“Get the girl to check the numbers.” These words came from astronaut John Glenn in February 1962 as he prepared to become the first American to orbit the Earth. The trajectory of his orbit had been calculated by NASA’s new state-of-the-art computers, but Glenn did not trust the machines.
Mercury 7 astronauts had always relied on “computers in skirts,” women who were mathematicians at NASA’s Langley Research Center in Hampton, Va., for such flight data. So before he made his historic voyage into space, Glenn called on Katherine Johnson to recheck the computer’s analysis, knowing that she had provided similar calculations for Alan Shepard, the first American in space. Johnson, one of the few African-American women then working for NASA, calculated and confirmed the data for Glenn’s orbit. The launch went ahead and Glenn became the first American to orbit the Earth, 10 months after the Soviet Union’s Yuri Gagarin was the first human being to make that journey.
Johnson’s role was little recognized at the time, but she would go on to play a significant—though, again, largely hidden—role in the first moon landing and in U.S. space exploration in the 1970s and 1980s. She did so by doing what she had always loved: math.
From as early as she could remember, Katherine Johnson loved to count. Born Katherine Coleman in White Sulphur Springs, W.Va., in 1918, she counted the number of steps from her house to church and counted dishes as she washed them. She loved that with math “you’re either right or wrong.” Her mother, Joylette, was a teacher, but she credits her father, Joshua, a farmer and janitor, for her skill with numbers.
Joshua Coleman had left school in the sixth grade, but just by looking at a tree he could calculate how many boards could be gotten from it. He could figure out math problems that stumped Katherine’s teachers at the local school for blacks, which went up only to the eighth grade. Ambitious for his daughter, Joshua Coleman remained in White Sulphur Springs during the school year while Joylette, Katherine and her three older siblings lived 125 miles away near Institute, home to a high school connected to the HBCU now known as West Virginia State University.
Ten years old when she entered the best high school for African Americans in the state, Katherine was inspired by her principal, who encouraged her interest in math and astronomy. After high school she won a full scholarship to West Virginia State College, graduating at age 18 with bachelor’s degrees in mathematics and French in 1937. Although one of her professors, W.W. Schiefflin Claytor, one of the first blacks to earn a Ph.D. in mathematics, had piqued her interest in mathematical research, job opportunities in that field would have been virtually nonexistent for an African-American woman at that time.
With no interest in nursing, she chose the only other route available for black women with degrees in science in the 1930s: teaching. She taught in both West Virginia and Virginia, experiencing in the latter state a harsher version of Jim Crow than she had grown up with. She also married James Francis Goble, raised three children with him and nursed him through a prolonged illness until his death in 1956. In 1959 she married a Korean War veteran, Lt. Col. James A. Johnson.
By then Katherine Johnson had been working for NASA at Langley for six years. She began there in 1953 with the National Advisory Committee for Aeronautics as part of its pool of female “computers”—akin to a secretarial pool—who performed the mathematical calculations once performed by aeronautic engineers. Women had been, in Johnson’s memorable phrase, “computers with skirts” since 1935. During World War II, NACA also began hiring African-American women with degrees in math and science as part of President Franklin Roosevelt’s Executive Order 8802, which prohibited racial discrimination in hiring within the U.S. defense industry and established a precedent for future civil rights laws.
Johnson became the first woman and first person of color in the Space Task Force to perform mathematical calculations for the National Aeronautics and Space Administration when it replaced NACA in 1958. Johnson impressed her new colleagues with her knowledge of analytical geometry and got them to see her as an equal by standing her ground when it mattered, notably by insisting that she attend higher-level meetings and briefings because, as she pointed out, there was no law to prevent it.
Johnson’s greatest expertise was in calculating the trajectories for space launches and landings. In 1997 Johnson recalled Alan Shepard’s suborbital mission as “easy … it was just a matter of shooting him up and having him come back down. The major difficulty was making sure that he landed in the ocean and not on land.”
A similar calculus applied to Glenn’s orbit in 1962, but by the time of the first moon landing in July 1969, Johnson’s calculations had become more complex. She had to work a series of algebraic equations that related the Apollo spacecraft’s flight path to the Earth's rotation and to the moon's movements. These calculations would send Apollo into a lunar orbit, land a module on the moon's surface, return the module to the spacecraft and finally return the spacecraft to Earth.
Like millions of others across the globe, Johnson recalls where she was when Neil Armstrong made that “giant leap for mankind” with his own small step onto the moon. She was attending a sorority convention in the Poconos in Pennsylvania and watched the landing with a mix of pride and fear, knowing that the mission’s success or failure depended on her calculations.
For the early U.S. space missions, Johnson plotted emergency navigational charts to help the first astronauts guide their rockets by the stars if navigation monitors failed. These star maps allowed astronauts to determine their location in space, stay on the correct course and make any needed corrections in their flight path. These maps were particularly important in the successful return of the damaged Apollo 13 capsule, which was forced to abandon its mission to the moon in April 1970.
Johnson continued to work with NASA at Langley in the 1970s and 1980s as part of its Lunar Spacecraft and Operations team, for which she received the Group Achievement Award for pioneering work in the field of navigation. The Lunar Orbiter program produced several successful photographic flights, each returning to Earth with highly detailed images that greatly increased our understanding of the moon’s geography and terrain. Before retiring from NASA in 1986 after 33 years of service, she participated in the earliest stages of the Space Shuttle program that would become America’s main focus after the abandonment of moon exploration.
NASA recognized Johnson with special achievement awards in 1970, 1980 and 1985, and she subsequently received numerous awards for her career as a pioneering African-American woman in science, technology, engineering and math fields. Most notable of these was the Presidential Medal of Freedom, the nation’s highest civilian honor, which she received from President Barack Obama in 2015 at the age of 97.
Edited by Henry Louis Gates Jr. and Evelyn Brooks Higginbotham, the African American National Biography was first published by Oxford University Press in an award-winning, eight-volume print edition in 2008; a 12-volume second edition followed in 2012. As of 2015, more than 5,500 separate AANB entries are available online as part of OUP’s African American Studies Center.
Steven J. Niven is executive editor of the Dictionary of Caribbean and Afro-Latin American Biography, the Dictionary of African Biography, and the African American National Biography at Harvard University’s Hutchins Center for African and African American Research. He is also the author of Barack Obama: A Pocket Biography of Our 44th President.