How Israel's Iron Dome missile defence system works

Israel is fast running out of interceptor missiles for its famed Iron Dome defence system, which is known as "the envy of other militaries".

As Israel prepares to launch strikes against Iran, which fired around 200 missiles at Israeli targets earlier this month, military analysts have warned it may not have enough defensive missiles to withstand a coordinated retaliation from Tehran and its proxies across the region.

The US is "racing to help close gaps" in Israel's protective shield, said the Financial Times (FT), deploying Terminal High-Altitude Area Defense (Thaad) antimissile batteries and – unusually – a US crew to operate them.

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The US announcement "underlines its growing concern about ballistic missiles targeting Israel", said the BBC. This is despite it having "the best anti-missile defences in the world", said Richard Kemp in The Telegraph.

What is the Iron Dome and how does it work?

The Iron Dome is a three-piece system of interceptor batteries that shoots short-range rockets, artillery shells and mortars out of the sky. A radar tracks the missile as it is fired at Israel, and then advanced software predicts the rocket's trajectory. The information is used to guide Tamir interceptor missiles, which are fired from the ground to destroy the missile.

The system was built by the Israeli state-owned company Rafael Advanced Defense Systems in response to the war with Lebanon's Hezbollah in 2006, when 4,000 rockets rained down on northern Israel, killing 44 people. The Iron Dome was first used in March 2011 and made its first successful intervention the following month, when it intercepted a Grad rocket fired from Gaza.

Consisting of a series of truck-towed mobile units placed strategically throughout the country, the system, known as Kippat Barzel in Hebrew, reacts within a matter of seconds and is manned 24 hours a day. It was originally designed to protect cities and strategic sites against missiles with a range of between 2.5 and 43 miles, but is "thought to have been expanded", said Sky News.

Running the world's most advanced anti-missile defence shield does not come cheap, however. According to Jean-Loup Samaan, a senior research fellow at the University of Singapore's Middle East Institute, just one of the Tamir interceptor missiles is estimated to cost around $50,000 (£38,000).

Funding was originally met by Israel, "but because of the high cost of the system, the country has had to rely on its long-time ally, the United States", said Euronews. According to the US State Department, Washington has provided Israel with billions in funding for missile defence since 2009, but given the strain put on the Iron Dome system over the past year, this is still not enough, prompting the US to step in and supply additional ballistic support directly.

How effective is it? 

Over the past decade, the Iron Dome has proved to be "particularly effective", said Euronews. Israeli authorities claim it has a success rate of more than 90%, "although some defense analysts question those numbers", said The Washington Post.

Iron Dome quickly became the "envy of other militaries", said Sky News. It is "not perfect", however, and "has a saturation point at which it would become overwhelmed, but this exact level is unknown".

Since 7 October 2023, the FT said Israel's triple-layered air defences have shot down the "vast bulk" of incoming drones and missiles fired by Iran and its proxies such as Hamas in Gaza, Hezbollah in Lebanon, Houthi rebels in Yemen and Iraqi militias.

In April, in what one official described as "the most complex air defence events recorded", Israel claimed to have successfully shot down 99% of the 330-plus drones, cruise and ballistic missiles fired from Iran.

But it had less success fending off a second Iranian barrage of over 180 ballistic missiles fired on 1 October. Almost three dozen missiles hit Israel's Nevatim air base, according to open-source intelligence analysts, while one missile exploded 700 metres away from the headquarters of Mossad, Israel's intelligence service.

Then on Sunday, in what the i news site described as a "rare breach" of Israeli airspace, a Hezbollah drone attack killed four soldiers and wounded around 60 others after successfully bypassing the Iron Dome to hit an Israel Defense Forces base north of Tel Aviv.

This highlights the Iron Dome's "fatal flaw", said The Telegraph. "While most of the focus has been on Hezbollah's huge collection of precision-guided missiles, Israel has found that much smaller and less aggressive drones are posing just as big of a challenge, if not bigger."

In short, "it wasn't designed to deal with drones".

What is the solution? 

The fact that Hezbollah was able to fire an undetected drone and strike an Israeli air base, killing several soldiers, raises "serious security questions" for Israel, said The Telegraph.

Israel's Channel 12 reported that Hezbollah successfully deceived the Israeli air defence system by firing a barrage of missiles to cover the drone and now defence chiefs are concerned the prospect of further drone "swarms" could overwhelm urban centres.

While the Iron Dome is primarily designed to defend against missiles, Israel appears to have been blindsided by the emergence of a new, remotely operated fibre-optic generation of drones. They have been deployed to great effect by Russia in Ukraine and are "virtually undetectable by radar and difficult to intercept", said local Israeli media.

In response, Israel is "fast-tracking" its new Iron Beam laser defence system, i news said.

With a range of just under 10 miles, it is specifically designed to counter drones at a lower cost, but is not projected to be operational until June 2025.

"Israel is speeding up its research into laser drones to increase its defense capabilities, but these innovations won't be ready for deployment for a few more months," said Noam Ostfeld, from geopolitical risk consultancy Sibylline. When they are "they will be used alongside the Iron Dome defence system, adding another layer of defence against drones".