Isro puts GSAT-6 in orbit

Scientists get cryogenic engine right, vital for future launches
Last Updated 27 August 2015, 20:11 IST

Scripting another new chapter in its space technology, India on Thursday moved a step forward by successfully launching communication satellite GSAT-6 using its heavy rocket geosynchronous satellite launch vehicle (GSLV-D6).

The 49.1 metre-tall rocket weighing 416 tonnes took off precisely at 4:52 pm from the second launch pad at the Satish Dhawan Space Centre (SDSC), in this island in the Bay of Bengal, about 90 km north of Chennai.

This mission assumes more significance as this successful flight of GSLV rocket will give the Indian space programme the much needed booster by getting the cryogenic engine right, which is vital for its future launches.

Indian Space Research Organisation (Isro) scientists, including its Chairman A S Kiran Kumar at the mission control centre, were jubilant and hugged each other when the rocket successfully placed the satellite into the Geosynchronous Transfer Orbit after about 17 minutes of its launch.

“As a result of tremendous amount of hard work by our team, today’s performance of the launch vehicle clearly demonstrates that all the systems were performing very normally,” Kiran Kumar said.

“The intricacies of cryogenic engine have been understood,” he added. 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.
Recently, the Isro had successfully ground tested the indigenously developed High Thrust Cryogenic Rocket Engine for a duration for 800 seconds on July 20 at the Liquid Propulsions Centre at Mahendragiri in Tamil Nadu.

This is the third time the indigenously developed Cryogenic Upper Stage (CUS) was being carried on board a GSLV flight. The GSLV is a three stage engine rocket has a total carrying capacity of around 2.2 tonne. The first stage is fired with solid fuel, the second with liquid fuel and the third is the cryogenic engine.

The satellite provides communication through five-spot beams in S-band and a national beam in C-band for strategic users.

The cuboid shaped GSAT-6 has a lift-off mass of 2,117 kg. Of this, propellants weigh 1,132 kg and the dry mass of the satellite is 985 kg.

One of the advanced features of GSAT-6 satellite is its S-Band Unfurlable Antenna of six-metre diameter. This is the largest satellite antenna realised by Isro. This antenna is utilised for five spot beams over the Indian main land. The spot beams exploit the frequency reuse scheme to increase frequency spectrum utilisation efficiency.

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 Geostationary Orbit.

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 degree East longitude.The satellite’s life span is nine years. 

(Published 27 August 2015, 20:11 IST)

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