Stardour Aerospace, located in Hyderabad, has launched India’s first privately developed liquid-oxygen/liquid-hydrogen (LOx-LH₂) engine. This marks a transition in India’s burgeoning space economy towards cleaner in-orbit mobility.
The static test at the Indian Institute of Science (IISc) in Bangalore confirmed a 1 kN-class thruster that burns cryogenic hydrogen and oxygen to create only water vapour, marking a significant departure from hazardous hypergolic propellants previously employed on orbital transfer stages.
Unlike cryogenic upper stages, which ignite only once in flight, Stardour’s thruster is designed for numerous restarts, allowing intricate maneuvers long after a main launch vehicle has finished its ascent. Engineers combined a coaxial injector, an ablative chamber liner, and lightweight composite tanks into a single test article to demonstrate start-up transients, steady-state burn, and safe shutdown in a three-minute firing sequence at IISc’s rocket-grade test stand. The data showed combustion efficiency above 95%, chamber pressures around design limits, and steady mixture ratios across the throttle band, clearing the engine for qualification firing later this year.
The engine will power Lucas, Stardour’s modular orbital transfer vehicle (OTV)—also known as a “space tug”—which is set to take off in the third quarter of 2027. Lucas is intended to pick up satellites in an initial rideshare orbit and transport them to operational slots in Low-Earth Orbit, Geosynchronous Transfer Orbit, and even cis-lunar paths, as well as conduct life extension, debris removal, and in-orbit refueling operations. Early mission studies suggest a delta-V budget above 2 km s⁻¹ and payload capacities of several hundred kilograms, made possible by the high specific impulse of the LOx-LH₂ cycle.
Hydrogen-oxygen propulsion is not merely efficient; it is inherently green, emitting only water and avoiding the carcinogenic exhaust of hydrazine or UDMH systems that dominate many current space-tugs.
In an era of proliferating satellite constellations—where thousands of small spacecraft will vie for limited orbital slots—regulators and operators alike see environmental stewardship as a prerequisite for sustainable growth. Stardour’s approach aligns with this trend and positions India alongside the few nations developing commercially viable cryogenic-hydrogen mobility platforms.
The test also demonstrates the importance of academic-startup collaboration. IISc offered vacuum-rated feed systems, high-speed diagnostics, and safety monitoring, whilst Stardour provided design, hardware, and instrumentation. Professor Pratikash Panda of IISc praised the shot as evidence that private businesses may use national laboratories to “shorten development cycles without sacrificing rigour.” That collaboration concept is similar to recent ISRO policy amendments that allow start-ups to use government facilities under IN-SPACe authorization.
Stardour, founded in 2020 by former ISRO scientist Rama Rao and entrepreneur Sankarsh Chanda, operates under the radar but has developed to a 40-person team specializing in cryogenic propulsion, guiding software, and autonomous operations. The business is still bootstrapped, but it is looking for strategic partners to fund the Lucas flight program, which will include a qualification stack, a demo mission on a commercial launch vehicle, and orbital propellant loading infrastructure.
Stardour’s milestone comes as India’s commercial space sector accelerates: Skyroot’s methane engines, Agnikul’s 3D-printed semi-cryogenic stages, and Pixxel’s hyper-spectral satellites all went from concept to hardware in five years.
By expanding beyond launchers to the “in-between” layer of in-space logistics, Stardour fills a critical vacuum in the domestic ecosystem and maintains India competitive with European and US enterprises that already operate OTVs.
Looking ahead, the startup needs increase thrust levels, complete vacuum validation, and incorporate avionics before Lucas can fly in 2027. It also faces the difficult economic challenge of creating a business case for ridesharing tug services and life-extension contracts. However, the successful IISc firing—achieved using domestic gear and minimal capital—indicates that the technical foundations are solid.
Stardour’s LOx-LH₂ engine test marks the introduction of sustainable, private Indian propulsion technology that will transform how satellites travel, service, and retire in space. If Lucas launches on schedule, India may become a net exporter of green in-space logistics within a decade, cementing its position as a full-spectrum spacefaring nation.
