CHENNAI: The Indian Space Research Organisation (ISRO) on Thursday successfully placed 2-tonne communication satellite GSAT-6A in the designated orbit, which also fulfils some of the strategic needs of armed forces besides boosting mobile communication across the country. In a perfect lift-off at 4.56 pm from the second launch pad in Sriharikota, GSLV-F08 roared into the clear skies and in next 17 minutes 41 seconds accomplished the mission.
The GSAT-6A will complement GSAT-6, which has been orbiting since August 2015. 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-6A has a lift-off mass of 2,140 kg, of which propellants weigh about 1,200 kg and the dry mass of the satellite is around 940 kg.
One of the advanced features of the GSAT-6A satellite is its S-Band Unfurlable Antenna of 6-m diameter. This is one of the largest satellite antennas realised by ISRO. This antenna is utilised for five spot beams over the Indian main land. After its injection into GTO by GSLV-F08, ISRO’s master control facility at Hassan takes control of of GSAT-6A and performs the initial orbit raising manoeuvres by repeatedly firing the Liquid Apogree Motor (LAM) on-board the satellite, finally placing it in the geostationary orbit. After this, deployment of the antenna and stabilisation of the satellite will be performed. GSAT-6A will be positioned at 83 degrees east longitude in about a week, ISRO scientists said.
Speaking after the first successful launch under his stewardship, ISRO chairman K Sivan said the GSAT-6A along with GSAT-6 will provide a platform for development of advanced technologies for point-to-point satellite communication. He said the GSLV rocket had major improvements to enhance its payload carrying capability by 50% upto 3 tonnes. The induction of high-thrust Vikas engine in the second stage of the vehicle has boosted the thrust by six per cent. Besides, the rocket has been fitted with electromechanical actuation system in the place of electro-hydraulic actuation system and is guided by indigenously developed space grade lithium-ion (Li-Ion) cells. “The lithium-ion batteries are being looked up by the Government of India in its endeavour to popularise e-vehicles,” he said.
V Somanath, director, Vikram Sarabhai Space Centre (VSSC), said the ‘naughty boy’ GSLV, which tasted five failures in the past causing jitters among ISRO ranks, has now emerged as a reliable vehicle. “This successful launch has proved that GSLV has matured as a reliable launch vehicle to launch Chandrayaan-2 mission.”
10 launches in next 9 months
Sivan said the next nine months would be action-packed with 10 launches lined up covering a wide spectrum of areas such as remote sensing, communication, navigation and inter-planetary mission.
Shar director P Kunhikrishnan said launch campaign for two more immediate missions has already begun. PSLV-C41 carrying navigation satellite IRNSS-1I, which is realised by the industry, has been fully integrated at the first launch pad and due for launch in two weeks. GSLV MkIII-D2, which is the second development flight of GSLV MkIII, carrying GSAT-29 configured around ISRO’s enhanced I-3K is also gearing up for launch. It carries Ka x Ku multi-beam and optical communication payloads for the first time. The mission targets Village Resource Centres (VRC) in rural areas to bridge the digital divide.
Next gen Vikas engine shines
Liquid Propulsion Systems Centre (LPSC) director V Narayanan said the high-thrust Vikas engine flown for the first time has been successfully demonstrated. The thrust of the second stage has been enhanced from 80 tonnes to 85 tonnes. The last depletion mode shutdown, which used the cryogenic propellants to optimum well, also went well. This has set the ball rolling for future missions. The next-generation Vikas engine will be used for Chandrayaan-2 mission to gain an additional payload capacity of 240 kg.
Launch sequence
Few seconds before the launch countdown reached zero, the four liquid propellant strap-on motors of GSLV-F08, each with nearly 43 tonnes of liquid propellants, were ignited
At count zero and after confirming the normal performance of all the four strap-on motors, the 139 tonne solid propellant first stage core motor was ignited and GSLV lifted off at 4.56 pm, as scheduled
The major phases of the flight occurred as intended. About 17 minutes and 41 seconds after lift-off, GSAT-6A was successfully placed in GTO
Soon after separation from GSLV, the two solar arrays of GSAT-6A were automatically deployed in quick succession and the Master Control Facility (MCF) at Hassan in Karnataka assumed control of the satellite
GSAT-6A is a communication satellite built by ISRO to provide mobile communication services through multi beam coverage. For this, it is equipped with S and C band transponders
Satellite cost: Rs 270 crore
Current position
In its oval shaped GTO, GSAT-6A is now orbiting the Earth with a perigee (nearest point to Earth) of 169.4 km and an apogee (farthest point to Earth) of 36,692.5 km