CAPE CANAVERAL, Fla. - Space shuttle Discovery's astronauts successfully attached a new segment to the international space station on Saturday despite a short circuit that knocked out critical visual equipment.
The shuttle's robot arm operator, Japanese astronaut Koichi Wakata, installed the girderlike truss after more than three hours of anxious delay.
Flight controllers applauded when the pieces finally came together. ''Good work,'' Mission Control said.
The electrical short not only dragged out the first construction job of the mission, it made it more difficult. The short occurred as Wakata was preparing to latch onto the truss in the shuttle cargo bay and lift it onto the space station.
''What timing, huh?'' observed commander Brian Duffy.
It was the second equipment problem to strike the mission. The shuttle's main antenna broke without warning last week and forced Duffy to dock with the space station Friday without the benefit of radar, a space shuttle first.
''Unbelievable,'' Duffy said following Saturday's trouble.
The short disabled a computerized vision system and a camera in the shuttle cargo bay. Per Mission Control's instructions, the astronauts quickly replaced electronic components for the vision system. There was nothing they could do, however, about the lost camera.
Once the vision system was restored, Wakata grappled the boxy 18,000-pound truss with the shuttle robot arm. He raised the truss out of the cargo bay and, after a long series of checks, deftly attached it to the space station's Unity module. Sixteen electrically powered bolts drove the two pieces together.
The computerized vision system was crucial since Wakata did not have a direct line of sight from the shuttle cockpit for precise alignment. It's essentially a connect-the-dots system.
Even before Saturday's trouble, astronaut Michael Lopez-Alegria had planned to observe the installation of the truss through a space station porthole. The lost camera made his eyes all the more valuable. He had to use a flashlight to see out the window in the darkness.
The truss, an aluminum framework about 15 feet square, contains four motion-control gyroscopes and two antennas. It will serve as the mount for an electricity-generating solar panel that will be installed in December by the next shuttle crew.
On Sunday, two spacewalking astronauts will go out to connect all the cables between the truss and the Unity module. It is the first of four spacewalks planned for the mission.
And on Monday, a docking port will be attached to the space station, to be used for future shuttle visits.
This is NASA's first space station construction mission since the initial components were launched in 1998. It must be completed before the station's first permanent crew can lift off aboard a Russian rocket on Oct. 30.
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