NASA’s Human Computers

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Podcast Transcript

Today computers are ubiquitous. You are listening to this podcast right now on some sort of computing device. 

However, before computers were machines, the name computer was given to people. Computers were people who computed. 

In fact, in the early days of NASA, the space program relied upon these human computers to do most of their calculations, most of whom were women. 

Learn more about NASA’s human computers and the role they played in the development of spaceflight on this episode of Everything Everywhere Daily.


The first use of the term “computer” dates back to the early 17th century. The first known written reference to the word computer was actually in 1613. 

A computer was nothing more than a person who computes, in the same way, that a baker is someone who bakes and a cleaner is someone who cleans.

The first computers were primarily tasked with calculating the orbits of the planets. Many mathematicians during the Renaissance would call themselves computers as frequently as they would mathematicians. 

Being a computer was often an introductory position that someone would take before becoming a full-blown scientist. 

Computers helped calculate the position of Halley’s Comet and were later used in the late 18th and early 19th centuries by the British Navy to determine navigational tables for ships. 

At this point, the job of computer was primarily reserved for men. There were only a few women who were employed as computers at this time. Women like Mary Edwards, who was employed by the British Board of  Longitude.

When the Americans created their own navigational tables, one of their best computers was a woman by the name of Maria Mitchell, who discovered a comet which was named “Miss Mitchell’s Comet.”

The latter half of the 19th century saw a shift in the hiring of computers. Whereas women were mostly excluded from being computers previously, now they were actively sought out. 

Computing wasn’t a physically demanding job, and women tended to command lower wages than men at the time. By hiring women, you could get more computing done for the same amount of money.

There were more and more projects which required more extensive computations. If you remember back to my episode on weather forecasting, the United States National Weather Forecast was created during this period, and it was originally under the control of the Army Signal Corp. 

They extensively used computers in their forecasting.

The Harvard University Observatory created a group known as the Harvard Computers. By 1880, the Harvard Computers were all women.

The women were tasked with categorizing and cataloging stars and the enormous stream of data that was coming in from astronomers.

In addition to weather and astronomical calculations, there were a host of hand calculations that were required at this time. Entire books were filled with tables of trigonometric calculations, fluid dynamics, and other engineering calculations. 

Engineers and scientists relied on these books in an era before mechanical computers existed. 

The first world war saw large teams of female computers who calculated artillery and navigation charts for the war effort. 

The way that these human computers worked is actually not dissimilar to the way that electronic computers work today. 

Computers were given very specific calculations to perform. It was usually broken down into a series of steps, aka an algorithm. Tasks were usually split up between teams, aka they were multithreaded. 

Then the same calculations would often be assigned to different groups for redundancy. If one group made an error, then, hopefully, it would be caught by the other group. 

If this process seems really slow, tedious, and time-consuming….then you can probably appreciate why machine computing was developed. 

The story of the use of computers by NASA actually starts well before the creation of NASA. It starts, in part, with the establishment of the Jet Propulsion Laboratory in California in the 1930s.

JPL’s first female computer was Barbara “Barby” Canright. She joined JPL in 1939 and was tasked with extremely difficult computations, which would often take weeks. She would have to calculate things like the efficiency of various rocket fuels or the rocket equation. 

The rocket equation, if you aren’t familiar, is the devilishly complicated equation to determine the amount of fuel needed to launch something on a rocket. Let’s say you had a 100 kilogram payload you needed to launch. That would require a certain amount of energy, which would require a certain amount of fuel. 

The problem is that fuel has mass, and it requires its own fuel, and then the container for that fuel requires fuel. It can get really complicated really fast. 

When the second world war started, a woman by the name of Macie Roberts was put in charge of JPL’s computers. They needed to significantly expand their computer program for the war effort, and Macie decided to go with a department made entirely of female computers. This was both for departmental cohesion and because there weren’t that many men available due to the war. 

Over in Virginia, the National Advisory Committee on Aeronautics or NACA, the predecessor to NASA, had established the Langley Memorial Aeronautical Laboratory. 

The Langley facility also needed a team of computers to conduct calculations from wind tunnel tests. In 1935, a core team of five women was hired to be the computers for Langely. 

In the 1940s, the team expanded due to the war effort, and the Langely facility made the highly unusual move at that time to hire African American women as computers. 

Due to the Jim Crow laws in Virginia in the 1940s, the Black female computers had to work in a different building from their white counterparts, as well as use different restrooms and lunch facilities. The program was integrated after the war when the NACA integrated all of their facilities. 

Most of the advanced calculations conducted on behalf of the war effort in World War II were done by women working as computers on the home front, at the facilities I mentioned, and at many more in factories and laboratories around the country. 

Their contribution was often recgonized by the terms which were used in measuring computing power. Instead of terms like “man hours”, some contractors adopted terms such as a “kilogirl”, a unit that reflected 1,000 hours of time spent by a computer, almost all of which were women. 

