ISRO Launches Heaviest Defence Communication Satellite for Indian Navy

Context:

• In November 2025, the Indian Space Research Organisation (ISRO successfully launched India’s heaviest military communication satellite CMS-03 (GSAT-7R)

• The satellite, weighing 4,410 kg, was launched aboard the indigenously developed LVM3-M5 rocket (formerly GSLV Mk-III) from the Second Launch Pad at Satish Dhawan Space Centre (SDSC), Sriharikota, Andhra Pradesh.

• The mission strengthens India’s military communication capabilities, particularly for maritime security across the Indian Ocean Region.

Key Highlights:

• Mission / Launch Details:

  • What: Launch of India’s heaviest military communication satellite

  • Satellite: CMS-03 / GSAT-7R

  • Weight: 4,410 kg

  • Launch Vehicle: LVM3-M5 (formerly GSLV Mk-III; also called “Bahubali”)

  • Launch Site: SDSC, Sriharikota (Andhra Pradesh)

  • Orbit Inserted: Geosynchronous Transfer Orbit (GTO)

  • Designed for: Indian Navy

  • Coverage: Entire Indian Ocean Region (IOR)

• Significance of Mission:

  • 5th operational flight of the LVM3 launcher.

  • First time India launched a heavy satellite (above 4,000 kg) using an indigenous launch vehicle from Indian soil.

  • Demonstrates growing self-reliance in strategic space infrastructure.

• Comparison with Earlier Heavy Satellite Launches:

  • Earlier heavy satellites were launched via foreign launch vehicles:

    • GSAT-11 (5,854 kg) – Ariane

    • GSAT-24 (4,181 kg) – Ariane

    • GSAT-20 (4,700 kg) – SpaceX

• About CMS-03 / GSAT-7R:

  • Multi-band military communication satellite for naval operations.

  • Equipped with advanced payloads in:

    • UHF

    • S-band

    • C-band

    • Ku-band

  • Indigenous technologies include:

    • 1,200-litre propulsion tank

    • Collapsible antenna systems

  • Designed operational life: 15 years.

  • Replaces GSAT-7 (Rukmini) launched in 2013 (Ariane-5).

• Earlier Related Defence Satellite:

  • GSAT-7A – communication satellite designed for the Indian Air Force (IAF).

• About LVM3 Rocket:

  • ISRO’s most powerful rocket.

  • Payload capability:

    • 8,000 kg to Low Earth Orbit (LEO)

    • 4,000 kg to Geosynchronous Orbit (GEO/GTO insertion)

  • Specifications:

    • Height: 43.5 m

    • Diameter: 4.0 m

    • Lift-off mass: 640 tonnes

    • Payload fairing diameter: 5.0 m

  • 3-stage configuration:

    • Solid strap-ons: S200

    • Liquid core stage: L110

    • Cryogenic stage: C25 / upgraded stage

• Upgradation in LVM3-M5:

  • Payload capability increased by 10% compared to LVM3-M4 (Chandrayaan-3).

  • Cryogenic stage upgraded from:

    • C25 (28,000 kg fuel, 20-tonne thrust)

    • to C32 (32,000 kg fuel, 22-tonne thrust)

Relevant Prelims Points:

• Issue & Background:

  • Secure satellite-based communication is critical for modern warfare and maritime surveillance.

  • Indian Navy requires uninterrupted communication for fleet coordination across vast oceanic regions.

• Key Terms:

  • GTO (Geosynchronous Transfer Orbit): An elliptical orbit used as a transfer path before reaching geostationary orbit.

  • Military Communication Satellite: Enables encrypted, secure communication for armed forces.

• GSAT-7 Series:

  • GSAT-7 (Rukmini): Naval communication satellite launched in 2013.

  • GSAT-7A: For Indian Air Force communication.

  • GSAT-7R / CMS-03: New-generation satellite for Navy.

• Benefits / Importance:

  • Strengthens India’s maritime security and strategic reach in the IOR.

  • Enhances coordination for naval operations and disaster response.

  • Improves surveillance and command-and-control integration.

• Challenges / Risks:

  • Space assets vulnerable to cyber threats and anti-satellite weapon systems.

  • Need for redundancy and multi-satellite networks.

  • High cost of launch and satellite development.

• Impact (India + Global):

  • Reinforces India’s role as a major space power.

  • Enhances strategic deterrence in the Indo-Pacific.

  • Supports India’s growing defence space ecosystem.

Relevant Mains Points:

• Core Concept / Static Linkage:

  • Role of satellites in national security and defence preparedness.

  • Strategic importance of the Indian Ocean Region (IOR) for trade routes and geopolitical stability.

  • Defence technology as a component of self-reliance (Atmanirbharta).

• Governance / Institutional Framework:

  • ISRO’s role in strategic space missions.

  • Defence Space Agency (DSA) and integration of military space requirements.

  • Strengthening civil-military cooperation in space technology.

• Security / Technological Dimensions:

  • Military satellites enhance:

    • Network-centric warfare

    • Secure command and control

    • Intelligence, surveillance, and reconnaissance (ISR)

  • Indigenisation reduces dependency on foreign launch systems.

• Keywords for Answer Writing:

  • Strategic Autonomy

  • Defence Communication Satellite

  • Space Security

  • Network-Centric Warfare

  • Indian Ocean Region

  • Atmanirbhar Bharat

• Way Forward:

  • Develop a constellation of defence communication satellites.

  • Strengthen cyber resilience and anti-jamming technologies.

  • Promote indigenous private sector participation in launch services.

  • Enhance space situational awareness and satellite protection mechanisms.

  • Integrate defence satellites with maritime surveillance systems.

UPSC Relevance (GS-wise):

• GS2: Internal security, strategic infrastructure, defence preparedness.

• GS3: Science & Technology, space technology, defence manufacturing.

• GS4: Ethical use of space for national security and peaceful purposes.