Crane workers work to position a half track into place during assembly of a second crane, Thursday, April 12, 2012, at the Apron W area of Washington Dulles international Airport in Sterling, Va. Workers are preparing the cranes to be in position to demate space shuttle Discovery from the 747 Shuttle Carrier Aircraft (SCA) once it arrives early next week. Discovery, the first orbiter retired from NASAâs shuttle fleet, completed 39 missions, spent 365 days in space, orbited the Earth 5,830 times, and traveled 148,221,675 miles. NASA will transfer Discovery to the National Air and Space Museum to begin its new mission to commemorate past achievements in space and to educate and inspire future generations of explorers. Photo Credit: (NASA/Paul E. Alers)
