A question on Space.SE; Is it possible to navigate space travel with no computer? got me looking for a list of works where Heinlein solely relied on a slide rule to calculate navigation in space.

I came up with The Rolling Stones but I am looking for a comprehensive list.

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    To close voters: list should be small enough since it's restricted to works by Heinlein.
    – SQB
    Commented Nov 16, 2018 at 14:59
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    @SQB I agree too -- every book Heinlein wrote would only be a list of 40-50 titles. An few of those had slide rules used for astrogation. Heinlein was an engineer, he was well aware of the precision limits of a slipstick.
    – Zeiss Ikon
    Commented Nov 16, 2018 at 16:42
  • I think I remember that there is a computer in The Rolling Stones, just as a side note--appears near the beginning (when they are buying the ship, overhauling it, or leaving Earth/moon area)--I think they mention it has a three lobe brain and runs each calculation three times, to check for errors. Commented Nov 16, 2018 at 19:40
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    It's not Heinlein, but the Apollo 13 movie showed liberal use of slide rules in Mission Control.
    – Blackwood
    Commented Nov 16, 2018 at 20:58

2 Answers 2


Rocket Ship Galileo made references to using a slide rule -- as well as mentioning how the limited precision meant you had to have a human pilot rather than being able to "cut a cam" for an autopilot to do the job.

I think I recall Space Cadet also showing slide rules in use for piloting -- and these are the only books of Heinlein's that I recall going "inside the cockpit" enough to show that kind of detail. Have Space Suit Will Travel showed slide rules in several important scenes, but the characters never actually used them.

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    Well, this doesn’t exactly count, but as I recall Starman Jones used books of log tables. Its similar at any rate.
    – Broklynite
    Commented Nov 16, 2018 at 14:59
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    The difference with books of tables (given the described size of the volumes) is at least 2-3 more digits precision vs. even a 14" metal slide rule (3.5 digits at very best, 2.5 if you're working in the 7-8-9 mantissa range).
    – Zeiss Ikon
    Commented Nov 16, 2018 at 15:05

In Destination Moon it is at least implied that a slide rule is being used to calculate the trajectory needed to arrive at the Moon. The relevant part of the story is:

“Huh? I wasted reaction mass, so we’re going too fast? That doesn’t make sense." Barnes hooked a foot into the legs of the stool to anchor himself, and did a rough run-through of the problem with slide rule and logarithm table. “Well, boil me in a bucket!" He added humbly, “Doc, I shouldn’t have asked to be skipper. I don’t know enough."

Corley’s worried features softened. “Don’t feel that way, Jim. Nobody knows enough — yet. God knows I’ve put in enough time on theory, but I went ahead and urged you to make the blunder."

“Doc, how important is this? The error is less than one percent. I’d guess that we would reach the Moon about an hour early.”

“And roughly you’d be wrong. Initial speed is critical, Jim; you know that!”

“How critical? When do we reach the Moon?”

Corley looked glumly at the pitiful tools he had with him—a twenty-inch log-log slide rule, seven place tables, a Nautical Almanac, and an office-type calculator which bore the relation to a “giant brain” that a firecracker does to an A-bomb. “I don’t know. I’ll have to put it up to Hastings.” He threw his pencil at the desk top; it bounced off and floated away. “The question is: do we get there at’all?”

In Starman Jones there is no explicit metion of a slide rule being used for astrogation, however there is an implicit reference to it:

There was little to take. Groping in the dark he found the rucksack he used for hunting hikes and stuffed into it his other shirt and his socks. He added Uncle Chet’s circular astrogation slide rule and the piece of volcanic glass his uncle had brought back for him from the Moon. His citizen’s identification card, his toothbrush, and his father’s razor—not that he needed that very often—about completed the plunder.

  • I don't think the slide rule was used for primary calculations, it was the people aboard the rocket trying to figure how badly off they were after overboosting by 1%, without having direct contact with ground computers. Computers were in routine use where a building-sized machine could be used by the time this movie was written/filmed.
    – Zeiss Ikon
    Commented Nov 16, 2018 at 18:20
  • A mechanical integrator would probably be more useful than a slide rule here. We are solving systems of differential equations, don't we? Commented Nov 16, 2018 at 23:26
  • @DavidTonhofer Those and their electronic upgrades might well be the "giant brains" Heinlein refers to in the passage quoted above.
    – Zeiss Ikon
    Commented Nov 17, 2018 at 20:05
  • @ZeissIkon Quite likely. I love these contraptions. While Bush's Analyzer of ~1930 is ridiculously called a "super mind" in this recolored promo, the US Navy is more realistic in 1953 about its mechanical analog computers: they are just gears in a box. Being forced to know the ins and outs of the machine breeds realism. Commented Nov 18, 2018 at 1:02
  • Here is an interesting answer on whether manual in-space computations are possible for Apollo ("no"). Commented Nov 18, 2018 at 1:11

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