bluebird block-2 for 24 December 2025

The BlueBird Block-2 Mission marks a significant milestone in India’s space launch capabilities and global commercial space services. The mission involves the launch of a next-generation communication satellite of AST SpaceMobile, USA, using ISRO’s LVM3 (Gaganyaan-class heavy-lift rocket). Officially designated as LVM3-M6 / BlueBird Block-2, this mission represents the 6th operational flight of LVM3 and highlights India’s growing role in deploying advanced commercial satellites into Low Earth Orbit (LEO).

What is BlueBird Block-2?

BlueBird Block-2 is a next-generation space-based cellular broadband satellite developed by AST SpaceMobile. It is designed to deliver direct-to-mobile connectivity, enabling ordinary smartphones to connect to satellites without relying on terrestrial infrastructure.

Capabilities of BlueBird Block-2

• Provides 4G and 5G connectivity directly to standard smartphones
• Supports:
  • Voice calls
  • Video calls
  • Text messaging
  • Internet data services
• Operates without ground towers, dish antennas, or special handsets
• Offers global, continuous (24/7) coverage

Features of BlueBird Block-2 Satellite

• Heaviest Commercial Satellite to LEO: BlueBird Block‑2 weighs approximately 6,100 kg, making it the heaviest payload ever placed into Low Earth Orbit (LEO) by India’s LVM3 launch vehicle.
• Massive Phased‑Array Antenna: It carries a 223 m² phased‑array antenna, the largest commercial communications antenna deployed in LEO, enabling strong direct connectivity.
• Direct‑to‑Mobile Connectivity: The satellite is designed to provide 4G and 5G services directly to standard smartphones without special antennas or hardware.
• Global Coverage: It supports voice calls, video calls, messaging, streaming, and high‑speed data worldwide, including remote and underserved regions.
• Part of a LEO Constellation: BlueBird Block‑2 is part of AST SpaceMobile’s global Low Earth Orbit satellite network aimed at universal mobile broadband connectivity.

LVM3-M6 Mission

The LVM3-M6 mission is a dedicated commercial launch undertaken to place the BlueBird Block-2 communication satellite into Low Earth Orbit. The mission is executed through NewSpace India Limited (NSIL), ISRO’s commercial arm, underscoring India’s expanding footprint in the global space launch market.

• Mission Name: LVM3-M6 / BlueBird Block-2
• Launch Vehicle: LVM3 (GSLV Mk-III)
• Launch Site: Second Launch Pad, SDSC SHAR, Sriharikota
• Payload: BlueBird Block-2 Communication Satellite
• Client: AST SpaceMobile, USA
• Orbit: Low Earth Orbit (LEO)

This mission is notable for carrying the largest and heaviest commercial communication satellite ever deployed in LEO.

Why is this mission important?

• Direct-to-Mobile Connectivity: Enables ordinary smartphones to connect directly to the satellite without relying on ground towers or special devices, benefiting remote areas, oceans, and disaster-prone regions.
• Major Commercial Milestone: Executed through NewSpace India Limited, the mission demonstrates India’s capability to launch heavy commercial payloads, strengthening its position in the global space launch market.
• Part of Global LEO Constellation: Contributes to AST SpaceMobile’s worldwide Low Earth Orbit satellite network, enhancing global cellular broadband coverage.
• Technological Demonstration: Showcases India’s advanced launch vehicle technology (LVM3) and precision orbital insertion for extremely heavy payloads, reinforcing confidence in ISRO’s engineering expertise.
• Strategic and Societal Impact: Supports telecommunication expansion, disaster management, and connectivity in underserved regions, aligning with global digital inclusion initiatives.

LVM3 Three-Stage Configuration

The LVM3 (GSLV Mk-III) is a three-stage heavy-lift launch vehicle designed to place large satellites into Low Earth Orbit and Geosynchronous Transfer Orbit. Its configuration combines solid, liquid, and cryogenic propulsion, ensuring high thrust at lift-off and precise orbital insertion.

1. First Stage: S200 Solid Strap-On Boosters

• LVM3 uses two S200 solid rocket boosters attached on either side of the core stage.
• Each booster contains around 200 tonnes of solid propellant, making them among the largest solid boosters in operation globally.
• These boosters provide the maximum thrust during lift-off, accounting for nearly 80–85% of the total thrust at launch.
• Their primary role is to overcome Earth’s gravity and atmospheric drag in the initial phase of flight.
• The S200 boosters are developed by Vikram Sarabhai Space Centre (VSSC).
• After burnout, the boosters are jettisoned to reduce weight and improve flight efficiency.

2. Second Stage: L110 Liquid Core Stage

• The L110 is the central liquid-fuel stage of LVM3.
• It uses liquid propellants (UDMH and N₂O₄) and is powered by two Vikas engines.
• This stage provides controlled and sustained thrust after the solid boosters separate.
• The L110 stage ensures vehicle stability, trajectory correction, and velocity buildup during the mid-phase of the ascent.
• It bridges the transition from high-thrust lift-off to precise orbital insertion.
• After completing its burn, the L110 stage is also separated from the vehicle.

3. Third Stage: C25 Cryogenic Upper Stage

• The C25 stage is the most technologically advanced stage of LVM3.
• It is powered by an indigenously developed cryogenic engine (CE-20).
• The engine uses liquid hydrogen (LH₂) as fuel and liquid oxygen (LOX) as oxidiser.
• Cryogenic propulsion provides very high efficiency and specific impulse, crucial for placing heavy payloads into precise orbits.
• This stage performs the final orbital insertion, whether into LEO or Geosynchronous Transfer Orbit (GTO).
• The C25 stage has been designed and developed by ISRO’s Liquid Propulsion Systems Centre (LPSC).

Track Record of LVM3 Missions

• Proven National Mission Reliability: LVM3 has successfully launched Chandrayaan-2 and Chandrayaan-3, demonstrating its capability for complex scientific and lunar missions.
• Successful Commercial Deployments: It has completed two OneWeb missions, placing 72 satellites into Low Earth Orbit, establishing India as a trusted partner for large commercial satellite launches.
• Recent Operational Success: The LVM3-M5 / CMS-03 mission was successfully executed in November 2025, carrying a 4,400 kg communication satellite, showcasing the vehicle’s consistent reliability.

About Semi-Cryogenic Engine in India

• Indigenous Development: India is developing the SCE-200 semi-cryogenic engine indigenously at ISRO’s Liquid Propulsion Systems Centre (LPSC) to power future heavy-lift rockets.
• Fuel and Oxidizer: Uses kerosene (RP-1) as fuel and liquid oxygen (LOX) as oxidizer, offering higher efficiency than conventional liquid engines.
• High Payload Capability: Designed to enhance payload capacity to GTO and LEO, supporting heavier satellites and ambitious space missions.
• Cost-Effective Launches: The semi-cryogenic engine allows reduced launch costs due to better fuel efficiency and potential for partial reusability.
• Strategic Significance: Strengthens India’s indigenous heavy-lift launch capability, boosting commercial competitiveness and supporting national space exploration goals.