Slide rule use in space

[4ster]

I thought this would be a good place to ask this question.

Over dinner last night conversation veered into 1960's spacecraft and their nav computers. I mentioned that backup was a slide rule and my very smart, slightly older, civil engineering friend snorted and said there was no way a slide had the precision necessary to navigate a space craft. Sitting next to me was another smart, but younger aeronautical engineer that went to school in the post slide rule era so he was not backing me up.

After dinner, at home I ran across a posting that on a Gemini mission a crew member calculated a burn time faster with his slide rule than with the onboard computer. The post was hearsay and not something that I would consider evidence. Did they even have an on board computer on Gemini?

We all acknowledge that slide rules were aboard Apollo, Gemini and possibly Mercury spacecraft. The question is were they precise enough to calculate burn rates for orbital navigation and re-entry?

I am just a forester and was never very good with a slide rule. Their use was sun-setting about the time that I was in classes where they were necessary. Calculators were becoming common place.