Atlantis launches from Cape Kennedy
The 135th and final space shuttle mission has lifted off from Cape Canaveral in Florida, reports the BBC.
Space shuttle Atlantis was launched into history at 1129 local time (1529 GMT; 1629 BST) on Friday.
The 12-day mission will ferry 3.5 tonnes of supplies to the International Space Station.
Upon its return, the 30-year space shuttle programme will come to a close, with Atlantis and the other two shuttles retired to museums.
Just seconds before launch, NASA had to halt the countdown to check that a piece of launch pad equipment called the gaseous vent arm had been moved out of the shuttle's way.
But after controllers were satisfied there were no problems, the signal was given to proceed with lift-off.
For much of the week, a launch had been thought highly unlikely.
The weather on Thursday had thrown torrential rain at the orbiter, and forecasters had been talking grimly of similar conditions developing on Friday.
But the promised showers never materialised and controllers in the "firing room" gave the "go" for the ascent after a positive poll from their ground teams.
The call prompted a huge cheer from the thousands of guests inside the Kennedy Space Centre and a rush to grab the best viewing positions.
Many lined the tops of buildings around KSC; others went down by the famous countdown clock on the lawn in front of the press complex.
They, and hundreds of thousands more people outside the centre, did not see Atlantis for long.
A few seconds after thundering off the pad, she disappeared through a bank of cloud for the chase out over the Atlantic and a rendezvous with the International Space Station (ISS) on Sunday.
The ship and her crew of four - Chris Ferguson, Doug Hurley, Sandy Magnus and Rex Walheim - will spend seven days at the orbiting platform.
Mission goals include the delivery of a huge load of food for the ISS residents and a robotics facility that will test strategies for re-fuelling satellites high above the planet.
There has been much talk here in the past few days about the end of an era and the consequences it will have for the Kennedy workforce, many of whom will lose their jobs.
NASA has attempted to shift the debate to what comes next and the strategy it has adopted to replace the expensive orbiter programme.
The agency believes a more affordable approach to getting astronauts to the ISS can be achieved by contracting out their transport to private companies.
One of those prospective commercial concerns, Boeing, has been displaying a model at KSC of a capsule it says could lift up to seven individuals to the station.
Another, the Sierra Nevada Corporation, signed an agreement with NASA on Thursday to use Kennedy's facilities.
SNC is producing a mini-shuttle it calls the Dream Chaser, which, again, could carry up to seven astronauts into low-Earth orbit.