Countdown starts for Saturday space shuttle launch

CAPE CANAVERAL, Florida (Reuters) - Countdown clocks at the Kennedy Space Center in Florida began ticking on Wednesday for Saturday’s launch of space shuttle Endeavour on a mission to deliver a porch to the International Space Station.

The space shuttle Endeavour sits on launch pad 39B as the sun rises after rolling out from the vehicle assembly building at the Kennedy Space Center in Cape Canaveral, Florida in this April 17, 2009 file photo. Countdown clocks at the space center began ticking on Wednesday for Saturday's launch of Endeavour on a mission to deliver a porch to the International Space Station. REUTERS/Scott Audette

The platform will complete Japan’s elaborate three-part Kibo laboratory complex, the station’s newest and largest module.

“This has been a long journey for us and our Japanese colleagues,” said Scott Higginbotham, who oversees station payloads at NASA’s Florida launch site.

For about six years, Japanese space agency technicians have worked side-by-side with NASA personnel in Florida to prepare Kibo. The first two sections of the lab were launched last year.

The team, which peaked at about 40 to 50 people, will be returning to Japan after Endeavour’s launch.

The shuttle and its seven-member crew is scheduled to lift off at 7:17 a.m. EDT on Saturday for a 16-day mission.

The astronauts plan to conduct five spacewalks to hook up Kibo’s new porch, replace batteries on one of the station’s solar panel wings and to position spare parts on platforms outside the station.

The porch is a platform for experiments that require direct exposure to space.

“We are so ready to go, we just can’t wait,” Thomas Marshburn, one of Endeavour’s four rookie astronauts, said after the crew arrived in Florida for final launch preparations.

NASA hopes to get Endeavour on its way to the station by June 15 so it can proceed with launch of a lunar probe that is expected to map the moon’s surface in preparation for a human landing in 2020.

Both the shuttle and the Lunar Reconnaissance Orbiter’s launch vehicle use safety and support services provided by Cape Canaveral Air Force Station, which needs two days to configure equipment for different rockets.

NASA has said it will delay Endeavour’s flight to allow LRO a chance to launch on June 17 if needed.

The U.S. space agency wants to complete space station construction by the end of next year and retire its three-ship shuttle fleet so it can shift funds toward developing a new capsule that can travel beyond low-Earth orbit.

NASA has eight shuttle missions remaining on its schedule.

Meteorologists on Wednesday predicted nearly perfect weather conditions for Saturday’s launch attempt.

Editing by Jim Loney; Editing by Eric Walsh