The twenty-five-and-a-half-hour countdown to place the country’s heaviest satellite into orbit started at 3.58 p.m. on Sunday. ISRO will be aiming to put into orbit the communication satellite, GSAT-19, on board the GSLV-MkIII-D1.
The GSLV-D1 will be powered by an indigenous cryogenic engine. While indigenous cryogenic engines have been carried on earlier flights as well in recent years, they were modelled on cryogenic engines designed by Russia. “This cryogenic engine is out- and-out indigenous. That makes it unique,” an ISRO official told The Hindu.
Developmental flight
This will also be the first developmental flight of the GSLV-MkIII, which is capable of carrying heavy payloads. The vehicle can put payloads of up to 4,000 kg in a Geosynchronous Transfer Orbit (GTO), and up to 10,000 kg in to Low Earth Orbit (LEO). The launch has been scheduled at 5.28 p.m. from the Satish Dhawan Space Centre, Sriharikota.
The GSLV-MkIII is a three-stage vehicle designed to carry heavier communication satellites into GTO. The vehicle has two strap-on motors that will fire at launch and will separate at 140 seconds after take-off. The liquid stage on the main rocket will ignite during the strap-on motors “thrusting phase” and will keep firing after the strap-on motors separate. The core-stage (liquid stage) separation will happen at 5 minutes and 20 seconds after lift-off and the cryo-stage ignition happens two seconds later.