CAPE CANAVERAL, Fla. -- The STS-134 crew stands together on Launch Pad 39A in front of the towering external fuel tank and solid rocket boosters of space shuttle Endeavour, one day before its final flight, the STS-134 mission, to the International Space Station. From left are Mission Specialists Michael Fincke, Andrew Feustel; Pilot Greg H. Johnson, Commander Mark Kelly, European Space Agency astronaut Roberto Vittori and Mission Specialist Greg Chamitoff. Photo credit: NASA/Kim Shiflett Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the station. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Kim Shiflett

An faint profile outline of the space shuttle Endeavour is seen projected in the sky as powerful xenon lights illuminate launch pad 39a shortly after the rollback of the Rotating Service Structure (RSS) from Endeavour, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

201105150010hq (15 May 2011) --- The space shuttle Endeavour is seen on launch pad 39A after the rollback of the Rotating Service Structure (RSS), May 15, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for May 16 at 8:56 a.m. (EDT). Photo credit: NASA/Bill Ingalls

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen reflected in a puddle of water on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

201105150002hq (15 May 2011) --- The space shuttle Endeavour is seen on launch pad 39A after the rollback of the Rotating Service Structure (RSS), May 15, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for May 16 at 8:56 a.m. (EDT). Photo credit: NASA/Bill Ingalls

The space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

The space shuttle Endeavour is seen on launch pad 39a after the rollback of the Rotating Service Structure (RSS), Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)

CAPE CANAVERAL, Fla. -- The flags at Launch Pad 39A at NASA's Kennedy Space Center in Florida catch the offshore breeze as space shuttle Endeavour awaits liftoff. The rotating service structure (RSS) surrounds the shuttle for protection and to provide access but will be retracted before launch. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Launch is scheduled for April 29 at 3:47 p.m. EDT. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- A banner proclaims the sentiments of Kennedy's work force at Launch Pad 39A at NASA's Kennedy Space Center in Florida, as Space shuttle Endeavour awaits liftoff on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) surrounds the shuttle for protection and to provide access but will be retracted before launch. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Launch is scheduled for April 29 at 3:47 p.m. EDT. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour majestically awaits liftoff on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) surrounds the shuttle for protection and to provide access but will be retracted before launch. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Launch is scheduled for April 29 at 3:47 p.m. EDT. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.htmlPhoto credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour majestically awaits liftoff on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) surrounds the shuttle for protection and to provide access but will be retracted before launch. Endeavour and its crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Launch is scheduled for April 29 at 3:47 p.m. EDT. This will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.htmlPhoto credit: NASA/Frank Michaux

STS-134 Endeavour Sitting on Launch Pad 39A

STS-134 Endeavour Sitting on Launch Pad 39A

STS-134 Endeavour Sitting on Launch Pad 39A

STS-134 Endeavour Sitting on Launch Pad 39A

STS-134 LAUNCH L-1 CREW WITH FRIENDS AND FAMILY TOUR ENDEAVOUR AND PAD 39A

CAPE CANAVERAL, Fla. -- STS-134 Payloads Mission Manager Joe Delai talks to media with space shuttle Endeavour and its primary payload in the background on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- Crews move the primary payload for space shuttle Endeavour's STS-134 mission into the Payload Changeout Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour glistens in the sun on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The massive crawler-transporter that hauled the shuttle, attached to its external fuel tank and solid rocket boosters, to the pad March 10 remains on the crushed crawlerway rocks. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to move the primary payload for Endeavour's STS-134 mission into the pad's structure before installing it into the spacecraft's cargo bay. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

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. -- 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

