Moon is probably Heinlein's most fully-realized vision before he got self-indulgent and more interested in exploring what it would feel like to be a woman in a threesome than what future societies would be like.
The mass drivers in the book were designed for shipment of canisters of lunar grain to be shipped to precise splashdown points on Earth. Aside from the slight implausibility of Moon-as-breadbox and shipping such low-value cargo, the canisters were launched at precise times, with precise velocities, with some hints that the trajectory could be tweaked a bit at the end of the launch tube. Along with the complete freedom to choose trajectories if time-of-flight doesn't matter, that's enough degrees of freedom to explain the assumed ability to target any point on Earth. In the book the lunar rebels target "demonstration" spots near cities and in harbors, and only do actual damage after an obdurate UN refuses to negotiate.
As for re-entry, a massive object with a well-designed ablative shield has a predictable trajectory in atmosphere. Variance of impact location is pretty small.
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timeasmymeasure
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Date: 2004-01-09 07:43 pm (UTC)The mass drivers in the book were designed for shipment of canisters of lunar grain to be shipped to precise splashdown points on Earth. Aside from the slight implausibility of Moon-as-breadbox and shipping such low-value cargo, the canisters were launched at precise times, with precise velocities, with some hints that the trajectory could be tweaked a bit at the end of the launch tube. Along with the complete freedom to choose trajectories if time-of-flight doesn't matter, that's enough degrees of freedom to explain the assumed ability to target any point on Earth. In the book the lunar rebels target "demonstration" spots near cities and in harbors, and only do actual damage after an obdurate UN refuses to negotiate.
As for re-entry, a massive object with a well-designed ablative shield has a predictable trajectory in atmosphere. Variance of impact location is pretty small.