US space shuttle poised for launch on Friday

CAPE CANAVERAL, Fla., June 8 (Reuters) NASA is finally ready to fly its first mission of the year, with space shuttle Atlantis and seven astronauts scheduled for liftoff today evening from the Kennedy Space Center in Florida.

Meteorologists were predicting clear skies at launch time at 0508 ist with only a 20 per cent chance of a delay due to possible thunderstorms.

Atlantis will deliver two segments of the International Space Station's metal spine. The trusses include a huge pair of solar wing panels and a rotary joint so the wings can track the sun for power.

The Atlantis crew also needs to fold an old panel that will be moved to another location on the station next year.

Today morning, technicians began pumping a half-million gallons (1.89 million litres) of cryogenic liquid oxygen and liquid hydrogen into the shuttle's fuel tank, which bears the scars of a three-month repair job to fix hail damage.

The shuttle was pummeled by hailstones during a freak storm on February. 26. At the time, NASA was targeting Atlantis' launch for mid-March.

The US space agency fixed thousands of dings, dents and gouges in the tank's insulating foam. The patched areas are clearly visible, as the new foam has not had time to oxidize and turn orange-yellow in the sun like the rest of the tank.

Despite the repaired foam's appearance, NASA managers are confident it will hold during Atlantis' climb into orbit.

Since the deadly 2003 shuttle Columbia accident, NASA has been particularly sensitive to issues involving fuel tank foam.

During liftoff, Columbia's tank shed a piece of insulation that smashed into the wing and broke a hole in the heat shield.

The shuttle was destroyed as it attempted to fly through the atmosphere for landing 16 days later, killing all seven astronauts aboard.

The accident put NASA three years behind schedule in finishing the space station.

The agency needs to fly at least 13 more missions to deliver all of the major components before the shuttle fleet is retired in 2010. It also plans two flights to stash spare parts on the station and a last service call to the Hubble Space Telescope.

During NASA's last shuttle mission in December, astronauts ended up having to make an unplanned spacewalk to coax a jammed panel into a storage box.

This time, NASA has backup plans and two extra days of fuel and supplies in case the mission has to be extended beyond the planned 11 days.

REUTERS SBC RK2237