Shuttle Crew Hits Mission Midpoint with Robot Arm Test
The fading blue limb of the Earth backlights the shuttle Discovery docked at the ISS. At center is the station's six-jointed Japanese robotic arm folded up at the outboard end of the new Kibo lab.
Credit: NASA TV.

HOUSTON — Astronauts aboard the International Space Station (ISS) tested a new Japanese robotic arm for the first time Saturday as they passed the halfway mark of their two-week construction flight.

?The week has gone way too fast,? Discovery shuttle astronaut Karen Nyberg said in a series of televised interviews.

NASA?s space shuttle Discovery launched toward the station on May 31 to deliver Japan?s $1 billion Kibo science laboratory, a tour bus-sized module that sports its own small airlock, two windows and a 33-foot (10-meter) robotic arm.

Nyberg and Japanese astronaut Akihiko Hoshide flew the arm through a slight move today to clear space for astronauts to work near it during a Sunday spacewalk.

?It?s a big milestone, we have our own house here now,? Hoshide told reporters of Kibo today. ?And it?s bigger now so people can start doing some science here.?

Astronauts delivered the 37-foot (11-meter) Kibo laboratory earlier this week and attached its storage attic, a small rooftop module, on Friday. They plan to conduct more robotic arm tests and reopen the storage room on Monday.

Tomorrow, spacewalkers Mike Fossum and Ron Garan plan to venture outside the space station to replace an empty nitrogen tank serving the outpost?s cooling system and inspect a massive port-side gear. The gear rotates the station?s port solar wings like a paddlewheel to track the sun.

Fossum spotted what appeared to be excess grease on the gear?s main metal ring during a Thursday spacewalk and photographed areas that may contain minor bits of debris, NASA officials said.

?It really looks to me like a little bit of grease,? Fossum told reporters today.

Engineers hope Fossum can collect samples of the stuff to aid ongoing analysis and repair efforts with a similar gear on the station?s starboard side that has been damaged by metal grit contamination.

Sunday?s spacewalk will mark the third for Discovery?s seven-astronaut crew and the final planned excursion for the shuttle?s 14-day mission. The shuttle is scheduled to undock on Wednesday and land on June 14.

?The mission is going great,? said Discovery commander Mark Kelly, adding that Japan?s Kibo laboratory is nearing full activation. ?It?s getting close to being fully functional facility.?

NASA is broadcasting Discovery's STS-124 mission live on NASA TV on Saturday. Click here for SPACE.com's shuttle mission updates and NASA TV feed.