Likewise, the term “girl year” was used for larger computational projects which would require over a year of combined computing time. 

These women were the white-collar equivalent of Rosie the Riveter. 

As I explained back in my episode on the history of NASA, the 1950s saw the start of the US space program. This saw an explosion in the need for new and more computers. 

While the first electronic computers were being built in the 1950s, they were too expensive and couldn’t yet outperform a bunch of humans with pencils and paper. Human computers were still needed to perform the actual calculations which would put people and satellites into orbit.

There were electronic computers used in solving equations for space flight, however, the early engineers for NASA didn’t actually trust them. They felt that human calculations would be more accurate because that was what they had become accustomed to.

When some of the first electronic computers arrived, they were often given to human computers as it was seen to be part of their job responsibility. As such, many of the first computer programmers were the same women who were human computers.  

They were the modern-day versions of Ada Lovelace, to whom I have previously dedicated an entire episode to. 

Because the NACA and later NASA were so dependent on female computers, they adopted policies that would not be seen in the workforce for decades. 

The women who worked there received much higher salaries than they could earn elsewhere for similar office work, they were given maternity leave, albeit unpaid, and married women and women with children were employed, which was very uncommon at the time.

In the late 50s and early 60s, as the space program began to launch its most important missions, it was these women, who by now numbered in the hundreds across the country, who were responsible for calculating the orbital trajectories upon which the missions would succeed or fail. 

These computers worked on Explorer 1, the first American satellite to go into orbit. The Ranger missions, which impacted the moon and the even more complicated Surveyor missions, which soft-landed on the moon all had to be calculated by hand. 

The computers did everything for the manned missions as well, up to and including the Apollo program. 

There are several computers who deserve special mention. Katherine Johnson was a black woman who worked at the Langley facility in Virginia. She received her Ph.D. in mathematics, just the third African American in US history to do so, and went to work as a computer for the NACA in 1953. 

She quickly developed a reputation for being one of the top computers at NASA. She calculated the trajectory for Alan Shepard on NASA’s first human space flight in 1961. 

When John Glenn because the first American to orbit the Earth, he personally requested that Johnson verify the calculations performed by an electronic computer because he trusted her more than a machine. 

She became the first woman at NASA to get authorship credit for a report she helped write titled, Determination of Azimuth Angle at Burnout for Placing a Satellite Over a Selected Earth Position.

By the time of the Apollo missions, she was more than just a computer, but her skills were still requested. She verified the orbital trajectories for the Apollo 11 mission and assisted on the Apollo 13 mission when they had to calculate their return home on the fly. 

She worked at NASA until 1986, was awarded the Presidential Medal of Freedom, and was the subject of a recent movie titled “Hidden Figures” starring Taraji P. Henson. 

…and fun fact, just because I don’t know what other episode I might get a chance to mention this, Taraji Henson is the great-great-grandniece of the polar explorer Matthew Henson. 

The other woman who started her career as a computer that I should mention is Sue Finley. 

Sue Finley began her career at JPL in 1958 in the computer pool….and still works at JPL today. Today she is an engineer on NASA’s deep space network, which is the system that communicates with interplanetary spacecraft.

As of my recording this episode, she is still working full-time at the age of 85, and she is most likely the last person still employed by NASA who was a human computer. 

I’m guessing most of you can write the end of this story. By the late 60s and especially the 70s, computers had become powerful and cheap enough that humans couldn’t compete with them anymore. Engineers had overcome their initial distrust and had learned to trust the results that machines gave them. 

That is why we no longer use the term computer to refer to people anymore.

Nonetheless, for about 100 years, much of the mathematical heavy lifting which was required for fields such as engineering, astronomy, and navigation was conducted by teams of human computers, the vast majority of which were women. 

If it wasn’t for them, the modern world would look very different. 


The Executive Producer of Everything Everywhere Daily is Charles Daniel.

The associate producers are Thor Thomsen and Peter Bennett.

Today’s review comes from listener Lillie Marshall from Apple Podcasts in the United States. She writes:

So Impressive and Enlightening

I’ve followed Gary’s global education work for over a decade, and am thrilled about his Everything Everywhere Daily podcast. As a teacher and parent, I find this podcast ideal to play to help kids learn about history and the world in bite-sized 10-minute tidbits. As a lover of learning, it’s perfect for helping to energize my brain, and to reinvigorate my understanding of humanity. As a visual learner, I appreciate that show transcripts are available to supplement my listening. Oh, and Gary has the BEST voice for podcasting! Can’t wait for the next 900 episodes.

Thanks, Lillie!  Lillie, I have to confess, is actually one of my friends. We met back in 2010 in Valencia, Spain, when we were both traveling there and we hung out there for a few days. It has only taken 2.5 years, but I finally got her to listen to the podcast. 

Remember, if you leave a review, you, too, can have it read on the show.