Ricky finds out about space mission
The space shuttle Atlantis has blasted off into space for one its most dangerous missions so far - fixing the Hubble telescope.
Atlantis blasted off from Kennedy Space Centre in Cape Canaveral, Florida just after 7pm UK time.
The giant telescope has been in orbit taking pictures of space for almost 20 years and is badly in need of repair.
The mission's considered really risky as the telescope is a long way from the International Space Station.
That means if something goes wrong, the astronauts can't go to the space station for help.
Shuttle Atlantis blasts into space
But another shuttle will be on standby on Earth so that if the Atlantis is damaged on its flight, the spare shuttle can blast off to rescue the stranded astronauts.
During five long spacewalks, astronauts will repair and replace broken parts and install powerful new cameras.
John Grunsfeld, who's leading the mission, said they'll have to work very hard and very quickly during their spacewalks.
"There's no time to take a breather and look around, it's just going to be work, work, work," he said.
Space expert Doug Millard explains the dangers of the mission
"It's going to be a marathon at a sprint pace for 11 days on orbit."
Hubble has helped teach us about the way the Universe works, showing far-off stars and fantastic sights.
If everything goes to plan, the updated telescope will be 90 times more powerful than it originally was and should last until at least 2014.
Hubble Space Telescope
Launched 600km above the Earth in 1990
15.9m long; 4.2m wide; weighs 11,110kg
Made more than 93,000 trips around our planet
Looked at more than 24,000 things in space