Hello space station! shouted American Michael Fincke, former colonel in the US Air Force, on the radio when the spacecraft docked with the ISS.
The journey from Kennedy Space Center in Florida with Elon Musk's company Space X took 15 hours, which is unusually fast.
It was an incredibly beautiful sight to see the space station come into our field of vision, said American biologist and astronaut Zena Cardman when she came on board.
The four have had to wait for the journey for over a year but will have to stay for at least half a year. With their arrival, there are now eleven people on the station – but as early as Wednesday, four others will get a ride back to Earth.
The journey to the ISS has been delayed, among other things due to technical problems with the space shuttle system and Boeing's spacecraft Starliner.
The American space agency Nasa plans to save money by letting the astronauts stay longer on the ISS. At the same time, Starliner's next manned flight will be delayed until at least 2026.
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