In 1849, trailblazing astronomer Maria Mitchell became the first woman employed by the U.S. federal government for a non-domestic specialized skill. Hired as a “computer of Venus” for the United States Nautical Almanac, she acted as a one-woman GPS, performing mathematically rigorous celestial calculations that helped sailors all over the world navigate the oceans. A century after Mitchell paved the way for women in science, an entire ecosystem of these female “human computers” had taken root. But like the women who fought in the Civil War and the women behind the Manhattan Project, their story is largely omitted from history and their achievements uncredited.

In The Rise of the Rocket Girls: The Women Who Propelled Us, from Missiles to the Moon to Mars (public library), microbiologist Nathalia Holt reclaims the role of these unheralded women scientists in the field that has enchanted humanity’s collective imagination more powerfully than any other: space exploration.

In the 1940s, NASA’s Jet Propulsion Lab, managed by Caltech, began recruiting these “human computers” — mathematically skilled women with fingers callused from gripping a pencil eight hours a day as they performed calculations that launched the first American satellite and directed the earliest missions exploring the Solar System. When Neil Armstrong made his “giant leap for mankind,” there was womankind in the control room. When the Voyager carried humanity’s message into the cosmos, the “computers” had calculated and scrutinized its trajectory. When the science boyband of Carl Sagan, Ray Bradbury, and Arthur C. Clarke sat down to discuss Mars and the future of space exploration on national television as the Mariner 9 mission was about to become the first spacecraft to orbit another planet, the women whose meticulous computations had powered the mission were nowhere to be seen.

Every moonshot, every so-called “manned” or “unmanned” mission hailed as a feat of human ingenuity, was womanned behind the scenes. (That we continue to call space missions “manned” and “unmanned” even today, decades after Sally Ride became America’s first female astronaut in orbit against a backdrop of questions about what makeup she took aboard, is a matter on which Ursula K. Le Guin has the only adequate commentary.)

Holt came to the story of these remarkable women by a delightful happenstance — while pregnant with her first child, she and her husband found themselves swirled by the indecision of baby-name choice. Each of them had a favorite name — Eleanor and Frances — so they decided to combine the two. On a whim, Holt googled “Eleanor Frances.” She recounts:

I was surprised to find, buried in history, an Eleanor Francis Helin, born November 12, 1932. She was a scientist at NASA’s Jet Propulsion Laboratory, in charge of the program that tracked asteroids nearing Earth. Like the scientists we so often see personified in movies such as Armageddon, she hunted the asteroids that get a little too close to home. During her time at NASA, she discovered an impressive number of asteroids and comets— more than eight hundred. This was the kind of woman I wanted my daughter to share her name with. My search came up with an old black-and-white photo of her, blond bouffant hair curling at her shoulders, a timid smile as she held up an astronomy award for her asteroid discoveries.

Holt was riveted by the mystery of how many such unsung women of space-science might be hidden in history, what their lives were like in an era very different from our own, and how those lives shaped so much of what we take for granted today. So began the marvelous obsession that seeded this marvelous book.

From the first “human computers” hired in the 1940s to the women who guide Mars rovers today, Holt chronicles the extraordinary lives of these women, partway between Galileo and Ada Lovelace, as well as the complexities and contradictions with which they had to contend in reconciling the era’s gender norms with their scientific ambitions. She writes:

While we tend to think of the role women played during the early years at NASA as secretarial, these women were the antithesis of that assumption. These young female engineers shaped much of our history and the technology we have today.

Bringing to life the daily reality of these women, Holt paints one particularly emblematic vignette:

The young woman’s heart was pounding. Her palms were sweaty as she gripped the pencil. She quickly scribbled down the numbers coming across the Teletype. She had been awake for more than sixteen hours but felt no fatigue. Instead, the experience seemed to be heightening her senses. Behind her she could sense Richard Feynman, the famous physicist, peeking at her graph paper. He stood looking over her shoulder, occasionally sighing. She knew that her every move was being carefully watched, her calculations closely studied. Her work would inform mission control if the first American satellite would be a success or a crushing failure. Hours earlier, before the satellite had been launched, her boyfriend had wished her luck. He hadn’t quite gotten used to the fact that his girlfriend worked late nights as an integral part of the American space program. Before leaving, he gave her a quick kiss. “I love you even if the dang thing falls in the ocean,” he said with a smile.

The boyfriend mention midway through this scientific scintillation might at first seem jarring, but that’s precisely the point — Holt illustrates the ambivalences and confusions of a culture that was only just beginning to imagine what it might be like for women to take on new ambitions and responsibilities in addition to, but not instead of, their traditional feminine duties. This was an era when these female “human computers” competed for the Miss Guided Missile pageant crown and were still called “sweetheart” by their male colleagues, who were titled “engineers,” and when the women themselves were more likely to compliment one another on their Bette Davis haircuts than on their masterful logarithms.

