ISRO Successfully Conducts Third Hot Test Of Semi-Cryogenic Engine Power Head

In a significant stride towards boosting India’s heavy-lift launch capabilities, the Indian Space Research Organisation (ISRO) successfully carried out the third hot test of its semi-cryogenic engine Power Head Test Article (PHTA) on 28 May 2025 at the ISRO Propulsion Complex (IPRC), Mahendragiri.

The test is part of a series of performance evaluations aimed at validating key subsystems of the engine that will eventually power the SC120 propulsion stage intended to replace the existing L110 liquid core stage of the LVM3 launch vehicle, according to the official release.

The PHTA, comprising all systems except the thrust chamber, includes the propellant feed system, low and high-pressure turbo-pumps, pre-burner, start system, and control components.

“During the test, the engine was successfully ignited and operated up to 60 per cent of its rated power level, demonstrating stable and controlled performance throughout the firing,” the release stated.

The PHTA had earlier undergone two successful hot tests. The first, conducted on 28 March, demonstrated smooth ignition and bootstrap operation for 2.5 seconds.

The second, on 24 April, lasted 3.5 seconds and evaluated start-up sequence and transient build-up. The latest 3-second test aimed at further refining the ignition and start-up sequence of the integrated engine.

The semi-cryogenic engine under development is a 2000 kN-class SE2000 engine. Unlike fully cryogenic engines that use both fuel and oxidiser in a cryogenic (super-cooled liquid) state, a semi-cryogenic engine uses a cryogenic oxidiser, typically liquid oxygen (LOX), and a room-temperature hydrocarbon fuel such as RP-1 (refined kerosene).

This combination offers advantages in terms of simplicity, cost-effectiveness, and increased thrust, making it ideal for the core stage of heavy-lift launch vehicles.

With the successful tests, ISRO moves closer to deploying the SC120 stage on the LVM3, significantly enhancing the vehicle’s payload capacity for future missions.

Also Read: India Sees Gradual Rise In COVID-19 Cases; Centre Urges Vigilance, Not Panic