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Discovery liftoff delayed for 5th time

(Agencies)
Updated: 2009-03-12 11:08

CAPE CANAVERAL, Florida  – The launch of the US space shuttle Discovery was postponed Wednesday just hours before liftoff after NASA engineers found a gas leak in the filling system for its external tank.

The US Space Shuttle Discovery sits on the launch pad March 11, 2009 at Kennedy Space Center in Florida. [Agencies]

NASA spokesman Allard Beutel said the shuttle's mission towards the International Space Station, with a Japanese astronaut among its seven crew, was delayed for at least 24 hours after the leak of highly flammable hydrogen gas was discovered.

"The launch was scrubbed at 02:37 pm (1837 GMT) for at least 24 hours ... so we won't launch tonight," Beutel said.

The leak was discovered after NASA engineers began filling the Discovery's external tank at noon (1600 GMT). The leak was found on the side of the tank, said another spokesman John Yembrick.

The last-minute hitch came after mission managers at the Kennedy Space Center in Cape Canaveral, Florida, earlier said it was all go for the planned 9:20 pm (0120 Thursday GMT) launch.

The shuttle's crew arrived at the Kennedy Space Center on Sunday evening to prepare for their 14-day mission to deliver and install a fourth pair of solar panels to the International Space Station.

The panels are to supply power for onboard laboratories and more power for the station's crew, which will double from three to six in May.

Installing the panels, the final piece of a 100-billion-dollar project, is to take a two-astronaut team four space walks of more than six hours each to complete, NASA said.

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The pairs of solar panels, containing 32,800 solar cells, are each 35 meters long once in place. And the final array, once in place, should boost power available to the ISS to 120 kilowatts from the current 90.

The launch, originally set for February 12, has now been delayed five times, the four previous postponements being due to problems with control valves, which channel gaseous hydrogen from the shuttle's three main engines.

Three of the valves were replaced with newer ones. NASA engineers said the delays were implemented as a precaution to test the valves, which had come under close scrutiny after a valve aboard space shuttle Endeavour was found to be damaged during its mission to the space station in November.

Discovery's astronauts include Koichi Wakata of the Japan Aerospace Exploration Agency, who is to become the first Japanese station crew member.

After Discovery finally docks at the ISS, Wakata is to stay aboard the station, while US astronaut Sandy Magnus -- who arrived at the ISS aboard the shuttle Endeavour in November 2008 -- will return home.