How 1-Year Space Mission Affected Astronaut Twin Scott Kelly: Early Results

Spending a year in space affected former NASA astronaut Scott Kelly's body in subtle but potentially significant ways, new research suggests. Kelly and cosmonaut Mikhail Kornienko flew the first-ever yearlong mission aboard the International Space Station (ISS), wrapping up the flight with a touchdown on the steppes of Kazakhstan last March. Part of this work involves Scott Kelly's identical twin brother Mark — a former NASA astronaut who flew on four space shuttle missions.