Members of the backup crew of the 21st visiting expedition to the International Space Station, American astronaut Donald Pettit, Russian cosmonaut Ivan Vagner and Belarusian cosmonaut Anastasia Lenkova (right to left) undergo comprehensive qualification training at the Yuri Gagarin Cosmonaut Training Centre in Zvyozdny Gorodok (Star City), 25km northeast of Moscow. Photo: VCG