A trail of fiery lights whizz across the night sky. They abruptly stop, explode, and a boom ricochets off every surface. During the day, they leave trails of vapour, clouds of smoke. The displays are no spectator show; they’re rockets and missiles stopped before they’ve ever found their target.

Israel’s so-called Iron Dome missile defence system has been protecting its citizens for most of this century. It has intercepted thousands of rockets, lobbed by militants from neighbouring areas. The spotlight has now swung to its northern border, across which militant group Hezbollah in Lebanon has been firing rockets for a year.

In September, as Israel ramped up strikes in retaliation against the Hezbollah rocket attacks, the Iron Dome was in action, including, for example, in seaside Haifa, where air sirens sounded for the first time since Hamas attacked Israel on October 7. Tel Aviv has also woken to sirens warning of a Hezbollah missile aimed at the capital – the first time the militant group in Lebanon has fired a missile able to reach into central Israel.

Israel’s air campaign against Hezbollah is showing no signs of stopping. And Hezbollah, one of the most armed non-state actors in the world, could put Israel’s missile defence system to the test, even though it has taken a number of blows in recent days. “Hezbollah still has large amounts of munitions available,” says Malcolm Davis, a senior analyst at the Australian Strategic Policy Institute. “And so what you are likely to see is some sort of response by Hezbollah in the coming week or so, which could be quite significant in size.”

So, what is the Iron Dome? Could Hezbollah overwhelm it? And what could the next stages of this conflict involve?

What is the Iron Dome?

Israeli efforts to develop a missile shield go back four decades. In 1986, Israel and the United States signed a memorandum of understanding to develop missile defence, tied to US president Ronald Reagan’s Strategic Defense Initiative (known as Star Wars). Efforts were stepped up in 1991 when Iraq fired conventionally armed Scud missiles at Israel during the Gulf War, according to Peter Dombrowski and Catherine McArdle Kelleher in a 2013 analysis. “Since then, Israel and the United States have co-operated on several missile-defense programs, including joint technology development, industrial co-operation, and a program of testing and exercises in addition to shared funding,” they write. “Far more than the United States, Israel sees its adversaries’ air and missile capabilities (including conventionally armed ballistic missiles) as part of a continuous spectrum of threats to its population and forces.”

Israel began work on Iron Dome after its 34-day war with Lebanon in 2006. Its first mobile battery (more on them in a moment) was rolled out in March 2011 on the outskirts of Beersheba, a town in southern Israel, after a bout of rocket attacks by militants in Gaza. In April of that year, the IDF said it had used the Iron Dome to intercept its first missile, a rocket from Gaza targeting the coastal city of Ashkelon. According to the Centre for Strategic and International Studies, the Iron Dome was further developed with assistance from the United States between 2012 and the 2014 Gaza conflict, by which time nine batteries were operational. CSIS reports that during that conflict some 4500 rockets and mortars were launched into Israel; around 800 were identified as a threat to life; 735 were successfully intercepted.

In essence, when a short-range missile, rocket or drone hurtles towards Israel, a sophisticated system on the ground works out whether to counter the incoming projectile with its own missile or not. It is designed to ignore those that don’t pose an obvious threat.

Today, the Iron Dome consists of at least 10 sites in Israel that form a shield against the common types of projectiles its neighbours have used to threaten it. Each site is called a “battery” and includes three components: radars; three or four launchers, each holding 20 interceptor missiles; and a manned control centre from where defence personnel oversee interceptions. “What humans do is analyse the attack profile that’s coming in and then, essentially, work out how best to counter it,” says Malcolm Davis. “And then the Iron Dome System is automated, in the sense that you’re not having humans launching individual missiles.”

The system can down rockets launched from between four and 70 kilometres away (roughly the distance from, say, Lebanon’s south to Haifa, or from Gaza to Tel Aviv.) For shorter-range attacks, the process from radar detection to interception can take less than 30 seconds, says Iain Boyd, director of the Centre for National Security Initiatives at the University of Colorado.

One of the system’s strengths is its mobility. “It’s not a fixed thing,” says Michael Shoebridge, director of Strategic Analysis Australia. “You can relocate the systems and position them if the threat changes. It also means as far as targeting them to destroy them, that’s harder because they can move.”

Israeli company Rafael Advanced Defense Systems says the Iron Dome has a 90 per cent interception rate. “It has proven extremely effective since last year since the Hamas attacks,” says Shoebridge. Still, some rockets fired by Hezbollah across the Blue Line that is the de facto border between it and Israel have caused destruction, not least one that killed 12 children at a soccer field in the Golan Heights in July.

The Iron Dome is not Israel’s only missile defence system – “it’s the poster child,” says Shoebridge – instead forming part of a layered approach. Israel defends itself against potential long-range ballistic missile attacks with “Arrow 3”, capable of shooting down missiles from as high as space, while “Arrow 2” protects against medium-range missiles fired through the upper atmosphere. The Arrow system uses radar and satellite technology, says Davis. “If they detect an Iranian missile being launched, they would immediately get a notification from the satellite that would then give them a missile tracker.”

Another layer is David’s Sling, capable of intercepting missiles from 40 to 300 kilometres away. It is designed to spot ballistic missiles, cruise missiles, aircraft and drones. Israel had rarely used the system before the Gaza War – and has used it sparingly since, including to shoot down several Hamas projectiles aimed at Tel Aviv and Jerusalem in 2023. In September, it also intercepted a Qadr 1 ballistic missile launched from Lebanon towards the headquarters of Israeli intelligence agency Mossad in Tel Aviv, a high-value target that Hezbollah deemed “responsible for the assassination of leaders and the explosion of pagers and wireless devices”.

