[rs79bm]

Could this possibly have been terrorism? Surface to air tracking missile? or a reentry-trajectory just a fraction of a hundredth of a degree off, set by a "deep mole" in Houston?

The shuttle was traveling 12,500 mph at 200,000 ft. My scientific expertise tells me that this was a heat related problem, mainly because at this point in re-entry some of the shuttles components approach 3,000 degrees Fh. There has been talk of a panel on the outside of the shuttle that could have been damaged, or something internal that malfunctioned and started a chain reaction. NASA will study all of its telemetry and electronic data communications to give us a better idea.

[Jackie]

My scientific expertise tells me ...

Have you calculated how long it took for the first debris to reach earth's surface from 200,000 feet? I'd be interested.