The 29-hour countdown for the launch of GSat-6 communication satellite using GSLV rocket will start on August 26 at 11.52 am while the official launch will take place tomorrow.

According to Indian Space Research Organisation, “Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) have cleared the starting of the 29-hr countdown at 1152 hrs”.

“The countdown of GSLV-D6/GSAT-6 Mission has commenced today (Wednesday)”. About 17-18 minutes after lift off, the satellite will be placed into the geosynchronous transfer orbit.

The 2,117 kg Indian-made satellite carries a very special giant antennae which will open up in space like an umbrella. It will provide S-band communication services in the country. It is hoped that together, they will cover the entire country. This is the largest satellite antenna realised by ISRO.

One of the advanced features of GSAT-6 satellite is its S-Band Unfurlable Antenna of six metre diameter. This antenna is utilised for five spot beams over India.

GSAT-6 seen with two halves of payload faring of the GSLV-D6. This is the third time the indigenously developed cryogenic upper stage (CUS) is being carried on-board during a GSLV flight.

Over the last three decades, there were generations of top class engineers who worked on the stage, even as the ISRO successfully sent the Polar Launch Vehicles one after the other. The overall length of GSLV-D6 is 161 ft (49 meters). with a lift-off mass of 416 tons. Nineteen months after it successfully flight-tested India’s first home-made cryogenic engine, Isro is ready for a keenly-awaited encore.

The cryogenic stage is an extremely complex system that only a few among the elite group of countries that have space capabilities possess.

A cryogenic engine is more efficient as it provides more thrust for every kilogram of propellant burnt. During the flight, the CUS fires for a nominal duration of approximately 720 seconds. In 2013, India had launched a dedicated communications satellite for the Indian Navy. Previous GSLV vehicles (GSLV Mk I) have used Russian cryogenic engines.

S-band telemetry and C-band transponders enable GSLV-D6 performance monitoring, tracking, range safety/flight safety and Preliminary Orbit Determination (POD).