Computer Code for NASA’s Apollo Guidance System

Posted on June 13, 2015  Comments (4)

photo of Margaret Hamilton, NASA

Margaret Hamilton, NASA. Standing next to a printout of the source code she and her team wrote for the Apollo guidance computer that made the moon landings possible.

Meet Margaret Hamilton, the badass ’60s programmer who saved the moon landing

The software for the guidance computer was written by a team at the MIT Instrumentation Laboratory (now the Draper Laboratory), headed up by Margaret Hamilton.

The guidance computer used something known as “core rope memory“: wires were roped through metal cores in a particular way to store code in binary. “If the wire goes through the core, it represents a one,” Hamilton explained in the documentary Moon Machines. “And around the core it represents a zero.” The programs were woven together by hand in factories. And because the factory workers were mostly women, core rope memory became known by engineers as “LOL memory,” LOL standing for “little old lady.”

Hamilton is now 78 and runs Hamilton Technologies, the Cambridge, Massachusetts-based company she founded in 1986. She’s lived to see “software engineering” — a term she coined — grow from a relative backwater in computing into a prestigious profession.

In the early days, women were often assigned software tasks because software just wasn’t viewed as very important. “It’s not that managers of yore respected women more than they do now,” Rose Eveleth writes in a great piece on early women programmers for Smithsonian magazine. “They simply saw computer programming as an easy job. It was like typing or filing to them and the development of software was less important than the development of hardware. So women wrote software, programmed and even told their male colleagues how to make the hardware better.”

My aunt was one of those early software engineers. She wrote a chapter for a book, Programming the IBM 360, in the 1960s. My uncle was one of the first employees at NASA and rose to be one of the senior administrators there over his career.

It is great when society is able to capture the value individuals are capable of providing. We need to make sure we allow everyone opportunities to contribute. We do well in many ways but we also do lose from discrimination and also just making it uncomfortable for people to contribute in certain roles when we need not do so.

We have accomplished great things with software in the last 40 years. We could have accomplished more if we had done a better job of allowing women to contribute to the efforts in this field.

Related: The Eagle Has LandedBarbara Liskov wins Turing AwardGreat Self Portrait by Astronaut with Earth Reflected in His Visor

4 Responses to “Computer Code for NASA’s Apollo Guidance System”

  1. Anonymous
    July 7th, 2015 @ 3:37 pm

    It is great when society is able to capture the value individuals are capable of providing. We need to make sure we allow everyone opportunities to contribute. We do well in many ways but we also do lose from discrimination and also just making it uncomfortable for people to contribute in certain roles when we need not do so.

  2. liliy
    August 29th, 2015 @ 11:04 am

    This girl is just clever, has done a great job with the code, it is a pity that women programmers a little, they are more diligent, thank you for a great article

  3. Abu Shahid
    November 8th, 2015 @ 9:55 am

    It is great when society is able to capture the value individuals are capable of providing. We need to make sure we allow everyone opportunities to contribute

  4. Sarah
    February 19th, 2016 @ 12:45 am

    Great XD:) good job keep it.

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