A major leak from a Russian capsule docked on the International Space Station was most probably caused when a small meteoroid smashed into a radiator, leading to coolant being sprayed into space, a Roscosmos official has said.
Sergei Krikalev, a former cosmonaut who is now director of crewed space flight programs at Russia’s space corporation, said Thursday’s leak from the Soyuz MS-22 could affect the capsule’s overall coolant system but that there was “no threat for the crew” of the space station.
The leak had prompted a pair of cosmonauts to abort a planned spacewalk earlier in the day. It also raises concerns over the capsule’s capability of returning safely to Earth next spring as planned with two cosmonauts and a Nasa astronaut, or whether an emergency replacement vehicle will have to be sent up.
Micrometeoroids, naturally occurring pieces of rock or metal that can be as small as a grain of sand, pose a significant danger to human spaceflight. They hurl around the Earth at about 17,000mph (27,400km/h) – much faster than the speed of a bullet.
Human-made “space junk” can also damage equipment. Last year, Russia blew up one of its own satellites in a missile test that created clouds of zooming shrapnel.
On Thursday, a “visible stream of flakes” prompted Russian flight controllers to abort the spacewalk, a Nasa livestream showed.
“Tonight’s spacewalk has been cancelled because of an observed leak of what is believed to be a cooling substance from the Soyuz MS-22,” the Nasa commentator Rob Navias can be heard saying in a broadcast from Nasa’s Johnson Space Center in Houston, Texas.
“We noticed a visible stream of flakes coming from the aft of the Soyuz near the instrumentation and propulsion module that was indicative of a leak,” Navias added.
The mishap occurred just before two of the Roscosmos cosmonauts, crew commander Sergey Prokopyev and flight engineer Dimitri Petelin, suited up for a planned spacewalk to move a radiator from one module to another on the Russian segment of the ISS.
Earlier, an official for Russia’s mission control operations near Moscow was heard telling the pair in a radio transmission that their spacewalk was being cancelled while engineers worked to determine the nature of the problem.
Nasa also said the ISS crew was not thought to be in any danger from the leak.
Reuters and the Associated Press contributed to this report