Why couldn't it be a missle? That is basically what a space shuttle is attached to. If we have rifles that can shoot from a mile away, rifles that can take out battle tanks.........it is very unrealistic to say that some country does not have a rocket to shoot that high and fast.
They came across the news minutes ago stating from the Pentagon that moments after the shuttle began to re-enter that one of the satelites that detect when a missle is launched detected a huge amount of heat similar to that of a missle launch.
That too is a bit ironic..............