In April, Netflix debuted Mercury 13, a documentary about a trailblazing group of 13 women in the 1960s who could have been the first US female astronauts, if their training program hadn’t been cancelled. The doc is a touching portrait of the women pilots, but it leaves some questions unanswered.

The Mercury 13 program was not officially run by NASA. It was created by NASA physician William Randolph Lovelace, who developed the physical and psychological tests used to select NASA’s first seven male astronauts for Project Mercury. The women completed physical and psychological tests, but before they could complete the training, the privately funded program was cancelled. Why did that happen?

In the Netflix documentary, one of the female pilots says NASA had “no need for women astronauts.” The space agency “didn’t want this program, pure and simple,” says Jackie Lovelace Johnson, Lovelace’s daughter. The documentary doesn’t provide NASA’s take, or feature interviews with historians. Directors David Sington and Heather Walsh tell the story through sit-down interviews with some of the Mercury 13 women and their relatives. The doc also leaves unclear why exactly one of the women, famous pilot Jacqueline Cochran, eventually testified against the program when the case was brought before Congress in 1962.

To answer these questions, and get more context, I spoke with Margaret Weitekamp, a historian at the Smithsonian National Air and Space Museum, and author of the book Right Stuff, Wrong Sex: America’s First Women in Space Program. Weitekamp hadn’t seen the documentary when I talked to her, but she did tell me right away that the women shouldn’t be called the Mercury 13. “It is ahistorical and misleading,” she told me.

The following interview has been edited for brevity and clarity.

Why shouldn’t the women be called the Mercury 13?

The term was invented as a catchy title in the 1990s by a television producer, but I found that it confuses the history by suggesting that the women were a part of a NASA program attached to Project Mercury, or that they gathered as a group in some way in the 1960s. In fact, the group never gathered until the 1990s, by which time two of the 13 had already died. I think it’s even more remarkable that these talented women pilots did so well on early medical testing, alone or in pairs, and not with the benefit of going through as a group. So I tend to talk about the Lovelace’s Woman in Space Program, which is what Dr. Lovelace called it, or about the First Lady Astronaut Trainees, after the way Jerrie Cobb [one of the pilots] referred to their group in her letters.

Why were there no women astronauts at the time?

The decision to choose the first astronaut candidates from the ranks of military-trained jet test pilots meant they were drawing from a candidate pool that could only include men. Women had been banned from military flying after the end of the Women Airforce Service Pilots (WASP) in 1944. That was a civilian program of over a thousand women that was run during the Second World War as a way of relieving male pilots for combat roles during the war, by having well-trained women pilots take over domestic flying, ferrying aircraft, towing targets, training, transporting aircraft from place to place. The highly successful program was disbanded in 1944 as the war was wrapping up. As the opportunities for flying in combat were shrinking, at the same time, there were more male pilots available for flying roles. And so they ended the Women Airforce Service Pilots and gave those jobs back to male pilots. That, for women in aviation, is a significant change because it’s really only at the end of the Second World War and into the 1950s that jet planes come into use first in the military. So women had very little access to that new technology.

How did the Lovelace program start?

Lovelace was a medical doctor who had done the physical testing for NASA in the selection of the Mercury astronauts, who were announced in April of 1959. Before any human being had flown into space, he was very curious about what would be coming. He was envisioning huge orbiting space stations that would be able to do reconnaissance, that would do science research. And he’s thinking that if you’re going to have a large orbiting space station with dozens of people on it, that would normally — in that kind of military setting — include women as secretaries, telephone operators, laboratory assistants, nurses. So he was very curious about whether women could physically withstand the forces that would be necessary for them to participate in spaceflight. He ran a privately funded project at his foundation in Albuquerque, New Mexico, and invited 25 different women pilots to come out and take the same tests he had given with his team to the Project Mercury candidates, to see how women would do.

The Netflix documentary makes it seem as if the program was secret. Is that true? NASA didn’t know about it at all?

The program was privately run and privately financed, which meant that at least initially, not many people knew about it. But pretty quickly, it was relatively well-publicized. There were articles about Jerrie Cobb in LIFE magazine. There was an article about the project in McCall’s, a women’s magazine. It appeared on the cover of Parade magazine. So it may not have been very well-known, but it certainly was not a secret program.

The documentary says the women performed better than the men. Is that accurate?

Yes, the data show that is true. There was an Army pulmonologist, Kathy Ryan, who a few years ago did a very good piece in a physiology journal where she looked back at the test results that had been recorded for the Lovelace women as well as the Mercury astronaut candidates, and showed that especially in cardiopulmonary function, the women on average did better than the men. And we know that from the 1950s on, statistically, women did better in isolation tests and in sensory-deprivation tests than men did. That had been shown in British studies, Canadian studies, American studies. The idea that women could be included in spaceflight had been a popular discussion both in medical circles and in general popular culture in the late 1950s.

