The Iron Dome system for intercepting enemy missiles and rockets was being hailed as a hero in 2012’s Operation Pillar of Defense. Now, during Operation Protective Edge, its achievements have been even greater. It is hard to imagine the damage and loss of life that would have occurred in Israel without Iron Dome, which has shot down over 900 rockets so far. The 90% interception rate, a slight improvement over its 85% rate in Pillar of Defense, has allowed the home front to keep to a nearly normal routine under fire, buying time for the army to continue with the operation.
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Not only has the Iron Dome battery been a remarkable technological achievement, it was developed in just two years and is unusually cost-effective for such a sophisticated, multifacted system.
But it has not been a financial success for Israel’s defense industry, which developed it. For now, they have only one customer: the Israel Defense Forces. A few governments have expressed interest but, for now at least, no other country in the world faces the same immediate missile threat that Israel does.
The main contractor for Iron Dome is state-owned Rafael Advanced Defense Systems, in collaboration with the Defense Ministry’s Administration for the Development of Weapons and Technological Infrastructure (known as Mafat in Hebrew).
Other contractors involved in the project are Elta Systems – a subsidiary of state-owned Israel Aerospace Industries – which makes the radar system; mPrest Systems, 50%-owned by Rafael and the developer of the command and control system; and Comtec Communications, which developed components for radio communications. The Israel Air Force’s Air Defense Command operates the batteries.
Since Pillar of Defense, the system has been improved and adapted, based on the new threats and types of rockets facing Israel, taking into account the lessons learned from previous battles. There are now nine operational batteries, compared with only five during Pillar of Defense, though the last two were put into operation only after the most recent escalation with Hamas.
“The development of the Iron Dome system is continuous. It is better than its predecessors. We’re staying one step ahead of the other side, which has introduced additional missile systems – not just the M75, but also other new systems,” says Mafat’s Yair Ramati.
One of the fundamental goals in developing Iron Dome was to make it efficient and low-cost. “If you take out the cost of the radar – the most expensive component of the system – the cost of each additional battery is relatively marginal. After that, you can decide how many rockets to intercept and to control costs. It’s not an expense on a level that a country needs to think about,” says mPrest CEO Natan Barak, a colonel in the reserves and commander of the navy’s software unit during Pillar of Defense.
The savings are also expressed in limited manpower needed to operate the system, as well as in operational flexibility. For instance, the system only defends school buildings when they are in use, cutting down the number of interceptor missiles that need to be launched. Each interceptor costs a few tens of thousands of dollars.
“We were asked to develop a very inexpensive system,” explains the head of the project at Rafael, who spoke on condition of anonymity. “We invested a lot of money in developing the interceptor and the system in general. We did some very smart things, and we sought very reliable components and systems. We also used a few innovations of our own that have kept costs down.”
This week, the Defense Ministry ordered the companies involved in Iron Dome not to give interviews or speak to the public for now. “The Iron Dome system has many hundreds of successful interceptions behind it. Since it became operational, many improvements have been made and are being made, which brought about significant improvements in its capabilities. Beyond that, for obvious reasons, we cannot provide details,” a spokesman said.
Nevertheless, a lot is known about how Iron Dome works from previous interviews conducted by The Marker.
The radar, developed by Elta, is an active, electronically scanned array radar that scans the sky for a ballistic motor or rocket. When it detects any, it tracks the rocket’s location and determines its type. This data is transferred to the command and control system, developed by mPrest, which processes and assesses the level of threat and the rocket’s projected target.
If it’s determined that the rocket is going to fall outside a protected area – meaning one that is largely unpopulated and/or of no strategic importance – it won’t be intercepted. If it is, the decision is made that it will be intercepted.
The launcher, which includes up to 20 Tamir interceptor missiles made by Rafael, is operated by the Air Defense Command in the field. An interceptor can act independently and complete its mission, even if it loses communication with the ground, thanks to its sighting systems. The battery also has a communication center that connects all the launchers and interceptors in the region.
