Margaret Hamilton with the Apolo 11 code listings / NASA

Margaret Hamilton, the Engineer Who Took the Apollo to the Moon

7 min readDec 25, 2014

We interviewed this computer science pioneer after her photo with the Apollo 11 mission code conquered Twitter

JD (@nevesytrof) tweeted this photo of Margaret Hamilton a couple of weeks ago with great success among his followers. And he was not the only one who published the picture. The photo, taken in 1969, shows this mathematician and computer science pioneer beside the software listings that were essential for the Apollo XI mission — it was thanks to her that Neil Armstrong and Buzz Aldrin could take a walk on the Moon.

Three-Fingered Fox (that’s how he signs) explains in Medium that since the Manhattan Project, that developed the first atomic bomb, “mere programming” was in charge of women, as working with punchcards seemed “much like typing”. However and during the 60’s, “they were usually given requirements from the tech people, but often designed the approach and set up the calculations themselves,” as was the case with Hamilton and the Apollo missions she worked for.

As we can read in a Wired piece published last August, “the lunar landing was one of the first time that software was ever entrusted with such a mission-critical, real-time task. And the application development work for that feat was placed in the hands of Margaret Hamilton — who had taught herself to program and had risen to become director of the Software Engineering Division of the MIT Instrumentation Laboratory, which developed the computer under contract to NASA”.

Indeed, the article published in Medium explains that “many of the earliest and most pioneering programmers were women, learning hands-on to do things that had never been done before. We all know about Amazing Grace Hopper, who wrote the first compiler,” and also coined the term “debug”, after some of her colleagues discovered that one of the computers did not worked correctly because of a moth.

In 1986 Hamilton founded Hamilton Technologies. We decided to call. And when we reached her, she seemed understandably surprised by the fact that a Spanish newspaper phoned her because a 35 year-old picture of her was a hit in Twitter. “Twitter?” Yes, the social network… Like Facebook… “Oh, my generation does not use these social media.” Despite this logic surprise, Hamilton (78) accepted our interview request and asked us to send our questions by e-mail.

I guess it must be strange to become “internet famous” for this photo now and thanks to social networks. Do you like the feeling?

As long as people have good things to say!

You said that you do not use social networks, but do you like this interest in your work?

It is always great when people take interest in your work.

Was this picture taken during the Apollo project development? When was it taken and who took it?

Here is a description of the photo excerpted from an MIT Draper Lab document:

“Taken by the Draper Lab photographer in 1969 (during Apollo 11). Here, Margaret is shown standing beside listings of the software developed by the team she was in charge of, the LM and CM on-board flight software team”.

I guess coding is very different nowadays…

Yes and no. In fact, some things in this area have become more advanced, some are less advanced then before, and some are staying the same.

How was to work in a project such as the first landing on the Moon?

I worked on all of the Apollo manned missions and a couple of Apollo unmanned missions. Apollo 8 comes a close second, it not equal, to Apollo 11 for the most exciting, memorable moments on the Apollo project.

Margaret Hamilton working on the Apollo project / NASA

I read that the Apollo would not have been able to land without your software. What did your software do?

Are you referring, for example, to Apollo 11 and the 1201/1202 alarms during landing? Here is how the problem and solution were described in my Letter to the Editor “Computer Got Loaded” published in the March 1, 1971 issue of Datamation:

“Due to an error in the checklist manual, the rendezvous radar switch was placed in the wrong position. This caused it to send erroneous signals to the computer. The result was that the computer was being asked to perform all of its normal functions for landing while receiving an extra load of spurious data which used up 15% of its time. The computer (or rather the software in it) was smart enough to recognize that it was being asked to perform more tasks than it should be performing. It then sent out an alarm, which meant to the astronaut, “I’m overloaded with more tasks than I should be doing at this time and I’m going to keep only the more important tasks; i.e., the ones needed for landing.” …Actually, the computer was programmed to do more than recognize error conditions. A complete set of recovery programs was incorporated into the software. The software’s action, in this case, was to eliminate lower priority tasks and re-establish the more important ones…If the computer hadn’t recognized this problem and taken recovery action, I doubt if Apollo 11 would have been the successful moon landing it was.”

Did you coined the term “software engineering” during this time?

Software during the early days of this project was treated like a stepchild and not taken as seriously as other engineering disciplines, such as hardware engineering; and it was regarded as an art and as magic, not a science. I had always believed that both art and science were involved in its creation, but at that time most thought otherwise. Knowing this, I fought to bring the software legitimacy so that it (and those building it) would be given its due respect and thus I began to use the term “software engineering” to distinguish it from hardware and other kinds of engineering; yet, treat each type of engineering as part of the overall systems engineering process. When I first started using this phrase, it was considered to be quite amusing. It was an ongoing joke for a long time. They liked to kid me about my radical ideas. Software eventually and necessarily gained the same respect as any other discipline.

Do you think that the importance of your work in this project has been recognized enough?

Time will tell. Hopefully, the solutions resulting from lessons learned from this project will be adopted on a larger scale.

Was it difficult for a woman to be an engineer and a scientist in the 60’s? Has the situation changed nowadays?

It depends on who the woman was, who she worked for and what the culture was in a particular organization. In general, some things were more difficult then and some more difficult now. On hindsight, some of the things that were accepted back then, because we (men and woman) did not know any better, are not accepted now; and they often seem quaint and even astounding when looking back. We still do other things out of ignorance today, such as continuing to pay women lower salaries than men.

Were there more women working in computer science compared to other engineering branches? How did your colleagues treated you? Is it very different from today?

Women, if they were in the computer science field at that time, were more often than not relegated to lower positions.

In the case of the Apollo project my colleagues (mostly male) and I were friends and we worked side by side to solve challenging problems and meet critical deadlines. We concentrated on our work more than whether one was male or female. We were more likely to refer to someone as a “second floor person”, “a hardware guy”, “A DAP person”, “an operating system guru” or a “rope mother (where the rope mother could be a male or a female)”.

In what other NASA projects have you worked?

I worked on all the Apollo manned missions and a couple of Apollo unmanned missions. Also, I worked on Skylab on-board flight software and preliminary system software requirements for the Space Shuttle flight software, to name a few.

What do you like the most about your work?

The ongoing challenges and the creative people we work with.

In 1986 you founded your own company. Why did you take this step?

To accelerate the evolution of our technology and to introduce it to more users.

In what are you working right now?

Continuing to evolve USL and its automated lifecycle (the 001 tool suite) and put together a more automated deployment infrastructure

The article publised in Medium was linked in Reddit, where it has more than 200 comments. Redditor Laioren sums up the work of this computer science innovator: “Uh… So she invented or helped ‘pioneer’ like… everything? That’s pretty cool”. Dneronique answers: “… And she did it all with punch cards”.

(Verne explores the internet since September 2014. This is a website from the Spanish newspaper El País focused on viral content. This interview was written by Jaime Rubio Hancock).