Air Leak on the International Space Station (ISS) (June 2026)

On June 5, 2026, following a significant increase in air leakage in the PrK transfer tunnel located within the Russian Zvezda service module of the International Space Station (ISS), NASA issued orders to five astronauts to prepare for evacuation.^【1】 The astronauts were instructed to move into the docked SpaceX Dragon capsule named Freedom and remained on standby for approximately two hours in preparation for a possible evacuation.^【2】 The leak is linked to the acute phase of a chronic issue that has persisted on the ISS for approximately six years.

Air leakage on the ISS began to increase on Monday, June 1, 2026. A senior NASA official, speaking on condition of anonymity, stated that the rate of leakage had risen from one pound per day to two pounds per day.^【3】 In response, Roscosmos decided on June 5, 2026, to undertake a more comprehensive repair operation.

NASA’s mission control center in Houston issued orders at 09:04 Eastern Time (13:04 GMT) on the morning of June 5, 2026, to four members of the Crew-12 mission and NASA astronaut Chris Williams to move into the docked Dragon capsule.^【4】 NASA spokesperson Bethany Stevens explained that the decision was based on the principle of “maximum caution.”^【5】 The astronauts were also instructed to don their space suits to be ready for a rapid departure if necessary. During this period, the Dragon capsule remained docked to the station but functioned as a lifeboat ready for immediate undocking.

Russian cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev were not included in the evacuation procedures. The pair planned to use a saw to access the crack causing the leak. According to a senior NASA official who requested anonymity, NASA opposed this method; this disagreement prompted Houston mission control to initiate the safe haven procedure for the five crew members.^【6】

Following Roscosmos’s decision to suspend its repair efforts, NASA spokesperson Bethany Stevens informed the crew to terminate the safe haven procedure and resume planned operations aboard the ISS.^【7】 The astronauts spent approximately two hours inside the Dragon capsule. During the repair attempt, the first of two leak points was sealed using the Germetall-1 sealing material.^【8】 Roscosmos announced that preparations to seal the second leak point were ongoing.

Jessica Meir (Spacecraft Commander): American NASA astronaut and commander of the Dragon spacecraft. She joined the NASA astronaut corps in 2013. This is her second spaceflight.

Jack Hathaway (Spacecraft Pilot): American NASA astronaut and pilot of the Dragon spacecraft. He holds the rank of commander in the U.S. Navy. This is his first spaceflight.

Sophie Adenot (Mission Specialist): French ESA astronaut selected in 2022. She received her engineering education in Toulouse and has served as a helicopter pilot and design engineer.

Andrey Fedyaev (Mission Specialist): Russian Roscosmos cosmonaut. In 2023, he spent 186 days in orbit as a flight engineer on Expedition 69. This is his second long-duration mission.

Chris Williams (Flight Engineer): American NASA astronaut and flight engineer of Expedition 74.

Sergey Kud-Sverchkov (Commander): Russian Roscosmos cosmonaut and commander of Expedition 74. He is one of the cosmonauts leading the repair attempt. The Soyuz MS-28 spacecraft, also docked to the station, has been designated as the emergency escape vehicle.

Sergei Mikaev (Flight Engineer): Russian Roscosmos cosmonaut and flight engineer of Expedition 74. He is one of the cosmonauts leading the repair attempt.

A bill to extend the planned operational life of the ISS by two years until 2032, thereby granting companies additional time to develop a new space station, is under consideration in the U.S. Congress.^【9】 The proposal has received support from Senator Ted Cruz, Republican Chairman of the U.S. Senate Committee on Commerce, Science, and Transportation, and Senator Maria Cantwell, a senior Democrat on the committee. This legislative initiative forms part of the committee’s agenda focused on competing with China’s growing presence in space. Leaders in the U.S. Senate and House of Representatives continue efforts to reach consensus on the proposed legislation.

Stevens noted on a social media platform that the Zvezda service module tunnel had long faced issues with cracks and leaks. She reported that Roscosmos had decided to initiate a comprehensive repair operation following the emergence of new leaks. After Roscosmos suspended its repair activities, Stevens confirmed that the crew aboard the Dragon capsule had been instructed to end the safe haven procedure and resume normal operations on the ISS. Stevens also stated that NASA aims to develop a cooperative approach with Roscosmos to address the leaks.

Roscosmos announced that two leaks had been identified on the ISS but emphasized that there was no immediate threat to the crew. It confirmed that the first leak had been sealed and that preparations for sealing the second were ongoing, with no threat to the spacecraft systems. The Russian news agency Tass, citing Roscosmos, reported that no situation endangering the safety of the crew or the internal systems of the ISS had occurred.