L3Harris Takes Its Solid-Fuel Ramjet to Full-Scale Testing

L3Harris has begun full-scale testing of a solid-fueled ramjet propulsion system. The company is aiming to build the propulsion foundation for a family of multi-mission missiles around a new fuel chemistry.

The test campaign

Work is running at the company’s facility in Orange County, Virginia. Tests demonstrated booster and SFRJ performance aligned with expectations. The effort is internally funded, with additional ground tests planned later in 2026.

Scott Alexander, president of Propulsion Systems, Missile Solutions, said the team “continues to push the boundaries of ramjet propulsion through disciplined testing and new fuel chemistry.”

How a solid-fueled ramjet works

A ramjet is an air-breathing engine with no moving parts. In place of a compressor stage it relies on incoming air being compressed by inlet geometry at high speed. That is why a ramjet cannot start from rest: the missile must first be accelerated by a booster rocket to the speed at which the cycle works.

In the solid-fueled variant the fuel sits inside the motor as a solid grain. Tanks, pumps and flow-control hardware needed for liquid-fueled ramjets disappear. The result is simpler, cheaper and easier to store — at the cost of the ability to throttle thrust in flight.

Why propulsion sets the ceiling

Range is a direct consequence of propulsion. A conventional solid rocket motor carries its oxidiser as well as its fuel, and that mass fixes the upper bound on range. A ramjet takes oxidiser from the atmosphere, so the same launch weight travels far further.

The second gain is terminal energy. A rocket motor burns out in the first seconds and coasts the rest of the way; a ramjet keeps producing thrust throughout flight. The missile arrives fast and still able to manoeuvre. In air-to-air engagements that difference decides whether a target performing an evasive turn can be caught at all.

The familiar example is the European Meteor air-to-air missile, whose defining characteristic is that it is still under power at the far end of its envelope — which is what produces its unusually large no-escape zone.

The scaling problem

Ramjet propulsion is not new; it has appeared in missiles and target drones since the 1950s. What has kept it from spreading is production economics rather than physics. Combustion chamber materials, inlet geometry and the internal design that makes a fuel grain burn evenly all demand repeatable quality at volume.

That is why ramjet-powered missiles have generally stayed in the premium segment, built in small numbers. The target implied by the L3Harris announcement is to bring the technology down into the mid-price band.

Cost is the headline

The notable part of the announcement is not the performance claim but the cost framing. The company describes the design as high-energy and lower-cost, and talks about modular solutions deployable from existing platforms and scalable for mass.

That framing sits at the centre of the current US procurement debate. Pacific wargaming has repeatedly indicated that long-range munition stocks could be exhausted in the opening weeks of a conflict. The problem is not the performance of any single round but how many rounds of that performance can be bought. Pairing a ramjet’s range with a producible unit cost is aimed squarely at that equation.

Where it could go

The company points to a multi-mission missile family, long-range manoeuvring interceptor development, and strike munition programmes. The interceptor line is the most telling: in air defense, ramjet propulsion supplies the energy needed to meet a target at high altitude and long range rather than running out of speed on the way.

The wider read

Ramjet and air-breathing propulsion is an area where Turkish industry has taken concrete steps. ROKETSAN’s long-range air defense and cruise missile work has involved research into alternative propulsion architectures, and TÜBİTAK SAGE and TUSAŞ Engine Industries are working the same ground.

The gating problem in this field is materials and fuel chemistry. A ramjet combustion chamber is exposed to high temperature for far longer than a rocket motor, which makes heat-resistant composites and ceramics a prerequisite rather than an optimisation. That L3Harris chose to foreground new fuel chemistry in its announcement points at the same threshold — and Turkey’s existing base in composite and energetic materials is where that work has to start.