The brain of Iron Dome is the command and control center, which synchronizes data from the radar system and other sensors, and decides which targets to intercept.
“The moment we see that the threat is going to reach a protected area, we build the interception plans,” said mPrest’s Barak in an interview with TheMarker during Pillar of Defense. “We construct hundreds of solutions and choose the best one. Then we launch the interceptor at the right time so it will meet the threat in the right place. We need to be able to tell whether it’s one threat or several. There’s a program to match each threat, and we confirm that the interceptor is carrying out the program we expected. If there’s a change in the data, the interceptor gets an update, which is how the interceptor meets the target.”
There are many constraints, because Iron Dome operates in a civilian environment and in areas where aircraft are present.
“These factors make interception relatively complex,” explained Barak. “At short ranges, which are the hardest for us, the reaction time from the moment of detection and the moment we know the rocket is going to fall in a protected area, has to be less than a second. We have less than a second to launch an interceptor.”
And if there’s more than one threat? “We have to launch more than one interceptor.”
The batteries are coordinated at the field-commander level. Each of the batteries is independent, though they communicate with each other. If one goes down, the others can fill in, but that scenario is unlikely. “The systems have extraordinary backup,” he said. “It’s rare for a system not to be in complete working order.”
Iron Dome isn’t influenced by weather conditions. And good news for residents of Tel Aviv and farther north: the greater the distance, the better the interception ability.
“The more time we have, the greater the precision,” says Barak. “So Gush Dan [the central region where Tel Aviv is located] can be less afraid. Of course, many parameters must be considered, but in terms of this particular aspect, Gush Dan is easier for us than Sderot.”
Iron Dome uses a very sophisticated algorithm to plan the interceptor’s path, says Rafael. Once the operator presses “confirm,” the system does the optimization and decides when to launch the interceptor. After the launch, the interceptor receives ongoing updates about the target’s location, which it uses to tweak its trajectory so it can reach the optimal interception point.
One of the considerations is whether to intercept the target inside a protected area. Even if the interception can only be done over a populated area, aerial interception is still considered the better alternative. If the target lands in a protected area, there will be a lot more damage than if it is intercepted and a piece of metal falls that can’t cause as much damage.
“Our goal is to reduce the loss of life, to improve the home front’s ability to withstand [the rockets], and we build our forces to that purpose. We understand that with selective, personal warning, we will limit the number of casualties and the amount of damage of the rockets,” said Lt. Col. Gil – whose last name cannot be published – the head of the command, control, communications and warning department in the IDF. “So, if we measure the number of injuries per rocket, we’ve seen a reduction since the Second Lebanon War [in 2006]. Also in the measurement of damage to the economy, which cost hundreds of millions of shekels a day during the war, the goal is to reach a level of a tenth of that, and even less.”
Gil explains that there are a number of sensors, and not just the Iron Dome radar, that identify a rocket launched at Israel. All the information from these sensors is collected by a single system operated by the air force, which then draws a prediction of an elliptical area where the missile is expected to land. The farther and longer the missile flies, the smaller the ellipse. This information is then passed onto a second command and control network belonging to the Home Front Command. This system maps the ellipse onto what are called “polygons,” 235 of which cover the entire country. The IDF then alerts the residents of the relevant “polygon” areas where the missile is forecast to fall – and only them.
That marks a great improvement in fine-tuning threats so as few people as necessary take shelter and disrupt their routine. Israel used to be divided into only 10 regions for missile-warning alerts, and as recently as a year and a half ago there were just 147 regions, said Gil.
This feature will eventually be enhanced by the 388 million shekel ($113.8 million) National Message system – a major Home Front Command project being developed to provide area-specific rocket warnings to civilians by cellphone and other means, not only via sirens. Only parts of the system are complete and operational. The goal is to provide alerts to people in a specific polygon of an impending attack, although it will be possible to also receive warnings of other areas, such as where a user’s parents or children are.