In the thinking organs of people who have been in zero gravity for a long time, dangerous physiological changes occur. The absence of gravity, as scientists have found, compresses the brain and narrows its convolutions.
Therefore, scientists quite rightly fear that long-term space missions (for example, an expedition to Mars) may turn into significant problems - astronauts with compressed brains may begin to behave unpredictably.
“This is the same phenomenon that underlies the visual impairment seen in astronauts aboard the ISS. The brain is pressed against the skull, and the convolutions, accordingly, narrow. We do not yet know how exactly this affects the work of the brain, but it is clear that this feature of weightlessness does not lead to anything good, - quoted by the New England Journal of Medicine, Dr. Donna Roberts, one of the authors of the study.
In general, the organization of the future flight to Mars now has not only technical, but also physiological difficulties. Which, which is especially alarming, has not yet been resolved. If scientists don't come up with anything, then people probably won't be able to colonize other planets.
Kolesnikov Andrey