CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson are ready to take off and perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson are ready to take off and perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly has completed touch-and-go landings and disembarks from a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly has completed touch-and-go landings in a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson prepares to perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson return after performing touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson has completed touch-and-go landings and disembarks from a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly and Pilot Greg H. Johnson are ready to take off and perform touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility runway at NASA's Kennedy Space Center in Florida. An STA is a Gulfstream II jet that is modified to mimic the shuttle's handling during the final phase of landing. Kelly and Johnson will practice landings as part of standard training before space shuttle Endeavour's launch to the International Space Station. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson performs touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's upcoming STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly performs touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's upcoming STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly completes touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly prepares to take flight in a Shuttle Training Aircraft (STA) to perform touch-and-go landings on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's upcoming STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson completes touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson gets behind the controls of a Shuttle Training Aircraft (STA) to perform touch-and-go landings on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly prepares to take flight in a Shuttle Training Aircraft (STA) to perform touch-and-go landings on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson completes touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly prepares to take flight in a Shuttle Training Aircraft (STA) to perform touch-and-go landings on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly performs touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's upcoming STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Pilot Greg H. Johnson performs touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's upcoming STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly gets behind the controls of a Shuttle Training Aircraft (STA) to perform touch-and-go landings on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Commander Mark Kelly completes touch-and-go landings aboard a Shuttle Training Aircraft (STA) on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. STAs are Gulfstream II business jets that are modified to mimic the shuttle's handling during the final phase of landing. Practice landings are part of standard training before space shuttle Endeavour's STS-134 launch to the International Space Station. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Targeted to launch April 19 at 7:48 p.m. EDT, they will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank, additional spare parts for the Dextre robotic helper and micrometeoroid debris shields to the space station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett