The final flight of Endeavour

The space shuttle Endeavour is seen on launch pad 39A at the Kennedy Space Center in Cape Canaveral, Fla. The final flight of Endeavour - and the next-to-last of any mission in NASA's shuttle program - was originally scheduled for April 29 but was delayed until mid-May.

The space shuttle Endeavour on its launch pad 39A, a day before its scheduled 8:56 a.m. launch on May 15, 2011. 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.

Mark Kelly, commander of the space shuttle Endeavour, walks past a T-38 jet after arriving at Kennedy Space Center with his fellow crew members in Cape Canaveral, Fla..

Ariz. Rep. Gabrielle Giffords (spotlighted) boards plane in Houston to fly to Florida April 27, 2011 to attend scheduled April 28 launch of space shuttle Endeavour with her husband, Capt. Mark Kelly, at the helm. It was to be Endeavour's last flight and t — CBS

Ariz. Rep. Gabrielle Giffords (spotlighted) boards a plane in Houston to fly to Florida on April 27, 2011 to attend the scheduled launch of space shuttle Endeavour with her husband, Capt. Mark Kelly, at the helm. Giffords was recovering from wounds suffered in a January assassination attempt in Tucson in which six people were shot dead. Doctors gave her clearance to attend her husband's launch. After the April 29 launch was scrubbed, Giffords' chief of staff said she was determined to attend the subsequent attempt - and she did.

The crew of Space Shuttle Endeavour walk to their transport vehicle to be taken to the shuttle May 16, 2011 at the Kennedy Space Center in Florida. From left: Pilot Gregory Johnson, Roberto Vittori of Italy, Greg Chamitoff, Commander Mark Kelly, Andrew Feustel and Michael Fincke.

Spectators line a pier to view the space shuttle Endeavour's final launch, May 15, 2011 in Titusville, Florida. Approximately half a million people witnessed the liftoff.

Blast-off for Endeavour, at Kennedy Space Center at Cape Canaveral, Fla., Monday, May 16, 2011.

Space shuttle Endeavour lifts off from Kennedy Space Center in Cape Canaveral, Fla., Monday, May 16, 2011.

The space shuttle Endeavour lifts off from Kennedy Space Center in Cape Canaveral, Fla., Monday, May 16, 2011.

Space shuttle Endeavour launches at Cape Canaveral, Fla., Monday, May 16, 2011.

The space shuttle Endeavour lifts off from Kennedy Space Center in Cape Canaveral, Fla., Monday, May 16, 2011.

Craig Rubadoux,AP Photo/Daytona Beach News-Journal

Space shuttle Endeavour flies past the U.S. and STS-134 mission flags after launch at Cape Canaveral, Fla., on Monday, May 16, 2011.

The space shuttle Endeavour lifts off from Kennedy Space Center in Cape Canaveral, Fla., Monday, May 16, 2011, beginning its 14-day mission to the International Space Station.

Photographers capture Endeavour as it pierces the clouds and disappears after launch at Cape Canaveral, Fla., on Monday, May 16, 2011.

Joy Lewis holds her son Kaleb Lewis, 1, of Stafford, Va., as they watch the launch of space shuttle Endeavour from the Rocket Garden at the Kennedy Space Center Visitors Center, Monday, May 16, 2011, in Cape Canaveral, Fla.

Space shuttle Endeavour and its six-member crew head toward Earth orbit, May 16, 2011.

Photographed from a shuttle training aircraft, the Endeavour is seen breaking through clouds as it heads toward Earth orbit, May 16, 2011.

Stefanie Gordon was traveling on Delta Flight 2285 from New York's LaGuardia airport to West Palm Beach in Florida when she snapped a picture and video of Endeavour with her camera phone, and posted it to her Twitter account, stefmara. "The captain made an announcement that we would probably see it. I really couldn't hear what he was saying and then all of a sudden people started getting up and going over to the windows," Gordon told CBS News. "It was amazing."

The launch of Endeavour was captured by a camera aboard a student science project balloon, the Senatobia-1, at an altitude of 64,000 feet. The trail of Endeavour's rockets can be seen at right.

The STS-134 external fuel tank is seen during its release from Endeavour, following the successful launch on May 16, 2011. A camera in the umbilical well took the picture.

