Margaret Hamilton, 1936 to 2026

October 8, 2026

Margaret Hamilton died on September 30, 2026, at the age of 90 in Cambridge, Massachusetts. She was the computer scientist who directed the Software Engineering Division at the MIT Instrumentation Laboratory, leading the development of the on-board flight software for NASA's Apollo Guidance Computer.[1]

She also coined the term "software engineering." She said she began using the term "to distinguish it from hardware and other kinds of engineering, yet treat each type of engineering as part of the overall systems engineering process."[2] At the time, programming was not recognized as an engineering discipline. She made it one.

The Apollo 11 Moment

Three minutes before the lunar lander reached the Moon's surface, the Apollo Guidance Computer triggered several alarm codes. The computer was overloaded with interrupts caused by incorrectly phased power supplied to the rendezvous radar. The alarms indicated "executive overflows," meaning the computer could not complete all its tasks in real time.[3]

Hamilton had prepared for exactly this situation years before. Her "priority display" innovation interrupted the astronauts' normal displays with priority alarms, giving them a go/no-go decision. Jack Garman, a NASA computer engineer in mission control, recognized the errors and shouted "Go, go!" The landing continued.[4]

Paul Curto, a senior technologist who nominated Hamilton for a NASA Space Act Award, called her work "the foundation for ultra-reliable software design."[5]

Before Apollo

Before Apollo, Hamilton worked for Edward Norton Lorenz at MIT, developing software for predicting weather on the LGP-30 and PDP-1 computers. Her work contributed to Lorenz's future publications on chaos theory.[6] She then worked on the SAGE Project at MIT Lincoln Lab, writing software for the AN/FSQ-7 computer used by the U.S. Air Force to search for possibly unfriendly aircraft.[7]

After Apollo

Hamilton founded two software companies: Higher Order Software in 1976 and Hamilton Technologies in 1986, both in Cambridge, Massachusetts. She published more than 130 papers, proceedings, and reports across about sixty projects and six major programs.[8]

On November 22, 2016, she received the Presidential Medal of Freedom from President Barack Obama for her work on the Apollo Moon missions.[9]

What She Left Us

The term "software engineering" is everywhere now. Every job posting, every university degree, every conference. She gave us the language to describe what programmers do as engineering, not just typing.

The Apollo Guidance Computer had 4 KB of RAM and 32 KB of ROM. The software Hamilton and her team wrote for it was robust enough to handle unexpected overload during the most critical three minutes in the history of human spaceflight. That is what good software looks like.[10]

She was 90 years old.

Footnotes

[1] Wikipedia: Margaret Hamilton
[2] Wikipedia: Software Engineering
[3] Wikipedia: Apollo Guidance Computer
[4] NASA: Apollo 11 Mission
[5] Wikipedia: Margaret Hamilton (NASA Space Act Award nomination)
[6] Wikipedia: Edward Norton Lorenz
[7] Wikipedia: SAGE Project
[8] Wikipedia: Margaret Hamilton (publications)
[9] Wikipedia: Presidential Medal of Freedom
[10] Wikipedia: Apollo Guidance Computer (specifications)