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. -- Shuttle Launch Director Mike Leinbach, right, greets STS-134 Commander Mark Kelly, who arrived on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Mission Specialist Michael Fincke prepares to depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Fincke will return to NASA's Johnson Space Center in Houston to resume training for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. 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 stands in front of a T-38 jet on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Commander Mark Kelly arrives on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Mission Specialist Roberto Vittori, with the European Space Agency, prepares to depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Vittori will return to NASA's Johnson Space Center in Houston to resume training for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. 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 listens to Commander Mark Kelly address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Mission Specialist Andrew Feustel listens to Commander Mark Kelly address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Mission Specialist Michael Fincke listens to Commander Mark Kelly address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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, left, and Mission Specialist Roberto Vittori, with the European Space Agency, prepare to depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. The pair will return to NASA's Johnson Space Center in Houston to resume training for their upcoming mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Shuttle Launch Director Mike Leinbach, right, is on hand to greet STS-134 Mission Specialist Andrew Feustel who arrived on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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, left, and Mission Specialist Michael Fincke arrive on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour's STS-134 crew members pose for a group photo on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. From left, are Mission Specialists Greg Chamitoff, European Space Agency astronaut Roberto Vittori, Andrew Feustel, Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialist Michael Fincke. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Mission Specialist Roberto Vittori, with the European Space Agency, listens to Commander Mark Kelly address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Shuttle Launch Director Mike Leinbach, right, is on hand to greet STS-134 Pilot Greg H. Johnson who arrived on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Media snap photos and record the arrival of space shuttle Endeavour's STS-134 crew members on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Shuttle Launch Director Mike Leinbach greets STS-134 Mission Specialist Michael Fincke, who arrived on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Kelly will return to NASA's Johnson Space Center in Houston to resume training for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. 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, left, and Mission Specialist Roberto Vittori, with the European Space Agency, arrive on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 addresses the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Pilot Greg H. Johnson stands in front of a T-38 jet on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Mission Specialist Greg Chamitoff greets Dana Hutcherson, space shuttle Endeavour's NASA flow manager, after arriving on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour's STS-134 crew members pose for a group photo on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. From left, are Mission Specialists Greg Chamitoff, European Space Agency astronaut Roberto Vittori, Andrew Feustel, Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialist Michael Fincke. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour's STS-134 crew members address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. From left, are Mission Specialists Greg Chamitoff, European Space Agency astronaut Roberto Vittori, Andrew Feustel, Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialist Michael Fincke. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- STS-134 Mission Specialist Greg Chamitoff arrives on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Shuttle Launch Director Mike Leinbach, right, is on hand to greet STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, who arrived on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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 Mission Specialist Greg Chamitoff listens to Commander Mark Kelly address the media on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. While at Kennedy, space shuttle Endeavour's crew will participate in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training in preparation for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 19 at 7:48 p.m. EDT. 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, left, and Mission Specialist Michael Fincke prepare to depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. The pair will return to NASA's Johnson Space Center in Houston to resume training for their upcoming mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. 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 depart the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida aboard a T-38 jet. While at Kennedy, space shuttle Endeavour's crew participated in a launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Johnson will return to NASA's Johnson Space Center in Houston to resume training for the upcoming STS-134 mission. Endeavour and its six STS-134 crew members 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 International Space Station. This will be the final spaceflight for Endeavour. Launch is targeted for April 29 at 3:47 p.m. EDT. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett