Decoy

A decoy is a false target designed to deceive the enemy, drawing fire away from the real thing, wasting expensive weapons on worthless objects, and confusing the enemy's picture of what is where. Decoys run from crude inflatable tanks to sophisticated electronic devices that mimic an aircraft's radar signature, and they all exploit the same fundamental leverage: it is almost always cheaper to build a convincing fake than to build the real thing, so a decoy that draws an expensive weapon or a costly reconnaissance effort has already won its exchange, even if it is destroyed in the process, because the enemy spent far more than the decoy cost.

The economics that make decoys powerful

The strategic appeal of decoys is arithmetic. A missile costs far more than the decoy that seduces it, a reconnaissance sortie costs far more than the fake target it wastes its time photographing, and a strike planned against a decoy is a strike not delivered against something real, so decoys impose disproportionate cost and waste on an enemy for very little outlay. This logic has run through warfare for a long time, the Allied deception before D-Day used dummy tanks, landing craft, and even a fictional army to convince Germany the invasion would come at Calais, tying down real German forces to defend against a threat that did not exist, one of the most consequential deceptions in history, achieved substantially with decoys and the fake radio traffic to sell them. The same principle drives modern practice, and Ukraine turned it into a running success story, deploying decoy HIMARS launchers and other fake systems good enough that Russia expended real missiles destroying them, wooden and inflatable targets absorbing strikes worth hundreds of thousands of dollars each, an exchange so favorable it became a deliberate strategy.

The forms decoys take

Decoys span every domain and sensor. There are physical decoys, inflatable or constructed fakes of tanks, aircraft, and launchers, sometimes rigged with heat sources to fool thermal sensors, so they look real not just to eyes but to the infrared and radar systems that now do most of the seeing. There are expendable decoys launched from platforms under attack, the towed radar decoys that lure a missile away from an aircraft, the naval decoys that seduce an anti-ship missile off the ship, closely related to countermeasures like chaff and flares. There are electronic decoys that generate false radar returns or mimic the emissions of real systems, creating phantom aircraft or ships on an enemy's screens. And at the strategic level, ballistic-missile warheads deploy decoys in space, cheap balloons and objects that fall alongside the real warhead and look identical to a defending sensor, which is precisely the problem that makes midcourse missile defense so hard, because the defender cannot tell the lethal object from the decoys traveling with it. Across all these forms, the decoy's job is the same, to make the enemy waste effort, weapons, and attention on something that does not matter, while the real target survives.

Why don't better sensors just defeat decoys?

Because decoys evolve to match the sensors, and the contest never ends. As sensors improve, adding thermal imaging, radar, multiple wavelengths, decoys improve too, gaining heat sources, radar reflectors, and more convincing signatures, so a decoy that fools a modern multispectral sensor is simply more elaborate than one built to fool the naked eye, not fundamentally different in purpose. The economics still favor the decoy, because it remains cheaper to fake a signature than to build a real system, and because the defender or attacker must treat every plausible target as potentially real, which means even an imperfect decoy that might be real still imposes cost and hesitation. This is the same measure-countermeasure spiral that runs through all of warfare, and as long as it is cheaper to deceive a sensor than to build the real thing it is looking for, decoys will keep earning their place.