His identical twin brother Mark kept his feet firmly planted on Earth.
The two men were identical, down to their cellular level, before the trip, but that can’t be said now.
Scott now differs from Mark when it comes to their DNA.
What? My DNA changed by 7%! Who knew? I just learned about it in this article. This could be good news! I no longer have to call @ShuttleCDRKelly my identical twin brother anymore. https://t.co/6idMFtu7l5
Scientists looked at the spaceman's metabolites, cytokines and proteins before and after his voyage. They said the mission caused Scott's "space genes" to switch on, and they didn't turn off after he returned to Earth. The experts believe they were turned on because of the stress of space travel, KTLA reported.
NASA said in the study that Scott's cells showed changes in the length of telomeres, the ends of chromosomes that show biological aging. They were lengthened while he was in space, but they returned to almost normal days after he landed. There was also damage to his DNA that was caused by radiation and the restriction on his calories. His collagen, blood clotting and bone formation also changed and because of zero gravity and fluid shifts.
Kelly's year-long trip in space was a precursor to planned three-year missions to Mars. Scientists needed to test how space missions that are longer than what is currently done impacts astronauts, KTLA reported.