Key Points
- DRDO scramjet combustor ran for 1,200 seconds, up from 700 seconds in January
- Test conducted at Scramjet Connect Pipe Test Facility in Hyderabad on 9 May
- Engine uses indigenous liquid hydrocarbon endothermic fuel technology
The Defence Research and Development Organisation (DRDO) conducted a 1,200-second ground test of an actively cooled scramjet combustor on Saturday, marking a significant advance in India’s hypersonic cruise missile development programme.
The test at the Scramjet Connect Pipe Test Facility in Hyderabad nearly doubled the run time achieved in January this year, when the same combustor ran for over 700 seconds.
A scramjet — short for supersonic combustion ramjet — is an air-breathing engine that operates at hypersonic speeds, typically above Mach 5 or five times the speed of sound, by compressing incoming air without moving parts.
The Defence Research and Development Laboratory (DRDL), a DRDO unit, designed the combustor, which was manufactured by industry partners.
The engine uses liquid hydrocarbon endothermic fuel developed in India — a fuel type that absorbs heat as it breaks down, allowing it to cool the engine while simultaneously powering combustion.
How active cooling enables sustained hypersonic flight
At hypersonic speeds, air friction generates extreme temperatures that can exceed 2,000 degrees Celsius. The actively cooled combustor addresses this by circulating fuel through channels in the engine walls before combustion.
The fuel absorbs heat from the structure, keeping temperatures within survivable limits for the engine materials.
The combustor also uses high-temperature thermal barrier coatings — ceramic layers applied to metal surfaces that insulate the underlying structure from direct heat exposure.
These coatings, combined with the active cooling system, allowed the engine to sustain operation for 20 minutes during the ground test.
Hypersonic cruise missiles travel at sustained speeds above Mach 5 while manoeuvring in the atmosphere, making them difficult to intercept with conventional air defence systems.
The technology is being pursued by the United States, China and Russia, with India now demonstrating extended-duration scramjet capability.
Programme moves toward flight testing
The ground tests validate both the combustor design and the Scramjet Connect Pipe Test facility’s ability to simulate hypersonic flight conditions. Defence Minister Rajnath Singh described the test as a foundation for the hypersonic cruise missile development programme.
By the numbers
- 1,200 seconds
- May 2026 scramjet combustor test duration
- 700 seconds
- January 2026 scramjet combustor test duration
- Mach 5
- Minimum speed threshold for hypersonic classification
Samir V Kamat, secretary, Department of Defence Research and Development and chairman of DRDO, confirmed the test results. The January and May tests together demonstrate increasing confidence in the scramjet design’s thermal management systems ahead of eventual flight trials.
Your Questions, Answered
What is a scramjet combustor?
A scramjet is a supersonic combustion ramjet — an air-breathing engine that operates at hypersonic speeds above Mach 5 by compressing incoming air without moving parts. The combustor is the chamber where fuel mixes with compressed air and ignites.
Why is active cooling important for hypersonic missiles?
At hypersonic speeds, air friction generates temperatures exceeding 2,000 degrees Celsius. Active cooling circulates fuel through engine walls to absorb heat before combustion, keeping temperatures within limits the engine materials can survive.
How does this test compare to the January 2026 test?
The May test ran for over 1,200 seconds, nearly doubling the 700-second run time achieved in January 2026. Both tests were conducted at the same Scramjet Connect Pipe Test facility in Hyderabad.
Which countries are developing hypersonic cruise missiles?
The United States, China and Russia are actively developing hypersonic cruise missile technology. India's extended-duration scramjet tests demonstrate it is advancing similar capabilities for its defence programme.
