Unexplained leak cancels Russian ISS spacewalk

The apparent leak, which was visible in NASA's live video feed and appeared as a torrent of snowflake-like particles spraying from the rear section of the Soyuz MS-22 capsule, seemed to be liquid escaping from the spacecraft, possibly coolant, NASA commentator Rob Navias, broadcasting from NASA's Johnson Space Center in Houston, said on the livestream.

The leak began about 8:30 p.m. EST (0130 GMT Thursday). NASA said none of the International Space Station (ISS) crew was thought to be in any danger.

An official for Russia's mission control operations near Moscow was heard telling the two cosmonauts in a radio transmission that their spacewalk was cancelled while engineers worked to determine the nature and origin of the leak.