If Humans Want To Get On Mars In The Next Two Decades, We Need To Address This Risk First

Mankind has big plans so that within the next twenty years, we can return to the Moon and reach further into space, like Mars. And while the technology that will take us there is gradually developing, our body may face obstacles in long-distance travel in space. According to a paper published in ENeuro journals, there are “unexpected potential problems” with the brain of mammals, which means we may not be ready to join such journeys.

At Colorado State University, a team of scientists, using a new “low-dose” radiation facility, observed that after months of being exposed to radiation that is similar to deep space’s radiation, mice began acting strangely. There were “severe impairments” in their memory and learning while getting extremely anxious. And while these symptoms are not surprising as the mice spent half a year in the experiment, the team also discovered physical changes in the mice’s brains which could be the explanation for those changes.

In the paper, the scientists make the case that their findings:

Traveling beyond low-Earth orbit can have negative impacts on the human brainAs the study involved mice only, the results might not necessarily apply to humans. However, these findings still come at a critical time. In April, through the twin study, NASA found that after a year on the ISS, astronaut Scott Kelly experienced several small physiological changes in comparison with his twin on Earth, but none of the changes were dangerous. Form those findings, it’s safe to say that humans can do well in extended low-earth orbit mission and this was a good place to start.

However, going to Mars is different from low-Earth orbit. Deep space missions will involve GCR (galactic cosmic radiation), which are particles accelerating so fast they have been stripped of their electrons, which leaves behind the nucleus only. These particles, as noted by NASA, can pass practically unimpeded via an astronaut's skin or a spacecraft, which can be threatening to human health.

Charles Limoli, the study’s co-author and a professor of radiation oncology, and his team at the school tried to mimic this environment as well as possible by keeping the mice for half a year in a low-dose radiation facility. While it’s not perfect, the team argue that this environment could indicate exposures from GCR in a long deep-space mission.

Over time, the team noticed concerning changes in the mice’s body and behaviors. In particular, the neurons in the radiation-exposed mice’s hippocampus were much less excitable than those of the control mice. Hence, there was a reduction regarding signaling, which could explain some changes in the mice’s behaviors during social interaction and memory tests.

In terms of social interactions, the exposed mice tended to actively avoid interacting with other mice while they seemed happy with interacting with a new mouse. In addition, they were slower in recognizing a new object or understanding when an old object was moved to a new position, suggesting negative impacts caused by radiation on their memory.

Meanwhile, it was also noted by the scientists that the long-term potentiation of the hippocampus’ neurons was hampered. Long-term potentiation is a kind of brain plasticity in which two neurons “learn” to fire with each other and generate a strong connection that can underpin memory and learning. The authors say that long-term radiation exposure appears to disrupt this important process.

They additionally note that the finding from a mouse’s brain can be translated into something useful for NASA to inform there remains challenges in human space travels. Furthermore, while space radiation may have different influences on different people, the team’s calculations show that many astronauts may struggle with cognitive dysfunction such as memory when they go into space.

The scientists say:

Amid a time when space companies are making plans for civilizations on Mars, the findings can be a significant push back. However, the risk is not insurmountable, and NASA is actively working on solutions to this problem.

In 2003, for instance, NASA funded the New York-based Brookhaven National Lab to establish the NASA Space Radiation Laboratory, with the initial aim of evaluating the risks of radiation similar to the radiation in deep space. The idea is to handle the risks better, the priority of the research will shift from assessing the risks to developing measures.

Hopefully, we can come up with solutions to achieve the goal of going to Mars in the next twenty years.