On August 20, 2012 Russian cosmonauts Gennady Padalka and Yury Malenchenko completed a five hour and 50 minute spacewalk having carried out all planned maintenance tasks on the International Space Station (ISS). The cosmonauts moved the "Strela-2” cargo boom from the "Pirs” docking compartment to the "Zarya” module and installed micrometeoroid debris shields on the exterior of the "Zvezda” service module. They also launched the "Sphere” microsatellite and collected a number of bio specimens from the surface of a docking module as part of the "Biorisk” scientific experiment. The unique Biorisk experiment studies the impact of vacuum, subzero and hot temperatures and radiation on biological objects. It is impossible to simulate these processes on Earth. Both Padalka and Malenchenko are veteran cosmonauts with a lot of experience venturing outside the orbital station. It was the ninth spacewalk for Padalka and the fifth for Malenchenko in their space careers.