Spaceships hull armor…solid?

[Agemegos]

Originally Posted by Anthony

I was more interested in whipple shields, where you would expect an initial impact to make a pretty large hole.

They don't make large holes. The impacts in the outer layers of Whipple shields make tiny holes, barely bigger than the impactors. I've seen photographs from experiments.

The reasons are that:

(1) The shields are deliberately made of material that is too weak and not rigid enough for destructive shockwaves to propagate through them. It evaporates locally but does not transmit much energy through itself.

(2) The momentum of the impactor is conserved in the debris, producing a cloud that continues into the space behind the first layer faster than it expands, i.e. a narrow jet rather than a spherical cloud. The explosion of the impactor and the bit of the first layer that it actually intersects effectively takes place behind the first layer of the shield, not within it, because of momentum.