Air Defense: Iron Dome Works

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July 20, 2009: Israel had the first successful test of its Iron Dome anti-rocket system on July 15th. The system detected and shot down several BM-21 rockets. The Israelis expect to have the system in action, along the Gaza border, later this year. The manufacturer, Rafael, was offered a large bonus if they got the system working ahead of schedule. When Iron Dome was first proposed three years ago, it was to take five years (until 2012) to get it operational. In addition to the cash incentive, there's also the rockets still coming out of Gaza, and being stockpiled by Hezbollah in southern Lebanon.

Iron Dome uses two radars to quickly calculate the trajectory of the incoming rocket (Palestinian Kassams from Gaza, or Russian and Iranian designs favored by Hezbollah in Lebanon) and do nothing if the rocket trajectory indicates it is going to land in an uninhabited area. But if the computers predict a rocket coming down in an inhabited area, a $40,000 guided missile is fired to intercept the rocket. This makes the system cost-effective. That's because Hezbollah fired 4,000 rockets in 2006, and Palestinian terrorists in Gaza have fired over six thousand Kassam rockets in the past eight years, and the Israelis know where each of them landed. Over 90 percent of these rockets landed in uninhabited areas. Still, a thousand interceptor missiles would cost $40 million. But that would save over a hundred lives, and hundreds of injuries. A cheap price to pay, especially if you are one of the victims, or potential victims. Israel already has a radar system in place that gives some warning of approaching rockets. Iron Dome will use that system, in addition to another, more specialized radar in southern Israel.

The rocket attacks had been around since 2001, but got much worse once Israel pulled out of Gaza in August of 2005. This was a peace gesture that backfired. From 2001 to 2005, about 700 rockets had been fired from Gaza into Israel. Since the 2005 withdrawal, over 3,200 more rockets have been fired into Israel. The rate of firings increased after Hamas took control of Gaza in June, 2007.

Hamas has been bringing in more factory made Iranian and Chinese made BM-21 and BM-12 rockets. Israeli intelligence officials believe Hamas currently has, in Gaza, several hundred factory made BM-21 rockets, each with a range of 20-40 kilometers. They also have some shorter range (six kilometers) B-12 rockets. These are not smuggled in much, because the locally made Kassam II has about the same range. However, the B-12 is more reliable (more reliable trajectory and fuze, so more are likely to land where aimed and explode.)

The B-12 is a 107mm, 42 pound, 107mm, 33 inch long, Russian designed rocket that is very popular with terrorists. This rocket has a range of about six kilometers and three pounds of explosives in its warhead. Normally fired, from a launcher, in salvoes of dozens at a time, when used individually, it is more accurate the closer it is to the target. This 107mm design has been copied by many nations, and is very popular with guerillas and terrorists because of its small size and portability. There is a Chinese BM-12 variant which has a smaller warhead and larger rocket motor. This version is supposed to have a range of about 12 kilometers.

The 122mm BM-21s weigh 150 pounds and are nine feet long. These have 45 pound warheads, but not much better accuracy than the 107mm model. However, these larger rockets have a maximum range of 20 kilometers. Again, because they are unguided, they are only effective if fired in salvos, or at large targets (like cities, or large military bases or industrial complexes.) There are Egyptian and Chinese variants that have smaller warheads and larger rocket motors, giving them a range of about 40 kilometers.

The rocket attacks from Gaza have been remarkably ineffective, killing only 37 people (half from rockets, the rest by mortars) in eight years. Hamas has had to fire about 270 rockets or mortar shells for each Israel soldier or civilian they have killed. Israeli counterfire killed or wounded a Palestinian for every three Palestinian rockets or mortar shells fired. One Israeli was killed or wounded for every 40 rockets or mortar shells fired. Israeli fire was much more accurate, with most of the Palestinian casualties being terrorists or others involved in building or firing the rockets and mortars. Hamas has tried to get civilians killed, by storing rockets in residential areas, and forming them from those neighborhoods as well. Although Hamas believes in the concept of "involuntary martyrdom" (getting civilians killed for the cause, even if the victims are not willing), many of its chosen candidates for it are not eager to die. So civilians stay away from areas where the rockets are launched, and try to conceal the fact that rockets are hidden under their homes.

Meanwhile, up north in Lebanon, Hezbollah have stockpiled over 40,000 factory made rockets, mainly BM-21s brought in from Iran via Syria. This is three times as many rockets as they had in the Summer of 2006, when over 4,000 rockets were fired into northern Israel, killing about fifty people, most of them civilians. Over a thousand Lebanese died from Israeli counterattacks. Hezbollah and Hamas plan to launch a joint rocket attack on Israel eventually. The Israelis have been planning more effective countermeasures, which they have not been discussing openly. There is also the option of installing Iron Dome in the north, but that has not been assured yet.