There is discussion of a U.S. manned mission to Mars but if recent history is any indication, the next president will undo the space program of the current one, just as the current one undid the manned space program of the last.

It may be for the best, at least as far astronaut safety is concerned. The destructive particles in galactic cosmic ray exposure can forever impair cognition, according to an oncology paper in Science Advances.

Researchers have found that exposure to highly energetic charged particles - much like those found in the cosmic rays that bombard astronauts during extended spaceflights - cause significant damage to the central nervous system, resulting in cognitive impairments.

For the study, rodents were subjected to charged particle irradiation (fully ionized oxygen and titanium) at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory before being sent back.

The researchers found that exposure to these particles resulted in brain inflammation, which disrupted the transmission of signals among neurons. Imaging revealed how the brain's communication network was impaired through reductions in the structure of nerve cells called dendrites and spines. Additional synaptic alterations in combination with the structural changes interfered with the capability of nerve cells to efficiently transmit electrochemical signals. Furthermore, these differences were parallel to decreased performance on behavioral tasks designed to test learning and memory.

"This is not positive news for astronauts deployed on a two- to three-year round trip to Mars," said Charles Limoli, a professor of radiation oncology in U.C. Irvine's School of Medicine. "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."

Similar types of more severe cognitive dysfunction are common in brain cancer patients who have received various photon-based radiation treatments at much higher doses. In other research, Limoli studies the impact of chemotherapy and cranial irradiation on cognition.

While cognitive deficits in astronauts would take months to manifest, Limoli said, the time required for a mission to Mars is sufficient for such deficits to develop. People working for extended periods on the International Space Station do not face the same level of bombardment with galactic cosmic rays, as they are still within the protective magnetosphere of the Earth.

What can be done to protect astronauts speeding off to the red planet?

As a partial solution, Limoli said, spacecraft could be designed to include areas of increased shielding, such as those used for rest and sleep. However, these highly energetic particles will traverse the ship nonetheless, he noted, "and there is really no escaping them."

Preventative treatments offer some hope. "We are working on pharmacologic strategies involving compounds that scavenge free radicals and protect neurotransmission," Limoli said. "But these remain to be optimized and are under development."

Vipan Kumar Parihar, Barrett Allen, Katherine Tran, Trisha Macaraeg, Esther Chu, Stephanie Kwok, Nicole Chmielewski, Brianna Craver, Janet Baulch and Munjal Acharya of UCI and Francis Cucinotta of the University of Nevada, Las Vegas contributed to the study, which NASA supported through grants NNX13AK70G, NNX13AD59G, NNX10AD59G and NNX15AI22G.