After coolant leak, temperature is rising on Soyuz capsule docked at the ISS

The temperature on the Soyuz capsule docked at the International Space Station has risen but the crew are not in danger, the Russian space agency said Friday as it assesses a leak.

Roscosmos said a number of tests had been conducted following the discovery of a coolant leak on the Soyuz MS-22, and the temperature in the capsule had increased to 30 degrees Celsius (86 degrees Fahrenheit).

On Wednesday, the leak forced the last-minute postponement of a spacewalk by cosmonauts Sergei Prokopiev and Dmitry Petelin.

The spacecraft is currently under evaluation to ensure it can ferry the two Russian cosmonauts and their American colleague Frank Rubio back to Earth.

In a statement, Roscosmos said the "slight change in temperature," was "not critical for the operation of the equipment and the comfort of the crew."

Sergei Krikalev, a former cosmonaut who heads the crewed space flight programme for Roscosmos, said the leak may have been caused by a tiny meteorite striking Soyuz.

Dramatic NASA TV images showed white particles resembling snowflakes streaming out of the rear of the vessel for hours.

According to NASA, "the majority of fluid had leaked out" by Thursday, but the coolant did not pose any danger to the crew members, who were not exposed after the spacewalk was called off.

"Temperatures and humidity within the Soyuz spacecraft (...) are within acceptable limits," the American engineers also said.

Flight controllers, meanwhile, conducted a "successful test" of the spacecraft thrusters on Friday, NASA said, adding that other evaluations remain in progress.

The spacewalk is now expected to take place on December 21.

Space has been a rare avenue of cooperation between Moscow and Washington since the start of Russia's intervention in Ukraine in February and ensuing Western sanctions that shredded ties between the two countries.