CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley perform touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The pilot and commander of every shuttle mission routinely practice landings aboard Shuttle Training Aircraft, which are Gulfstream II jets modified to mimic the shuttle's handling during the final phase of landing. The STS-135 flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley perform touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The pilot and commander of every shuttle mission routinely practice landings aboard Shuttle Training Aircraft, which are Gulfstream II jets modified to mimic the shuttle's handling during the final phase of landing. The STS-135 flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson, left, and Pilot Doug Hurley head out on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida to practice touch-and-go landings aboard two Shuttle Training Aircraft. The flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley are aboard Shuttle Training Aircraft to practice touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley perform touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The pilot and commander of every shuttle mission routinely practice landings aboard Shuttle Training Aircraft, which are Gulfstream II jets modified to mimic the shuttle's handling during the final phase of landing. The STS-135 flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley perform touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The pilot and commander of every shuttle mission routinely practice landings aboard Shuttle Training Aircraft, which are Gulfstream II jets modified to mimic the shuttle's handling during the final phase of landing. The STS-135 flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-135 Commander Chris Ferguson and Pilot Doug Hurley perform touch-and-go landings on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. The pilot and commander of every shuttle mission routinely practice landings aboard Shuttle Training Aircraft, which are Gulfstream II jets modified to mimic the shuttle's handling during the final phase of landing. The STS-135 flight crew of four arrived aboard T-38 training jets to watch two historic milestones of NASA's Space Shuttle Program -- the final landing of shuttle Endeavour, which will bookend its STS-134 mission to the International Space Station, and the final rollout of their vehicle, space shuttle Atlantis, to Launch Pad 39A. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of the shuttle program. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/index.html. Photo credit: NASA/Kim Shiflett