April 29, 2011
Charles Dharapak photo

The Space Shuttle Endeavor is seen on the launch pad from a helicopter as President Barack Obama arrives at Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011.

Chris O'meara photo

STS-134 crew members, front row from left, pilot Greg Johnson, commander Mark Kelly, second row from left, mission specialists Roberto Vittori of Italy, and Mike Fincke, third row from left, Greg Chamitoff and Drew Fuestel, leave the Operations and Checkout Building for a trip to Launch Pad 39-A Friday, April 29, 2011, at Kennedy Space Center in Cape Canaveral, Fla. Today’s launch was scrubbed due to technical issues.

J Carter photo

Ruth Sabinsly, orginally from Denmark, reacts after the Space Shuttle Endeavor’s launch was scrubbed as she sat in a Titusville, Fla. park Friday, April 29 2011. She has seen every Endeavor launch. NASA abruptly called off space shuttle Endeavour’s final launch Friday because of a puzzling heater failure in a critical power unit, disappointing huge crowds converging on the area for the afternoon liftoff. on its final mission.

Charles Dharapak photo

President Barack Obama, first lady Michelle Obama, daughters Sasha and Malia, and Astronaut Janet Kavandi, walk under the landing gear from beneath the nose of Space Shuttle Atlantis as they visit Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011.

J Carter photo

JoAnna Gaut, protests the President’s Obama’s visit Titusville, Fla., Friday, April 29, 2011 for the shuttle launch. The launch of Space Shuttle Endeavour and its six crew members was delayed. NASA abruptly called off space shuttle Endeavour’s final launch Friday because of a puzzling heater failure in a critical power unit, disappointing huge crowds converging on the area for the afternoon liftoff. on its final mission.

Charles Dharapak photo

President Barack Obama and first lady Michelle Obama meet with Space Shuttle Endeavor commander Mark Kelly, right, husband of wounded Rep. Gabrielle Giffords, D-Ariz., and shuttle astronauts, after their launch was scrubbed, Friday, April 29, 2011, at Kennedy Space Center in Cape Canaveral, Fla.

Phelan Ebenhack photo

Jacob Lewis, 8, left, sister Hope, 3, second from left, brother Caleb, 1, and their mother, Joy Lewis, right, and grandfather, Ed Blankenship, second from right, all of Stafford, Va., walk past the Rocket Garden while leaving a launch viewing area, after the space shuttle Endeavour launch was scrubbed, at the Kennedy Space Center Visitor Complex in Cape Canaveral, Fla., Friday, April 29, 2011.

Charles Dharapak photo

President Barack Obama, first lady Michelle Obama, their daughters Sasha and Malia, and Astronaut Janet Kavandi, walk under the landing gear from beneath the nose of Space Shuttle Atlantis as they visit Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011.

Chris O'meara photo

Marine One carrying President Barack Obama and his family fly over space shuttle Endeavour on pad 39A at the Kennedy Space Center in Cape Canaveral, Fla. Friday April 29, 2011. Space shuttle Endeavour’s launch was postponed due to a technical problem. President Obama who was planning to view the launch, toured the facilities.

J. Ake photo

A security helicopter fly past the vehicle assembly building at the Kennedy Space Center before the scheduled launch of space shuttle Endeavour at Cape Canaveral, Fla., on Friday, April 29, 2011. NASA scrubbed the scheduled launch for technical problems.

Chris O'meara photo

Space shuttle Endeavour is seen on Pad 39A moments after launch was scrubbed because of technical problems at the Kennedy Space Center in Cape Canaveral, Fla., Friday, April 29, 2011.

Phelan Ebenhack photo

Edward James, left, son Nicholas, 7, second from left, and mother Sandy Stevens, of Atlanta, Ga., walk past mockups of the space shuttle and external tank while leaving a launch viewing area, after the space shuttle Endeavour launch was scrubbed, at the Kennedy Space Center Visitor Complex in Cape Canaveral, Fla., Friday, April 29, 2011.