November 20, 2012:  Israel has bought seven batteries of Iron Dome anti-rocket missiles. Four are in action and a fifth one entered service several weeks early (on November 17) because of the major rocket assault Hamas and other Islamic terror groups in Gaza launched on November 14th. Over 500 rockets were launched during the first two days, but then the number began to decline. On Saturday (the 17th) 230 rockets were fired, with only 156 on Sunday, and 121 on Monday. While the Palestinians have fired over a thousand rockets into Israel so far, and killed three Israelis, their effort is faltering and the Israeli response is not. Few of the rockets landed in occupied areas. That’s because Iron Dome has been able to detect and destroy 90 percent of the rockets that were going to land in an area containing people. The Israeli military says they have shot down over 300 rockets so far.

Iron Dome uses two radars to quickly calculate the trajectory of the incoming rocket 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, guided missiles are 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 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, and few of those that did hit inhabited areas caused casualties. Israel already has a radar system in place that gives some warning of approaching rockets. Iron Dome uses that system, in addition to another, more specialized, radar in southern Israel.

The Palestinians had been making and breaking ceasefire deals for years but threw away all pretense of making peace after one of the Israeli retaliatory air strikes killed the head of Hamas military operations. Israel had threatened to resume its missile attacks against Hamas leaders if the rocket and mortar attacks on southern Israel did not stop. So on the 14th Israel began shooting at Hamas leaders again and Hamas decided it was time for a major attack against Israel, if only to protect the terrorist group leadership.

Five years ago an Israeli campaign against key terrorist personnel severely restricted the movements of Hamas leaders and forced the terrorist group to agree to a ceasefire. But that deal has fallen apart now because Hamas would not control the smaller Islamic terror groups who continued to attack Israel. Now that Israel has resumed its attacks on all terrorist leaders in Gaza, Hamas is screaming “war crimes” (and getting some support in the West), but the resumption of these attacks appears to be the only thing that can get the Hamas leadership to keep their word. On the down side, the smaller Islamic terror groups in Gaza have become larger and now threaten civil war and the possibility of Hamas rule ending (to be replaced by an even worse crew of Islamic radicals). The only other Israeli option is a ground campaign, like the one in 2009. But that risks more Israeli casualties. Israel does not want to send in ground troops, as this will lead to more Israeli deaths. But the ground operation is obviously an option given the large force of Israeli troops and armored vehicles now gathered at the Gaza border.

Since Hamas is a big believer in using civilians as human shields (often against their will), a ground campaign would get a lot more Palestinians killed. So the attacks against specific terrorist leaders are seen as the better option. Even this risks civilian casualties because Hamas puts its government and military facilities in residential neighborhoods. It has also, on the advice of its Hezbollah advisors, built rocket launchers near mosques, schools, hospitals, and residences. The Israelis have distributed lots of videos of Palestinian rockets being fired in this way. Still, most Arab and some Western media keep maintaining that Israel is at fault for defending itself or simply existing.

This latest war with the Palestinians has been a major test for the Iron Dome system. Each battery has radar and control equipment and four missile launchers. Each battery costs about $37 million, which includes over fifty Tamir missiles (costing $40,000 each). In the two years before this month Iron Dome had intercepted over 100 rockets headed for populated areas. In the last week Iron Dome has intercepted at least another 300 rockets.

The Palestinians are believed to have tried to defeat Iron Dome by firing a lot of long range missiles simultaneously at a few cities. In theory this could overwhelm one or two Iron Dome batteries. But Israel is keeping 24/7 UAV watch on Gaza and have so far spotted attempts at large scale simultaneous launchers and bombed many of the launch sites. This has resulted in many rockets destroyed on the ground or launching erratically and landing within Gaza or nowhere near where they were aimed. Because Iron Dome can track hundreds of incoming missiles, quickly plot their trajectory and likely landing spot, and ignore the majority that will not land near people, the Palestinians have to put hundreds of larger (long range) missiles into the air at the same time to be sure of causing lots of Israeli casualties. So far the Palestinians have been unable to get enough rockets into the air at the same time and at the rate Israeli aircraft are bombing Hamas rocket storage sites (and setting off secondary explosions of the rockets to confirm the hit), the Palestinians will be out of rockets in another week or so.  

Earlier this month Israel successfully completed tests of new software for its Iron Dome anti-rocket system. The improvements enable the Iron Dome missiles to intercept incoming rockets farther away. The 90 kg (200 pound) three meter (9.8 foot) long Tamir missiles use a proximity fuze to detonate near the incoming rocket.

The Palestinian rocket attacks have 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 were fired from Gaza into Israel. Since the 2005 withdrawal, over 5,000 more rockets were 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. Israel believes Hamas currently has, in Gaza, factory-made BM-21 rockets, each with a range of 20-40 kilometers. They also have some shorter range (six kilometers) Russian designed B-12 rockets. The 122mm BM-21s weigh 68.2 kg (150 pounds) and are 2.9 meters (nine feet) long. These have 20.5 kg (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, 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. Israel believes there are dozens of Iranian Fajr rockets, with a range of 70 kilometers, plus several hundred extended-range (40 kilometers) 122mm rockets, and even more standard range (20 kilometers) 122mm rockets in Gaza. There are believed to be over 10,000 rockets stored in Gaza. Iron Dome was designed to detect and hit those with a range of 10 kilometers or more, as these could reach more heavily populated areas of Israel. While Hamas always hinted at negotiating an extended ceasefire with Israel, it still maintained that the ultimate goal is the destruction of Israel.