Researchers have released new findings on how extended stays in microgravity affect the human brain. A recent study published in the Proceedings of the National Academy of Sciences analyzed health data from 26 astronauts who spent time aboard the International Space Station (ISS). Of these, 15 underwent both preflight and postflight brain measurements, while existing data was used for the other 11.
The study found that after spaceflight, the brain shifts upward and backward inside the skull. Different regions of the brain moved independently, and although these changes were only a few millimeters, they affected both motor and sensory areas. Astronauts who spent longer periods in microgravity experienced greater changes, but even those with missions as short as two weeks showed measurable shifts.
These alterations led to what researchers described as “sensory conflicts.” Astronauts sometimes reported brief episodes of motion sickness or spatial disorientation while in space. Upon returning to Earth, some experienced balance problems. Follow-up monitoring indicated that it could take up to six months for an astronaut’s brain orientation to return to normal after long-duration missions.
Experts agree that more research is needed to fully understand how space travel impacts human health. Current technology does not yet provide solutions such as artificial gravity or adequate radiation shielding. Additional needs include autonomous medical care, mental health support, and reliable evacuation procedures. Until these challenges are addressed, experts say long-term human presence on the moon or Mars remains unlikely.
A former NASA mission planner commented: “As a former NASA mission planner, I would signal a ‘no-go’ for human colonization of the moon and Mars. The human body’s functions cannot tolerate the long-term effects of a low-gravity environment.”
Responding to concerns about future colonization efforts, medical experts wrote: “As for a decision on colonizing the moon or Mars, we are relieved this decision isn’t up to us. But experts like yourself appear to agree about several important things. One is that we need more research to understand how the human body responds to the rigors of space. The other is that the technology to keep people healthy so far from Earth is not yet in place. This includes things like artificial gravity and radiation shielding. We would also need autonomous medical care, mental health support and on-demand evacuation procedures. Experts in the field agree that until those gaps are closed, deep space missions, including long-term stays on the moon or Mars, will remain out of reach.”
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