HP-65 in Space-how powerful?

[Felix Gross]

The usefulness of the HP-65 is e.g. documented in the NASA publication "CSM Rendevouz Book" available on the HP Museum USB Stick (always highly recommended).

More relevant to the initial question might be a webpage dedicated to HP calculators in space. E.g. https://hpinspace.wordpress.com/category/hp-65/

There is plenty of documentation about the Apollo onboard computer available. I found this http://web.mit.edu/digitalapollo/ very interesting reading as it also deals with the general human - spacecraft interface (e.g. total automatic control vs. pilot control).

Given this, comparisons between e.g. the computational power of the different units can be made. But a mere "floating point operation per second" (or something similar) comparison might be not a useful measure as the questions to include something in a mission were complex. Certainly the HP-65 beat the Pickett Slide Rule N600-ES e.g. used on Apollo 13 and now on display in the National Air and Space Museum. But that needed no recharger which might have been a plus in particular on that mission.

Feiix