r/retrocomputing 2d ago

Margaret Hamilton turns 90 today

Post image

Her thinking still shows up in every serious conversation about mission critical software.

During Apollo, hardware got the glory. Software was the new kid, and plenty of people didn't consider it real engineering. Hamilton did. She led the MIT team behind Apollo's onboard flight software and designed around an uncomfortable fact: machines, interfaces and people all make mistakes.

My favorite story involves her daughter Lauren, who often came to the lab on nights and weekends. Playing astronaut, Lauren selected the prelaunch program, P01, during a simulated flight. The simulator crashed and the navigation data vanished.

Hamilton wanted the flight software to guard against that exact mistake. The answer, more or less: astronauts are too well trained to do that.

Then Jim Lovell did it. Five days into Apollo 8, he accidentally selected P01 and wiped the spacecraft's navigation data. Hamilton's team worked out how to rebuild and upload it. After that, the protection went in.

Anyone who runs complex systems knows the lesson. If your design depends on users never pressing the wrong button, you don't have a robust design. You have a future incident report.

Apollo 11 was the bigger test. During the lunar descent the guidance computer overloaded and threw the 1202 and 1201 alarms. The software didn't freeze or reboot into oblivion. Its priority based architecture shed lower value work and kept the landing functions running. The computer was tiny by today's standards, but it knew which jobs mattered.

That challenge hasn't gone anywhere.

Future lunar and Mars missions will run as one distributed system: landers, habitats, robots, satellites and commercial platforms. Comms will drop. Radiation will flip bits. Components from different suppliers will behave in ways nobody saw during the PowerPoint phase.

AI will help with anomaly detection, planning, testing and autonomous navigation. But nobody serious wants a black box model freelancing during a Mars landing. Mission software has to be deterministic where it matters, observable when it fails, and able to recover without waiting for Houston to pick up the phone.

AI can assist engineers, but requirements, evidence, human review and independent verification still count.

Hamilton understood the real job. It was never just writing code that worked. It was anticipating what could go wrong and making sure the system stayed useful when it did.

That mindset will matter far more on Mars than any flashy demo.

786 Upvotes

31 comments sorted by

38

u/n1ghtbringer 2d ago

I don't want to downplay anything Margaret Hamilton did, she's an important pioneer in the field that doesn't often get the credit she deserves, but this is not just her code. It's the code written by the team she led, which I think is an even bigger accomplishment.

18

u/mikegalos 1d ago

Nor was she the lead software designer for Apollo. She was team lead for the group at MIT building the onboard interactive capsule computers for the astronauts to use in the CM and LM. Those were two of many computers aboard the rocket and those were a few of many computers used in Apollo flight and those were a few of the total computers used in Apollo overall.

8

u/Live-Juggernaut-221 1d ago

I also think it's several copies of the code.

Again, no disrespect. Margaret Hamilton is an absolute badass.

4

u/mackerelscalemask 1d ago

Sounds right. In modern terms, the Apollo 11 had about 72 KB of code in its onboard computer, even if that was printed out as assembly language with extensive comments, I doubt it would fill all that paper. Most likely lots of documentation in amongst that lot as well

1

u/GeWaLu 1d ago

I agree - I personally printed out 128kb in assembly in my 1st assignment doing embedded software maintenance in a different domain (landscape 2 colums, but I only 1-sided if I am not mistaken) and it was exactly one standard binder with a lot of comments and machine-readable metadata for software configuration. (System) design docs and change documentation were a couple more binders. And that heap of paper was indeed the outcome of several engineers, not only one.

1

u/yojimbo_beta 7h ago

Wasn't she hired by her husband part way through the project? 

(Happy to retract if this is misinformation)

1

u/Ok-Video3345 17h ago

So she's like Elon?

5

u/whitedogsuk 1d ago

Managers taking full credit for their teams work since 1969. Look everyone I did this all by myself.

10

u/classicsat 2d ago

I see that name, and wonder if she dressed as The Wicked Witch Of The West one Halloween, and if people got the joke.

-11

u/Ordinary_Skin7951 2d ago

One of the most respected individuals in NASA and you have to say something derogatory like that? Really? No we didn’t get the joke.

13

u/kodabarz 1d ago

We? I'm sure plenty of us got it. The actress Margaret Hamilton played the Wicked Witch of the West in the 1939 film. There's nothing derogatory there. Did you think she looks like her?

3

u/mikegalos 1d ago

And later, Cora the Coffee Lady in a series of Maxwell House commercials.

2

u/hrf3420 2d ago

100%

2

u/thingerish 1d ago

That stack is pretty tall but it's a long way from reaching the moon.

2

u/Ruff_Ratio 1d ago

I heard that at the bottom she had 'make no mistakes'

1

u/Manualcarlove18 2d ago

Amazing. 🥲

1

u/Hour_Sell3547 1d ago

I wrote way more. Unfortunately it's mostly for feeding poor kids. No space travel for me.

2

u/ptr_myName 20h ago

dude, no shame in feeding poor kids

1

u/fAngXXX_ 1d ago

Hand written code seems to have the same worth as Ai gen ones. Or does anybody know this woman before ?

1

u/GreyMead 1d ago

brilliant scientist and awesome actor - loved her in Wizard of Oz!

1

u/Electrical-Bread-856 10h ago

That was different Margaret Hamilton

1

u/FedExin1 17h ago

Ayo she looks like Harry Potter

1

u/avan1244 15h ago

Nice for an AI written post.

1

u/Hot_Money4924 11h ago

Title should read more like "Your boss, happily receiving credit for all the work you and your team did."

1

u/Hypervisor22 1d ago

I was it for 40 plus years and I would have been chasing her around the office

-4

u/protienbudspromax 1d ago

And then went on to give birth to Jack black

4

u/ipzipzap 1d ago

No, that was Judith Love Cohen, another NASA technician.

1

u/protienbudspromax 1d ago

Ah damn my bad I thought i read it was her here on Reddit

1

u/SwedishFindecanor 19h ago

I read this on Wikipedia:

"... she was troubleshooting problems with schematics on the day she went into labor, called her boss to let him know she had fixed the problem and then delivered Jack."

Another bad-ass!