The nation's first moon orbiter is scheduled to blast off at around 6 PM tomorrow from the Xichang Satellite Launch Center in southwest China's Sichuan Province.

"It will be launched between October 24 and 26 and our first choice is around 6 PM on October 24," Li Guoping, spokesman for the China National Space Administration, said Monday.

The launch window is about 35 minutes; and similar slots are available on Thursday and Friday, he said.

The circumlunar satellite, named Chang'e I after the legendary Chinese fairy who flew to the moon, and the Long March 3A carrier rocket have passed all pre-launch tests and have been transported to the launch site.

The lunar orbiter is expected to enter the Earth-moon transfer orbit on October 31; and the moon's orbit, 380,000 km from Earth, on November 5.

The satellite will relay the first pictures of the moon in late November and will continue scientific exploration for a year.

The orbiter will execute a series of projects including the capture of 3-D images and analysis of the distribution of elements on the moon's surface, according to the spokesman.

"Experts from foreign space agencies have been invited to watch the launch at the site," he said.

Work will start this morning to inject conventional fuel into the carrier rocket, which will last about 6 hours, said a senior engineer surnamed Cheng at the launch center.

Liquid oxygen and liquid hydrogen, both non-polluting and high-efficient fuels, will be injected around noon tomorrow, he said.

Li, an engineer who has been working at the center for more than two decades, sounded confident about the launch. "There has been no launch failure in Xichang since 1997, and all the past 14 launches of the Long March 3-A were successful."

But he added that weather is a factor that might influence the launch.

The sky in Xichang finally turned blue and the sun shone brightly Monday after more than 10 days of rain. Local meteorologists forecast clear or cloudy skies till Saturday.

But if the launch cannot be carried out for any reason before Friday, the lunar orbiter will have to wait till next April for a suitable launch window to blast off, according to Cen Zheng, chief commander of the carrier-rocket system.

Initiated in January 2004, the moon exploration project has three stages - "Circling the moon, Landing on the moon and Return to Earth".

The latter two involve landing an unmanned rover on the moon around 2012; and bringing back lunar soil and rock samples around 2017, according to earlier reports.

As the initial phase of the lunar probe program, the orbiting mission will "lay the technical foundation" for later stages of development, said Li.

If successful, the mission will become the third milestone in China's space achievements after manned flights in 2003 and 2005.

(China Daily October 23, 2007)