NASA finds source of coolant leak from Russia's Soyuz docked at ISS; all astronauts safe

Scientists are continuing to monitor the coolant leakage that occurred on Russia’s Soyuz MS-22 spacecraft docked at the Rassvet module of the International Space Station (ISS). The leakage was first detected at 6:15 am IST on December 15 and the suspected source is the external radiator cooling loop of the Soyuz. Following the detection of the leak, the Roscosmos Mission Control Team in Moscow decided to call off the planned spacewalk which was to be carried out by cosmonauts Sergey Prokopyev (crew commander) and Dimitri Petelin (flight engineer). 

“None of the crew members aboard the space station was in danger, and all conducted normal operations throughout the day”, NASA said in an update. It further revealed that none of the cosmonauts had stepped out of the module for their spacewalk and were not exposed to the coolant. The leakage is said to have occurred around one hour and 40 minutes before the spacewalk and lasted about three hours. 

“Roscosmos is closely monitoring Soyuz spacecraft temperatures, which remain within acceptable limits. NASA and Roscosmos continue to coordinate external imagery and inspection plans to aid in evaluating the external leak location," the update further read. The agencies have also planned an inspection of the exterior of the Soyuz spacecraft using the robotic Canadarm2. 

Installed on the Russian side of the ISS, the Canadarm2 helps in multiple tasks such as installing, removing or replacing experiment payloads, transfer of payloads in and out of the ISS, transporting crew members from one site to another and inspecting the station's exterior using its camera. Notably, this is the same Soyuz spacecraft that was used to transport NASA astronaut Frank Rubio, along with cosmonauts Sergey Prokopyev and Dmitri Petelin to the space station from Kazakhstan on September 21.

"Specialists are working through robotic plans ahead of Monday’s spacewalk to best optimize for upcoming station operations and the Soyuz inspection", NASA said. Meanwhile, the spacewalk remains indefinitely postponed as the teams continue to inspect the anomaly.