A Russian Soyuz spacecraft has docked at the International Space Station (ISS), ready to take astronauts back to Earth and act as a replacement for another Soyuz that sprang a leak last year. The three affected crew members, NASA’s Frank Rubio and Roscosmos’s Sergey Prokopyev and Dmitri Petelin, will now travel home in this replacement spacecraft later in the year.
The unusual situation of a crewless crew vehicle traveling to the ISS occurred due to a leak that happened in December 2022, when video footage showed liquid spraying out of the MS-22 Soyuz craft that was docked with the ISS. Investigations showed that the leak occurred in the coolant system, which is important for controlling temperatures as the spacecraft travels through Earth’s atmosphere and generates heat. When NASA and Roscosmos looked into the issue, they decided it would be unsafe for astronauts to travel in the MS-22 that had lost its coolant as interior temperatures could get too high for human safety.
The three crewmembers had originally traveled to the ISS in the Soyuz MS-22 in September 2022 without incident. But rather than traveling home in the same vehicle as planned, it was decided to send a replacement Soyuz for them to use instead. It was this replacement Soyuz, named MS-23, which arrived at the space station yesterday, Saturday February 25.
The MS-23 Soyuz arrived at the station at 7:58 p.m. ET (4:58 p.m. ET) after a two-day journey from Earth, where it had launched from the Baikonur Cosmodrome in Kazakhstan. Docking with the station’s Poisk module, it is now available for bringing the crewmembers home. So as not to waste resources, the Soyuz did also carry 940 pounds of supplies to the ISS, according to NASA.
As for the leaky MS-22 Soyuz, that will still be returned to Earth without anyone on board and will be checked for data on how the loss of coolant affects temperatures inside. This kind of information is always useful to know in the case of any future emergencies. The return journey of this Soyuz is scheduled for next month and it will make a parachute-assisted landed in Kazakhstan.