Importantly, the effects are long-lasting. Untreated mice showed memory problems about three months after their exposure, but those who received the drug soon after exposure demonstrated healthy behavior. That's crucial when trips to Mars will include months of deep space flight and prolonged stays on a relatively unprotected planet.

The medicine might be useful sooner than you think. There are already similar compounds in use for cancer treatment trials, so it wouldn't take a huge leap to use this anti-radiation medicine in the real world. And it wouldn't just be useful for astronauts, either. It could help prevent cognitive issues after cancer radiation therapy, or alleviate the effects of diseases like Alzheimer's.