... given the thing was 20 years old I reckon could be more likely to be structural ("air" frame) failiure through stresses... But who knows.

How they are going to reconstruct the shuttle will be interesting, given that it fell 200,000 feet.
However, given the wonders they do with airplane disaster recovery - I am sure they will find something...

I assume they will have either black boxes or cockpit recorders too on the thing... Although I am sure that the "black boxes" will have taken some battering...

Bummer regardless...