Can't speak to the missiles, but objects in low earth orbit travel at around 7km/s relative to the earth. The benefit of this sort of task is in both cases the

Can't speak to the missiles, but objects in low earth orbit travel at around 7km/s relative to the earth. The benefit of this sort of task is in both cases the target object doesn't move of its own accord, so presumably if you can predict the path of the object with enough precision then it would work. Clearly we can pinpoint a 1m satellite, but no idea on the error bars for a 1m meteoroid.