Space Shuttle Discovery Final Flight | Landing at Dulles

STERLING, VA - APRIL 17: In this handout provided by NASA, space shuttle Discovery is tethered to the back of NASA 905 Shuttle Carrier Aircraft (SCA), a modified Boeing 747 jumbo jet, as it approaches the runway at Washington Dulles International Airport April 17, 2012 in Sterling, Virginia. The oldest and most traveled vehicle in NASA's space shuttle program, Discovery will be placed on permanent display at the Smithsonian National Air and Space Museum Steven F. Udvar-Hazy Center. (Photo by Paul E. Alers/NASA via Getty Images)