In response to the killings of senior Hamas, Hezbollah and Revolutionary Guard leaders, Iran has used some of its most powerful weapons to launch a major attack on Israel.

Sirens wailed and skies lit up across the country as nearly 200 ballistic missiles were fired from Iran on Tuesday evening.

Experts say it was the largest ballistic missile attack on a nation-state in history.

But despite the scale and force of the attack, Israel said most of the rockets were intercepted by its Iron Dome and a range of air defense systems.

What is the Iron Dome?

ABC reporters in Israel reported seeing a hail of rockets raining down overhead.

Explosions rocked Jerusalem and the Jordan Valley as residents were ordered to shelter in bomb shelters.

But instead of the missiles hurtling toward targets, many of them exploded in the air through the country's Iron Dome and air defense network.

No injuries were reported in Israel, but one man was killed in the occupied West Bank, authorities there said.

The Iron Dome is considered one of the most advanced air defense systems in the world.

It was specifically designed to deter rocket attacks from neighboring militant groups, particularly Hamas and Hezbollah, using short-range missiles.

The system uses radars to detect incoming threats such as rockets, missiles, mortars and drones.

It then fires its own interceptor missiles to take them out.

The system determines whether a missile is on track to hit a populated area.

If not, the rocket is ignored and allowed to land harmlessly.

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It was developed by Rafael Advanced Defense Systems with US support and became operational in 2011.

According to the Israeli military, it has since intercepted thousands of projectiles fired by Hamas and Hezbollah.

There are 10 Iron Dome batteries strategically located across the country, providing city-sized coverage against missiles with a range between four and 70 kilometers.

In 2017, a naval version of the Iron Dome was also deployed to protect ships and sea-based assets such as aircraft carriers.

What are ballistic missiles?

Israel said Iran fired more than 180 ballistic missiles in Tuesday's attack.

Behnam Ben Taleblu, an Iran analyst at the Foundation for Defense and Democracy, said the attacks were “record-breaking and historic.”

“Tehran tried to find a way to restore its shattered deterrent and it succeeded in this grotesque way, which involved the largest rocket fire against another nation-state in history,” he told ABC RN Breakfast.

Ballistic missiles are initially propelled by rockets, but then follow an unpowered, free-falling trajectory towards their targets.

Michael Shoebridge, director and founder of Strategic Analysis Australia, said they were fired “like a bullet from a gun”.

When they reach their highest speed, they become ballistic and rise to great heights before diving deep and quickly.

“They form a kind of parabolic arc,” Mr. Shoebridge said.

Iran launched another major attack this year, but did not use any ballistic missiles.

These attacks involved around 300 long-range drones, ballistic missiles and cruise missiles at significantly lower speeds.

Many were shot down by a US-led coalition, others apparently failed to take off or crashed in flight.

What are Iran's Fattah missiles?

Iran's Revolutionary Guards said they used hypersonic Fattah missiles for the first time in Tuesday's bombing and were 90 percent successful in hitting their targets in Israel.

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The Israeli military reported that only a few were killed in central and southern Israel.

Iran unveiled the Fattah (“Conqueror”) missile in June last year, claiming it was a hypersonic missile and could reach speeds of Mach 13-15.

A hypersonic weapon is just something that travels at Mach-5 or faster.

Military analysts say it would be the first time Iran has used the missiles.

The precision-guided Fattah missile has a range of 1,400 kilometers and is said to have maneuverability and “stealth capability” to penetrate radar systems.

Mr Shoebridge said there were different variants of the Fattah missiles.

The longer the range, the higher they can fly and approach their targets at high speeds.

How were so many intercepted?

An Israeli security official said the Israeli Air Force, working with the United States, intercepted many of the missiles.

However, there were a few direct hits that damaged buildings.

Israeli Rear Admiral Daniel Hagari said central and southern Israel received limited attacks.

A video released by the military showed a school in downtown Gadera being heavily damaged by an Iranian missile.

Mr Shoebridge said the Iron Dome was not solely responsible for thwarting most missile attacks.

Israel has a multi-layered air defense system, which he described as “multiple protective umbrellas.”

Israel's three main air defense systems:

• Iron Dome: Intercepts short-range surface-to-surface missiles (lower layer)
• David's Slingshot: Intercepts short to medium and medium to long range surface-to-surface missiles (middle layer)
• Arrow 2 and 3: Intercepts medium to long-range missiles and long-range missiles (upper layer)

Israel also has US Patriot systems in service that can reach further than the Arrow 3.

The long-range systems are designed to extend beyond the Earth's atmosphere.

“With ballistic missiles that leave the atmosphere, they continue to fly and then re-enter the atmosphere until they reach their target,” Mr Shoebridge said.

“It looks like this layered system would have been very effective if Iran had fired about 180 missiles, mostly a mix of ballistic missiles.”

Why is Iran attacking Israel?

Iran described the campaign as defensive and targeted Israeli military facilities.

According to the Iranian state news agency, three Israeli military bases were attacked.

In a statement, Iran's Revolutionary Guards said the attack was in response to the killings of Hamas leader Ismail Haniyeh, Hezbollah leader Hassan Nasrallah and senior Revolutionary Guards commander Abbas Nilforooshan.

The attack also came a day after the Israeli military said its army had crossed the border into Lebanon and was carrying out “local ground attacks” on Hezbollah positions.

Iran has warned Israel that it would face further attacks if it responded.

Israeli Prime Minister Benjamin Netanyahu announced a counterattack.

“Iran made a big mistake tonight – and it will pay for it,” he said at the start of an emergency meeting of the Political Security Cabinet late Tuesday, according to a statement.

Washington also said it would work with long-time ally Israel to ensure Iran faces “serious consequences” for Tuesday's attack.

Experts say further escalation and large rocket attacks could potentially swamp Israel's air defense systems.

And the closer the attacks came to populated cities and the center of the country, the greater the damage from shrapnel and debris would be.

Mr. Shoebridge said even if Iran and its proxies stockpiled thousands more missiles, it would take time to plan large-scale attacks.

“It’s not as easy as firing barrages,” he said.

“And if you fire a very large number of missiles, you will endanger yourself in your preparations and be subject to preemptive strikes to prevent the launch.”

“And that’s exactly what happened to Hezbollah last week.”

ABC/Wires