The fragment includes a 2-foot piece of carbon-composite panel, a dense material that covered the leading edge of the wing, and a 1½-foot piece of the wing itself. Engineers are not yet certain where the piece fits.
It could be extremely important, given that the trouble apparently originated in the left wing during the final minutes before the Feb. 1 flight broke up above Texas, killing all seven astronauts aboard.
Barely a minute after liftoff on Jan. 16, a piece of insulating foam from Columbia's external fuel tank broke off and slammed into the ship's left wing. The impact by the flyaway foam — exonerated by NASA during the flight as to having caused any serious damage — remains a central part of the accident investigation. In the final minutes of flight, some sensors in the left wing and in the left wheel well showed unusual spikes in temperature.
After the wing fragment was found last Friday, NASA's deputy associate administrator for spaceflight, Michael Kostelnik, called it "a significant recovery."
NASA originally said the piece was found west of Fort Worth. On Monday, the agency said satellite coordinates indicated it had actually been found near Corsicana, 66 miles southeast of Fort Worth.
The condition of the wing fragment wasn't immediately disclosed. NASA was checking the carbon panel and the silica glass-fiber thermal tiles for evidence of burning, either from the intense heat of re-entry or from something else.
"That's something that the engineers would be looking for," Kostelnik said.
NASA said it also has found the cover of one of the two landing gear compartments, another potentially critical piece because a temperature surge inside the left wheel well was the first sign of trouble. But officials do not yet know whether it is from the right or left side of Columbia.
Another incident highlighted the confusion even among top NASA officials as to what wreckage is being found — and where.
Bill Readdy, NASA's top spaceflight official, told reporters in Washington that one of the shuttle's main computers had been found in a Texas field "apparently in fairly good condition."
He later said he was informed by a Johnson Space Center manager that it was an avionics box, not a general purpose computer.
"When he had a chance to look at it, sorry, wrong, not a general purpose computer," Readdy said. "That was our hope, maybe we were hoping too much."
An avionics box monitors and controls most of the systems on the shuttle. There are more than 300 of the boxes in the spacecraft.
NASA Administrator Sean O'Keefe said debris would be taken this week to Kennedy Space Center in Florida, where it will be cataloged and assembled.
Engineers there will reassemble as much of the shuttle as they can in a hangar. An independent board investigating the disaster will have offices in the hangar.
Kostelnik said engineers are still looking at high-resolution photographs of Columbia taken by a powerful Air Force telescope camera, but said "no engineering judgment" has been made on the images.
One photo, taken a minute or two before Columbia broke up, is drawing special interest. A dark gray streak can be seen trailing the left wing, and the leading edge of that wing appears to be jagged. Kostelnik said resolution on the photos was no better than what was released to the public Friday.
Kostelnik said the agency is also looking at data collected by weather and Federal Aviation Authority radar to determine whether debris or a weather phenomenon could have been factors in the accident.
The Columbia investigation board held a series of meetings Monday in an office near Johnson Space Center, as its pace picked up. The chairman, Harold German Jr. — a retired admiral who investigated the 2000 bombing of the USS Cole — said two to three teams of experts would analyze all the pictures and video taken of Columbia as it flew over California, Arizona, New Mexico and, finally, Texas.
Meanwhile, a law enforcement officer in eastern Texas is accused of stealing debris from the shuttle. Federal prosecutors in Lufkin, Texas are charging Robert Hagan with theft of government property.
Hagan is a Harrison County constable.
Prosecutors say he's accused of taking a piece of tile and other debris while helping with the recovery efforts.
Court documents say he displayed some of the items to another officer when he returned home to Marshall, Texas.
So far, three people have been charged with theft of government property related to looting of shuttle debris.
The other two suspects were arrested last week.
Authorities say there are as many as 20 other investigations into possible shuttle debris theft.