SCIENCE

Space

ISRO Successfully Tests Semi-Cryogenic Engine 

• Context: Indian Space Research Organisation successfully conducted the 8th hot test of the Semi-Cryogenic Engine Power Head Test Article (PHTA) on 24 June 2026. 

• The test was carried out at the ISRO Propulsion Complex. 

Power Head Test Article (PHTA)

• PHTA includes all engine systems except the thrust chamber. 
• It is used to validate the engine’s performance before integrating the complete engine. 

Highlights of the 8th Hot Test

• • Successfully tested at 175-tonne thrust (88% of full capacity) for the first time. 

• Previous PHTA tests were conducted at: 94 tonne (47%) thrust, 120 tonne (60%) thrust 

• • Objectives achieved: 
    • Studied engine build up after pre burner ignition. 
    • Demonstrated steady-state operation at higher thrust levels. 
    • Successfully operated the main turbopumps delivering: 

• 400 bar outlet pressure 

• 500 bar outlet pressure 

• All engine parameters performed as predicted. 

Significance of the Test

• Provides confidence for testing the engine at 200-tonne (100%) thrust level. 
• Marks a major milestone in the indigenous development of India’s Semi-Cryogenic Engine. 

Semi-Cryogenic Propulsion Stage (SC120)

• • The SC120 stage is powered by the 2000 kN-class SE2000 engine. 

• It is being developed to replace the existing L110 core stage of the LVM3 launch vehicle. 

• Expected benefits: 
  • Higher payload capacity 
  • Improved operational efficiency 
  • Enhanced launch performance for future missions. 

Propellant Used

• • Uses cleaner, non-toxic propellants: 

• Liquid Oxygen (LOX) as oxidizer. 

• Purified Kerosene (ISROSENE) as fuel. 

• Offers better performance and efficiency compared to conventional propulsion systems. 

Strategic Importance

• Supports ISRO’s roadmap to increase the payload capability of LVM3. 
• Combined with an uprated cryogenic upper stage, the semi-cryogenic propulsion system will significantly enhance India’s heavy lift launch capability. 
• Strengthens India’s self-reliance in advanced rocket propulsion technology and future space missions.

About the Semi-Cryogenic Engine

• A Semi-Cryogenic Engine (SCE) is a type of liquid-fuel rocket engine that uses Liquid Oxygen (LOX) as the oxidizer and refined kerosene (RP-1/ISROSENE) as the fuel.

• The Indian Space Research Organisation is developing a 2000 kN-thrust semi-cryogenic engine to power the core/booster stages of its present and future heavy-lift launch vehicles. 

Advantages of the Semi-Cryogenic Engine

• Better Performance: The combination of LOX and kerosene provides a higher density impulse, enabling rockets to generate more thrust with a compact fuel system. 
• Lower Cost: Refined kerosene is cheaper to produce, transport, and use than liquid hydrogen, making space missions more economical. 
• Easier Storage and Handling: Unlike liquid hydrogen, kerosene can be stored at normal atmospheric temperatures, reducing the complexity of fuel storage and launch operations.