A military radar system shows indications that an object might have separated from the shuttle Columbia in orbit, prompting a review of telemetry by NASA flight controllers to look for signs of anything - including impact by high-velocity space debris
quoted from

http://spaceflightnow.com/shuttle/sts107/030208object/

I thought that any impact severe enough to damage the orbiter would be felt/heard by the crew and that they made no such report. The article also mentions several other causes all of which are benign.

[edit typo]

<font size=-1>[ This Message was edited by: Sleepy on 2003-02-09 08:53 ]</font>