Margaret Hamilton, Apollo software pioneer who coined the term, dies at 90

Margaret Hamilton, the computer scientist who directed the team that wrote the onboard flight software for NASA's crewed Apollo moon missions, died on September 30, 2026, at a hospital in Cambridge, Massachusetts, according to MIT News and WBUR. She was 90.

Hamilton was born on August 17, 1936, in Paoli, Indiana, and grew up in Michigan's Upper Peninsula. She earned a bachelor's degree in mathematics, with a minor in philosophy, from Earlham College in 1958, according to MIT News.

Leading the Apollo software team

Hamilton joined the Massachusetts Institute of Technology in 1959, initially working on weather-prediction software before moving to MIT's Instrumentation Laboratory in the mid-1960s, where she led development of the onboard flight software for the Apollo Guidance Computer, according to MIT News.

By 1968 she was assistant director in charge of the command and service module software team, which grew to more than 400 people, MIT News reported.

Hamilton's team built what MIT News described as a "defensive" programming approach designed to anticipate and recover from errors rather than simply avoid them. That design proved critical minutes before the Apollo 11 lunar module touched down on July 20, 1969, when the guidance computer began flashing a 1202 alarm as it became overloaded with incoming data. According to MIT News, the priority-driven software Hamilton's team had built automatically shed lower-priority tasks and kept the critical landing functions running, allowing the mission to continue instead of aborting.

Coining "software engineering"

According to MIT News, Hamilton began using the term "software engineering" to describe her work and to argue that writing code deserved the same professional legitimacy as other engineering disciplines, at a time when colleagues reportedly found the phrase amusing. Olivier de Weck, an MIT professor who teaches about the Apollo program, told WBUR and phys.org that Hamilton worked as a software engineer at a time when the field was still in its infancy and had helped build one of the most complex systems achieved by humanity to that point.

Recognition and later career

After the Apollo era, Hamilton founded two software companies, Higher Order Software in 1976 and later Hamilton Technologies, where she developed what she called the Universal Systems Language for designing complex software systems, according to MIT News.

Hamilton received the Presidential Medal of Freedom in 2016, according to MIT News, WBUR and phys.org. MIT News also reported that she received a NASA Exceptional Space Act Award in 2003 and was inducted into the National Aviation Hall of Fame in 2022.

A widely circulated photograph of Hamilton standing beside stacks of printed Apollo code pages became a symbol associated with women's contributions to computing, according to MIT News and WBUR. In 2017 she was depicted in a Lego Minifigure as part of the "Women of NASA" set, according to WBUR and phys.org.

NASA Administrator Jared Isaacman said that Hamilton's work helped make humanity's first journeys to the moon possible, according to phys.org.

MIT News reported that Hamilton is survived by her daughter, Lauren Hamilton; son-in-law, Richard Selesnick; two grandsons; four great-grandchildren; and siblings John, David and Kathryn.

What is not yet known

None of the sources reviewed for this article reported a cause of death. MIT News reported that a memorial service is planned for spring in Cambridge, Massachusetts.