At the Cosmonaut Hotel crew quarters in Baikonur, Kazakhstan, the Expedition 51 prime and backup crewmembers take a stroll down the Walk of Cosmonauts April 13 as part of their pre-launch activities. From left to right are backup crewmember Randy Bresnik of NASA, prime crewmember Fyodor Yurchikhin of the Russian Federal Space Agency (Roscosmos), backup crewmember Sergey Ryazanskiy of Roscosmos and prime crewmember Jack Fischer of NASA. Fischer and Yurchikhin will liftoff April 20 from the Baikonur Cosmodrome on the Soyuz MS-04 spacecraft for a four and a half month mission on the International Space Station. NASA/Victor Zelentsov