The Indian Space Research Organisation (ISRO) has reached a significant milestone in its space propulsion roadmap with the successful third hot test of its SE2000 semi-cryogenic engine. Conducted on May 28, 2025, at the ISRO Propulsion Complex (IPRC) in Mahendragiri, this test is a major step toward upgrading India’s heaviest rocket, the LVM3, to enhance its payload capacity and mission flexibility by 2027.

Key Highlights

Third hot test of SE2000 engine completed on May 28, 2025

Engine part of upgrade plan to replace LVM3’s current L110 stage

SE2000 will power SC120 stage with enhanced thrust and efficiency

Expected payload boost: up to 10 tonnes to LEO and 5 tonnes to GTO

ISRO aims for full integration and flight-readiness by 2027

The SE2000: A Game-Changer in Indian Rocketry

The SE2000 is a 2000 kN-class semi-cryogenic engine designed to operate on an oxidizer-rich staged combustion cycle, utilizing liquid oxygen (LOX) and refined kerosene (RP-1). This is a shift from the current hydrazine-based L110 stage, bringing significant improvements in performance, efficiency, and sustainability.

The engine is capable of producing:

Chamber Pressure: 180 bar

Specific Impulse: 335 seconds

Thrust Class: 2000 kN

These metrics position SE2000 among the high-performance engines in the global commercial launch market.

A Look at the Three-Phase Hot Test Campaign ISRO’s SE2000 development has involved a careful step-by-step testing process of the Power Head Test Article (PHTA), focusing on the engine’s critical components like:

Low and high-pressure turbo pumps

Pre-burner ignition systems

Start-up sequencing

Control and regulation systems

First Test – March 28, 2025

Duration: 2.5 seconds

Goal: Validate smooth ignition and bootstrap sequence

Second Test – April 24, 2025

Duration: 3.5 seconds

Goal: Demonstrate start transient and full ignition ramp-up

Third Test – May 28, 2025

Duration: 3 seconds

Goal: Fine-tune and finalize ignition and start-up protocol

These tests did not include the full thrust chamber, allowing ISRO to focus on core propulsion logic and subsystems validation before proceeding to integrated tests.

The SC120 Stage: Powering the Future of LVM3 The SE2000 engine will power the SC120 upper stage, which is expected to replace the existing L110 liquid core stage in the LVM3 (Launch Vehicle Mark-3). With this upgrade:

LEO Payload Capacity: Increased from ~8 tonnes to ~10 tonnes

GTO Payload Capacity: Increased from ~4 tonnes to ~5 tonnes

This will make the LVM3 far more competitive for commercial satellite launches, interplanetary missions, and even future crewed spaceflight.

Why SE2000 Matters: Strategic and Commercial Implications

The development of the SE2000 engine holds substantial implications for India’s space ambitions:

Reduced Dependence on Foreign Engines: Semi-cryogenic propulsion is a long-pursued goal for ISRO to move beyond traditional liquid fuels.

Reusable Launch Vehicles: The engine’s high performance could be pivotal in ISRO’s work on RLV-TD (Reusable Launch Vehicle Technology Demonstrator).

Gaganyaan Support: A more powerful LVM3 opens up possibilities for crewed deep space missions.

Commercial Boost: Enhanced payload capacity strengthens India’s ability to compete in the global commercial satellite market.

What’s Next for ISRO?

With the successful completion of subsystem tests, ISRO will now transition to full engine integration trials. Once validated, the SC120 stage will begin qualification for future LVM3 missions, with a potential first flight by 2027.

This progress aligns with ISRO’s broader vision to increase the frequency, capability, and versatility of its launch vehicles—essential for both national strategic missions and international commercial collaboration.

Conclusion

ISRO’s successful third hot test of the SE2000 engine marks a pivotal advancement in India’s space propulsion program. With plans to integrate the new engine into the LVM3, ISRO is well on its way to launching heavier payloads, enabling more ambitious space missions, and solidifying its role as a key player in the global space economy.