My kids have a rather nice picture book about the first moon landing titled “One Giant Leap”. I find it to be a fairly accurate retelling of the events of Apollo 11 in a poetic style. However, one line from the book caught me a bit by surprise:

Collins presses hundreds of keystrokes to make the docking work.

Is this accurate? What was the command module pilot’s responsibility with the AGC for an Apollo rendezvous?

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    $\begingroup$ For reference, the Apollo 11 Owner's Workshop Manual says that it took "30-130 key presses ... to align the IMU, and over 10,000 ... to fly to the Moon and back". $\endgroup$
    – orome
    Commented Jul 22, 2019 at 20:38

1 Answer 1


It’s plausible. There’s a detailed description of the computer operations of the rendezvous process here: https://history.nasa.gov/afj/loressay.html

The process describes several different programs running on the CSM computer at different points; just activating a given program takes several keystrokes. Some of these programs are run as a backup in case there’s a problem with the LM computer; others are run to monitor the progress of the rendezvous.

To take one example:

To aid the CSM's tracking of the LM, the CMP runs program P76, LM Target Delta V. As input, the CMP gives P76 the key parameters of the LM's burn; the time of ignition and the expected velocity components in all three axis.

I think each one of those input values is around 5-6 keystrokes by itself.

As the process involves taking the CSM computer through at least P32, P76, P33, P35, P79, and selecting different data values to monitor, “hundreds of keystrokes” seems about right.

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    $\begingroup$ Yeah, I think your P76 example works out to 45 keystrokes: V37E76E, V25E, [+/- then 5 digits and Enter]x3, PRO, V21E, [another +/-, 5 digits, and Enter], PRO. $\endgroup$
    – hobbs
    Commented May 2, 2019 at 8:48

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