Routine mission overshadowed by potentially serious gash

CAPE CANAVERAL, Fla. -- A routine shuttle mission, highlighted by a teacher's first spaceflight and space station construction, is now overshadowed by a troubling gash in Endeavour's thermal shield.

A detailed laser inspection on Sunday of the difficult-to-reach area on Endeavour's belly could send astronauts out to repair the 3-inch wound later in the week, although NASA said that prospect appeared less likely than it did a day earlier.

Engineers scrutinized images of the gouge Saturday, the result of a strike by fuel-tank foam insulation at launch.

NASA said late Saturday that the piece of foam came off a bracket on the tank, then bounced off a strut farther down on the tank and shot into Endeavour. The encouraging news was that the debris was not ice, which would have been denser and potentially more dangerous.