In order to be selected by NASA to go to space, an astronaut must be in almost perfect health, free of any known chronic conditions, and able to undergo rigorous physical training over the course of years.
But even though astronauts may be at the peak of fitness, they’re only human. Despite NASA’s excellent screening practices, no person is immune from medical issues. And even the most extensive amounts of preparation and training can’t prevent every single type of medical emergency that could occur in lower Earth orbit.
Dorit Donoviel is deputy chief scientist of the National Space Biomedical Research Institute (NSBRI), a NASA-funded group of institutions looking at all the health-related risks that can occur in the big wide vacuum. “Anything that can happen to you and me on Earth can happen in space,” she tells Popular Science. “You can have a kidney stone, a headache that doesn’t resolve, or elevated pressure on the brain. You can even have a heart attack. NASA needs to be worried about all the medical repercussions of an unresolved medical problem.”