The Author is Former Director General of Information Systems and A Special Forces Veteran, Indian Army

On January 21, 2025, India's Defence Research and Development Organisation (DRDO) achieved another key milestone by successfully completing the ground run for an active-cooled scramjet combustor. This came a few months after India tested its first long-range and indigenously developed hypersonic missile. On November 16, 2024, India tested its long-range hypersonic missile that can deliver various payloads for ranges over 1,500 km. With this, India had demonstrated the capability to build an active cooled scramjet combustor that will be a key to hypersonic vehicles.

India's Defence Research and Development Organisation (DRDO) achieved another key milestone by successfully completing the ground run for an active-cooled scramjet combustor, demonstrating its potential for operational use in hypersonic vehicles

DRDO CARRIED OUT SUCCESSFUL FLIGHT-TRIAL OF INDIA'S FIRST LONG-RANGE HYPERSONIC MISSILE ON NOVEMBER 16, 2024.

Scramjets are air-breathing engines capable of sustaining combustion at supersonic speeds without using any moving parts. A statement issued by the DRDO said, "The ground test of scramjet combustor showcased several notable achievements, demonstrating its potential for operational use in hypersonic vehicles, like successful ignition and stable combustion." Hypersonic weapons are primarily of two categories: one, hypersonic glide vehicles - launched from a rocket that glides to the target, and; two, hypersonic cruise missiles - powered by high-speed, air-breathing engines, or 'scramjets' after acquiring the target.

Unlike ballistic missiles, hypersonic weapons do not follow a ballistic trajectory and can manoeuvre to their destination. Hypersonic cruise missiles can travel at speeds greater than Mach 5, which moves at five times the speed of sound or more than 5,400 km/hr. Hypersonic technology allows a country to fuse extreme speed, manoeuvrability, and low-altitude flight, making them harder to track and detect. India's hypersonic missile test in November 2024 placed it in an elite club of countries comprising the US, Russia, China, and North Korea. Notably, it was President, Dr A.P.J. Abdul Kalam, who had said that the Mark-II version of BrahMos should be a hypersonic cruise missile.

The race for hypersonic weapons is heating up globally. According to the US Department of Defense (DoD), China is the world leader in hypersonic technology, surpassing the US and Russia in developing conventional and nuclear-capable hypersonic weapons. Before India successfully tested its hypersonic missile and scramjet engine, China showcased a new hypersonic glide vehicle, the GDF-600, at the Zhuhai air show. In 2023, China successfully tested its DF-27 intermediate-range ballistic missile (IRBM) with a hypersonic glide vehicle (HGV), which China claims can easily breach US missile defence systems. According to the '2023 China Military Power Report', China's DF-17 HGV-armed medium-range ballistic missile (MRBM) will transform the PLA's missile force. Though designed to carry conventional payloads, it can be armed with nuclear weapons. According to a February 28, 2023 leaked classified report by the US Joint Chiefs of Staff intelligence directorate, China's DF-27 is designed to enhance China's ability to hold targets at risk beyond the Second Island Chain and possesses a high probability of penetrating US ballistic missile defence. A 2021 US Department of Defense (DoD) report said the DF-27 has a range of 5,000-8,000 km, implying it can strike any target in East or Southeast Asia and large parts of the Pacific, including Guam, and its hypersonic glide capability makes it a potential "carrier killer".

According to the US Department of Defense (DoD), China is the world leader in hypersonic technology, surpassing the US and Russia in developing conventional and nuclear-capable hypersonic weapons

US Army and Navy Successfully Test Conventional Hypersonic Missile.

On December 12, 2024, the US successfully conducted the end-to-end flight test of a conventional hypersonic missile, The test was a joint effort by the US Army's Rapid Capabilities and Critical Technologies Office and the US Navy Strategic Systems Programs. Called "Dark Eagle' this Long-Range Hypersonic Weapon (LRHW), this test was the culmination of over two years of effort to deploy the weapon from its trailer-based launcher. The missile is designed to defeat advanced 'Anti-Access/Area Denial capabilities. Officially, America's hypersonic weapons are to be conventionally armed. The US Congress contends that American hypersonic weapons are likely to require greater accuracy and be more technically challenging to develop than nuclear-armed Chinese and Russian systems. However, in Donald Trump's second presidency, with Elon Musk pushing to overhaul the US war machine, future US hypersonic missiles will obviously also be nuclear-capable as development of US hypersonic weapons progresses.

The indigenous development of endothermic scramjet fuel, the first time in India, jointly by DRDL and Industry, offers dual benefits of significant cooling improvement and ease of ignition

Russia's hypersonic weapons inventory includes the 3M22 Zircon, Avangard HGV, Kh-95 long-range hypersonic cruise missile, air-launched Kh-47M2 Kinzhal hypersonic missile and the Vympel R-37M. Russia loaded its Sarmat intercontinental ballistic missile (ICBM) with nuclear-capable Avangard HGV and is allegedly using its Zircon hypersonic missile, as well as the new Oreshnik hypersonic missile in the Ukraine war. On January 24, 2025, US President Donald Trump accused Moscow of stealing hypersonic missile design during Barack Obama's administration. "Russia stole the design, they got it from us," Donald Trump said in an interview with Fox News, alleging that "some bad person gave them the design." He also was optimistic that the US would have super hypersonic missiles, which would be even better. "We'll have them starting fairly shortly," he added. This was perhaps a political statement by Trump, because Russia stole American hypersonic technology, why is the US so far behind in hypersonic weapons?

On January 6, 2025, North Korea tested a new intermediate range hypersonic missile. The missile flew about 1,500 km at Mach 12, reaching an altitude of nearly 100 km before descending to a 'second peak; of 42.5 km and manoeuvring to hit a target in the sea off the country's east coast. New carbon fibre composite materials were used in the missile's engine section, which North Korea says can effectively penetrate any dense defence barrier and inflict a serious military blow on the opponent. Carbon fibre is lighter and stronger than other aerospace materials such as aluminium, but is more difficult to manufacture.

BrahMos-II hypersonic cruise missile

India's hypersonic inventory includes the BrahMos-II, HGV-202F, the Hypersonic Technology Demonstrator Vehicle, and the Long-Range Anti-Ship Missile (LRAShM). With reference to the scramjet engine, the DRDO has said that ignition in a scramjet engine is like 'keeping a candle lit in a hurricane. DRDO further said that the scramjet combustor uses a cutting-edge flame stabilisation method that maintains a constant flame inside the combustor at air speeds of more than 1.5 km/s. According to the statement, several innovative and promising ignition and flame-holding approaches were investigated through several ground tests to arrive at the scramjet engine layout. "The indigenous development of endothermic scramjet fuel, the first time in India, jointly by DRDL and Industry, is central to this breakthrough. The fuel offers dual benefits of significant cooling improvement and ease of ignition," the DRDO said. India has also developed a new, advanced ceramic Thermal Barrier Coating (TBC) with high thermal resistance that can operate beyond the melting point of steel.

Finally, India must continue its focus on developing hypersonic weapons in order to catch up with China. The challenge includes development of hypersonic unmanned aerial vehicles.