China's space technicians are preparing for the first major challenge faced by lunar satellite Chang'e 1 when the Earth eclipses the sun and blocks the supply of solar energy next Thursday.

Scientists have had to redirect the orbit of the satellite, which has been operating for 100 days, in order to shorten the time it is out of direct sunlight.

The satellite, which has completed 1,135 orbits of the moon, would have been hidden from the solar rays for three to four hours causing a possible power shortage, said Zhu Mincai, director of the Beijing Aerospace Control Center.

The adjustment would shorten the time to two hours, ensuring enough solar power for the orbiter, said Zhu.

The eclipse will coincide with this year's traditional Chinese Lantern Festival when the moon will be wholly shadowed by the Earth.

Some facilities would be temporarily switched off during the eclipse, but this would have no major impact on the satellite's operation, said BACC scientist Liu Congjun.

The satellite will perform a second orbital adjustment during another eclipse in August.

The 2,350-kilogram satellite carrying eight surveying facilities aims to make a three-dimensional survey of the moon's surface.

It will also analyze the abundance and distribution of elements on the lunar surface, investigate the characteristics of the powdery soil layer on the surface, and explore the environment between the Earth and the moon.

It is the first step in China's three-stage moon mission.

(Xinhua News Agency February 16, 2008)