September 23, 2024

— Two Russian cosmonauts have returned to Earth after a record-long stay aboard the International Space Station (ISS), but for one of them, the past 374 days has amounted to barely a third of his total time spent in space.

Oleg Kononenko and Nikolai Chub, along with NASA astronaut Tracy Caldwell Dyson, landed on Russia's Soyuz MS-25 spacecraft on Monday (Sept. 23). The 7:59 a.m. EDT (1159 GMT or 4:59 p.m. local time) touchdown on the steppe of Kazakhstan concluded Kononenko and Chub's more than yearlong mission and a 184-day stay on the ISS for Dyson.

Together with the time she logged on two previous spaceflights, Dyson is now just one day short of tying Chub's single mission tally of 374 days (373 days, 20 hours and 13 minutes) in Earth orbit.

For Kononenko, though, the landing marked the end of his 1,111th day (1110 days, 14 hours and 56 minutes) in space, accumulated over five missions. Kononenko is the first person in history to exceed 1,000 days off Earth. The previous record was the 878 days logged by cosmonaut Gennady Padalka over the course of five missions, as set in September 2015.

Soyuz MS-25 landing highlights. Click to enlarge video in new pop-up window. (NASA)

"Oleg, we'll miss your hundreds of stories around the dinner table, but I guess that is what you get for having over a thousand days in space," said NASA astronaut Sunita Williams, who took over command of the station from Kononenko during a handover ceremony on Sunday.

At present, there are no active space travelers who are within a year of matching Kononenko's record. Former NASA astronaut Peggy Whitson, who is now leading short-duration commercial missions for Axiom Space, is closest with 675 days to date. She is expected to add between two and three weeks to that count when she commands the Axiom-4 (Ax-4) mission next year.

Kononenko and Chub's yearlong flight began with their arrival at the ISS on Soyuz MS-24 with NASA astronaut Loral O'Hara in September 2023. Rather than return to Earth with their launch-mate, the two remained on the space station to allow for a short-duration visit by spaceflight participant Marina Vasilevskaya of Belarus and Russian cosmonaut Oleg Novitskiy.

Vasilevskaya and Novitskiy rode with Dyson to the ISS in March and then returned to Earth with O'Hara after just a 12-day stay in April.

Kononenko, Chub and Dyson's departure from the station marked the official end of the station's 71st expedition and began Expedition 72. Soyuz MS-25 undocked from the orbiting lab's Prichal node at 4:36 a.m. EDT (0836 GMT), about three and a half hours before it made a parachute- and braking thruster-assisted touchdown southeast of the Kazakh town of Dzhezkazgan.

"Thanks to all my crewmates for your friendship. It has been a great time and pleasure to work and spend time together here as a big family on board the International Space Station," said Kononenko. "Right now I am leaving my second home."

Remaining on the station to begin Expedition 72 are NASA astronauts Williams, Butch Wilmore, Matthew Dominick, Michael Barratt, Jeanette Epps and Don Pettit, as well as cosmonauts Aleksey Ovchinin, Ivan Vagner and Alexander Grebenkin. NASA astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov are scheduled to arrive at the station on SpaceX's Dragon "Freedom" on Thursday (Sept. 26), followed by Dominick, Barratt, Epps and Grebenkin leaving on Dragon "Endeavour" about a week later.

Kononenko, 60, and Chub, 40, are the seventh and eighth people in history to log 365 days or more on a single mission. Their 374 days together is the longest stay to date on the ISS, surpassing the 370 days and 21 hours logged by cosmonauts Sergei Prokopyev and Dmitri Petelin together with NASA astronaut Frank Rubio in September 2023.

Kononenko became the 482nd person in space and 473rd to enter orbit on his first launch in 2008, according to the Association of Space Explorers' Registry of Space Travelers. He has flown on five Soyuz and 11 ISS expeditions crews. He performed seven spacewalks, including two with Chub during this latest flight.

Chub became the 666th person to fly into space and 605th to orbit on this, his first mission.

Dyson, 55, flew as a mission specialist on the space shuttle Endeavour in 2007 and as a flight engineer on Soyuz TMA-18/Expedition 23 in 2010. She is the 467th person in space, 458th in orbit and 47th woman to spend time off the planet.

With the MS-25 crewmates safely back on Earth, the three were next to fly by helicopter to the recovery staging city of Karaganda, Kazakhstan. From there, Dyson will board a NASA plane and return to Houston, while Kononenko and Chub will depart for their training base in Star City, Russia, outside of Moscow.

Soyuz MS-25 was Russia's 71st Soyuz to launch for the International Space Station since 2000 and 154th to fly since 1967. During its 184 days in space, it traveled 78 million miles (125.5 million km) while completing 2,944 Earth orbits.