India plans to double its annual satellite launches and put into space up to 25 spacecraft in a $2 billion exercise spread over the next five years as it moves to take advantage of booming demand for capacity, top Indian Space Research Organisation officials say.

New Delhi has targeted to boost the number of transponders India currently has from 199 to 500 by the end of the 11th five year plan (March 2012), Secretary in the Department of Space G Madhavan [Images] Nair said.

"On an average, we may have about four to five launches in a year compared to hardly two that we are (currently) doing annually," Nair, also chairman of ISRO and the Space Commission, told PTI in an interview.

"That is one of the major loads not only on ISRO but on industry and other establishments in the country," he said.

ISRO officials estimate the cost involved in building these satellites and launching them in the region of Rs 8,000 crore to Rs 9,000 crore (approximately $2-2.25 billion).

Bangalore-headquartered India's space agency plans to launch as many as 15 INSAT-class satellites and 8-10 remote sensing spacecraft by 2012 as it moves to stay ahead of the demand curve.

On the configuration of bands to be used in the future INSAT-class satellites, Nair said: "We will have to use all the bands because the increase in demand is so much. We have got only limited slots available for us."      

"But primarily, concentration will be in C and Ku bands and marginally we may start using Ka band for high bandwidth and also some capacity in S-band is a must for remote area communication and so on," he added.

According to ISRO, the projected requirement of the number of transponders is 400 by 2012.      

"But we want to build extra capacity. Because in the last plan (10th plan) we had 25 per cent excess capacity than anticipated...they all got consumed in no time," Nair said, adding, "So, the growth pattern in this industry is very large and we want to keep ahead of the requirement."

Meanwhile, ISRO has selected European launcher Arianespace to launch INSAT-4G communication satellite, which is the last satellite that India would launch from foreign soil.

"Yes (it would be the last launch of Indian satellite from foreign soil). By that time, our GSLV-Mk III will be operational and it should be able to take care of any satellite that we will be building," he said.

The 3200-kg INSAT-4G, which will have payloads for communications, broadcasting and weather observation, is slated to be launched towards the end of 2008.

"We have completed negotiations (for INSAT-4G launch) with them (Arianespace) and it's submitted to the government for approval," he said.

INSAT-4G will be the 14th ISRO satellite to use Arianespace, the European launcher. It started with Apple experimental satellite in 1981.

On his thoughts on India becoming totally self-reliant in launching satellites after the INSAT-4G launch, Nair said: "It shows our technical strength."

But the only disappointing part, he said, was that scientists and users do not project their requirements.

"It is only the imagination of ISRO that is put into use. Otherwise, by this time, we would be launching our own satellites in all capacities. But user (community) has also grown much beyond our expectations. But we will catch up," the ISRO chairman added.