Within the next 15 minutes, the Bluebird Block-2 satellite is expected to separate from the launch vehicle.
The launch is also significant for ISRO as the Bluebird Block-2, weighing 6,100 kg, is the heaviest payload ever placed into Low Earth Orbit (LEO) by the space agency's LVM3 rocket.
The mission is being carried out as part of a commercial agreement between ISRO's commercial arm NewSpace India Ltd (NSIL) and US-based AST SpaceMobile, also known as AST and Science LLC.
At 6,100 kg, this is the heaviest payload to be placed by ISRO's heavy-lift launch vehicle LVM3. The previous record was held by the LVM3-M5 Communication Satellite-03, which weighed around 4,400 kg and was successfully launched by ISRO on November 2 into the Geosynchronous Transfer Orbit (GTO).
It is also notable that the mission aims to provide high-speed cellular broadband directly to smartphones worldwide by placing a next-generation communication satellite in orbit.
US-based AST SpaceMobile is developing the first space-based cellular broadband network that connects directly to regular smartphones. The network is intended for both commercial and government use and will support 4G and 5G voice and video calls, messaging, streaming and data services across the globe.
The 43.5-metre-tall LVM3, also known as the Geosynchronous Satellite Launch Vehicle (GSLV) Mk III, is a three-stage rocket. It uses a cryogenic engine designed and developed by ISRO's Liquid Propulsion Systems Centre, according to the space agency.
The vehicle is fitted with two S200 solid rocket boosters that provide the high thrust needed for lift-off. These boosters were developed by the Vikram Sarabhai Space Centre in Thiruvananthapuram.
In previous missions, the LVM3 has successfully launched Chandrayaan-2, Chandrayaan-3 and two OneWeb missions that together carried 72 satellites.