That ball of ionized air is opaque to radar, making the rocket hard to detect. Or, so I read somewhere. I don't know at what speed a rocket has to be going, be

That ball of ionized air is opaque to radar, making the rocket hard to detect. Or, so I read somewhere. I don't know at what speed a rocket has to be going, before the kinetic impact of 200Kg of solid metal exceeds the energy of 200Kg of explosives.