Holistic engineering

A lesson on holistic engineering from NASA and Margaret Hamilton - circa 1969.

Excerpted from a Smithsonian article:

Over time, Hamilton began to view the whole mission as a system:
— “part is realized as software, part is peopleware, part is hardware.”

In a bid to make software more reliable, [Margaret] Hamilton sought to design Apollo’s software to be capable of dealing with unknown problems and flexible enough to interrupt one task to take on a more important one. In her search for new ways to debug a system, she realized that sound could serve as an error detector. Her program at SAGE, she noted, sounded like a seashore when it was running. Once, she was awakened by a colleague, who said that her program “no longer sounded like a seashore!” She rushed into work eager to find the problem and to start applying this new form of debugging to her work.

As a working mother, she took her young daughter to the MIT Instrumentation Laboratory with her at night and on weekends. One day, her daughter decided to “play astronaut” and pushed a simulator button that made the system crash. Hamilton realized immediately that the mistake was one that an astronaut could make, so she recommended adjusting the software to address it, but she was told: “Astronauts are trained never to make a mistake.”

During Apollo 8’s moon-orbiting flight, astronaut Jim Lovell made the exact same error that her young daughter had, and fortunately, Hamilton’s team was able to correct the problem within hours. But, for all future Apollo flights, protection was built into the software to make sure it never happened again. Over time, Hamilton began to view the whole mission as a system: “part is realized as software, part is peopleware, part is hardware.”

A lot has changed since the days of Margaret applying her genius to our craft: Faster CPUs, modern languages, AI, etc

But, none of that has altered the basic principle that has always been true:

Great engineering happens when engineers deeply understand and build for the entire picture.

(Check out this great interview for more on Margaret.)