Kidneys are exceptionally responsive and adaptable—but these traits can work against them. When microgravity shifts the body’s distribution of internal fluids, kidney tubules tend to shrink; this action hinders the organ’s ability to properly filter calcium and salts, increasing the risk of kidney stones and other health issues. And diminished tubules are more vulnerable to high-energy cosmic rays. “There’s an unholy alliance between microgravity and galactic radiation,” says study lead author Keith Siew, a kidney physiologist at University College London.
This is wild. Not something I’d ever expect to be an issue. Cool that we’re studying it.