The brilliant pebbles were supposed to be stationed in orbit. What I'm talking about is simply an upgrade of the current ground based missile defense. The immense capacity of the Starship makes this possible. It also completely reverses the old cost calculus of offsense-defense in the ICBM space: in the past you could simply counteract an attempt at a comprehensive missile defense system by building one thousand more ICBMs, and if that was not enough, two thousand or ten thousand. It was cheaper to add one more ICBM than to add the capability to stop it.

In the near future that will stop being the case. The ICBM has to have, after all, a nuke, and a nuke will never be very cheap. The kill vehicle is simply a block of steel, or some other metal. A maneuverable one, but still, a much cheaper piece of equipment than a nuclear warhead. By the way, the fancy term for the nuclear warhead is "reentry vehicle", and, as the name implies, it has to be build to withstand the tremendous shocks of reentering the atmosphere. Not so with a kill vehicle: if it needs to reenter the atmosphere it means it failed to do its job and it's not needed anymore.

Of course, Russia and China have seen the writing on the wall, and that's why they started looking for alternate ways of delivering nukes. I'm talking here about hypersonic, nuclear capable, weapons.

Regardless, my point is that in the near future, SpaceX will get some eye-popping contracts from the Pentagon, and specifically for missile defense reasons.