- Technology Marches On: Just a single example computerized aiming systems widespread in that universe are apparently unable to plot and predict the target's behavior, and are only good for generating a firing solution here and now, requiring the presence of a skilled operator who can subconsciously "feel" the target. This largely corresponds to how the naval radar-guided gunnery worked during WWIInote , and was already obsolete by the time the novel was published: in 1958 SAGE, the first computerized air defense system capable of automatically plotting and tracking the targets across the whole US, was starting to get online. Heinlein really didn't get computers at all.
- Probably less that he didn't understand computers and more that he loved to depict futures in which advanced mathematical ability was a common route to success, if not an absolute requirement for it. Heinlein loved to depict characters sweating math problems to solve problems in tracking and targeting, navigation, medicine, even psychology. The idea of inputting a destination into a GPS and then just doing whatever it told you to do to get there would probably have horrified him.
Trivia / Citizen of the Galaxy