By Christina Horsten

Washington, D.C. (USA) - Two US astronauts had to waitmore than nine months on the International Space Station (ISS) due to a technical malfunction - now their return journey to Earth has begun.

Suni Williams (59) and Barry Wilmore (62), who were originally only supposed to stay in space for a few days, left the ISS on board a Crew Dragon space capsule, as live footage from the US space agency Nasa showed.

They were joined by their US colleague Nick Hague (49) and Russian cosmonaut Alexander Gorbunov (34), who both arrived on the ISS in September. The capsule of "Crew 9" is due to land in the sea off the coast of the US state of Florida at around 11 p.m. German time.

Williams and Wilmore arrived at the ISS at the beginning of June and were only supposed to stay there for around a week. However, due to technical problems with their "Starliner" spacecraft, NASA decided for safety reasons to let the spacecraft, which was developed by the US company Boeing, fly back to Earth empty.

In September, only two instead of the originally planned four space travelers, Hague and Gorbunov, flew to the ISS in a 'Crew Dragon' from tech billionaire Elon Musk 's (53) space company SpaceX - leaving two places free for Williams and Wilmore.

The 59-year-old Williams and her 62-year-old colleague Wilmore had been in space several times before and are considered experienced astronauts. Hague and Gorbunov had planned from the outset to stay on the space station for six months.

At the weekend, the four-member "Crew 10" arrived at the outpost of humanity to replace "Crew 9" on board the ISS.

The US astronauts Anne McClain (45) and Nichole Ayers (36), the Japanese astronaut Takuya Onishi (49) and the Russian cosmonaut Kirill Peskov (34) are to remain in space until the fall. They were greeted with warm hugs.

US astronaut Don Pettit (69) and the two Russian cosmonauts Alexei Ovchinin (53) and Ivan Wagner (39) will also remain on board the ISS as planned. They arrived there in September.