LVM3-M6 mission marks ISRO’s heaviest satellite launch into low Earth orbit

ISRO’s heaviest rocket, LVM3-M6, on Wednesday successfully placed the US-based BlueBird Block-2 communication satellite into low Earth orbit, marking a key milestone for India’s heavy-lift launch capability and its expanding role in the global commercial space market.

The 43.5-metre-tall LVM3 rocket lifted off at 8.54 am from the second launch pad at the Satish Dhawan Space Centre, Sriharikota, on a Christmas Eve mission. After a flight lasting about 15 minutes, the BlueBird Block-2 spacecraft separated from the launch vehicle and was successfully placed into its intended orbit.

ISRO said the satellite was injected into a 520 km circular low Earth orbit. The Bengaluru-headquartered space agency confirmed that the mission achieved all its objectives.

Weighing 6,100 kg, BlueBird Block-2 is the heaviest payload placed into low Earth orbit in the history of LVM3 launches from Indian soil. The previous heaviest satellite launched by the rocket was the LVM3-M5 Communication Satellite-03, weighing around 4,400 kg, which was placed into a geosynchronous transfer orbit on November 2.

The satellite was launched under a commercial agreement between NewSpace India Ltd (NSIL), the commercial arm of ISRO, and US-based AST SpaceMobile (AST & Science, LLC). The mission is part of AST SpaceMobile’s plan to build a global low Earth orbit constellation aimed at providing direct-to-mobile connectivity through satellite.

According to ISRO, the constellation is designed to enable 4G and 5G voice and video calls, text messaging, streaming and data services directly to smartphones, without the need for specialised satellite hardware.

AST SpaceMobile is building what it describes as the first space-based cellular broadband network that is accessible directly by smartphones and is intended for both commercial and government applications. The company said it launched five satellites — BlueBird 1 to BlueBird 5 — in September 2024, which currently provide continuous coverage across the United States and other select countries. It has partnered with over 50 mobile operators worldwide and plans further launches to augment its network.

The LVM3-M6 mission is the sixth operational flight of the LVM3 rocket and the third dedicated commercial mission to launch the BlueBird Block-2 spacecraft.

Also known as the Geosynchronous Satellite Launch Vehicle Mark III (GSLV-MkIII), the LVM3 is a three-stage heavy-lift rocket equipped with a cryogenic upper stage. The cryogenic engine was designed and developed by ISRO’s Liquid Propulsion Systems Centre, while the vehicle uses two S200 solid rocket boosters developed by the Vikram Sarabhai Space Centre, Thiruvananthapuram, to generate the thrust required for lift-off.

Prime Minister Narendra Modi congratulated ISRO for the successful mission, calling it a major step for India’s space programme and its commercial launch capabilities.

“A significant stride in India’s space sector. The successful LVM3-M6 launch, placing the heaviest satellite ever launched from Indian soil, the spacecraft of USA, BlueBird Block-2, into its intended orbit, marks a proud milestone in India’s space journey,” the prime minister said in a post on X.

“It strengthens India’s heavy-lift launch capability and reinforces our growing role in the global commercial launch market,” he said.

The prime minister said the mission also strengthened the foundation for future programmes such as Gaganyaan, India’s planned human spaceflight mission.

“With LVM3 demonstrating reliable heavy-lift performance, we are strengthening the foundations for future missions such as Gaganyaan, expanding commercial launch services and deepening global partnerships,” Modi said.

He also said the mission reflected the spirit of Aatmanirbhar Bharat and congratulated ISRO’s scientists and engineers for their work.

ISRO noted that the LVM3 rocket has completed eight consecutive successful launches, including high-profile missions such as Chandrayaan-2 and Chandrayaan-3.