You have a tungsten rod held in a clamp on a satellite in a nominally stable orbit. Releasing the clamp just means the tungsten rod is now in essentially the same nominally stable orbit as the satellite.
To deorbit it, you need to meaningfully change its velocity. As tungsten is very dense, that takes a lot of fuel. The more fuel that is used, the sooner the rod will hit the ground and the higher the angle.
Simply dropping it means you have to wait months or years for the orbit to naturally decay, a lot of energy will be lost to atmospheric friction, and there is little control over the impact point. Not exactly what you want in your WMD.
Wouldn’t it be easy to account for the forwards momentum and just lead on the shot?
The issue isn’t forwards, it is down.
You have a tungsten rod held in a clamp on a satellite in a nominally stable orbit. Releasing the clamp just means the tungsten rod is now in essentially the same nominally stable orbit as the satellite.
To deorbit it, you need to meaningfully change its velocity. As tungsten is very dense, that takes a lot of fuel. The more fuel that is used, the sooner the rod will hit the ground and the higher the angle.
Simply dropping it means you have to wait months or years for the orbit to naturally decay, a lot of energy will be lost to atmospheric friction, and there is little control over the impact point. Not exactly what you want in your WMD.