[laverya]

Do you know what the difference is between an ICBM and a warhead predeployed in orbit?

The ICBM can hit anywhere (instead of just where the orbit track happens to pass), in less time (or at most the same time, since deorbiting takes around half an orbit) with a better mass fraction (since it doesn't have to reach orbit and then deorbit afterwards) while being more accurate (you know exactly where the launch platform is, while satellites are harder to locate) and less vulnerable (you can harden an ICBM silo far more effectively than a satellite).

Really, it's hard to think of something that satellite anti-ground weaponry does better.

[rocqua]

Detection?

There is a lot of icbm detection. Unplanned rocket launches could lead to global nuclear annihilation. What happens if something seems to deorbit above the US? How much early warning and procedure is there?

Especially if you want to deliver conventional munitions to a non-nuclear power, a system like this seems better than an ICBM.

[laverya]

Except that detectability is an advantage, in the doesn't-set-off-global-thermonuclear-war sense. If your nuclear (or command) assets can be removed at any time without enough warning to launch, that means you have to launch now before that happens.

If you want to hit something with a conventional warhead in a non-peer state without warning, why not use a stealthy cruise missile instead?

[rocqua]

Stealthy cruise missles need a much longer time than anything from space.

I am not advocating weapons in space btw. Just pointing out what the advantages are.