SPACE CENTER, Houston — Space shuttle Discovery escaped damage from the potentially deadly chunk of foam that broke off from the fuel tank during liftoff but may have been struck in the wing by a much smaller piece, NASA said Thursday.

Even if the small foam fragment did hit, engineers believe the impact caused no damage of concern, said deputy shuttle program manager Wayne Hale.

"This is the closest to a potential hit that we have out of all the data we've got," Hale said at an evening press conference. That's why it generated "a great deal of interest," he added.

Despite the latest development, officials said Discovery still looks safe to fly home in a week but stressed it will be another few days before the space agency can conclusively give the shuttle a clean bill of health.

The mostly welcome news came after Mission Control received stunningly detailed photographs of Discovery taken by the crew aboard the international space station. The shuttle executed an unprecedented backflip to bare its belly to the cameras before docking with the space station.

NASA wanted to make sure Discovery did not suffer the kind of mortal wound that brought down Columbia in 2003.

"Everything we know at this point in time, I don't see anything that would keep us from being able to re-enter," said Steve Poulos, manager of the orbiter project office.

On Wednesday, NASA suspended all further shuttle flights after learning that a big piece of foam insulation weighing just short of a pound came flying off Discovery's external fuel tank in an alarming repeat of the problem that doomed Columbia. It missed Discovery.

The small bit of foam that may have hit Discovery's right wing came off about 20 seconds after the big piece and was from the same general area, Hale said. None of the wing sensors detected anything unusual there, and a laser-tipped inspection boom also did not pick up any damage. Camera views during liftoff were inconclusive because the foam tumbled out of sight.

NASA already has run tests showing that if the foam did strike the wing, it would have exerted just one-tenth of the energy needed to cause worrisome damage, Hale said. "So we feel very good about this," he said, noting that "we're going to find the source of these problems and resolve them."

All that remains before NASA can clear Discovery and its seven astronauts for landing is an inspection Friday by a new laser-tipped boom that will provide 3-D views of scraped thermal tiles on the shuttle's belly. The 100-foot crane will be able to determine the depth of what looks to be surface-coating damage, said John Shannon, flight operations manager.