Wednesday, December 10, 2014

GSAT-16 an more....

India has a new bird in the sky — the communication satellite GSAT-16 that was successfully launched aboard Europe’s Ariane 5 rocket in the early hours of Sunday. GSAT-16 has 48 transponders, the largest number thus far on a communication satellite built by the Indian Space Research Organisation. It will join a constellation of 10 satellites that form the Indian National Satellite (INSAT) system. Its transponders, operating in various frequency bands, will provide much-needed augmentation of the existing 188 transponders on the INSAT system that broadcast television programmes, provide educational and tele-medicine services, carry telephone conversations, and relay data. In addition, close to 95 transponders have been leased on foreign satellites, principally to meet the needs of Direct-To-Home (DTH) television channels. Vikram Sarabhai, who founded the country’s space programme, had the farsightedness in the 1960s itself to recognise how important communication satellites and the services they provide would be to a developing nation. It was a vision that his successors turned into reality, with the first of the indigenously-built INSAT satellites being launched in July 1992.
After the Polar Satellite Launch Vehicle (PSLV) became available in the mid-1990s, the country has not had to look abroad to launch its remote sensing satellites. That transition has yet to happen with communication satellites. The current Geosynchronous Satellite Launch Vehicle (GSLV) has hitherto been trouble-prone, and the version equipped with an indigenous cryogenic stage replacing an imported Russian one made its first successful flight only in January this year. Even if the GSLV becomes a reliable launcher like the PSLV, it can only carry communication satellites weighing up to about 2.2 tonnes. ISRO has already launched considerably heavier communication satellites on the Ariane 5, including the GSAT-16 that weighs close to 3.2 tonnes. Launching these satellites abroad is expensive. The price tag for the GSAT-16 comes to about Rs.900 crore. Of this, the foreign launch costs come to around Rs.560 crore — not including insurance. Had the next-generation GSLV Mark III, which can take four-tonne communication satellites, been operational, that launch might have cost only about half as much. But the cryogenic engine for the upper stage of the Mark III is still being developed. The rocket’s first experimental launch, scheduled for later this month, will therefore be a suborbital one to test its flight characteristics through the atmosphere. ISRO expects to have the Mark III’s cryogenic engine and stage ready in two years’ time. The sooner that happens, the better.


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