The US astronaut returned from the ISS alongside ISS Commander Luca Parmitano from Italy and the European Space Agency (ESA) and Soyuz Commander Alexander Skvortsov from Russia.
Mrs Koch has spent more than 300 days on the ISS, setting the record for the longest spaceflight by a woman astronaut.
According to NASA, the extended mission will pave the way for astronauts to return to the Moon and later Mars.
NASA said: “For Parmitano and Skvortsov, this landing completed a 201-day stay in space, 3,216 orbits of Earth and a journey of 85.2 million miles.
“They launched last July with NASA’s Andrew Morgan.
source: express.co.uk