Teams scouring Texas and Louisiana for wreckage found a flight data recorder that typically activates 10 minutes before encountering the atmosphere and runs for up to two hours. Columbia broke up over east Texas, 16 minutes shy of its scheduled landing, on Feb. 1. Seven astronauts died in the accident.
The recorder was found intact on the ground about 7 miles from Hemphill, Texas, said Laura Brown, spokeswoman for the Columbia Accident Investigation Board.
"They suspect there may be heat damage," Brown said late Wednesday. "We just don't know what condition it might be in."
The recorder, which is unique to Columbia, stores information about the shuttle's flight systems during re-entry. If data can be retrieved, investigators should be able to refine their understanding of the aerodynamic forces affecting the damaged spaceship.
Columbia began shedding debris before it made landfall over California. Engineers believe a breach in the left wing allowed superheated air to blast inside the structure, triggering its breakup.
The recorder was to be taken to the Johnson Space Center in Houston for analysis.