What if we could get rid of lengthy waitlists for organ transplants? Well, imagine 3-D printing a kidney from your own stem cells. That would reduce the chances your body rejects it. That’s the sort of groundbreaking medical research astronauts are conducting aboard the International Space Station. Other research includes understanding the stress spaceflight places on not just the body, but also the mind. There’s a plethora of human factors to consider as humanity prepares to embark on deep space missions. What we learn from spaceflight medicine could also transform lives here on Earth. Dr. J.D. Polk, NASA’s chief health and medical officer, tells us what’s on the horizon in space medicine.