1440 GMT (9:40 a.m. EST)
During a mission status news conference yesterday, Entry Flight Director Leroy Cain was asked about any possible damage to the shuttle's thermal tiles during launch. The tiles are what protect the shuttle during the fiery reentry into Earth's atmosphere.
Tracking video of launch shows what appears to be a piece of foam insulation from the shuttle's external tank falling away during ascent and hitting the shuttle's left wing near its leading edge.
But Cain said engineers "took a very thorough look at the situation with the tile on the left wing and we have no concerns whatsoever. We haven't changed anything with respect to our trajectory design. It will be a nominal, standard trajectory."
1436 GMT (9:36 a.m. EST)
NASA is asking that any persons finding debris should stay clear given the hazardous nature of the materials and alert local authorities.
1435 GMT (9:35 a.m. EST)
The last voice communications from the crew involved a tire pressure message. Communications were then garbled and static. Contact with the shuttle was lost at about 9 a.m. EST.
1429 GMT (9:29 a.m. EST)
Search and rescue forces are now being deployed, NASA says.
1427 GMT (9:27 a.m. EST)
NASA says the shuttle was about 200,000 feet up and traveling at 12,500 miles per hour when contact was lost.
From all the reports we're receiving, it is becoming clear that the shuttle broke apart over Texas.
1419 GMT (9:19 a.m. EST)
Contingency plans are in effect in Mission Control.
1416 GMT (9:16 a.m. EST)
This was the time of Columbia's landing. What we know is contact was lost with the shuttle at about 9 a.m. EST and a sighting by residents in Texas reported a debris cloud following the plasma trail as Columbia streaked overhead.
1415 GMT (9:15 a.m. EST)
The flight dynamics officer reports there is no tracking of the shuttle.
1414 GMT (9:14 a.m. EST)
Entry Flight Director Leroy Cain has instructed flight controllers to get out their contingency plan.
1410 GMT (9:10 a.m. EST)
NASA is still seeking tracking data. Communications with the shuttle were lost about 10 minutes ago.
1409 GMT (9:09 a.m. EST)
Still no contact with Columbia or crew.
1406 GMT (9:06 a.m. EST)
Mission Control waiting for C-band tracking data and UHF communications with Columbia through MILA. Houston lost communications with the shuttle a few minutes ago over Texas. We have gotten reports of debris in the sky.
1405 GMT (9:05 a.m. EST)
THERE HAS BEEN NO COMMUNICATIONS WITH THE SHUTTLE. Mission Controllers waiting for tracking data from the Merritt Island station.
1404 GMT (9:04 a.m. EST)
We're getting reports from Texas of debris behind the shuttle's plasma trail during reentery.
1401 GMT (9:01 a.m. EST)
Columbia is out of communications with flight controllers in Houston. Now 15 minutes from landing time.
1359 GMT (8:59 a.m. EST)
At an altitude of 40 miles, shuttle Columbia has entered Texas.