ISRO Achieves 175‑Tonne Semi‑Cryogenic Engine Hot Test, Paving Path to 200‑Tonne Thrust for LVM3 Upgrade

ISRO has achieved a major milestone by successfully conducting a hot test of its Semi‑Cryogenic Engine Power Head Test Article (PHTA) at 175‑tonne thrust on June 24, 2026, at the ISRO Propulsion Complex, Mahendragiri, Tamil Nadu. This test marks a crucial step toward full‑scale 200‑tonne thrust capability, strengthening India’s indigenous launch vehicle technology.

Notably, the Semi‑cryogenic engines use liquid oxygen (LOX) and isrosene (purified kerosene), which are cleaner and more efficient than older toxic fuels.

A full‑scale 200‑tonne thrust rocket engine means the engine can push with a force equal to lifting about 200 tonnes (200,000 kilograms) straight off the ground — imagine the weight of 130 cars being lifted at once. It’s the raw “push power” that propels a massive rocket skyward.

A 200‑tonne thrust class engine puts ISRO in the league of agencies like NASA and Roscosmos, which use similar high‑power engines for heavy‑lift missions.

ISRO Achieves 175‑Tonne Semi‑Cryogenic Engine Hot Test

Key Highlights of the Test

• Date & Location: June 24, 2026, at ISRO Propulsion Complex (IPRC), Mahendragiri, Tamil Nadu
• Thrust Level: Achieved 175 tonnes (88%) thrust, up from earlier tests at 94 tonnes (47%) and 120 tonnes (60%)
• Engine Systems: PHTA includes all engine subsystems except the thrust chamber
• Performance: Demonstrated successful operation of main turbopumps delivering 400 and 500 bar outlet pressures
• Outcome: All parameters matched predictions, providing confidence for the upcoming 200‑tonne (100%) thrust test

Strategic Importance

• Indigenous Development: Strengthens India’s self‑reliance in advanced propulsion systems
• SC120 Stage: Powered by the 2000 kN‑class SE2000 engine, will replace the current L110 core stage of the LVM3 launch vehicle
• Payload Boost: Expected to substantially increase payload capacity and enhance operational efficiency
• Cleaner Propellants: Uses Liquid Oxygen (LOX) and purified kerosene (isrosene), which are non‑toxic and more efficient

Roadmap for LVM3

• Integration Plan: Semi‑cryogenic propulsion will be paired with an uprated cryogenic upper stage
• Capability Expansion: Enhances LVM3’s payload capacity for heavier satellites and deep‑space missions
• Global Competitiveness: Positions ISRO alongside leading space agencies using semi‑cryogenic systems

Technical Milestones Achieved

Test Phase	Thrust Level	Key Achievements
Initial Tests	94 Tonne (47%)	Validated ignition build‑up
Mid‑Stage Tests	120 Tonne (60%)	Stable operation at higher thrust
Latest Test	175 Tonne (88%)	Turbopumps at 400–500 bar, steady state
Next Target	200 Tonne (100%)	Full engine demonstration

Broader Impact

• National Security & Economy: Enhances India’s ability to launch heavier payloads for defense, communication, and commercial satellites
• Sustainability: Cleaner fuels reduce environmental risks compared to hypergolic propellants
• Global Market: Strengthens India’s competitiveness in the international satellite launch market

This achievement is a critical step in ISRO’s roadmap toward advanced propulsion systems and expanded launch capabilities.