FILE - In this March 4, 2016, file photo, NASA astronaut Scott Kelly, left, and his twin Mark get together before a press conference in Houston. Scott Kelly set a U.S. record with his a 340-day mission to the International Space Station. Kelly is exploring lots of options for the next step in his life. But hes saving the serious job discussions for retirement, coming up April 1. His identical twin, Mark, retired as an astronaut soon after the shuttle program ended in 2011, yet agreed to medical testing as part of the unprecedented twins study that got under way well before Scotts March 2015 launch from Kazakhstan. (AP Photo/Pat Sullivan, File)
