The lunar module is about to touch down. Alarms go off. Neil Armstrong and Buzz Aldrin see them. Back on Earth, Margaret Hamilton’s heart races. She wrote those alarms. Then she knows what they mean. The computer is dropping its least important jobs to keep flying, just as she built it to. And it’s telling the crew. Houston reads it the same way and says go. Hamilton died Sept. 30 at 90. MIT announced it Wednesday.
Robert Lee Hotz writes her life in the Journal. She was born in Paoli, Indiana, in 1936 and grew up in Michigan copper country. In 1959 she started on computers, running calculations for Edward Lorenz, the MIT weather scientist the paper credits with chaos theory. Then came a $27 billion air-defense system with a 250-ton computer. A coding mistake would crash it. Alarms went off all over the building, and the machine kept no record of why. So she bought a Polaroid and snapped the bad code before the screen lost it. Programmers rarely got to touch the mainframe, so her group sent the operators off to play Ping-Pong and ran it themselves. “It gave us such a feeling of power,” she said.
In 1965 she joined the Apollo flight-code effort at MIT’s Instrumentation Laboratory, now the Draper Laboratory. By Apollo 11 she managed the code for both the command module and the lunar lander. The paper calls the Apollo Guidance Computer the most advanced portable computer of its day, the first with a display the crew could talk to. Her piece was the alarm codes. The machine would never hide a problem from the crew. Years later she set Armstrong’s blood pressure against her own. “Neil’s blood pressure was 150. I felt mine was 200,” she said. No bug was ever found in that software on a crewed Apollo flight. The code was adapted for Skylab, the space shuttle and the first digital fly-by-wire aircraft.
Two companies and a Lego figure
She co-founded Higher Order Software and ran it from 1976 to 1984. In 1986, at about 50 by her birth year, she founded Hamilton Technologies in Cambridge, Massachusetts, and ran that too. NASA gave her a special award in 2003. President Barack Obama gave her the Presidential Medal of Freedom in 2016. In 2017 Lego made a Margaret Hamilton figure, and her daughter put it together for her. In 2018 Blue Origin, Jeff Bezos’s space company, flew the little figure to space and back. “It meant a lot to me,” she said. Her code sits in the Smithsonian’s National Air and Space Museum. She leaves her daughter, two grandsons and four great-grandchildren.
Our read
The planning point is about risk (Investments/Risk, IN04), with a behavior lesson inside it. Her software did two things under load. It knew in advance what to drop first. And it told the crew which kind of trouble this was. That second part is what let Mission Control say go. A household plan needs both. Decide now what gets cut first if income falls or markets drop. Vacations before tuition, the second car before the mortgage, whatever your order is. Write it down while nothing is wrong.
Then build the alarm. A plan that says in writing that a sharp drop is the expected kind of trouble is a plan you can keep flying. Without that line, every alarm feels like the end. There’s a career note too. She started her second company at about 50, by the paper’s dates. Second acts are real. We’d rather set the drop order with you in calm weather than in the descent.