Margaret Hamilton, Who Led Apollo Software Development, Dies at 90
Computer scientist Margaret Hamilton, who led the development of onboard flight software for NASA's Apollo program at MIT's Instrumentation Lab, has died aged 90. She helped establish software engineering as a distinct discipline.
Margaret Hamilton, an influential computer scientist best known for leading the software engineering team at MIT's Instrumentation Lab during NASA's Apollo program, died on September 30. She was 90.
Hamilton authored more than 130 publications and helped establish software engineering as a field in its own right. She worked at MIT from 1959 until the mid-1970s, then became a successful entrepreneur and chief executive. In 2016, President Barack Obama awarded her the Presidential Medal of Freedom.
The road to Apollo
Hamilton was born in 1936 in Paoli, Indiana. She earned a bachelor's degree in mathematics, with a minor in philosophy, from Earlham College in 1958. She moved to Boston in 1959 and began working in MIT's meteorology department on weather prediction software with professor Edward Lorenz. She later worked at MIT Lincoln Laboratory on SAGE, the first US air defense system.
In 1965 she applied to the Instrumentation Lab, which had won a NASA contract to build Apollo's onboard flight software. She became the project's first programmer at MIT and its first female programmer. By 1968 she was an assistant director, and more than 400 people were working on the software.
Defensive programming and Apollo 11
Hamilton's four-year-old daughter Lauren once accidentally triggered a pre-launch program, P01, during a simulated flight, crashing the simulator. Hamilton proposed a software fix, but it was rejected on the grounds that trained astronauts would not make such a mistake. During the Apollo 8 mission in 1968, Jim Lovell did exactly that, and navigation data vanished. The changes were adopted afterward.
During the Apollo 11 landing in July 1969, the onboard computer raised a 1202 alarm, indicating overload caused by a hardware switch fault. Hamilton's team had built priority-driven software that could drop unnecessary background tasks to focus on critical ones. Houston allowed the landing to go ahead.
Later career
Hamilton founded Higher Order Software in 1976 and, a decade later, Hamilton Technologies, whose main product is the Universal Systems Language. Her honors include a NASA Exceptional Space Act Award in 2003 and induction into the National Aviation Hall of Fame in 2022.
She is survived by her daughter, son-in-law, two grandsons and four great-grandchildren. A memorial service will be held in the spring in Cambridge, Massachusetts.
