JOINT BASE ANDREWS, Md., -- Last flight of the Shuttle Discovery flys over Joint Base Andrews, Md. on April 17, 2012. Discovery pigy backed a ride on a jumbo 747 from NASA KTTS Landing Facility (U.S. Air Force photo by Staff Sgt. Sophia Piellusch) A NASA Shuttle Carrier Aircraft carrying the Space Shuttle Discovery performs a fly by, April 17, 2012 at Joint Base Andrews, Md. The aircraft landed at Washington Dulles International Airport in Sterling, Va., before its transfer to the National Air and Space Museum. Discovery completed 39 missions, spent 365 days in space, orbited the Earth 5,830 times, and traveled 148,221,675 miles .(U.S. Air Force photo/Senior Airman Katie Spencer) Space Shuttle Discovery flys by JBA by Senior Airman Katie Spencer 459th Air Refueling Wing Public Affairs 4/17/2012 - JOINT BASE ANDREWS, Md.  -- A NASA Shuttle Carrier Aircraft carrying the Space Shuttle Discovery performs a fly by, April 17, 2012 at Joint Base Andrews, Md. The aircraft landed at Washington Dulles International Airport in Sterling, Va., before its transfer to the National Air and Space Museum. Discovery completed 39 missions, spent 365 days in space, orbited the Earth 5,830 times, and traveled 148,221,675 miles.