The global race for hypersonic munitions has been intensifying. On January 21, India successfully completed a ground run for an active-cooled scramjet combustor. This key milestone for India comes a couple of months after it tested its first long-range and domestically developed hypersonic missile.
The test launch of the long-range hypersonic missile that can deliver various payloads for ranges over 1500 km was done on November 16, 2024. With this, India’s Defense Research and Development Organisation (DRDO) has demonstrated the capability to build an active cooled scramjet combustor that will be a key to hypersonic vehicles.
Hypersonic technology allows a country to fuse extreme speed, maneuverability, and low-altitude flight, making them harder to track and detect. Unlike ballistic missiles, hypersonic weapons do not follow a ballistic trajectory and can maneuver 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.
There are two primary categories of hypersonic weapons: Hypersonic glide vehicles launched from a rocket before gliding to a target and Hypersonic cruise missiles powered by high-speed, air-breathing engines, or ‘scramjets’ after acquiring their target.
Scramjets are air-breathing engines capable of sustaining combustion at supersonic speeds without using any moving parts. “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,” DRDO stated.
India has also developed a new, advanced ceramic Thermal Barrier Coating (TBC) with high thermal resistance that can operate beyond steel’s melting point.
India’s test of the hypersonic missile in November 2024 placed it in an elite club of countries comprising the US, Russia, China, and North Korea. The missile test and the scramjet engine test were preceded by China showcasing a new hypersonic glide vehicle, the GDF-600, at its flagship Zhuhai air show.
The tests are the result of many years of research to build a hypersonic missile. The idea had its genesis in 2007 when the Indian Army received the BrahMos Missile system. The then President, Dr. APJ Abdul Kalam, suggested that the Mark-II version of BrahMos should be a hypersonic cruise missile.
India and Russia signed a Memorandum of Understanding in 2009. The BrahMos-2 is intended to be based on hypersonic scramjet technology. Its main purpose is to target deeply buried enemy nuclear bunkers and heavily protected locations.
Scramjet technology is one of the key elements of a hypersonic weapon. Unlike standard subsonic or ramjet engines, a scramjet uses an inlet force in supersonic compressed air before mixing it with hydrogen fuel, thus allowing the engine to achieve Mach 5 speeds and beyond. India began testing scramjet technology in 2016. On August 28, 2016, the ISRO successfully tested two indigenously developed scramjet engines.
To further enhance its scramjet capabilities, India, in 2019 and 2020, tested an indigenously developed hypersonic technology demonstrator vehicle (HSTDV). A scramjet engine powered the HSTDV. While the 2019 test was deemed failed, the 2020 test was successful. During the 2020 test, the scramjet-powered HSTDV flew for about 22-23 seconds at Mach 6 speed.
A ground run for a missile engine is important because it allows engineers to thoroughly test and evaluate its performance before launch, identifying potential issues with functionality, combustion, thrust, and overall health.
Ignition in a scramjet engine is like ‘keeping a candle lit in a hurricane,’ the DRDO said. The DRDO statement said that the scramjet combustor uses a cutting-edge flame stabilization 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.
Catching Up With China – A World Leader In Hypersonic Technology
Globally, the race to get hypersonic weapons is heating up. China is touted as the world leader in hypersonic technology by the US Department of Defense as it surpasses the US and Russia in developing conventional and nuclear-capable hypersonic weapons.
The People’s Liberation Army successfully tested its DF-27 intermediate-range ballistic missile with a hypersonic glide vehicle in 2023, enabling it to effortlessly breach missile defense systems, according to a recent intelligence leak.
The DF-17 HGV-armed medium-range ballistic missile “will transform the PLA’s missile force,” according to the 2023 China Military Power Report. The DF-17 can carry nuclear weapons; however, it is designed for conventional missions.
India’s ambitions are fuelled by the advancement in China’s hypersonic technology.
The US is also playing catch-up. On December 12, 2024, the US Army’s Rapid Capabilities and Critical Technologies Office, along with the US Navy Strategic Systems Programs, conducted a successful end-to-end flight test of a conventional hypersonic missile.
The Long-Range Hypersonic Weapon (LRHW), also known as Dark Eagle, marked 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,” a key aspect of China’s defensive strategy in the Pacific, according to the Congressional Research Service.
Unlike programs in China and Russia, US hypersonic weapons are to be conventionally armed. Because of this, the US Congressional Report titled ‘Hypersonic Weapons: Background and Issues for Congress’ contends that US hypersonic weapons will likely require greater accuracy and be more technically challenging to develop than nuclear-armed Chinese and Russian systems.
Russia loaded its Sarmat intercontinental ballistic missile (ICBM) with nuclear-capable Avangard HGV and was alleged to have used its Zicron hypersonic missile in its ongoing war in Ukraine.
North Korean state media reported a test of the Hwasong 16B hypersonic missile, described by President Kim Jong Un as a “key piece of the nuclear deterrent.”
In this scenario, India’s quest for hypersonic weapons is seen as a move towards diversifying its strategic capabilities. The DRDO has stated that the missile can carry “various payloads,” indicating both conventional and nuclear variants.