A Russian 'Soyuz' spacecraft, with three astronauts on board, has docked at the International Space Station (ISS).
After a two-day journey, one American astronaut and two Russian cosmonauts have arrived and they'll work on board the station until September.
The ISS is a floating research lab in space and orbits about 240 miles away from Earth.
As well as a safe arrival there was another reason to celebrate - it was the American astronaut Joseph Acaba's birthday!
Watch the clip to see the spaceship and astronauts arriving at the space station.