Margaret Hamilton, the computer scientist whose onboard flight software helped NASA land astronauts on the Moon in 1969, has died at the age of 90. The Massachusetts Institute of Technology (MIT), where she worked for some 15 years, announced that she died on 30 September.
Hamilton joined MIT in 1959 and stayed until the mid-1970s, eventually managing its Software Engineering Division. She had moved to Boston, Massachusetts, with her husband, who was studying law, and originally took the job to support him. Born in Indiana in 1936, she studied mathematics at the University of Michigan and Earlham College. At MIT she first worked on software for weather prediction and later on programs to detect enemy aircraft. At the time, computer science was not an established discipline, and programmers learned largely on the job. When MIT won a contract from NASA, the US space agency, to develop the Apollo flight software, she joined the effort. "I was the first programmer to join and the first woman they hired," she told the Guardian in 2019. She eventually led a team of around 100 engineers and is credited with coining the term "software engineering".
Her best-known contribution came minutes before Apollo 11 touched down on the lunar surface. An alarm sounded on the spacecraft's computer, signalling an overload, and for a moment it was unclear whether the landing would have to be aborted. Hamilton and her team had anticipated such a problem by designing priority-driven software that dropped background tasks and kept the most critical one, the landing, running. The mission continued, and astronauts Neil Armstrong and Buzz Aldrin landed safely. "The error detection and recovery mechanisms had come to the rescue," Hamilton later said.
She became widely recognised through a 1969 photograph showing her beside a stack of printed code as tall as she was. In 2016, then US President Barack Obama awarded her the Presidential Medal of Freedom, saying that "our astronauts didn't have much time, but thankfully they had Margaret Hamilton" and that she symbolised "that generation of unsung women who helped send humankind into space". From the 1970s she founded her own software companies, including Hamilton Technologies, still based in Massachusetts.
MIT said that calling her a pioneer, or ahead of her time, "would be a dramatic understatement", noting that she worked as a software engineer before the title was commonplace. Earlham College said her legacy would continue to inspire future generations. Looking back in a 2009 MIT interview, Hamilton said: "We were the luckiest people in the world; there was no choice but to be pioneers; no time to be beginners." She is survived by her daughter, a son-in-law, two grandsons and four great-grandchildren.