Astrobase unveils 800kN rocket engine, eyes reusability
A Bengaluru-based private space company unveiled an 800 kN-class liquid oxygen-methane rocket engine, described as India's first privately developed Full-Flow Staged Combustion (FFSC) engine
The engine is intended to power a partially reusable, medium-lift launch vehicle, with a cluster of seven engines planned for the first stage
The company aims for hot-fire testing to begin shortly, targeting a first orbital flight by December 2028
Development has drawn support through IN-SPACe's Technology Adoption Fund, part of India's post-2020 private space sector framework
Full-Flow Staged Combustion (FFSC) Cycle — Rocket Engine Architecture
Rocket engines are classified by how they route propellant through the combustion process. In a full-flow staged combustion cycle, both the fuel and the oxidiser are fully vapourised in separate preburners before entering the main combustion chamber — unlike simpler gas-generator cycles (used in ISRO's Vikas engine) where a fraction of propellant is burned off and exhausted rather than reused, or conventional staged combustion (used in some Russian engines) where only one propellant is fully gasified. FFSC allows very high chamber pressures and efficiency while running the turbopumps at lower temperatures, improving engine life and reusability, but the engineering complexity is extreme.
Key Details
- The only previously operational FFSC engine is SpaceX's Raptor (methalox, used on Starship); the Soviet RD-270, developed in the 1960s for the UR-700 vehicle, attempted FFSC but never flew
- ISRO's own liquid engines — Vikas (used on PSLV/GSLV) and CE-20 (cryogenic, used on LVM3) — use gas-generator and staged-combustion cycles respectively, not full-flow staged combustion
- Propellant choice — liquid oxygen and methane ("methalox") — is favoured for reusable vehicles because methane burns cleaner than kerosene (less coking/residue on reused engine parts) and can theoretically be produced from Martian atmospheric resources for future deep-space missions
The unveiling positions the company among a very small global group — alongside the US — to have developed an FFSC-cycle engine, a technology central to next-generation reusable launch vehicles.
India's Private Space Sector Reforms and IN-SPACe
India's space sector was opened to private participation across all activities — satellite building, launch vehicle manufacturing, and ground infrastructure — through Cabinet-approved reforms in June 2020. The Indian National Space Promotion and Authorisation Centre (IN-SPACe) was set up as an autonomous, single-window regulatory body under the Department of Space to authorise and support private/non-governmental space entities, operating independently of ISRO's own operational missions.
Key Details
- IN-SPACe established 2020, under the Department of Space, as the regulator-cum-promoter for private space activity
- NewSpace India Limited (NSIL), a public sector undertaking also created in the reform period, handles commercial transfer of ISRO-developed technology and commercial launches
- IN-SPACe's Technology Adoption Fund supports advanced propulsion and launch vehicle development by private firms
- Other private Indian launch vehicle developers include Skyroot Aerospace (Hyderabad; solid-fuel Kalam-250 engine on Vikram-I) and Agnikul Cosmos (incubated at IIT-Madras; Agnilet, the world's first single-piece 3D-printed semi-cryogenic engine, first suborbital flight May 2024)
The engine unveiling is a direct outcome of the 2020 reforms and IN-SPACe's promotional mandate, and marks a step up in technical ambition — from solid-fuel and semi-cryogenic engines already flown by Indian private players to a full-flow staged combustion liquid engine aimed at reusability.
Reusable Launch Vehicles and Cost of Access to Space
Reusable launch vehicle technology — recovering and reflying first-stage boosters and/or engines — is the primary lever being used globally to reduce the cost per kilogram of reaching orbit. ISRO's own Reusable Launch Vehicle (RLV) programme has conducted a series of technology demonstrator landing experiments (RLV-TD, 2016 onward; LEX series) toward an eventual Next Generation Launch Vehicle (NGLV).
Key Details
- Engine reusability (rated here for 100+ reuses per unit, per the company) is a key cost driver, since propulsion is among the most expensive and complex subsystems to rebuild after each flight
- ISRO's RLV-LEX (Landing Experiment) series has tested autonomous landing of a winged reusable vehicle at the Aeronautical Test Range, Chitradurga, Karnataka
- Government target: reducing launch cost is central to India's Indian Space Policy 2023, which explicitly encourages non-governmental entities (NGEs) to undertake end-to-end space activities
The engine is designed specifically for a reusable vehicle, aligning private-sector innovation with ISRO's parallel, government-led reusability efforts and the broader Indian Space Policy 2023 goal of commercially competitive, low-cost access to space.
- Engine thrust class: 800 kN (approximately 80-tonne class)
- Propellant combination: liquid oxygen and methane (methalox)
- Cycle: Full-Flow Staged Combustion (FFSC) — only previously flown operationally on SpaceX's Raptor
- Planned configuration: seven engines clustered for a partially reusable, medium-lift launch vehicle
- Targeted first flight: December 2028
- IN-SPACe established: 2020, under the Department of Space, as part of India's private space sector reforms
- Comparable Indian private engines already flown: Skyroot's Kalam-250 (solid-fuel) and Agnikul's Agnilet (3D-printed semi-cryogenic), first flown 2024