When groundbreaking astronaut Sally Ride became the first American woman in space in 1983, she received plenty of congratulations. But one of the most meaningful nods to her accomplishment was not from a NASA official or a head of state; it was from an attorney named Linda Halpern. When she heard that Ride had made it into space, she wrote to her to thank her for fulfilling her childhood dream of space flight.

Halpern could have faded into the jumble of congratulatory letters or cards had she not enclosed another letter in her correspondence to Ride: a response she herself had been given when, as an elementary schooler in 1962, she wrote to ask how she could go to space. The response was terse, typewritten. “Your willingness to serve your country as a volunteer is commendable,” responded a NASA official. “However, we have no present plans to employ women on space flights because of the degree of scientific and flight training, and the physical characteristics, which are required.”

Ride kept the letter for the rest of her life. But though her pioneering career smashed the space barrier for women, it wasn’t without its own moments of sexism. And if not for a failed attempt to send American women to space, Ride may never have stepped foot on a space shuttle in the first place.

Though Ride’s 1983 flight on the Challenger space shuttle marked the first time an American woman had been in space, she wasn’t the first woman. Valentina Tereshkova, a Russian cosmonaut who spent three days in space two decades earlier, was the world’s first, though the USSR took nearly 20 more years to send another woman to space.

The United States was even less eager to work with women astronauts: When it selected its first astronauts, it required all candidates to have engineering degrees and to have graduated from jet pilot testing programs in the military. Since the military didn’t allow women to be test pilots, applicants were, by default, men.

In the early 1960s, a privately funded project called the Woman in Space Program challenged that status quo. When two male Air Force researchers wondered if women might better fit in small, cramped spacecraft, they decided to test the premise. The experiment evolved into a program that invited elite female pilots to undergo NASA’s testing regimen. The project was funded by Jacqueline Cochran, herself an elite pilot. Eventually, 13 women were identified, trained and passed NASA’s barrage of selection tests.

However, the program was suddenly canceled in 1962. When the House of Representatives held public hearings to find out why, NASA cited rules that excluded women. Astronauts, including John Glenn, testified about the cancellation. “It is just a fact,” Glenn testified. “The men go off and fight the wars and fly the airplanes….The fact that women are not in this field is a fact of our social order. It may be undesirable.” Though 13 women were qualified to become astronauts, they never stepped foot on a spacecraft.

When Ride and five other women were chosen to join NASA’s astronaut class of 1978, they were the first ever officially welcomed by the agency. By that time, Ride was an accomplished physicist. But though she didn’t have to worry about her program being nixed, she still faced gender bias at work.

Though Ride later recalled NASA’s attempts to welcome her and her fellow women into her ranks, she admitted that some of the older astronauts, who had never worked with women, had to adjust to the idea of a woman coworker. “The astronauts who’d been around for a while were not all as comfortable and didn’t quite know how to react,” she recalled in a 2002 oral history. “But, they were just fine and didn’t give us a hard time at all.”

Ride was also entering an agency that didn’t always know how to adjust to the presence of women. Ride recalls NASA engineers asking her to help them develop a makeup kit, which they assumed women would want in space. They also struggled to figure out how to accommodate a menstruating astronaut, remembered Ride, even suggesting women take 100 tampons with them to space for a one-week flight.

“They had never thought about what just kind of personal equipment a female astronaut would take,” Ride said. “They knew that a man might want a shaving kit, but they didn’t know what a woman would carry. Most of these were male engineers, so this was totally new and different to them.”

NASA engineers eventually adapted to the idea of a woman aboard a spacecraft, but the press treated Ride’s upcoming flight as if it were an insurmountable technical challenge. She was asked if she cried under pressure and whether the flight would affect her reproductive organs. “Everybody wanted to know about what kind of makeup I was taking up,” she told Gloria Steinem in a 1983 interview. “They didn’t care about how well-prepared I was to operate the arm or deploy communications satellites.”

Ride’s first flight was a rousing success, and eventually press chatter about her gender died down. She became one of NASA’s most well-known and well-respected astronauts, and not just because of her gender. Not only did Ride serve NASA in space on two flights, but she was appointed to help investigate the Challenger and Columbia space shuttle disasters. She also helped with NASA’s strategic plan and, after retiring from the agency, was a physics professor, science communicator and author.

Ride died in 2012, and five years later NASA named its most recent astronaut class—50 percent of whom are women. That’s exactly how she would have wanted it. But perhaps the best tribute to Ride will be when gender parity is so common as to attract little or no notice. As she said in 2002, “It’ll be a wonderful day when this isn’t news.”