Katherine Johnson was an American mathematician whose calculations of orbital mechanics as a 35-year NASA employee were critical to the success of the first and subsequent U.S. crewed spaceflights. NASA noted her “historical role as one of the first African-American women to work as a NASA scientist.”

From NASA:

The 1957 launch of the Soviet satellite Sputnik changed history—and Johnson’s life. In 1957, she provided some of the math for the 1958 document Notes on Space Technology, a compendium of a series of 1958 lectures given by engineers in the Flight Research Division and the Pilotless Aircraft Research Division (PARD). Engineers from those groups formed the core of the Space Task Group, the NACA’s first official foray into space travel. Johnson, who had worked with many of them since coming to Langley, “came along with the program” as the NACA became NASA later that year. She did trajectory analysis for Alan Shepard’s May 1961 mission Freedom 7, America’s first human spaceflight. In 1960, she and engineer Ted Skopinski coauthored Determination of Azimuth Angle at Burnout for Placing a Satellite Over a Selected Earth Position, a report laying out the equations describing an orbital spaceflight in which the landing position of the spacecraft is specified. It was the first time a woman in the Flight Research Division had received credit as an author of a research report.

In 1962, as NASA prepared for the orbital mission of John Glenn, Johnson was called upon to do the work that she would become most known for. The complexity of the orbital flight had required the construction of a worldwide communications network, linking tracking stations around the world to IBM computers in Washington, Cape Canaveral in Florida, and Bermuda. The computers had been programmed with the orbital equations that would control the trajectory of the capsule in Glenn’s Friendship 7 mission from liftoff to splashdown, but the astronauts were wary of putting their lives in the care of the electronic calculating machines, which were prone to hiccups and blackouts. As a part of the preflight checklist, Glenn asked engineers to “get the girl”—Johnson—to run the same numbers through the same equations that had been programmed into the computer, but by hand, on her desktop mechanical calculating machine.  “If she says they’re good,’” Katherine Johnson remembers the astronaut saying, “then I’m ready to go.” Glenn’s flight was a success, and marked a turning point in the competition between the United States and the Soviet Union in space.

Katherine Johnson