After spending a year in space, NASA astronaut Scott Kelly is not the man he used to be — at least genetically speaking. His genetic expression has changed, according to preliminary results from a NASA study that compared the bodily changes between the astronaut and his identical twin, who stayed on Earth while Kelly was aboard the International Space Station. About 7 percent of Kelly’s genes have yet to “return to normal” ― almost two years after his yearlong expedition came to an end.