We Need More Women in Space
​Image: ​Madeline Masarik

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We Need More Women in Space

New reports shed light on how spaceflight affects men and women differently.

​We need more women in space.

That's the first recommendation to come out of a series of review studies led by NASA and the US National Space Biomedical Research Institute (NSBRI) that look at sex and gender differences when it comes to how humans adapt to spaceflight.

In some fundamental ways, men and women are different. Diseases occur at different rates in male and female populations, and male and female bodies respond differently to certain situations. It's no surprise that this should also be true in the rather extreme environment of space. Out there, knowing these differences is vital in order to develop the best prevention strategies, treatments, and rehabilitation techniques.

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Six articles published in t​his month's Journal of Women's Health reveal how male and female astronauts differ: Women, for instance, are more likely to suffer orthostatic​ hypotension, a cardiovascular issue that leads to feeling faint. Preliminary findings suggest that men, however, are more likely to suffer more severe cases of visual impairme​nt due to intracranial pressure (VIIP) syndrome, which affects the eyes and is currently recognised by NASA as a leading spa​ceflight-related health risk.

And while women astronauts more frequently experience "space m​otion sickness"—the spaceflight equivalent of travel sickness—on entry to the International Space Station, men are more likely to get nauseous on their return to Earth.

"When the body goes into space it adapts very quickly, very dramatically, and the differences we see between men and women can have significant impact," Saralyn Mark, a senior medical adviser at NASA and an author on the report, told me in a phone interview alongside co-author Bette Siegel of the Human Exploration and Operations Mission Directorate.

Siegel added that these differences are even more important given plans for long-duration missions to deep space, and even Mars, that will include both male and female astronauts. "Therefore, we need to make sure that we're studying women so that when we do develop these kind of measures, they work for both and men and women to protect their health and enhance their performance in space."

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Siegel said the new research is the first time all the published and unpublished data has been reviewed—"so it's like a line in the sand of where we are currently." But out of an already small potential sample set of 535 humans who have ever travelled in space, only 58 are women.

In some cases, it's possible to look at differences between the sexes on Earth to get an idea of the risks spaceflight could pose, but that's not always useful. For example, women are about four times more likely than men to get osteoporosis on Earth, but there's no clear evidence for a sex difference in musculoskeletal resp​onse to spaceflight.

We also know that women are more resistant to infection on Earth, and respond differently once they do get an infection. "But whether these immune system changes also play a significant role when you're put in microgravity and a radiation environment, that still needs to be looked at further," said Mark.

And while women are generally around twice as likely as men to experience an affective disorder like depression on Earth, that doesn't seem to be the case among astronauts—something Mark said could be down to the industry's rigorous recruitment and training process.

You want to be prepared if half of your astronauts are going to feel faint when they step onto Mars

It's therefore important to study women and men in the actual space environment too, to see how their requirements change. You want to have measures in place if half of your astronauts are going to feel faint when they step out of their space vehicle and onto Mars.

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But even with the data available, sex differences haven't always been considered. In earlier data, the sex distribution of subjects isn't always clear and, frustratingly, some journal editors and reviewers don't always publish demographic information. Mark said the recent move by the National Institutes of Health to push for the inclusion of bo​th sexes in preclinical research as well as later-stage trials would likely help.

"I think once you begin to look at the world through a sex and gender lens you see the complexity as well as perhaps even the simplicity of your questions," she said. "It really adds a phenomenal dimension."

And the best way of getting more accurate findings on the differences between men and women would obviously be to have more women in space. It's promising that NASA chose four men and four women in its latest crew sel​ection.

Even then, of course, numbers will be low and the researchers warned against over-generalising based on sex and gender—a lot of other factors can account for variations between individuals. But you don't necessarily need statistically significant results to make useful observations. In the case of VIIP syndrome, 82 percent of male astronauts and 62 percent of female astronauts were affected, but those numbers were less relevant than another observed trend: the worst cases were only really seen in men.

It's not a battle of the sexes, however; Mark and Siegel were keen to emphasise that any differences shouldn't be used to discriminate. We don't want all-male or all-female space teams.

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"It really should be used as a variable that we look at so we develop the best kind of measures, the best modalities, to treat men and women," said Mark.

There's an ethical element too: At the moment, for instance, NASA sets a lower radiation exposure limit for women than for men, as women's bodies are more sensitive to radiation (having breasts and female sex organs ups your risk of cancer). Former NASA Chief Astronaut Peggy Whitson h​as suggested that this limit on women's travel could be discriminatory, denying women opportunities.

Mark and Siegel said it's something currently under discussion, especially in regard to longer trips such as to Mars, which could throw those exposure limits out the window anyway.

Meanwhile, it's pretty pointless arguing whether male or female astronauts are in some way physically "better," especially as we know comparatively so little about women's responses to the space environment. That's why selecting more female astronauts is a priority for the researchers on this report.

And women bring at least one more advantage to the prospect of long-distance space travel: They eat​ less.

xx is a column about occurrences in the world of tech, science, and the internet that have to do with women. It covers the good, the bad, and the otherwise interesting gender developments in the Motherboard world.