An astronaut who spent a year in space came back changed at a biological level.
Early results of Nasa’s Twins Study found that 7 per cent of astronaut Scott Kelly’s genes did not return to their normal state when he returned to Earth two years ago, compared to that of his identical twin brother who never left the blue planet.
Researchers are analysing what happened to Mr Kelly before, during, and after his year-long stint aboard the International Space Station using his brother, Mark, as a benchmark.
The identical twins, the space agency is discovering, are no longer genetically the same.
The newest results, released at the 2018 Investigator’s Workshop for Nasa’s Human Research Program in January, corroborated a study released one year earlier in 2017. The results suggest that a 7 per cent transformation of Mr Kelly’s genes may relate to at least five biological functions and pathways.
The researchers focused on chemical changes in DNA and RNA, and they believe that side effects of space life — which can cause oxygen-deprivation stress, lead to dramatic shifts in nutrients, impact gene expression, and increase inflammation — caused potential long-term shifts for the astronaut.
These findings are valuable in helping understand what happens to humans while in space, especially over long periods of time, as the potential for a manned mission to Mars appears more and more likely.
The study shows that one of the more significant effects space had on Mr Kelly’s cells was hypoxia, which is a deficiency in tissue oxygenation, which is likely the result of a lack of oxygen and high carbon dioxide levels. The cells also may have seen damage to the mitochondria from that stress.
In addition to those changes, researchers also saw changes to Mr Kelly’s telomeres, which are the caps at the end of chromosomes which are considered markers of ageing. Those became elongated while in space but shrank within the first 48 hours of return to life on Earth. The research also showed changes in Mr Kelly’s blood clotting and bone formation, which they believe was likely the result of fluid shifts in zero gravity.
Nasa says the one-year mission is a part of their plans to launch a three-year mission to Mars. The research into the impact of space on the human body is seen as necessary before they send humans on a trip that would be three times as long as any human space trip in history.
