Houston ? Department of Defense officials scouring routine radar samples have discovered evidence of an object “in the vicinity” of the space shuttle Columbia as it settled into orbit during the second day of its mission, NASA officials said Saturday night.

According to the radar images, the object neared the Columbia, then appeared to pass by, officials said — and may have struck it. The data, which NASA was only beginning to analyze, could mark a pivotal turn in the exhaustive but thus-far frustrating investigation into the craft’s Feb. 1 disintegration over Texas.

Several former National Aeronautics and Space Administration officials said it could support the notion that the space shuttle was not the victim of a launch pad accident, as many have surmised, but was struck by some sort of space junk or a tiny meteorite. Some analysts believe an impact like that, even if it was so soft that it was not detected by the crew, Columbia’s computers or Mission Control in Houston, could have opened enough of a wound to ultimately destroy the craft.