February 20 is the anniversary of John Glenn’s historic flight in the Mercury spacecraft he named Friendship 7. He became the third American and fifth person in space, but what made his mission especially important was that he was the first American to orbit the Earth. Alan Shepard and Gus Grissom’s earlier Mercury flights, both achievements in their own right, had only been 15-minute suborbital hops. Glenn’s three circuits around the world at last equaled the Soviet Union’s achievement of orbiting Yuri Gagarin on April 12, 1961. Glenn, who passed away in 2016, became a national hero.

Now the flight of Friendship 7 has gained new resonance because it is the dramatic climax of a very popular movie, Hidden Figures, based on the book of the same name by Margot Lee Shetterly. The book details the history of a little known group of women of color at NASA and its precursor, the National Advisory Committee for Aeronautics (NACA). White female “computers” (then a job title) already worked for NACA at its founding center, the Langley Laboratory in Hampton, Virginia, as was true in other science and engineering organizations in the US and beyond. Female mathematicians using large mechanical desk calculators did elaborate but often tedious calculating work so that male aerodynamicists could concentrate on the science. In World War II, however, a labor shortage forced Langley to look beyond white women for these positions. The lab created a segregated unit, West Computing, for black women. They usually had math degrees and previously had no options in the South other than in poorly paid teaching jobs in segregated schools.

One of these women was Katherine Coleman Goble Johnson from White Sulphur Springs, West Virginia, who joined the unit in 1953. A brilliant mathematician, she was one of the first African American graduate students at West Virginia University. She probably would have gone on to a doctorate had the lack of future job prospects and family concerns not intervened. Five years after she came to Langley, the center became part of NASA and the home of America’s first human spaceflight project, Project Mercury. Katherine Goble, as she was then known, quickly graduated into doing the trajectory computations for the capsule’s orbit and for its reentry into the Earth’s atmosphere. One key question was calculating the exact position over the Earth to fire the retrorockets in order to land in the center of the ocean recovery zone. As a result of this work, Johnson (after remarriage) became the first African American female computer to have her name on a technical paper issued by Langley.

Right at this time, the center installed the first large IBM mainframe computer, foreshadowing an age when the job title would go away and the women would adapt to becoming computer scientists. In fall 1961, as the Mercury project prepared for Glenn’s launch on the Atlas intercontinental ballistic missile, Glenn asked one of the supervisors to have “the girl,” meaning Johnson, to check the reentry calculations of the new computer on the old desktop calculators—he just was not comfortable with having his fate dependent on a machine. Johnson did that extensive work, which took a couple of weeks, and became known for it in the African American press after the flight.

How do those facts compare with the movie? Hidden Figures, the motion picture, takes many liberties with history. More than three years of the Mercury program are compressed into a few months in 1961. Scenes are invented to heighten the drama, like attributing to Johnson the insight that the smaller Redstone rocket used for suborbital flights could not put the capsule in orbit—as if that was not already obvious to the NASA engineers from the outset. And in the movie, Glenn phones Langley from the launch pad to have the calculations done on an emergency basis, Mercury Control at the Cape is moved to Langley so that the actress who plays Johnson, Taraji P. Henson, can step into it, and Glenn’s flight is shortened from seven orbits to three because of a warning light that his heatshield may be loose. In fact, his mission was always three orbits, and while the warning light had flight controllers quite worried, it was not aired publicly in a way that anyone watching TV understood what was going on. I could go on about the factual inaccuracies, which are many, but how bothersome that is depends on how much one thinks dramatic license is justified to make a good movie. And it is a good movie, well-acted and inspirational. I enjoyed it even as I was exasperated by its many deviations from history, some of which are simply unnecessary.

As for Katherine Johnson, she received late-life recognition even before Hidden Figures. In 2015, President Obama gave her the highest US civilian honor, the Presidential Medal of Freedom. Her story, like those of the other women commemorated in the book and the movie, are destined to change our national narrative about the space program and the people who contributed to it. In that sense, both versions of Hidden Figures are undoubtedly important.

Michael J. Neufeld is a senior curator in the Space History Department of the National Air and Space Museum and has Friendship 7 in his collections. He vividly recalls watching the Glenn launch and landing on TV as a ten-year-old in Canada.