Stock Photo - Space shuttle Atlantis and its four-member STS-135 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 11:29 a.m. (EDT) on July 8, 2011 from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Chris Ferguson, commander; Doug Hurley, pilot; Sandy Magnus and Rex Walheim, both mission specialists. STS-135 will deliver the Raffaello multi-purpose logistics module packed with supplies and spare parts for the space station. Atlantis also carries the Robotic Refueling Mission experiment that will investigate the potential for robotically refueling existing satellites in orbit. In addition, Atlantis will return with a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of NASA's Space Shuttle Program.