Endeavour crew begin final spacewalk

Washington: Two astronauts ventured into open space on Monday to install cameras on the International Space Station's new Japanese laboratory during the final spacewalk of the US shuttle Endeavour mission.

Chris Cassidy and Tom Marshburn floated out of the ISS about one hour earlier than planned as they began the mission's fifth spacewalk, which was expected to last six and a half hours.

While Mashburn secures multi-layer insulation around the station's two-armed robot, the Special Purpose Dexterous Manipulator known as DEXTRE, Cassidy will separate the power channels shared by two of the station's four gyroscopes.

Splitting the channels of the two gyroscopes, which provide non-propulsive altitude control for the station, will prevent a failure on one channel from disabling both of the fixtures, the Nasa said.

The spacewalking duo will then install video cameras on the front and back of Japan's Kibo laboratory, which became the station's biggest room when it was installed last year.

For their final task, the astronauts will deploy a payload on another part of the ISS that will provide storage capability for spare space station hardware.