ISRO’s Bluebird Block-2 launch countdown begins at Sriharikota
At 6,100 kg, the communication satellite becomes LVM3’s heaviest-ever payload launched into Low Earth Orbit, ISRO said
The countdown has begun at Sriharikota for a landmark commercial space mission, as the Indian Space Research Organisation (ISRO) prepares to launch its heavy-lift LVM3-M6 rocket carrying a next-generation U.S. communication satellite into orbit.
ISRO said the 24-hour countdown for the launch commenced on Tuesday, December 23, 2025, at the Satish Dhawan Space Centre. The rocket is scheduled to lift off at 8.54 a.m. on Wednesday, December 24, from the second launch pad, marking another major milestone for India’s growing role in the global commercial space market.
The mission will place the Bluebird Block-2 spacecraft into Low Earth Orbit (LEO) as part of a dedicated commercial launch. Weighing 6,100 kg, the satellite will be the heaviest payload ever carried into LEO by the LVM3 rocket in its launch history, underlining the increasing capabilities of India’s most powerful launch vehicle.
ISRO officials noted that the previous heaviest payload launched by the LVM3 was the Communication Satellite-03 on the LVM3-M5 mission, which weighed around 4,400 kg and was successfully launched on November 2. The significant jump in payload mass highlights both the maturity of the LVM3 system and the confidence international clients are placing in ISRO’s launch services.
Wednesday’s mission is being carried out under a commercial agreement between NewSpace India Limited (NSIL), ISRO’s commercial arm, and U.S.-based AST SpaceMobile, also known as AST and Science, LLC. The collaboration reflects India’s expanding footprint in providing reliable and cost-effective launch solutions for global satellite operators.
The Bluebird Block-2 satellite represents a new generation of communication spacecraft designed to deliver high-speed cellular broadband connectivity directly to smartphones across the world. Unlike traditional satellite communication systems that rely on specialised terminals or ground equipment, this technology aims to connect ordinary mobile phones directly to satellites in space, potentially transforming access to communication in remote and underserved regions.
AST SpaceMobile is working to build what it describes as the world’s first and only space-based cellular broadband network that is accessible directly by smartphones. The network is intended to support both commercial and government applications, including emergency response, disaster relief, and connectivity in areas beyond the reach of conventional mobile towers.
Ahead of the launch, ISRO Chairman V. Narayanan visited the Sri Venkateswara Swamy Temple in Tirumala on December 23, where he offered prayers for the success of the mission. Such visits have become a familiar ritual before major launches, reflecting the blend of cutting-edge science and deeply rooted cultural traditions that often accompanies India’s space endeavours.
The LVM3, also known as the Geosynchronous Satellite Launch Vehicle Mark III, stands 43.5 metres tall and is ISRO’s most powerful rocket. It is a three-stage launch vehicle equipped with a cryogenic upper stage, designed and developed by ISRO’s Liquid Propulsion Systems Centre. The rocket has been steadily proving its reliability through a series of successful missions, including crew module tests for India’s human spaceflight programme and high-value commercial launches.
After liftoff, the LVM3-M6 will take approximately 15 minutes to place the Bluebird Block-2 satellite into its intended orbit. ISRO said the spacecraft is expected to separate smoothly from the launch vehicle at the end of this phase, marking the successful completion of the launch segment of the mission.
For ISRO and NSIL, the mission is more than just another launch. It signals India’s rising stature as a trusted partner in the global space economy and demonstrates the ability of its launch systems to handle complex, heavy payloads for international customers. As the countdown ticks away at Sriharikota, the mission carries not only a powerful satellite into space, but also the ambitions of a space programme increasingly shaping the future of global connectivity.