Margaret Hamilton sitting on a mockup of the Apollo command module on display at MIT in 1969.
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File/AP
Margaret Hamilton, the computing pioneer whose software took NASA’s first astronauts to the moon, has died aged 90.
Hamilton’s death, from unspecified causes, on Sept. 30, was announced Wednesday by the Massachusetts Institute of Technology, where he worked from 1959 to the mid-1970s.
“To say that Margaret Hamilton was a pioneer, to say that she was ahead of her time, would be an understatement,” said Olivier de Weck, acting head of MIT’s Department of Aeronautics and Astronautics, in a statement. “She not only developed advanced code, but also led a team in using that nascent technology to develop one of the most complex systems humanity has ever achieved.”
Hamilton, who grew up in Indiana, earned a bachelor’s degree in mathematics with a minor in philosophy from Earlham College in 1958. She moved to Boston the following year (so her husband could earn his law degree) and accepted a job in the meteorology department at MIT, working with the professor who discovered chaos theory.
It was his first foray into software engineering. Hamilton then landed a programming job at another lab, working on the Semi-Automatic Ground Environment (SAGE) project, America’s first air defense system.
“He had a lot of foresight in thinking about the ways humans would use computers and creating reliable systems that could be used in even the most high-risk, life-or-death environments,” said Teasel Muir-Harmony, curator of the Apollo Collection at the Smithsonian National Air and Space Museum.
In 1961, MIT’s Instrumentation Laboratory won the NASA contract to develop software for the Apollo project. Hamilton saw an ad in a newspaper looking for people to develop software to “send a man to the moon” and applied. She was the first female programmer hired for the Apollo missions, starting with uncrewed flights and moving into onboard software.
By 1968, she had been promoted to deputy director in charge of the Command and Service Module team, leading a team of more than 100 engineers. Hamilton was in her early 30s, like many of her colleagues in the nascent field of software engineering, a term she is credited with coining.
Margaret Hamilton founded two software companies after leaving MIT. She is seen here at her home and office in Cambridge, Massachusetts, in 1986.
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Carol Francavilla/AP
“In this period that she worked, this is a completely new field and she really helped define it,” Muir-Harmony said. “Margaret Hamilton, like many of the people who worked on the Apollo program, really helped develop computing as we know it today.”
Hamilton made a great impression with his leadership and problem-solving skills. She often took her daughter, Lauren, then 4 years old, to the lab, resulting in an infamous “Lauren mistake.”
“His daughter overloaded a system during some kind of test. And he thought, ‘My God, this is something that could really happen in outer space. So I better keep this in mind,'” said Dean Robbins, an author who published a book about Hamilton in 2017. “So his daughter really played a role in his technical achievements.”
Hamilton was known for her focus on “defensive” programming, creating software that could anticipate and resolve errors on its own.
“Their goal was not just to build a system that would work when everything went right,” Muir-Harmony said. “It was about building a system that could continue to work when things went wrong.”
Perhaps the most famous example of this is the Apollo 11 mission in 1969. Just three minutes before the first humans landed on the Moon, onboard alarms went off, meaning a computer overload. Fortunately, Hamilton’s team had created a system that could close unnecessary background tasks at the time.
“Mission Control was able to recognize what was happening, trust the computer… to prioritize tasks, know that the astronauts could continue… with the first lunar landing,” Muir-Harmony said.
After leaving MIT, Hamilton founded two software engineering companies. She received the Presidential Medal of Freedom from Barack Obama in 2016, and the following year was immortalized in miniature as part of a “women of NASA” Lego set.
Hamilton is also the subject of a 1969 black-and-white photograph often circulated on social media, showing a young woman with long hair and glasses, smiling as she stands next to a huge stack of notebooks, filled with the code that sent humans to the moon.
President Barack Obama presents the Presidential Medal of Freedom to mathematician and computer scientist Margaret Hamilton in November 2016.
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Andrew Harnik/AP
But despite public recognition in his later years, Robbins said Hamilton was “not one to toot his own horn.” In fact, he initially rejected the idea of a biography, only agreeing because he thought it would be fun to read with his great-grandchildren. (He is survived by four great-grandchildren, two grandsons, his daughter, his son-in-law and three brothers.)
“She really got excited explaining what she had done, developing the software,” he recalled. “He was very excited to tell me all about the technical aspects of developing this. And he would send me pictures and the actual code he had written, and pictures of the primitive machinery they had had to use in the 1960s.”
The entire process was meticulous. Muir-Harmony explained that programs were stored in the Apollo guidance computer by hand-weaving copper wire through magnetized cores (“which basically looked like little donuts”). As a supervisor of that process, Hamilton earned the nickname “sane mother” in the laboratory.
Robbins struggled to simplify all that for his elementary school audience, until it hit him: Hamilton’s story was about problem solving. And in the process she broke barriers for women.
“There was no manual on how to use computers to take astronauts to the moon,” he said. “She had to come up with it on the fly and under tremendous pressure. And I think she was proud of it in her own modest way.”
Hamilton told MIT News in 2009 that, from his perspective, the software experience was “at least as exciting as the events surrounding the mission.”
“Looking back, we were the luckiest people in the world,” he said. “There was no choice but to be pioneers.”
