[Straight Vermonter]

What you are forgetting is that at the moment it broke off the was traveling at the same speed as the shuttle. Your equation should take into account not the speed of the shuttle but rather the relative speed of the shuttle to the foam.

[Falcon4.0]

Thanks, but I was using what I thought was the impact speed.
The foam would not carry much inertia and loose speed radiply. Anyway you slice it it's alot of force.