CAPE CANAVERAL, Florida - Astronauts tried out the International Space Station's newest piece of equipment Saturday, but it was a very limited test.

Space shuttle Discovery crew members Akihiko Hoshide and Karen Nyberg moved the Japanese Kibo lab's robotic arm for the first time, moving it very slightly with a series of commands.

"The very first manoeuvre was completed successfully,'' Hoshide told Japanese flight controllers near Tokyo.

Full deployment of the 10-metre arm will be done after Discovery leaves the station next week. However, it won't be used for any actual work until after the billion-dollar lab's third and final section, a "porch'' for exterior experiments, as well as a second but smaller robotic arm are launched into orbit next year.

The initial deployment of the robotic arm provides room for astronauts Michael Fossum and Ronald Garan Jr. to finish some final outfitting of the lab on Sunday during their third and final spacewalk of the current shuttle mission.

Fossum and Garan were busy Saturday preparing equipment for their spacewalk.

Kibo, Japanese for hope, was delivered by the shuttle and installed on the space station earlier this week.

The lab's attic -- essentially a four-metre shed, or closet, for spare tools and equipment -- was popped atop the 11-metre lab on Friday by astronauts operating the space station's robot arm. Even before Friday's addition, the bus-size Kibo was the biggest room at the space station.

The attic had been in a temporary location at the space station since March. There was not enough room on a space shuttle to fit both the attic and lab, so NASA split them into two flights.

In an interview with The Associated Press on Friday, Discovery commander Mark Kelly said Kibo was so "incredibly big'' that the astronauts had to take extra care inside of it.

"You can get out in the middle of it and you can't reach a handrail and you could possibly get stuck there for a little while,'' Kelly said.

Mission Control commented later Friday that Kibo was looking more like a lab. When the astronauts opened up Kibo on Wednesday, a day after installing it, the lab was empty and had lots of room for weightless acrobatics. Racks for experiments quickly consumed some of the space.

"I guess there are no more dance parties,'' Mission Control joked.

Late Friday, Mission Control asked the astronauts to take photos of two thermal protective panels on Discovery's right wing. Mission Control said embedded sensors had picked up some slight pulses a few days earlier, indicating possible micrometeorite impacts, and while engineers did not think anything was amiss they wanted to make certain.

The astronauts sent down more than 50 digital photos of the two wing panels.

The wing sensors are one of NASA's many safety measures put in place after Columbia was destroyed during re-entry in 2003 as a result of a gashed wing.