Margaret Hamilton

Margaret Hamilton died on 30 September 2026 in a hospital in Cambridge, Massachusetts, at the age of 90. Her death was confirmed by her daughter, Lauren, and was announced on 7 October by MIT's Department of Aeronautics and Astronautics. No cause of death was made public.

She was survived by her daughter, Lauren Hamilton, her son-in-law, Richard Selesnick, two grandsons and four great-grandchildren. MIT said a memorial service would take place in Cambridge, Massachusetts, in the spring. Draper Laboratory, the successor to the MIT Instrumentation Laboratory, said her leadership had helped ensure that the Apollo astronauts landed safely on the Moon and returned home, and that her legacy would be honoured at Draper forever.

Margaret Elaine Heafield was born on 17 August 1936 in Paoli, Indiana, to Kenneth Heafield and Ruth Esther Heafield (née Partington). The family later moved to Michigan, and she graduated from Hancock High School in 1954. She had a sister, Kathryn.

She studied mathematics at the University of Michigan in 1955 before transferring to Earlham College, where her mother had been a student. She graduated in 1958 with a degree in mathematics and a minor in philosophy. She credited Florence Long, head of the mathematics department at Earlham, with encouraging her interest in abstract mathematics, and said her father, a poet, and her grandfather, a school headmaster, inspired her to study philosophy.

After briefly teaching high school mathematics and French in Indiana, Hamilton moved to Boston intending to study abstract mathematics at Brandeis University. In 1959 she instead began working for the meteorologist Edward Lorenz at MIT, writing weather prediction software on the LGP-30 and PDP-1 computers, work Lorenz later acknowledged in his research on chaos theory. From 1961 to 1963 she worked on the Semi-Automatic Ground Environment (SAGE) air defence project at MIT Lincoln Laboratory, and she also wrote software for a satellite tracking project at the Air Force Cambridge Research Laboratories.

In 1965 she joined the MIT Instrumentation Laboratory, which was developing the Apollo Guidance Computer for NASA. She was the first female programmer on the project and became Director of the Software Engineering Division, responsible for the team that wrote and tested all of the onboard flight software for the Apollo Command and Lunar Modules and for the Skylab space station. Her team built the error detection and recovery software, including restart routines and the priority displays she designed, which could interrupt the astronauts' normal displays to warn them of an emergency.

During the Apollo 11 landing in July 1969, several program alarms showed that the guidance computer was being asked to do more than it could handle. The software shed lower priority tasks and kept the ones needed for landing, and mission control gave the go to continue. Hamilton later wrote that without that recovery action she doubted Apollo 11 would have been the successful landing it was. She worked on the software for all six lunar landing missions between 1969 and 1972.

In 1976 she co-founded Higher Order Software with Saydean Zeldin, serving as chief executive until 1984. In 1986 she founded Hamilton Technologies in Cambridge, Massachusetts, which developed the Universal Systems Language and the 001 Tool Suite around her idea of development before the fact, designed to keep errors out of systems from the start. She published more than 130 papers, proceedings and reports.

She met her first husband, James Cox Hamilton, while at college, and they married on 15 June 1958. The couple moved to Boston, where their daughter, Lauren, was born in 1959. They divorced in 1967, and two years later she married Dan Lickly.

Hamilton is credited with coining the term software engineering, which she began using during the Apollo program to argue that building software deserved the same respect as other branches of engineering. Over time the term and the discipline gained that standing, and IEEE Software marked its 50th anniversary in 2018. Her emphasis on preventing errors rather than only testing for them shaped later thinking on reliable systems.

She received the Augusta Ada Lovelace Award from the Association for Women in Computing in 1986, the NASA Exceptional Space Act Award in 2003, the Presidential Medal of Freedom in 2016, the Computer History Museum Fellow Award in 2017, the Washington Award in 2019 and induction into the National Aviation Hall of Fame in 2022, along with honorary doctorates from the Polytechnic University of Catalonia and Bard College.

Her 1969 photograph beside the Apollo code listings became an emblem for women in computing. In 2017 she was one of the figures in the LEGO Women of NASA set, and in 2019 the mirrors of the Ivanpah Solar Power Facility were arranged into her image to mark the 50th anniversary of the Moon landing.