The shuttle Endeavour will take its first steps toward space Monday when the ship moves a quarter-mile from its processing hangar to the Vehicle Assembly Building to join a burnt orange fuel tank and twin solid rocket boosters.

Endeavour pilot Gregory H. Johnson sits inside the shuttle during a window inspection in November. Credit: NASA/Cory Huston

Endeavour is scheduled to back out of Orbiter Processing Facility bay No. 2 around 7 a.m. EST (1200 GMT) Monday on a 76-wheel transporter.

The 100-ton space plane has been inside the hangar since landing on its last mission in February 2010.

After being thoroughly inspected and geared up for another mission, the orbiter's payload bay doors were closed in November. Endeavour was precisely weighed and workers measured its center-of-gravity Feb. 14, then technicians mounted the ship atop the transporter Feb. 15. Endeavour's landing gear was retracted in preparation for rollover Feb. 16.

The shuttle's tank and boosters were mated Jan. 19.

Endeavour is being prepared for its 25th and final spaceflight after 19 years of service.

NASA currently plans to pause Endeavour's rollover to give space center employees a last chance to see the black-and-white ship before it goes inside the VAB later Monday morning.

Once the orbiter moves inside the cavernous assembly building, technicians will attach a heavy-lifting crane sling to Endeavour and methodically unbolt the shuttle from the diesel-powered transporter.

The crane will next hoist the 122-foot-long orbiter above the transporter, and the vehicle will drive out from under Endeavour. Then the shuttle will be rotated vertical, pivoted 45 degrees and lifted from the floor of the building's spacious transfer aisle.

Endeavour's external tank joined two solid rocket boosters Jan. 19 in the Vehicle Assembly Building. Credit: NASA/Jack Pfaller

Endeavour should be lowered into the VAB's northeastern high bay early Tuesday morning next to the shuttle's bullet-shaped external tank and solid rocket boosters.

Workers will firmly fasten Endeavour to three attach points on the foam-covered fuel tank, test the fully integrated shuttle and prepare it for rollout to the launch pad.

Endeavour should arrive at launch pad 39A on March 10.

The schedule calls for the shuttle launch team to load cryogenic propellants into Endeavour's fuel tank March 22 in a crucial prelaunch test to check the integrity of the tank structure and foam insulation.

Endeavour's payload of spare parts and scientific gear will get to the launch pad March 24 and be installed in the shuttle's cargo bay March 28.

The STS-134 mission will deliver to the space station the Alpha Magnetic Spectrometer, a highly-sensitive instrument to seek out evidence of enigmatic dark matter and antimatter in the universe.

Endeavour will also haul a cargo pallet to the station with spare parts and a U.S. Air Force experiment.

The shuttle's crew will strap into Endeavour April 1 for a traditional countdown rehearsal.

Endeavour is slated to blast off April 19 at 7:48 p.m. EDT (2348 GMT).