In 1969, 32-year-old Margaret Hamilton led the team that wrote the onboard software for Apollo 11. With just 72 KB of memory and punch-card programming, her code had to be flawless.It was. Minutes before touchdown, the Apollo Guidance Computer triggered overload alarms. Hamilton’s built-in error-detection and priority system instantly shed non-critical tasks, keeping the lunar module on course. Neil Armstrong and Buzz Aldrin landed safely because her software refused to fail.Hamilton didn’t just help put humans on the Moon—she coined the term “software engineering” and invented many of the resilient coding practices we still use today. A pioneering woman in STEM who literally wrote the code that changed history.