Context: Indian Space Research Organisation has successfully conducted the second short duration hot test of the Lox Kerosene 2,000 kiloNewton (kN) semi-cryogenic engine (SE2000). Earlier, the first major hot test of the engine was conducted in March 2025.
During the test, the engine was successfully ignited and operated up to 60% of its rated power level, demonstrating stable and controlled performance.
Relevance of the Topic: Prelims: Key Facts about Semi-cryogenic Engine; Cryogenic Engine.
ISRO’s Semi-cryogenic Engine
- The Liquid Propulsion Systems Centre of ISRO is developing the Semi cryogenic propulsion Engine and Stage (SC120).
- The stage (SC120) is powered by the 2000 kN semi-cryogenic engine (SE2000). It uses a Liquid Oxygen and Kerosene-based propulsion system that offers an enhanced thrust of 2,000 kiloNewton.
- It will replace the present core liquid stage (L110) (which uses Vikas engine) in Launch Vehicle Mark-3 (LVM3).
Evaluation Tests on Semi-cryogenic Engine:
- Before the full integration of the SE2000 engine, ISRO conducted a series of performance evaluation tests on intermediate configurations.
- Pre-Burner Ignition Test Article (PITA): Tests the ignition process of the engine’s pre-burner. The successful test lasted 2.5 seconds, demonstrating the smooth ignition and operation of the engine.
- Power Head Test Article (PHTA): Validates the integrated performance of an engine's critical subsystems, including the gas generator, turbo pumps, pre-burner and control components. It involves performing a hot-firing of the engine for an extremely brief duration of not more than 4.5 seconds.
- All critical parameters performed as expected, marking a major breakthrough in the semi-cryogenic engine development program.
Benefits of Semi-cryogenic Propulsion System:
- Non-toxic and non hazardous propellants (Liquid Oxygen and Kerosene) are employed in Semi cryogenic propulsion. This will deliver higher performance compared to the existing L110 stage.
- Induction of the Semi cryogenic propulsion system along with an uprated cryogenic stage in the LVM3 vehicle enhances its payload capability from 4 tonne to 5 tonne in GTO (Geosynchronous Transfer Orbit).
Advantages of Semi-cryogenic Engine over Cryogenic Engine:
- Cryogenic engines use liquid oxygen and liquid hydrogen. Handling liquid hydrogen is challenging, as it needs to be stored at minus 253 degrees Celsius, and is highly inflammable.
- A semi-cryogenic engine uses a liquid oxygen – kerosene combination, where kerosene is readily storable. This combination offers advantages like high-density impulse (with respect to cryogenic engines), less toxic (with respect to fuel storage) and is cost-effective.
Significance: The success of the test brings ISRO a step closer towards enhancing the payload capacity of India's LVM3 rocket and strengthening the country's capabilities in space launch vehicles.