India’s Extended Trajectory-Long Duration Hypersonic Cruise Missile (ET-LDHCM) project, spearheaded by the Defence Research and Development Organisation (DRDO) under the classified Project Vishnu, marked a major technological milestone in 2024.

The DRDO successfully finalised the design of an active-cooled scramjet engine, the core propulsion technology enabling sustained hypersonic flight at speeds around Mach 8 (approximately 11,000 km/h). 

This achievement included a critical 60-second sub-scale combustor test that validated the missile’s hypersonic combustion process under extreme conditions.​

The scramjet engine represents a revolutionary air-breathing propulsion system that draws oxygen from the atmosphere instead of carrying onboard oxidisers, greatly enhancing fuel efficiency and enabling longer flight duration.

This propulsion breakthrough empowers the ET-LDHCM to maintain hypersonic speeds deep into enemy territory with high precision and mid-course manoeuvrability. The system is designed to withstand temperatures above 2,000°C through advanced heat-resistant and oxidation-resistant materials, critical for hypersonic operation at low altitudes to evade enemy radar detection and interception.​

The ET-LDHCM missile is being developed indigenously, in alignment with India’s Atmanirbhar Bharat policy, making use of domestic technologies and collaborations with private defence contractors and SMEs.

It offers a maximum range estimated at 1,500 km and a payload capacity between 1,000 to 2,000 kg, adaptable for either conventional or nuclear warheads. The missile’s versatility extends to multiple launch platforms, including land-based launchers, aircraft, and naval vessels, expanding India’s tactical and strategic strike capabilities.​

This successful scramjet combustion test marked a critical step transitioning from technology demonstration toward a fully operational hypersonic cruise missile system. However, the program awaits official funding approval from India’s Ministry of Defence to proceed with full-scale missile fabrication, integration, and flight trials.

Preparations for eventual flight tests are underway, with integration jigs and other infrastructure being readied.

Once inducted, the ET-LDHCM is set to significantly enhance India’s strategic deterrence and position the country among a select group of nations possessing advanced hypersonic strike technology, including the US, Russia, and China.​

2024 witnessed a breakthrough in India’s hypersonic missile development with the ET-LDHCM project achieving critical validation of its scramjet engine technology and hypersonic combustion. These developments reflect rapid maturation of next-generation hypersonic technologies, propelling India towards operationalising a Mach 8-class long-range cruise missile by the end of this decade.​

This long-duration hypersonic cruise missile project represents a leap in India’s aerospace and defence capabilities, combining precision strike, extended range, advanced propulsion, and survivability in a single weapon system crucial for future strategic balance in the region.

IDN (With Agency Inputs)