If geopolitical events call for securing nuclear facilities in an unraveling North Korea or Iran, the Zumwalt is the Navy's surest way to arrive unannounced. From the shallows, the Zumwalt can then wipe out enemy defenses up to 72 miles away. Sailors don't cram shells into the dual 155-millimeter guns nor do they clear the casings. The guns are controlled—point, click, boom—by a computer in the command center; they fire GPS-guided shells, considered by the Navy to be more like rockets than artillery because of their ability to adjust trajectory in flight. The ship also carries a battery of SM-2 antiaircraft missiles, surface-targeting Tomahawks, missile-destroying ESSM interceptors, and vertically launched ASROC antisubmarine torpedoes, all distributed among 80 missile cells that line the Zumwalt's hull. The location of the cells ensures that the missiles can't all be disabled by a single enemy strike and serves as an extra layer of defense around the ship.