Science 364, eaau8650 (2019)

Long-term spaceflight of roughly a year induces physiological changes, some of which are unchanged after 6 months.

Credit: NASA/Science Source

The effects of long-term spaceflight on human physiology are not known, and but an understanding is needed to increase preparedness for space exploration, such as to Mars.

Researchers from the National Aeronautics and Space Administration (NASA) and collaborating institutes took a large panel of genome-wide genetic and physiology measurements from various cell types and tissues in a set of identical twins, one of which was on the International Space Station for a period of 341 days, while the other remained on Earth for that period. Studying twins reduced any changes due to genetics.

The large majority of changes that seemed to be the result of spaceflight (and, hence, lack of gravity, radiation exposure and stress upon returning to earth, among other factors) were reversible adaptations. Some changes, such as cognitive performance, did not return to baseline after 6 months and could represent challenges for future missions.