What happens to female bodies in space?

Going into space changes people, and not just in a ‘perspective shifting, the earth is so tiny’ way: the lack of gravity in space affects bone density; makes people literally taller, and affects a host of organs, from your heart to your eyes. However, most of the data on what happens to the body in microgravity comes from studying men, as the majority of astronauts have been male. Now, a new experiment has been launched by the European Space Agency, ESA, to look at how female bodies are affected. Eva Higginbotham spoke with ESA scientist Angelique Van Ombergen ...

Angelique - We have started a dry immersion study with 20 females and the dry immersion is the sort of model in which we can simulate weightlessness or microgravity, which allows us to do some research that can help us to prepare human space flight. In essence, the idea is that you put people in, let's say a bathtub, if you want to imagine it like that, and you leave them there for five days. The fact that it's a dry immersion study means that, in essence, their skin is not in contact with the water. So they stay dry, but they are immersed in the water for five days. This induces changes that are very similar to what we see in astronauts, and that can help us to better prepare human spaceflight and to get a better understanding of these changes.

Eva - Five days in a bathtub just does not sound very comfortable, so how did you go about recruiting people for this study?

Angelique - It's not easy to find people to do it, especially now because we're only targeting female subjects. So, they can read the book, they can be on the laptop, but of course, they at all cases need to be in the bathtub. They also can only use a pillow to support their heads when they're eating, but for anything else, they're just lying. And, of course, they can hold something up, but yes, it's not going to be the most comfortable thing.

Eva - Does the weightlessness bit come from the fact that they're in water. So they're kind of being held up by water. Is that how it's similar?

Angelique - Yes, exactly. So, you have the immersion in the water, which creates something that we call supportlessness. Because, normally, when you're sitting on a chair, for example, you're always supported in one way or the other - either it's your feet on the floor, or it's your bum on a chair, or when you're lying in the bed, it's your back. So there's always something supported. And, of course, in weightlessness, you do not have that unless you really touch something. The idea of having somebody in the water basically mimics that in a certain way. And we know that it also induces similar changes to what we see in astronauts.

Eva - And what makes you want to focus on female bodies in this experiment?

Angelique - The dry immersion model has already been used, mostly in Russia and also in France, but the subjects that they have included were always male subjects. So there is already quite some knowledge on how dry immersion induces bodily changes and physiological changes, but there is no data available on female subjects. So that's why we wanted to include 20 female subjects to, let's say, address some of the knowledge gaps that we still have, and to get a better understanding potentially on how males and females differ in these changes that we see.

Eva - And what changes do you see? What do you expect to happen to the body? And why might it be different in a female body than a male body?

Angelique - We know that there's a lot of differences between males and females. Sometimes these differences are quite small, sometimes these differences are bigger. So that really depends. And we know also that, in general, there are a lot of differences between individual people, so if you have Person A and Person B, there's going to be differences between them, even though they might be considered both in a normal range. We know that, for example, we have loss of bone density, we have loss of muscle mass, the immune system is challenged, we can have vision changes. From the data that we have from astronauts already, we know, for example, that female astronauts seem to be less susceptible to vision changes, just to name one example. Now we need to be sure that this is indeed the case. And if so, then we want to understand better why they might be more protected. It might be, for example, hormonal, it might be cardiovascular changes - there might be something different and we need to investigate it.

It might also be that we do not see it in females yet, just because we don't have enough female astronauts to test. This is an important distinction, of course, and we can only address that if we have sufficient female subjects to actually do the testing on. By this dry immersion study, and some other ground-based studies that we do, we really hope to address that knowledge gap. There's really a broad scope. And what we, of course, want to do is find the counter measures that are best in mitigating some of the unwanted effects of space flights. Potentially we will come to a situation where this might be individualised to a certain individual and then to a specific astronaut.