Space Shuttle Discovery Final Flight | Washington, D.C.

CHANTILLY, VA - APRIL 17: Space Shuttle Discovery, mounted atop a 747 shuttle carrier aircraft, sits on the tarmac after it landed at Washington Dulles International Airport during the final trip to its retirement place April 17, 2012 in Chantilly, Virginia. The longest-serving orbiter in the space shuttle fleet was flown from Kennedy Space Center in Florida to the Washington, DC, area to be transferred to the Smithsonian National Air and Space Museum and will be placed on display in the museum's Steven F. Udvar-Hazy Center. (Photo by Alex Wong/Getty Images)