GSAT-6 successfully launched by India
India successfully launched its communication satellite GSAT-6, on 27th August 2015, using its heavy rocket geosynchronous satellite launch vehicle (GSLV-D6). The GSLV rocket, with a cryogenic engine, slung the satellite in a geosynchronous transfer orbit (GTO) from where it would be taken up to its final geostationary orbit. The successful flight of GSLV rocket gives the Indian space programme a much-needed booster as getting the more-efficient cryogenic engine (which provides more thrust for every kilogram of propellant burnt) right is important for its future space programmes. Indian space scientists have spent around two decades in conceiving the cryogenic technology and spent around £48million Rs.400 crore in developing it. The GSAT series of geosybchronous satellites developed by ISRO with an objective to make India self-reliant in broadcasting services. The collection of 10 GSAT satellites, a total of 168 transponders (out of which 95 transponders are leased out to provide services to the broadcasters) in the C, Extended C and Ku-bands provides services to telecommunications, television broadcasting, weather forecasting, disaster warning and search and rescue operations.
The 49.1 metre tall rocket weighing 416 tonnes slung the 2,117 kg GSAT-6 communication satellite in the geosynchronous transfer orbit (GTO) around 17 minutes into the flight.
As the whole mission concluded successfully, ISRO scientists at the mission control centre were visibly happy, back-slapping and hugging each other once the rocket ejected the GSAT-6 satellite into the intended orbit.
Speaking about the launch, ISRO chairman A.S.Kiran Kumar said after his first successful GSLV rocket launch under his leadership, ‘Today’s performance of launch vehicle was normal. The intricacies of cryogenic engine has been understood.’
The Indian space agency flew the GSLV rocket with its own cryogenic engine for the second time after the successful launch of a similar rocket in January 2014 that put into orbit GSAT-14.
This was the second mission of GSLV during the last five years after two such rockets failed in 2010.
The GSLV is a three stage/engine rocket. The core of first stage is fired with solid fuel while the four strap-on motors by liquid fuel. The second is the liquid fuel and the third is the cryogenic engine.
ISRO’s perfection of cryogenic engine technology is crucial making India self-sufficient by launching communication satellites by itself.
Currently ISRO flies its heavy communication satellites by European space agency Ariane.
ISRO officials told IANS earlier that the country pays around £60million, $85-90 million, Rs.500 crore as launch fee for sending up a 3.5 tonne communication satellites excluding the cost of satellite.
The ISRO can send smaller communication satellites – weighing around two tonnes – till such time it gets ready an advanced GSLV variant-GSLV-Mark III- that can lug satellites weighing around four tonnes.
The space agency will be launching satellites like GSAT-7, 9 using a similar rocket.
One of the notable aspect of the successful launch is the rocket’s weight lift capacity. The current GSLV rocket that ISRO flies has a carrying capacity of around 2.2 tonnes.
The GSAT-6 is India’s 25th geostationary communication satellite and twelfth in the GSAT series, including its predecessors were launched by GSLV during 2001, 2003, 2004, 2007 and 2014 respectively.
The satellite which could last nine years, provides communication through five spot beams in S-band and a national beam in C-band for strategic users. The S-Band Unfurlable Antenna of six metre diameter – the largest satellite antenna realised by ISRO. This antenna is utilised for five spot beams over the Indian mainland, which exploit the frequency reuse scheme to increase frequency spectrum utilisation efficiency.