Replacement Soyuz Enroute to ISS

Russia’s Soyuz MS-23 lifted off from the Baikonur Cosmodrome on time this evening enroute to the International Space Station. No one is aboard this flight. It is being sent to replace the damaged Soyuz MS-22 and bring that crew home later this year. Soyuz MS-22 and a Russian cargo spacecraft, Progress MS-21, both sprang leaks in their coolant systems over the past two months. Russian engineers closely examined Progress MS-23 and are confident it will not encounter the same fate.

Liftoff was at 7:24:29 pm Eastern Standard Time, which was February 24, 3:24:29 am Moscow Time or 5:24:29 am at the launch site in Baikonur, Kazakhstan.

The launch was on the same day Moscow Time that marks the one-year anniversary of Russia’s invasion of Ukraine. The leaders of both the United States and Russia have spoken harshly about each other in the past few days, but ISS cooperation continues seemingly unaffected. In fact, two high ranking NASA officials — Associate Administrator for Space Operations Kathy Lueders and ISS Program Manager Joel Montalbano — were in Kazakhstan for the launch.

Soyuz MS-23 was intended to launch two Russians and an American to the ISS as part of the routine changeover of crews every six months. Oleg Kononenko, Nikolai Chub and Loral O’Hara were to replace Sergey Prokopyev, Dmitri Petelin and Frank Rubio who arrived on Soyuz MS-22 in September and were scheduled to return next month.

In December, however, Soyuz MS-22 leaked all its coolant into space, compromising its thermal regulation system and rendering it unsafe to bring the trio home.

Roscosmos and NASA decided to launch Soyuz MS-23 empty to replace Soyuz MS-22 and bring them home later this year. Kononenko, Chub and O’Hara will have to wait to launch on Soyuz MS-24 at that time.

The only occupant of Soyuz MS-23 today is a tiny teddy bear that serves as a zero-g indicator, floating freely once the spacecraft is in orbit. Zero-g indicators are a tradition for both Russian and American crews. The capsule also is carrying 946 pounds of logistics and supplies.

Soyuz MS-23 is using the 34-orbit rendezvous trajectory and will dock at the ISS autonomously on Saturday at 8:01 pm EST. NASA TV coverage begins at 7:15 pm EST.

Once there, Prokopyev, Petelin and Rubio will move their customized seat liners into the new spacecraft. Soyuz MS-22 will undock and return to Earth empty in late March. Russian engineers think the spacecraft will function adequately for a more-or-less routine return to Earth, although what effect the higher heat load could have on computers and other electronics is not clear. The decision not to use it for crew is because they add more heat and humidity.

Engineers concluded the most likely cause of the Soyuz MS-22 leak was a micrometeoroid that hit the radiator and penetrated through to the coolant line. The fact that the Progress MS-21 cargo spacecraft similarly lost its coolant a week and a half ago is raising questions about whether it might have been a common design or manufacturing defect instead, however. Roscosmos concluded it’s not a defect, but another instance of an external impact although not necessarily a micrometeoroid.

The ISS is a partnership among the United States, Russia, Europe, Japan and Canada. Despite the fraught geopolitical climate on Earth and the suspension or termination of just about all other space cooperation with Russia, the ISS relationship seems as strong as ever. Last summer the United States and Russia agreed to resume “seat swaps” where Russians fly on American spaccecraft and Americans fly on Russian spacecraft to ensure that at least one Russian and one American are aboard at any given time. The ISS has a Russian segment and a U.S. segment (that includes modules from Europe and Japan and Canada’s robotic Canadarm2) that are co-dependent. Russian and American crews routinely train in each other’s countries.

Right now, the ISS crew, Expedition 68, is composed of three Americans (Rubio, Nicole Mann and Josh Cassada), three Russians (Prokopyev, Petelin and Anna Kikina), and a Japanese (Koichi Wakata).  Rubio, Prokopyev and Petelin are the Soyuz MS-22 (soom to be MS-23) crew. Mann, Cassada, Wakata and Kikina are Crew-5, coming and going on SpaceX’s Crew Dragon Endurance.

Crew-5 is about to be replaced by Crew-6. That launch was just rescheduled for Monday at 1:45 am EST. Crew-6, on SpaceX’s Crew Dragon Endeavour, has two NASA astronauts, Steve Bowen and Woody Hoburg, one from Roscosmos, Andrey Fedyaev, and one from the United Arab Emirates, Sultan Alneydi, the first UAE astronaut to stay for a long-duration mission (he’s the second UAE astronaut to visit ISS).