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By:

Commodore S.L. Deshmukh

31 October 2024 at 8:30:19 am

The Detonation Race Is On

Rotating detonation engines could redefine propulsion in the near future, and India cannot afford to be a bystander For more than a century, the basic architecture of the jet and rocket engine has remained remarkably resilient. Fuel is burned, gases expand and turbines, compressors or other components turn that energy into thrust. Now, a different idea is beginning to move from laboratories towards operational propulsion: the rotating detonation engine (RDE). It replaces conventional...

The Detonation Race Is On

Rotating detonation engines could redefine propulsion in the near future, and India cannot afford to be a bystander For more than a century, the basic architecture of the jet and rocket engine has remained remarkably resilient. Fuel is burned, gases expand and turbines, compressors or other components turn that energy into thrust. Now, a different idea is beginning to move from laboratories towards operational propulsion: the rotating detonation engine (RDE). It replaces conventional combustion with a continuously travelling supersonic detonation wave, promising greater efficiency in a smaller and mechanically simpler package. If propulsion is a contest between how much energy can be extracted from fuel and how little machinery is required to do it, RDEs have an intriguing advantage. An RDE works inside an annular, or ring-shaped, combustion chamber. Fuel and oxidiser are injected into the chamber and ignited. Instead of a conventional flame moving relatively slowly through the mixture, a detonation wave races around the chamber at supersonic speed. The wave compresses and ignites fresh fuel as it travels, creating a self-sustaining cycle. The resulting high-temperature gases are expelled axially, generating continuous thrust. Improving Fuel Efficiency That is fundamentally different from the combustion process used by traditional engines. Conventional gas-turbine engines operating on the Brayton cycle rely on subsonic deflagration - a rapid burning process in which the flame front travels through the combustible mixture at less than the speed of sound. RDEs generally operate on the Humphrey cycle, using pressure-gain combustion to extract more useful energy from the chemical reaction before the gases are expelled. Detonation-based combustion has the potential to improve fuel efficiency by as much as 25 percent compared with conventional engines. RDEs can also dispense with some of the heavy and complicated moving machinery associated with traditional propulsion systems. That creates the possibility of engines that are smaller, lighter and easier to manufacture. For missiles and rockets, where every kilogram matters, such advantages are particularly valuable. The appeal extends beyond efficiency. A continuously propagating detonation wave can provide steady thrust while eliminating the need for a conventional turbine-compressor architecture. The result could be a propulsion system suited to hypersonic missiles, high-speed aircraft, space vehicles and other platforms where compactness and performance matter as much as raw power. That said, maintaining a smooth and stable detonation wave is extraordinarily demanding. Fuel injection must be precisely controlled and the geometry of the combustion chamber carefully engineered. The number, spacing and shape of injectors can determine whether the detonation remains stable or breaks down. Inside the chamber, extreme temperatures and pressures place enormous demands on engine walls, requiring advanced cooling systems and high-performance materials. These engineering problems explain why the RDE revolution has been promising for years without yet becoming routine technology. The challenge is no longer simply demonstrating that a detonation can be sustained. It is turning that phenomenon into a reliable, durable and flight-ready propulsion system. Production Race The United States is pushing ahead on several fronts. NASA has successfully tested full-scale RDEs producing more than 5,800 pounds of thrust and is planning to raise that figure to 10,000 pounds for potential lunar and Mars missions. Pratt & Whitney, part of RTX, has conducted extensive RDE testing for military applications, exploring high-speed and long-range propulsion with a simpler architecture. DARPA is pursuing RDE technology for hypersonic standoff missiles under its Gambit programme, while L3Harris has conducted long-duration, full-scale tests aimed at advancing next-generation missile propulsion. The international competition is broader still. Japan’s JAXA, GE Aerospace and Chinese institutions have been pursuing RDE applications in rockets and hybrid air-breathing engines, including systems intended for hypersonic flight. China, in particular, is treating the technology as part of its broader push towards high-speed aerospace and military systems. Researchers at Tsinghua University introduced a hybrid design in 2024 combining a ramjet with a rotating rotor compressor, intended to improve starting at lower speeds and enhance performance during flight. In 2025, scientists at the Beijing Power Machinery Research Institute reportedly completed a milestone test of an RDE operating steadily for 180 seconds at Mach 6.3. Recent Chinese test engines have also reportedly incorporated specialised materials capable of tolerating internal temperatures of up to 2,500°C. For India, therefore, RDEs are no longer merely an interesting engineering experiment but are fast becoming part of the strategic propulsion race. India has already taken an important step. Defence propulsion start-up D-Propulse, incubated at IIT Madras, has demonstrated what it describes as the country’s first indigenous 5 kN air-breathing RDE coupled with an aerospike nozzle. The hot-fire demonstration was conducted at a DRDO test facility and reportedly achieved Technology Readiness Level-5 validation in the specified environment. That matters because it represents a movement from laboratory research towards an integrated propulsion prototype. D-Propulse has stated that it is targeting a flight-ready engine by December 2027. The company says its technology can deliver 15–25 percent higher thermodynamic efficiency than conventional air-breathing propulsion systems and can be produced through precision machining rather than complex turbine assemblies, potentially reducing both production costs and lead times. The applications could be considerable. Defence systems could include hypersonic missiles, air-to-air and air-to-ground weapons and compact propulsion systems for standoff strike platforms. In space, RDEs could find uses in upper-stage rocket engines, planetary landers and deep-space propulsion, where higher efficiency and lower engine mass are particularly valuable. The technology could even migrate beyond aerospace: RDE-based gas turbines could potentially generate electricity with greater thermal efficiency and lower fuel consumption. The larger significance is that propulsion technology often determines what a country can build, how far it can travel and how quickly it can respond. RDEs remain an emerging technology, and their promise should not be confused with operational maturity. But countries that solve the problems of stability, materials, cooling and reliable fuel injection first could gain an important advantage in the next generation of aerospace and defence systems. (The writer is a retired naval aviation officer and a defence and geopolitical analyst. Views personal.)

