Historic NASA mathematician Katherine Johnson has died at age 101

NASA mathematician Katherine Johnson, one of the space agency's 'hidden figures,' has died at the age of 101, NASA revealed on Monday. Johnson's career had started at the National Advisory Committee for Aeronautics, the predecessor to the agency now known as NASA. The most notable part of Johnson's career, she said at various points in her life, was her work as part of the Project Apollo space program.

Johnson's career began in 1953 at NACA, later transitioning to her work with NASA from which she retired in 1986. On a memorial page set up on the NASA website, the space agency explains that Johnson did trajectory analysis for the Freedom 7 human spaceflight mission that took place in 1961.

In addition to a number of other achievements throughout her career, Johnson was asked to manually crunch the equations that had been programmed into the computers designed to control the trajectory of John Glenn's Friendship 7 capsule that orbited the Earth. NASA explains on its website:

The computers had been programmed with the orbital equations that would control the trajectory of the capsule ... but the astronauts were wary of putting their lives in the care of the electronic calculating machines, which were prone to hiccups and blackouts ... 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.

The flight was ultimately successful, making Glenn the first person to orbit the Earth. In addition to the work on calculations that helped sync the Lunar Module with the Command and Service Module under the Apollo Program, Johnson also worked on the Earth Resources Satellite and the Space Shuttle.

As well, Johnson was the co-author and author of 26 research reports and she was awarded the Presidential Medal of Freedom in 2015 at the age of 97. In a tweet, NASA Administrator Jim Bridenstine said, "She was an American hero and her pioneering legacy will never be forgotten."