The moves, which took only a few hours to complete, were relatively simple and straightforward.

The two aft skirts were mounted atop a seismic-isolated 1,800-ton slab of concrete, protecting the future display from being toppled by an earthquake. Two workers on a red ladder toil inside a white dome-shaped structure Related: Where are NASA's space shuttles now? 'This is the first step in the six-month process of creating the world's only authentic ready-to-launch space shuttle stack in the Samuel Ocean Air and Space Center.' 'Today, with the installation of the two aft skirts, we commence ' Go for Stack,' the complex process of moving and lifting each of the space shuttle components into place for Endeavour's upcoming, inspiring 20-story vertical display,' said Jeffrey Rudolph, president and chief executive officer of the California Science Center. Over the next six months, the skirts will serve as a foundation for the rest of the space shuttle to be assembled, concluding with the mating of the winged orbiter Endeavour. Instead, a truck-mounted crane hoisted the 7.5-foot-tall by 18-foot-wide (2.3 by 5.5 meter) aft skirts, one by one, from where they had been parked outside of the California Science Center in Los Angeles into the adjacent construction site where the Samuel Oschin Air and Space Center will stand. This time though, the preparations were not for a launch into Earth orbit, and it occurred far away from NASA's Vehicle Assembly Building (VAB) in Florida.

On Thursday (July 20), the aft skirts for two solid rocket boosters were moved into place.

For the first time in 12 years, 3 months and 21 days, the stacking of a NASA space shuttle has begun again.

Space shuttle endeavour space shuttle