The development program of the 110-ton thrust class LOX-Methane rocket engine has officially advanced into its testing phase, marking a major milestone in next-generation propulsion systems. The initiation of hot-fire testing confirms successful completion of extensive design validation, subsystem qualification, and ground-based hardware trials, ensuring the engine’s readiness for full-scale evaluation.

The engine operates on a liquid oxygen (LOX) and liquid methane propellant combination, chosen for its performance efficiency, operational simplicity, and suitability for reusability. Unlike traditional kerosene systems, methane burns cleaner, reducing carbon deposition (coking) inside combustion chambers and turbo-machinery.

Compared to cryogenic hydrogen, methane allows easier handling, higher density storage, less stringent thermal insulation requirements, and greater compatibility with reusable stage turnarounds. The 110-ton thrust rating puts this engine in a strategic performance bracket capable of powering heavy-lift vehicles and large orbital stages while still addressing future needs for cost-effective multi-launch missions.

The testing campaign currently underway will include a rigorous series of evaluations, beginning with ignition trials, low-duration burns, and then scaling up to full-duration high-thrust firings.

Testing Methodology

1. Initial Phase Testing

Testing began with ignition trials and short-duration burns to validate safe and stable start-up sequences. Attention has been directed toward injector dynamics, combustion chamber pressure build-up, and ignition reliability under varying operational conditions.

2. Intermediate Phase

The next phase involves expanded burn durations to stress-test the turbo-pumps, verify cooling system integrity, and evaluate transient phenomena such as throttle variations and restart capabilities. Chamber pressures and propellant flow rates are being extensively monitored, using high-precision instrumentation to build a robust performance matrix.

3. Final Qualification Tests

The concluding phase of engine testing will involve full-duration firings simulating actual mission-length operation at peak thrust levels. Exhaust analysis, vibration profiling, and system endurance tests will form part of this stage, certifying the engine for integration into the upcoming rocket stage.

The program aims to validate combustion stability, thermal resilience of critical components, injector performance, turbo-pump operation, ignition sequences, start-stop reliability, and long-duration burn characteristics simulating an actual mission profile.

Over the next three months, these iterative tests will be expanded toward achieving the first fully developed version of the 110-ton class engine.

Engineers are also integrating advanced instrumentation and data acquisition systems to measure chamber pressures, thrust efficiency, propellant flow rates, and structural vibrations, ensuring that the engine meets required safety factors and optimised performance margins.

The timeline indicates that the fully developed engine will be ready within the next three months, followed by qualification and flight readiness evaluations, with the expectation that the mature design will be available by next year. Preparations are also underway for the parallel development of an entire rocket stage built around the LOX-Methane propulsion system.

This stage is envisioned to not only serve as a key upper-stage or booster option for future launch vehicles but also to enable long-term goals such as reusability, reduced operational costs, and missions optimised for interplanetary exploration where in-situ methane production could play a role.

Engineering teams are expected to begin work on stage design, structural integration, tankage, and stage-level testing soon after engine validation milestones are completed.

This achievement demonstrates the rapid progress being made in indigenous advanced propulsion technology, positioning the program as a frontrunner in methane-based rocket development.

If successful, the LOX-Methane powered stage will significantly enhance mission versatility and provide a scalable pathway for future heavy-lift and reusable launch vehicles.

Together, the ongoing full-scale engine development and the planned rocket stage integration reflect a transformative leap toward sustainable, high-performance spaceflight capabilities.

ISRO