Katherine Johnson (1918–2020) was an African-American mathematician whose calculations of orbital mechanics as a NASA employee were critical to the success of U.S. crewed spaceflights. During her 33-year career at NASA and its predecessor, the National Advisory Committee for Aeronautics, she earned a reputation for mastering complex manual calculations and helped the space agency pioneer the use of computers to perform tasks. She worked with the Apollo program, calculating rendezvous paths for the lunar lander and command module on its flights to the Moon. Johnson's calculations were essential to the beginning of the Space Shuttle program and she also worked on plans for a mission to Mars. In 2015, President Barack Obama awarded her the Presidential Medal of Freedom, as a pioneering example of African-American women in STEM. She was portrayed by Taraji P. Henson as a lead character in the 2016 film Hidden Figures. This NASA photographic portrait of Johnson was taken in 1983.Photograph credit: NASA