The Indian Space Research Organisation, widely known as ISRO, achieved a major milestone on Wednesday, 24th December, by successfully launching the LVM3-M6 mission.

This mission carried the United States’ next-generation BlueBird Block-2 communications satellite into Low Earth Orbit, also known as LEO. With a massive weight of 6,100 kilograms, this satellite has become the heaviest foreign satellite ever launched by India’s LVM3 rocket into LEO. This achievement sets a fresh record for India’s heavy-lift launch vehicle and highlights the growing global trust in ISRO’s launch capabilities.

The launch was conducted smoothly from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh. ISRO confirmed that every phase of the mission was executed as planned, marking yet another flawless operation for the space agency. The LVM3 launch vehicle, also called GSLV Mk III, stands 43.5 metres tall and is currently the strongest rocket developed by India. It is designed to handle heavy payloads and complex missions, making it a key asset in India’s space programme.

The GSLV Mk III uses a three-stage configuration and features a cryogenic upper stage, a technology developed by ISRO’s Liquid Propulsion Systems Centre. This advanced stage plays a critical role in placing heavy satellites accurately into their intended orbits. For lift-off, the rocket relied on two powerful S200 solid strap-on boosters, which generated the enormous thrust required to carry the 6,100 kg satellite off the launch pad. These boosters were developed by the Vikram Sarabhai Space Centre in Thiruvananthapuram and are among the most powerful solid rocket boosters in use today.

This mission was carried out under a commercial agreement between NewSpace India Limited, or NSIL, which is ISRO’s commercial arm, and the US-based company AST SpaceMobile. The BlueBird Block-2 satellite is a key component of AST SpaceMobile’s ambitious plan to build a space-based cellular broadband network. The goal of this network is to allow regular smartphones to connect directly to satellites without the need for any special hardware or modifications, potentially changing the way mobile connectivity works across the world.

Purpose and goals of the BlueBird Block-2 satellite

According to ISRO, the BlueBird Block-2 satellite is designed to deliver high-speed mobile connectivity on a global scale. It is capable of supporting both 4G and 5G networks, along with a wide range of communication services. These include voice calls, video calls, messaging, data transfer, and media streaming, making it suitable for everyday mobile use even in remote or underserved regions.

The satellite is part of a larger constellation of satellites being developed by AST SpaceMobile in Low Earth Orbit. Together, these satellites are intended to create continuous mobile coverage across vast areas of the planet. One of the most striking features of the BlueBird Block-2 satellite is its enormous phased array antenna, which covers an area of 223 square metres. This makes it the largest communications satellite operating in LEO, at an orbital height of approximately 600 kilometres above the Earth.

AST SpaceMobile has already made significant progress with its project. In September 2024, the company launched five similar satellites, named BlueBird 1 through BlueBird 5. These satellites are currently providing continuous mobile internet coverage across the United States and selected other regions. Looking ahead, the company plans to expand its network further and has already partnered with more than 50 mobile operators around the world, signalling strong industry support for its space-based connectivity vision.

November mission that previously held ISRO’s heavy-launch record

Before the LVM3-M6 mission, ISRO’s record for launching its heaviest satellite was set earlier this year, in November. On 2nd November, ISRO successfully launched the Indian Navy’s GSAT-7R, also known as CMS-03, using the LVM3 rocket. The satellite weighed around 4,400 kilograms, making it India’s heaviest communication satellite launched from Indian soil at the time. It was placed into Geosynchronous Transfer Orbit, or GTO, during that mission.

GSAT-7R is a fully indigenous satellite developed to meet the strategic communication requirements of the Indian Navy. Built using advanced homegrown technology, the satellite is expected to significantly strengthen the Navy’s maritime communication and surveillance capabilities across the Indian Ocean Region. Its design reflects India’s growing expertise in developing complex and secure space systems.

The satellite is intended to provide secure and high-bandwidth connectivity between naval ships, submarines, aircraft, and shore-based command centres. In addition to enhancing operational coordination, GSAT-7R will also replace the older GSAT-7, also known as Rukmini, which was launched in 2013. This replacement marks an important step in India’s continued push towards self-reliance in both defence and space technologies, while steadily upgrading its strategic infrastructure.