Here is a good article about Iron Dome

[hack89]

So far Iron Dome has shot down 85 percent of the rockets it calculated were headed for a populated areas. The Tamir missiles used by Iron Dome weigh 90 kg and have a range of 70 kilometers against rockets, mortar shells and artillery shells up to 155mm. Iron Dome can also shoot down aircraft and helicopters (up to 10 kilometers/32,000 feet altitude). Iron Dome is the principal defense against short range rockets fired from Gaza or Lebanon. Work is underway to increase Iron Dome range from 70 to over 200 kilometers.

Hamas has already (in 2012 and 2014) 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 able to keep 24/7 UAV watch on Gaza and spot attempts at large scale simultaneous launchers. This enables Israel to bomb or shell many of the launch sites. This results 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, Hamas needs 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 Hamas has not been unable to get enough rockets into the air at the same time to make this work. They may never get this to work, because they have to hide preparations for the simultaneous launch of many rockets and this is very difficult to do undetected.

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 Israeli withdrawal, over 5,000 more rockets were fired into Israel. The rate of firings increased after Hamas took control of Gaza in June, 2007. In 2011 700 rockets and mortar shells were fired, this jumped to 2,300 in 2012 when Hezbollah briefly went to war with Israel. The retaliation was so effective that Hezbollah agreed to a ceasefire. Thus since the early 2013 ceasefire until early 2014 only a few hundred rockets and mortar shells have landed in Israel. That changed in July 2014 when Hamas began another major rocket campaign. Hamas fired about a thousand rockets in the first week, and Iron Dome saw to it that no Israelis died. Israeli warplanes, artillery and commandos saw to it that more than a thousand Hamas rockets were destroyed on the ground. But unless a lot more rockets can be destroyed on the ground, the Hamas barrage will use up the inventory of Tamir missiles

http://www.strategypage.com/htmw/htada/articles/20140716.aspx

To me the value of Iron Dome is simple - by keeping Israeli casualties very low, it significantly reduces public pressure on Israeli leaders to invade Gaza, with the enormous casualties it would entail, to permanently eliminate the rocket threat. Conversely, Iron Dome is most likely the only reason Hamas is still around.

[Jefferson23]

1. Israeli Rocket Defense System Is Failing at Crucial Task, Expert Analysts Say

Although it appears to hit incoming Hamas rockets, Israel’s system could be falling short of detonating the rockets’ warheads.

By David Talbot on July 10, 2014

Even though Israel’s U.S.-funded “Iron Dome” rocket-defense interceptors appear to be hitting Hamas rockets in recent days, they are almost certainly failing in the crucial job of detonating those rockets’ shrapnel-packed explosive warheads, expert analysts say.

As a result, rockets fired from Gaza are probably plunging to the ground with intact explosives. The fact that they aren’t causing injuries or deaths in Tel Aviv, Jerusalem, and other cities is mainly a matter of luck, the analysts add.

On Thursday, the Israel Defense Forces said missiles from the system had intercepted 56 rockets fired out of Gaza, preventing strikes in several cities. Yet Richard Lloyd, a weapons expert and consultant who is a past Engineering Fellow at Raytheon Integrated Defense Systems, says that because these interceptions had almost certainly not detonated the rockets’ warheads, the system is essentially failing.

http://www.technologyreview.com/news/528916/israeli-rocket-defense-system-is-failing-at-crucial-task-expert-analysts-say/#comments

[hack89]

2. Raytheon wants more money for Iron Dome missile upgrades

they are Israel's partner in Iron Dome and stand to make hundreds of millions if Israel and the US commit to upgrading the Tamir missile.

[Jefferson23]

3. The increase was just doubled, not approved yet by the congress..I believe.

That is big bucks.

[hack89]

4. It is still in committee

The Senate Appropriations defense subcommittee approved a defense spending bill on Tuesday that would provide $621.6 million for Israeli missile defense, including $351 million for the Iron Dome system that intercepts short-range rockets and mortars. In the latest hostilities between Israel and Hamas, Iron Dome has been successful in shooting down rockets and preventing Israeli deaths.

http://news.yahoo.com/senate-panel-doubles-money-israels-iron-dome-153116074--politics.html

Raytheon wants to ensure there are enough votes to get it into the final budget and passed into law.

[Jefferson23]

9. I bet they do..the amount of money is incredble. n/t

[FBaggins]

5. Could?

Is there any evidence provided at all that they are "probably" falling with intact explosives?

Either way... it would be more than just "luck". A rocket aimed at a city is going to do far more damage if it hits than one that falls to earth in far-less-populated areas.