NASA astronaut Greg Chamitoff, STS-134 mission specialist, gets help donning a training version of his Extravehicular Mobility Unit (EMU) spacesuit in preparation for a spacewalk training session in the waters of the Neutral Buoyancy Laboratory (NBL) at the Sonny Carter Training Facility near NASA's Johnson Space Center.

Pilot Gregory Johnson, astronaut Michael Fincke, European Space Agency astronaut Roberto Vittori — NASA

Attired in training versions of their shuttle launch and entry suits, pilot Gregory H. Johnson (left), mission specialist Michael Fincke (right background), and European Space Agency mission specialist Roberto Vittori participate in a training session on the flight deck of the Full Fuselage Trainer (FFT) in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center, Feb. 3, 2011.

European Space Agency astronaut Roberto Vittori, NASA astronaut Andrew Feustel — NASA

European Space Agency astronaut Roberto Vittori (right) and NASA astronaut Andrew Feustel participate in an exercise in the systems engineering simulator of the Avionics Systems Laboratory, at NASA's Johnson Space Center, March 23, 2011. The facility includes moving scenes of full-sized International Space Station components over a simulated Earth.

STS-134 mission specialist Andrew Feustel, attired in a training version of his Extravehicular Mobility Unit (EMU) spacesuit, awaits the start of a spacewalk training session in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center.

A view from Endeavour as the astronauts receive their first wake-up call in space - U2's "Beautiful Day."

On the left side of this photo showing Endeavour's vertical stabilizer and cargo bay is the Orbiter Boom Sensor System (OBSS), a 50-foot boom carried onboard each of NASA's space shuttles. At the far end of the boom is an instrumentation package of cameras and lasers used to scan the leading edges of the wings, the nose cap, and the crew compartment after each lift-off and before each landing to check for tile damage.

STS-134 commander Mark Kelly gets down to work soon after Endeavour reaches Earth orbit. Kelly is seated at the commander's station on the shuttle's forward flight deck.

The International Space Station (ISS) as photographed by the Endeavour crew as the two spacecraft were preparing to link up in Earth orbit. The "extra" glares and reflections are inside Endeavour's crew cabin.

STS-134 commander Mark Kelly (left) and mission specialist Andrew Feustel are pictured on the aft flight deck of Endeavour during rendezvous and docking operations with the International Space Station on flight day three.

NASA astronaut Greg Chamitoff, STS-134 mission specialist, uses a computer on the aft flight deck of space shuttle Endeavour during rendezvous and docking operations with the International Space Station on flight day three.

The space shuttle Endeavour conducts a flip maneuver to allow inspection of its heat shield tiles, prior to docking at the International Space Station.

This close-up view of the crew cabin of space shuttle Endeavour was provided by an Expedition 27 crew member during a survey of the approaching STS-134 vehicle, May 18, 2011, prior to docking with the International Space Station. The station crew member used a digital still camera with an 800mm focal length, as the two spacecraft were approximately 600 feet apart.

Astronauts aboard the International Space Station photograph the shuttle Endeavour's heat shield tiles during a dramatic back-flip maneuver shortly before docking Wednesday.

This image of Endeavour's starboard wing was taken by the Expedition 27 crew during a survey of the approaching shuttle prior to docking with the International Space Station. As part of the survey and part of every mission's activities, Endeavour performed a rendezvous pitch maneuver, or back-flip, so that the shuttle could be photographed from a variety of angles. The image was photographed at a distance of about 600 feet.

Endeavour docked at the space station's forward port at 6:14 a.m. EDT Wednesday, May 18, 2011, after a flawless rendezvous.

A photo made from NASA video shows the Endeavour docked on the Harmony node of the International Space Station, Wednesday May 18, 2011, on the penultimate voyage of the space shuttle program.

The Endeavour astronauts float into the International Space Station about two hours after docking. Shuttle commander Mark Kelly shakes hands with station astronaut Ronald Garan.

With a backdrop of the Earth showing part of Italy, the aft section of the space shuttle Endeavour was photographed by an Expedition 27 crew member aboard the International Space Station, May 19, 2011. The vertical stabilizer, the orbital maneuvering system (OMS) pods and the lower part of the port wing are seen.

NASA astronaut Andrew Feustel participates in the mission's first extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 19-minute spacewalk, Feustel and astronaut Greg Chamitoff retrieved long-duration materials exposure experiments and installed another; installed a light on one of the station's rail line handcarts; made preparations for adding ammonia to a cooling loop; and installed an antenna for the External Wireless Communication system.

