Katherine Johnson: The Woman Who Checked the Computer
In February 1962 John Glenn was preparing to become the first American to orbit the Earth, and he did not trust the IBM machines that had generated his orbital equations. "Get the girl," he told the engineers, and if she confirmed the numbers, he would fly. "If she says they're good," Johnson remembered him saying, "then I'm ready to go." The girl was a forty-three-year-old mathematician named Katherine Johnson, and she took the machine's output and worked the equations through by hand.
A Child Who Counted Everything
Johnson was born on 26 August 1918 in White Sulphur Springs, West Virginia. Her mathematical ability appeared early and was impossible to ignore; she was advanced several grades past children her own age. At thirteen she was attending high school on the campus of West Virginia State College. At eighteen she was enrolled in the college itself.
A Mentor and a Degree
At West Virginia State she came under the tutelage of Dr. W. W. Schieffelin Claytor, the third African American to earn a PhD in mathematics, who recognised what he had and taught accordingly. She graduated in 1937 with highest honours, holding a degree in mathematics and French.
In 1939 the state of West Virginia selected Johnson and two men to become the first Black students to integrate its graduate schools. She enrolled in the graduate mathematics programme at West Virginia University — and then left after a single session to start a family with her first husband, James Goble. It is one of the quieter losses in the record: the most gifted mathematician in the room withdrawing from it for reasons that had nothing to do with mathematics. She went back to teaching in a Black public school in Virginia once her three daughters were older, and stayed there until 1952.
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In the summer of 1953 Johnson joined the all-Black West Area Computing section at the NACA's Langley laboratory, a unit of women who performed calculations by hand and were themselves called computers. It was headed by Dorothy Vaughan. Johnson lasted two weeks there before being assigned, permanently, to the Maneuver Loads Branch of the Flight Research Division, where she analysed flight test data and investigated the causes of crashes traced to wake turbulence.
When Sputnik went up in 1957, her calculations fed into the document *Notes on Space Technology*. In 1960 she and the engineer Ted Skopinski co-authored "Determination of Azimuth Angle at Burnout for Placing a Satellite Over a Selected Earth Position" — the first time a woman in the Flight Research Division had received author credit on a research report. She would author or co-author twenty-six in all.
Freedom 7 and Friendship 7
In May 1961 she performed the trajectory analysis for Alan Shepard's Freedom 7, the first American human spaceflight. The following February came Glenn's orbital mission and the hand verification that has become the most retold episode of her life. Friendship 7 flew successfully, and the flight marked a turning point in the American contest with the Soviet Union.
Apollo and After
Johnson herself did not name the Glenn episode as her most important work. She pointed instead to the calculations that helped synchronise the Apollo Lunar Module with the Command and Service Module in lunar orbit — the rendezvous problem, on which the survival of the crew and the success of the 1969 landing depended. She later worked on the Space Shuttle and on the Earth Resources Technology Satellite, the programme that became Landsat.
She retired in 1986 after thirty-three years at Langley. Her summary of the whole period was characteristically plain: "I loved going to work every single day." In 2015, at ninety-seven, she received the Presidential Medal of Freedom from President Barack Obama. She died on 24 February 2020, aged 101. NASA's administrator, Jim Bridenstine, called her "an American hero" whose "pioneering legacy will never be forgotten."
Why Katherine Is Called a Genius
The faculty is specific and demonstrable: an exceptional command of analytic geometry applied to orbital mechanics, combined with an accuracy under pressure that engineers trusted more than they trusted their machines. That last point is the heart of it. In 1962 the electronic computer was new and its output was suspect, and the resolution of that doubt was to hand the problem to one person and accept her answer. Very few mathematicians in history have been treated as the authoritative check on a machine, with a man's life resting on the result. The precocity was real too — grades skipped, high school at thirteen, a double-honours degree at nineteen — and so was the persistence: she broke into a segregated graduate school in 1939 and, two decades later, became the first woman in her division to be credited as an author.
The honest counter-case matters. Johnson did not develop new mathematics; she applied existing celestial mechanics with unusual exactness, and she worked inside a large team of highly capable people, many of them women in the same computing pool whose names are far less known. The popular version of her story, shaped by the book and the 2016 film *Hidden Figures* in which Taraji P. Henson played her, compresses years of collective engineering into a few dramatic scenes and inevitably overstates the role of a single desk. Her celebrity arrived only in her late nineties, and part of what the word "genius" is doing in her case is repairing a long historical silence rather than describing an intellectual singularity. Johnson's own preference — citing the Apollo rendezvous calculations over the Glenn story — suggests she understood the difference perfectly well.
Legacy
Johnson's numbers are embedded in the flight paths of the first Americans to leave the atmosphere and the first to leave Earth's orbit for the Moon. Her wider legacy is the destruction of an assumption: that the intellectual work of the space programme belonged to white men, and that everyone else was support staff. NASA has since named facilities for her, and the phrase "hidden figure" has entered the language to describe exactly the kind of person she was — indispensable, uncredited, and eventually impossible to leave out of the story.
Achievements
- Calculated the trajectory for Alan Shepard's 1961 spaceflight, the first by an American
- Verified the orbital calculations for John Glenn's 1962 Friendship 7 flight at the astronaut's personal request
- Contributed trajectory work to the Apollo 11 Moon landing and the Apollo 13 mission
- Awarded the Presidential Medal of Freedom (2015) and Congressional Gold Medal (2019)