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 to NASA's Hubble Space Telescope in 2009. 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 space station. Endeavour was scheduled to launch at 3:47 p.m. on April 29, but that attempt was scrubbed for at least 72 hours while engineers assess an issue associated with the shuttle's Auxiliary Power Unit 1. 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 glistens in the sun on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to move the primary payload for Endeavour's STS-134 mission into the pad's structure before installing it into the spacecraft's cargo bay. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour glistens in the sun on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to move the primary payload for Endeavour's STS-134 mission into the pad's structure before installing it into the spacecraft's cargo bay. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- Space shuttle Endeavour glistens in the sun on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to move the primary payload for Endeavour's STS-134 mission into the pad's structure before installing it into the spacecraft's cargo bay. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, moves past the Vehicle Assembly Building on its journey from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, moves past the Vehicle Assembly Building on its journey from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, is moved from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, moves past the Vehicle Assembly Building on its journey from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, is prepared for its move from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, arrives at Launch Pad 39A at NASA's Kennedy Space Center in Florida. Next, crews at the pad will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 (ELC-3) for space shuttle Endeavour's STS-134 mission, is prepared for its move from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, is moved from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

CAPE CANAVERAL, Fla. -- A canister, carrying the Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 for space shuttle Endeavour's STS-134 mission, is moved from the Canister Rotation Facility to Launch Pad 39A at NASA's Kennedy Space Center in Florida. At the pad, crews will move the payload into the Payload Ground Handling Mechanism (PGHM), and the rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components will be rotated back into place. The payload is scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Jack Pfaller

STS134-S-064 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-054 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-051 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-056 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-061 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-062 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-048 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-059 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-055 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-060 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-063 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-065 (16 May 2011) --- Photographed from a shuttle training aircraft, space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-052 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

STS134-S-053 (16 May 2011) --- Space shuttle Endeavour and its six-member STS-134 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts Mark Kelly, commander; Greg H. Johnson, pilot; Michael Fincke, Andrew Feustel, Greg Chamitoff and European Space Agency astronaut Roberto Vittori, all mission specialists. 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. STS-134 is the final spaceflight for Endeavour. Photo credit: NASA

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) has been replaced inside of space shuttle Endeavour. Located in Endeavour's aft avionics bay 5, the LCA-2, which distributes power to nine shuttle systems, is believed to have caused fuel line heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission and has been replaced. 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) has been replaced inside of space shuttle Endeavour. Located in Endeavour's aft avionics bay 5, the LCA-2, which distributes power to nine shuttle systems, is believed to have caused fuel line heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission and has been replaced. 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) has been replaced inside of space shuttle Endeavour. Located in Endeavour's aft avionics bay 5, the LCA-2, which distributes power to nine shuttle systems, is believed to have caused fuel line heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission and has been replaced. 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/Troy Cryder

JSC2011-E-044249 (16 May 2011) --- NASA astronauts Lee Archambault (left) and Barry Wilmore, both STS-134 spacecraft communicators (CAPCOM), are pictured at their console in the space shuttle flight control room in the Mission Control Center at NASA's Johnson Space Center during launch countdown activities a few hundred miles away in Florida, site of space shuttle Endeavour's STS-134 launch. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Photo credit: NASA

JSC2011-E-044250 (16 May 2011) --- NASA astronauts Lee Archambault (left) and Barry Wilmore, both STS-134 spacecraft communicators (CAPCOM), are pictured at their console in the space shuttle flight control room in the Mission Control Center at NASA's Johnson Space Center during launch countdown activities a few hundred miles away in Florida, site of space shuttle Endeavour's STS-134 launch. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Photo credit: NASA

JSC2011-E-044245 (16 May 2011) --- NASA astronauts Barry Wilmore (foreground) and Lee Archambault, both STS-134 spacecraft communicators (CAPCOM), are pictured at their console in the space shuttle flight control room in the Mission Control Center at NASA's Johnson Space Center during launch countdown activities a few hundred miles away in Florida, site of space shuttle Endeavour's STS-134 launch. Liftoff was at 8:56 a.m. (EDT) on May 16, 2011, from Launch Pad 39A at NASA's Kennedy Space Center. Photo credit: NASA

