Katherine Johnson

Katherine Johnson (26 August 1918 – 24 February 2020) was an American mathematician whose calculations of orbital trajectories supported NASA's crewed spaceflights from the Mercury programme through the Apollo era. She worked at the Langley Research Center in Virginia for thirty-three years 1.

She was one of the African American women employed as human computers, performing the numerical work that engineers and astronauts depended on, at a time when segregation and sex discrimination limited their opportunities. Her accuracy became a byword: before his 1962 orbital flight, John Glenn asked that she personally check the electronic computer's figures 2.

Her later recognition, including the Presidential Medal of Freedom in 2015, came decades after her retirement and made her a symbol of the overlooked contributors to the space programme.

Katherine Coleman was born on 26 August 1918 in White Sulphur Springs, West Virginia, the youngest of four children. Her father worked in farming and lumber; her mother was a teacher. She showed an early aptitude for counting and mathematics, and because the local school did not offer secondary education for Black students, her family moved to be near a high school that did 1.

She enrolled at West Virginia State College at fifteen and graduated in 1937 with degrees in mathematics and French, summa cum laude. In 1939 she was selected as one of the first Black students admitted to the graduate programme at West Virginia University, but she left after a year to teach 2.

She taught school in Virginia for several years and, in 1953, joined the National Advisory Committee for Aeronautics at Langley as a mathematician in the West Area Computing section, a segregated unit of Black women who performed calculations for engineers 3.

Within two weeks she was reassigned temporarily to the Flight Research Division, where she analysed data from crash tests and aircraft. She stayed, and in 1958, when NACA became NASA, she became the first woman in the division credited as an author of a technical report. She later co-authored more than two dozen reports on trajectories and guidance 1.

In 1962 John Glenn became the first American to orbit the Earth. NASA had begun using electronic computers for trajectory work, but the machines were new and their output was not fully trusted. Glenn asked that Johnson verify the numbers by hand, and she did, checking the trajectory and the capsule's re-entry path 4.

The episode became the best-known illustration of her role, though it was one of many. She had already calculated the trajectory for Alan Shepard's suborbital flight in 1961 and would go on to work on the Apollo programme, where her calculations helped determine the lunar module's path and the timing of the return to Earth 2.

Johnson worked on the Apollo missions throughout the 1960s and 1970s. She calculated trajectories for the lunar landings and, after the Apollo 1 fire, contributed to the reviews that reshaped the programme's safety procedures. For Apollo 13, when an oxygen tank exploded, her earlier work on backup procedures formed part of the effort to bring the crew home 5.

She also worked on the Space Shuttle programme and on plans for a Mars mission before retiring from NASA in 1986. Her technical reports dealt with trajectory analysis, launch windows, and the mathematics of rendezvous, and several remained standard references within the agency 1.

Johnson's work was largely unknown outside NASA until the 2010s. Margot Lee Shetterly's book Hidden Figures (2016), and the film released the same year, brought the West Area Computers to public attention. NASA named a building at Langley the Katherine Johnson Computational Research Facility in 2016 3.

In 2015 President Barack Obama awarded her the Presidential Medal of Freedom, and in 2019 she received the Congressional Gold Medal. West Virginia State University named a scholarship and a residence hall for her, and her alma mater awarded her an honorary doctorate. She died in 2020 at the age of 101 2.

Johnson's career illustrates both the contribution of human computers and the barriers that kept them out of view. She was paid less than her white colleagues, worked in segregated facilities, and had to petition to attend meetings; her persistence made her a model for later generations of women in science and engineering 1.

Her legacy is also technical. The hand calculations she and her colleagues produced were the checks against which the first electronic computers were validated, and the transition from human to machine computation depended on people who could do both. Her papers and oral histories are held by the Library of Congress and by West Virginia State University 2.

The building named for her stands beside the runways at Langley, where she worked for thirty-three years. For a mathematician whose name was once absent from the reports she wrote, the recognition is late but durable 3.