Katherine Johnson

Katherine Johnson an American mathematician (1918-2020) whose precise computations of orbital mechanics were essential to the early space program of the United States. Working for the National Aeronautics and Space Administration and its predecessor, she calculated the trajectories that carried the first Americans into space and to the Moon.

Early Life and Education

Katherine Coleman was born in 1918 in White Sulphur Springs, West Virginia, the daughter of a farmer and a teacher. She showed an exceptional talent for mathematics from an early age and attended high school on the campus of West Virginia State College, where she was permitted to take advanced courses because no local school offered the instruction she needed.

She graduated from West Virginia State College in 1937 at the age of eighteen with degrees in mathematics and French, and she then taught school for several years. In 1939 she was one of three black students chosen to integrate the graduate program of West Virginia University, but she left after a year to raise a family and returned to teaching.

In 1953, after hearing that the National Advisory Committee for Aeronautics was hiring mathematicians, she applied and was hired as a research mathematician at the Langley Research Center in Hampton, Virginia. She joined the pool of women known as computers, calculating flight data by hand, and she soon attracted notice for her accuracy and her curiosity.

The West Area Computers and the Flight Research Division

Johnson was assigned to the West Area Computing section, a segregated unit of black women who performed calculations for the laboratory. For a time she worked as a computer, but she was frequently lent out to the flight research division, where her abilities were appreciated, and she asked to remain there permanently. Her request was granted, an unusual step at the time.

She worked on the analysis of gust alleviation, the effect of air turbulence on aircraft, and contributed to the reporting of a conference on the subject. As the laboratory turned to space exploration, her skills were directed to the problems of flight beyond the atmosphere, and she became known for the care with which she checked the work of others and the speed with which she mastered new areas.

She broke the practice that women should not put their names on technical reports. In 1960 her report on the equations for the trajectory of a spacecraft was one of the first from the division to carry a woman's name as author, and it became a standard reference for engineers working on the early projects of the space program.

Project Mercury and the First American Flights

For the flight of Alan Shepard in 1961, the first American in space, Johnson computed the trajectory of the capsule and verified the electronic calculations. She was called upon to confirm the numbers produced by the machines, and for the flight of John Glenn in 1962 the astronaut asked that she personally check the electronic computer before he would agree to go, saying that if she said the figures were good he was ready.

Her calculations covered the path of the capsule from launch to splashdown, the timing of retrofire and the effects of the changing mass of the spacecraft as fuel was consumed. She worked with a mechanical desk calculator and with early electronic machines, and her results were the standard against which the new computers were judged. Her confidence in the arithmetic gave the pilots confidence in their missions.

She also calculated the impact point of the capsule and the tracking network needed to follow it. Her work under the pressure of the accelerating space race, done with instruments that would today seem impossibly simple, contributed directly to the success of the Mercury program and to the survival of the astronauts it carried.

Apollo, the Moon and Later Work

Johnson went on to work on the trajectories of the Apollo missions. She calculated the path of the lunar module as it separated from the command module and descended to the surface of the Moon, and she computed the return path that would bring the spacecraft back to Earth. Her work helped to make the landing of 1969 possible and to bring the crew safely home.

She also contributed to the Space Shuttle program and to planning for a proposed mission to Mars, and she served on committees charged with the accuracy of the data used in flight. She was a co-author of numerous technical papers, and she calculated for a span of decades that covered the transformation of spaceflight from a fragile experiment into a routine enterprise.

She retired from the space agency, now the National Aeronautics and Space Administration, in 1986 after thirty-three years of service. In her later years she was recognised as a pioneer whose contribution had been too little acknowledged, and the story of her life and of her colleagues among the black women computers became the subject of books and films.

Recognition and Legacy

Johnson received the Presidential Medal of Freedom in 2015 and the Congressional Gold Medal in 2019. The space agency named a research building and later a spacecraft after her, and her image and story were carried into popular culture by a book and a film about the women who computed for the space program. She was celebrated as a symbol of the overlooked contributors to American science.

Her achievements were won against the barriers of both race and sex, in a workplace that was segregated and in a field that favoured men. She insisted throughout her life that her work was its own reward and that she had simply done her job, a modesty that her admirers saw as inseparable from the seriousness of her contribution.

She died in 2020 at the age of one hundred and one. Her legacy includes not only the trajectories she computed but the doors she opened, and the demonstration that ability and diligence deserve recognition whatever the circumstances of their possessor. Her name has become a byword for the invisible labour that makes great enterprises possible.

See also

• Project Mercury
• Apollo program
• Langley Research Center
• Human computer