CAPE CANAVERAL - NASA ispoised to pick up the countdown to launch of shuttle Atlantis this week after swappingout two suspect bolts securing a key communications antenna inside theship's cargo bay.
The work, which wasfinished Sunday at Kennedy Space Center's launch pad 39B, put NASA in positionto start a three-day countdown Thursday. Liftoff of Atlantis and sixastronauts remains scheduled for about 4:30p.m. Sunday.
"Everything is lookinggood," said KSC spokeswoman Tracy Young.
Working atop a platform andscaffolding near the top of the shuttle's six-story payload bay, techniciansreplaced two of the four bolts holding the antenna in place with longer bolts.
The engineers had fearedthat the two original bolts were not adequately engaged and that the 304-poundantenna -- located at the forward end of the payload bay -- might break freeduring launch.
In that case, the antennacould have plunged the entire length of the 60-foot-long cargo bay, causingcritical damage to the shuttle and its $372 million payload.
NASA managers ordered thereplacement work Friday. The shuttle's clamshell-like cargo bay doors wereopened that night, and technicians spent the better part of Saturday setting upequipment for the job.
A work platform wasextended into the bay near the top of a towering room that provides access toshuttle cargoes on five levels.
Scaffolding then was builtup on the platform, and the gangplank was fixed atop it so that a technicianwearing safety harnesses could reach the bolts.
The actual replacement workbegan late Saturday and was completed Sunday.
The Atlantis astronauts arescheduled to arrive at KSC Thursday for final launch preparations. They plan todeliver a new central truss segment to the International Space Station.
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