Expedition 46 Commander Scott Kelly of NASA, center, is embraced by Russian cosmonaut Mikhail Kornienko of Roscosmos, right, after the two arrived at the Zhezkazgan Airport in separate helicopters from the Soyuz TMA-18M spacecraft landing site on Wednesday, March 2, 2016 (Kazakh time). Kelly and Kornienko completed an International Space Station record year-long mission to collect valuable data on the effect of long duration weightlessness on the human body that will be used to formulate a human mission to Mars. Russian cosmonaut Sergey Volkov of Roscosmos returned after spending six months on the station.