Cape Canaveral, Florida:
Two astronauts left the International Space Station on Tuesday for a day of maintenance tasks, including installing a power cable needed for a new Russian laboratory due to arrive later this year.
Veteran NASA astronaut Christopher Cassidy and rookie partner Luca Parmitano, the first Italian to make a spacewalk, left the station's Quest airlock shortly after 8 a.m. EDT (1200 GMT) as the orbital outpost sailed about 260 miles (418 km) over the Arabian Sea.
"Have fun out there," crewmate Karen Nyberg radioed from inside the station, a $100 billion research complex owned by the United States, Russia, Japan and 11 European nations, including Italy.
Cassidy's first task was to replace a failed backup component of the station's Ku-band communications system, restoring redundancy.
Parmitano, meanwhile, maneuvered himself 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.
The privately owned California-based company, also known as SpaceX, is one of two U.S. firms hired by NASA to fly cargo to the station following the retirement of the space shuttles in 2011.
SpaceX's Dragon cargo capsules, which also are being developed to fly astronauts, are the only ones that return to Earth. Other cargo ships, including those flown by Russia, Europe and Japan, incinerate in the atmosphere after they leave the station.
The spacewalkers' to-do list also included repositioning some equipment delivered aboard a Dragon capsule in March. The gear - two grapple bars - may be needed by future spacewalkers tasked to remove station radiator panels.
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 multi-purpose 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 during a future spacewalk.
Cassidy and Parmitano have a follow-up spacewalk themselves next week to re-route cables that control the station's electrical system.
© Thomson Reuters 2013