ISRO Successfully Conducts 175-Tonne Semi-Cryogenic Engine Hot Test for Next-Gen Launch Vehicle

The ISRO semi-cryogenic engine hot test achieved a significant milestone as the Indian Space Research Organisation (ISRO) successfully completed a crucial hot test of its semi-cryogenic engine Power Head Test Article (PHTA) at a thrust level of 175 tonnes, advancing India’s next-generation launch vehicle propulsion technology.

The successful test strengthens ISRO’s efforts to develop more powerful and efficient launch vehicles for future space exploration missions.

The test was conducted at the ISRO Propulsion Complex (IPRC) in Mahendragiri, Tamil Nadu. The successful trial is the eighth in a series of hot tests conducted using the Power Head Test Article, which incorporates all the major systems of the engine except the thrust chamber.

ISRO Semi-Cryogenic Engine Hot Test Reaches 175 Tonnes

The latest test was aimed at studying the engine’s performance during the build-up phase after pre-burner ignition and demonstrating steady-state operation at a significantly higher thrust level.

For the first time, the engine powerhead was operated at 175 tonnes of thrust, representing 88 per cent of its full rated capacity.

Earlier tests had been successfully completed at 94 tonnes (47 per cent thrust) and 120 tonnes (60 per cent thrust). During the latest trial, the engine’s main turbopumps also performed as designed, delivering outlet pressures of 400 and 500 bar.

ISRO said the test progressed exactly as predicted, with all engine parameters remaining within the expected range throughout the firing.

The successful demonstration paves the way for full-scale testing of the 200-tonne engine, a key milestone before operational deployment.

How the New Semi-Cryogenic Engine Will Boost LVM3

The successful demonstration has provided ISRO with the confidence required to proceed towards testing the engine at its full rated thrust of 200 tonnes, bringing the indigenous semi-cryogenic engine programme a significant step closer to completion.

The Semi-Cryogenic Propulsion Stage (SC120), powered by the 2,000-kilonewton-class SE2000 engine, is being developed to replace the existing L110 liquid core stage of the Launch Vehicle Mark-3 (LVM3), India’s heaviest operational launch vehicle.

The upgrade is expected to substantially enhance the rocket’s payload carrying capacity while improving overall performance and operational efficiency.

Unlike conventional propulsion systems, the semi-cryogenic engine uses environmentally cleaner and non-toxic propellants—Liquid Oxygen (LOX) and purified kerosene, known as Isrosene.

Why the Semi-Cryogenic Engine Matters for India’s Space Missions

According to ISRO, integrating the new semi-cryogenic stage with an upgraded cryogenic upper stage will significantly strengthen the LVM3’s capabilities, supporting future high-capacity satellite launches, deep-space exploration missions and India’s expanding human spaceflight programme.

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