The Space Shuttle Discovery has blasted off from America's Kennedy Space Center on a 14-day mission.
SPACE SHUTTLE DISCOVERY
See the shuttle blasting into space
The seven astronauts on board will be carrying on with building work on the International Space Station (ISS).
They'll be installing something called the Harmony node, which will provide a passageway to a new lab that's due to be fitted to the ISS in December.
When the mission is complete it means astronauts will have more space to live and work at the station.
The crew will carry out five space walks during their mission as they've got some other odd jobs to do while they're out there as well.
And some of the astronauts will be staying in space for longer than two weeks so others who are already out there can come back to Earth.