India has taken another decisive step in hypersonic weapons development with the successful ground test of an active-cooled, scramjet subscale combustor.
The test was conducted in late April 2025 at a newly commissioned scramjet facility in Hyderabad by the Defence Research and Development Laboratory (DRDL), part of the nation’s Defence Research and Development Organisation (DRDO). The evaluation demonstrated sustained supersonic combustion, validating the scramjet component’s design and providing a foundation for full-scale, flight-ready trials, India’s Defence Ministry stated.
“For the first time, DRDO has successfully tested a scramjet combustor with active cooling for a full 1,000 seconds,” Vijainder K. Thakur, a defense analyst and retired Indian Air Force fighter pilot, told FORUM. “This marks a major milestone, demonstrating India’s ability to engineer scramjet systems that can operate continuously for several minutes rather than just brief bursts.”
Hypersonic cruise missiles are propelled by scramjets at five times the speed of sound, or Mach 5, which is about 6,100 kilometers per hour. Such weapons present challenges for conventional missile defense systems. Their high speeds, maneuverability and low-altitude flight paths make them difficult to track and intercept using traditional radar systems.
Nations including Australia, China, Russia, South Korea and the United States also are developing hypersonic capabilities.
In March 2025, the U.S. Defense Department conducted a second successful flight of a fully recoverable uncrewed hypersonic test vehicle. The aircraft-launched c, powered by a liquid-fuel rocket engine, exceeded Mach 5 over the Pacific Ocean before landing at Vandenberg Space Force Base, California, the Defense Department stated.
India is bolstering its defense capabilities amid concerns over China’s attempts to gain influence in the Indian Ocean region, while the nations’ decades-long border dispute has sparked deadly clashes in the Himalayas.
The scramjet test addressed propulsion and thermal management challenges associated with high-velocity systems, including through innovations in thermal barrier coatings and fuel that absorbs heat to regulate engine temperature before combustion.
Such advancements reflect the maturation of India’s hypersonic capabilities, first showcased with the 2020 flight test of the Hypersonic Technology Demonstrator Vehicle, which conducted 20 seconds of sustained Mach 6 flight, about 7,400 kilometers per hour, using a scramjet engine.
“The primary obstacle to building a functional hypersonic cruise missile isn’t the scramjet engine itself — it’s managing the extreme heat over time,” Thakur said. “What makes DRDL’s breakthrough particularly noteworthy is their solution to the intense heat generated by friction: a combination of active cooling and advanced thermal barrier coatings.”
Active cooling involves circulating kerosene-based fuel through channels in the engine’s combustor walls to absorb and manage the extreme heat generated during hypersonic flight. Once heated, the fuel enters the combustion chamber, where it ignites more efficiently, improving cooling and combustion performance.
Equally critical to the test’s success was the application of a next-generation ceramic thermal barrier coating developed by the DRDL and the Department of Science and Technology, Thakur said. The coating shields components from the searing temperatures — up to 2,500 degrees Celsius — inside the combustor, thereby extending engine life and reliability.
Development of specialized fuel by the DRDL and local firms also “represents a major advancement,” Thakur said. “It not only helps in cooling the engine but also reduces reliance on imported technology.”
The DRDO scramjet eventually could replace imported technology on weapons platforms, he said. “This achievement opens the door for India to field a fully indigenous hypersonic cruise missile in the near future.”
