by Lt. General Robert Gard, Jr. The Israeli Iron Dome rocket/artillery defense system is touted as destroying 85 to 90 percent of the targets it attacks. U.S. Senator Ron Paul (R-KY) was so intrigued by Iron Dome’s success during a visit to Israel that, upon returning home, he advocated deploying the system in U.S. cities. While few if any other missile defense advocates go that far, several supporters of the U.S. Ground-Based Midcourse national missile defense system (GMD) believe that Iron Dome’s purported success is testimony to the potential effectiveness of GMD. Yet these are two very different systems. Iron Dome, first deployed in 2011, is designed to target small, unguided, inaccurate, slow- and low-flying rockets fired from four to 70 kilometers away from the defensive system. The rockets’ trajectories travel entirely in the atmosphere. An Iron Dome battery consists of an S-Band phased array radar, a fire control element, and three launchers, each armed with 20 explosive-tipped, proximity-fused Tamir interceptors, which are three meters long. GMD faces the far more daunting task of intercepting warheads in space that are delivered by intercontinental ballistic missiles. In the space environment, debris from the booster rocket and countermeasures designed to spoof the defense fly together with, and at the same speed as, the attacking warhead, making it difficult for the interceptor to distinguish between the warhead and non-lethal objects. Impact hit-to-kill vehicles must try to find and collide with warheads traveling 15,000 miles per hour. Iron Dome, known as a low-tiered capability, is one of three systems Israel is developing to provide a layered missile defense complex. The other two have not yet been employed in combat. The Arrow is the top-tiered system, intended to intercept tactical ballistic missiles. Its development was accorded high priority after the first Gulf War, when Iraq attacked Israel with Scud missiles. Arrow II, with an explosive warhead, was first deployed in 2000. Arrow III, which had its second successful flight test in January 2014, is being designed in collaboration with the U.S. Boeing company to employ an impact hit-to-kill interceptor to engage intermediate range ballistic missiles in space. Arrow III, not Iron Dome, is similar to GMD. David’s Sling, also called Magic Wand, is a mid-tier system under development in cooperation U.S. defense contractor Raytheon. It is being designed to intercept high velocity medium and long range rockets, cruise missiles and short range ballistic missiles. It had its first successful intercept test in November 2012, but has not yet been operationally deployed. However successful Iron Dome may be, it cannot serve as a harbinger for the potential of GMD. It is no more a harbinger than a Ford Fiesta is for a Ferrari. They are very different systems.