It's the final countdown for the final touchdown for Discovery, NASA's most traveled space shuttle, which returns to Earth today to cap a 27-year spaceflight career before heading to a museum.

Discovery is on its final descent to Earth for a planned landing at NASA's Kennedy Space Center at 11:57 a.m. EST (1657 GMT). The shuttle and its astronaut crew will touch down on the same runway where, just over two weeks ago, Discovery's six astronauts arrived to begin the orbiter's final journey into space. [Photos of Discovery's Final Mission]

At Kennedy Space Center, crews are ready to support Discovery's arrival, NASA said, including a convoy of nearly 50 vehicles that play various roles in "safing" the orbiter after wheelstop, helping the crew leave the vehicle, and later, towing it back to its processing hangar.

After the landing, the runway will be marked -- showing where Discovery's missions finally ended, NASA said. That moment will cap a prolific career that saw 39 flights in 27 years. After landing, the orbiter will be retired from service, and will eventually be placed on public display in a museum.

"I think the legacy that she leaves behind is quite incredible, " shuttle astronaut Michael Barratt said of Discovery, adding that the spacecraft has been "space-kindly" to its crews, largely due to the team of engineers that maintains the ship. "Even though it's the last time, we really do look forward to bringing her back to her home port and back into those caring hands."

Discovery's last landing day

NASA expected good weather for Discovery's two landing windows in Florida today.

After an early wakeup call this morning, the crew began landing preparations at 6:53 a.m. EST (1153 GMT). The doors of the shuttle's payload bay were closed at 8:12 a.m. EST (1312 GMT).

The astronauts then fired Discovery's orbital maneuvering system engines for about three minutes, in what is called a deorbit burn. This slowed the shuttle down enough for it to begin its hour-long descent.

Discovery is NASA's oldest and most-flown spacecraft, and at the end of its career, will have logged about 148 million miles (238 million kilometers) worth of travel. The STS-133 mission is Discovery's 39th and final flight.

One final voyage

NASA launched Discovery's final mission on Feb. 24, after months of delays owing to problems with the shuttle's external fuel tank. The 13-day mission to the International Space Center delivered supplies, hardware, a new storage module and a humanoid robot assistant to the station and its residents.

NASA is ending its 30-year space shuttle program later this year to focus on exploration beyond low-Earth orbit.

Two remaining shuttle missions are planned – Endeavour's STS-134 flight in April, and the very last STS-135 mission of Atlantis in June. Both missions are headed to the International Space Station to put the final touches on the $100 billion orbiting laboratory.

By coincidence, Endeavour today will roll out to the exact same launch pad used by Discovery to launch its own mission. Endeavour is slated to blast off on its final trip to the space station on April 19. The launch pad move is due to begin at 8 p.m. EST (0100 March 10 GMT) and will be broadcast and webcast live by NASA.

"The legacy for the shuttle fleet and the shuttle program undoubtedly, in my mind, will be the space station," NASA's mission management team leader LeRoy Cain told reporters yesterday. "We could not have assembled this marvelous facility in orbit without the capabilities of the space shuttle."

biccat wrote:Much like the moon landing, I'm sure that the Discovery landing was faked.

Those guys are totally still hanging around out in space, not back here on terra firma.