"There was no time to be a beginner.... There was no choice but to be pioneers,” said computer science pioneer Margaret Hamilton, whose code was essential for multiple NASA missions.

In the 1960s, “Take Your Daughter To Work Day” did not exist. For some women, such a day may have entailed baking cookies and doing housework, but engineer Margaret Hamilton had a very different approach. Hamilton brought her daughter, Lauren, to the lab where she worked on the Apollo 11 manned moon landing mission.

“Mostly men were working there, and they had somebody at home to take care of their kids,” recalled Hamilton. “I had no choice.”

Lauren wanted to “play astronaut” like her mommy, and didn’t understand that she’d done anything wrong when she hit a button that selected the prelaunch sequence during a simulated flight, crashing the whole lunar module system.

Hamilton wasn’t angry; she was actually grateful. Lauren’s mistake uncovered a huge defect in the system. She realized that an astronaut could make the same error during flight and tried to warn NASA that they needed to prepare for that problem. 

“Astronauts are trained to never make a mistake,” they scoffed.

But five days into Apollo 8, the first manned moon-orbiting flight, astronaut Jim Lovell made the exact same error that Hamilton’s young daughter had and lost all navigation data needed to get back home. Mission Control was able to manually correct the problem, but that fix wasn’t enough for Hamilton. Between Apollo 8 and the moon landing Apollo 11 mission, Hamilton developed a troubleshooting program that instructed the computer system to recognize an error, ignore the task that it had been working on, and switch to the more important task of correcting errors during an emergency. These instructions would prove to be invaluable during future flights.

On July 20, 1969, everyone at Mission Control held their breath as the lunar module Eagle (with astronauts Neil Armstrong and Buzz Aldrin aboard) was only three minutes away from humanity’s first landing on the moon.

Suddenly, error messages and warnings flashed across every control room screen—the Eagle’s computer was quickly approaching overload and would not be able to perform landing functions. 

Because of faulty checklist training, the astronauts had set a radar hardware switch incorrectly. The computer system was being flooded with commands, requiring more power than the system could handle. With only seconds to spare, Mission Control had to decide whether they should abort the mission—dashing years of work and humanity’s dreams of one day travelling to another planet—or risk crashing the module onto the moon’s surface, killing all aboard.

Charlie Duke, the spacecraft communicator at Mission Control, decided to trust Hamilton’s new software to prioritize the landing task. The software worked perfectly. With only enough fuel left for 60 more seconds of flight, Neil Armstrong’s voice rang through the speakers: “The Eagle has landed.”

One small step had been taken by one man and a giant leap for mankind—all because of a woman. In fact, the flight codes worked on all Apollo missions on the first try, thanks to the creativity of a female engineer. 

Pioneers have “no second chance” at success

From the beginning, Hamilton and her team were in charge of writing and testing software for Apollo 11’s two 70-pound computers—one aboard the command module, Columbia, and one aboard the lunar module Eagle. Hamilton had to search for her own answers with no training manual or examples.

“There was no time to be a beginner…. There was no choice but to be pioneers,” she told MIT News.

Hamilton’s outside-the-box thinking created ingenious solutions to complex problems. Faced with limited memory space on those early computers, Hamilton wrote code in ones and zeros that was sent on to a factory—staffed by former textile mill workers who were mostly women—who wove magnetic cores and copper wires that were imprinted with the numbers, into long ropes. The wires went through the magnetic cores to represent a one and around the cores to represent a zero. This created a portable memory solution: a rope carrying all the software instructions; Hamilton became known as “Rope Mother.”

To inspire more respect for the type of computer programming and coding she and her team were doing, Hamilton invented the term “software engineering” and became a trailblazer in computer science.

However, she had never envisioned such work becoming her career.

Hamilton imagined she would become a math teacher but was inspired by Florence Long, a math professor at Indiana’s Earlham College and her father, who recommended pursuing philosophy (an interest he and his daughter had long shared). Integrating those two subjects provided a natural segue way into computer science and systems design.

Hamilton also met her future husband, James, while in college. She spent a year teaching high school, and later gave birth to their daughter, Lauren. While both were on their way to graduate school, Hamilton supported the family as James studied at Harvard Law School.

Meanwhile, she was hired as one of the first female programmers at the prestigious Massachusetts Institute of Technology (MIT). While working on a computer system that could predict weather systems and track their movements using simulators, Hamilton even overcame a pompous colleague’s attempt to confuse her by coding in Latin and Greek, then asking her to check his work. He was surprised when Hamilton made her corrections using those same languages. 

She planned to pursue her own advanced degree in mathematics when James graduated, but the universe had something else in store.

“They announced that they were looking for people to program a computer to send man to the moon and I thought, Oh wow! I’ve got to go there,” Hamilton said

NASA, the astronauts, and the people of Earth are very glad that she charted a pioneering path in science. 

A legacy of software success

Hamilton guided the remaining Apollo missions, helped with the first US Space Station, and started her own software companies. She created the Universal Systems Language, another step towards her dream of an ultra-reliable computer.

Her work was honored with the NASA Exceptional Space Act Award, and she even became an action figure as part of the “Women of NASA” LEGO Ideas Collection.

One of her proudest moments may have been in 2016, when President Barack Obama awarded Hamilton the Medal of Freedom, saying, “Her example speaks of the American spirit of discovery that exists in every little girl and little boy who know that somehow to look beyond the heavens is to look deep within ourselves.”

Margaret Hamilton made history, but she knew she was only one pioneer on the path that a new generation of young girls must follow. She needed to teach girls that they could break barriers.

She advised girls to “continue even when things appear to be impossible…to stand alone or to be different; and not to be afraid to be wrong or to make and admit mistakes, for only those who dare to fail greatly can ever achieve greatly.”

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