US, Russian astronauts undergo spacewalk to replace ISS hardware

Washington, June 3 (UNI) US and Russian astronauts ventured outside International Space Station (ISS) to conduct a six-hour-31-minute spacewalk to repair, retrieve and replace hardware of their respective segments of the complex.

Clad in Russian Orlan spacesuits, Expedition 13 Commander Pavel Vinogradov and NASA Flight Engineer and Science Officer Jeff Williams on Thursday opened the hatch to the airlock to begin the 65th spacewalk devoted to station assembly and maintenance, according to a NASA release here yesterday.

It was the sixth spacewalk for Vinogradov and the second for Williams and the walk began as the station flew 354 km over southern Asia, it said.

After setting up tools and tethers outside the airlock, Vinogradov and Williams used the telescoping boom attached to the airlock to transport them to the working area. There, Vinogradov installed a new nozzle to a valve that helps vent hydrogen into space from an oxygen generator in the space station module Zvezda.

The generator uses a process called electrolysis to separate hydrogen and oxygen from water in the system. Oxygen is circulated into the cabin atmosphere while hydrogen is vented overboard. A nozzle in the module's hull used to vent hydrogen had become clogged, reducing the generator's efficiency and forcing it to use the same vent line used by a contamination-monitoring device.

Two weeks ago, Vinogradov rigged a vent line inside the space station until the new vent valve nozzle could be installed outside the module. The refurbished generator will be re-activated on Monday. Next, the astronauts moved to the other end of the Zvezda module to photograph one of several antennas that provide navigational information for the unpiloted docking of the European Automated Transfer Vehicle, scheduled to make its maiden flight next year.

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