A new study has revealed that cosmic radiation sustained during journeys into deep space could cause subtle brain damage in astronauts, decreasing their ability to think, remember and react. The study, which comes while NASA is working on a manned mission to Mars, was published in the journal Science Advances on Friday.

The researchers found that long-term exposure to extremely powerful charged particles within cosmic rays that astronauts are exposed to during extended spaceflights could significantly damage their central nervous system, resulting in dementia-like cognitive impairments. The latest findings highlight serious implications for plans of manned forays into deep space.

“This is not positive news for astronauts deployed on a two- to three-year round trip to Mars,” Charles Limoli, a radiation oncologist at the University of California, Irvine, said in a statement. “Performance decrements, memory deficits, and loss of awareness and focus during spaceflight may affect mission-critical activities, and exposure to these particles may have long-term adverse consequences to cognition throughout life.”

As part of the study, mice were subjected to charged particle irradiation at the NASA Space Radiation Laboratory at Brookhaven National Laboratory in New York, before being sent back to Limoli six weeks later for analysis. After examining the mice, it was found that exposure to the charged particles resulted in brain inflammations, disrupting transmission of signals among neurons.

In addition, the mice also exhibited decreased performance in learning and memory tests. There was also a lack of curiosity in the rodents, making them sluggish in other experiments involving objects placed in a box with them, the study found.

According to Limoli, people would “without a doubt” face the same issues as the mice, putting any space mission at risk, especially if unanticipated situations arose during deep space flights, Reuters reported.

“I don’t think our findings preclude future space missions,” the Wall Street Journal quoted Limoli as saying. “But they suggest we need to come up with some engineering solutions.”