INTRO: The U-S space shuttle Discovery is closing in on the international space station for a rendezvous later today [Friday, 1:45 p.m. EDT]. But Discovery will probably have to locate the station without radar, because a shuttle antenna has stopped working. V-O-A Science Correspondent David McAlary reports.

TEXT: The shuttle is getting closer to the space station with each orbit of the Earth. But the seven crewmembers may have to approach the outpost without use of the main shuttle antenna. It beams shuttle television to Earth and doubles as a radar tool to help fix the station's position in the shuttle's monitors.

The lead shuttle flight director, Chuck Shaw, says the loss of radar is not critical for docking or any other shuttle activity. There are backup navigation devices, including a pair of star trackers that can locate the station by sensing its lights. Mr. Shaw says when the two spaceships get very close, the astronauts view the docking target through the shuttle's television cameras and measure distance with tools emitting laser beams that reflect back to Discovery.

/// SHAW ACT ///

People want to make it into a big deal. From an operations impact standpoint, it's not a big deal. I would put it in the irritant category more than an impact category, and that's true.

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Mr. Shaw says the key impact from losing the antenna signal is the lack of live mission video for journalists and the public. Viewers may not get to see Japanese crewman Koichi Wakata attach a docking port and a truss to the station with the shuttle crane or watch astronauts take four spacewalks to connect them electronically to the outpost.

The docking port will be another entrance to the U-S module onto which future shuttles can lock. The truss is a latticework girder on the U-S cabin that houses positioning gyroscopes and communications equipment. Solar power panels will eventually be attached.

Astronaut Wakata practiced operating the crane Thursday, then -- with shuttle commander Brian Duffy -- received good wishes by radio from Japanese Prime Minister Yoshiro Mori and Science and Technology Minister Tadamori Oshima.

Mr. Wakata said he planned to dine on rice and miso soup after the conversation and sent greetings to his mother back home.

/// WAKATA ACT ///

I would like to thank her for the support she has given me and please convey to her that I am working hard in space.

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