Bangalore, July 24 - India will soon design and develop its heaviest communications satellite GSAT-11 to provide advanced telecom services from 2011-12, a senior official of the Indian Space Research Organisation (ISRO) said here Friday. At 4.5 tonnes, it will weigh more than twice as much as the biggest Indian satellite in orbit now.

'Activities to design and develop GSAT-11 will start immediately, as the project has been cleared by the government at a cost of Rs.5-billion (Rs.500 crore),' ISRO Director S. Satish said.

The advanced communications technology satellite will be launched in mid-2011 on board the Geo-Synchronus Satellite Launch Vehicle (GSLV-Mark III) from ISRO's spaceport at Sriharikota, about 80 km north-east of Chennai.

'The satellite will be designed at our satellite centre in Bangalore, payloads consisting of 40 transponders in Ku/Ka band will be built at the space applications centre in Ahmedabad and the 630-tonne rocket (GSLV-Mark III) will be rolled out from the liquid propulsion systems centre in Thiruvananthapuram,' Satish told IANS.

The indigenously developed GSAT series of satellites are aimed at revolutionising communications, spanning digital audio, data and video broadcasting. The earlier versions of GSAT such as GSAT-1 and GSAT-2 were designed with two S-band and three C-band transponders.

'With 16 high capacity multi-beams in Ku/Ka band, GSAT-11 will provide much faster uplinks for a host of communications and broadcasting services, including direct-to-home (DTH television). With a dry mass of 2.1 tonne, the spacecraft will provide 10 GHz of bandwidth, which will be equivalent to about 220 transponders of 36 MHz,' Satish pointed out.

The advanced satellite will employ a new 1-4K Bus (computer network). It will be configured with two-sided large solar array panels generating 11 KW of power.

In the run-up to GSAT-11, the space agency is scheduling the launch of other communications satellites in the GSAT series over the next two years.

'The two-tonne GSAT-4, slated for launch by this year on board GSLV-Mark II, will have a communication payload comprising multi-beam Ka-band pipe and regenerative transponder and navigation payload in C, L1 and L5 bands,' Satish said.

GSAT-4 will also carry a scientific payload, Tauvex, consisting of three ultra violet (UV) band telescopes developed by Tel Aviv University and Israel space agency for surveying a large part of the sky in the 1,400-3,200 Angstrom wavelengths.