How Space Affects the Human Body

March 20, 2017

While the complete results for the Twins Study have not yet been released by NASA, the preliminary results have teased some surprising findings. NASA astronaut Scott Kelly returned home last March after nearly one year living on the International Space Station. His identical twin brother, Mark, remained on Earth. This situation gave NASA the perfect opportunity for a nature vs. nurture experiment.

Even with only early results, researchers found that living in space drastically changes a person’s biology and gene expression. Prior to Scott’s 340- day International Space Station mission, samples and measurements were taken from both Scott and Mark, so they could be compared upon Scott’s return.

Identical twins are practically the same genetically, but the samples they took from Scott and Mark after Scott’s time in space showed that their bodies and genes are no longer the same. Researchers found that Scott’s telomeres, which are the protective end caps on the end of DNA strands, were longer than Mark’s. Usually the telomeres shrink as humans age, so these results were surprising. The telomeres have since returned to normal.

Researchers have been conducting many other scientific investigations on the way space has affected the twins. The Biochemical Profile Investigations found a decline in bone formation in Scott during the second half of the mission. Another investigation of microbiome in the GI tract found differences in the types of microbial species in the gut that were observed in Scott.

All of these preliminary findings are fascinating, and we are eager to explore the full results from the study. Through the Twin Study, we can start to understand the effects space travel can have on human bodies and help to ensure the safety of astronauts in future space exploration missions.