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section removes a cover to provide access for the removal and replacement of the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) is removed from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, workers gain entrance to space shuttle Endeavour's aft section as teams prepare to remove and replace the aft load control assembly-2 (ALCA-2). Located in the orbiter's aft avionics bay 5, the assembly is believed to have caused heaters on a fuel line for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A work station, a worker inspects the replacement Load Control Assembly-2 (LCA-2) which is being prepared for installation into Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. --The Load Control Assembly-2 (LCA-2) is outside at NASA Kennedy Space Center's Launch Pad 39A after it was removed from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- Barely visible inside space shuttle Endeavour's aft section, a technician at NASA Kennedy Space Center's Launch Pad 39A helps prepare for the upcoming removal and replacement of the aft load control assembly-2 (ALCA-2). Located in the orbiter's aft avionics bay 5, the assembly is believed to have caused heaters on a fuel line for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section removed a cover to provide access for the removal and replacement of the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, workers inside space shuttle Endeavour's aft section help prepare for the upcoming removal and replacement of the aft load control assembly-2 (ALCA-2). Located in the orbiter's aft avionics bay 5, the assembly is believed to have caused heaters on a fuel line for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- Boeing Space Operation's STS-134 Payload Flow Manager Bob Hart talks to media with space shuttle Endeavour and its primary payload in the background on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, technicians work to remove the Load Control Assembly-2 (LCA-2) from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section removes a cover to provide access for the removal and replacement of the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, technicians begin to remove the Load Control Assembly-2 (LCA-2) from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- A technician at NASA Kennedy Space Center's Launch Pad 39A crouches in space shuttle Endeavour's aft section, where teams are preparing to remove and replace the aft load control assembly-2 (ALCA-2). Located in the orbiter's aft avionics bay 5, the assembly is believed to have caused heaters on a fuel line for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- Crews move the primary payload for space shuttle Endeavour's STS-134 mission into the Payload Changeout Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to make the vertical move. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A work station, a replacement Load Control Assembly-2 (LCA-2) is being prepared for installation into Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section removes an insulating blanket and cover to provide access for the removal and replacement of the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. - 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 Kennedy Space Center's Launch Pad 39A, a technician makes his way across a platform in space shuttle Endeavour's aft section as work begins to remove and replace the aft load control assembly-2 (ALCA-2). Located in the orbiter's aft avionics bay 5, the assembly is believed to have caused heaters on a fuel line for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- Crews move the primary payload for space shuttle Endeavour's STS-134 mission into the Payload Changeout Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS) that protects the shuttle from the elements and provides access to its components is open to allow crews to make the vertical move. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, technicians inside space shuttle Endeavour's aft section test the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section removes a cover to provide access for the removal and replacement of the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, technicians inside space shuttle Endeavour's aft section test the Load Control Assembly-2 (LCA-2). Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- At NASA Kennedy Space Center's Launch Pad 39A, a worker inside space shuttle Endeavour's aft section is testing the Load Control Assembly-2 (LCA-2) for replacement. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. 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. -- The Load Control Assembly-2 (LCA-2) is outside at NASA Kennedy Space Center's Launch Pad 39A after it was removed from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) is removed from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- At NASA Kennedy Space Center's Launch Pad 39A, the Load Control Assembly-2 (LCA-2) is removed from inside space shuttle Endeavour's aft section. Located in the orbiter's aft avionics bay 5, the LCA-2 assembly, which feeds power to the fuel line heaters, is believed to have caused the heaters for Endeavour's auxiliary power unit-1 (APU-1) to fail April 29 during the first launch attempt for the STS-134 mission. The assembly 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/Troy Cryder

CAPE CANAVERAL, Fla. -- The rotating service structure (RSS) protecting space shuttle Endeavour from the elements and providing access to its components is open to allow crews to move the primary payload for the STS-134 mission into the Payload Changeout Room on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The Alpha Magnetic Spectrometer-2 (AMS) and Express Logistics Carrier-3 are scheduled to be installed into the shuttle's cargo bay March 25. Endeavour and its six-member STS-134 crew are targeted to lift off April 19 at 7:48 p.m. EDT to deliver the payload to the International Space Station. This is Endeavour's final scheduled mission. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA

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. -- 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. -- 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 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 space station. Endeavour was scheduled to launch at 3:47 p.m. on April 29, but that attempt was scrubbed for at least 72 hours while engineers assess an issue associated with the shuttle's Auxiliary Power Unit 1. 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. 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