Spaceships hull armor…solid?

[Fred Brackin]

Originally Posted by Agemegos

The strength and hardness of the armour and impactor are irrelevant compared with the energies involved. The impactor behaves like the jet or penetrator formed by a HEAT warhead, except even more so, and it penetrates deeply. It produces a narrow channel of violently shocked and evaporated armour that indeed expands sideways, but does so slowly compared with the velocity of the initial impact, e.

I would only expect such behavior only at velocities below that needed for meteoric explosion. When the velocity of impact is enough to blow both the impactor and the outer layer of armor into a plasma that's even hotter than that of detonating high explosive it's going to expand like high explosive and the net momentum of armor and impactor will be seen only over the whole explosion.