​In preparation for a Russian extravehicular event scheduled for this morning, images provided by cameras located outside the station revealed a leak from the Soyuz MS-22 capsule docked at the International Space Station’s Rassvet port. It is most likely a coolant leak, but this incident could render the Soyuz MS-22 unfit for transporting astronauts aboard the station back to Earth.

Sergei Prokopiev and Dmytro Petelin were preparing to go outside the International Space Station (ISS) this morning for routine extravehicular activity, where they would continue docking operations of the Science Module with the rest of the station, but video cameras outside the station detected a massive leak of what appeared to be coolant from the Soyuz MS-22 capsule docked to the Russian segment of the ISS. The leak lasted for at least 3 hours and was visible during a live broadcast on NASA TV’s YouTube channel.

The European Robotic Arm (ERA) of the Russian Science Module, operated by Anna Kikina, was used to obtain detailed images of where this leak originated. The images arrived on the ground using American communication channels, since the Russian communication system “Luch” is not working.

Extravehicular activity was aborted, and the two did not leave the Search Module (which had already been depressurized to open an external parachute. The source of the leak and its impact on the exterior of the International Space Station, but also on the Soyuz MS-22 capsule, are currently being evaluated.

The coolant could contaminate the suits of the two astronauts, and toxic substances could get inside the station. Also, given the nature of the spill, which is somewhat of a serious ongoing situation, the resources of the command center could not be used for off-ship activities as they had to be directed to the new problem that had arisen.

Worse, the Soyuz MS-22 capsule likely won’t be able to be used to return the astronauts to Earth, and three of them may remain aboard the ISS until a new Soyuz capsule takes over. Fortunately, the Soyuz capsule has the ability to autonomously dock with the ISS without the mandatory presence of a crew on board, but it will be at least a few more weeks before such a capsule is ready for flight.

For safety reasons, the space station has docked vehicles that can pick up the crew and return them to Earth in an emergency, but now the Soyuz MS-22 may not be suitable for this role, and there is a time gap before the arrival of a new capsule carrying the crew cannot be fully evacuated in the event of an emergency.

The Russian space agency said only that “extravehicular activity was interrupted for technical reasons”, without providing further details and without mentioning the incident aboard the Soyuz MS-22 capsule.

Possible causes of this leak could have been malfunctions of the Soyuz capsule subsystem or an impact by a micrometroid or a piece of orbital debris that was too small to be detected.

“Soyuz MS-22” was launched on September 21, 2022, on board were Russians Sergey Prokopyev and Dmytro Petelin, as well as American Francisco Rubio. The return to Earth was to take place at the end of March with the same three astronauts. Currently, three crew capsules (two Dragon capsules and a Soyuz MS-22 capsule) are docked to the ISS, with 7 astronauts on board (3 Americans, 3 Russians and 1 Japanese).

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