Hyderabad-based Stardour Aerospace has fired the country’s first privately developed liquid-oxygen/liquid-hydrogen (LOx–LH₂) engine, a step that shifts India’s emerging space economy toward cleaner in-orbit mobility.

The static test at the Indian Institute of Science (IISc), Bangalore, validated a 1 kN-class thruster that burns cryogenic hydrogen and oxygen to produce nothing more than water vapour, marking a decisive break from toxic hypergolic propellants traditionally used on orbital transfer stages.

Unlike cryogenic upper stages that ignite only once in flight, Stardour’s thruster is built for multiple restarts, enabling complex manoeuvres long after a primary launch vehicle has completed its ascent. Engineers integrated a coaxial injector, ablative chamber liner and lightweight composite tanks into a single test article, demonstrating start-up transients, steady-state burn and safe shutdown in a three-minute firing sequence at IISc’s rocket-grade test stand. Data showed combustion efficiency above 95%, chamber pressures near design limits and stable mixture ratios across the throttle band—results that cleared the engine for qualification firing later this year.

The engine will power Lucas, Stardour’s modular orbital transfer vehicle (OTV)—often called a “space tug”—slated for inaugural flight in the third quarter of 2027. Lucas is being designed to pick up satellites deployed in an initial rideshare orbit and haul them to their operational slots in Low-Earth Orbit, Geosynchronous Transfer Orbit and even cis-lunar trajectories, while also performing life-extension, debris-removal and in-orbit refuelling tasks. Early mission studies quote a delta-V budget above 2 km s⁻¹ with payload capacities of several hundred kilograms, figures made feasible 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 underlines the value of academia-startup collaboration. IISc provided vacuum-rated feed systems, high-speed diagnostics and safety oversight, while Stardour supplied design, hardware and instrumentation. Professor Pratikash Panda of IISc hailed the shot as proof that private ventures can leverage national laboratories to “compress development cycles without compromising rigour”. That partnership model echoes recent ISRO policy reforms that open government facilities to start-ups under IN-SPACe authorisation.

Founded in 2020 by former ISRO scientist Rama Rao and entrepreneur Sankarsh Chanda, Stardour operates in stealth mode yet has grown a 40-person team specialising in cryogenic propulsion, guidance software and autonomous operations. The company remains bootstrapped but is courting strategic investors to finance the Lucas flight programme, which will require a qualification stack, a demo mission on a commercial launch vehicle and orbital propellant loading infrastructure.

Stardour’s milestone arrives as India’s private space sector is accelerating: Skyroot’s methane engines, Agnikul’s 3D-printed semi-cryogenic stages and Pixxel’s hyper-spectral satellites have all moved from concept to hardware within five years.

By venturing beyond launchers to the “in-between” layer of in-space logistics, Stardour fills a crucial gap in the domestic ecosystem and keeps India competitive with European and US firms already fielding OTVs.

Looking ahead, the startup must scale thrust levels, complete vacuum qualification and integrate avionics before Lucas can fly in 2027. It also faces the hard economic test of closing a business case around rideshare tug services and life-extension contracts. Yet the successful IISc firing—achieved with indigenous hardware and minimal capital—suggests the technical foundations are sound.

In sum, Stardour’s LOx–LH₂ engine test is more than a laboratory success; it signals the arrival of truly sustainable, private Indian propulsion technology poised to reshape how satellites move, service and retire in orbit. If Lucas launches on schedule, India could become a net exporter of green in-space logistics within the decade, reinforcing its stature as a full-spectrum spacefaring nation.

IDN (With Agency Inputs)