Two International Space Station (ISS) astronauts left the orbiting laboratory to conduct maintenance work Monday. Russian flight engineers Fyodor Yurchikhin and Alexander Misurkin replaced a main valve on the space station, orbiting 400 kilometers above Earth. The astronauts also planned to install clamps and retrieve science experiments. Some of the work will allow for the arrival of a new Russian compartment at the end of the year. The third spacewalk this year was under the direction of Russian Mission Control outside Moscow. The four other space-station residents monitored the action from inside. The crew currently includes three Russians, two Americans, and one Italian. The Italian and one American will conduct two spacewalks for the National Aeronautics and Space Administration (NASA) in July. Begun in 1998, the ISS still lacks one room. The Russian Space Agency plans to launch a research laboratory to replace the Pirs air lock that has been in place since 2001. An unmanned Proton rocket will lift the laboratory, which also will serve as an air lock for spacewalk preparations and a docking port for visiting craft.
