The astronauts, Mike Fincke and Zena Cardman, Japan’s Kimiya Yui and cosmonaut Oleg Platonov, arrived on the ISS on 1 August expecting to complete a standard six and a half month stay. They were due to come home in mid-February.
But last week, a scheduled spacewalk by Fincke and Cardman was called off at the last minute. Hours later, Nasa revealed a crew member had become ill.
“It’s bittersweet,” said Mr Fincke when he handed over the keys to the ISS to Kud-Sverchjov on Monday.
In a social media post, he stressed that all crew members on board were “stable, safe, and well cared for”.
Orbiting Earth at an altitude of 250 miles, the International Space Station (ISS) makes 16 orbits of our planet a day, travelling at a speed of 17,500 miles per hour.
It is run by five space agencies and carries out wide-ranging scientific research about space and the effects on humans, animals and plants of living in microgravity.
