Israel claims that of the purported 3,500 rockets fired from Gaza during its latest military operation, 90 percent of those that would have hit population centres were neutralised by the Iron Dome system. But experts outside of the country have questioned the efficiency of the system. "'In order for Iron Dome to have any chance of detonating the rocket warheads, it must engage from the front, in what is called an Inverse Trajectory," wrote Richard Lloyd, a warhead designer, in a recently declassified 28-page technical report.
In other words, the Iron Dome missiles must approach rockets head-on, or the probability of intercepting them drops to virtually zero. This is due to the nature of the interceptors' warhead, which is not in the nose of the missile but a third of the length down. When very close to its target, the interceptor will detonate, sending a shower of steel rods out to the side of the missile to destroy the rocket. The only way these rods can successfully hit a rocket warhead is when the interceptor comes up to meet the rocket and passes just by it. Attempting to hit the rocket side-on will have virtually no chance of success.
Theodore Postol, a professor at the Massachusetts Institute of Technology (MIT) and missile defence expert, headed a group that assessed the effectiveness of the Patriot missile defence system installed in Israel at the end of the first Gulf War. While figures at the time reported a resounding success - Postol told Al Jazeera that although officials claimed that 94 percent of Scud and al-Hussein missiles were shot down - he estimates the real figure was "probably zero".
Postol, a vocal critic of the Iron Dome, has based a portion of his research on open source pictures and video of the Iron Dome's Tamim interceptor contrails, the visible smoke path left by a missile. He told Al Jazeera that these showed "that 80-90 percent of the time, the Iron Dome [missiles] are not even close to the correct engagement geometry", and added that the Iron Dome system is not engaging rockets head-on and therefore not working as it should.
"There is no way that a smartphone camera could distinguish between a double and a single explosion," Shapir wrote.
But Lloyd argued that even when the rockets are being intercepted, they aren't necessarily being neutralised. The warheads contained in Palestinian rockets are "very difficult to detonate because they are made with thick steel cases... backed with insensitive TNT explosive", he found.