Space flights lasting six months or more affect the physical state of the brain of astronauts, and crew members should take a break of at least three years before returning to space, a group of American scientists has established.
The researchers scanned the brains of 30 astronauts taken before space flights lasting two weeks, half a year and a year, after which they compared the results with the results of scans taken after returning to Earth. As it turned out, the ventricles – filled with cerebrospinal fluid cavities in the brain – after being on the ISS for more than six months, significantly expanded. The results of the study are of great importance for future long-term missions: in the foreseeable future, NASA and its partners will begin implementing the Artemis program with a permanent stay of a man on the Moon, and in the future they plan to send a man to deep space, including to Mars.
The cerebrospinal fluid provides the brain with protection and nutrition, as well as the removal of waste materials. While in space, bodily fluids in the body move and the brain is pressed against the upper region of the skull, which causes the ventricles to enlarge. Of the 30 astronauts who took part in the study, 8 went on two-week missions, 18 went on missions lasting 6 months, and 4 stayed in orbit for about a year. The scientists found that the degree of enlargement of the ventricles varied depending on the length of stay in orbit. The difference between the first and second groups turned out to be the most noticeable, but between the second and third it was no longer so significant, that is, after six months, the growth of the ventricles slows down. For astronauts in the “two-week” group, the effect was minimal, and this is good news for the commercial segment of the space industry.
The 11 astronauts participating in the study had more than three years to recover between missions, and after each subsequent flight they noted an increase in the ventricles. 7 astronauts had less time to recover, but the ventricles after the next flights in these cases increased slightly. The researchers were unable to determine exactly how long it takes for rehabilitation, but the analysis showed that after 6-7 months the brain recovered to 55-64% of its original level. Based on the data obtained, the scientists suggested that it takes at least three years for the full recovery of the ventricles.
The results of the study could be used by NASA and other space agencies to plan future missions, but more work is needed. The new project will study the long-term effects of a six-month stay in orbit – with a recovery period of up to five years.
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