How does Israel's defense system against Iranian missiles work and how much does it cost?

After Iran launched missiles at Israel on October 1, many fake or out-of-context videos appeared on the social media platform X, showing footage of missiles attacking Israel.

Some users were quick to claim that Israel's vaunted Iron Dome defense system had failed. Others speculated that Israel may have deliberately let the Iranian missile land on its territory to set a precedent for retaliating against Iran.

However, such claims are false.

Even if a missile hits an open area in Israel, that does not necessarily indicate a failure of the Iron Dome system or that the missile was deliberately landed as part of a strategy to retaliate against Iran.

And in this particular case, it appears that Israel may not have relied on the Iron Dome defense system.

What missiles did Iran use?

Iran has reportedly fired about 180 ballistic missiles into Israeli territory.

Ballistic missiles operate on the principle of providing initial energy by a powerful engine to lift the missile to a very high altitude and speed. After the engine stops working, the missile will switch to a free flight phase following a parabolic trajectory, like a bullet being shot up high. This trajectory is called a ballistic trajectory.

During the free-flight phase, the missile no longer has a propulsion engine and is only affected by gravity and air resistance (if it is still moving in the atmosphere). Therefore, the missile cannot adjust its flight direction during this phase. The range and accuracy of a ballistic missile depend on many factors, including launch angle, initial velocity, warhead type and meteorological conditions.

Israel claims that, with the help of the US and UK, it shot down most of the Iranian missiles, although some damage may have been done to Israelis. A BBC journalist in Lebanon said the missiles may have hit Israeli military bases as well as a restaurant and a school.

Meanwhile, Iran's Islamic Revolutionary Guard Corps claimed that 90 percent of its missiles hit their targets, including three military bases.

It's still unclear what type of missile Iran used, although experts told CNN based on the videos that Iran likely fired the Shahab-3, a medium-range missile capable of flying about 500 to 600 miles.

Some Iranian media reports suggest that Iran may have also deployed the Fattah-1 hypersonic missile.

How does Israel's defense system work?

Israel's most famous air defense system is the Iron Dome, produced by domestic companies Rafael Advanced Defense Systems and Israel Aerospace Industries. On its website, Rafael Advanced Defense Systems claims that the Iron Dome defense system has intercepted more than 5,000 rockets with a success rate of over 90%.

The Iron Dome defense system has helped repel numerous Hamas attacks over the years. However, this time it appears Israel is relying on other defense mechanisms, as the Iron Dome is only used against short-range rockets and has a range of up to 43 miles.

One of them is David's Sling, which has a range of 25 to 190 miles and is designed to intercept medium-range threats.

For longer-range missiles, Israel uses the Arrow 2 and Arrow 3, which operate outside the atmosphere. The Arrow 3, for example, is said to have a range of more than 1,500 miles.

All of these systems include missile defense systems equipped with missile launchers and radars capable of detecting missiles and other threats, such as drones, aircraft, and other projectiles.

Once the missiles are detected, artificial intelligence (AI)-powered algorithms will help determine the trajectory of the missiles and interceptor missiles will be fired from launchers to destroy them.

The Iron Dome defense system could also allow short-range threats to strike the ground if it determines the missile is headed towards an uninhabited area, thus saving on the cost of interceptors.

How much does it cost Israel to shoot down a missile?

While estimates suggest that building a missile for Iran could cost around $100,000 or more, the cost for Israel to destroy these threats is believed to be much higher.

Reem Aminoach, a former brigadier general and financial adviser to the head of the Israeli army, previously told Bloomberg that repelling Iran’s previous attack in April may have cost Israel about $1.1 billion. At that time, Iran fired more than 120 missiles, 30 cruise missiles and deployed about 170 drones.

A significant portion of the cost of repelling such an attack is spent on interceptor missiles. The cost of a David Sling missile is estimated at around $1 million, while some say firing an Arrow missile could cost around $2 million.

According to the Guardian, a former financial adviser to the Chief of Staff of the Israel Defense Forces (IDF) said an Arrow missile typically costs $3.5 million.

Considering Israel's reliance on the Arrow missile, the cost of the interceptor alone could run into at least several hundred million dollars.