Being a deep-space astronaut may be bad for the brain, according to a new research study.

Scientists say spending years at a time in space could make astronauts more vulnerable to developing Alzheimer’s disease.

This would happen because of the long-term exposure to cosmic radiation, which spacecraft can’t entirely block out. To do so, said the study’s senior co-author Dr. M. Kerry O'Banion, “one would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”

Cosmic radiation is unlike anything on Earth, with the closest comparison being the effects of a nuclear accident, he said.

Scientists have long believed that such exposure, outside of Earth’s atmosphere, can lead to cardiovascular disease, cancer, and cataracts, with longer-term exposure endangering the central nervous and gastrointestinal systems, lungs and eyes.

The Alzheimer’s study could have implications for the National Aeronautics and Space Administration’s (NASA) plans to send astronauts on missions to a far away asteroid or Mars. Going to Mars and returning to Earth would take about three years using current technology.

Researchers at the NASA Space Radiation Laboratory came to their conclusion after spending eight years studying mice that were genetically engineered to be predisposed to Alzheimer's disease, while exposing them to cosmic radiation. It was the first such study ever conducted.

-Noel Brinkerhoff, Danny Biederman

To Learn More:

Cosmic Radiation Could Cause Alzheimer's in Mars Astronauts (By Susan Donaldson James, ABC News)

Galactic Cosmic Radiation Leads to Cognitive Impairment and Increased Aβ Plaque Accumulation in a Mouse Model of Alzheimer’s Disease (by Jonathan D. Cherry, Bin Liu, Jeffrey L. Frost, Cynthia A. Lemere, Jacqueline P. Williams, John A. Olschowka, and M. Kerry O’Banion, PLoS ONE)

Six Astronauts to Begin 520-Day Mock Flight to Mars (by Noel Brinkerhoff, AllGov)

Losing Your Memory? Stop Googling, Turn Off Your GPS and Stop Watching Violence on TV (by Noel Brinkerhoff, AllGov)