The hatch was locked, the crew strapped in, and Space Shuttle Atlantis lifted off at 2:28 P.M. EST in Florida.
Under sunny skies on Launch Pad 39A at NASA's Kennedy Space Center, the crew donned bright orange jumpsuits and rode an elevator to the top of the Shuttle, where close-out crew members strapped them into their seats.
Then the craft tore off through the right blue sky at up to 3,200 miles per hour into outer space, on its mission to deliver parts to the International Space Station. Atlantis weighs 4,525,323 pounds total, including cargo equal to the weight of 2.6 African elephants, and the energy released by the main engine is equal to 13 Hoover Dams.
Atlantis fueling has been underway for several hours, though the process still isn't complete: The tank is now nearly filled with a half-million gallons of super-chilled liquid hydrogen and liquid oxygen and will continue to be topped-off until launch.
Atlantis' STS-129 mission will be an 11-day trek to the orbiting laboratory to deliver two massive platforms packed with spare parts, including pump modules, gyroscopes, a high-pressure gas tank, a latching end for the station's robotic arm, battery equipment, a cargo transportation container, and more. In all, Atlantis will carry about 27,250 pounds worth of supplies.
The shuttle fleet is due to retire in the next year or so and be replaced with new rockets and spacecraft, though NASA's human spaceflight program is under review by the Obama administration.
"This flight is all about spares — basically, we're getting them up there while we still can," said Brian Smith, the lead space station flight director for the mission.
The supply run is vital to pave the way for the future, when NASA plans to retire the space shuttles and their capacity to carry up large hardware to space.
"We're looking for the long-term outfitting of the station, making sure that ISS is ready for the long haul and has the longest life capability possible," said mission commander Charlie Hobaugh in a preflight news conference.
To set up the new spare part carriers, which will be attached to the station's backbone-like truss, the crew plans complex robotic work and three spacewalks, or EVAs (extravehicular activities) in NASA parlance.
"All of the tasks in each one of the EVAs are complex, and we've just been training to keep our focus until we're back in the airlock and safe," said mission specialist Bobby Satcher, one of three crewmembers slated to perform the spacewalks. Satcher and crewmate Leland Melvin are chronicling their spaceflight online using Twitter, with Satcher writing under the name Astro_Bones and Melvin as Astro_Flow.
Atlantis' other STS-129 crewmembers include pilot Barry "Butch" Wilmore and mission specialists Mike Foreman, Randy Bresnik and Melvin. Wilmore, Satcher and Bresnik will be making their first trips to space.
"I'm looking forward to floating around in weightlessness; the ascent itself I hear is just remarkable," Wilmore said.
Space.com contributed to this report.