CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, the rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Roberto Vittori with the European Space Agency, seen here, will be making his third trip to the International Space Station. His first mission was in 2002 and second in 2005, both of which were launched aboard a Russian Soyuz spacecraft. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 at 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 through the crew hatch in the background. Members of the Closeout Crew, in white uniforms, are there to assist astronauts with their launch-and-entry suits and the boarding process. Vittori will be making his third trip to the International Space Station. His first mission was in 2002 and second in 2005, both of which were launched aboard a Russian Soyuz spacecraft. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - NASA astronaut Shannon Walker, left and Kennedy Space Center Director Bob Cabana talk to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. - NASA Administrator Charlie Bolden talks to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kurtis Korwan

CAPE CANAVERAL, Fla. -- The American flag sways in the breeze as space shuttle Endeavour launches on the STS-134 mission to the International Space Station. The shuttle and its six-member crew lifted off from Launch Pad 39A at NASA's Kennedy Space Center in Florida on time at 8:56 a.m. EDT on May 16. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Troy Cryder

CAPE CANAVERAL, Fla. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida await the liftoff of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Andrew Feustel, seen here, last flew on a mission to NASA's Hubble Space Telescope in 2009. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 six STS-134 astronauts, dressed in their orange launch-and-entry suits, wave to news media and other spectators as they walk toward the Astrovan parked in front of the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. The modified Airstream recreational vehicle, which has transported astronauts to their spacecraft since 1984, will take the crew to Launch Pad 39A. Leading the way are Pilot Greg H. Johnson, front left, and Commander Mark Kelly, front right. Behind Johnson are Mission Specialists Roberto Vittori with the European Space Agency and Greg Chamitoff. Behind Kelly are Mission Specialists Michael Fincke and Andrew Feustel. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida as the rotating service structure (RSS) moves away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Commander Mark Kelly, seen here, last commanded space shuttle Discovery during its STS-124 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- Rising on twin columns of fire, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida beginning its final flight, the STS-134 mission, to the International Space Station. Launch was on time at 8:56 a.m. EDT on May 16. STS-134 and its six-member crew will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. - Space shuttle Endeavour, the giant external fuel tank and twin solid rocket boosters bask in the sunlight as the rotating service structure (RSS) moves away on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, the rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 watches space shuttle Endeavour soar into space from Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 monitors the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Behind Leinbach, from left, are STS-134 Launch Commentator George Diller, Endeavour's NASA Flow Director Dana Hutcherson and STS-134 Assistant Launch Director Pete Nickolenko. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Tony Gray and Tom Farrar

CAPE CANAVERAL, Fla. -- In the White Room at Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Pilot Greg H. Johnson, left, and Mission Specialist Greg Chamitoff prepare to board space shuttle Endeavour through the crew hatch in the background. Members of the Closeout Crew, in white uniforms, are there to assist astronauts with their launch-and-entry suits and the boarding process. Johnson piloted space shuttle Endeavour during its STS-123 mission in 2008. Chamitoff last served as flight engineer and science officer aboard the International Space Station in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. -- Kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission to the International Space Station, on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida watch as space shuttle Endeavour soars skyward. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Commander Mark Kelly, seen here, last commanded space shuttle Discovery during its STS-124 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- As the sun rises and paints a colorful skyline across NASA's Kennedy Space Center in Florida, media set up their cameras at the countdown clock in the Launch Complex 39 area. At 8:56 a.m. EDT on May 16, space shuttle Endeavour and its six-member STS-134 crew are scheduled to lift off Launch Pad 39A on a mission to the International Space Station. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. This will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Troy Cryder

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Pilot Greg H. Johnson, seen here, last piloted space shuttle Endeavour during its STS-123 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida watch as space shuttle Endeavour soars skyward. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. -- Media capture the launch of space shuttle Endeavour on the STS-134 mission to the International Space Station from the Press Site at NASA's Kennedy Space Center in Florida. The shuttle and its six-member crew lifted off on time at 8:56 a.m. EDT on May 16. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Troy Cryder

