HOUSTON — Spacewalking cosmonauts Fyodor Yurchikhin and Alexander Misurkin strung solar power and Ethernet cable extensions outside the Russian segment of the International Space Station on Aug. 16, the latest step in a multi-excursion effort to prepare the station for the arrival of Russia’s Nauka Multipurpose Laboratory Module (MLM).

The 22-ton MLM, a combination lab and airlock, is scheduled to launch from the Baikonur Cosmodrome in Kazakhstan atop a Proton rocket in December at the earliest. The cabling activities will enable the MLM to operate with U.S. segment-generated solar power and data connectivity.

The excursion unfolded without major difficulties. The two men emerged from the Russian segment’s Pirs airlock module with reels of solar power and Ethernet cables. The utility lines were strung along the adjoining Poisk and Zarya modules. Zarya borders the station’s U.S. segment. Yurchikhin and Misurkin largely retraced their steps from a June 24 spacewalk in which they installed a series of cable clamps on the two modules to secure the future utility cables.

Their cosmonauts’ efforts also built on the work of U.S. and European Space Agency astronauts Chris Cassidy and Luca Parmitano. During a July 9 spacewalk, Cassidy strung solar power cabling across the U.S. Unity node to the Russian segment.

Parmitano was in the process of adding an Ethernet cable extension on July 16 when the helmet on his NASA spacesuit began to fill with water. The NASA-managed spacewalk was terminated at 92 min., after Parmitano retreated to the safety of the U.S. airlock.

The source of the leak and the identification of contributing factors are the focus of a formal NASA mishap investigation that is still underway. U.S.-sponsored spacewalks are on hold until the problem is identified and a repair strategy executed.

During their latest spacewalk, the cosmonauts also installed a materials exposure experiment, Vinoslivost.

The MLM will replace the Pirs module, which will be propelled away from the station by a Progress cargo capsule that docked to the 12-year-old airlock compartment on July 27.

The Aug. 16 spacewalk marked the sixth spacewalk this year at the six-person outpost, and the third of six planned by cosmonauts. Yurchikhin and Misurkin are scheduled to suit up again Aug. 22 for a spacewalk to replace an external laser communications experiment with a swiveling mount for a future Russian segment optical telescope, and to salvage a docking target assembly from Pirs.