Humans want to be an interplanetary species. Stephen Hawking wants us to become an interplanetary species. Elon Musk wants us to become an interplanetary species. Even NASA is getting on board. But. Before we can start building colonies on the moon or Mars or a way station on Titan or whatever else, we have killer space radiation to contend with.
It isn’t as simple as SPF and shades, or even high-tech spacesuits and spacecraft designed to resist the gene-mutating, carcinogenic cosmic rays that threaten astronauts from everywhere once they venture beyond Earth’s magnetic field. This is why a group of biologists and biochemists, including Franco Cortese of the Biogerontology Research Foundation along with Sylvain V. Costes and Afshin Beheshti of NASA’s Ames Research Center, recently published a study in the journal Oncotarget that addresses the potential dangers of deep-space missions and living in colonies on anywhere but Earth.
“Although cosmic radiation risks include cataracts, circulatory disease, damage to the central nervous system and others, risk of fatal cancer is the major component and contributor to overall radiation health risks that are being estimated and used for operation and planning of human space missions,” said the scientists.
The extensive study, which looks like something out of a Starfleet Academy bio textbook, explores how we an enhance human radioresistance (which is, by the way, a superpower of tardigrades) to improve the health and extend the longevity of astronauts and what Musk and Hawking imagine to be a future spacefaring civilization. Even robotic spacecraft that probe other planets aren’t completely immune to the effects of hanging out in space for too long, so you can only imagine the danger to humans.
“Cosmic radiation and microgravity represent two major environmental contributors to human health risks and substantially limit the prospects of long spaceflights,” Cortese and his colleagues said. Scary.
Even scarier is that these risks have been overlooked in favor of the excitement surrounding spaceflight technologies that keep advancing ahead of biochemical advancements that could potentially save lives hundreds of thousands of miles away from the home planet. Mars may be looked at by many as the next frontier, but the radiation levels on the Red Planet are high enough to exceed even NASA limits.
Space radiation is mostly comprised of solar particle events (SPE), geomagnetically trapped radiation and galactic cosmic radiation (GCR). The high-energy particles in GCR make it the main threat to humans who are exposed—the levels that spacefarers would face on a return trip to Mars are astronomical. So are the risks for cancer, heart disease, and central nervous system damage. GCR can even penetrate shielding materials meant to protect the spacecraft and put its crew at even more risk from secondhand exposure. Because of this, the scientists propose that it is not just equipment, but our species that needs to be radioresistant.
How exactly could the human body be enhanced to fight off ionizing radiation or at least repair itself from the damage? We could take a scene out of Alien and put the entire crew into hibernation mode, with all metabolic processes that could be affected by space radiation plummeting to the absolute minimum. We could also find methods to modify DNA for radioresistance and repair chromosomes that have been damaged by high levels of LET (how much energy is blasted out by a particle or photon as it shoots through space). Low-dose X-rays have been able to counteract the its effects.
Scientists are even conducting experiments to express radioresistant genes already in the body and grow radioresistant tissue that could replace damaged tissue. It may even be possible to transfer certain traits from tardigrades to human DNA. Until that can actually happen, the safest best for space agencies looking to select astronauts is running tests to determine which individuals have the most radioresistance.
“While many of the strategies proposed… may seem speculative, they should be considered as a foundation for future research directions,” the researchers said.
For now, just take a moment to appreciate that sunblock is effective nowhere else in the universe but Earth.