Kowal believes that gender isn’t a big factor in determining whether or not someone’s going to be a good astronaut. “Being an astronaut is about curiosity, expertise, excellence and taking joy in the exploration of space. That said, there are some physiological differences that might make women better suited for space travel. During the Mercury program, Dr. Lovelace did a series of studies with women in which he ran them through the same tests as the Mercury astronauts. A higher ratio of women passed the tests than men. They tolerated higher g-forces, did better on stress testing and were more cardiovascularly fit than the men. In modern parlance, these are the Mercury 13, although at the time they called themselves the First Lady Astronaut Trainees.”

“Women use fewer calories and consume less oxygen than men.” she continued. “We typically weigh less. All of which are important considerations when trying to get someone out of the gravity well and into space.”