Weather improves for Friday's shuttle launch

By Irene Klotz

CAPE CANAVERAL, Florida (Reuters) - The space shuttle Atlantis and its hail-scarred fuel tank escaped the worst of severe weather that socked Central Florida overnight and now faces an even rosier forecast for liftoff on Friday, NASA officials said.

A storm that passed south and west of the Kennedy Space Center where Atlantis is being prepared for launch dropped hailstones as big as three-quarters of an inch on West Melbourne, shuttle meteorologist Kathy Winters said on Thursday.

But that was far away from the shuttle's seaside launch pad, sparing Atlantis a repeat of the pummeling it received from a hailstorm in February that pushed back the spacecraft's mission to the International Space Station by three months.

That late-February storm damaged the shuttle's fuel tank, forcing NASA to repair it. Its surface looks pockmarked now, as the newly applied insulation foam has had less time to oxidize and turn yellow under Florida's bright sunlight.

"After many months of hard work, Atlantis is finally ready to fly," said Stephen Payne, a shuttle launch manager.

The outlook for an on-time launch at 7:38 p.m. EDT (2338 GMT) Friday improved slightly, with forecasters now predicting an 80-percent chance of clear skies. Wednesday's forecast was for a 70-percent chance of acceptable weather.

The shuttle will be delivering a huge new section of the International Space Station's exterior truss. The component includes two new solar wing panels and a rotary joint so the wings can track the sun and provide electricity to the station.

The shuttle crew includes two pairs of spacewalkers to handle the installation and to fold up an older solar wing panel that will be moved to a new location next year. The mission is scheduled to last 11 days, but could be extended to 13 days if the crew runs into problems retracting the old solar wing.

The last crew to fly to the station conducted similar work and ended up having to make an unplanned spacewalk to free a jammed wing, using up one of the extra day's worth of fuel and oxygen NASA builds into shuttle missions in case bad weather prevents the spacecraft from landing.

Atlantis' flight is the first of four planned for the year and the 118th in the shuttle program.

The agency has 15 more flights after Atlantis' to complete station construction, deliver spare parts and make a final servicing call to the Hubble Space Telescope. The shuttle fleet is scheduled to be retired in 2010.