Miami (AFP) - Two American astronauts floated outside the International Space Station Friday for the third spacewalk this month aimed at repairing the orbiting outpost's robotic arm and replacing old video cameras.
NASA's Joe Acaba and Randy Bresnik officially began the spacewalk at 7:47 am (1147 GMT) when they switched their spacesuits to battery power, then ventured outside the airlock into the vacuum of space.
The pair hope to replace a degraded camera at the end of the 57-foot (17-meter) robotic arm, finish lubricating its newly installed latching end and replace a blown fuse, among other tasks.
The aging arm, made by Canada and named the Canadarm, is used to move objects around outside the station and to grab incoming cargo ships.
Installed 16 years ago, its latching end lost its gripping ability in August. A key piece of equipment called the latching end effector was replaced during the October 5 spacewalk.
Further lubrication work was done on the October 10 spacewalk, and a new high definition video camera was also installed outside the research lab.
On Friday, astronauts plan to replace another camera, nicknamed "Old Yeller" because it broadcasts in yellow hues.
The spacewalk is the 205th in the history of the space station, an international collaboration involving more than a dozen countries.
Bresnik, 50, a former Marine Corps aviator who goes by the nickname "Komrade," has led all three of the October spacewalks, and on Friday is making his fifth career excursion outside the space station.
His colleague Acaba, 50, is the first person of Puerto Rican heritage to become an astronaut, according to his NASA biography.
The former hydro-geologist and educator became an astronaut in 2004 and spacewalked twice in 2009 during the space shuttle era.
Friday's outing is the ninth this year for NASA. Russian cosmonauts have ventured out on one spacewalk this year.