(CNN) By the time NASA was preparing to send John Glenn into space computers were used to calculate launch conditions.

It wasn't long before then that the space agency and its predecessor, the National Advisory Committee for Aeronautics , used " computers in skirts " to do all the number-crunching.

That's right: humans, namely women, comprised the workforce known as the " Computer Pool " before the arrival of electronic data processors, aka, computers in the 1960s. Black women played a crucial role in the pool, providing mathematical data for NASA's first successful space missions, including Glenn's pioneering orbital spaceflight.

Their work barely earned a mention in pop culture space tributes until this year, thanks to a best-selling novel and a forthcoming film that's getting major Oscar buzz.

"Hidden Figures," starring Taraji P. Henson, Octavia Spencer, Janelle Monáe, tells the story of three women from the pool. The film is based on Margot Lee Shetterly's bestselling book by the same name , which spans several decades and characters at Langley.

Henson stars as Katherine Johnson, the 2015 National Medal of Freedom recipient who calculated the trajectory for America's first trip to space with Alan Shepherd's 1961 mission; Spencer as Johnson's supervisor, Dorothy Vaughan; and Monáe as Mary Jackson, who rose from mathematician to engineer to the mentor for women and minorities.

A pivotal scene in the film features Glenn. Johnson's work was held in such high regard in its time that Glenn, who died on Thursday, was aware of it. Computers were so new that even people at NASA were skeptical of them, and Glenn requested that Johnson personally confirm its calculations before his trip three times around Earth.

A day and a half later, she proved the computer right.

Considered more patient and detail-oriented than men (and they could be paid less), the first women were hired in 1935 to do the integral but time-consuming work of reading, calculating and plotting test data to free up engineers for research projects.

Following an executive order prohibiting racial discrimination in the defense industry, Langley Memorial Aeronautical Laboratory, NACA's main research center, began recruiting black people with college degrees in the 1940s for the computer pool. For years the women occupied a segregated wing, "West Area Computing," and used separate facilities. But there was no denying the value of their contribution.

In interviews ever since, Johnson has resisted taking full credit for the work. As she said in a 2010 interview , "We always worked as a team. It's never just one person."

Here's more about Johnson and her colleagues:

Katherine Johnson

Johnson was born in 1918 in White Sulphur Springs, West Virginia, where education for black people ended in eighth grade. Recognizing their youngest daughter's talent for math, her parents sent her to high school on the campus of West Virginia State Institute, a black college 100 miles away. It paid off and she graduated from high school at 14 and graduated from West Virginia State in 1937 at 18.

Katherine Johnson

Like many women of her time she became a teacher -- but her sights were set on becoming a research mathematician. When she learned of a job opening at Langley for black women with math degrees she and her husband moved their three daughters to Newport News, Virginia. She started in in the segregated West Area Computing Group in 1953 under Dorothy Vaughan. After just two weeks, she transferred to the facility's Flight Research Division. She worked there for years until the Soviet satellite Sputnik kicked off the space race between the US and the USSR, spurring the transformation of NACA into America's space agency, NASA.

She pushed her way into briefings traditionally attended only by men and secured a place in the inner circle of the American Space Program. She worked on trajectories for Shepard's Mercury flight, America's first manned spaceflight, and earned a measure of fame as "the girl" -- as female mathematicians were called -- who double-checked the output for Glenn's spaceflight. Her work helped map the moon's surface ahead of the 1969 landing and played a role in the safe return of the Apollo 13 astronauts. She retired in 1989 and lives in Virginia.

Dorothy Vaughan

Vaughan was born in 1910 in Kansas City, Missouri and graduated from Wilberforce University in Zenia, Ohio, in 1926. She was hired at Langley in 1943 in response to high wartime demand for aeronautical research data, leaving behind a job as a math teacher in Farmville, Virginia. She rose from mathematician to supervisor of West Area Computing Group, making her NACA's first black supervisor. She held onto the role, overseeing Johnson and Mary Jackson, until NACA made the transition to NASA and segregated facilities were abolished.

Dorothy Vaughn

She joined the new Analysis and Computation Division, a racially and gender-integrated group on the cutting edge of electronic computing. She became an expert FORTRAN programmer and contributed to the Scout Launch Vehicle Program before retiring in 1971. She unsuccessfully sought another management position in Langley. She died in 2008.

Mary Jackson

Jackson was born in Hampton, Virginia, in 1921. She graduated from Hampton Institute in 1942 with degrees in physical science and mathematics and became a teacher before starting her career at Langley, and later on NASA.

Mary Jackson at Work NASA Langley

She started working under Vaughan in the 1950s, focusing on processing data from wind tunnel experiments and experimental flights. Later on, she worked with flight test engineers and eventually became an engineer. As her career progressed she worked to help fellow women and minorities advance their careers through educational attainment. After 30 years she moved into administration and took a job in NASA's Equal Opportunity office, overseeing affirmative action programs and career development for women. She died in 2005.