NASA astronaut Greg Chamitoff participates in the mission's first EVA, May 20, 2011.

The newly-installed Alpha Magnetic Spectrometer-2 (AMS) is visible at center left.

The docked space shuttle Endeavour is photographed by an STS-134 crew member on board the International Space Station during flight day six activities, May 21, 2011. Earth's horizon and the blackness of space provide the backdrop for the scene.

The docked space shuttle Endeavour is featured in this image photographed by an STS-134 crew member onboard the International Space Station during flight day six activities.

The thin line of Earth's atmosphere and the blackness of space provide the backdrop for the scene.

Intersecting the thin line of Earth's atmosphere, International Space Station solar array wings are featured in this image photographed by an STS-134 crew member while space shuttle Endeavour remains docked with the station.

Continuing a tradition for visiting shuttle commanders, NASA astronaut Scott Kelly, STS-134 commander, attaches a decal of his mission patch at the end of a growing collection of mission insignias displayed in the Unity node on board the International Space Station, May 21, 2011. Kelly is currently one of twelve astronauts and cosmonauts sharing work onboard the joint complex of space shuttle Endeavour and the ISS. Photo credit: NASA

Mission Specialists Drew Feustel (top) and Mike Fincke conduct the second spacewalk of the STS-134 mission, May 22, 2011.

The forward section of the space shuttle Endeavour is pictured with two components of the International Space Station (ISS) -- the Harmony node (left) and the European Space Agency's Columbus laboratory, May 25, 2011. Nine astronauts and cosmonauts continue to work inside the shirt-sleeve environment of the ISS and preparing for the final of four spacewalks on May 26.

With various components of the International Space Station in the view, NASA astronaut Andrew Feustel is pictured during the STS-134 mission's third space walk (and Feustel's third, as well), May 25, 2011. Astronauts Feustel and Michael Fincke (out of frame), both mission specialists, coordinated their shared activity with NASA astronaut Greg Chamitoff (out of frame), who stayed in communication with the pair and with Mission Control Center in Houston from the shirt sleeve environment inside the ISS.

With components of the International Space Station in the view, NASA astronauts Andrew Feustel (right) and Michael Fincke are pictured during the STS-134 mission's third spacewalk, May 25, 2011. The two mission specialists coordinated their shared activity with NASA astronaut Greg Chamitoff (out of frame), who stayed in communication with the pair and with Mission Control Center in Houston from the shirt sleeve environment inside the ISS.

With his Extravehicular Mobility Unit spacesuit backdropped against the blackness of space, NASA astronaut Andrew Feustel is pictured during the STS-134 mission's third spacewalk (Feustel's third for the mission and sixth overall in his career), May 25, 2011. Astronauts Feustel and Michael Fincke (out of frame), both mission specialists, coordinated their shared activity with NASA astronaut Greg Chamitoff (out of frame), who stayed in communication with the pair and with Mission Control Center in Houston from the shirt sleeve environment inside the ISS.

A portion of the International Space Station and the docked space shuttle Endeavour is featured in this image photographed by a spacewalker, using a fish-eye lens attached to an electronic still camera, during the STS-134 mission's fourth session of extravehicular activity (EVA), May 27, 2011.

A fish-eye lens attached to an electronic still camera was used to capture this image of NASA astronaut Michael Fincke (top center) during the mission's fourth session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station, May 27, 2011.

The aft section of the docked space shuttle Endeavour (STS-134) is featured in this image photographed by a crew member on the International Space Station, May 27, 2011.

A fish-eye lens attached to an electronic still camera was used to capture this image of NASA astronaut Greg Chamitoff during the mission's fourth session of extravehicular activity (EVA), May 27, 2011, as construction and maintenance continue on the International Space Station. During the seven-hour, 24-minute spacewalk, Chamitoff and astronaut Michael Fincke (visible in the reflections of Chamitoff's helmet visor), both STS-134 mission specialists, completed the primary objectives for the spacewalk, including stowing the 50-foot-long boom and adding a power and data grapple fixture to make it the Enhanced International Space Station Boom Assembly, available to extend the reach of the space station's robotic arm.

A bright sun, a portion of the International Space Station and Earth's horizon are featured in this image photographed by a spacewalker, using a fish-eye lens attached to an electronic still camera, during the STS-134 mission's fourth session of extravehicular activity (EVA), May 27, 2011.