Columbia Investigation

It now appears a falling piece of insulation may have caused more damage to Columbia than mission control first suspected.

During takeoff, a chunk of insulation from a booster rocket struck the left wing of the shuttle.

And all the data now points to a failure on the left side before the vehicle started to break apart Saturday morning. The debris may have loosened or knocked off tiles that protect the shuttle from intense heat during re-entry to the atmosphere.

Shuttle program manager Ron Dittemore says it is not clear to him yet that they have evidence that points to the fact that the debris was the root cause. He says they are gaining some confidence that it was a thermal problem rather than a structural indicator.

Meanwhile, in east Texas, the search for the shuttle debris goes on. A piece of charred heat tile could perhaps be another important investigative lead.

NASA also confirms they continue to recover remains of the astronauts.

Many months of investigation lie ahead. Former navy admiral Harold Gehman will head one independent inquiry; he will be trying to find answers to a tragedy that has bound the space agency and the nation together in grief.