Skills Without a Roadmap

The real skilling challenge facing the country is not producing more certificates but helping young people navigate a fast-changing labour market.

AI generated image
AI generated image

Successive Indian governments have spent years building a skilling ecosystem aimed at preparing the young population for a changing labour market. But the answer to a key question remains elusive: how do young people know which skills they should acquire in the first place?


As technology reshapes occupations and employers’ requirements evolve, choosing the right skill is becoming almost as important as acquiring it. The problem, therefore, is not simply whether someone has been trained, but whether they know what that training is worth in the labour market.


The recent NITI Aayog report ‘Reimagining Skilling for Viksit Bharat@2047’ recognises this gap, highlighting the need for stronger career guidance and closer alignment between skilling and local industry demand. The next phase of India’s skilling revolution, therefore, cannot be about training more people alone. It must also help people understand where those skills can take them.


Meaningful Employment

India’s skilling push has achieved considerable scale. According to NITI Aayog’s recent report, 7.67 crore people have been trained through government skilling initiatives since 2014-15, while Rs. 34,000 crore was allocated to skilling-related expenditure across Central Ministries in 2025-26. Yet scale alone does not tell us whether training is translating into meaningful employment.


A person can complete a course successfully and still find themselves asking the most important question: what comes next? A skill may be valuable in the national economy, but that does not necessarily mean it translates into an opportunity in the local economy.


This is where the conventional idea of skilling falls short. Training is often treated as the endpoint, enrolment, completion and certification become the indicators of success. For a young person entering the labour market, a certificate is only a starting point if it connects them to an occupation, an employer or a pathway for further learning.


The missing layer in India’s skilling ecosystem is not necessarily another training programme. It is career navigation. Telling someone to “learn digital skills” or acquire an “AI skill” does little if they do not know which occupations require those skills, what employers actually look for, or how those skills can translate into long-term career progression. For a young person deciding what to study, this means knowing more than the name of a skill. They need to know which occupations use it, what employers expect from entry-level workers, where those jobs are available and what the likely progression looks like. The advice may sound future-ready, but without context, it leaves the individual to solve the most difficult part themselves: deciding what to learn and why.


This is particularly important as the labour market becomes more dynamic. Skills that are valuable today may evolve rapidly, while entirely new roles can emerge alongside technological change. Young people need access to reliable, updated information throughout their education and working lives.


Trusted Guidance

The NITI Aayog’s report recognises this need by identifying trusted career guidance as an important part of a stronger skilling ecosystem. It proposes expanding counselling beyond formal institutions through community-based hubs and digital tools, while making guidance a continuous part of people’s education, skilling and career journeys.


Instead of asking only, “What skills can we teach?” we need to ask, “How can we help people understand which skills to learn, why they matter and where they can lead?”


If career navigation is to become a meaningful part of India’s skilling ecosystem, it must be connected to better information about the labour market itself. Young people cannot make informed choices if the system does not clearly communicate where demand is emerging, which occupations are growing, what employers are looking for and how these opportunities vary across regions.


This requires stronger feedback loops between employers, skilling institutions and workers. Training providers should be able to respond to changing industry requirements, while career guidance systems should translate this information into choices that individuals can actually understand and act upon. Local labour-market information could be particularly valuable in helping young people identify opportunities within or near their own regions, rather than treating the national labour market as a single, uniform space.


The emphasis also needs to shift from one-time training to continuous transitions. NITI Aayog’s proposals around digital lifelong learning accounts, skill passports and greater integration between education, skilling and employment point in this direction. The goal should be to help workers understand not only what they have already learned, but what they need to learn next.


Ultimately, a demand-driven skilling system should not simply respond to the question of what people need to learn. It should help answer the equally important question of what they can do with what they learn.


India’s skilling challenge is no longer simply about creating access to training. It is about creating access to the right information. As the labour market evolves, young people need to know which skills are in demand, where opportunities exist and how they can build from one skill to the next.


The NITI Aayog report’s emphasis on trusted career guidance and stronger alignment between skilling and industry demand points towards this shift. But turning that vision into reality will require career guidance to become a continuous part of the skilling ecosystem, supported by timely labour-market information and stronger connections between employers, training institutions and workers.


India does not need to choose between skilling more people and guiding them better. It needs to do both. The success of the country’s skilling revolution will ultimately depend on whether those certificates help people find and navigate a meaningful employment.


(The writer is an economics postgraduate from Jawaharlal Nehru University with research interests in economic policy, trade and global governance. Views personal.)

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