Spaceships hull armor…solid?

[Agemegos]

Originally Posted by Anthony

What happens is that, by the time the penetrator has encountered total mass equal to its own, it will have turned into a spray expanding at around 60 degrees and the resulting plasma is moving at half speed.

If it collided isothermally with an equal mass in vacuum, yes, Confined into a channel by surrounding armour material that cannot accelerate laterally fast enough to get out of the way, and converting kinetic energy to heat rather yhan expansion, no. The jet of impactor and armour debris spreads out less than you figure; more of its energy is converted to heat than you figure, and less to the kinetic energy of expansion. The penetration is narrower and deeper than you figure, and the explosion is delayed.