Happy 98th Birthday, Katherine Johnson

Katherine Johnson as she received the Medal of Freedom. Johnson played a pivotal role in the American space program. She was one of the first African-American women to work at NASA (and the agency's predecessor, the National Advisory Committee for Aeronautics). A mathematician, she worked as a "human computer" performing calculations for the Mercury, Apollo, and Shuttle programs. A NASA biography of Johnson says she was so respected by her peers that "John Glenn requested that she personally re-check the calculations made by the new electronic computers before his flight aboard Friendship 7--the mission on which he became the first American to orbit the Earth."