According to a new NASA study, orbit has interesting effects on the human.br But their study also required a unique data-set which is difficult for the space agency to obtain, they had a pair of twins who were astronauts.br Using Scott and Mark Kelly, NASA set Scott into orbit for a year-long mission to see if space had definitive effects on the body and brain.br Their results found that Scott's DNA has changed by 7-percent when compared to Mark's, but Scott also grew about 2-inches during his year-long mission.br Mark stayed on Earth during Scott's mission, but the brothers are now both retired from NASA.