THIS EARTH will eclipse the Sun in two day’s time. Ironically on ‘Sunday’. But not everyone thinks it will be a Super Sunday.

The team behind China's first lunar probe satellite, Chang'e 1 will be on the edge of their seats. Because this will be a big test of their probe's solar energy capacity. Not so much the ability to convert energy. But to store this precious resource.

They’ve been here before though. The probe was plunged into darkness on February 21, by a full eclipse. It came through that test unscathed, running on battery power for two hours.

Sunday's eclipse will be longer. Chang’e 1 will have to rely on batteries from 3:35 am. to 6:44 am while it’s starved of solar sustenance.

"The moon's shadow, also a signal blind area, could cause a power shortage in freezing temperatures," fretted Wang Sichao, a research fellow with Zijinshan (Purple Mountain) Astronomical Observatory.

In the first eclipse, the boffins took damage limitation measures. They cut corners by changing the satellite’s orbit to limit the time it was in the shade. Some unused functions were powered down too.

For nine months the satellite has been conducting a three-dimensional survey of the moon's surface. So there’s a lot of data to lose. It uses eight different surveying facilities to collate its information.

Though it was designed to last one year, the scientists hope to get another 12 months out of it. (It’d be a shame to waste 2, 350kg of expensive equipment like that)

Though it’s a giant step for mankind, this is but the first step in China's three-stage moon mission, which should conclude with the landing and launch of a rover vehicle around 2012. In the final phase, another rover will land and return to the Earth with lunar soil and stone samples for scientific research around 2017.

But, as the old Chinese proverb says: the hardest part of a 1000 mile journey is the first step. µ