Stock Photo - At the Gagarin Cosmonaut Training Center in Star City, Russia, outside Moscow, Expedition 31 Soyuz Commander Gennady Padalka (seated), flanked by Expedition 31 prime and backup crew members, signs a traditional cosmonauts' log at the site's Yuri Gagarin museum. Front at left is NASA astronaut Joe Acaba, flight engineer, and at front row, right is Russian cosmonaut and Flight Engineer Sergei Revin. Back row, from left are Expedition 31 backup crew members Kevin Ford of NASA and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin. Acaba, Padalka and Revin are preparing for the launch scheduled for May 15 that will take them to the International Space Station on the Soyuz TMA-04M spacecraft from the Baikonur Cosmodrome in Kazakhstan.