Two cosmonauts, NASA astronaut head for Wednesday landing after yearlong mission

The returning Soyuz MS-23/69S crew (clockwise from upper left): NASA astronaut Frank Rubio, flight engineer Dmitri Petelin and commander Sergey Prokopyev. Image: NASA.

Outgoing space station commander Sergei Prokopyev and his two Soyuz crewmates, co-pilot Dmitri Petelin and NASA astronaut Frank Rubio, packed up Tuesday for a fiery plunge back to Earth early Wednesday to close out a yearlong stay in orbit, the longest flight in U.S. space history.

When the trio launched in September 2022, they expected to spend six months aboard the International Space Station, the normal tour of duty for a long-duration crew.

But a coolant leak disabled their Soyuz MS-22/68S ferry ship last December, prompting the Russians to launch a replacement — Soyuz MS-23/69S — last February. That meant Prokopyev, Petelin and Rubio had to stay aloft an additional six months to put the Russian crew-rotation schedule back on track.

If all goes well, they will finally head for home Wednesday, undocking from the space station at 3:54 a.m. EDT and landing on the steppe of Kazakhstan at 7:17 a.m. EDT (5:17 p.m. local time).

During a brief change-of-command ceremony Tuesday, ISS Expedition 69 commander Prokopyev turned the lab over to European Space Agency astronaut Andreas Mogensen, presenting him with a symbolic key to the laboratory.

Speaking to the departing crew members, Mogensen offered congratulations, saying “you have shown resilience, professionalism and grace in the face of unexpected challenges and significant uncertainty.”

“It’s one thing to launch to space, knowing that you’re going to be up here for a year,” he added. “It’s a completely different thing for you and your families to find out towards the end of your six-month mission that you’re going to be spending an additional six months in space. But you took it upon your shoulders, and you excelled.”

He thanked Prokopyev, Petelin and Rubio for their “competence, dedication and hard work” keeping the station shipshape and “setting us up for success” in ISS Expedition 70.

“We hope to leave the space station is as good as condition as we found it,” Mogensen concluded. “No one deserves to go home to their families more than you. We wish you a smooth flight and a soft landing.”

Outgoing space station commander Sergei Prokopyev hands over command of the International Space Station to European Space Agency astronaut Andreas Mogensen during a brief ceremony Tuesday. Prokopyev, Dmitri Petelin and NASA astronaut Frank Rubio (all three wearing black shirts, Rubio at left) plan to return to Earth Wednesday to close out a yearlong stay in space. Image: NASA.

Prokopyev, Petelin and Rubio are being relieved by Soyuz MS-24/70S commander Oleg Kononenko, flight engineer Nicolai Chub and NASA astronaut Loral O’Hara, who arrived at the space station on Sept. 15.

Mogensen flew to the lab last month aboard a SpaceX Crew Dragon spacecraft along with NASA’s Jasmin Moghbeli, Japanese astronaut Satoshi Furukawa and cosmonaut Konstantin Borisov.

Prokopyev, Petelin and Rubio plan to bid their seven station crewmates farewell overnight Tuesday, float into their replacement Soyuz MS-23/69S ferry ship and await undocking from the Russian multi-port Prichal module.

After a fiery plunge back into the atmosphere, the Soyuz crew module, suspended below a large parachute, is expected to settle to a jarring touchdown on the steppe of Kazakhstan near the town of Dzhezkazgan about three-and-a-half hours after undocking. Assuming an on-time touchdown, the crew will have logged 370 days, 21 hours and 22 minutes off planet in a voyage spanning 5,936 orbits and 157 million miles. Prokopyev’s total time in space over two flights will total 568 days.

The late cosmonaut Valery Polyakov holds the world record for the longest single spaceflight, a 438-day stay aboard the Russian Mir space station in 1994-95. Prokopyev, Petelin and Rubio will move to No. 3 on the list, just behind retired cosmonaut Sergei Avdeyev, who logged a 380-day stint aboard Mir in 1998-99.

The longest previous U.S. flight was carried out by Mark Vande Hei, who spent 355 days aboard the International Space Station in 2021-22.