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Original Apollo 11 Guidance Computer source code for command and lunar modules

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Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#31

Post by sehugg »

wim wrote: post #30

This is such an interesting peek into the engineering of these sort of systems with very constrained resources at the time. Like any random file you open contains little pragmatic design decisions like this https://github.com/chrislgarry/Apollo-11/blob/master/Comanch... # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15 # DAY INTERVAL…

The LM landing algorithm was also based on a polynomial, with "time-to-go" as the variable. Problems would occur if that variable went negative.

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#33

Post by jve »

luciana1u wrote: post #32

the code that landed humans on the moon has 72k stars on github and your startup's monorepo still can't pass CI on the first try

Not the same goals, risks, monetary budget, time budget.

If your goal was to absolutely prevent any errors and you would go great lengths to do it, you would.

Just look at any safety critical systems: medical, transportation. There has been some incidents, but some systems do work really well that are developed today.

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#35

Post by sthuck »

wim wrote: post #30

This is such an interesting peek into the engineering of these sort of systems with very constrained resources at the time. Like any random file you open contains little pragmatic design decisions like this https://github.com/chrislgarry/Apollo-11/blob/master/Comanch... # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15 # DAY INTERVAL…

And I'm scared to hardcode some negligible config value that will never change

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#39

Post by lloydatkinson »

wim wrote: post #30

This is such an interesting peek into the engineering of these sort of systems with very constrained resources at the time. Like any random file you open contains little pragmatic design decisions like this https://github.com/chrislgarry/Apollo-11/blob/master/Comanch... # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15 # DAY INTERVAL…

Given the constant launch delays how could they justify hard coding a 15 day window like this?

Re: Original Apollo 11 Guidance Computer source code for command and lunar modules

#40

Post by bragr »

lloydatkinson wrote: post #39
wim wrote: post #30

This is such an interesting peek into the engineering of these sort of systems with very constrained resources at the time. Like any random file you open contains little pragmatic design decisions like this https://github.com/chrislgarry/Apollo-11/blob/master/Comanch... # THE POSITION OF THE MOON IS STORED IN THE COMPUTER IN THE FORM OF # A NINTH DEGREE POLYNOMIAL APPROXIMATION WHICH IS VALID OVER A 15 # DAY INTERVAL…

Given the constant launch delays how could they justify hard coding a 15 day window like this?

It wasn't hardcoded. The exact mission parameters (mission clock, moon position, orbital parameters, etc) were uploaded by mission control the morning of the launch. From that point, they had 15 days. The longest Appolo mission was 12.5 days.
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