Space shuttle Discovery rolling out for it's final mission.
The space shuttle Discovery rolled out to its launch pad for what is scheduled to be its final mission. Discovery left the Vehicle Assembly Building at 7:23 pm EDT (2323 GMT), arriving at pad 39A about six and a half hours later. Discovery is scheduled to lift off on November 1 on STS-133, the final scheduled mission for the orbiter. On that 11-day mission, the next to last currently scheduled for the shuttle fleet, Discovery will take the Permanent Multipurpose Module packed with supplies and critical spare parts, as well as Robonaut 2 to the International Space Station.
The winged orbiter, the oldest of NASA's space shuttle fleet, emerged from its maintenance hangar for the last time to journey to the nearby Vehicle Assembly Building. Once inside the cavernous 52-story building, Discovery will be attached to the twin solid rocket boosters and external fuel tank that will help launch it to the International Space Station.
Discovery's upcoming STS-133 mission will mark the shuttle's 39th flight to space and NASA's 133rd shuttle flight since the fleet began space launches in 1981. It is NASAs second-to-last space shuttle mission before the fleet retires next year.
The shuttle Endeavours STS-134 mission in late February 2011 is scheduled to be the final flight, though an extra mission on the orbiter Atlantis is under consideration. NASA is retiring its shuttle fleet to make way for a new plan to send astronauts to visit an asteroid by 2025.
Discovery's quarter-mile trip between its maintenance hangar and Vehicle Assembly Building was the 41st rollover in 26 years for Discovery, also known by its orbiter designation OV-103.
Discovery has more rollovers than actual space missions because the shuttle had to repeat the trip on two occasions: once for its maiden flight, STS-41D, in 1984 and again in 1991 before the STS-39 mission. In both cases, the re-rollover was due to Discovery needing repair before it could fly.
Discovery's last journey was made atop the same 36-wheeled transport trailer that has moved Discovery and all of NASAs orbiters before each mission.
The trip between a shuttle hangar and the Vehicle Assembly Building typically takes about a half-hour to complete, but NASA parked Discovery outside its hangar for several hours to allow its employees those who worked on the shuttle to pose with spacecraft for one last set of photos.
Once mated to its boosters and fuel tank an hours-long procedure assisted by a crane that is expected to be completed Friday morning Discovery will embark on a different type of roll.
The completely assembled shuttle stack will ride a massive Apollo-era crawler transporter to the 3.4-mile (5.4-km) trip to Launch Pad 39A. At the pad, Discovery will be readied for its November launch and loaded with its payload.
