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.