FIGURE 1. The deployment of the new MC4700 arming, fuzing, and firing system on the W76-1/Mk4A significantly increases the number of hard target kill-capable warheads on US ballistic missile submarines.
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FIGURE 2. Missiles with fixed height-of-burst fuzes can overshoot or undershoot the “lethal volume” (shown here by a gray, dome-shaped line), limiting their ability to destroy hardened targets.
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FIGURE 3. The tilted ellipse in the left upper corner of Figure 3 depicts the spatial distribution of incoming warheads at the time the super-fuze measures its altitude. In this particular case, the orientation of the ellipsoid indicates that the errors leading to a miss at the target are mostly due to a mix of small discrepancies in the velocity and direction of the warheads when they are deployed from the rocket upper stage outside the atmosphere. The orientation and dimensions of this ellipse are well known to a ballistic missile designer, so the altitude measurement can provide information that leads to an estimate of the distance from the lethal volume above the target.
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FIGURE 4. The probability of destroying a fully hardened Russian target with the super-fuzed W76-1/Mk4A warhead atop an American submarine-launched ballistic missile is about 86 percent—far higher than would be the case with the previous fuzing for the warhead.
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FIGURE 5. The likelihood that a submarine-launched ballistic missile will destroy all but the most hardened targets approaches 100 percent.
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FIGURE 6. The first of the new MC4700 AF&F super-fuzes for the W76-1 were completed at the Kansas City Plant in 2007. Delivery of the W76-1/Mk4A warhead to the Navy began in 2009.