CAPE CANAVERAL, Fla. The crew of space shuttle Discovery added a new segment to the International Space Station on Saturday, despite a delay of more than two hours caused by an electrical failure effecting the shuttle's robotic arm.
Japanese astronaut Koichi Wakata was flexing the 50-foot (15-meter) arm when a short circuit in the payload bay knocked out several systems.
Among them was a computerized system called Space Vision and a television camera mounted in the rear of the shuttle.
Both were meant to help Wakata position a massive Z-1 truss into place on the $60 billion space station.
The crew scrambled around in the cramped orbiter pulling apart cable connections and resetting switches, supplying new power to the vision system.
Power to the television camera could not be restored, so astronaut Michael Lopez-Alegria substituted his own eyes. Posting himself by a portal inside the station, he gave Wakata verbal cues to replace the lost visual ones.
With that, Wakata was able to hoist the 9-ton truss from the payload bay and move it to its permanent berth on the space station's Unity module.
At one point, Flight Director Chuck Shaw spoke to shuttle Commander Brian Duffy and assured him that work would go forward despite the glitch.
"This is a good sim," Shaw said, referring to the mission simulations in which trainers delight in creating problems for the astronauts to solve.
"Unbelievable is a little more like it," Duffy replied.
Once the truss was in place, pilot Pam Melroy sent a computer command that made 16 bolts lock the truss permanently into place.
The Z-1 truss is an inelegant piece of hardware that will become the base of an array of solar paneled "wings" that will eventually reflect enough sunlight to make the station one of the brightest objects in the evening sky.
The truss has four large gyroscopes that will stabilize the space station as it orbits the earth. Earlier space stations, such as the Russian Mir and the American Skylab, used thrusters for stabilization, making fuel consumption a greater worry.
During four upcoming spacewalks, astronauts will connect cables, install additional hardware and position an antenna so the truss will be fully integrated with the rest of the space station and with mission control on earth.
Discovery and its crew of seven docked at the space station on Friday. Wakata is expected to perform a similar task when he lifts a new docking port from the shuttle's bay and positions it elsewhere on Unity.
The television camera won't be needed for that operation, since it takes place on the opposite side of the station.
Instead a pair of spacewalking astronauts will hover outside Unity and help him as needed.
The setback on Saturday was the second notable mishap on the mission although the two apparently were unrelated.
A failure Thursday in the Ku band antenna knocked out radar and Discovery's ability to send television signals to earth. Because of that problem, Duffy had to dock the shuttle to the space station without radar a shuttle first, NASA said.
The mission is planned for 11 days.
The space station is a joint project of the United States, Russia, Japan, Europe and Canada and is scheduled for completion in 2006.
(Reuter)