Warhead
The Javelin missile’s tandem warhead is a high-explosive antitank round. This round utilizes an explosive shaped charge to create a jet of superplasticity deformed metal formed from trumpet-shaped metallic liners. The result is a high velocity jet that can penetrate armor.
The Javelin counters the advent of explosive reactive armor (ERA). ERA panels lie over a vehicle’s main armor and explode when impacted by a warhead. This explosion does not harm the vehicle’s main armor, but causes steel panels to fly into the path of the antitank round’s jet, so that the jet expends its most potent energy cutting through the panels, rather than through the main armor.
The Javelin uses two shaped-charge warheads in tandem. The precursor charge sets off the ERA and clears it from the path of the main charge, which then penetrates the target’s primary armor.
A two-layered molybdenum liner is used for the precursor and a copper liner for the main charge.
To protect the main charge from the explosive blast, shock, and debris caused by the impact of the missile's nose and the detonation of the precursor charge, a blast shield is used between the main and precursor charge. This was the first composite material blast shield and the first that had a hole through the middle to provide a jet that is less spread out.
A newer main charge liner produces a higher velocity jet. This change makes the warhead more effective as a penetrator and smaller, with more room for propellant to increase the missile's range.
Electronic arming and fusing, called Electronic Safe Arming and Fire (ESAF), is used. The ESAF system enables the firing and arming process to proceed, while imposing a series of safety checks on the missile. ESAF cues the launch motor after the trigger is pulled. When the missile reaches a key acceleration point (indicating that it has cleared the launch tube), the ESAF initiates a second arming signal to fire the flight motor.
After another check on missile conditions (target lock check), ESAF initiates final arming to enable the warheads for detonation upon target impact. When the missile strikes the target, ESAF enables the tandem warhead function (provide appropriate time between the detonation of the precursor charge and the detonation of the main charge).
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