Space travel, you may have heard, is hard. Hard on the brain, to design ways to slip the surly bonds of Earth in the first place, but also hard on the body, which needs to withstand conditions it was never designed for. If NASA’s serious about sending humans back to the moon and on to Mars, we’ll need to get a much better grasp on how spaceflight affects the human body. And instead of simply flying more and more people to space to find out all the potential effects, scientists have turned to