site banner

Small-Scale Question Sunday for February 12, 2023

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

Jump in the discussion.

No email address required.

This question is mostly aimed at @wlxd based on this comment but maybe someone else also knows the history. What was Margaret Hamilton's actual contribution to the Apollo guidance computer code?

She's famous now for being the "lead software engineer of the Apollo project," which seems like a stretch based on most biographical summaries available on the web. Nasa credits her as "leader of the team that developed the flight software for the agency's Apollo missions" which is consistent with "lead software engineer for the Apollo project" but could be disingenuous depending on her tenure and contributions on the team. But @wxld made a strong claim: "What is less commonly known is that she joined that team as the most junior member, and only became a lead after the code had already been written, and the actual leads (whose names, ironically, basically nobody knows today) have moved on to more important projects."

Thank you for asking this question, it forced me to compile the sources for easy future reference, but, more importantly, also caused me to learn a new fact about the history of Hamilton's involvement in the project, which fundamentally changed, for the second time, my understanding of her role (stay tuned until the end).

In any case, I cannot answer it as stated, because there is too little easily accessible data to say accurately what was her "actual" contribution, and in any case I'm not so interested in this topic to spend months digging through primary sources. From the more easily accessible ones you can, however, glean some of her actual contribution. These were certainly not trivial, given that you can find some sources from way before the recent craze that refer to her by her name. For example this report published in 1982, on the history of AGC by David Hoag, who was the head of the entire thing, names Hamilton as the lead of "a team of specialists", which has written "much of the detailed code of these programs". This seems to imply that she did led the software team, but other evidence makes it rather clear that while it is true that she did, in fact, lead that team, she did not lead it as it was actually writing the detailed code of these programs.

In short, I thus very much stand behind the statement in my quoted comment. I think the clearest evidence is coming from the horse's mouth:

I was a young kid, and I was hired by Dan Lickly over here (pointing to Dan).


Then, because I was still a beginner, I was assigned responsibility for what was thought to be the least important software to be developed for the next mission. I was the most of the beginners; I mean, I was the first junior person, on this next unmanned mission.


And I learned an awful lot from Dan [Lickly], who was a real guru in all of these areas. I was trying very hard to learn from him all of the things that he knew that I needed to use in order to be more successful at doing my job.


We began to grow, and eventually Dan [Lickly] put me in charge of the command module software. He had the courage to put me over that whole area, and I got very interested in management of software; again, integrating all of the glue. And when Dan [Lickly] left, Fred [Martin] then even had more courage and gave me the responsibility for the LM too, in addition to the command module flight software and now I was in charge of all of the on board flight software.

She was put in charge of the command module software after Apollo 8, which flew in December 1968, just six months before the moon landing. I'm not sure exactly when she was put in charge of LM, whether it was before or after moon landing. In any case, I think it is safe to assume that between December 1968 and March 1969, which is when Hamilton submitted the final Apollo 11 software, no new software has been written for either CSM or LM.

To me, the above paints rather clear picture: the actual software lead was the aforementioned Dan Lickly, who, when the project was complete, moved on, and gave up the position to his mentee, whose growth he guided, from the most junior team member to a senior lead. Indeed, Dan Lickly is described in these proceeding of the conference on the history of the Apollo Guidance Computer exactly as someone who "was in charge of a larger group of programmers that did programming for the AGC on the CSM and LEM". The whole program was led by Frederick Martin, whom Hamilton also mentions as the person making the decision to promote her. It is he whom Hoag describes, in the article linked above, among "the notable names", as the lead of COLOSSUS (CSM) software program.

Now, here comes the best part, which I only now realized as I was redoing this research, trying to find again the sources that originally prompted my comment you linked: Hamilton married Dan Lickly in 1969 before Apollo 11 (which flew in July). Think about it: Lickly literally promoted his own fiancee to the position he was leaving behind, and half a century later, not only we never hear about Dan Lickly (say his name to not forget), but we get fed the story of the leader of the team that wrote the software that sent the man to the moon, without ever hearing that she only received this position when the whole thing was already done from the guy she was sleeping with.

Wow, that is surprising!

Lickly literally promoted his own fiancee to the position he was leaving behind, and half a century later, not only we never hear about Dan Lickly (say his name to not forget)

Indeed, her Wikipedia article doesn't mention Lickly at all except as her spouse.

Thanks for such an informative post.