An independent panel will figure out the significance of an email warning by a NASA engineer days before the shuttle disintegrated in the earth's atmosphere.

But NASA administrator, Sean O'Keefe, insists that similar email warnings are not unusual. "Those are the kinds of dialogues and debates that go on every single time, during every single mission", he said.

Two days before the accident a researcher send an email saying that the shuttle's tiles might have been damaged after the shuttle was hit by debris during liftoff. He claimed that the shuttle's condition was "survivable but marginal".