In the book, the three lunar penal colonies won their independence from Earth by throwing rocks at various targets on the planet.
First thing I thought of.
L
Yep, if it was written it must be true. :-)
I never read ‘The Moon is a Harsh Mistress.’ As a youngster I read Heinlein’s ‘Starship Troopers’ and loved it from the very beginning, though it slowed down after the first few chapters. I tried to read some other Heinlein, and he could have some fascinating plot ideas, but too many of them seemed to eventually just devolve into sex orgies between the characters and I lost interest in Heinlein books after seeing this in more than one of his works.
Yup - there’s a NASA white paper on it from just a few years back.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110007073.pdf
It should also be mentioned that the Chinese have recently conceived an interest in setting up a lunar colony. With a mass driver return system. They aren’t interested in returning to the moon for any PR value, they’re going there with serious intent.
An electromagnetic rail gun (or Trebuchet) could easily chunk rocks at earth.
The Moon’s Gravity Well is so much smaller than the Earth’s.
Hitting a specific target is another matter, unless your rock has terminal guidance.
:-)
You do understand that the book is a work of FICTION
“Read The Moon is a Harsh Mistress by Robert Heinlein before you make fun of the idea.”
That’s the first thing that came to my mind as well!!!
The escape velocity of the moon is ~5300 mph. It would take a helluva catapult to hurl even something tiny that fast, much less something with enough mass to survive the heat of falling through the earth’s atmosphere @25,000 mph and make it all the way to the ground. If that meets your definition of “very little energy,” we need to have a review of what “very little” means.