Countdown for launch of ISRO’s Bluebird Block-2 Mission begins in Sriharikota

The 24-hour countdown for the launch of LVM3-M6 rocket, which will carry a new generation U.S. communication satellite commenced in Sriharikota on Tuesday (December 23, 2025), ISRO said.

In a dedicated commercial mission, ISRO is scheduled to launch the Bluebird Block-2 spacecraft on board its heavy lift launch vehicle LVM3-M6 at 8.54 a.m. from the second launch pad at this spaceport on Wednesday (December 24, 2025).

Weighing 6,100 kg, the communication satellite would be the heaviest payload to be placed into the Low Earth Orbit (LEO) in LVM3 launch history, the ISRO said.

The previous heaviest was the LVM3-M5 Communication Satellite 03, weighing about 4,400 kg that was successfully launched by ISRO on November 2.

Wednesday’s (December 24, 2025) mission is being undertaken as part of the commercial agreement signed between NewSpace India Ltd (NSIL) and US-based AST SpaceMobile (AST and Science, LLC). NewSpace India Ltd is the commercial arm of ISRO.

The historic mission would deploy the next generation communication satellite designed to provide high-speed cellular broadband directly to smartphones worldwide.

AST SpaceMobile is building the first and only space-based cellular broadband network, which is accessible directly by smartphones and designed for both commercial and government applications.

Ahead of the launch, ISRO Chairman V. Narayanan offered prayers at the Sri Venkateswara Swamy Temple in Tirumala on December 23.

According to the Indian space agency, the 43.5 metre tall LVM3, also known as Geosynchronous Satellite Launch Vehicle MkIII, is a three stage rocket with a cryogenic engine designed and developed by ISRO’s Liquid Propulsion Systems Centre.

The vehicle uses two S200 solid rocket boosters to provide the huge amount of thrust required for lift off. The booster has been developed by Vikram Sarabhai Space Centre.

After a flight of about 15 minutes from liftoff, the Bluebird Block-2 satellite is expected to get separated from the launch vehicle.

BlueBird Block-2 mission is part of a global LEO constellation to provide direct-to-mobile connectivity through satellite.

This constellation would enable 4G and 5G voice and video calls, texts, streaming and data for everyone, everywhere at all times. It features a 223m2 phased array, making it the largest commercial communications satellite every deployed into low Earth Orbit, about 600km altitude.

AST SpaceMobile had launched five satellites, BlueBird 1-5 in September 2024 which provide continuous internet coverage across the United States and other select countries.

The company has planned to launch similar satellites to augment its network support and has partnered with over 50 mobile operators across the globe.