They took care of all the preliminaries, removing covers and disconnecting cables. The astronauts then handed the job to the robot arm-operators inside the shuttle, who lifted the lab out of Discovery's payload bay and attached Kibo to the space station.
The Japanese lab is bigger and more sophisticated than the two other labs at the space station. (The European lab Columbus was attached in February.)
It sports a hatch to the outside and a robot arm for sliding out science experiments. A smaller arm will arrive next spring, along with an outdoor "porch" for holding the experiment packages.
The first part of Kibo—essentially a storage shed—was delivered by the last shuttle crew in March. The astronauts aboard the shuttle and station, which are currently linked, will attach the shed to the lab on Friday.
The lab work was just part of Tuesday's spacewalk, the first of three planned for Discovery's nine-day space station visit.
Fossum and Garan also helped remove a 50-foot (15-meter) shuttle inspection beam from the space station and get it back to Discovery.
They also worked on the station's jammed solar wing rotating joint. Fossum tried out some cleaning techniques on the joint, which is gummed up with metal shavings, while Garan put in a new bearing.
The joint has been used only sparingly since last fall, hampering energy production. NASA still does not know where the grit came from or how best to deal with the problem.
As for Discovery, the photos taken by the space station residents just before Monday's linkup uncovered just four small areas of tile damage on the shuttle's belly. The damage is so slight that no detailed inspection will be required, said LeRoy Cain, chairman of the mission management team.
