Chuck Bednar for redOrbit.com – @BednarChuck
NASA’s currently-planned future mission to Mars may be bad news for the astronauts likely to take part in the journey, as new research currently appearing in the journal Science Advances has found that long-term exposure to cosmic rays could cause cognitive impairment.
In the study, Dr. Charles Limoli from the University of California-Irvine and his colleagues reported that the highly-energetic particles space travelers would be exposed to may permanently impair their ability to acquire and interpret knowledge, as well as damage the central nervous system.
“This is not positive news for astronauts deployed on a two- to three-year round trip to Mars,” Dr. Limoli, a radiation oncology professor at the UCI School of Medicine, 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,” he added.
Testing the cognitive impact long-term space flight
During their experiments, the researchers subjected rodents to charged particle irradiation in the form of fully ionized oxygen and titanium, and found that exposure to those particles resulted in brain inflammation that disrupted the transmission of signals amongst neurons. They then looked at the communication network of those rodents’ brains using imaging scans.
They discovered reductions in the structure of nerve cells known as dendrites and spines, as well as additional synaptic alterations that further interfered with the ability of nerve cells to transmit electrochemical signals in an efficient manner. These differences, the authors explained, matched up with impaired performance on behavioral tests of both learning and memory.
This type of cognitive dysfunction is also common in brain cancer patients who have undergone various types of high-dose photon-based radiation treatments, the research team explained. These affects would take months to manifest in astronauts, but a trip to Mars would take long enough for such issues to develop as a result of lower-level cosmic rays.
So what does this mean for the NASA’s Mars mission?
As Gizmodo pointed out, the fact that humans have larger brains than rats means that the team’s findings are not directly transferable from rodents to astronauts, and continuous exposure may have a different affect than one high-intensity dosage of charged particle irradiation.
Nonetheless, the results of the study highlight the need for NASA to address these concerns.
“These findings do not preclude humans from partaking on long-term deep space travel,” Dr. Limoli told redOrbit via email. “They simply point to some of the additional risks associated with space travel beyond the Earth’s protective magnetosphere.”
“NASA is developing more effective shielding strategies to protect astronauts from charged particle exposure,” he added, “and is investing in research designed to identify pharmacologic countermeasures to provide additional protection to the radiation exposed brain.”
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