ASSESSING the part women have played in the development of science is not easy. Historians must navigate by the documents available to them. Often, the best preserved information is financial. So inattentive writers tend to underestimate the contributions of women who achieved recognition from their peers while they were financially dependent on their families, like neurologist Cecilia Vogt or marine biologist Jeanne Villepreux-Power.

But if even intellectual celebrities get forgotten, is it any wonder that we forget the women whose contributions are hard to assess for other reasons?

Roles and titles evolve, and some jobs that appear mundane to us were not so back then. Once upon a time, 鈥渃omputers鈥� were human, and often female; but these women weren鈥檛 drudges. Two recent biographical histories explore the careers of the women who made modern astronomy and space science possible. Theirs were not easy lives by today鈥檚 standards, but they were not without light and shade, rewards and recognition.

鈥淥ne calculator was a maid. She went on to discover 10 new stars and classify more than 10,000 stars鈥�

Dava Sobel鈥檚 The Glass Universe starts in Harvard College Observatory, where Edward Pickering was just 30 years old when he became director in 1877. He was fond of saying that 鈥渁 magnifying glass will show more in the photograph than a powerful telescope will show in the sky鈥�. It was an outlook that left a legacy of half a million photographic plates and some seminal discoveries.

Sobel describes each of these slices as 鈥渁 little piece of heaven鈥�, 8 inches by 10 inches, which together constituted a universe captured on glass. Men might have taken the photographs, but it was a remarkable and talented group of 鈥渃omputers鈥� who analysed and decoded the information they contained.

Pickering, a champion of the new field of photometry, wanted to establish a stellar brightness scale based on observations of stars whose brightness varies over time. Two widowed heiresses, Catherine Wolfe Bruce and Anna Palmer Draper, provided the funds. Draper in particular wanted a catalogue of stellar spectra as a tribute to her husband, an accomplished stellar photographer.

Initially, female relatives of male observatory workers were employed as computers, but soon recruits included graduates from the fledgling women鈥檚 colleges. One remarkable calculator came from far humbler origins, however: Williamina Fleming was a maid hired by Pickering鈥檚 wife. Fleming鈥檚 natural abilities were quickly recognised. She went on to discover 10 stars, some 300 stars with variable brightness, and to classify more than 10,000 stars using a system that she devised herself. In 1899, she was appointed Harvard鈥檚 curator of astronomical photographs.

Two years later, Annie Jump Cannon became the first woman allowed to operate the telescopes at the observatory, and she developed the system of stellar classification that is still used today: O, B, A, F, G, K, M. Generations of students have learned to memorise the disorderly string of letters using the unfortunate phrase: 鈥淥h, Be A Fine Girl, Kiss Me鈥�.

In 1912, Henrietta Swan Leavitt discovered a pattern in the brightness of a group of pulsing stars called the Cepheid variables. This was an integral part of Edwin Hubble鈥檚 discovery that the Milky Way wasn鈥檛 the only galaxy, and that the universe was expanding. Some members of the Royal Swedish Academy of Sciences wanted to nominate Leavitt for the 1926 Nobel prize only to discover that she had died in 1921.

A Nobel prize really should have gone to English-born Cecilia Payne in 1925, for her discovery that hydrogen was the most abundant constituent of stars. It at least earned her the first PhD in astronomy that Harvard awarded to a woman, and in 1956 she was the first female to get a full professorship at the university.

鈥淗uman computers no longer measured stars, but helped calculate the path to the moon鈥�

On 5 October 1957, the Soviet Union launched Sputnik, the world鈥檚 first orbital satellite. By then, computers no longer simply took the measure of the stars, but were mathematicians, helping to calculate the path to the moon. Margot Lee Shetterly鈥檚 father was a NASA scientist for 40 years and worked at the Langley Research Center in Virginia. He told his daughter stories of the black female computers who did calculations for engineers while segregated from their white colleagues. Young Shetterly 鈥渒new so many African Americans working in science, math and engineering that I thought that鈥檚 just what black folks did鈥�.

Hidden Figures tells their story. It鈥檚 an engaging read, and a film adaptation is already on general release in the US. Shetterly weaves together the personal and professional stories of a group of extraordinary women into an account of how they overcame race and gender barriers, while helping to win the space race.

鈥淲hat black folks did鈥�

鈥淢ississippiitis鈥� looms large 鈥� a term coined by The Chicago Defender newspaper at the time to capture the 鈥渄isease of segregation, violence and oppression that plagued America like a chronic bout of consumption鈥� and which was, for some, the reason the country had fallen behind the Soviets.

Shetterly celebrates the skills, achievements and tenacity of women like Dorothy Vaughan, Katherine Johnson and Mary Jackson as they helped launch rockets and humans into space.

In 1953, Vaughan was at the National Advisory Committee for Aeronautics, the precursor of NASA, heading a department of black female computers. They were joined by Katherine Johnson, the woman who helped put John Glenn into orbit and mapped the trajectory for Apollo 11鈥檚 moon landing, among other firsts.

There鈥檚 an easy moral here: that Neil Armstrong鈥檚 鈥済iant leap for mankind鈥� will only loom larger in our imaginations once we appreciate all the people 鈥� men and women 鈥� who got him there.

by Dava Sobel, 4th Estate

by Margot Lee Shetterly, HarperCollins

This article appeared in print under the headline 鈥淭he women who figured a way to space鈥