US researchers draw that conclusion in the journal Scientific Reports. They rely on experiments with rodents.
The researchers suggested to expose rodents to a stream charged particles, and looked at what that did long-term with the brain of rodents. Six months after exposure, the researchers found more inflammation and damage to neurons in the brain.
They also found evidence that brain cells were less able to exchange signals, something came in tests that were designed to test memory and learning skills of the animals.
Also to be the influence of radiation turned on a psychological process, which is called fear extinction. During this process, the brain suppresses previous unpleasant and stressful associations.
An example: you are swimming and you get into trouble. You nearly drown. Fear extinction causes the anxiety you felt at that moment, is suppressed, so you eventually can resuming enjoying your swim.
Exposed rodents this process proved to be affected by radiation. “Abnormalities in fear extinction can make you more susceptible to fear,” said researcher Charles Limoli. “And that can be problematic for a three-year journey to Mars and back.”
Limoli points out that it would take probably months for astronauts to show dementia-like symptoms. But because the journey to Mars and back is quite long, the brain can worsen dramatically during such a long journey.
“This is not good news for astronauts who will take a two to three year journey to Mars,” says Limoli. “The space has unique hazards for astronauts. Exposure to these particles can cause a number of complications concerning the central nervous system that may occur during the trip, and even long after that too.
“You must not think only of memory problems, but also to anxiety, depression, less able to to make decisions, and so forth. Many of these negative consequences will play part on astronaut’s brains or even worsen throughout their lives.“
What about the astronauts on the International Space Station? Their brain is also affected by cosmic radiation? Limoli indicates that they are still within the protective magnetosphere. That means that they are not exposed to the same amounts of radiation astronauts en route to Mars.
Is there absolutely nothing we can do? Special shields that protect bedrooms of the astronauts is in consideration. But Limoli indicates that high-energy particles will anyway travel through the spacecraft. “You can not escape it.” But perhaps drugs can be developed that additional protect the brain during the dangerous and long journey. There are currently looking for a solution.