China's second unmanned lunar probe, Chang'e II, is scheduled to blast off at 6:59:57 p.m. Friday from the Xichang Satellite Launch Center (XSLC) in southwest China's Sichuan Province, the XSLC authorities announced Friday.

The following are some facts and figures:

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.

Chang'e II 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 satellite weighs 2.48 tonnes.

The designed life of Chang'e II is six months, compared with one year for Chang'e I.

The spatial resolution -- the distance between two points that an imaging system can distinguish -- of the newly-developed camera carried by Chang'e II will be around 10 meters, compared with 120 meters for that on Chang'e I.

The launch vehicle for the satellite will be China's Long March 3C rocket, which is 54.84 meters long and with a lift-off weight of 345 tonnes. The delivery capacity of the rocket is 3.8 tonnes.

The rocket will carry Chang'e II to a trans-lunar orbit, which has an apogee of about 380,000 kilometers from the earth, and then the satellite is expected to take about 112 hours, or nearly five days, to arrive at its lunar orbit. Chang'e I took 12 days.

Chang'e II will orbit 100 kilometers above the moon, compared with 200 kilometers for Chang'e I.

Total expenditure for the Chang'e II mission is about 900 million yuan (US$134.33 million).

(Xinhua News Agency October 1, 2010)