After living for nearly a year aboard the International Space Station, NASA astronaut Scott Kelly says he's two inches taller than his identical twin brother Mark, NBC News reported.
Kelly reports that he that overall he "feels pretty good," but now begins what may be a year-long project to monitor his health. One unique advantage he provides to NASA's doctors is his identical twin brother, Mark, a former NASA astronaut who spent last year with his feet planted on terra firma.
Comparing the twins will help researchers spot any genetic changes that might have occurred in Scott while in space. NASA will be on the lookout for possible brittle bones, weak muscles, decreased heart mass and possible increased cancer risk, among other health effects a year in space could cause to the human body.