ISS011-E-13021 (14 September 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, works with the European Space Agency (ESA) Matroshka radiation experiment in the Zvezda Service Module of the International Space Station. Matroshka, a human-torso-like device, was retrieved from the exterior of the station during an August spacewalk, for return to Earth. The experiment is designed to better understand the exposure of astronauts, including those making spacewalks, to radiation.