Space Shuttle Discovery Blasts Off on Final Flight

Space shuttle Discovery lifts off from Pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., Thursday, Feb. 24, 2011. (AP Photo/Chris O'Meara)

CAPE CANAVERAL, Florida – NASA's most traveled space shuttle blasted off on its final voyage, following nearly three decades of service.

During the launch, Discovery's engines carried it aloft on nearly 1 million pounds of thrust, leading to forces on the astronauts within the vehicle three times that of Earth's gravity, NASA said. Discovery thundered to speeds of about 18,000 miles per hour within 8 1/2 minutes on its journey, en route to a meetup with the International Space Station Saturday.

"We're already 66 miles up!" the robot astronaut Robonaut 2 tweeted, mere minutes after the rocket launch.

The shuttle reached orbit within 15 minutes of launch. "Good to be here," Discovery commander Steve Lindsey radioed soon after the three main engines shut off and the external fuel tank was jettisoned.

Discovery is the oldest of NASA's three surviving space shuttles and the first to be decommissioned this year. Two missions remain, first by Atlantis and then Endeavour, to end the 30-year program. Launch director Mike Leinbach anticipated it would be "tough" to see Discovery take off for the 39th and final time, and even harder when it returns March 7.

"It's a very, very personal thing that we love to do," Leinbach explained. "It's a lot more than just our livelihood. It gets in our soul."

Emotions ran high as Discovery rocketed off its seaside pad into a late afternoon clear blue sky, and arced out over the Atlantic on its farewell flight. There were a tense few minutes before liftoff when an Air Force computer problem popped up. The issue was resolved and Discovery took off about three minutes late, with just a few seconds left.

"The venerable veteran of America's human spaceflight fleet," as the launch commentator called it earlier in the day, will carry the Leonardo Permanent Multipurpose Module, or PMM, to the International Space Station. The PMM has been loaded with supplies, experiments, equipment and the humanoid robot assistant Robonaut 2 -- the first robot of its kind to fly into and work in space.

NASA pumped hundreds of thousands of gallons of fuel into Discovery at midmorning. This time, no hydrogen gas seeped out during fueling and no cracks developed in the external fuel tank. Both problems cropped up during the initial countdown in November, leading to months of repairs. Cracks in the midsection of the tank, which holds instruments but no fuel, could have been dangerous.

This was the 39th flight for Discovery, set to retire this year and eventually make its way to a museum. It has logged 143 million miles (230 million kilometers) since its first flight in 1984.

Discovery will spend 11 days in orbit -- on top of the 352 days it's already spent circling the planet -- and will rack up another 4.5 million miles (7.2 million kilometers).

Its list of achievements include delivering the Hubble Space Telescope to orbit, carrying the first Russian cosmonaut to launch on a U.S. spaceship, returning Mercury astronaut John Glenn to orbit, and bringing shuttle flights back to life after the Challenger and Columbia accidents.

"She's been an amazing machine," Leinbach said Wednesday. "She's done everything we've asked of her."

The Associated Press contributed to this report.