ISRO set to launch GSAT-6 tomorrow, crucial cryogenic engine technology on test

Wednesday, Aug 26, 2015,20:16 IST By metro vaartha A A A

New Delhi/Sriharikota | All eyes will be up in the sky tomorrow as Indian space agency launches its cryogenic engine-fired space vehicle tomorrow for the launch of an advanced communication satellite.
The launch is scheduled at 1652 hrs from the Second Launch Pad at Satish Dhawan Space Centre, Sriharikota, a barrier island in the Bay of Bengal.
For the third time, the Indian Space Research Organisation(ISRO) will be testing the fidelity of its indigenous cryogenic engine in the real-time launch conditions on an Geo-Synchronous Satellite Launch Vehicle (GSLV).
On Monday, the Mission Readiness Review committee and the Launch Authorisation Board of ISRO had cleared the 29 hour countdown for the launch of the GSAT-6 satellite mission for tomorrow.
The mission is in furtherance of ISRO’s efforts to hone its cryogenic engine technology in a 2.5 tonne class category. ISRO has already ground-tested 4 tonne class engine last month which will follow suit once the 2.5 tonne class missions are perfected to zero-glitch.
The cuboid-shaped, 2.117 tonne geostationary communication satellite GSAT-6 is designed to serve as a communication hub for five-spot beam in the S-Band and and a national beam in C-band for strategic users. It has six metre wide unfurlable S-Band antenna, the biggest ever designed by ISRO, for the spot beam over India. The spot beams exploit the frequency re-use scheme to optimise the spectrum utilisation.
The satellite also houses a 70 V bus, flying first time in an Indian communication satellite. Five such satellites were launched by GSLV in 2001, 2003, 2004, 2007 and 2014.
GSAT-6 has its own propulsion system. After its injection into the orbit, ISRO’s Master Control Facility (MCF) at Hassan will take control of the GSAT-6 and will execute the initial orbit raising manoeuvres by repeatedly firing the Liquid Apogee Motor on-board the satellite, careening it into the circular geostationary orbit. After this, the antenna will be deployed and the satellite be stabilised on three axis a finishing touch to an accomplished mission. The mission life is nine years.
GSLV stands out from the Polar Satellite Launch Vehicle(PSLV) for a cryogenic engine in its guts. The PSLV uses hypergolic fuel which is less powerful and needs a bigger tank, a bit unwieldy on compactly crafted space vehicle. Fashioned on French Ariane rockets, the Indian space doctrine toes the same development model of Ariane which graduated from using low-efficiency hypergolic engines to powerfull and less messy cryogenic engines today.
The communication satellites are invariably geo-stationary as, if sighted, they look affixed to a point up there because its movement in the orbit is synchronised with earth revolving at the speed of 1670 km per second along equator from West to East. The speed of the satellite is set accordingly. Sriharikota sits just on the equator, considered next best only to Kennedy Space Center in the US.
Tomorrow’s launch is critical for the Indian space scientists in perfecting their indigenous cryogenic engine technology. India had long been deprived of the know-how, possessed exclusively by Russia and the US. The Missile Control Technology Regime(MCTR) forbids the either country to transfer the technology, though allows the sale of the engines.
India had to make do with second hand Russian engines till, after a series of failures, ISRO successfully test-fired 2.5 tonne class indigenous cryogenic engine in GSLV Mk-II on 5 January last year.

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