India on Friday moved a step closer to launch its maiden unmanned moon session when the lunar spacecraft Chandrayaan-I was mated with the polar rocket which is set to blast off on October 22 from the Sriharikota spaceport.

Gearing up for the final countdown, Space officials said all operations for the mission are progressing satisfactorily and barring a cyclone threat the Polar Satellite Launch Vehicle(PSLV-C11) will keep the date with the country's historic mission on October 22 at 6.20 am.

"The heat-shield closing operations around the spacecraft has been completed. Integrated test of the homegrown launch vehicle (PSLV-C11) is progressing satisfactorily for the launch on October 22 at 0620 hours", ISRO spokesperson S Satish told PTI in Bangalore.

Satish said the 52-hour countdown for the blast-off from the Satish Dhawan Space Centre in Sriharikota, 100 km from Chennai, is expected to commence in the early hours of October 20.

The Centre's Associate Director Dr M Y S Prasad said "the next stage is to shift the 1,300 kg spacecraft to the launch pad and it will be done either this evening or Saturday

morning".

Prasad said that a series of tests would be conducted before the launch. "After conducting a series of tests, the launching would be as per schedule on October 22 morning," he

told PTI in Chennai over phone from Sriharikota.

Indian Space Research Organisation Chairman G Madhavan Nair told PTI "right now, people are working round-the-clock. There is a lot of excitement but at the same time lot of apprehension also".

Space officials said the mission would not be affected by rains which is likely due to the North East monsoon. "Rain does not matter. The launch vehicle is water-proof. Even if

the vehicle gets drenched in the rain, we can still launch it".

However, the mission may have to be rescheduled in the event of a cyclonic threat, they added.

The space centre has set up a seven-member team of experts to monitor the weather conditions over the next six days. "They have different means of forecasting the weather

such as computer models, global observation and domestic Met department observations. We will take appropriate decision before the launch", the officials added.

According to officials, the Chandrayaan-I spacecraft would have a total of 11 payloads. All these payloads have a set of parameters, which have to be monitored right from the

basic battery voltage.

They said the experts will use computer and watch the variation of various parameters under different test conditions.

Chandrayaan-1, India's first space mission beyond the the earth's orbit, aims at expanding scientific knowledge about the moon, upgrade India's technological capability and provide challenging opportunities for planetary research to the younger generation of Indian scientists.

These well-defined objectives would be achieved through high-resolution remote sensing of moon in visible, near infrared microwave and x-ray regions of the electromagnetic spectrum.

India's most ambitious space mission to date would undertake comprehensive mapping of the Moon [Images] for the first time in the world. Earlier missions to moon by some other countries were aimed at specific regions or looked at only certain aspects.