BlueBird Block-2: ISRO Launches Heaviest Satellite Using LVM-3

Why in News?

ISRO has achieved a major milestone by successfully launching BlueBird Block-2, the heaviest satellite ever placed in orbit by India, weighing 6,100 kg, using the Launch Vehicle Mark-3 (LVM-3). The satellite belongs to the US-based firm AST SpaceMobile, and the mission highlights India’s growing strength in heavy-lift commercial launches.

What is BlueBird Block-2?

About BlueBird Block-2 Rocket

BlueBird Block-2 is a next-generation commercial communications satellite developed by AST SpaceMobile.
It surpassed ISRO’s previous payload record of ~5,700 kg (OneWeb satellites).
The satellite was placed in Low Earth Orbit at ~520 km altitude.

Objectives of the Launch

To provide direct-to-mobile connectivity, enabling 4G and 5G services directly on standard smartphones without specialised ground stations or terminals.
This has major implications for remote connectivity, disaster response, and digital inclusion.

Commercial Significance of the Mission

This is ISRO’s third commercial mission using LVM-3, after two successful OneWeb launches in 2022 and 2023.
Despite competition from SpaceX’s Falcon-9 and Europe’s Ariane-6, LVM-3 offers cost-effective heavy-lift capability, strengthening India’s position in the global launch market.

Low Earth Orbit (LEO)

Overview of LEO

Altitude range: ~160 km to 2,000 km above Earth.
Orbital period: ~90–120 minutes per revolution.

Importance of LEO

LEO is ideal for:
- Communication satellites (low latency)
- Earth observation and remote sensing
- Scientific and technology demonstration missions

Special Orbits

While most LEO satellites use circular orbits, some operate in elliptical orbits:
- Molniya and Tundra orbits provide extended coverage over high-latitude regions where geostationary satellites are less effective.

What is the LVM-3 Launch Vehicle?

About the LVM-3 Launch Vehicle

LVM-3 (earlier GSLV Mk-III) is ISRO’s most powerful heavy-lift rocket.
Payload capacity:
- ~4,000 kg to GTO
- ~8,000 kg to LEO
First successful launch: December 2014

Three-Stage Configuration

First Stage (S200 Boosters)
- Two large solid rocket boosters
- Propellant: HTPB (Hydroxyl-Terminated Polybutadiene)
Second Stage (L110 Core Stage)
- Liquid-fuelled stage
- Engines: Two Vikas engines
- Propellants: UDMH + Nitrogen Tetroxide
Third Stage (C25 Cryogenic Stage)
- Engine: CE-20
- Propellants: Liquid Hydrogen + Liquid Oxygen

Engine Optimisation and Future Upgrades

Cryogenic Stage Upgrade

Development of C32 cryogenic stage with higher thrust and fuel capacity.

Semi-Cryogenic Engines

Uses kerosene + liquid oxygen.
Expected to increase LEO payload capacity from 8,000 kg to ~10,000 kg.

Bootstrap Reignition Technology

Enables restart of cryogenic engines without external gases (like helium).
Reduces fuel mass and improves efficiency for multi-orbit missions.

Role in India’s Future Space Missions

A human-rated LVM-3 will serve as the launch vehicle for:
- Gaganyaan human spaceflight missions
- Modules of the Bharatiya Antariksh Station, India’s proposed space station

Conclusion

The successful launch of BlueBird Block-2 marks a turning point for ISRO’s commercial heavy-lift capability. With continuous upgrades to LVM-3, India is positioning itself not just as a reliable launch service provider, but as a strategic player in next-generation global connectivity and human spaceflight missions.

Summary

BlueBird Block-2 (6,100 kg) is the heaviest payload launched by ISRO, injected into Low Earth Orbit (LEO).
The satellite will enable direct-to-mobile 4G/5G connectivity without ground-based towers.
The mission showcases upgrades and future potential of LVM-3, including cryogenic stage enhancements, semi-cryogenic engines, and bootstrap reignition technology.