The Indian Space Research Organization (ISRO) launched the GSAT-6A communication satellite today. It launched it with the help of the Geosynchronous Satellite Launch Vehicle (GSLV-F08) from Satish Dhawan Space Centre (SDSC) in Sriharikota.

This launch includes the 12th flight of Geosynchronous Satellite Launch Vehicle GSLV-F08 and sixth flight of the Cryogenic upper stage.



It is the high power S-band communication satellite with a lifespan of around 10 years. It is expected to blast off today at the Sriharikota rocket port at 4.56 pm from the second launch pad. According to ISRO GSAT-6A is similar to the GSAT-6. ISRO Chairman K Sivan said that GSAT-6A is followed by the launch of the navigation satellite.

The S-band in it will be in five spot beams and C-band in one beam. With the diameter of 6m, it also has a 0.8m fixed antenna used for hub communication link. The overall size of the GSAT-6A satellite is 1.53m X 1.65 m X 2.4 m.


S-band is an electromagnetic spectrum with frequencies ranging from 2 to 4 gigahertz (GHz). It crosses the boundary between the Ultra High Frequency (UHF) and Super High Frequency (SHF) bands at 3.0 GHz.  S-band is used by communications, weather radars and ship radar satellites. Its 2.5 GHz band is used across the globe for 4G services. The S-band spectrum is very much useful for mobile broadband services.

GSAT-6A provides a platform to develop technologies which demonstrate 6m S-Band Unfurlable Antenna. It includes handheld ground terminals and some network management techniques. It is very useful for satellite-based mobile communication applications.

Unfurlable Antenna

The Unfurlable Antenna is a six-meter-wide antenna with the shape of an umbrella. It will be rolled after the GSAT-6A satellite will get placed in orbit. It is specially designed for the purpose of a mission. This is three times broader than the current antennas used by ISRO. It will allow mobile communication across the globe with the help of hand-held ground terminals. Apart from communications, the GSAT-6A satellite is also design to be used for the military purpose as well.

After GSAT-6, it is India’s second main S-band communications satellite. GSAT-6 is orbiting around the Earth since August 2015 at 83 degrees East longitude. The GSAT-6A will be the last launch of ISRO’s for the financial year 2017-18. The cost of this heavily weighted 2-tonne satellite is approximately Rs.270 crores. It will require 17 minutes and 46.50 seconds to put the GSAT-6A satellite in its orbit from the launch pad in Sriharikota to its blast off.

Stages of GSAT-6A

The GSAT-6A launch will include three stages

Stage one is the payload fairing which will comprise of two propellants – Earth storable liquid propellants and Composite solid propellant. Stage Two will include Earth storable liquid propellants, while State Three comprises of Cryogenic propellants.


GSLV-F08 weighs 415.6 tonnes with a height of 49.1 meter. It included multiple improvements like induction of High Thrust Vikas Engine, replacement of electromechanical actuation system in place of the electro-hydraulic actuation system.

GSLV-F08 targeted Geosynchronous Transfer Orbit or GTO includes ‘perigee’ of 170 kilometers, and ‘apogee‘ of 35,975 kilometers with an ‘inclination‘ of 20.63 degrees, and an ‘azimuth‘ of 108 degrees. The mission includes a movement using the satellite’s onboard propulsion system with the help of three orbits. GSAT-6A targeted orbit is focused at 36,000 kilometers. It will include a geostationary orbit at an inclination of zero degrees once in place over the 83 degrees east longitude.

The largest launch vehicle developed by India is Geosynchronous Satellite Launch Vehicle Mark II (GSLV Mk II) which is currently in operation. It is the fourth generation launch vehicle having three stages with four liquid strap-ons. The third stage of GSLV Mk II is formed by the Cryogenic Upper Stage (CUS). The vehicle has achieved four consecutive successes since January 2014.


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