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The initial step, dubbed “Go for Stack,� will be installation of the bottom portion of the solid rocket boosters known as aft skirts upon which will be stacked the booster segments, the external tank and then Endeavour.

The 20-story tall display will show the shuttle as it would appear waiting on a launch pad.

Endeavour was built as a replacement for the destroyed shuttle Challenger and flew 25 missions between 1992 and 2011.

When NASA’s shuttles were retired, Endeavour was flown to California atop NASA’s special Boeing 747 shuttle carrier in 2012, drawing crowds as it flew over locations in the state associated with the space program.

After landing at Los Angeles International Airport, the shuttle was placed on a special trailer and then created a sensation as it was inched through tight city streets to the California Science Center over several days.

A for the Air and Space Center was held last year on the 11th anniversary of Endeavour's final return from space.

The center said in a statement that stacking the components of the shuttle system is a complex process that has never been undertaken outside a NASA facility.

Dec. 31 will be the last chance to see Endeavour as it has been displayed horizontally in the landing position for years since arrival at the center.

The shuttle will be moved across Exposition Park and lifted by a crane to be intricately mated to the external tank. Construction of the Air and Space Center will be completed around the full shuttle stack.

The center's foundation has raised $320 million of the $400 million goal for the project.

Exposition Park is between the University of Southern California and Los Angeles Memorial Coliseum.