Why user interfaces in space should be simple

On the Apollo 11 mission to the moon, the interface to the computer was simple. Known as the DSKY, (DiSplay and KeYboard), it was exactly that, a simple keyboard with 19 buttons and a display.

AGC_user_interface

The DSKY

Inputting instructions involved converting the English words to a verb-noun pair, which were subsequently input as numbers. The noun referred to a device, the verb indicated the action to be taken [1]. For example Verb 37 was “Change major mode to”, which was used to change programs. To input a number would require the following sequence:

VERB number NOUN number ENTR
apolloUI

List of nouns and verbs

So when Buzz Aldrin issued the command 1668, he was issuing the verb 16 meaning “monitor decimal” and the noun 68 meaning “RNG(+Z),TG(BRK),VI[.1NM.M:S..1 FPS]” [2]. The 68 returned “ground range to landing site”, “time to go in braking phase”, and “absolute value of velocity” [3].

It seems overly complex, but in reality it isn’t.

Want to try it yourself? See how usable the interface is through this simulator.

apolloUIdiag

[1] https://www.hq.nasa.gov/alsj/alsj-CSMdocs.html

[2] http://www.ibiblio.org/apollo/FabrizioPresentationPhotos/A17_VN_Checklist.png

[3] https://www.hq.nasa.gov/alsj/a15/a15LMDSKY.html

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