A high-quality inertial guidance system is capable of placing a reentry vehicle within a few hundred feet of the target after a flight of over 6,000 miles. However, this is still accurate enough to inflict massive casualties if the missile is armed with a weapon of mass destruction. As more modern guidance system technology is proliferated, countries will be able to improve the accuracy and lethality of their missile forces. Many ballistic missiles carry penetration aids to improve the chances of a reentry vehicle penetrating a ballistic missile defense system. Penetration aids are devices that attempt to deceive or jam sensors used to detect and track missiles and RVs.
Penetration aids are of increasing importance to countries operating ballistic missiles.