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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, the Closeout Crew helps STS-134 Commander Mark Kelly put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

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. -- During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, members of the STS-134 crew check out a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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 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. -- The STS-134 Pilot Greg H. Johnson participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialists Roberto Vittori, with the European Space Agency, left, and Michael Fincke touch fists as they prepare to board space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Jim Grossmann

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. -- During a simulated launch countdown, STS-134 Pilot Greg H. Johnson checks the fit of his helmet in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Johnson and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. - Space shuttle Endeavour's STS-134 crew members pose for a group photo in front of an M113 armored personnel carrier at NASA's Kennedy Space Center in Florida. An M113 is kept at the foot of the launch pad in case an emergency exit from the pad is needed and every shuttle crew is trained on driving the vehicle before launch. From left, are Mission Specialists Greg Chamitoff, European Space Agency astronaut Roberto Vittori and Andrew Feustel, Pilot Greg H. Johnson, Mission Specialist Michael Fincke, and Commander Mark Kelly. 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 signs the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, front, and a fellow crewmate make their way toward a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Andrew Feustel checks the fit of his helmet in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Feustel and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Greg Chamitoff checks the fit of his bright-orange, launch-and-entry suit in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Chamitoff and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- The STS-134 Commander Mark Kelly participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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 gives a thumbs-up as he takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. -- The STS-134 Mission Specialist Greg Chamitoff participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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. -- The STS-134 crew answers media questions in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. From left, are Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialists Michael Fincke, European Space Agency astronaut Roberto Vittori, Andrew Feustel, and Greg Chamitoff. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialists Roberto Vittori, with the European Space Agency, front, and Michael Fincke, Pilot Greg H. Johnson, and Commander Mark Kelly make their way toward a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. - At NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Greg Chamitoff, left, and Commander Mark Kelly take a break from training on the M113 armored personnel carrier at NASA's Kennedy Space Center in Florida. An M113 is kept at the foot of the launch pad in case an emergency exit from the pad is needed and every shuttle crew is trained on driving the vehicle before launch. 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. - Space shuttle Endeavour's STS-134 crew members participate in M113 armored personnel carrier training at NASA's Kennedy Space Center in Florida. An M113 is kept at the foot of the launch pad in case an emergency exit from the pad is needed and every shuttle crew is trained on driving the vehicle before launch. 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. -- During a simulated launch countdown, STS-134 Mission Specialist Andrew Feustel checks the fit of his bright-orange, launch-and-entry suit in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Feustel and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, hops in a slidewire basket that would take him to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Discovery is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, the Closeout Crew helps STS-134 Mission Specialist Michael Fincke put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

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 Commander Mark Kelly takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialists Roberto Vittori, with the European Space Agency, left, and Michael Fincke, and Pilot Greg H. Johnson check out a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- The STS-134 crew members pose in front of the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. From left, are Mission Specialists Greg Chamitoff, Michael Fincke, Andrew Feustel, Pilot Greg H. Johnson, Mission Specialist Roberto Vittori, with the European Space Agency, and Commander Mark Kelly. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Commander Mark Kelly prepares to board space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Jim Grossmann

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 Mission Specialist Roberto Vittori, with the European Space Agency, gives a thumbs-up in the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida. The Closeout Crew is helping Vitorri put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

CAPE CANAVERAL, Fla. -- During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Andrew Feustel hops in a slidewire basket that would take him to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Discovery is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, checks the fit of his helmet in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Vittori and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Commander Pilot Greg H. Johnson checks the fit of his bright-orange, launch-and-entry suit in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Johnson and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- The STS-134 crew answers media questions in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. From left, are Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialists Michael Fincke, European Space Agency astronaut Roberto Vittori, Andrew Feustel, and Greg Chamitoff. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, checks the fit of his bright-orange, launch-and-entry suit in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Vittori and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialists Andrew Feustel and Greg Chamitoff make their way toward a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- The STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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. -- During a simulated launch countdown, STS-134 Commander Mark Kelly checks the fit of his bright-orange, launch-and-entry suit and communications cap in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Kelly and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Roberto Vittori, with the European Space Agency, prepares to board space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Jim Grossmann

CAPE CANAVERAL, Fla. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Pilot Greg H. Johnson prepares to board space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Jim Grossmann

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 Mission Specialist Michael Fincke signs the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. 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 gives a thumbs-up as he takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. -- The STS-134 Commander Mark Kelly participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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, 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. -- The STS-134 Mission Specialist Andrew Feustel participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, the Closeout Crew helps STS-134 Pilot Greg H. Johnson put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

