Space shuttle Endeavour gets back to work

CAPE CANAVERAL, Fla, Aug 8 (Reuters) The US space shuttle Endeavour was due to blast off from Florida today 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 the US space agency plans this year as it presses to finish construction of the 0 billion space station before the three remaining US shuttles are retired in 2010.

Florida's weather, often marked by afternoon thunderstorms during the state's steamy summer, was expected to cooperate, with an 80 percent chance of clear skies for the 6:36 p.m. local time (0406 hrs) launch, NASA said.

With no technical issues or weather concerns, NASA managers cleared the newly refurbished shuttle for fueling, which began around 8:30 a.m. local time (1800 hrs). Filling the ship's tanks with 500,000 gallons (2.3 million litres) of supercold liquid oxygen and liquid hydrogen was expected to take about three hours.

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.

Endeavour has not flown since before the February 1, 2003, Columbia disaster, in which seven astronauts were killed when their spacecraft disintegrated on re-entry into the atmosphere.

NASA and Columbia's crew had not been aware that a falling chunk of insulation foam had knocked a hole in the ship's protective heat shield during launch. The agency now monitors liftoffs with dozens of cameras and shuttle crews scrutinize their ship's heat-resistant tiles when they reach space.

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.

CIVILIANS WERE BANNED But it is the crew that has fallen under the spotlight, partly because the five-man, two-woman team includes former elementary school teacher Barbara Morgan.

Morgan trained 22 years ago 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 January 28, 1986, when a booster rocket blew up.

Civilian fliers were banned from shuttles after the Challenger disaster and Morgan joined the astronaut corps in 1998.

The astronaut corps itself is also under some 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,'' Endeavour Commander Scott 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.

REUTERS GT KN1931