How Dangerous was USA 193?

Article on just how dangerous USA 193 (the sat the Navy shot down) was.

What made US 193 so singularly dangerous was its toxic fuel payload. "If it had just been hardware, we would never have considered these extraordinary measures," says Chilton. The presence of the toxic chemical, in a tank that was completely full because the payload had failed immediately after launch, was the unusual driving factor, Johnson concurs.

A graphic illustration of the nightmare scenario preoccupying Johnson and Chilton occurred in October 2004, when an off-course Chinese spy satellite's film canister smashed through the roof of a four-story apartment building in the village of Penglai in southwest Sichuan. But with USA 193, could the hydrazine have actually reached the surface in a sufficient concentration to hurt anyone? Wouldn't the tank be consumed by the heat of atmospheric entry and disintegrate high above Earth? Here, much press commentary was led astray by a popular misconception.

There is a widespread notion that meteorites falling to Earth arrive red hot, sometimes releasing superheated fumes or setting brush fires, as a result of the tremendous heating during their passage through the atmosphere. But this is untrue. Small meteorites actually fall to the ground cold, and under humid conditions they can even briefly form frost on their surfaces. Though a thin outer layer is briefly exposed to very hot air, for most of the descent that air is thinner than the purest vacuum inside thermal-shielding thermos bottles.