India's private space sector is on the cusp of a major achievement. Bengaluru-based startup Astrobase Space Technologies announced it will reveal India’s first fully integrated 80-tonne-class Full Flow Staged Combustion (FFSC) rocket engine this Friday.
This unveiling is a significant development for India's burgeoning private space industry and its broader goal of developing reusable launch vehicles. If successful, India will join an exclusive club as only the fourth country, after the Soviet Union, the United States, and China, to test an FFSC rocket engine. Astrobase would also become only the eighth entity globally to achieve this complex feat.
Understanding Full Flow Staged Combustion (FFSC)
FFSC represents one of the most advanced and intricate liquid-propellant rocket engine designs ever conceived. In this configuration, both the fuel and the oxidiser are first directed into separate preburners. Each propellant then passes through its own turbine before entering the main combustion chamber.
This sophisticated process significantly enhances efficiency because the main chamber receives propellants that are already fully gasified, facilitating faster combustion within a more compact chamber. The design also allows turbines to operate at lower temperatures and pressures despite handling higher mass flows, which extends the engine's lifespan and boosts reliability. Furthermore, it eliminates the need for a seal between the fuel and oxidiser sides, reducing potential failure points.
These characteristics make FFSC engines particularly well-suited for reusable rockets, though their design, construction, and successful operation remain among the most challenging engineering tasks in aerospace.
Astrobase's Methalox Engine
Astrobase's engine is inspired by SpaceX's groundbreaking Raptor engine. Like the Raptor, it utilizes liquid oxygen (LOX) as the oxidiser and liquid methane (CH4) as the fuel, a combination commonly referred to as methalox. The company previously achieved a successful hot-fire test of a sub-scale version of this engine in September 2025, paving the way for this full-scale integrated unveiling.
Implications for India's Space Future
The significance of this announcement extends beyond the technological achievement itself. It underscores the growing strength of India's private space ecosystem. Astrobase's engine development has received crucial support through the Technology Adoption Fund (TAF) of the Indian National Space Promotion and Authorisation Centre (IN-SPACe), highlighting the effectiveness of the Centre's policy in fostering private-sector innovation.
This development follows closely on the heels of another milestone: Hyderabad-based Skyroot Aerospace's successful launch of Vikram-1, India's first privately developed orbital-class small-lift launch vehicle, just a month prior. These achievements collectively accelerate momentum within India's rapidly expanding private space industry.
A Rare Technological Mastery
The first FFSC engine variant, the RD-270, was tested by the Soviet company NPO Energomash between 1967 and 1969. For decades, no other such engine was successfully tested. SpaceX broke this dormancy in 2019 with its successful Raptor Methalox engine, which became foundational for the company's reusable rocket and re-entry capabilities.
While five more FFSC engine tests have occurred since then, including by Chinese entities, the Raptor Methalox remains the only FFSC engine to have been successfully used in orbital flight launches. If Astrobase's upcoming engine performs as anticipated, it will firmly position India among a select group of nations that have mastered one of the world's most challenging rocket engine technologies, further solidifying the country's ambitions in reusable launch systems and private spaceflight.