CAPE CANAVERAL, Fla. -- Space shuttle Discovery began its creep to the launch pad yesterday after a brief delay caused by the discovery of a crack in the external fuel tank's foam insulation. NASA later said the crack was no reason for concern.
The flaw was discovered as the spacecraft was being readied for the first shuttle launch since Columbia fell to pieces two years ago, killing all seven astronauts aboard. The disaster was blamed on a chunk of foam that fell off the tank during liftoff and gashed one of the wings.
National Aeronautics and Space Administration spokeswoman Jessica Rye described yesterday's flaw as a hairline crack and said that after sending images of it to the tank's manufacturer in Louisiana, NASA concluded it did not need to make any repairs.
NASA later said the 1.5-inch crack was high up on the shuttle in a spot where, if foam flew off, it probably would not hit the vehicle. ''It's a very, very tiny crack. Very, very narrow . . . well within our experience base," said Mike Leinbach, shuttle launch director.
NASA then began moving Discovery from its assembly building to the launch pad, after a delay of at least two hours.
Because of Columbia's disintegration over Texas in 2003, the tank has been extensively redesigned for Discovery's flight. NASA plans a mid-May liftoff with a launch window from mid-May to June, a period dictated by the position of the international space station, the shuttle's destination.
The Discovery was being moved on a 5.5-million-pound transporter along a specially built road that is almost as wide as an eight-lane highway. The 4.2-mile journey to the pad was expected to take hours, because the transporter moves at 1 mile per hour.