[Igel]

7. Criticizing it to help improve it is a valid activity.

Many criticize it for not doing a job in addition to the most essential one in hopes of making sure that it's discontinued, that it's use doesn't spread, to avoid the production of similar systems. Not because it doesn't do that other job, but because they don't want it to do the first job.

After all, if the truly evil people have a defense against missiles, what's to stop the fascists from using their own against the good, righteous people of the world?

Of course, that's the argument against the US' development of ABM systems. I mean, it's to the point that many believe it's been conclusively proven that ABM systems simply can never work. Last go-around, Iron Dome was severely critiqued for not shooting down a lot of missiles that it didn't bother to aim at, in order to substantiate the idea that Iron Dome can't work. 85% success rate sounds pretty good for "it can't work." Unless, of course, we insist on a 100.00000% success rate as the minimum standard.

[FBaggins]

8. Sure... but not if you're making up the criticism.

I could post that while the iron dome appears to be knocking out most of the incoming rockets, we don't know for certain that those rockets aren't being transformed into carnivorous pink elephants that burrow underground until five years later when they all emerge to slaughter the entire human population.

Obviously... that's a bad thing... so we can't really say that Iron Dome is at all successful! Surely we can agree that being slaughtered by carnivorous pink elephants is worse than letting a few rockets hit their targets! Right?

Of course, that's the argument against the US' development of ABM systems. I mean, it's to the point that many believe it's been conclusively proven that ABM systems simply can never work.

Yep. Enough people opposed Star Wars for then-reasonable reasons... but somehow stuck on the notion that it could never work (not that it was too expensive and not feasible at the time). Maybe they worry that they'll look as though they were wrong way back then.

[shaayecanaan]

11. i dont think that the criticism was that "it couldnt work"

the criticism was that the US could spend an awful lot of money for something that could easily be defeated by relatively simple countermeasures. That criticism continues to hold true. The counterargument is that ABM is not intended to defend against proper missiles but only against very limited numbers of missiles without such countermeasures (such as might be expected from countries like North Korea).

[shaayecanaan]

10. I've read success rates of 95%, 85%

and from the IDF themselves, 74% to 92% (whatever that means).

There are three problems with gauging its true success rate:-

1) Hamas' rocket fire was never very lethal to begin with. Some 15,000 rockets and mortars have been fired for a total of 28 deaths. That is a low rate of lethality, but it gets much, much lower when Hamas attempts to hit cities outside of Gaza's immediate environs such as Ashdod and Ashkelon. It is very difficult to hit those cities reliably with unguided artillery rockets, and even when you do, you have to sacrifice payload for propellant to get the rockets that far. The rockets are really a psychological weapon at that range, and very little more.

2) The only city that ever suffered a significant number of dead was Sderot. Most of the vulnerable people have moved out of Sderot (25% decrease in population). Israel have built a large number of shelters and many people have fortified rooms that will survive even a direct hit from a rocket. Hamas have been hitting Sderot and other large cities (there have been several large fires) but those hits have not been causing deaths like they used to.

3) The lethality rates are not greatly changed from where they used to be. In Cast Lead, Hamas fired 800 rockets, killing three. This time they have killed one from a mortar. The death of three in Cast Lead was first blamed on the victims, because they didnt run to a shelter fast enough, but belatedly the Israeli military admitted that there was a "malfunction" with Iron Dome. Apparently the interceptors had not fired. It is uncertain as to whether, statistically, the failure of Iron Dome to fire an interceptor counts as a "failure" when measuring its success rate, or whether the IDF simply assesses the chances of an interceptor damaging or diverting a rocket once it is fired.

[bemildred]

6. Israel to deploy three new Iron Domes

Jerusalem - Israel has found funding for three new Iron Dome rocket interception batteries, an Israeli official said on Tuesday, a week into its conflict with Palestinian militants in Gaza.

Israel had seven Iron Domes set up to shoot down missiles when cross-border fighting with Hamas-led militants surged on 8 July, and has since brought two more into service, Israel's Defence Ministry said.

Speaking to Reuters on condition of anonymity, the Israeli official said that as a result of the Gaza crisis, three new Iron Dome units were now "in the pipeline".

Israel accepted the terms of an Egyptian-proposed truce on Tuesday to end its air strikes and naval barrages on Gaza that Palestinian officials say have killed at least 184 people, mostly civilians, since Tuesday last week.

http://www.news24.com/World/News/Israel-to-deploy-three-new-Iron-Domes-20140716