Hemlock, the long-range strike missile

Why this missile is needed

India's heavy strike weapons are already in serial production: BrahMos and Pralay are built at an officially stated 100–200 rounds a year, and that capacity is still growing. They are the right weapons for hardened, high-value and time-critical targets, but at ₹25–35 crore a round they are too valuable to spend on the much longer list of ordinary targets a campaign has to hit. There is nothing below them that can be used in that quantity and replaced. The missing-middle doctrine describes this gap: India needs cruise missiles cheap enough to fire in salvos that wear down air defences, clearing the way for crewed aircraft and heavier weapons.

Hemlock is built for that gap. It carries a 450–500 kg warhead 1,000–1,500 km at ₹3–5 crore, with a target rate of 20–40 rounds a month — similar reach and payload to a Tomahawk at a far lower unit cost. Nightshade set up the way of working: the test routine and the Indian supplier base. Hemlock uses all of that in a weapon built for long range from the start, with its own airframe, its own guidance and navigation, and room for a 450–500 kg warhead.

Specification

The missile is one airframe, one engine, and one navigation stack: a composite body and a booster that launches it from a container. Everything is sized around the GTRE Manik 450 kgf expendable turbofan, for 1,000–1,500 km of low-level flight. It is not a stealth missile; it survives by flying low, under the radar horizon, and by arriving in numbers.

High-altitude engine operation

Launching from high plateaus decides the engine size. At 4,500 m the air is about 63% as dense as at sea level, and a turbofan loses thrust as the air thins. GTRE has not published an altitude thrust curve for the Manik, so the figure here is estimated from the released sea-level rating: roughly 2.6–2.9 kN at 4,500 m and Mach 0.75, about 60–65% of the rating. The missile needs about 220 kgf of that to hold level cruise at ~1,300 kg. What is left — 45 to 75 kgf, or 20 to 35% — is the reserve that pays for climbing out of a valley, banking hard, and the steep final dive. A missile with no reserve can cruise, but it cannot manoeuvre.

This comes from published requirements: launch from at least 4,500 m (HQ IDS TPCR 2025, item 15), a 5,000 m ceiling, and −30 °C to +55 °C (Army questionnaire, Jul 2026 §3). See procurement alignment.

Flying valleys, then diving on the target

Himalayan valleys are narrow, so the missile has to bank hard to follow them, and hardened targets need a steep hit rather than a shallow one. It follows the valley shape below the radar horizon, then pitches into a steep dive, matches the target against stored images, and detonates inside on a delayed fuze.

Five-layer navigation stack

Five layers of navigation. Each one takes over when the layer above it fails, and none is asked to do more than it can.

How a mission runs: open map data (Copernicus GLO-30, Sentinel-2) → pre-flight preparation (sun-angle shading, terrain hashing, route storage) → in-flight matching (downward camera, onboard compute, position fixes every 20–60 km) → terminal lock. It needs no classified data and no spy satellites.

Terrain-referenced fixes

The maps are public. NASA's SRTM flight collected the elevation data behind DTED Levels 1 and 2, so mapping secrecy is no longer the issue. What matters now is what the data actually means, how accurate it is, and how much texture the terrain has — not getting hold of it.

• Short-burst TERCOM. The altimeter stays off most of the way and only switches on briefly at planned points: a burst of under a second against stored terrain strips, then back to silence.
• Beam-width limit. A normal altimeter reads the nearest point in its beam, not straight down. Accurate terrain navigation needs a narrow or interferometric beam, which is why the altimeter arrives in phases (Section 06).

Fielded precedents

Scene matching

Midcourse and final fixes use classic DSMAC: a camera image is matched against a stored reference to get an exact position, without emitting anything. The reference has to match the conditions of the strike — same season, same time of day — and flat, bare terrain is the hardest case.

Altimeter supply chain and the phased plan

Altimeters fall under MTCR export controls, and Western suppliers cannot be counted on for a cruise missile. So the plan has three steps: a commercial off-the-shelf sensor for development work, an Indian FMCW/LPI altimeter for production, and a licensed second source as backup.

Domestic supply base

The missile is designed around suppliers that already exist: a government-designed engine built by private precision firms, shared avionics and navigation electronics, and structures made with India's car-industry and precision-machining base instead of scarce aerospace autoclaves.

• Engines. Hemlock flies the GTRE Manik 450 kgf twin-spool turbofan, built by BrahMos Aerospace Thiruvananthapuram (BATL). Deliveries are still at low rate — 15 of a first order of 35 engines by mid-2025 — and the Kerala plant and its private suppliers are being scaled up toward what the LRLACM and Hemlock programmes need together.
• Actuation. Brushless DC servo actuators adapted from car-industry steer-by-wire suppliers, rated for one flight.
• Structure. Skins made by resin transfer moulding (no autoclave needed), with thicker composite and 7075-T6 aluminium ring frames around the payload and engine bays.

Alignment with published requirements

Hemlock fits the tri-service LRLACM requirement:

Why it costs what it costs

• Target: ₹3–5 Cr at 20–40 rounds a month.
• Most of the saving comes from navigation, not the airframe. Older cruise missiles spend about a quarter of their cost on custom TERCOM/DSMAC hardware; Hemlock replaces that with standard compute, open maps, a mid-cost CRPA, and classic DSMAC.
• The engine decides the price: the Manik 450 has to come down from prototype pricing to ₹1.1–1.4 Cr per unit at rate.
• For reference: ₹4 Cr is about $450k — between Ukraine's Flamingo (under $600k) and the US FAMM average of $450k, and roughly a fifth of a Tomahawk. Early low-rate builds will cost clearly more than the at-rate target; volume, not redesign, is what brings cost down.

Salvo maths and the cost-per-kg·km comparison with missiles in service are on the trajectory page.

Development plan and test qualification

Testing on a budget

Flight hours cost the most, so each part is proven in the cheapest place that can still prove it wrong, and only flown after that — cheapest lesson first.

Still open: Manik engine rate — BATL delivers at low rate today, against 240–480 a year needed at full speed. Tracked on the supply-chain gap list.

Where to go next