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Women’s History Month: Margaret Hamilton, The First ‘Software Engineer’

Margaret Hamilton is a pioneering computer scientist who created the term ‘software engineer’ and was in charge of the software for the Apollo moon landing in 1969. Let’s delve into how she invented the modern concept of software, and ‘saved’ the moon landing. 

The Beginning

Hamilton was born on the 17th of August 1936, in Indiana, US. She was a lover of maths from an early age and at Earlham College, Indiana, she studied maths with a minor in philosophy. Whilst studying at Earlham College she met her husband, James Hamilton, and they married in the late 1950s once she graduated. In 1959, her husband was studying law at Harvard and to help support her family, now with a young daughter, Lauren, she took a job at MIT. Here, she learnt to write software that predicted the weather. A year later she was programming systems to locate enemy aircraft in the SAGE (Semi-Automatic Ground Environment) program. In the mid 1960s she saw a newspaper ad that MIT were, in her words, “looking for people to do programming and send man to the moon,” and she thought, “wow, i’ve got to go there.” Her original plan was to study for a degree in abstract maths at the graduate school at Bradeis University in Massachusetts. However, the U.S space program had won her over with the fact that she would be working on something that had never been done before, so she applied for the role. Her success at SAGE was evident, and she was the first programmer, and first woman, hired for the Apollo project at MIT. In 1965 she became the head of her own department, the MIT Instrumentation Laboratory (aka the Draper Laboratory). This department was dedicated to the writing and testing of software for the Apollo 11 computers. These were two 70 pound computers, one was aboard the command module ‘Columbia’, the other was aboard the lunar module ‘Eagle’.  

Apollo 11

The 20th of July, 1969, marks the date that the ‘Eagle’ was approaching the moon’s surface. As it did so, the computers started to flash with warning messages. Astronaut Neil Armstrong was faced with a “go” or “no-go” decision that he had to make in mere seconds. He looked to Mission Control for advice and a young Hamilton assured the mission director that they could safely ignore the error messages. The confidence in the software developed by Hamilton and her team was so great that the astronauts were told to proceed, with the director saying “Go, go ahead, free”. Not long after, this was followed by “the Eagle has landed”, the astronauts had safely landed on the moon. 

The achievement of Apollo 11 was a huge feat, especially at a time where computer technology was just in its beginnings. The astronauts had access to a mere 72 kilobytes of computer memory. To put that into perspective, today, a mobile phone carries almost a million times that storage space! There was also no screen interface, with programmers having to use paper punch cards to feed information to huge, room sized computers.

How They Coded

Once the code had been punched in, it would be sent to a Raytheon factory, where the employees would weave copper wires and magnetic cores into a long ‘rope’ of wire. The majority of these employees were women and had previously worked at textile mills. As you may know code is written in ones and zeros, in this application, the wire went through the magnetic core when it was a one and around the core when it was a zero. This then created the ‘rope’ that carried the software instructions and compensated for the Apollo computer’s limited memory. These women who did the weaving work were known as LOL, no, not laugh-out-loud, but ‘little old ladies’. Hamilton, thus, was called ‘rope mother’. 

The ‘Lauren’ Bug

Hamilton was a working mother and she would often take her young daughter, Lauren, with her to work, on nights and weekends. One day, her daughter was copying her mother and ‘playing astronaut’ and pressed a simulator button which made the system crash. Hamilton saw that this was a mistake that could easily be made by an astronaut. She addressed the situation and recommended that the software be adjusted. However, her idea was pushed away as she was told that “astronauts are trained never to make a mistake”. Of course, during the Apollo 8 moon orbit flight, astronaut Jim Lovell made exactly the same mistake. Luckily though, Hamilton preempted this and her team were able to correct the problem within a few hours. For future Apollo flights, this protective software was now built in to prevent this mistake from happening again. 

‘Software Engineering’

Hamilton was tired of people not taking her career field seriously and so popularised the term ‘software engineering’. She wanted people to know that it was a legitimate field that deserved more credit. She initially got teased for the term, but, one day in a meeting, one of the well respected hardware engineers spoke up and said that he agreed with her, that it should also be considered an engineering discipline. Since then, ‘software engineering’ has been a recognised term and the career field to this day provides highly sought after roles. 

Later Ventures

The work that Hamilton had done guided the remaining Apollo missions and also helped Skylab, which was the first US space station. By 1972 she left MIT to start her own company, named ‘Higher Order Software’. 14 years later, in 1989, she launched another company, ‘Hamilton Technologies’. In this venture she created the Universal Systems Language. This was a further step to make the process of designing systems more dependable. 


In 2003, NASA awarded Hamilton with the NASA Exceptional Space Act Award. This acknowledged her contributions to software development and also gave her the biggest financial prize ever that, until then, NASA had awarded to a single person, $37,200. 

Aged 80, on November 22nd 2016, Hamilton was awarded the Presidential Medal of Freedom by then President Barack Obama. She was awarded for her work on NASA’s Apollo Moon missions. Obama stated that “her example speaks of the American spirit of discovery that exists in every little girl and boy who know that somehow to look beyond the heavens is to look deep within ourselves…she symbolises that generation of unsung women who helped send humankind into space.”

In 2017, Lego paid tribute to Hamilton’s work by creating an action figure that showed her as a small figure with big hair and glasses, with her Apollo code stacking up taller than she was. The prototypes for these figures are now in the National Air and Space Museum in Washington. Usually, software engineers aren’t viewed as action figures, but Hamilton showed her heroism throughout her career. She says that she remembers “being fearless, even when experts say ‘no, this doesn’t make sense’ they didn’t believe it, noone did. It was something that we were dreaming of happening, but it became real.” When asked what advice she would give young women aspiring to a career in coding, she said “don’t let fear get in the way and don’t be afraid to say ‘I don’t know’ or ‘I don’t understand’, no question is a dumb question. And don’t always listen to the so-called experts.”


“Margaret Hamilton led the NASA software team that landed astronauts on the moon”. George, A. March 2019

“Margaret Hamilton: “They worried that the men might rebel. They didn’t.” Corbyn, Z. July 2019

“Her code got humans on the moon- and invented software itself”. McMillan, R. October 2015

“Margaret Hamilton: pioneering software engineer who saved the moon landing”. Loeffler, J. October 2021

“What to know about the scientist who invented the term ‘software engineering’. Cameron, L. 2019

  • Written by Mikita Maru, March 23 2022