Russian cosmonauts leave space station to lay cables for new lab
* Russians begin 6.5-hour spacewalk
* U.S. spacesuit leak still under investigation
By Irene Klotz
CAPE CANAVERAL, Fla., Aug 16 (Reuters) - Two Russian cosmonauts floated outside the International Space Station on Friday to set up power and ethernet cables for a new research laboratory scheduled to arrive in December.
Flight engineers Fyodor Yurchikhin and Alexander Misurkin opened the hatch on the station's Pirs airlock at 10:39 a.m. EDT (1439 GMT) to begin a 6.5-hour spacewalk.
Yurchikhin, who was making his seventh spacewalk, and Misurkin, on his second, were scheduled to route two power cables and an Ethernet line for a new Russian multipurpose laboratory called Nauka.
"There's a lot of intricate and delicate stringing (of the cables) through handrails and hook points," NASA mission commentator Rob Navias said during a televised broadcast of the spacewalk.
The outing is the third of six spacewalks Russia plans to conduct this year.
NASA meanwhile is still investigating the cause of a spacesuit helmet leak that forced two other crew members at the space station to abort a spacewalk on July 16.
Russia's Orlan spacesuits are different from NASA's but "due diligence was paid in preparation for this spacewalk," Navias said.
"Everything was in good shape," he added.
In addition to rigging cables between the Russian Zarya and Poisk modules, Yurchikhin and Misurkin planned to attach a panel of experiments on Poisk that will remain outside to expose materials to the space environment.
The cosmonauts are scheduled for another spacewalk on Aug. 22 to install a swiveling platform for a telescope.
Russia's Nauka module will serve as research lab, docking port and airlock, and replace the Pirs docking compartment, which will be detached from the space station and flown into the atmosphere, where it will be incinerated.
The station, a $100 billion project of 15 nations, flies about 250 miles (about 400 km) above Earth. It has been permanently staffed by rotating crews of astronauts and cosmonauts since November 2000. (Reporting by Irene Klotz, Editing by Jane Sutton and Paul Simao)