Why was Lovelace’s Woman in Space Program cancelled? Did NASA shut it down?

NASA didn’t start it. NASA didn’t shut it down. What happened was, the privately funded tests Lovelace did got canceled, because he had run through all the tests he could do at his own private facilities. He was hoping to start a new phase of tests that would use the Navy medical facilities in Pensacola, Florida. And there was no requirement for such tests from the military, in a military sense of a requirement, where you create a program to do things and then allocate funds to do that. There was no military program or government program that was going to use women astronauts, and therefore they withdrew the favor of being able to use the facilities. In my opinion, what really ended the chance that at this early moment in the human spaceflight program, there might have been some experimentation and the inclusion of a woman, was Kennedy’s decision to go to the Moon.

How so?

On May 25th, 1961, Kennedy gets up before a joint session of Congress and says, “We will send a man to the Moon and return him safely to the Earth before the end of the decade.” And that policy decision about the next step in human spaceflight was made very early. The United States had only had one human spaceflight, the suborbital flight of Alan Shepard, only 15 minutes of practical human spaceflight experience, and Kennedy is saying they’re gonna go a quarter of a million miles to the Moon and back, and land and walk around. That really streamlines the decisions being made within NASA about the directions for human spaceflight.

The moment when someone might have been able to be persuaded to do the experiments of seeing how a woman would fare flying in space really ends with that decision to streamline the space program toward the Moon landing. They had one goal that didn’t include the social experimentation of flying a woman, and they were then legitimately concerned about the political ramifications of having any flights that seemed off of the lunar focus. Certainly they worried a lot about, if anything happened to a woman on a flight, whether that would end all human spaceflight programs.

In the Netflix documentary, some interviewees say NASA didn’t want the program, or to see women in space at all. Is that accurate? Does it overstate the conspiratorial image?

I think the story gets told in two different ways: as a door shut in the face of these women, or a door briefly opened for them. And I think in the larger history on women’s accomplishments that require physicality and moving into traditionally masculine realms, you see a lot of beginnings of programs, or beginnings of opportunities for women, and then that rolls back, and then it comes back again 15 years later. I’ve been fascinated by this story of a privately funded women’s astronaut testing project, because it was a moment when some people, who were highly recognized and had great reputations in the medical community, took women seriously as medical subjects in an era when that just wasn’t done.

Most pharmaceutical research, until very recently, excluded women. Most medical experiments would have excluded women, because the medical profession worried that women’s monthly cycles made them unreliable test subjects. For the doctor who NASA trusted with its physical testing to be looking at women not as flawed men, but perhaps as astronaut candidates who could even be more physically suitable than men were — that’s a remarkable opening of a door in the very early 1960s. There just wasn’t the support yet that would have helped them keep it open. The women’s organizations that might have advocated for these women simply didn’t exist yet.

Who was Jacqueline Cochran, and what role did she play in the program?

Cochran is a fascinating historical character, in that she was great friends with Randy Lovelace. She was a contemporary pilot of Amelia Earhart, she was a record-setting pilot in her own right, and married to one of the richest men in America, Floyd Odlum. So she had access to great resources. She had actually been the head of the Women Airforce Service Pilots during the Second World War. So she is the funder for Lovelace’s Woman in Space Program. At the end, she actually testified against the women at the house subcommittee hearing.

Why?

It’s not written down anywhere. She never wrote down exactly, “This is why I did that.” My conclusion as a historian is that she hoped that the program could be revived in a different form under NASA’s auspices, and that she would be the head of that, the way she had been the head of the Women Airforce Service Pilots during the Second World War. I think as a politically astute person, she saw that the project as done by Lovelace was not going to go forward in any real way in that moment in the early 1960s, and she worked behind the scenes throughout the 1960s to try to influence NASA to start a women’s program. She did an extended term as a consultant to the agency, and was very pleased with the association with such a powerful agency.

Why is it important to know about these trailblazing women?

The history of women’s ongoing struggle for recognition — intellectually, politically, socially, culturally — is rooted in the understanding of women’s capabilities. And this is an important first look at women as physically capable. I think that when we look at the ways women are still struggling to be recognized, in boardrooms or in the Supreme Court, or the White House, or in Congress, there’s a slowly evolving story of women struggling to have their capabilities recognized. And this is an important early episode where someone took women and their bodies seriously, as capable.