Are We Close To Making Our Home Away From Earth?

Our exploration of the cosmos is hampered by our bodies and minds, which struggle in space. So could we ever overcome our Biology and settle among the stars?

- Dr Lewis Dartnell

You might have thought from watching videos of astronauts aboard the International Space Station (ISS) that spaceships were pretty benign environments. Floating around in microgravity looks like a lot of fun, and, as you’re isolated from the rest of the human population, you’re effectively quarantined against catching flu or any other transmissible disease. But, in fact, space is pretty harmful to the human body. We evolved as social animals under the conditions on Earth, and travelling beyond the planet has a number of negative effects on the body and mind.

So what are the main risks encountered by spacefarers, and what does the latest research have to say about how to solve these problems for long-duration missions in the future?

[ GRAVITY ]

Freefalling around the Earth in orbit, or coasting through interplanetary space on your way to Mars, gives you the sensation of weightlessness. You’re still moving under gravity, but it doesn’t load your body, and this has a whole host of knock-on effects. For example, your inner ear can no longer help you orientate yourself, and the redistribution of bodily fluids causes your face to puff up and your eyeballs to distort.

But the long-term effects are more concerning. Without the loading of gravity, your skeleton loses calcium and becomes brittle (like with osteoporosis). Your muscles, especially those involved in supporting your spine and holding you upright, deteriorate and shrink. Plus, your heart becomes weaker when it doesn’t have to pump blood upwards. While you remain in a weightless environment, this isn’t too much of a problem – and, in some senses, your body is being adaptive in remodelling itself to life without gravity – but it can be hugely debilitating or dangerous when you return to the surface of the Earth or any other planet.