Atlantis has blasted off from the Kennedy Space Centre on the last ever space shuttle mission and despite gloomy weather conditions, the launched took place on time.
"The space shuttle spreads its wings one last time for the start of a sentimental journey into history," a NASA spokesman told the BBC.
Just before taking off, controllers told the crew that no unexpected errors have been encountered, controllers say, before asking them to close their visors.
Moments before the shuttle took off the excitement was clearly palpable as people started to walk towards the viewing positions hoping to get the best place possible.
Before the departure NASA test conductor Roberta Wyrick told the crew: "We salute the entire astronaut force, for your dedication not only to expanding our knowledge of the universe but for the improvements you have contributed to on Earth."
Mission Control also wished the crew luck, telling them "Good luck to you and your crew on your final trip as American icons... Good luck, and have a little fun up there."
Meanwhile, the commander of the mission Chris Ferguson said: "We're completing a chapter of a journey that will never end."
Despite threatening weather conditions, NASA personnel kept their optimism throughout; with the assistant launch director Pete Nickolenko saying before the launch that other than a few minor issues, it had been a good countdown so far. "The vehicle has been performing exceptionally well." The weather around the launch pad is holding and "we are increasing our optimism", he said.
The 12-day mission will now close out the space shuttle program, which began with the launch of Columbia in 1981.
Atlantis will join Discovery and Endeavour in retirement, so NASA can focus on sending astronauts to asteroids and Mars, while private companies will take over the business of getting space station cargo and crews to orbit.