system
Given the following post, respond as if you're commenting on Reddit:
human
[The Moon is a Harsh Mistress] How much, if any long term damage would be done to Earth after Operation: Hard Rock?
gpt
"A maximum of instructive shrecklichkeit with minimum loss of life." 

Operation Hard Rock involved roughly fifty impacts, and maybe half were over the ocean. The lunar catapult used by the rebels fired a standard load - 100 tons of rock in a magnetic steel jacket impacting at 11 kilometers per second, each impact letting six gigajoules go. As Heinlein himself notes, this is roughly equal to a 2-kiloton nuke. 

50 x 2k = 1 megaton. So there are lots of demonstratively loud explosions near big cities, but very little lasting damage (aside from the craters at Cheyenne Mountain). Some cities took direct impacts, and there you'd see a lot of lingering health issues even with a relatively low loss of life. Lots of vaporized nasty stuff in the air, asbestos and plastic and all that. Local death rates will trend up. 

Lots of pretty sunsets (especially in the Midwest), and local weather disturbances (especially in coastal areas which just got a lot of boiling seawater thrown into the air), but nothing that will be remarkable in a month or two.

The most important feature of the war was the antiballistic defenses which blew up a number of the impactors in orbit. There's going to be one hell of a debris belt left behind, orbiting at random altitudes and trajectories.