Soyuz leak puts a stop to planned ISS spacewalk and work on Nauka module

Королёв, we have a problem …

We don't mean to alarm you, but a Russian Soyuz vehicle docked at the International Space Station (ISS) is leaking a "significant" amount of something, resulting in the cancellation of a spacewalk.

Indeed, it is leaking so much that it is visible to cameras on the ISS. The video embedded in the tweet below appears to show whatever it is that has leaked at the 35 second mark.

Tonight's spacewalk with two cosmonauts has been cancelled as mission controllers evaluate an observed leak on the Soyuz MS-22 crew ship. More... https://t.co/RhlT1kPS7L pic.twitter.com/MyiKMDCGeA

— International Space Station (@Space_Station) December 15, 2022

The video above depicts the Soyuz MS-22 vehicle docked at the Rassvet module.

Commentary on the video describes the leak as "a visible stream of flakes" and added that low pressure in external cooling loops had also been detected.

An initial hypothesis is therefore that the Soyuz is leaking coolant.

Which is not what you really want when your plan is to return the Soyuz to Earth in March 2023, along with three crew. And just to make matters worse, if those three cosmonauts need to get back to Earth in a hurry, MS-22 is how they'll get here. A reminder: when the Sun shines on things in space, they get very hot. Re-entering Earth's atmosphere is also very hot. And lots of heat breaks spacecraft.

The leak is also less than ideal for the entire ISS, as the purpose of the planned spacewalk was to relocate a radiator from the Rassvet module to the Nauka science module.

Rassvet is mostly used for docking and storage. Nauka is a working science lab that was supposed to launch in 2007 but made it to the ISSS in 2021 and had all sorts of unplanned adventures along the way. Then, on its arrival, it fired its thrusters unexpectedly and put the ISS in a spin.

The spacewalk to move the radiator had already been delayed once due to spacesuit issues.

The leak was deemed sufficiently dangerous to end this one, too.

Space agencies are now trying to figure out why and/or what the Soyuz is leaking, so they can put a stop to it and carry on with life as normal on the ISS. Or as normal as it gets on a series of interconnected tin cans, most owned by different nations, orbiting above Earth. ®