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Apollo 11 Had a Hidden Hero: Software

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Re: Apollo 11 Had a Hidden Hero: Software

#51
post #26
post #13

I recently started listening to a fantastic podcast called 13 Minutes To The Moon[0] produced by the BBC. It’s a retelling of the last 13 minutes until the Apollo 11 lander touched down. Episode 2 talked about the software and the 1202 program code. They interviewed the Guidance controller who was only 26 at the time and talked about how the average age of the flight controllers was 27. I thought that was incredible,…

I wonder how much of the low age is because it was a relatively new organization at the time. As a counter example, NASA's current average age is 50+ in many organizations. It's a blessing and a curse. Aging organizations retain lots of organizational knowledge but also tend to exhibit a lot of stagnation/complacency.

Yes, the podcast attributed it to NASA being a new organization and there being nobody with experience in most of the jobs. There were aircraft engineers and a small number of rocket engineers before, but NASA needed vast numbers of new employees and for jobs like mission control that just didn't exist before.

Re: Apollo 11 Had a Hidden Hero: Software

#52
post #50

Neat story but is the software really hidden? I feel like I have heard this story many times. It was one of the many feats of the Apollo program, I don't think I would consider it hidden.

As a casual space program buff, I thought the same. But I think most people do not realize how sophisticated this early computer and software were, and how important to the mission. The article emphasizes the well-calculated trust that the engineers and astronauts put into this first computer-controlled spaceflight operation.

Re: Apollo 11 Had a Hidden Hero: Software

#53
If anyone wants to learn more about the Apollo Guidance Computer, this talk[1] from 34C3 will teach you everything you wanted to know and more.

The AGC had some really fascinating features for the time, including a cooperative multitasking system, interrupt driven IO, and even a virtual machine for doing linear algebra!

[1]https://youtu.be/xx7Lfh5SKUQ

Re: Apollo 11 Had a Hidden Hero: Software

#54

CuriousMarc's Apollo Guidance Computer (AGC) restoration is a must-watch: https://www.youtube.com/watch?v=2KSahAoOLdU&list=PL-_93BVApb...

I’ll second that. I particularly liked the part on home the memory worked

I'm amazed at the technical skill and knowledge he and his team has. Fabricating simulations, replacement parts, unpotting modules and repairing them, etc, etc, etc.

I thought the Xerox Alto restoration was amazing - this beats it handily.

Re: Apollo 11 Had a Hidden Hero: Software

#55
post #27

This contains more technical information behind the 1202 alarms [0]. It is an awesome read. [0] https://www.hq.nasa.gov/alsj/a11/a11.1201-pa.html

Relevant text:

So what was happening during Apollo 11, as I recall, was that repeated jobs to process rendezvous radar data (that of course were not really there) were scheduled because a misconfiguration of the radar switches. Thus, the core sets got filled up and a 1202 alarm was generated. The 1201 that came later in the landing was because the scheduling request that caused the actual overflow was one that had requested a VAC area.

Quite fascinating that these alarms automatically rebooted computer and picked up essential jobs exactly where they had left off.

Re: Apollo 11 Had a Hidden Hero: Software

#56
post #34

Best quote in the excellent article: “You can’t get a de­gree in how to fly to the moon,” says Dana Dens­more, who joined the lab in 1965 and be­came a con­trol su­per­vi-sor for the lu­nar-lan­der soft­ware. “You had to get peo­ple who know how to think, who are cre­ative and alert. It was all in-vented on the spot.”

She certainly sounds interesting.

https://en.wikipedia.org/wiki/Cell_16

Re: Apollo 11 Had a Hidden Hero: Software

#57
post #46
post #38

Earlier quoted context omitted.

There's not really any debate. The MAX ignored very basic controls lessons that were learned and institutionalized, as you say, over 50 years ago.

I agree that the 737-MAX wasn't a good example. My limited understanding in a broader sense (as opposed to the specific 737-MAX case) is there is still considerable debate on who should have ultimate control (human or software) of the aircraft when making critical decisions. I remember reading an article a while back that made it seem like Boeing and Airbus were on different sides of this spectrum in basic design phi…

It's like any good technical religious debate: both sides have good points and the ideal that they're both working toward is somewhere in the middle.

Airbus has backed off trying automate everything (starting with AF 296 in 1988) and, as this MCAS debacle has demonstrated, Boeing is happy to add serious automation. The days of the "pilot's plane" are long over. Now it's ever thinnner shades of gray.

Re: Apollo 11 Had a Hidden Hero: Software

#58

I've been listening to "13 minutes to the Moon" from the BBC recently. https://www.bbc.com/news/science-environment-48232627 One part jumped out at me as brilliant especially for the time: when the computer was overloaded with tasks during the decent, it switched off all non-essential extras like screen displays in order to free up processing power. After that it shed even more to focus on only plotting the landing!

A few weeks back they said it was due to the delta h discrepancy, and Buzz did nothing wrong. This week they were saying that it was down to the docking rendezvous system being turned on, which had not been done before.

I don't know if they came up with new information and forget to redo that episode.

The delta-h discrepancy was a mismatch between the actual height above the moon, and what the navigation system expected, I believe Mission Control took over that.

I feel like the programme murkied the waters.

Re: Apollo 11 Had a Hidden Hero: Software

#59
post #26

Earlier quoted context omitted.

I wonder how much of the low age is because it was a relatively new organization at the time. As a counter example, NASA's current average age is 50+ in many organizations. It's a blessing and a curse. Aging organizations retain lots of organizational knowledge but also tend to exhibit a lot of stagnation/complacency.

Yes, the podcast attributed it to NASA being a new organization and there being nobody with experience in most of the jobs. There were aircraft engineers and a small number of rocket engineers before, but NASA needed vast numbers of new employees and for jobs like mission control that just didn't exist before.

Some people were being hired withouth interviews it mentioned too it mentioned were there repercussions to this?

Quite a change from answering all these bloody mediaeval riddles

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