India’s Long-Term Extended Trajectory All current regional air and missile defense architectures are surpassed by the Hypersonic Cruise Missile (ET-LDHCM), the first indigenous weapon capable of maintaining Mach8 flight for over 1,000 kilometers, carrying a 2,000 kg nuclear or conventional payload, and maneuvering along its trajectory.
Under DRDO’s classified Project Vishnu, the system transforms crisis-stability calculations in comparison to China and Pakistan, places India in the exclusive club of states with operational hypersonic strike reach, and heralds the arrival of an Indian industrial base capable of designing, constructing, and maintaining ultra-high-speed propulsion technologies.
The technical, industrial, doctrinal, and geopolitical aspects of ET-LDHCM are all examined in detail in the report that follows. It also compares ET-LDHCM to peer hypersonic systems overseas, legacy Indian missiles, and the interception capabilities of cutting-edge air defense networks like S-400, S-500, HQ-19, and Iron Dome.
Hypersonic weapons can move erratically within the atmosphere while traveling at speeds greater than Mach 5 (6,173 km/h). There are two main architectures that are prevalent:
vehicles that ride a ballistic booster and then skip-glide to their target are known as boost-glide vehicles (BGVs);
Hypersonic cruise missiles (HCMs) that breathe air and are propelled by scramjets for the majority of their flight.
Based on a scramjet that was tested to 1,000s endurance in November 2024, ET-LDHCM is a member of the latter class. It reduces defender reaction times to less than 60 seconds for a 1,000km shot by combining radar-horizon concealment with dynamic course corrections while staying within denser layers of the atmosphere at altitudes of 15–30km.
According to DRDO’s 2025 cost sheet, Project Vishnu reduces foreign content below 12% by integrating more than 135 Indian MSMEs that supply high-entropy alloys, carbon-carbon composites, and ceramic matrix coatings.
On November 12, 2024, during a ground run at DRDL’s hypersonic facility, the kerosene-fired scramjet produced net thrust 22% higher than BrahMos ramjet benchmarks while maintaining combustion for 1,000s at inlet Mach2.5 and exit Mach8. By using atmospheric oxygen to remove oxidizer mass, propellant weight was reduced by 44%, allowing for a larger warhead or greater range within the 14-meter airframe.
A2/AD Penetration: The missile’s flight profile allows for deep-strike options against logistic hubs at Golmud within 6-7 minutes from Leh valley TELs by avoiding static S-400/500 arrays surrounding PLA Rocket Force bases in Tibet and Xinjiang.
Carrier Deterrence: The Su-30MKI’s air-launched ET-LDHCM compresses the Chinese task-force reaction time to less than 90 seconds by creating a 1,500 km anti-ship bubble that covers PLAN carrier egress lanes in the South China Sea.
Jodhpur to Pindi GHQ flight times drop to less than 180 seconds, severely impairing decision-loops intended for 8–10 minute Agni arrivals.
A cross-range weaving Mach8 HCM that shows up on radar within 70 kilometers is too strong for Pakistan’s current HQ-9B (Mach6 intercept).
Early hedging behavior to restore deterrence is demonstrated by Islamabad’s alleged interest in Chinese HQ-19 and DF-17.
ET-LDHCM challenges India’s No-First-Use pledge by introducing a “disarming first-strike” temptation in the event that adversaries’ early warning systems fail. To prevent miscalculation, it is advised to implement permissive action links, pre-delegation locks, and confidence-building notification regimes similar to the India-Pakistan ballistic-missile pre-test pact.
By 2032, DRDO intends to have a 1.2GW solid-fuel ducted ramjet (SFDR) developed for a Mach10,2,500km next-generation model.
The new Uttam L-band phased array network will serve as the radar cue for India’s Project Akash-TEJAS (A-T), which aims to develop a hit-to-kill Exo-Endo interceptor with a closing speed of 5 km/s.
Even the most sophisticated layered air defense systems currently in use are rendered ineffective by the ET-LDHCM’s combination of scramjet propulsion, maneuverability, and platform agnosticism, which reduces adversary response times to single-digit seconds.
In addition to being a technological achievement, it signifies a significant change in Asia’s strategic thinking and the development of a domestic innovation ecosystem. For the next 25 years, the stability of the region will be determined by how its neighbors adjust, whether through accelerated arms races, cooperative security frameworks, or arms-control initiatives.
