Many things would be difficult about conducting a manned mission to Mars, from designing a spacecraft that could make the 34-million-mile journey, to stocking and fueling it, to keeping its astronauts from getting flabby.

Researchers shed light on another potential hurdle: figuring out a way to protect travelers' brains from the damaging effects of cosmic rays in outer space. When University of California, Irvine, neuroscientist Charles Limoli and colleagues exposed mice to radiation similar to that astronauts would encounter far beyond Earth, the animals experienced changes in their brains that impaired their performance on tests of learning and memory, the team reported in the journal Science Advances.

The researchers' results suggested that astronauts could suffer cognitive impairment during an extended journey. "Over the course of a two- to three-year mission, the damage would accumulate," Limoli said. "To mitigate it, we need to understand it."

Los Angeles Times