The Space Shuttle Endeavour sits atop NASA’s Shuttle Carrier Aircraft (SCA) at the NASA Dryden Flight Research Center at Edwards Air Force Base, Calif., Thursday, Sept. 20, 2012. Endeavour returned to its California roots after a wistful cross-country journey that paid homage to NASA workers and former Arizona Rep. Gabrielle Giffords and her astronaut husband. (AP Photo/Jae C. Hong) Read the full story here.

Space Shuttle Endeavour mounted on NASA’s Shuttle Carrier Aircraft, passes over the Golden Gate Bridge in San Francisco, Friday, Sept. 21, 2012. Endeavour is making a final trek across the country to the California Science Center in Los Angeles, where it will be permanently displayed. (AP Photo/Marcio Jose Sanchez)