Old tech, new threat: Iran’s heat-seeking missiles

In today’s conflicts, aircraft are increasingly vulnerable to ground-based fire—even when facing less advanced militaries or non-state actors. The United States, for example, has reportedly lost dozens of aircraft and drones to Iran during Operation Epic Fury, including an F-15E Strike Eagle shot down in early April, with its crew later rescued.

So how can a country like Iran mount effective air defences against a far more powerful military? Much of the answer lies in anti-aircraft missiles, as an article by National Interest lays out, with technology, though decades old, remains highly effective, widely available, and relatively easy to produce.

Anti-air missile systems generally fall into three main categories:

Infrared (IR) or heat-seeking missiles, which lock onto the heat signature of an aircraft’s engine. A common example is MANPADS—portable, shoulder-fired systems that are relatively cheap and widely used.

Radar-guided missiles, which rely on ground-based or onboard radar to track and intercept targets. These are more complex and harder to manufacture.

Command-guided missiles, which are steered by a human operator during flight. Though they require significant skill, they can be highly effective because they rely on visual tracking and are not defeated by stealth technology.

Modern systems often combine multiple guidance methods, making them more resilient and harder for even advanced aircraft to evade.

Heat-seeking missiles have proven particularly impactful in recent conflicts. They detect infrared radiation emitted by aircraft engines and lock onto the strongest heat source, continuously adjusting their trajectory to follow it.

Why heat-seeking missiles remain so effective

"The missile seeker detects the heat contrast between the engine and the surrounding, relatively cool air. The missile’s seeker locks on to the strongest IR source—most often the aircraft’s engine—and then tracks the heat source, adjusting its flight path continuously. And while early systems relied on relatively simple IR sensors, modern heat-seeking missiles rely on imaging infrared (IR), making it harder for a pilot to trick them with countermeasures such as flares," the outlet explains.

These missiles also use proximity fuzes, meaning they don’t need to directly hit a target—just come close enough to detonate and cause serious damage. Even near misses can be dangerous, as illustrated by reports of a US F-35 by an Iranian heat-seeker in mid-March.

A key advantage is that these weapons are passive: they emit no radar signals. This makes them difficult to detect, often giving pilots little or no warning before impact.

Another reason for their effectiveness is mobility. Many heat-seeking systems are portable and can be deployed quickly from concealed positions.

They are particularly dangerous at low altitudes, putting helicopters, drones, and ground-attack aircraft at high risk. Operators can also use ambush tactics or launch multiple missiles simultaneously, overwhelming defensive systems.

Why production is relatively easy

For countries like Iran, producing these weapons domestically is feasible. The technology matured during the Cold War and has since spread widely. As the article points out, Iran has thousands of Soviet and Russian systems in its arsenal, and can easily reverse-engineer them.

Many systems are modular—made up of components like seekers, propulsion units, and warheads—making them easier to manufacture or reverse-engineer. Crucially, they do not require cutting-edge industrial capabilities such as advanced semiconductor production.

Despite rapid advances in military aviation, relatively simple and cost-effective missile systems continue to pose a serious threat. Their combination of mobility, affordability, and improving technology ensures that even the most advanced air forces must contend with them in modern warfare.

By Nazrin Sadigova