Context:

• The Indian Space Research Organisation (ISRO) successfully launched the next-generation American communication satellite “BlueBird Block-2” on 24 December 2025 from Sriharikota, Andhra Pradesh, using its heaviest launch vehicle LVM3-M6.

Key Highlights

• Launch Vehicle: LVM3-M6 (also known as the “Bahubali” rocket)
• Payload: BlueBird Block-2 satellite
• Satellite Mass: Approximately 6,100 kg (6.1 tonnes)
• Manufacturer: AST SpaceMobile (USA)

Special Features of the Mission

• This is the heaviest commercial satellite ever launched by ISRO from Indian soil.
• The BlueBird Block-2 satellite can connect directly to ordinary 4G/5G smartphones without requiring special satellite phones or large antennas.
• It is equipped with a 223 square meter phased-array antenna, the largest commercial antenna ever deployed in Low Earth Orbit (LEO).
• The launch is part of a major commercial agreement between NewSpace India Limited (NSIL) and AST SpaceMobile (USA).
• NSIL is the commercial arm of ISRO.

LVM3 (Launch Vehicle Mark-3)

• ISRO’s most powerful and heavy-lift launch vehicle
• Earlier known as GSLV Mk-III
• Nicknamed “Bahubali” due to its heavy payload-carrying capability
• Type: Three-stage heavy-lift launch vehicle

Payload Capacity

• GTO (Geostationary Transfer Orbit): ~4,000 kg
• LEO (Low Earth Orbit): ~8,000 kg

Physical Specifications

• Height: 43.5 meters (equivalent to a 14-storey building)
• Lift-off Mass: ~640 tonnes

Three Stages of LVM3

1. S200 – Solid Boosters

• Two large strap-on boosters mounted on the sides
• Use solid fuel
• Provide massive thrust during lift-off

2. L110 – Liquid Core Stage

• Central stage with two Vikas engines
• Uses liquid propellants UH25 and N₂O₄

3. C25 – Cryogenic Upper Stage

• Most critical stage
• Powered by India’s largest CE-20 cryogenic engine
• Uses liquid hydrogen and liquid oxygen

Important Missions Using LVM3

• Chandrayaan-2 (2019): Proved LVM3’s capability to carry heavy lunar payloads
• OneWeb Missions (2022–23): Two successful launches of 36 satellites each on a commercial basis
• Chandrayaan-3 (14 July 2023): Enabled India’s historic soft landing near the Moon’s south pole
• Gaganyaan (Upcoming): India’s first human spaceflight mission; LVM3 is being human-rated

Low Earth Orbit (LEO)

• The orbit closest to Earth
• Used by most satellites, the International Space Station (ISS), and future space tourism missions

Altitude Range

• 160 km to 2,000 km above Earth

Orbital Characteristics

• Speed: ~27,400 km/h (7.6 km/s)
• Orbital Period: 90–120 minutes (multiple orbits per day)

Major Uses of LEO

• Satellite Communication: Starlink, OneWeb (low latency)
• Earth Observation: High-resolution imaging, weather monitoring, mapping
• Human Spaceflight: ISS, China’s Tiangong station, and India’s upcoming Gaganyaan mission

Other Major Earth Orbits

Medium Earth Orbit (MEO)

• Altitude: ~2,000 km to 35,786 km (commonly ~20,200 km)
• Use: Navigation satellites
• Examples: GPS (USA), GLONASS (Russia), Galileo (Europe)

Geosynchronous & Geostationary Orbits (GSO & GEO)

• Altitude: 35,786 km above Earth
• GSO: Orbital period equals Earth’s rotation (24 hours)
• GEO: A special GSO directly above the equator; satellites appear stationary
• Uses: TV broadcasting (DTH), satellite communication, weather forecasting
• Examples: India’s INSAT and GSAT satellites

Polar & Sun-Synchronous Orbits (SSO)

• Polar Orbit: Satellite passes over Earth’s poles, covering the entire planet over time
• Sun-Synchronous Orbit (SSO): A special polar orbit where the satellite passes over a location at the same local solar time
• Uses: Surveillance, weather monitoring, environmental studies
• Ideal for imaging due to consistent lighting conditions