Space Shuttle Endeavour Prepares for Launch

The U.S. space shuttle Endeavour was due to blast off from Florida on Wednesday on its first mission in nearly five years.

The space shuttle Endeavour was due to blast off from Florida on Wednesday on its first mission in nearly five years, carrying a former teacher who trained with the ill-fated Challenger crew and gear for the International Space Station.

The mission will be the second of four that NASA, the U.S. space agency, plans this year as it presses to finish construction of the $100 billion space station before the three remaining shuttles are retired in 2010.

Florida's weather, often marked by afternoon thunderstorms during the steamy summer, appeared likely to cooperate. There was an 80 percent chance of clear skies for the 6:36 p.m. EDT/2236 GMT launch, NASA said.

With no technical or weather concerns, NASA technicians filled the newly refurbished shuttle's tank with 500,000 gallons (2.3 million litres) of supercold liquid oxygen and liquid hydrogen.

The shuttle's three main engines will guzzle the propellants in its 8.5-minute climb to orbit. Docking at the space station would take place on Friday if the shuttle is launched on time.

In preparation for launch, the shuttle's five-man, two-woman crew, including teacher-astronaut Barbara Morgan, dressed in bright orange pressurized flight suits and rode a van to the launch pad.

Commander Scott Kelly, who has made one previous flight, was the first to board the shuttle. Morgan was assigned to sit in the middle seat on the lower deck, the same spot where her predecessor sat more than 21 years ago on Challenger.

Endeavour has not flown since before the Feb. 1, 2003, Columbia disaster, in which seven astronauts were killed when their spacecraft disintegrated on re-entry into the atmosphere. A falling chunk of insulation foam had knocked a hole in the ship's protective heat shield during launch.

BRAND NEW SHUTTLE

Endeavour has undergone an extensive overhaul since its last flight in November 2002 and NASA managers say the spacecraft is virtually new. It has a new piece of equipment that can tap into the power grid of the space station and could allow the shuttle to extend its 11-day mission to 14 days.

The primary purpose of Endeavour's flight, which is the 119th in the shuttle program, is to deliver and install a new beam for the station's main support structure, replace a faulty gyroscope needed to keep the outpost positioned properly in orbit and deliver supplies.

But it is the crew that is under the spotlight, partly because it includes former elementary school teacher Morgan.

Morgan trained as the backup to Challenger crew member Christa McAuliffe, a New Hampshire social studies teacher who died along with six astronauts seconds after Challenger's liftoff on Jan. 28, 1986, when a booster rocket blew up.

Morgan formally joined the astronaut corps in 1998.

The corps itself is under scrutiny after allegations last month that a drunken astronaut was allowed to fly on a Russian spacecraft and another almost flew on a shuttle.

"To imply that my crew or I would ever consider launching on our mission in anything but the best possible condition is utterly ridiculous," Commander Kelly wrote in a letter to journalists, denouncing the panel that reported the allegations for posting unsubstantiated opinions.

NASA managers have launched an investigation and vowed to reinforce a 12-hour ban on alcohol before spaceflights.

Endeavour's mission was also clouded by the revelation that a component it is taking to the space station had been sabotaged by a worker at one of NASA's subcontractors. The computer has been fixed and an investigation is under way.