Bangalore (PTI): India's first unmanned mission to the moon--Chandrayaan-1-- can be launched in September at the earliest, a top official said, but the exact date for the "unique" exploratory flight will be announced next month.

"There are a lot of expectations from the mission. It is going to be a unique mission in which you will get the total mapping of the moon, which does not exist today," Dr G Madhavan Nair, Chairman of the Indian Space Research Organisation(ISRO) told reporters on Thursday.

Regarding the exact date of launch of the 100 million dollar mission, Nair said "the launch date will be announced next month. September is the earliest."

The lunar craft will not be landing but will travel in a polar orbit around the moon--100 km above the lunar surface-- and pay special attention to gathering data on the polar icecaps that may contain traces of water. The spacecraft is expected to take at least two years to cover the entire lunar surface.

"We are trying to look for rare elements on the surface of the moon. The information will help us in further exploration", Nair said.

On any proposed joint venture with a foreign partner to tap helium on the moon, he said "Right now it is only a preliminary concept stage. Once we know that helium is present, we can go to the next stage".

He said the second Mission in 2012 would have a Rover and and Lander. "It will go down to the moon's surface and pick samples, analyse and send back data".

Former President A P J Abdul Kalam said the moon mission would be a platform to go to Mars. "In future we need to see earth-moon-mars as a single complex for humanity." The moon mission has tremendous potential in the context of there being a presence of helium, which can be tapped for power generation.