ISRO has completed the design phase of a powerful 2,400 kN liquid oxygen-liquid methane (LOX-methane) rocket engine based on the Full-Flow Staged Combustion Cycle (FFSCC).

The engine is intended to power a future heavy-lift, human-rated launch vehicle that will support India's planned crewed lunar landing missions.

The newly designed engine forms part of ISRO's long-term strategy to develop advanced propulsion systems for future exploration programs, including human missions beyond Earth orbit. The organisation has identified LOX-methane propulsion as a key technology for both the Next Generation Launch Vehicle (NGLV) and a future heavy-lift launcher targeted at lunar operations.

The Full-Flow Staged Combustion Cycle is regarded as one of the most advanced rocket engine architectures currently under development worldwide. The cycle offers improved propellant efficiency, enhanced performance and greater suitability for reusable launch systems, although it also demands highly sophisticated engineering and manufacturing capabilities.

Methane-fuelled rocket engines are attracting increasing global interest because they deliver cleaner combustion than many conventional propellants, reducing residue build-up and potentially lowering maintenance requirements. The propellant combination is also considered attractive for future deep-space missions due to the possibility of producing methane from local resources on planetary bodies such as Mars.

ISRO began dedicated LOX-methane propulsion development work in 2019 to gain operational experience with the propellant combination. As part of these efforts, the agency developed the LM20-TD technology demonstrator engine by modifying subsystems from the CE-20 cryogenic engine.

The LM20-TD demonstrator underwent a cold-flow test and multiple successful hot-fire tests at the ISRO Propulsion Complex. These trials provided valuable data on engine start-up behaviour, ignition characteristics, combustion performance, rotor dynamics and propellant management.

Alongside the 2,400 kN engine program, ISRO is progressing work on the 1,100 kN LME1100 LOX-methane engine, which uses a gas-generator cycle. The integrated LME1100 engine is expected to undergo further qualification testing as development advances.

Completion of the 2,400 kN engine design represents a significant milestone in India's efforts to develop indigenous heavy-lift launch capabilities. Once developed, tested and certified, the engine is expected to play a central role in future human spaceflight missions, including the country's ambition to land astronauts on the Moon around 2040.

ISRO