ISRO Successfully Conducts third Hot Test of Semi-Cryogenic Engine Power Head Test Article

Bengaluru. ISRO commenced a series of performance evaluation tests in March 2025 of the Semi-cryogenic engine Power Head Test Article (PHTA) that comprises all the engine systems except the thrust chamber. These tests were planned to validate the design of the propellant feed system, including the low-pressure and high-pressure turbo-pumps, the pre-burner, start system and control components.

On May 28, 2025, the Power Head Test Article (PHTA) underwent a third hot test at the ISRO Propulsion Complex (IPRC), Mahendragiri, that was aimed at validating the engine’s ignition and start-up sequence and to derive optimum sequence for the integrated engine. During the test, the engine was successfully ignited and operated up to 60% of its rated power level, demonstrating stable and controlled performance throughout the firing.

The PHTA has earlier undergone two hot tests. The first test on March 28, 2025, demonstrated the smooth ignition & bootstrap operation over a short duration of 2.5 seconds. The second hot test on April 24, 2025, demonstrated the start transient build up and tested the start-up sequence by carrying out a hot-firing for a duration of 3.5 seconds. The third test, conducted today, was carried out for a duration of 3 seconds to further fine-tune & finalize the start-up sequence.

The Semi-Cryogenic Propulsion Stage (SC120), powered by the 2000 KKN-class SE2000 engine, is being developed to replace the current liquid core stage (L110) of the LVM3 launch vehicle towards enhancing its payload capability.