that its experts had detected two leaks aboard the ISS but that there was no immediate threat to the crew.
The first leak was quickly sealed, and preparations were underway to seal the second one, Roscosmos said on Friday afternoon, adding that there was no threat to the spacecraft’s systems.
Nasa and Roscosmos, the station’s two primary operators, have debated for months over the cause and potential fixes of small air leaks aboard Russia’s Zvezda service module, a key structure of the ISS, a football field-sized orbital laboratory where astronauts live and work in space around 250 miles above the Earth.
The air leaks have been relatively minor in recent months but escalated on Friday from a pound of air per day to two pounds, according to a senior Nasa official who asked not to be named, Reuters reported.
Announcing the precautionary measure, Nasa spokesman Bethany Stevens said in a post on X: “The Zvezda service module transfer tunnel, known as PrK, has suffered from cracks and leaks for some time, and has been mitigated by Roscosmos as much as possible to date.
“The cracks have always been a concern that Nasa watches very closely.
“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.
“Following new leaks, Roscosmos has elected to proceed with a more extensive repair operation on Friday June 5.
“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 under way.
“We continue to work with our Russian counterparts, along with the rest of the international community that supports the space station, to arrive at a more permanent resolution.”
The ISS is currently home to seven astronauts from two missions, including the Crew-12 team — Nasa astronauts Jessica Meir and Jack Hathaway, European Space Agency astronaut Sophie Adenot, and Roscosmos cosmonaut Andrey Fedyaev — who arrived in February.
The other crew of one US astronaut, Christopher Williams, and two cosmonauts, Sergey Kud-Sverchkov and Sergei Mikayev, arrived in November. Kud-Sverchkov and Mikayev, who did not execute evacuation procedures, were planning to use a saw to reach an area where they believe they can access the crack leaking air, the official said.
Nasa officials disagreed with this method, they added, prompting mission control in Houston to order safe-haven procedures.
Ms Stevens later said NASA reversed the safe-haven order and told astronauts they could return to the station once Roscosmos paused its efforts to repair the crack.
Safe-haven orders are rare on the International Space Station, though pieces of space debris that risk colliding with the ISS and smaller changes in air leak rates have triggered the process in recent years. Astronauts have never had to evacuate the ISS in its 27 year history.
Legislation is before the US Congress that would extend the planned life of the space station for two years, until 2032, to give companies more time to develop a replacement.
The bill has the backing of Senator Ted Cruz, a Republican, and Senator Maria Cantwell, a Democrat – the chair and ranking member, respectively, of the Senate Committee on Commerce, Science and Transportation. The legislation is part of the committee’s focus on rivaling China’s growing footprint in space.
Leaders in the US Senate and House of Representatives are working to reach consensus on the proposed legislation.
