An anonymous reader quotes a report from NBC News: Astronauts making a years-long voyage to Mars may get bombarded with enough cosmic radiation to seriously damage their brains, researchers reported Monday. The damage might be bad enough to affect memory and, worse, might heighten anxiety, the team at the University of California Irvine said. It's the second study the team has done to show that cosmic radiation causes permanent, and likely untreatable, brain damage. While their experiments involve mice, the brain structures that are damaged are similar, they write in the Nature journal Scientific Reports. NASA knows that astronauts risk physical damage from the radiation encountered in space. Earth is enveloped in a large, protective sheath called the magnetosphere, which deflects a lot of the ionizing radioactive particles that speed through space. Teams aboard the International Space Station are inside that envelope. But moon travelers were not, and this summer a study showed the cosmic radiation may have damaged the hearts of many of the Apollo program astronauts. A trip to Mars would expose astronauts to even more radiation -- enough to cause cancer, for sure, and now this research suggests brain damage, as well. They bombarded mice with the same type of radiation that would be encountered in space, and then looked at what happened to their brains. It did not look good. The changes were seen in the connections between brain cells and in the cells, as well. "Exposure to these particles can lead to a range of potential central nervous system complications that can occur during and persist long after actual space travel -- such as various performance decrements, memory deficits, anxiety, depression and impaired decision-making. Many of these adverse consequences to cognition may continue and progress throughout life."