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Michael Fincke, seen here, last served as a member of the Expedition 18 crew of the International Space Station in 2009. This will be Fincke's first flight aboard a space shuttle. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 NASA Flow Director Dana Hutcherson, left, STS-134 Assistant Launch Director Pete Nickolenko and Shuttle Launch Director Mike Leinbach monitor the STS-134 countdown in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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, left, STS-134 Assistant Launch Director Pete Nickolenko and Endeavour's NASA Flow Director Dana Hutcherson give a round of applause to the launch controllers in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Andrew Feustel, seen here, last flew on a mission to NASA's Hubble Space Telescope in 2009. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - Following a successful launch, space shuttle Endeavour NASA Flow Director Dana Hutcherson congratulates Shuttle Launch Director Mike Leinbach, right, and Closeout Crew Lead Travis Thompson in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- Rising on twin columns of fire and kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida beginning its final flight, the STS-134 mission, to the International Space Station. Launch was on time at 8:56 a.m. EDT on May 16. STS-134 and its six-member crew will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida watch as space shuttle Endeavour soars skyward. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. - Shuttle Launch Director Mike Leinbach, standing, and his launch team monitor the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida await the liftoff of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Pilot Greg H. Johnson, seen here, last piloted space shuttle Endeavour during its STS-123 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- Rising on twin columns of fire and kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from its seaside launch pad at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. - Joe Dowdy, special operations manager at NASA's Kennedy Space Center, talks to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Tony Gray and Tom Farrar

CAPE CANAVERAL, Fla. - The giant external fuel tank and twin solid rocket boosters attached to space shuttle Endeavour bask in the sunlight as the rotating service structure (RSS) moves away on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - NASA Kennedy Space Center Director Bob Cabana talks to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kurtis Korwan

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, Public Affairs Officer George Diller, Kennedy Director Bob Cabana, Space Shuttle Program Launch Integration Manager Mike Moses and Shuttle Launch Director Mike Leinbach participate in a news conference following the April 29 scrubbed launch attempt of space shuttle Endeavour. During the STS-134 countdown, fuel line heaters for Endeavour's auxiliary power unit-1 (APU-1) failed. Technicians later discovered that the Load Control Assembly-2 (LCA-2), which distributes power to nine shuttle systems, was the cause of the failure reading. The LCA-2 located in Endeavour's aft section will be replaced and systems will be retested before the launch is rescheduled. STS-134 will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. The mission also 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, left, STS-134 Assistant Launch Director Pete Nickolenko and Endeavour's NASA Flow Director Dana Hutcherson give a round of applause to the launch controllers in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - The giant external fuel tank and twin solid rocket boosters attached to space shuttle Endeavour bask in the sunlight as the rotating service structure (RSS) moves away on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Shuttle Launch Director Mike Leinbach, left, and STS-134 Assistant Launch Director Pete Nickolenko monitor the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- As the sun rises and paints a colorful skyline across NASA's Kennedy Space Center in Florida, media set up their cameras at the countdown clock in the Launch Complex 39 area. At 8:56 a.m. EDT on May 16, space shuttle Endeavour and its six-member STS-134 crew are scheduled to lift off Launch Pad 39A on a mission to the International Space Station. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. This will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Troy Cryder

CAPE CANAVERAL, Fla. -- Rising on twin columns of fire, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida beginning its final flight, the STS-134 mission, to the International Space Station. Launch was on time at 8:56 a.m. EDT on May 16. STS-134 and its six-member crew will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - NASA Administrator Charlie Bolden, right, monitors the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. To Bolden's right is Associate Administrator for Space Operations Bill Gerstenmaier. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. - Water bags, called red water sausages, are revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. The bags will dampen the wave of sound energy that is reflected back up toward space shuttle Endeavour when the solid rocket boosters ignite during launch. They suppress the powerful pulse of pressure to prevent dangerous stress on the wings of the shuttle. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Spectators at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida watch as space shuttle Endeavour soars skyward. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kurtis Korwan

CAPE CANAVERAL, Fla. -- Rising on twin columns of fire and kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida beginning its final flight, the STS-134 mission, to the International Space Station. Launch was on time at 8:56 a.m. EDT on May 16. STS-134 and its six-member crew will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. - NASA astronaut Shannon Walker talks to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kurtis Korwan

