Technical problem delays Endeavour's launch for at least 72 hours.
Just hours before the final flight of Shuttle Endeavour launch teams at Kennedy Space Center were forced to scrub the highly anticipated lift-off.
Hundreds of thousands had gathered along the coast, including wounded Congresswoman Gabrielle Giffords and President Obama.
For now, history will have to wait.
Less than four hours before lift-off, and as the astronauts were on their way to Pad 39-A, engineers discovered a problem with a heating thermostat on one of Endeavour's fuel lines.
The delay did not cancel at least one trip.
President Obama still traveled to Kennedy Space Center, touring the Orbiter Processing Facility with his family, then visiting privately with wounded Congresswoman Giffords.
Less than four months after she was shot at point blank range, the trip to the cape was her first outside of a hospital.
It has been a goal during her rehabilitation to be able to attend the launch.
Her husband Mark Kelly is the commander of the mission.
Just after the scrub Giffords' office Tweeted this short message:
"Bummed about the scrub!! But important to make sure everything on the shuttle is working properly."
That task now falls to the launch team, and engineers say it will take *at least* 72 hours to work through the problem.