CAPE CANAVERAL, Fla. -- Space shuttle Discovery's astronauts overcame navigation equipment trouble and arrived at the international space station Friday for a week of demanding construction work.
Commander Brian Duffy had to execute the 240-mile-high rendezvous without the use of the shuttle's radar, which broke on Thursday. Instead, he relied on a star-tracking system and handheld lasers operated by his crew.
It was the first time in almost 20 years of space shuttle flight that a shuttle closed in on another spacecraft without the use of the main antenna for radar, NASA said.
Discovery latched onto the station right on time as the two spacecraft soared over Russia at 17,500 mph. It was a smooth and fuel-efficient docking despite the antenna failure, which knocked out both the radar and TV links.
"Excellent rendezvous," Mission Control informed Duffy.
Sequential snapshots of the final approach and linkup were beamed down via a much slower antenna on Discovery, and a camera on the space station provided grainy, black-and-white views.
It was small consolation to a space agency that had hoped to reap huge public-relations benefits from stunning TV scenes of the ambitious construction mission. The lack of live, continuous video will be especially acute during the four spacewalks that get under way beginning Sunday.
Throughout Thursday and again Friday morning, flight controllers and the astronauts tried to fix Discovery's high-speed relay system. They finally gave up and declared the 3-foot dish antenna unusable for the rest of the 11-day mission.
Flight director Chuck Shaw said the problem seems to be with an electronics component. Engineers will not know for sure what broke until the shuttle returns to Earth and the antenna system is inspected.
All necessary messages and files were getting through via Discovery's slow antenna. "It's like working with a slower modem," Shaw explained.
Once the two spacecraft were tightly joined together, the astronauts ventured into the space station to collect air samples and drop off a few supplies.
Discovery is carrying two new pieces for the still-uninhabited space station. An aluminum framework will be installed on Saturday.
Japanese astronaut Koichi Wakata will use the shuttle robot arm to lift the boxy 18,000-pound truss from Discovery's cargo bay and attach it to the space station. The truss holds four motion-control gyroscopes and two antennas, and will serve as the base for solar wings to be installed by the next shuttle crew.
On Monday, Wakata will crank up the robot arm again to move a docking port from Discovery to the space station. The port will be used for future shuttle visits.
Two teams of spacewalking astronauts will make all the necessary connections between the new segments and the space station.
All the work must be completed before the space station's first residents can move in. NASA astronaut Bill Shepherd and his two-cosmonaut crew are scheduled to lift off Oct. 30 aboard a Russian rocket. They will spend four months on the station.
Discovery will remain attached to the space station until Oct. 20. The shuttle is scheduled to return to Earth on Oct. 22.
|On the Net:|