Mars missions could leave astronauts with severe psychological damage — new study


Human space missions to Mars are the next big leap in space exploration, with NASA targeting the 2030s as a reasonable time to get the first humans there. But embarking on a journey to Mars is not like taking a flight to New York. Space is an extremely hostile environment for human life – from the lack of gravity and harmful radiation to the isolation and absence of night and day.

Deep space missions to Mars will be much more physically and mentally demanding than the journeys we have taken so far in 60 years of human space exploration. A round trip flight to Mars will last around 14 months, while the actual exploration mission will last at least three years. High and sustained levels of cognitive performance and effective teamwork are prerequisites for the safe and successful completion of these assignments.

But a new study, published in Frontiers of Physiology, found that the lack of gravity during such missions could negatively impact the cognitive skills and emotional understanding of astronauts.

From the first space missions, it is clear that exposure to “microgravity” (weightlessness) causes dramatic changes in the human body. This includes alterations in the cardiovascular, musculoskeletal and neural systems. On Earth, we sense gravity using our vision and various organs, including those inside the inner ear. When our head is upright, small stones in the ears – the vestibular otoliths – balance out perfectly on a viscous fluid. But when we move our head, gravity moves the fluid and this triggers a signal to the brain that our head has changed position. In space flight, this process no longer works.

Space flights can even negatively alter the brain anatomy of astronauts. Structural changes in the brain have been observed in astronauts after returning from the International Space Station (ISS). These include the brain moving physically upward inside the skull and the reduced connectivity between areas of the brain layer, the cortex, and those inside.

How these changes affect behavior is not yet fully understood, but scientists are making progress. We know that astronauts can suffer from disorientation, perceptual illusions, balance disturbances and motion sickness. But these results are often based on small samples.

Simulate microgravity

The new NASA-backed study investigated the effects of microgravity on cognitive performance. But rather than sending their 24 study participants into space, they sent them to bed. This is because the impact of a certain type of bed rest is analogous to the effects of microgravity – we use it a lot in research. When we are standing our body and vestibular otoliths are in the same direction as gravity, while when we are lying down they are orthogonal (at right angles).

Image of a study participant.