[Zavien Doombringer]

Imagine a 4oz lead ball (.50) flying at 900fps ripping your arm off, what 2.5 lbs at 1500mph would do to anything!

Can you say crater...

[the_doc]

It's not that simple. This was 2.5 pounds of low-density and readily-deformable material. This markedly reduces the damage potential.

(Potential for collision damage involves issues of size and shape and density and elasticity in addition to total mass and velocity.)

I have heard elsewhere on FR that NASA had previously done tests of foamed insulation hitting the shuttle at high speed and had concluded that it's not necessarily a problem. I haven't seen the data, one way or the other, but as a former engineer, I would urge FReepers to take a wait-and-see attitude.

[Shanty Shaker]

You are forgetting that the chunk of foam had a speed relative to the speed of the shuttle not equal to the speed of the shuttle.