CHENNAI: The 29-hour countdown for tomorrow’s launch of advanced communication satellite GSAT-6 using the GSLV-D6 rocket, powered by the indigenous cryogenic engine, began at 1152 hrs today at the spaceport of Sriharikota, about 100 km from here.
Indian Space Research Organisation (ISRO) sources told that the GSLV-D6, carrying the 2117 kg satellite, would lift from the Second Launch Pad at 1652 hrs tomorrow evening.
The Mission Readiness Review (MRR) Committee and the Launch Authorisation Board (LAB) have cleared the launch, following which the 29-hour countdown commenced this noon. During the countdown, propellant filling operations would be carried out in the three-stage vehicle.
About 17-18 minutes after lift off, the Satellite would be placed into the Geosynchronous Transfer Orbit (GTO) with a perigee of 170 km from the earth and an apogee of 35,975 km, with an inclination of 19.95 deg.
This would be the first GSLV mission for ISRO in 19 months, the last one being the successful GSLV-D5 mission in January last year.
The launch comes in the backdrop of ISRO successfully ground testing the indigenously developed High Thrust Cryogenic Rocket Engine for a full duration for 800 seconds on July 20 at the Liquid Propulsions Centre at Mahendragiri in Tamil Nadu.
The sources said GSLV-D6 would be the ninth flight of India’s Geosynchronous Satellite Launch Vehicle (GSLV). It is also the fifth developmental flight of GSLV.
This is the third time the indigenously developed Cryogenic Upper Stage (CUS) was being carried on-board a GSLV flight. The 49.1 m tall GSLV-D6, with a lift-off mass of 416 tonnes, was significant since it intends to continue the testing of CUS. GSLV is designed to inject 2-ton class of communication satellites into the GTO.
GSAT-6 will provide S-band communication services in the country.
S-band telemetry and C-band transponders enable GSLV-D6 performance monitoring, tracking, range safety/flight safety and Preliminary Orbit Determination (POD).
After reaching GTO, GSAT-6 will use its own propulsion system to reach its final geostationary orbital home and would be stationed at 83 Deg East longitude.
The sources said GSLV-D6 vehicle was configured with all its three stages, including the CUS similar to the ones successfully flown during the previous GSLV-D5 mission in January 2014, when GSLV-D5 successfully placed GSAT-14 satellite in the intended GTO very accurately. The sources said GSAT-6 is the 25th geostationary communication Satellite of India built by ISRO and 12th in the GSAT series.
Five of GSAT-6’s predecessors were launched by GSLV during 2001, 2003, 2004, and 2007 and 2014 respectively. After its commissioning, GSAT-6 will now join the group of India’s other operational geostationary satellites.
GSAT-6 satellite will provide communications through five spot beams in S-band and a national beam in C-band for strategic uses.
The advanced feature of the cuboid shaped GSAT-6 will be its S-Band unfurlable Antenna of 6 m diameter. This is the largest satellite antenna realised by ISRO and it would be utilised for five spot beams over the Indian main land.
The spot beams exploit the frequency reuse scheme to increase frequency spectrum utilisation efficiency. The other advanced feature of the satellite will be the 70 v bus, which is flying first time in an Indian communication satellite.
After its injection into the GTO, ISRO’s Master Control Facility (MCF) at Hassan takes control of GSAT-6 and performs the initial orbit raising manoeuvres by repeatedly firing the Liquid Apogee Motor (LAM) on-board the satellite, finally placing it in the circular GTO.
After this, deployment of the antenna and three axis stabilisation of the satellite will be performed and the GSAT-6 will be positioned at 83 deg East longitude. (AGENCIES)
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