Astronauts complete 6hrs of spacewalk to tackle backlog

·         Luca Parmitano became the first Italian to make a spacewalk 

·         Christopher Cassidy also went on walk to tackle maintenance chores

·         Pair installed power cable for new Russian lab to be installed this year 

·         Fourth spacewalk this year with five more planned 

Two astronauts completed a six hour spacewalk yesterday to tackle a backlog of chores outside the International Space Station. Luca Parmitano became the first Italian to make a spacewalk as he and his NASA colleague, American astronaut, Christopher Cassidy carried out a series of maintenance tasks. The pair installed a power cable needed for a new Russian laboratory due to be installed this year and replace a failed backup component of the station's Ku-band communications system.The astronauts left the station's Quest airlock shortly after 12noon GMT. The $100billion research complex is jointly owned by the U.S., Russia, Japan and 11 European nations.Parmitano's first task was to move to the right side of the station's solar power truss to pick up a pair of science experiments that will be returned to Earth aboard a future Space Exploration Technologies' cargo ship.Cassidy, who was making his fifth spacewalk, installed a power and data cable from the station's Unity connecting node to the Russian part of the International Space Station, completing one of the main goals of the outing.The cable is part of a system that will be needed for a new Russian multipurpose laboratory called Nauka that is due to launch later this year.The new module will replace Russia's Pirs airlock, as well as serve as a research laboratory and berthing port. Russian cosmonauts will install the rest of the cable on a future spacewalk.Before heading back inside the station's airlock Cassidy and Parmitano retrieved a failed camera, put a cover on the shuttle's no-longer-needed docking port and began reconfiguring cables that could be used to control the station's electrical system in case of a partial power outage.They also repositioned some equipment delivered aboard a Dragon capsule in March. The gear - two grapple bars - may be needed by future spacewalkers removing station radiator panels.Mission Control radioed up to the crew: 'A really great day.'NASA said the tasks had been piling up over the past couple of years. Managers wanted to wait until the to-do list was long before committing to the time-consuming spacewalks.Parmitano, 36, a major in the Italian Air Force, arrived at the space station at the end of May for a six-month stay, while  Cassidy, 43, will finish his half-year mission in September.The rest of the space station crew - one American and three Russians - assisted the spacewalkers from inside.This was the fourth spacewalk this year with five more planned, mostly by Russians.In all, 170 spacewalks have been performed over the past 15 years at the space station, totaling nearly 1,074 hours or 45 days.The astronauts plan to resume work on the jumper cables during a follow-up spacewalk on July 16.