That young woman plotting the path of America’s first satellite was Barbara “Barby” Canright and she was well aware that if her calculations fell short of perfection, it would spell America’s loss in the Space Race with the Soviets. Holt recreates the drama of the moment:

Her pride was similarly tied to the fate of the satellite. She’d been here at the Jet Propulsion Laboratory from its earliest days, helping to design the rockets powering the tube-shaped spacecraft that was no heavier than a toddler. Now the project’s ultimate fate was hers to reveal. As she plotted a curved line across the orange graph paper, she realized the trajectory was coming close to the point of no return. If the satellite passed this point, it would leave the atmosphere, begin circling the globe, and become the first American space-success story. The future of space exploration rested on this moment.

But neither failure nor triumph distracted Barby from the task at hand:

When she calculated that the satellite had left Earth’s atmosphere, the critical juncture, she kept quiet. She made no comment but couldn’t help letting a smile come to her lips. “Why are you smiling?” Feynman said, his voice irritated as the moments crept by. Until the signal came through in California, after the satellite had completed a spin around Earth, they couldn’t be sure the satellite would stay up. Everyone was on edge as they waited for the confirmation of a few faint beeps, proof that they’d made it. The pounding of the Teletype filled her ears. The numbers came in. Suddenly the satellite’s signal came through loud and clear, breaking its long silence. She confirmed her calculations before marking down the updated position on the graph paper. “She made it!” she said triumphantly, twisting around in her seat to see the reaction. Behind her, a room of her colleagues, almost all men, broke into cheers. Ahead of her, the future stretched out, as limitless as space itself.

But where science saw boundless possibility, culture presented a number of limits seeded by a failure of the imagination — a failure of even the most fertile imaginations. Barby and her generation of scientists had come of age at a time when rocket-building was considered a borderline ludicrous endeavor — even by the great Vannevar Bush, who headed America’s Office of Scientific Research and Development during WWII and envisioned the Internet in 1945. Holt quotes him to have once scoffed:

I don’t understand how a serious scientist or engineer can play around with rockets.

The early rocket-builders at Caltech — a small group of dreamers and daredevils known as the Suicide Squad — had gotten the first installment of their first $1,000 funding in crumpled up one- and five-dollar bills delivered by bicycle. But the few women who bought into this improbable dream — women with wonderfully old-fashioned names like Macie, Melba, and Virginia — became instrumental in making it a reality.

Macie Roberts was a particularly pivotal figure in this growing groundswell of women computing the cosmos. Holt captures her character:

Macie, perhaps because she was twenty years older than her fellow computers and obsessed with using precise terminology, would get annoyed if someone mistakenly called a rocket propellant “fuel.” She had come to engineering late in life, after working as an auditor for the Internal Revenue Service, and so had taken her lessons in rocket science to heart. In her strict and proper way she would gently remind the transgressor that a propellant is not composed of fuel alone. It also includes an oxidizer, an element such as oxygen that is able to accept an electron, thus setting in motion a powerful oxidation-reduction reaction, often called a redox reaction. These reactions, in which electrons are transferred, create energy whether they occur in a rocket engine or in a cell in the human body. […] With Macie to lead them, a group of young women were about to leave the lives expected of them. Each would go from being an oddity in school, one of only a few girls who flourished in calculus and chemistry classes, to joining a unique group of women at JPL. The careers they were about to launch would be unlike any other.

What these women went on to launch was something larger than their own careers. Holt writes:

On July 20, 1969, Neil Armstrong and Buzz Aldrin were the first humans to tread on another planetary body. The computers’ fingerprints were all over the historic mission. Their legacy began with the rocket that flew the men up there. It blasted off in stages, a technique made possible by the women’s computations for the world’s first two-stage rocket, JPL’s Bumper WAC.

The following year, as women celebrated the fiftieth anniversary of the right to vote, a massive movement called the Women’s Strike for Equality broke out across forty states. Women marched down New York’s Fifth Avenue bearing signs that read WE ARE THE 51% MINORITY and HOUSEWIVES ARE SLAVE LABORERS. Holt conveys the tumult of the times:

Although the changes prompted confusion for some, the effects of women’s liberation were spreading everywhere, even to the offices of JPL. The women’s titles were shifting. Known as computers since the lab’s inception, they were now officially engineers. It was a breakthrough as big as landing on the moon.

But this gave rise to a new Catch-22: While the original “human computers” at JPL were grandfathered in — or, to amend yet another culturally accepted use of gendered language, grandmothered in — as engineers, new recruits were required to have actual university degrees in engineering. This, Holt points out, at first contracted rather than expanding the opportunities for women at JPL — major universities had only just begun to accept women into their engineering programs, something Caltech itself had done that very year, and women accounted for 1% of the country’s engineering degrees in 1970.

And yet JPL had become an oasis of meritocracy for the women who had by then proven themselves as brilliant scientists. Holt writes:

The women at JPL had created their own equality. They had formed the lab in their own image, building an environment welcoming to women, where their work and contributions were every bit as valued as those of their male counterparts.

In the remainder of the thoroughly wonderful The Rise of the Rocket Girls, Holt goes on to profile more than a dozen of these trailblazing women, examining how their untold story illuminates the broader cultural context of changes that are still ripening today. Complement it with Virginia Woolf on gender in creative culture, Nikola Tesla’s feminist vision for how technology will empower women, and pioneering astronomer Maria Mitchell on women in science.