The tentative launch is fixed for 0621 hrs when the improvised PSLV-C11 will soar into the sky from the Satish Dhavan Space Centre (SHAR), the island in Andhra Pradesh facing Bay of Bengal with the sprawling Pulikad Lake separating it from the land on the one side. It will carry the Chandrayaan-1 spacecraft with 11 payloads, including six from foreign countries. The mood among the ISRO scientists is upbeat and nearly 1000-strong experts have worked day and night for the past one year.
All four stages of the 83 metre tall PSLV-C11 is fully integrated at the second launch pad with the spacecraft undergoing final tests a few kilometre away. At Bylalu village, 40 km from Bangalore, ISRO has set up the Indian Deep Space Network, which includes two massive dish antennae, one with 32-metre diameter and other with 18 meter.
This will be the master control facility for Chandrayaan-1 which would be orbiting 100 km above the Moon after it is put into its slot on November 8.
''This mission is very different for ISRO which is making a big leap from the 40,000 km Earth orbit to nearly four lakh km Moon orbit.
''Our aim is to further expand our knowledge about Earth's only natural satellite -- the Moon,'' SHAR Director M Chandra Dathan told the visiting reporters from Bangalore here on Tuesday.
Mr Dathan said a 52-hour count down would begin on October 21 with 32 hours needed to fill liquid propellants and last ten hours to conduct intensive electronic ground station tests. There will be nobody in the six km radius from the launch pad and everything will be remotely controlled. The launch vehicle would be moved to launch pad on October 17.
''We expect the weather to be good. Rains are expected but there is very less chance of a low pressure area forming in the Bay that might affect the launch date,'' Dr M S Prasad, Associate Director of the SHAR said.
The PSLV-C11, the updated version of ISRO's Polar Satellite Launch Vehicle, is the heaviest launch vehicle in its class with a gross weight of 316 tonnes carrying the spacecraft weighing 1,380 kg.
Chandrayaan spacecraft would be mated with the launch vehicle on October 12 or 13 and once it is launched, it would reach the Earth orbit in 1,089 seconds, Mr V K Srivatsav, DGM (Safety), Range operations said.
Many voyages had already taken place with the countries like the US, Russia and China already having scanned the moon's surface through dozens of manned and unmanned missions.
But ISRO thinks this does not mean every important aspect of the moon is known to humans or fully understood by them. On the contrary, there are many secrets which the moon is yet to 'reveal.' Mr Prasad said these concern the origin and evolution of the moon, very detailed understanding of mineralogy of the Moon, abundance of Helium-3, a relatively clean fuel for future nuclear fusion reactors.
''It also appears that there is presence of water ice in the predominately shadow regions of the Moon's polar areas,'' he said.
The primary objectives of the Rs 386-crore Chandrayaan-1 are to expand scientific knowledge about the Moon, to upgrade India's technological capability and provide challenging opportunities for planetary research to the younger generation of Indian scientists.
ISRO intends to achieve high-resolution remote sensing of Moon in the visible, near infrared, microwave and X-ray regions of the electromagnetic spectrum. A 3-dimensional atlas of the lunar surface with chemical and mineralogical mapping of the entire lunar surface is envisaged. The Indian payload include terrain mapping camera, Hyperspectral imager, Lunar laser ranging instrument, high energy X-ray spectrometer and Moon Impact Probe (MIP). The last would crash land on the Moon's surface and through this prove ISRO intends to qualify some of the technologies related to future soft landing missions.
MIP helps scientific exploration of the Moon at a close distance.
It was developed by ISRO's Vikram Sarabhai Space Centre in Thiruvananthapuram.
The foreign payloads include Imaging X-ray spectrometer and Smart near Infrared Spectrometer, Sub kiloelectronvolt Atom Reflecting Analyzer, all from European Space Agency, Bulgarian Radiation Dose Monitor, Mini Synthetic Aperture radar built by Johns Hopkins University in the US and Moon Mineralogy Mapper. The last two were developed in association with NASA.
Mr Dathan said when the spacecraft is launched from the SHAR it would first move to highly elliptical transfer orbit around the Earth.
After circling the Earth in its transfer orbit for a while, Chandrayaan-1 will be taken into more elliptical orbits by repeatedly firing its liquid apogee motor and the space craft will be ultimately maneuvered to the Moon following a path called Lunar Transfer Trajectory which lines 3.87 lakh km from the Earth.