Women in Science: Hidden Figure Katherine Johnson, NASA's Human Computer

In honor of International Women’s Day this week, Ask Science highlights the work of Katherine Johnson.

Sabrina Stierwalt, PhD
5-minute read
Episode #229

In honor of International Women’s Day this week, let’s highlight the work of Katherine Johnson, math teacher, NASA human computer, and inspiration for Margot Lee Shetterly’s recent book and the feature film, Hidden Figures. What does it mean to be a “human computer” for NASA? How are launch dates and flight paths for spacecraft determined?

Katherine Johnson

By the age of 10, Katherine had taken all of the classes her hometown of White Sulfur Springs, West Virginia had to offer black students at the time, the equivalent of an eighth grade education. So her father moved the family over 100 miles away so that she could attend high school, and she later graduated from West Virginia State College (now West Virginia State University) with degrees in mathematics and French at the age of 18.

Her exceptional schooling record did not stop there. In 1939, along with two male students, she then bravely became the first to desegregate the graduate program at West Virginia University. However, she only stayed in the program for less than a year. By some accounts, she left to start a family, while others suggest the environment was not as welcoming as her undergraduate experience.

Johnson worked as a public school teacher of mathematics, French, and music in Worked as teacher of math and French and music until she earned a spot as a “human computer” in 1953 at what is now the Langley Research Center in Hampton. There she worked alongside and under Mary Jackson and Dorothy Vaughn, whose efforts are also highlighted in Hidden Figures.  

Katherine soon moved to Langley’s Flight Research Division where she worked on complex mathematical problems like investigating a plane crash caused by wake turbulence. National focus soon shifted quickly, however, when the Soviet satellite Sputnik was launched in 1957 amidst the Cold War between the US and the USSR. The US responded to what NASA refers to as “the Sputnik crisis” by creating the National Aeronautics and Space Administration, and the space race was on. Katherine Johnson was among the first ~8,000 NASA employees.

Calculating Orbital Trajectories Is Women’s Work

In the early years of NASA, the challenging work of complex, multivariable computations, work which required incredible focus and attention to detail, was assigned to groups of women known as “human computers”. In fact, as the first electronic computers were being introduced, programming the machines was considered women’s work.

One such computation was determining the most efficient path for spacecraft – a path that used the least amount of fuel, avoided other solar system bodies while in flight, and ended with a landing in a pre-designated location.  You don’t have to have taken an orbital mechanics class to know these equations are not simple. The Earth’s atmosphere provides drag. The weight of your rocket changes as you burn fuel to leave that atmosphere. The Earth is rotating. You don’t want to hit the Moon, but the Moon keeps moving! Thanks to all of these complications, and many others, the related computations generally cannot be done analytically, but instead must be done numerically. For a visual, check out this video of the Voyager flight paths as they avoid running into solar system bodies while still using them for the occasional gravity assist.

In 1961, only a few years after NASA’s formation, Alan Shepard became the first American to travel into space (the second person after Soviet cosmonaut Yuri Gagarin) as part of the Mercury-Redstone 3 mission, and the path for his flight was calculated by Katherine Johnson. In 1962, John Glenn became the first American to orbit the Earth on board the Friendship 7 spacecraft, a mission with a trajectory significantly more difficult to calculate.

At the time, orbital flight path determination was so complex that a worldwide communications network that linked tracking stations around the world to computers in Washington, D.C. and Cape Canaveral, had been developed to control the trajectory of Glenn’s Friendship 7 mission capsule. However, astronauts generally did not trust these electronic calculators, machines known to be “prone to hiccups and blackouts”, with their lives, and John Glenn reportedly asked that the calculations be checked by Katherine Johnson and her colleagues before he would trust them.

The success of Alan Shepard’s and John Glenn’s missions, which relied heavily on Katherine Johnson’s work, served as a turning point in the space race between the US and the USSR. During her tenure at NASA, Katherine Johnson also provided trajectory work for the Lunar Orbiter program that mapped the surface of the Moon in preparation for the Moon landing a few years later. She then calculated the orbital trajectory for the Apollo 11 mission that famously brought astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins to the Moon (and back!), which remains the farthest humans have ever traveled in space. After an exploding oxygen tank prevented the Apollo 13 mission from reaching the Moon, Johnson aided in determining the orbital trajectory to bring the astronauts on board back to safety.


Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.