Despite calls to speed up the process, it is probably a good thing that NASA isn’t rushing a manned trip to Mars. There is still a good deal that scientists don’t know about Mars and the space between here and there.
According to new research by Charles Limoli and colleagues at the University of California at Irvine, exposure to cosmic radiation could cause serious and permanent brain damage to unprotected astronauts. That type of radiation is believed to be very strong outside of the Earth’s protective magnetosphere.
Scientists have very little experience with deep space and the “highly energetic charged particles” that permeate it. Long term exposure to those particles could cause damage to the central nervous system as well as cognitive impairment according to the research.
“This is not positive news for astronauts deployed on a two- to three-year round trip to Mars. 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,” said Limoli, a professor of radiation oncology in UCI’s School of Medicine in a statement.
For the research, rodents at NASA’s Space Radiation Laboratory at the Brookhaven National Laboratory were exposed to the type of charged particle radiation likely to be found in deep space.
The specimens were sent back to Limoli’s lab where researchers found significant brain inflammation which was disrupting transmission signals between neurons.
According to the researchers, “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.”
Upon further testing, the rodents showed decreased performance in simple learning and memory tasks. The results were similar to those shown by brain cancer patients undergoing radiation treatments according to Limoli.
The researchers believe that it would take months for the damage to begin to appear in humans, but the time it would take to reach Mars is more than sufficient.
All of this does not mean that a trip to Mars is off. Limoli and other researchers are not looking at ways to protect astronauts from feeling the full impact of the radiation. One possible method is providing increased radiation shielding for certain areas of the ship, such as sleeping compartments, so that the exposure to high levels of radiation is not constant.
The researchers are also looking at possible medical treatments which might be used to prevent some of the damage.
“We are working on pharmacologic strategies involving compounds that scavenge free radicals and protect neurotransmission. But these remain to be optimized and are under development,” said Limoli.
The researchers warn however that the particles will penetrate and traverse the ship regardless. While the amount of radiation could be reduced there is currently no known way to fully protect against them.
As for Mars itself, the planet has a much weaker magnetic field than the Earth does and both cosmic and solar radiation are higher on the Martian surface. However, according to research conducted using the Curiosity Rover and published in January of 2014, the levels are not nearly as high as those expected in deep space.
Limoli’s research, published in the journal Science Advances, does mean that important questions need to be answered about the viability of permanent human settlements on Mars and the implications of potential crewed space travel to points even further away.
