New propulsion program for legacy missile delivers a sharper sting

REDSTONE ARSENAL, Ala. (May 21, 2025) – The FIM-92 Stinger has long been one of the U.S. Army’s most versatile missiles.

In service since 1981, it can operate both surface-to-air and air-to-air and travel at speeds up to Mach 2. Stinger’s effective range, or distance, has not changed much over the years. A key limiting factor is the propulsion technology it uses. It is powered by a traditional solid fuel rocket motor -- a self-contained propulsion system that doesn't require external air or additional fuel sources.

Enter “Red Wasp” – its moniker a homage to the legacy system.

Red Wasp is an air defense interceptor science and technology program at the U.S. Army Combat Capabilities Development Command Aviation & Missile Center utilizing advanced propulsion technology. Initially conceptualized in 2022, the Air and Missile Defense Capability Area in DEVCOM AvMC’s Technology Development Directorate selected the Stinger form factor as a worthy candidate to apply solid fuel ramjet technology to dramatically increase its potential effective distance.

“When we first explored the concept, several industry propulsion experts expressed concerns about the feasibility of applying solid fuel ramjet technology to the Stinger form factor,” said Capability Area Lead for Air and Missile Defense John Gibbs. “The team took that as a challenge and within 18 months, successfully demonstrated the concept in a flight test.”

Integral rocket solid-fueled ramjet is a dual propulsion cycle that uses a conventional solid rocket motor to initially boost the missile up to supersonic speeds. When the booster burns out, a port opens at the front end of the rocket motor allowing air to enter the combustion chamber and ignite the ramjet fuel. The advantage when operating in a ramjet cycle is that the primary oxidizer, air, does not need to be carried on board. The ramjet cycle thus greatly increases the engine’s delivered performance and ultimately the missile’s range.

Red Wasp is an example of a high risk, high reward type of program – and one that is 100% government-owned, said Deputy Capability Area Lead for Air and Missile Defense Chappell Ray.

It also points to the hands-on engineering happening at the Center every day – engineering that when handled in-house, can accelerate a program’s technology readiness level.

After a successful test at Dugway Proving Ground in 2024 the AvMC team has continued exploring optimization of Red Wasp in preparation for transition into a larger S&T project.

“We will fly some more in July,” said Red Wasp Principal Investigator Dr. Brian McDonald. “We'll have a few different ramjet fuels, looking at the delivered performance of several different formulations, and we'll have some different insulators in them. The idea is to take six motors out there, each with a little bit of variance from what we had in May 2024 and see what we get in an actual flight test.”

While Red Wasp is classified under applied research that is exclusively conducted by government propulsion subject matter experts, the team does expect to expand the project to encompass industry partners.

“We are looking at just the propulsion with this effort. The greater goal is to work with outside partners to integrate a full air defense interceptor, while DEVCOM AvMC engineers continue to mature our in-house design to further develop technologies that may benefit industry concepts.” Ray said.

With the U.S. Army’s efforts to modernize its acquisition process – Red Wasp delivers on that mandate to be both faster and cheaper while keeping paramount the number one goal: equipping the Warfighter with overmatch capabilities.

“Red Wasp will enable soldiers to engage Short Range Air Defense, or SHORAD, threats such as unmanned aerial systems with Intelligence, Surveillance and Reconnaissance, or ISR, capabilities at much longer ranges. Denying adversarial UAS with ISR packages the ability to target us increases our survivability,” Gibbs said. “As ISR sensor technology improves, the effective range of enemy targeting could challenge the range capability of existing SHORAD interceptors.”

“So, with Red Wasp, we can reach out and touch them at greater distances.”

After a successful technology transition, this design will be scaled up for other Army applications.

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The U.S. Army Combat Capabilities Development Command, known as DEVCOM, is Army Futures Command’s leader and integrator within a global ecosystem of scientific exploration and technological innovation. DEVCOM expertise spans eight major competency areas to provide integrated research, development, analysis and engineering support to the Army and DOD. From rockets to robots, drones to dozers, and aviation to artillery – DEVCOM innovation is at the core of the combat capabilities American Warfighters need to win on the battlefield of the future. For more information, visit devcom.army.mil/.