MRK: Yes. We know this because of a series of experiments conducted by Dr. W. Randolph Lovelace II with women who called themselves the “First Lady Astronaut Trainees.” The Air Force started the program, then worried that people might think they were actually going to send a woman into space. So they passed it off to Dr. Lovelace’s clinic. He ran a group of women pilots through the same tests he gave the male Mercury astronauts. Among other things, he found that they handled stress testing significantly better than men.

JB: This happened in 1960, and yet there is a famous 1962 NASA letter written to a young girl who was interested in becoming an astronaut, in which the agency explains that they have “no present plans to employ women on spaceflights” because of the training and “physical characteristics” required.

MRK: Well, by that point, they realized that they wouldn’t need receptionists and secretaries in space. Seriously. That was one of the reasons for the support of the initial testing.

JB: How much better did those women actually handle the stress?

MRK: Let’s compare John Glenn, the first American to orbit the Earth, with Jerrie Cobb, the first of the First Lady Astronaut Trainees. Glenn’s stress testing consisted of sitting in a dark room for three hours. There was a desk with some paper. He wrote poetry. Cobb and the other women went into a sensory deprivation tank. It was thought that six hours in the tank would induce hallucinations. Cobb was in there for 9 hours and 40 minutes when it was finally ended by the staff. But she didn’t write any poetry so … you know. One of the women in the FLATs was a mother of eight, and I always imagine her feeling like this was a vacation.

As a side note: For years, the Air Force thought women could not fly jets, because their ability to tolerate the high-gravity forces of acceleration seemed to be lower. It turns out the G-suits were built for male bodies and didn’t make contact in the right places for women. When they got suits that fit, miraculously, they performed as well.