Scott Kelly headed into space on Friday for a year-long stay at the International Space Station . His twin , retired astronaut Mark Kelly ' , showed up at launch as a joke . NASA administrator said that Mark Kellyfooled all of us ' Doctors will be studying brothers for the next year to see how space affects the body and behavior .
Scott Kelly headed into space on Friday for a year-long stay at the International Space Station . His twin , retired astronaut Mark Kelly , showed up at launch as a joke . NASA administrator said that Mark Kelly 'fooled all of us ' Doctors will be studying brothers for the next year to see how space affects the body and behavior .