Margaret Hamilton, who coded Apollo's moon-landing software, dies at 90

Margaret Hamilton, a computer scientist whose work on NASA's Apollo program helped define software engineering as a discipline, died on September 30, 2026, at the age of 90. The Massachusetts Institute of Technology, where Hamilton worked for roughly two decades beginning in 1959, announced her death, according to CBS Boston and Gulf News. Neither outlet reported a specific cause or location of death.

Why she is being remembered now

Hamilton became MIT's first hired programmer for the Apollo project and the first woman in that role, according to Gulf News. By 1968 she had risen to assistant director of software engineering, overseeing a team of more than 400 developers working on the Command and Service Module and Lunar Module software, the outlet reported.

She is also widely remembered for a photograph showing her standing beside a printout of the code she had written for Apollo, an image often cited as a symbol of early software development, according to ITPro.

The 1201/1202 alarms during Apollo 11

During the final minutes of the Apollo 11 lunar descent on July 20, 1969, the guidance computer aboard the Lunar Module Eagle triggered program alarms known as 1202 and 1201 just as astronauts Neil Armstrong and Buzz Aldrin were roughly three minutes from touchdown, CBS Boston and ITPro reported. The alarms indicated the computer was overloaded with more tasks than it could process in real time.

According to ITPro, software Hamilton's team had built automatically prioritized mission-critical functions and suspended lower-priority background processes, allowing the computer to keep running the landing sequence instead of forcing an abort. CBS Boston reported that this error-detection design is credited with allowing the landing to proceed.

Coining 'software engineering'

Hamilton is credited with originating the term software engineering at a time when the field had no formal standing of its own, according to Wikipedia and remarks from MIT faculty reported by ITPro and Gulf News. MIT professor Olivier de Weck, interim head of the university's Department of Aeronautics and Astronautics, said that calling her merely a pioneer would understate her role, noting that she personally developed advanced code while leading a team that built one of the most complex systems ever attempted, and that her career was focused on preventing errors and handling what she called the unknown.

Later career and honors

After the Apollo program, Hamilton co-founded Higher Order Software in 1976 and later founded Hamilton Technologies in 1986, building a systems-modeling methodology called Universal Systems Language aimed at preventing software errors before they occur, according to Wikipedia and ITPro. Gulf News reported she published more than 130 papers over her career.

In 2016, President Barack Obama awarded Hamilton the Presidential Medal of Freedom, the United States' highest civilian honor. CBS Boston reported that Obama described her as a pioneer in computing whose software architecture continues to influence technology today. She had earlier received NASA's Exceptional Space Act Award in 2003, according to Wikipedia.

A memorial gathering is planned for spring in Cambridge, Massachusetts, CBS Boston reported.