Cosmonaut Gennady Padalka, left, moves a Russian construction crane. Fellow spacewalker Yuri Malenchenko, right, maneuvers his partner on a second crane anchored outside the International Space Station's Russian segment. Photo Credit/NASA TV

Russian cosmonauts readied the International Space Station for the eventual addition of a Russian Multipurpose Science Module during a spacewalk on Monday.

The big module, “Nauca,” and the European Robot Arm are expected to be launched together in 2013.

During a scheduled six hour spacewalk, Gennady Padalka and Yuri Malenchenko transferred an external construction crane, Strela-2, from the station’s Pirs airlock/docking module to Zarya, the station’s oldest compartment.

The move frees Pirs for a future jettison. The departure will open a docking port on the station’s Russian segment for Nauca.

Next, the two spacewalkers hand deployed Sfera, a stainless steel, satellite. Sfera will serve as a tracking target for Russian radar systems that monitor orbital debris. The passive 20-inch shere should remain in orbit for about three months.

Sfera satellite fades from view of spacewalkers Gennady Padalka and Yuri Malchenko. Photo credit/NASA TV

As their final major task, Padalka and Malenchenko installed five protective panels to the outside of Zvezda, the station’s Russian living compartment.

The panels will protect the compartment from an orbital debris impact that could prove catestrophic.

A U. S.spacewalk, the first orchestrated by NASA since July 2011, is scheduled for Aug. 30. It will team NASA astronaut Sunita Williams and Japanese astronaut Akihiko Hoshide for the replacement of a defective Main Bus Switching Unit on the station’s long solar power truss.

The MBSU is one of four avionics boxes that route solar power on the station’s U. S. segment.