Margaret Hamilton, Apollo software pioneer, dies at 90

MIT confirmed that Margaret Hamilton, the computer scientist who led teams developing Apollo’s onboard flight software, died on Sept. 30. She was 90. Hired in 1965 as the first programmer on MIT’s Apollo project—and its first woman programmer—Hamilton later became assistant director overseeing the Command and Service Module software team. By 1968, more than 400 people were working on Apollo’s software, MIT reports. Her work became especially visible during Apollo 11’s descent to the Moon. The onboard computer raised a 1202 alarm after becoming overloaded. Hamilton’s team had designed priority-driven software that could discard less urgent tasks and keep mission-critical work running. Mission Control trusted the system and allowed the landing to continue. The software was a team effort, but Hamilton’s leadership helped establish the reliability practices behind it. A similar lesson had emerged during Apollo 8. After Hamilton’s young daughter accidentally started a pre-launch program in a flight simulator, Hamilton warned against the action and proposed a software safeguard. The change was initially rejected; when astronaut Jim Lovell later triggered the program in flight, navigation data disappeared. Hamilton’s team was called in, and the protection was added. The episode helped shape her focus on “defensive” software designed to anticipate human error. Hamilton later founded software companies and spent much of her career arguing that software engineering deserved recognition as a discipline in its own right. She received the Presidential Medal of Freedom in 2016. “There was no choice but to be pioneers,” she once said of the Apollo team. Sources: [MIT News](https://news.mit.edu/2026/margaret-hamilton-computing-pioneer-dies-1007) · [Associated Press](https://apnews.com/article/277117af951ae33daa84c62658580322). Image: MIT News, photos via the MIT Museum.