ISRO Sets New Benchmark with Successful Semi-Cryogenic Engine (SE2000) Test for LVM3

By R Anil Kumar

ISRO’s recent successful hot test of the Power Head Test Article (PHTA), part of the SE2000 semi-cryogenic engine development, is a significant step towards enhancing the LVM3 launch vehicle’s capabilities. This engine, when fully developed, will power the SC120 stage, replacing the existing L110 liquid core and increasing the LVM3’s payload capacity. The SE2000 engine uses liquid oxygen and kerosene, offering advantages over the current hydrazine-based system, including improved performance and reduced toxicity.

The Indian Space Research Organisation (ISRO) has achieved a significant milestone in its space launch capabilities with the successful completion of the third hot test of its semi-cryogenic engine, the SE2000, on May 28, 2025.

Conducted at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu, this test marks a pivotal advancement in the development of the SC120 stage, which will eventually replace the current L110 liquid core stage of the LVM3 heavy-lift launch vehicle.

The SE2000 engine, designed to deliver a high thrust of 2000 kN, employs an oxidizer-rich staged combustion cycle using liquid oxygen and kerosene—propellants that are both non-toxic and non-hazardous.

This innovative combination allows the engine to achieve a chamber pressure of 180 bar and a specific impulse of 335 seconds, offering a substantial performance upgrade over the hydrazine-based propulsion system of the L110 stage.

The use of these propellants not only improves operational efficiency but also aligns with global trends in environmentally safer and more cost-effective rocket technology.

The recent hot test is the third in a series of phased trials for the Power Head Test Article (PHTA), which includes all engine systems except the thrust chamber.

The first test, conducted on March 28, 2025, demonstrated smooth ignition and bootstrap operation for 2.5 seconds. The second test on April 24, 2025, focused on the start-up transient build-up and lasted 3.5 seconds. The latest, third test ran for 3 seconds, successfully igniting the engine and operating it up to 60% of its rated power, with stable and controlled performance throughout.

These tests have validated critical subsystems such as turbo-pumps, the pre-burner, start system, and control components, ensuring the engine’s reliability for future missions.

With subsystem validations complete, ISRO is now preparing for integrated engine-level trials. The SC120 stage, powered by the SE2000 engine, is expected to significantly enhance the LVM3’s payload capacity—raising the Geostationary Transfer Orbit (GTO) capability from 4 to 5 tons and the Low Earth Orbit (LEO) capacity from 8 to 10 tons.

This improvement will not only enable India to launch heavier satellites but also strengthen the country’s competitive position in the global space launch market, supporting more ambitious missions, including lunar and potential crewed spaceflights.

ISRO’s achievement with the SE2000 engine underscores its commitment to technological innovation and self-reliance in advanced rocket propulsion.

The successful integration of the SC120 stage is anticipated to enter operational service by 2027, marking a new era for India’s space program and reinforcing its status as a major player in space exploration and satellite deployment.

Key aspects of the successful test:

Third Hot Test:

The PHTA, containing all engine systems except the thrust chamber, underwent three successful hot tests, with the latest on May 28, 2025.

Ignition and Start-up:

The tests validated the engine’s ignition and start-up sequence, demonstrating stable and controlled performance.

Performance Validation:

The PHTA’s performance was evaluated to fine-tune the start-up sequence and optimize the integrated engine performance.

SE2000 Engine:

The semi-cryogenic SE2000 engine will power the SC120 stage, which will replace the L110 stage on the LVM3.

Increased Payload Capacity:

The new stage will increase the LVM3’s Geostationary Transfer Orbit (GTO) capacity from 4 to 5 tonnes and its Low Earth Orbit (LEO) capacity from 8 to 10 tonnes.

Benefits of Semi-Cryogenic:

Semi-cryogenic engines, using liquid oxygen and kerosene, offer advantages in terms of simplicity, cost-effectiveness, and increased thrust compared to fully cryogenic engines.

This successful test marks a major milestone in ISRO’s efforts to enhance the LVM3’s capabilities and pave the way for future space missions.

About IPRC

The ISRO Propulsion Complex (IPRC) at Mahendragiri in Tamil Nadu is the primary test hub for ISRO’s liquid propulsion systems. It houses a multi-engine test facility, including the Semi-cryogenic Integrated Engine Test (SIET) complex, which is crucial for testing semi-cryogenic engines and stages. This facility is capable of testing engines with thrust levels up to 2600 kN and is designed to handle large flows of propellants

Key Features of the Multi-Engine Test Facility at IPRC:

SIET Complex:

This is a 51-meter tall facility designed for testing semi-cryogenic engines and stages.

Cryo-Main Engine Static Test Facility (CMEST):

Used for testing ISRO’s cryogenic engines, particularly the CE-7.5 and CE-20.

High Altitude Test Facility (HATF):

Used for hot testing cryogenic engines in vacuum conditions.

Principal Test Stand (PST):

The oldest facility, designed for testing the Vikas engine and other hypergolic engines.

Importance of the Facility:

Validation of Engine Performance:

The facility enables ISRO to validate the performance of semi-cryogenic engines and other propulsion systems.

Development of Indigenous Cryogenic Technology:

IPRC plays a key role in the development of indigenous cryogenic engines for launch vehicles like GSLV and LVM 3.

Support for Interplanetary Missions:

The facilities are also used for developing propulsion systems for interplanetary missions.

Testing of Subsystems:

IPRC conducts testing of various subsystems, including pre-burners, turbo pumps, and start systems.

Qualification and Acceptance Testing:

A Semi-cryogenic Cold Flow Test facility (SCFT) has been established for the development, qualification, and acceptance testing of semi-cryogenic engine subsystems.

(Images Source: ISRO)