For decades, women’s place in the space industry was questioned. But, as Dr Elise Stephenson writes in this extract from her new book, Space XX: Gender, Power and the New Space Race, the science tells a different story, including evidence there are potential advantages of having all-female space crews.
Concerns around women’s suitability for space – backed by, at times, a bit of good old-fashioned sexism and pseudoscience – have long dominated men’s minds.
Journalist Amy Teitel writes for Popular Science that a report was published after Dr Lovelace’s Mercury 13 Women in Space Program (which ran over 1959–60) was terminated.
The 1964 report questioned whether a menstrual cycle would affect a woman’s ability to work in space, with the authors writing that the ‘intricacies of matching a temperamental psychophysiologic human and the complicated machine … are many and, obviously, both need to be ready at the same time’.
In other words, it would be difficult to sync a women’s cycle and spaceflight to avoid the ‘temperamentally dangerous’ premenstrual syndrome.
The authors further write, ‘it seems doubtful that women will be in demand for space roles in the very near future’, reinforcing a common perception that women were neither suitable for nor desired such roles.
Fast-forward several years and I am glad to share reports that women can and do menstruate safely in space, although there are also many options around for suppressing menstruation during spaceflight, too.
We have other insights from studies conducted over the years since the 1960s. For instance, while space travel is associated with hearing deterioration and even total hearing loss, hearing tests in crew members showed gender differences in hearing thresholds, with women presenting better results.
Another study looked at the immune responses of the SpaceX Inspiration4 mission crew (4 people) in 2021. It sought to understand how the immune system responds to and recovers from spaceflight. The authors found that male immune systems were more affected by spaceflight for almost all cell types and metrics. Although all participants experienced dysregulation of immune function, gene regulatory and immune response is more sensitive in men.
The authors conclude that their results have implications for crew selection, advocating for ‘(e.g., more females) for high-altitude, lunar, and deep space missions’.
A ringing endorsement? But for ‘e.g.’, I’ll take it.
A recent study on body size finds that there are ‘a number of potential advantages of all-female crews during future human space exploration missions’.
The research highlights how the female form tends to be more efficient in space, estimating that in comparison to a four-person all-male space mission of identical length, an all-female crew would deliver savings of 1695 kilograms in food and 2.3 cubic metres in physical space, equivalent to a saving of approximately 4 per cent of the total habitable volume of a Gateway module (one of NASA’s modules proposed for the lunar orbit space station, which is about 60 cubic metres).
This is highly significant operationally. Women also lose 29 per cent less water through sweat during a single aerobic countermeasure exercise (exercises critical to prepare for the physiological effects of being weightless), requiring less water to rehydrate.
According to journalist Justin Jackson, who reported on the research, savings from an all-female space crew could total around $158 million per mission.
One long-time space expert I spoke with during my research, a woman with a disability, told me that she attended a talk in the 1990s at the UK International Space School on who would be the best sort of astronaut to send to Mars:
[The speaker’s] ultimate conclusion was that the best person as an astronaut to go to Mars would actually be, pardon me putting it in these terms, but a legless female dwarf. In other words, you don’t need your legs while you’re going to Mars weightless … Women, as we know from many years of research, by and large cope much better than men, in general terms, with the isolation of space, in a sense with being perhaps cut off. Also, apparently, we cope better with weight-lessness as well. If you’re small, you use up less resources generally. All these things are in your favour. When you get to Mars, you’d only be able to operate the base station, so you’d have to have somebody with legs to go into the walk. But I thought it was a really interesting talk. And in a lot of ways, he’s right. I mean, you could send me to the space station tomorrow. And I would do perfectly fine.
Other research suggests mixed-gender crews in space and analogous environments are more efficient, cohesive and have better overall group dynamics.
Yet gender differences are also reported to lead to some crew tensions. For instance, studies conducted at Antarctic stations show that women are seen as outsiders and need to prove their competence in order to be accepted by male colleagues. This has real impacts on women’s self-esteem, influence, safety and leadership.
Additionally, in the Mars Desert Research Station, gender influences status in crews.
In other words, while gender is a poor predictor of Extravehicular Activity (EVA: activity by an astronaut in outer space, outside a spacecraft) by itself, when you control for other factors, being a woman is associated with less frequent EVA opportunities than men (e.g. getting out of the spacecraft to perform spacewalks, data collection).
This constrains opportunities for female crew members, contributing to the persistence of gender inequal-ities in space training environments by obstructing women’s competence and, perhaps, assuming inadequacy.
There are also plenty of aspects of work in space where no sex-based differences have yet been observed. This includes in areas like alertness, self-ratings of workload, stress, tiredness and sleep quality.
Scholars note that the likelihood of sex differences in affective disorders like depression or anxiety are also reduced due to the rigorous astronaut screening process.
Many also note that sex-specific medical needs can be readily managed through preventative measures, countermeasures and the inclusion of appropriate medical capabilities, although deep space missions may not have resupply possibilities and remain a greater challenge.
Ultimately, the role of sex and gender in spaceflight is still poorly understood because of the overrepresentation of men as astronauts.
Common countermeasures, like exercise routines, hormone therapy and pharmacological interventions to prevent vertigo and motion sickness, have not yet been adequately disaggregated for gender – meaning we don’t have the best idea of what could work to minimise harms and maximise any upsides of various elements of spaceflight.
Even though we have some indicative findings, there remains a lack of thorough research on female astronauts’ reproductive changes during or after space missions – with data on human female reproduction and the impacts of spaceflight on all reproductive stages limited.
As one expert I spoke with noted, ‘reproductive health? It’s almost a taboo … It’s not studied well either.’
Limited understanding of topics like endometriosis or landing and post-flight conditions remain opportunities for future research.
The lack of data on female astronauts has slowed progress, yet researchers highlight that with the growing number of women in space, this gap is expected to narrow over time.
Part of the benefit of making spaceflight more accessible to women is that it is essential to furthering the empirical research.
Increased female participation in space missions and analogous Earth-based studies is crucial to be able to address sex- and gender-based disparities in spaceflight, enabling the development of measures like enhanced radiation protection and tailored nutrition, which can improve astronauts’ health and performance.
Dr Elise Stephenson’s new book is available for order here.