|I haven't seen this discussed here, forgive me if it's a repeat.
I sent a mail recently to the editor at G2mil.com, asking about kinetic weapons for bunker busting. I had been thinking about this for a while, having seen references to similar ideas in fiction. I couldn't understand why it wasn't being done, as it seemed like pretty simple technology.
Take a tungsten or DU rod, say three meters long or so, put on some fins and actuators for guidance, and a GPS unit in the tail. Loft it up to low earth orbit, and when you want to make something go away, drop a big dart on them.
If we're talking a deep bunker target, the question wouldn't be whether it was destroyed, but rather how much was converted to plasma and how much was reduced to fine powder. Not to mention that you might strike oil in the process.
Someone with knowledge of the math could do the exact calculations, but I think it's safe to say that the KE and penetration would fall in the "Holy Jesus" category.
It really could be dirt-simple tech. You have the cost to loft it upstairs, and its carrier has to be able to project it onto a vector, but that's it.
Anyway, editor came back and surprised me by saying yeah, it's a good idea, and folks are already working on it. They call them "Rods From God". See:
One thing that concerns me about such a system, though, is that the potential level of destruction is pretty danged scary, and there's no fear of fallout or other nuclear contamination to put a brake the decision to use them.
Anyway, wondering what people think of the idea.