In this handout provided by National Aeronautics and Space Administration (NASA), the STS-135 crew (L-R), Sandra Magnus, mission specialist, Rex Walheim, mission specialist, Doug Hurley, pilot, and Chris Ferguson, commander, ride in the Astrovan to launch pad 39A to board space shuttle Atlantis on July 8, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Florida. (Photo by Jerry Ross/NASA via Getty Images)

A NASA Emergency Response Team member, looks out while flying near the Vehicle Assembly Building before the launch of space shuttle Atlantis July 8, 2011 in Cape Canaveral, Florida. (Photo by Bill Ingalls/NASA via Getty Images)

In this handout from NASA, The exhaust plume from space shuttle Atlantis is seen through the window of a Shuttle Training Aircraft (STA) as it launches from launch pad 39A at the Kennedy Space Center July 8, 2011 in Cape Canaveral, Florida. This is the final launch of the space shuttle program, which began in 1981. (Photo by Dick Clark/NASA via Getty Images)

People watch as Space shuttle Atlantis lifts off on the last mission of the space shuttle program on July 8, 2011 in Titusville, Florida. Atlantis is headed to the space station. (Photo by Joe Raedle/Getty Images)