A trip to Mars could cause brain damage. Here's how NASA aims to protect astronauts.

During Scott Kelly’s year in space, the astronaut was zapped relentlessly by radiation — the equivalent of 10 chest X-rays a day for more than 11 months starting in March of 2015. The onslaught damaged Kelly’s DNA and affected his immune system while raising his risk for cancer. And Kelly was aboard the International Space Station, whose tight orbit around Earth lies within the magnetic field that surrounds our planet and blocks the most damaging forms of radiation.

Astronauts who travel to Mars or other destinations in deep space will leave Earth’s protective cocoon for months or years at a time. And a new NASA-funded study suggests that chronic exposure to radiation could harm astronauts’ minds as well as their bodies — potentially affecting space flyers’ moods and even their ability to think.

That could be a big deal.

“The nature of the radiation environment in space will not deter our efforts to travel to Mars, but it may be the single biggest obstacle humankind must resolve to travel beyond the Earth’s orbit,” the researchers wrote in the conclusion to their study, which was published Aug. 5 in the journal ENeuro.

Earth’s magnetic field guards the planet against solar radiation.Steele Hill / NASA

Dr. Munjal Acharya, a radiation oncologist at the University of California, Irvine, and the study’s lead author, said radiation exposure “affects cognitive function and behavior at the cellular level,” adding that the exposure might make it hard for astronauts to respond effectively to unforeseen circumstances or stressful situations.

The research suggests that at least one in five astronauts sent to Mars would return with severe deficits in cognitive function, he said.

Stressed-out rodents

For the study — the first to simulate the radiation astronauts would be subjected to on a mission to Mars — Acharya and his collaborators exposed 40 mice to radiation for six months and then tested the animals’ memory and behavior.

One test showed that radiation-exposed mice were less able than control animals to notice subtle changes in their environment. Another revealed that the radiation-exposed mice were so anxious that they “froze” in situations that caused no anxiety in the control animals.

“That fear was so strong in them that they were still freezing” in anticipation of an electric jolt that the researchers had stopped delivering, Acharya said, adding that the radiation seemed to make it hard for the mice to learn and adapt by weakening connections between different regions of the animals’ brains.

source: nbcnews.com