It's less fun when you realize that being able to drop any meaningful amount of material from space is equivalent to having a weapon of mass destruction.

(This is actually a constant thing in spaceflight, that comes up because of the scales involved. Similarly to that, any engine able to cut down interplanetary travel to reasonable lengths (days, weeks) will have energy output of a WMD, and could be used as such.)

Also the disruption brought by let huge objects falling through the sky will be devastating to atomsphere.

Clearly we'll work out how to deliver through the atmosphere.