I think you mean "rods from God" well thats one name anyway. Very convincing but very expensive to put a rod of that much mass into space...only high priority targets would be on the list.
These are not dropped from space, only high altitude. The energy of the gravity fall of say 50,000 feet, combined with the mass and very small aerodymanic cross section is all that is required to bring these silent darts to a very high speed with enormous kinetic energy at impact....