Countdown is halted on Obama's launch plan

Nasa abruptly called off space shuttle Endeavour's final launch yesterday because of a problem in a power unit.

Barack Obama and his family were planning to watch the take-off. It would have been the first time that a sitting president and his family witnessed a launch. Already at Cape Canaveral for the lauch was Gabrielle Giffords, the congresswoman seriously wounded in a gun attack in January and wife of the shuttle's commander.