Space Shuttle Discovery leaves the Vehicle Assembly Building (VAB) on its way to the Orbiter Processing Facility at Kennedy Space Center August 11, 2011 in Cape Canaveral, Florida. Space Shuttles Endeavour and Discovery switched buildings as they are being decommissioned with the end of the Shuttle program. (Photo by Roberto Gonzalez/Getty Images)

In this handout image provided by the European Space Agency (ESA) and NASA, the International Space Station and the docked space shuttle Endeavour orbit Earth during Endeavour's final sortie on May 23, 2011 in Space. Italian astronaut Paolo Nespoli captured the first-ever images of an orbiter docked to the International Space Station from the viewpoint of a departing vessel as he returned to Earth in a Soyuz capsule. (Photo by Paolo Nespoli - ESA/NASA via Getty Images)

Back dropped by planet Earth the International Space Station (ISS) is seen from NASA space shuttle Endeavour after the station and shuttle began their post-undocking relative separation May 29, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on the last leg of its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, has lead mission STS-134 as it delivered the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)

Crowds gather and watch the launch of NASA space shuttle Endeavour from Kennedy Space Center on the beach May 16, 2011 in Cocoa Beach, Florida. (Photo by Roberto Gonzalez/Getty Images)