Nasa astronauts launch daring spacewalk to fix International Space Station robot arm

Spacewalking astronauts gave a hand to the International Space Station's robot arm Tuesday (23 January). As the federal government geared back up 250 miles below, Nasa astronauts Mark Vande Hei and Scott Tingle floated outdoors to install a new mechanical gripper.

Because of the lingering effects of the government shutdown, the spacewalk got started in the morning without live coverage on Nasa TV. An on-air message simply stated: "We regret the inconvenience." Nearly an hour into the spacewalk, however, Nasa TV came alive and began broadcasting the event with typical blow-by-blow commentary.

Space station operations were largely unaffected by the three-day shutdown. Considered essential personnel, Nasa Mission Control kept watch as usual at Johnson Space Centre in Houston, Texas.

Vande Hei performed a similar spacewalk last October, when he replaced the first of two original hands on the Canadian-built arm. This second new hand will go on the opposite end of the 58-foot arm, able to move like an inchworm by grabbing hold of special fixtures.

The bulky bundle of latches — more than 3 feet, or a meter, long and weighing more than 440 pounds, or 200 kilograms — needed to be replaced because of wear and tear. It's been in orbit, grabbing cargo capsules and performing other chores, since 2001.

Tingle had to use extra muscle to release a stubborn bolt securing the spare mechanical arm. "Nice work," Vande Hei said. "And the crowd goes wild," chimed in Mission Control.

It was the first spacewalk for Tingle, who arrived last month, and the third for Vande Hei.

"Make us proud out there," astronaut Joe Acaba told the spacewalkers from inside. "We'll have hot chow for you when you get back." Vande Hei will go back out Monday (29 January) with another astronaut to finish the job. Then the two Russians on board will conduct a spacewalk 2 February to install a new antenna on their country's side of the outpost.

The space station is home to three Americans, two Russians and one Japanese.