NASA officials said Monday night that they believe the gouge to the bottom of the space shuttle Endeavour is not severe enough to keep the spaceship from returning safely to Earth, but they want more time to consider whether the slightly damaged heat shield needs to be repaired in orbit.

Working from detailed photographs of the 3 1/2 -inch-by-2-inch indent on Endeavour’s thermal tiles, NASA officials will now create similarly damaged tiles to discover whether they can withstand the heat of re-entry. A repair decision is expected by Wednesday, but deputy shuttle program manager John Shannon said in Houston that the prognosis remains good.

“This is not a catastrophic loss-of-orbiter case at all,” he said. “This is a case where you want to do the prudent thing for the vehicle.”

Although the gouge is small, it pokes through the thermal tiles, which protect the shuttle during re-entry. Under the tiles is only a thin felt layer over the space shuttle’s aluminum frame.