Most interceptors never touch their target. They are not supposed to

In short: Many air defense missiles are built to explode near a threat, not to strike it. A proximity fuze detonates the warhead at the closest point of approach and sprays fragments. Hit-to-kill interceptors do the opposite and need a direct impact. Each design suits a different kind of target.

Watch footage of an interception and the instinct is to look for a bullet hitting a bullet. That picture is accurate for some systems. For many others, a perfect direct hit would be a lucky bonus. The weapon was designed to miss by a few meters and still win.

Read also: Hypersonic speed is not what makes these missiles hard to stop · Stealth aircraft are not invisible. They shrink the radar's horizon. · Air defense rarely misses. It mistakes whose aircraft it is looking at.

A radio trick from 1943

The idea is older than radar screens in fighter cockpits. During the Second World War, American and British engineers fitted artillery shells with a tiny radio transmitter that sensed reflected signals from a nearby aircraft. When the echo grew strong enough, the shell burst. The US Navy first used these proximity fuzes in combat in January 1943, when the cruiser USS Helena shot down a Japanese aircraft in the Pacific.

The gain was simple arithmetic. A timed shell had to burst at the right second. A proximity shell only had to pass close by. Hit rates against aircraft rose sharply, and the same principle later moved into missiles.

Fragments versus impact

Modern interceptors split into two camps. Some carry a blast-fragmentation warhead and a fuze that measures distance with radar or laser. Others carry no explosive at all and destroy the target with kinetic energy.

The split is not random. A ballistic warhead falls fast and is built tough. Fragments may damage its casing without stopping the explosive inside from reaching the ground. Smashing it head-on at several kilometers per second leaves far less to chance. An unguided rocket or a slow drone is softer, and a fragment cloud covers small guidance errors.

What can go wrong

• Early detonation: clutter, terrain or rain can trigger a fuze that is too sensitive.
• Late detonation: against very fast targets, the fragments may arrive after the threat has already passed.
• Partial kill: the target breaks up but heavy pieces, sometimes the warhead itself, keep falling.
• Debris: even a clean intercept drops shrapnel over a wide area, which is why shelter rules stay in force.

The engineering challenge is timing. Two objects closing at combined speeds above Mach 5 spend only a few milliseconds inside the lethal radius. Fuze designers tune the burst so the fragment cone points where the target will be, not where it was. This is also why hypersonic speed on its own is a weaker shield than maneuvering.

Why a country needs both

No single kill method covers every threat. Cheap fragment interceptors handle large salvos of rockets, while costly kinetic ones are saved for ballistic missiles. That division is the core logic behind the idea that layers defend a country, not one missile. Both camps also depend on the same front end: a fire-control radar that is deleting almost everything else so the interceptor gets a clean track.

The history and the physics are covered well in the Wikipedia article on the proximity fuze.

Next time interception video shows a flash a short distance from the target, do not count it as a miss. Check what the interceptor was built to do first.