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. -- During a simulated launch countdown, the STS-134 crew walks out of the Operations and Checkout Building to the waiting Astrovan at NASA's Kennedy Space Center in Florida. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members ride to Kennedy's Launch Pad 39A in the silver vehicle and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. From front, left to right, are STS-134 Pilot Greg H. Johnson, Commander Mark Kelly; second row; astronaut Roberto Vittori from the European Space Agency and Mission Specialist Mike Fincke; third row are Mission Specialists Greg Chamitoff and Andrew Feustel. Endeavour's six crew members are 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 International 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. -- 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. -- During a simulated launch countdown, the STS-134 crew walks out of the Operations and Checkout Building to the waiting Astrovan at NASA's Kennedy Space Center in Florida. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members ride to Kennedy's Launch Pad 39A in the silver vehicle and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. From right to left are, Commander Mark Kelly, Mission Specialist Mike Fincke, Pilot Greg H. Johnson, Roberto Vittori, European Space Agency astronaut, and Mission Specialists Andrew Feustel and Greg Chamitoff. Endeavour's six crew members are 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 International 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 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. - STS-134 Mission Specialist Greg Chamitoff gives a thumbs-up as he takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. -- 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. -- The STS-134 crew answers media questions in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. From left, are Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialists Michael Fincke, European Space Agency astronaut Roberto Vittori, Andrew Feustel, and Greg Chamitoff. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International 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 Andrew Feustel gives a thumbs-up as he takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, the Closeout Crew helps STS-134 Mission Specialist Andrew Feustel put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

CAPE CANAVERAL, Fla. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Andrew Feustel prepares to board space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Jim Grossmann

CAPE CANAVERAL, Fla. -- The STS-134 Mission Specialist Michael Fincke participates in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialists Greg Chamitoff, left, and Andrew Feustel hop in a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Discovery is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Michael Fincke checks the fit of his helmet in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Fincke and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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 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 Mission Specialist Roberto Vittori, with the European Space Agency, signs the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. 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 signs the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. 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. - At NASA's Kennedy Space Center in Florida, the STS-134 crew takes a break from a simulated launch countdown and simulated pad emergency to take a group photo on the 195-foot level of Launch Pad 39A. From left are, Commander Mark Kelly, Pilot Greg H. Johnson, and Mission Specialists Michael Fincke, Andrew Feustel, Roberto Vittori, with the European Space Agency, and Greg Chamitoff. The simulations are part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Mission Specialist Michael Fincke checks the fit of his bright-orange, launch-and-entry suit in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Fincke and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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. -- During a simulated launch countdown, STS-134 Commander Mark Kelly checks the fit of his bright-orange, launch-and-entry suit and communications cap in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Kelly and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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 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 Mission Specialist Roberto Vittori, with the European Space Agency, gives a thumbs-up as he takes his seat aboard space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT) on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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. - During a simulated pad emergency on Launch Pad 39A at NASA's Kennedy Space Center in Florida, members of the STS-134 crew check out a slidewire basket that would take them to a safe bunker below the pad in an unlikely emergency situation. The emergency training while aboard space shuttle Endeavour is part of a week-long Terminal Countdown Demonstration Test (TCDT). Endeavour's six crew members are 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 International 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, 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. -- In the White Room of Launch Pad 39A at NASA's Kennedy Space Center in Florida, the Closeout Crew helps STS-134 Mission Specialist Greg Chamitoff put on the parachute for his launch-and-entry suit before he boards space shuttle Endeavour during the Terminal Countdown Demonstration Test (TCDT). Behind Chamitoff is Pilot Greg H. Johnson. Part of TCDT includes practicing the final hours of a real launch day when astronauts put on their launch-and-entry suits, ride to the pad in the Astrovan and strap into the shuttle. Endeavour's six crew members are 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 International 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/Kevin O'Connell

CAPE CANAVERAL, Fla. -- The STS-134 Commander Mark Kelly and Pilot Greg H. Johnson participate in a media question-and-answer session in the Press Site TV auditorium at NASA's Kennedy Space Center in Florida. The crew was scheduled to answer questions at Launch Pad 39A, where space shuttle Endeavour is awaiting liftoff, but severe storms associated with a frontal system passing over Central Florida brought the media event indoors. 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 International Space Station. This is 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 Andrew Feustel signs the space shuttle wall tribute in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program. Endeavour's six crew members are at Kennedy for the launch countdown dress rehearsal called the Terminal Countdown Demonstration Test (TCDT) and related training. Endeavour is targeted to launch April 19 at 7:48 p.m. EDT on its final spaceflight mission. 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. -- During a simulated launch countdown, STS-134 Mission Specialist Greg Chamitoff checks the fit of his helmet in the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. Next, Chamitoff and his crewmates will walk out to the waiting Astrovan. As part of the Terminal Countdown Demonstration Test (TCDT), the crew members will ride to the pad in their silver Astrovan and strap into space shuttle Endeavour to practice the steps that will be taken on launch day. Endeavour's six crew members are 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 International 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