In a spectacular and at times nail-biting afternoon launch, the space shuttle Discovery blasted off on one final mission today (Feb. 24) to cap off its prolific 27 years of spaceflight.

Amid clear skies and warm temperatures, Discovery lifted off at 4:53 p.m. EST (2153 GMT) today from Launch Pad 39A here at NASA’s Kennedy Space Center.

The launch came as a relief after a last-minute glitch arose in a range-safety computer, threatening to prevent the liftoff. NASA cannot launch a shuttle unless the air space over Cape Canaveral is cleared by range safety officials. The issue was resolved within minutes of the launch, allowing Discovery to fly after all.

The successful launch marks the beginning of Discovery’s STS-133 mission – its 39th and final flight to the International Space Station before it is retired from service. The liftoff came after months of delay over problems with the shuttle’s fuel tank. NASA also had to tackle an emergency repair today to fix a nicked heat shield tile near Discovery’s crew hatch.

The 11-day mission will deliver important supplies and critical hardware to the space station, including a much-needed storage module that will be attached to the Earth-facing side of the American Unity node. Discovery is also carrying what will become the space station’s first permanent robotic resident — the humanoid Robonaut 2.

Discovery will dock at the space station on Saturday (Feb. 26).

“STS-133 crew and Discovery, welcome to space! We just doubled the number of extraterrestrial humans!” wrote Italian astronaut Paolo Nespoli on Twitter, from his perch on the International Space Station. Nespoli is one of six long-term crewmembers living at the orbital outpost right now.

Discovery is NASA’s oldest and most-flown space shuttle. It was first launched in August 1984, and has since traveled more than 142 million miles and carried 246 crewmembers into space, NASA officials said.

CREW ENTERING SHUTTLE

The veteran shuttle’s last crew is made up of commander Steve Lindsey, pilot Eric Boe, and mission specialists Michael Barratt, Alvin Drew, Steve Bowen and Nicole Stott.

“Thanks for all your kind words for me & the whole STS133 crew. Will try to tweet from space. Go Discovery!” Stott wrote on Twitter prior to launch.

CREW HEADS TO THE PAD

Mission specialist Bowen was a last-minute substitute for astronaut Tim Kopra, who was injured in a bicycle accident in January. In addition to the standard duties as a mission specialist, Bowen will also take Kopra’s place on two planned spacewalks to perform routine station maintenance.

(Source: NASA.gov / Space.com)