Margaret Hamilton – the unsung hero of the historic Apollo mission

In 1969, just minutes before Apollo 11’s Eagle module landed on the surface of the Moon, a computer screen suddenly played an alarm, forcing NASA to consider whether to stop the historic mission. Fortunately, software engineer Margaret Hamilton foresaw what could happen, helping the control center make the right decisions. Moments later, Neal Armstrong successfully landed the Eagle module and went down in history as the first man to walk on the Moon.

Hamilton was only 32 years old when she led a team of programmers from the Massachusetts Institute of Technology (MIT) that designed the flight software for the Apollo 11 mission. Without her hard work and leadership, not only the mission could have been possible. failure that three Apollo astronauts may even have perished during the mission.

Who is Margaret Hamilton?

Margaret Hamilton was born on August 17, 1936 in the town of Paoli in the state of Indiana, the Midwest of the United States. Her family later moved to Michigan, and Hamilton attended the University of Michigan for a time. However, she soon transferred to Earlham College in Indiana, where she graduated with a bachelor’s degree in mathematics.

In 1959, Margaret Hamilton took a job at MIT as a programmer working with Edward Norton Lorenz, the father of chaos theory. At the time, Hamilton was 24 years old and her husband had just entered Harvard Law School. For the next three years, Hamilton helped the family write software and program the meteorological system.

A few years later, Hamilton applied to work on a major project: writing code to send a man to the Moon. She was accepted and became the first programmer to participate in the Apollo project. By 1965, Hamilton was leading a group of programmers at MIT’s Draper Lab.

Hamilton’s team was responsible for designing the flight software for the historic Apollo 11 mission. “I was intrigued by both that great idea and the fact that it had never been done before,” Hamilton said.

Margaret Hamilton featured in the Apollo project. She was not only a woman – which was unusual enough at the time – but also “a working mother”. When she goes to the lab at night and on weekends, she often brings her young daughter, Lauren.

The Code to Put Man on the Moon

Initially, NASA did not think the Apollo mission would require complex software. According to MIT professor David Mindell, software wasn’t even included in the schedule and it wasn’t included in the budget either.

It wasn’t long before NASA realized the mission would fail without the right software, and by 1968, more than 400 programmers were working on Margaret Hamilton’s software team. The team wrote and tested the software for two Apollo computers: one on the command module and the other on the landing module.

If disaster strikes and all eyes are on the Apollo mission, then responsibility could be pushed toward Hamilton. “I was always imagining headlines and if they were about a disaster that had already happened, I would be named,” Hamilton recalls.

In the 1960s, creating software programs for a space mission was not easy. Hamilton and her team wrote code by hand on sheets of paper, then used machines to punch holes in the paper cards, which were fed into a computer to read as instructions.

After checking their punch card codes on a Honeywell mainframe for any errors during the simulator landing, the codes were shipped to a nearby Raytheon factory. Here, skilled women thread the program’s 0s and 1s through the magnetic rings representing the program’s 1s and 0s: a copper wire through a loop means 1 , going around the ring means 0.

These women are all seasoned seamstresses. Their rope helps to create a hardwired code for the modules that are effectively indestructible.

Apollo’s two computers had to calculate the navigation equations from space, or the mission would end. Computers have about 72 kilobytes of memory – less than one millionth of the capacity of a modern cell phone. It can store 12,000 bits – representing 1s or 0s – in copper wire memory, but only 1,000 bits in its temporary working memory.

How did Margaret Hamilton’s daughter save the Apollo 11 mission?

One day, Lauren pressed a button on the simulator and crashed the system Hamilton was testing. With the push of a button before starting in flight, Lauren erased navigation data from the system’s memory. “I was like: God! This could happen by accident on a real mission,” recalls Hamilton.

Hamilton reported the problem to her supervisor and suggested changing the program, but NASA didn’t want her to write more code to fix the problem, because more code meant more bugs. Instead, they decided to train the astronauts to never make a mistake.

However, on the next mission (Apollo 8), astronaut Jim Lowell still made the same mistake. This proves that Hamilton was right and that more code needs to be written to correct the error in case something goes wrong.

Hamilton calls it the Lauren error. “This error devastated the system and required the mission to be reconfigured. In the end, NASA let me put the change program in,” the software engineer shared.

Program change helps to fix the problem

During the Apollo 11 mission, Margaret Hamilton focused on observing software her team designed to guide astronauts Neil Armstrong and Buzz Aldrin toward the lunar surface.

Just three minutes before landing, an unexpected heart-pounding message flashed across the screen, alerting the astronauts of an emergency, needing to make a decision to land or not to land. According to some documents, there was a radar switch that was in the wrong place, causing the computer to overload.

Fortunately, Hamilton had been preparing for this situation years in advance. Thanks to the error detection and recovery mechanisms written by Hamilton, the software restarted and focused on the highest priority task: landing the Eagle module on the lunar surface.

Jack Garman, a NASA computer engineer in charge of mission control, recognized the meaning of the errors displayed on the screen and immediately informed the astronauts to continue controlling the grounding module, according to NASA. MIT.

“The software not only notifies people that there is a hardware problem, but it also helps to fix it. Fortunately, the people at Mission Control trust our software.” Hamilton added. “It was a relief that the module landed successfully. The astronauts were all safe and the software was working perfectly.”

In 2016, then-US President Barack Obama awarded Hamilton the Presidential Medal of Freedom – one of America’s two highest honors – to Hamilton. “Our astronauts don’t have much time, but fortunately they have Margaret Hamilton,” Obama honors the great contribution of female software engineers in the historic mission of mankind.

Doan Duong (Follow All That’s Interesting)