Expedition 51 prime crewmember Fyodor Yurchikhin signs a commemorative book in a traditional ceremony.

At the Gagarin Museum at the Gagarin Cosmonaut Training Center in Star City, Russia, Expedition 51 prime crewmember Fyodor Yurchikhin of the Russian Federal Space Agency (Roscosmos, front row, left) signs a commemorative book in a traditional ceremony April 3. Looking on are his crewmate, Jack Fischer of NASA (front row, right) and the backup crewmembers in the back row, Sergey Ryazanskiy of Roscosmos (back row, left) and Randy Bresnik of NASA (back row, right). Yurchikhin and Fischer 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. Photo: NASA/Rob Navias.