New Delhi: A Delhi-based defence startup says it has achieved a milestone in one of the Indian military’s most challenging technological frontiers—propulsion.
D-Propulse conducted a ground test of its indigenous air-breathing Rotating Detonation Engine (RDE) at a Defence Research and Development Organisation (DRDO) facility in Hyderabad on 21–22 July, said founder Saurav Jha.
Developing indigenous engine technologies would strengthen India’s strategic autonomy, as dependence on foreign engine suppliers extends beyond procurement to maintenance, spare parts and upgrades, experts said.
“Propulsion technology [technology that makes a vehicle move forward] is among the most strategic technologies in defence. If a country depends on others for aircraft engines, it also depends on them for maintenance, spare parts and upgrades throughout the platform’s life,” said Ravi Kumar Gupta, former scientist and director at DRDO.
Globally, the are still testing similar technology, with no air-breathing RDE yet publicly deployed in an operational missile or aircraft. An RDE is a next-generation jet engine that uses controlled explosions to produce more thrust while using less fuel.
Unlike conventional jet engines that burn fuel like a steady flame, an RDE works by creating a continuous series of tiny, controlled explosions. This helps it generate more power without using extra fuel, making the engine smaller, lighter and more efficient. In the future, it could be used to power faster drones, missiles, aircraft and rockets.
“An RDE is about 15–25% more efficient than today’s jet engines, ramjets or scramjets,” Jha told Mint. “That means you get higher specific thrust while burning the same amount of fuel.”
During the test, D-Propulse fired an RDE that produced 5 kilonewtons (5,000 newtons) of thrust—the force that pushes a drone or missile forward. Globally, while dozens of institutes run sub-scale (1–2 kN) air-breathing test rigs for fractions of a second, no entity has publicly demonstrated a 5 kN class continuous-thrust air-breathing RDE integrated with an expansion aerospike on a government-certified test facility, claims Jha.
The company plans to conduct its first flight test by December 2027, followed by military user trials by December 2029. The startup expects the Indian military to be its primary customer and aims to become an original equipment manufacturer of RDE-powered systems.
“What makes this a landmark is that although several countries are working on rotating detonation engines, no one has yet fielded an operational system. D-Propulse has demonstrated the technology at TRL-5, meaning the basic technology has been successfully validated,” said Gupta. TRL-5 means the technology has been tested under conditions very similar to those where it will eventually be used, but it is not yet in real-world use.
D-Propulse, founded by Jha and former DRDO scientist Dr. V. Ramanujachari, raised ₹25 crore from Indian Angel Network last year to commercialise the technology. Ramanujachari, one of the pioneers of RDE technology in India, is also the company’s CTO.
Propelling startups
Experts say the development will have an overall positive impact on the startup ecosystem. “It will give a fillip to the and encourage other start-ups and to pursue similar technological goals,” said Kartik Bommakanti, senior fellow for defence and national security at ORF, a Delhi-based think tank.
“It will also introduce more competition, which is likely to strengthen the defence sector by bringing costs down and if all goes well, make India self-reliant in RDE. Aero-engine development is a major engineering hurdle India is yet to overcome, and this latest development augurs well for the future,” Bommakanti added.
Former DRDO chief V.K. Saraswat, who joined D-Propulse as chairman in June, said, “While no other Indian startup is currently working on rotating detonation engines, I expect more (institutions and research centres) to enter the space, just as we’ve seen in spacetech with the success of Skyroot.”
Investors say commercial adoption, though, remains at least two years away. “However, subsystems such as fuel injectors and turbopumps are likely to be commercialised much earlier,” said Abhay Agarwal, founder and fund manager of early-stage venture capital firm Piper Serica Advisors.
According to Mordor Intelligence, the aerospace propulsion systems market was valued at $119.53 billion in 2025 and is expected to grow to $144.86 billion by 2030, at a CAGR of 3.92% during the forecast period.