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. -- Rising on twin columns of fire and kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from its seaside launch pad at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, the rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Under a vividly painted blue sky, space shuttle Endeavour awaits liftoff on Launch Pad 39A at NASA's Kennedy Space Center in Florida. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, the rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Greg Chamitoff, seen here, last served as flight engineer and science officer aboard the International Space Station in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. -- In the White Room at 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 through the crew hatch in the background. Kelly last commanded space shuttle Discovery during its STS-124 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - Water bags, called red water sausages, are revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. The bags will dampen the wave of sound energy that is reflected back up toward space shuttle Endeavour when the solid rocket boosters ignite during launch. They suppress the powerful pulse of pressure to prevent dangerous stress on the wings of the shuttle. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Michael Fincke, seen here, last served as a member of the Expedition 18 crew of the International Space Station in 2009. This will be Fincke's first flight aboard a space shuttle. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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, the giant external fuel tank and twin solid rocket boosters bask in the sunlight as the rotating service structure (RSS) moves away on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida as the rotating service structure (RSS) moves away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, the rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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. - NASA Administrator Charlie Bolden, right, monitors the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from its seaside launch pad at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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 at Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Mission Specialist Michael Fincke prepares to board space shuttle Endeavour through the crew hatch in the background. Members of the Closeout Crew, in white uniforms, are there to assist astronauts with their launch-and-entry suits and the boarding process. Fincke last served as a member of the Expedition 18 crew of the International Space Station in 2009. This will be Fincke's first flight aboard a space shuttle. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - A "Go Endeavour" banner adorns the perimeter gate on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS), which has been providing weather protection and access to space shuttle Endeavour while it awaits lift off on the pad, soon will move away in preparation for launch. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Tony Gray and Tom Farrar

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida as the rotating service structure (RSS) moves away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- Kicking up a trail of smoke and steam, space shuttle Endeavour lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida beginning its final flight, the STS-134 mission, to the International Space Station. Launch was on time at 8:56 a.m. EDT on May 16. STS-134 and its six-member crew will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. - NASA Kennedy Space Center Director Bob Cabana talks to a crowd of spectators gathered at the Banana Creek Viewing Site near the Saturn V Center at NASA's Kennedy Space Center in Florida to watch the launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Chad Baumer

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida as the rotating service structure (RSS) moves away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida as the rotating service structure (RSS) moves away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. - Backdropped by a beautiful blue sky and the crystal-clear Atlantic Ocean, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Greg Chamitoff, seen here, last served as flight engineer and science officer aboard the International Space Station in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, space shuttle Endeavour's STS-134 astronauts put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Roberto Vittori with the European Space Agency, seen here, will be making his third trip to the International Space Station. His first mission was in 2002 and second in 2005, both of which were launched aboard a Russian Soyuz spacecraft. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- In the White Room at Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Pilot Greg H. Johnson prepares to board space shuttle Endeavour through the crew hatch in the background. Members of the Closeout Crew, in white uniforms, are there to assist astronauts with their launch-and-entry suits and the boarding process. Johnson piloted space shuttle Endeavour during its STS-123 mission in 2008. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - Marshall Space Flight Director Robert Lightfoot, left, Kennedy Space Center Director Bob Cabana and Johnson Space Center Director Mike Coats monitor the countdown to liftoff of space shuttle Endeavour in Firing Room 4 of the Launch Control Center. Endeavour lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- Amid the tranquility of a wildlife refuge, space shuttle Endeavour rumbles off Launch Pad 39A at NASA's Kennedy Space Center in Florida. Endeavour began its final flight, the STS-134 mission, to the International Space Station on time at 8:56 a.m. EDT on May 16. Endeavour and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Kennedy coexists with the Merritt Island National Wildlife Refuge, habitat to more than 310 species of birds, 25 mammals, 117 fish and 65 amphibians and reptiles. Photo credit: NASA/Sandra Joseph and Kevin O'Connell

CAPE CANAVERAL, Fla. - NASA Administrator Charlie Bolden congratulates the launch team in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida following the successful launch of space shuttle Endeavour. The shuttle lifted off on its STS-134 mission to the International Space Station on time at 8:56 a.m. EDT on May 16. The shuttle and its six-member crew are embarking on a mission to deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the space station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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 six STS-134 astronauts, dressed in their orange launch-and-entry suits, wave to news media and other spectators in front of the Astrovan parked in front of the Operations and Checkout Building at NASA's Kennedy Space Center in Florida. The modified Airstream recreational vehicle, which has transported astronauts to their spacecraft since 1984, will take the crew to Launch Pad 39A. From left, are Mission Specialists Greg Chamitoff, Andrew Feustel, Roberto Vittori with the European Space Agency and Michael Fincke, Pilot Greg H. Johnson, and Commander Mark Kelly. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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 rotating service structure (RSS) moves away from space shuttle Endeavour on Launch Pad 39A. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 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, space shuttle Endeavour is revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was complete at 12:24 p.m. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- The American flag sways in the breeze as space shuttle Endeavour soars into the sky on the STS-134 mission to the International Space Station. The shuttle and its six-member crew lifted off from Launch Pad 39A at NASA's Kennedy Space Center in Florida on time at 8:56 a.m. EDT on May 16. STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Endeavour's first launch attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Troy Cryder