NASA has paid tribute to the “pioneering legacy'” of mathematician and “American hero” Katherine Johnson – whose work helped put humans on the moon.
Johnson, who was portrayed in Oscar-nominated film Hidden Figures about the pioneering role of African-American women at the space agency, has died at age 101.
Her death was announced by NASA. No cause was given.
NASA administrator Jim Bridenstine tweeted: “Our NASA family is sad to learn the news that Katherine Johnson passed away this morning at 101 years old.
“She was an American hero and her pioneering legacy will never be forgotten.”
Mr Bridenstine also said the NASA family would “never forget Katherine Johnson’s courage and the milestones we could not have reached without her”.
“Her story and her grace continue to inspire the world”.
In a statement, NASA said it was deeply saddened by the loss.
“Ms Johnson helped our nation enlarge the frontiers of space even as she made huge strides that also opened doors for women and people of colour in the universal quest to explore space,” it read.
“Her dedication and skill as a mathematician helped put humans on the moon and before that made it possible for our astronauts to take the first steps in space that we now follow on a journey to Mars.”
Johnson was portrayed by Taraji P Henson in the 2016 movie Hidden Figures, a true story about trailblazing African-American women working for NASA in a racially-segregated computing unit in Hampton, Virginia.
The unit, which had signs dictating which bathrooms the women could use, was dissolved when NACA (National Advisory Committee for Aeronautics) became NASA in 1958.
Hidden Figures was named best cast at the 2015 Screen Actors Guild Awards (SAGs) and was nominated for several other awards including at the Oscars and Golden Globes.
Johnson was one of the ‘computers’ who solved equations by hand during the early years of the space race.
She focused on aeroplanes and other research before working on Project Mercury, the nation’s first human space programme.
In 2012, Johnson told The Virginian-Pilot newspaper how her office computed all of the rocket trajectories, saying she directed “where and when and how to launch it”.
She did this analysis for Alan Shepard’s 1961 Freedom 7 Mission – the first operation to carry an American into space.
The next year, she manually verified the calculations that plotted John Glenn’s orbits around the planet, with the computer-sceptical astronaut insisting she “check the numbers” before the launch.
In her 2016 book of which the movie Hidden Figures is based on, author Margot Lee Shetterly said Johnson grew phone-book-thick stacks of data sheets a number at a time, “blocking out everything except the labyrinth of trajectory equations”.
“It took a day and a half of watching the tiny digits pile up: eye-numbing, disorienting work,” she wrote, later calling Johnson “exceptional in every way”.
Johnson, along with her co-workers, was a relatively unsung hero of America’s space race until former US president Barack Obama awarded the then-97-year-old the Presidential Medal of Freedom – the nation’s highest civilian honour.
In her later years, Johnson encouraged students to enter the fields of science, technology, engineering and mathematics.
In 2008, she told NASA that looking back, she had little time to worry about being treated unequally.
“My dad taught us ‘you are as good as anybody in this town, but you’re no better’,” she said.
“I don’t have a feeling of inferiority. Never had. I’m as good as anybody, but no better.”