Shuttle wing lost sensors, maybe heat tiles

(CNN) -- As federal investigators begin to look into why the space shuttle Columbia broke apart, NASA officials said the left wing lost hydraulic sensors, lost tire pressure and then experienced intense heat before the shuttle broke up Saturday morning.

The same wing might have lost some heat resistant tiles at launch 16 days ago when struck by a stray piece insulation from a solid rocket booster.

"We don't think that the tiles were a problem. When we analyzed it 10 days we did not think that it was an issue," said NASA shuttle flight director Ron Dittemore.

"Is that the smoking gun? It's not. More evidence needs to be on the table," he told reporters.

Nevertheless, should a flag had been raised during the mission, shuttle astronauts would not have been able to conduct a spacewalk to inspect or repair the tile damage.

"We have no capability to repair it," he said.

The tiles protect the shuttle from the intense, friction-induced heat of atmospheric re-entry. However, a few have fallen off during other launches and Mission Control determined during this mission that there was no reason for concern this time.

Besides the tile issue, speculation on the cause includes extreme aerodynamic stresses on the 90-ton shuttle, which has been likened to a flying brick with wings as it plunges from orbit into the atmosphere, controlled not by engines but aerial flaps.

Should a shuttle steer in the wrong direction as it re-enters the atmosphere, going at many times the speed of sound, it could fly out of control and break apart due to the extreme stress, according to science experts.

Federal officials ruled out the possibility of terrorism, given that the shuttle was some 200,000 feet in altitude when it broke apart

In Washington, NASA Administrator Sean O'Keefe in a press conference Saturday said that the space agency will conduct an investigation into the disaster.

Moreover, an independent board will also investigate, including members from the U.S. Transportation Department and the Air Force and Navy. Five of the seven Columbia astronauts were from the two military branches.

After the shuttle Challenger exploded 17 years ago, the shuttle fleet was grounded for two years as it looked into the cause of the mishap and how to prevent it from happening it again.

In Texas, the Federal Emergency Management Agency was the lead agency in dealing with the disaster on the ground, where emergency personnel located smoldering pieces of debris.

The military responded as well, sending in search and rescue teams, helicopters and military police from Fort Hood, Texas, to help search for debris.

Emergency officials warned residents not to touch pieces of the shuttle for fear of exposure to toxic materials. The debris field is concentrated in east Texas but is thought to include Louisiana, Oklahoma and perhaps other states.'s Richard Stenger contributed to this report.