The two Russian cosmonauts entered the record book at 4:06:51 on September 20 (Russian time). Mr. Kononenko and Mr. Chub surpassed the previous record of 370 days, 21 hours, 22 minutes set by cosmonauts Sergei Prokopiev, Dmitry Petelin (also Russian) and Francisco Rubio (American) in September 2023.

Russian space agency Roscosmos said in a statement that Mr Kononenko and Mr Chub will continue to stay on the ISS for 374 days until they return to Earth on the Soyuz-MS spacecraft on September 23.

The two astronauts arrived at the ISS on September 15, 2023. This was Mr. Chub's first trip into space and Mr. Kononenko's fifth.

Cosmonaut Kononenko (59 years old) not only set the record for the longest continuous stay on the ISS, but also holds many other records for time spent in space, including a total stay of up to 1,110 days after 5 different missions.

Mr Kononenko also broke a new world record for the longest stay in space by a person, surpassing the record of 878 days and 11 hours set by Russian cosmonaut Gennady Padalka in 2015.

There are currently 15 people on the ISS, including six NASA astronauts and four Roscosmos astronauts. Two of the NASA astronauts, Butch Wilmore and Suni Williams, were originally scheduled to return to Earth in June, but due to a malfunction in the Starliner spacecraft, they were unable to return as planned. They are now scheduled to return to Earth in February 2025.