Preparations for China's second unmanned lunar probe, Chang'e II, are almost complete at the Xichang Satellite Launch Center (XSLC) in southwest China, and the satellite is ready for a Friday launch, based on satisfactory weather forecasts.

Weather will be the only question for Friday as the rocket's first and second stage boosters were fueled with conventional propellants Thursday, said authorities with the XSLC.

Li Shangfu, Chief Director of the XSLC, said the center's Thursday weather forecast for Oct. 1, the first launch window, predicted light rain and very limited chances that thunder and lightning would occur from the time of the rocket fueling to an hour after the launch window.

Further, the launch is not likely to be influenced by the high-altitude winds and the electric field on the ground, he said.

The launch center will hold a meeting at 10:30 AM Friday to decide whether to begin the final stage of fueling of the Long March 3C rocket, the last procedure before the launch, based on weather conditions, said Li.

Once the fueling of the rocket's third stage booster begins, the launch of the satellite will be "irreversible" and occur in eight hours, he said.

With the help of radar and satellites, weather forecasts at the XSLC are 80 to 90 percent accurate for no more than 48 hours, and for weather conditions within four hours they can be over 90 percent accurate, said Jiang Xiaohua, a meteorological expert at the center.

The rocket will carry the Chang'e II to a trans-lunar orbit, and then the satellite is expected to take about 112 hours, or nearly five days, to arrive at its lunar orbit for a six-month mission.

The lunar probe will test key technologies and collect data for future landings of Chang'e III and Chang'e IV, and provide high-resolution photographs of the landing area.

Chang'e II was built as an alternative to Chang'e I, which was launched in October 2007 and maintained a 16-month lunar orbit. The series of Chang'e probes is named after a legendary Chinese moon goddess.

(Xinhua News Agency October 1, 2010)