NASA research mathematician Katherine Johnson is photographed at her desk at Langley Research Center in 1966. Johnson began her career in 1953, and spent more than three decades as a mathematician at NASA and its predecessor, NACA, the National Advisory Committee for Aeronautics. She was one of a number of African-American women hired to work as "computers" in what was then NACA's Guidance and Navigation Department. Johnson worked at Langley from 1953 until her retirement in 1986, making critical technical contributions which included calculating the trajectory of the 1961 flight of Alan Shepard, the first American in space.