Sergey Prokopyev Status: Active 2/19/1975 – Nationality: Russian Type: Government Agency: Russian Federal Space Agency (ROSCOSMOS) Sergei Valeriyevich Prokopyev, born 19 February 1975 is a Russian cosmonaut. He is the commander of Soyuz MS-09, and flight engineer of Expedition 56/57 to the International space station.