Expedition 51 backup crewmembers pose for pictures in front of a Soyuz training mockup at the start of final crew qualification exams.

At the Gagarin Cosmonaut Training Center in Star City, Russia, Expedition 51 backup crewmembers Sergey Ryazanskiy of the Russian Federal Space Agency (Roscosmos, left) and Randy Bresnik of NASA (right) pose for pictures in front of a Soyuz training mockup March 30 at the start of final crew qualification exams. They are backups to Fyodor Yurchikhin of Roscosmos and Jack Fischer of NASA, who will launch April 20 on the Soyuz MS-04 spacecraft from the Baikonur Cosmodrome in Kazakhstan for a four and a half month mission on the International Space Station. Credit: NASA/Rob Navias