Floating weightlessly in orbit looks like the ultimate freedom, but the human body evolved under gravity’s constant pull, and taking that pull away does strange and serious things to it. This episode explores what actually happens to an astronaut’s body in space.

You’ll come away understanding why astronauts lose bone and muscle, why their body fluids shift and their faces puff up, the hidden danger of space radiation, and why keeping humans healthy is one of the biggest hurdles to reaching Mars.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: NASA – “Human Research Program” and “The Human Body in Space”; ESA – astronaut health pages; Kelly & Dean, Endurance.