Expedition 51 Soyuz Commander Fyodor Yurchikhin of Roscosmos, bottom and Flight Engineer Jack Fischer of NASA, top, wave farewell prior to boarding the Soyuz MS-04 spacecraft for launch, Thursday, April 20, 2017 at the Baikonur Cosmodrome in Kazakhstan. Yurchikhin and Fischer will spend the next four and a half months aboard the International Space Station. Photo Credit: (NASA/Aubrey Gemignani)