We found an undocumented bug in the Apollo 11 guidance computer code • Hacker News Board

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#141

Post by MBCook » Tue, Apr 07, 2026, 3:52 PM UTC

throwaway27448 wrote: post #112

Aurornis wrote: post #61

Earlier quoted context omitted.

> It's not even clear if AI was used to find the bug The intro says “We used Claude and Allium”. Allium looks like a tool they’ve built for Claude. So the article is about how they used their AI tooling and workflow to find the bug.

The article does not explain anything about how they used AI—it just has some relation with the behavioral model a human seems to have written (and an AI does not seem necessary to use!)

Sure it does.

They used their AI tool to extract the rules for the Apollo guidance system based on the source code.

Then they used Claude to check if all paths followed those rules.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#142

Post by jvm___ » Tue, Apr 07, 2026, 3:53 PM UTC

kevin_thibedeau wrote: post #135

deepsun wrote: post #62

Earlier quoted context omitted.

And that's why it's harder (or easier?) to make the same landing again -- we taking way less chances. Today we know of way more failure modes than back then.

They sent people up in a tin can with the bare minimum computational power to manage navigation and control sequencing. It was barely safer than taking a barrel over Niagara Falls. We do have much more capable and reliable technology.

Buzz Aldrin (?) was quoted as recalling holding a pencil inside the capsule as they were out in space and thinking "that wall isn't very thick or strong, I could probably jam a pencil through it pretty easily..."

Death being a layer of aluminum away changes your mind.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#143

Post by jacquesm » Tue, Apr 07, 2026, 3:54 PM UTC

f1shy wrote: post #138

buredoranna wrote: post #73

Still my all time favorite snippet of code. TC BANKCALL # TEMPORARY, I HOPE HOPE HOPE CADR STOPRATE # TEMPORARY, I HOPE HOPE HOPE TC DOWNFLAG # PERMIT X-AXIS OVERRIDE https://github.com/chrislgarry/Apollo-11/blob/master/Luminar...

Cadr here has no relation with lisp cadr, right?

https://news.ycombinator.com/item?id=16008239

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#144

Post by jaggederest » Tue, Apr 07, 2026, 3:55 PM UTC

wat10000 wrote: post #114

thinkingtoilet wrote: post #109

Earlier quoted context omitted.

Starting from the first test pilots, a lot of people died for us to get to the point to launch that flight. So while no one died on the flight, lots of people died just getting us there. If I recall, in The Right Stuff, it's mentioned that those early test pilots had something like a 25% mortality rate.

The early jet age was pretty nuts. Check the Wikipedia page for a random fighter from the era and you'll see figures like, 1,300 built, 50 lost in combat, 1,100 lost in accidents. And that's operational aircraft. Test pilots were in even more danger.

You should go back even a little further, the USPS air mail service lost 31 of the first 40 pilots.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#145

Post by djmips » Tue, Apr 07, 2026, 3:55 PM UTC

I think it's interesting that they found what seems to be a real bug (should be independantly verified by experts). However I find their story mode, dramatization of how it could have happened to be poorly researched and fully in the realm of fiction. An elbow bumping a switch, the command module astronaut unable to handle the issue with only a faux nod to the fact that a reset would have cleared up the problem and it was part of their training. So it's really just building tension and storytelling to make the whole post more edgy. And yes, this is 100% AI written prose which makes it even more distasteful to me.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#146

Post by nraynaud » Tue, Apr 07, 2026, 4:06 PM UTC

_2fnr wrote: post #122

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I took it as the extracted spec was weird and they looked into it.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#147

Post by [deleted] » Tue, Apr 07, 2026, 4:10 PM UTC

chrisjj wrote: post #126

perching_aix wrote: post #80

Earlier quoted context omitted.

It's (what they're describing is) just reverse engineering. That's what reverse engineering is.

Fortunately reverse engineering too is in the dictionary - to help anyone mistaking it for spec generation.

[deleted]

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#148

Post by airstrike » Tue, Apr 07, 2026, 4:10 PM UTC

riverforest wrote: post #42

Software that ran on 4KB of memory and got humans to the moon still has undiscovered bugs in it. That says something about the complexity hiding in even the smallest codebases.

^ This is slop. Typical platitude that really means nothing.

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#149

Post by croemer » Tue, Apr 07, 2026, 4:16 PM UTC

josephg wrote: post #2

Super interesting. I wish this article wasn’t written by an LLM though. It feels soulless and plastic.

And it turns out at least the part about Rust and locks is plain wrong. What a surprise: https://news.ycombinator.com/reply?id=47676938&goto=item%3Fi...

Re: We found an undocumented bug in the Apollo 11 guidance computer code

#150

Post by retard4 » Tue, Apr 07, 2026, 4:23 PM UTC

djmips wrote: post #145

I think it's interesting that they found what seems to be a real bug (should be independantly verified by experts). However I find their story mode, dramatization of how it could have happened to be poorly researched and fully in the realm of fiction. An elbow bumping a switch, the command module astronaut unable to handle the issue with only a faux nod to the fact that a reset would have cleared up the problem and i…

[flagged]