NASA reverses evacuation alert for astronauts aboard International Space Station

The four Crew-12 mission astronauts — two American astronauts, one astronaut from France, and a Russian cosmonaut — along with another U.S. astronaut were ordered by NASA mission control at 9:04 a.m. ET on Friday to enter their SpaceX‑built Crew Dragon spacecraft docked to the station, NASA spokesperson Bethany Stevens said.

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 examined the rate of leaking air.

NASA’s and Russia’s space agency, 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, an orbital laboratory where astronauts live and work in space.

Chris Cassidy, former NASA chief astronaut who commanded Expedition 63 aboard the ISS in 2020, said that is when staff were first made aware of a leak.

“It’s been troublesome for the last five or six years with engineers on both sides of the ocean figuring out plans to patch it up, but it’s been a pesky one,” Cassidy told CBC News.

Roscosmos said on Friday that its experts had detected two leaks aboard the ISS but that there was no immediate threat to the crew.

NASA livestreams a view of the ISS from an external camera mounted on the station’s Harmony module.

Preparations underway for 2nd leak

The first leak was quickly sealed, and preparations were underway to seal the second one, Roscosmos said, adding that there was no threat to the spacecraft’s systems.

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.

“That’s double the leak rate. So if they were tracking a situation that might give them, say, a month of atmosphere until it trips alarm levels, now all of a sudden that month is 15 days,” Cassidy told CBC News.

The ISS is 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.

What happens when there’s an air leak on the International Space Station? 

A recent air leak aboard the International Space Station prompted astronauts to prepare for a possible evacuation. Former NASA astronaut Chris Cassidy, who was aboard the ISS when a similar leak was first detected in 2020, breaks down emergency procedures and how astronauts respond to safety scares in orbit.

The other crew of one U.S. 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 break into an area where they believe they can access the crack leaking air, the NASA official said. NASA officials disagreed with this method, the NASA official said, prompting mission control in Houston to order safe-haven procedures.

Safe-haven orders are rare

Under the emergency protocol, Cassidy said each crew member is required to shelter in place after returning to the assigned spacecraft that they arrived in, which is the emergency vehicle or designated “lifeboat” for crews should they need to return home.

“It’s a procedure that’s taken seriously because there’s risk to crew and equipment, but more importantly, the crew,” he said.

“They always want to put the crew in a place to be the most safe you can be and that means never putting a hatch between yourself and your escape vehicle.”

Stevens said NASA reversed the safe-haven order and told astronauts they could return the space station once Roscosmos paused its efforts to repair the crack.

“We look forward to working with Roscosmos on a collaborative approach to address the leaks.”

Safe-haven orders are rare on the ISS, 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.

“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 NASA spokesperson said in an earlier post on X.

Legislation is before the U.S. 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 Republican Sen. Ted Cruz and Sen. Maria Cantwell, a Democrat and 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 rivalling China’s growing footprint in space.

Leaders in the U.S. Senate and House of Representatives are working to reach consensus on the proposed legislation.

— Thomson Reuters