The IDF also has radar-directed cannons and machine guns to deploy against short-range rockets and drones. “They’re like multiple umbrellas,” Shoebridge says of the overall system. “Each umbrella can be porous, and that’s why you need multiple layers.”

Can Hezbollah rockets overwhelm the Iron Dome?

The deadly October 7 attack on Israel showed that the Iron Dome could be penetrated. Hamas-led militants fired an estimated 3500 missiles from Gaza on that day, most in a short timeframe, providing cover for the trucks, motorbikes and even a paraglider they used to cross into Israel where they killed nearly 1200 people.

The system has a saturation point, although this point is not publicly known. Hezbollah has built up a significant arsenal – the CSIS estimates it had about 200,000 rockets or more in March – but the strength of these weapons is patchy. “Some are ‘homemade’ – and generally ineffective – and some come from Iran and Syria [and are] more reliable,” says Iain Boyd. Many are thought to be unguided: “point and shoot” rockets that might be effective on the battlefield at short range but tend to be wildly inaccurate at longer distances.

Martin Kear, an academic specialising in resistance movements and Middle East politics at the University of Sydney, says it appears Hezbollah does have a large arsenal of long-distance weapons “but we need to make the distinction between rockets and missiles”. “The rockets they have are unguided subsonic weapons that are only a couple of stages advanced from what the Russians used during the Second World War … it’s a quantum leap between those rockets and missiles.”

Marcus Hellyer, head of research at Strategic Analysis Australia, says most of the rockets that the Iron Dome ignores land in uninhabited places such as fields. “They may have small numbers of more sophisticated [weapons],” he says of Hezbollah, “but the bulk of them just seem to be ones that you put on a rail launcher and launch them in the wide general direction of their target.”

Too many rockets approaching is one way a missile defence system can be overwhelmed, or the Israelis could simply run out of interception missiles. Whether the Iron Dome could be overcome is partly down to a simple equation, says Boyd: “How many rockets and missiles does Hezbollah have against the number of interceptors that Israel has.”

This is one reason for Israel recently ramping up its offensive against Hezbollah. Says Hellyer: “If you can use one bomb to take out 50 rockets, that’s much more economical than having to lob 50 or 100 Iron Dome missiles.” The Israel Defence Forces says it has struck more than 2000 Hezbollah targets in the past week, including the sites of rockets, missiles and launchers, some of which it claims are hidden under civilian infrastructure. The strikes have led to the deaths of more than 700 people, according to Lebanon health authorities.

Israeli airstrikes also killed Hezbollah’s leader of three decades, Hassan Nasrallah, along with several other senior figures, including the heads of its southern front and special operations forces. These attacks, along with a covert operation to boobytrap and detonate Hezbollah’s pagers and walkie-talkies, have stunned the militant group and diminished their ability to retaliate. “The command and control has been really badly damaged,” Shoebridge says. “So their ability to do highly orchestrated, co-ordinated attacks is probably quite reduced.”

What could happen next?

Israeli Prime Minister Benjamin Netanyahu insists the attacks against Hezbollah will continue until 60,000 displaced Israelis can return to their homes in northern Israel. Netanyahu told the United Nations on Friday there is “no place” that its weapons could not reach in the Middle East.

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Says Shoebridge: “If you look at the balance between what the Israelis are doing offensively to reduce Hezbollah’s ability to attack them, and then the effectiveness of their multilayered defensive system, I think the Israelis have the advantage. That’s a big shift because Iran, Hezbollah and Hamas were banking on their overwhelming advantage in rocket and missile arsenals, and it looks like the Israelis are able to destroy that advantage.”

Still, Israel’s aim of securing its north will be difficult to achieve. Whether it can do so simply through an air campaign seems doubtful, says Rodger Shanahan, an Australian Defence Force member who served in Lebanon between 1998 and 2006. On the other hand, Hezbollah doesn’t necessarily need precise missiles to disrupt Netanyahu’s aims. “So if you’ve got limited strategic aims, which is to deny Netanyahu the political success that he’s publicly said is going to happen – and you’re in chaos at the moment because of all the people who have been killed – you just need to get a couple through every now and then, even if they land in the field, that’s fine,” says Shanahan. “People who aren’t in northern Israel are going to go, ‘It’s not safe yet.’”

Meanwhile, so far, Iran does not appear to be coming to Hezbollah’s aid. In a statement responding to Nasrallah’s death, Iran’s leader Ali Khamenei said the fate of the region would be determined “by the resistance with Hezbollah at the top”. Malcolm Davis believes Hezbollah will respond further, though. “I think that what we will see in the coming week is a significant Hezbollah response. Israel will continue attacking. There’s a discussion at the moment about, should they go in on the ground? I think that’s quite possible.”

Unlike the 1990 Gulf War that had a combat phase of six weeks, Davis can’t see a quick resolution. “I think one of the lessons from both Ukraine and the Middle East: we should not assume there is a quick exit from these conflicts.”

Sometimes both sides have to fight a protracted war, he says. “We need to accept the fact that this is the sort of thing that can happen even with all the modern military technology we have.”

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