After 186 days spent in space, British astronaut Tim Peake will leave the International Space Station (ISS) to return to Earth on 18 June. Landing in the steppes of Kazakhstan, he will go straight to the European Astronaut Centre in Cologne, Germany, for checkups and research into how humans adapt to living in space.

After launching in December 2015, Peake became the first British European Space Agency (ESA) astronaut to visit the ISS. His mission - known as the "Principia mission" - involved more than thirty scientific experiments for the ESA, a dozen research activities for the other Station partners, and the testing of new technologies in the unique environment of space.

Educating the next generation was also a core element of Principia, with many schools engaging in talks with Peake as well as conducting scientific activities alongside the astronaut's mission - from computer coding, growing plants and maths demonstrations to fitness and nutrition.

Memorable moments

Peake's time in space counted many memorable moments. The most famous one is perhaps his space walk with colleague Tim Kopra to replace a defective component on the station's exterior.

He made history that day, becoming the first ESA British astronaut to walk in space, posting a "selfie" to mark this once-in-a-lifetime occasion.

Peake also ran the London marathon, completing the 42km (26.2mi) on a treadmill, while the event was taking place back on Earth.

Tim Peake
Tim Peake having coffee in space. European Space Agency

Two weeks longer than expected

Peake and two crew mates, Yuri Malenchenko and Tim Kopra, were expected to come back earlier, at the beginning of June 2016. However, the trio that was supposed to replace them was delayed, so the Principia mission ended up lasting nearly two weeks more than estimated at first.

This is because to function at full capacity - and for more scientific experiments to be carried out - six people must be on board the ISS. Peake and his two colleagues therefore stayed longer to help three remaining astronauts on the station, until they could be replaced.

Tim Peake
Tim Peake took this picture during his 4 hour 43 minute spacewalk to replace a failed power regulator and install cablingESA/NASA

"Although I am looking forward to being back on Earth and seeing friends and family again, each day spent living in space is a huge privilege and there is much work to do on the Station", Peake commented.

"This extension will keep the Station at a full crew of six for several days longer, enabling us to accomplish more scientific research. And, of course, I get to enjoy the beautiful view of planet Earth for a little while longer".

The ESA has now announced that the next team - made up of Russian commander Anatoli Ivanishin, Japanese Takuya Onishi and NASA's Kathleen Rubins - would launch on 21 June, now three days after Peake leaves the ISS.

Tim Peake sends New Year message from ISS
British astronaut Tim Peake felt privileged to stay on the ISS Reuters