Question The code that took America to the Moon

Now, I'm not a programmer, nor am I particularly interested in space travel and astronomy... But, I know a number of people around here are either one or both of those things... So I figured I'd share this article for those of ya who get into these sorts of things....

qz.com/726338/the-code-that-took-america...-1960s-time-capsule/

And one person built a working replica of the Apollo Guidance Computer. (Took him 4 years, though.) The instruction set and architecture are, by today's standard, quite strange, but it worked.

Apollo Guidance Computer

One of the moments I found particularly humorous in The Martian is when, in order to communicate with Watney using Pathfinder, they have to dig out the old communications array because the Pathfinder is so far out of date that none of their modern systems can communicate with it.

Um, as I remember, what they 'dug out' was the replica Pathfinder probe, not a 'communications array'. NASA deep space communication arrays are purpose built radio telescopes, and vary in size from 20 meters across to 70 meters across.

They dug out the replica probe so that they could use it to program and test instructions before they sent them to the real Pathfinder robot.

EDIT: Thinking about this, "Replica" is probably not the best word, "Developer Platform" is probably more accurate. It is the computers, software and duplicate hardware used by the scientists to write and debug the programs for the Pathfinder Probe that they dug out and used.

It's been a while since read the book. Poor word choice aside, they needed to dig up old equipment and engineers who had long since moved on to other projects in order to communicate effectively.

Needless to say, eagle-eyed watchers have raised several issues , many of which aren't entirely serious (e.g. "Extension pack for picking up Matt Damon", "Cannot locate astronaut ice cream"), while someone raised an issue which actually did occur in the flight (Error 1201 and 1202 if rendezvous radar is turned on) and another raised an issue which occurred on Apollo 13 (Check continuity on O2 cryogenic tanks before allowing stir ).

1201 and 1202 were overflows due to both the landing and rendezvous radars being on. Procedure was to switch off the rendezvous radar during descent; the program was never tested with both on. The alarms meant that the program executive missed a lower-priority task execution cycle due to too much input data. That's why the call from the backroom was essentially, "if it doesn't repeat, we're go on that 1201." Low priority computer tasks could be safely ignored because primary flight control tasks were working correctly. A continuous or highly-repetitive 1201 or 1202 would have meant serious trouble.

I could continue with a very lengthy discussions here, but I won't because a) I'd sound like a "know it all" (i really AM a rocket scientist), b) I'm very tired, and c) someone would argue and I don't feel like arguing.

The computer does not work in the "O" "F" "F" mode.

Valentine wrote: The computer does not work in the "O" "F" "F" mode.

Engineering concern closed. Testing confirms computer results perfectly replicate design requirements for "O" "F" "F" mode.

At least there were no Id10T errors reported. That could have been catastrophic.