15 impressive women who made the Apollo moon missions possible

Years before the Apollo missions, inventor Beatrice Hicks created the critical gas-density sensor that made space travel possible. NASA used it in the Saturn V rockets that launched Apollo moon missions.

Hicks' sensor has also been also used in Boeing 707 aircraft communications systems and to monitor nuclear weapons in storage, according to the National Inventors Hall of Fame.

She co-founded the Society of Women Engineers in 1950.

Seamstresses like Eleanor Foraker sewed the astronauts' metal and plastic spacesuits by hand.

"Each suit was comprised of 21 layers of gossamer-thin fabric, sewn to a precise tolerance of 1/64th of an inch," according to CBS News.

Foraker, a senior seamstress at the International Latex Corporation (which made the Apollo suits) told The Guardian, "I would leave the plant at five o'clock in the morning and be back by seven, but it was worth it, it really was."

She added that she worked 80-hour weeks during the Apollo era, had no holidays for three years straight, and suffered two nervous breakdowns.

The Apollo astronauts' parachutes for landing back on Earth were also hand-sewn.

Margaret Hamilton led the team that created the onboard computer system for the Apollo missions. She coined the term "software engineering."

"During the early days of Apollo, software was not taken as seriously as other engineering disciplines," Hamilton recently told The Guardian. "We weren't getting credit for what was a legitimate field. It was out of desperation I came up with the term, to say: 'Hey, we're engineering too.'"

Her team's Apollo software system was so fool-proof that adaptations of it were used on the first US space station (Skylab) and during the Space Shuttle era, too.

Hamilton received a Presidential Medal of Freedom, the US's highest civilian honor, from President Barack Obama.

Mathematician Katherine Johnson worked out how Apollo 11 astronauts would get to the moon by calculating the spacecraft's trajectory.

Johnson, who is now 100 years old, was featured in the movie "Hidden Figures."

She calculated how the moon lander would meet up with the main spaceship (which stayed in lunar orbit) and drew up contingency plans, including backup navigation charts for the astronauts in case their systems failed in space.

In addition to her calculations for Apollo 11, Johnson ran trajectory analyses for Alan Shepherd's 1961 Mercury mission (the US' first human space flight). Her research on backup parameters was also instrumental in helping the crew of Apollo 13 land safely on Earth.

Sheila Thibeault worked on the Apollo's rendezvous docking simulator: the critical machine in which astronauts practiced re-attaching their lunar lander to the command module in orbit.

"It was considered very high risk," Thibeault later told MIT Technology Review. "Because if something went wrong with that rendezvous and docking, we might lose two astronauts, and there would be nothing we could do. There would be no way we could get to them."

Her success in that project was the beginning of a long and fruitful career at NASA: Thibeault is now designing protective clothing to shield astronauts from radiation.

Christine Darden was one of the many "human computer" women who processed data during the Apollo era. She wanted to know why men with the same math training were being recruited as engineers, so she asked her boss.

"Stooped by her question and impressed by her skills, her supervisor transferred her to the engineering section, where she was one of few female aerospace engineers," her NASA biography states.

Darden, who is also featured in "Hidden Figures," worked at NASA for four decades, earning her doctorate in mechanical engineering along the way. She became one of the world's leading experts in sonic boom and how to muffle it.

"She is the author of more than 50 publications in the field of high lift wing design in supersonic flow, flap design, sonic boom prediction, and sonic boom minimization," NASA says.

JoAnn Morgan, the instrumentation controller for Apollo 11, was the only woman in the firing room when the Saturn V rocket took off.

"I was there. I wasn't going anywhere. I had a real passion for it," Morgan recently told the Associated Press. "Finally, 99% of them accepted that 'JoAnn's here and we're stuck with her.'"

Morgan spent 45 years working for NASA, and was the first woman in many roles at the agency, including division chief, senior executive at the Kennedy Space Center, associate director for the Space Center, and director of safety and mission assurance.

"I look at that picture of the firing room where I'm the only woman, and I hope all the pictures now that show people working on the missions to the moon and onto Mars, in rooms like Mission Control or Launch Control or wherever — that there will always be several women," Morgan told NASA. "I hope that photos like the ones I'm in don't exist anymore."

Engineer Judy Sullivan was in charge of the biomedical system on Apollo 11, tracking the astronauts heartbeats, blood pressure, breath, and body temperature in space.

"Men were careful not to use questionable language over the loop when they knew a woman was listening," Sullivan said later in a NASA interview.

Engineer Parrish Nelson Hirasaki made sure the astronauts didn't burn up when they re-entered Earth's atmosphere. She calculated the hottest points on their heat shield.

Hirasaki was hired by NASA contractor TRW after graduating from Duke in 1967 with a degree in mechanical engineering.

She said there were only a couple other women studying engineering with her at the time, so she was often the only woman in class.

"I learned to sit in the back row of the class because if anybody was laughing about something, I'd worry it'd be about me, you know?" Hirasaki told Business Insider.

For Apollo 11, Hirasaki calculated the thousand-degree heat-shield temperatures to make sure the astronauts didn't burn up when they returned to Earth.

"I was scared to death. I said, 'No child of mine is going to be an astronaut.' I know too much," she said. "It's a dangerous business. The number of things that have to go right. It's just phenomenal."

Frances "Poppy" Northcutt was the first woman in mission control at NASA. She helped make sure the Apollo astronauts' return-trajectory calculations were sound so that they'd get home safely.

"It is an awesome feeling to see liftoff. It is just an awesome feeling because the Earth moves when you have liftoff," Northcutt later told the Houston Oral History Project.

She said she didn't feel "oppressed" by being the only woman in the room, but the experience wasn't "satisfying," either.

"I felt like I was a curiosity a lot of the times, I was stared at a lot of times," she said.

After working at NASA, Northcutt went to law school and became an attorney focused on civil rights and women's rights.

Secretaries at NASA — the "Sixties Chicks," as they called themselves — were also integral to Apollo's success, since they did most of the typing of critical reports, manuals, and checklists.

Secretaries in the 1960s had to have excellent spelling and grammar — there was no spell check and no delete button (though they did have white-out).

Secretaries like Jamye Flowers, who was hired right out of high school as a NASA secretary, ended up doing a lot of NASA's most important high-security note taking. Flowers said it wasn't uncommon to log extra-long days in the office during the Apollo era, starting at 7:30 in the morning and sticking around until 5 or 6 at night.

"Everyone worked those hours. We weren't the only ones," Flowers said during a NASA oral history project in 2008. "Everyone did. When the astronauts would be in the simulator from 8:00 in the morning 'til 5:00 in the afternoon, the time that they could get their work done, as far as what they needed to do at their desk, was after that. We all wanted to be available."

Others at a 2001 Houston Sixties Chicks reunion recalled that their own male bosses swore a lot, drank a lot of coffee, and smoked a lot of cigarettes.

And, of course, there were three women who kept things running at home while the Apollo 11 astronauts were away: Janet Armstrong, Joan Aldrin, and Pat Collins.

Buzz Aldrin's 11-year-old son Andy told the Associated Press in July 1969 that "it was very exciting" when his dad landed on the moon.

But Mrs. Aldrin said she didn't want her son to follow in his father's footsteps.

"Oh Lord, I couldn't go through this twice," she told the AP.

If you've got another story about a woman who was instrumental to the Apollo missions, send this reporter a note: hbrueck@businessinsider.com