Shanghai will be the headquarters of the satellite positioning equipment used to track the country's first lunar orbiter, due to be launched next April, officials said on Monday.

The lunar orbiter positioning system uses four radio telescopes -- in Shanghai, Beijing, Kunming, capital of southwest China's Yunnan Province, and Urumqi, capital of Xinjiang Uygur Autonomous Region in the northwest.

But it is in Shanghai that the data will be collected and calculated.

In a rehearsal this month, China, in cooperation with the European Space Agency, used the array to track the Smart-1 - an ESA lunar orbiter that has been orbiting the moon since November 2004.

According to the Shanghai Astronomical Observatory, the test was very successful and was an important warm-up ahead of the launch of its own orbiter.

"The orbit position of lunar probe is key to guaranteeing its normal functions in space, such as taking quality pictures of the moon," Fu Chengqi, a researcher with the Shanghai Astronomical Observatory, said yesterday.

In Shanghai, the positioning was achieved with a radio dish atop Sheshan Hill in Songjiang District.

The dish collects the radio waves from the lunar orbiter -- about 400,000 kilometers away -- and records the time they take to make the trip.

At least three dishes on the ground are needed to locate the lunar orbiter but the more that are used, the more precise the probe positioning will be, officials said.

China has finished the plan of its first moon probe and the orbiter, called Chang'e-1, will be launched next April.

Chang'e is a beautiful goddess living on the moon in Chinese mythology.

The satellite, part of a three-stage program, will be followed by the landing of an unmanned vehicle on the moon in 2010. Samples of lunar soil will be collected in the final phase in 2020.

The satellite project was designed to obtain three-dimensional images of the lunar surface, analyze elements and materials on the surface and probe the depth of the lunar soil.

(Shanghai Daily June 13, 2006)