June 9, 2023: The United States and Israel have resolved their differences over the use of two Iron Dome batteries the Americans purchased but were unable to use because Israel refused to provide source code for Iron Dome that the U.S. demanded based on claims that the U.S. needed it to integrate the system into American air defense networks. It took nearly three years for the Americans and Israelis to achieve a solution both found acceptable.

In 2020 the U.S. Army found itself in an embarrassing situation after spending a billion dollars to buy two Israel Iron Dome missile defense batteries. The problem was the army refused to put their Iron Dome systems into service because Israel refused to turn over the source code for the novel anti-rocket/mortar system. The army said it needed the source code in order to make Iron Dome part of the army air defense system. There is no such integrated system and, if there was, the source code was unnecessary as an API (Application Programming Interface) could link one system with others.

The army also expressed doubts about being able to use Iron Dome in other countries, like Iraq or Afghanistan, without source code. But Israel had sold dozens of Iron Dome batteries to export customers like Azerbaijan, Czech Republic, India, Romania and Singapore with possible sales to NATO, South Korea and (very discreetly) Saudi Arabia. The sale to the Czech Republic was contingent on Iron Dome being capable of integration into the NATO air defense system, which includes many different systems. That was done with an API. The sale to Singapore, like the possible (or already completed) sale to Saudi Arabia was handled confidentially so as not to anger nearby Moslem nations. Singapore has Malaysia and Indonesia to worry about and Saudi Arabia has a lot more potentially offended Moslem neighbors. Such sales are not entirely secret. Iron Dome cannot be disguised as something else and one Moslem nation, Azerbaijan, had already openly purchased Iron Dome with no ill diplomatic effects. The sale to the Czech Republic means Iron Dome would be “integrated” with nearby NATO nations who use American air defense systems.

U.S. Army officials protested that their situation was somehow different. There is some disagreement over how and why this situation is different. The U.S. Army has long been criticized for neglecting air defense. This was true and there were practical reasons for that attitude. The U.S. Air Force gained air dominance, which is one step up from “air superiority”, towards the end of World War II. Thus from 1945 to now, no one has been able to seriously damage U.S. ground forces from the air. American troops have suffered losses from airstrikes, but these were friendly fire incidents when air force jets were called in to provide close air support. Until the development of smart bombs such air support always involved some risk to the troops being supported. After the Cold War ended in 1991 American ground forces found themselves increasingly vulnerable to missile and rocket attacks. The “air domination” provided by American airpower was less effective against these and the army was increasingly pressured by the public (via Congress) to develop more effective defenses against this new threat from the air. The army procurement system has not got a great record in situations like this and is especially resistant to obtaining foreign systems, even ones like Iron Dome that have been combat proven and an obvious solution to a very real problems with defending American bases in Iraq, Afghanistan and elsewhere against the kind of weapons Iron Dome have proven it can handle.

The army, under pressure from Congress, said it would put the two Iron Dome systems into service. The Dome Batteries arrived in 2020 and a hundred or so soldiers were trained to operate the equipment. The army admitted that, if called on, their Iron Dome batteries, or at least one of them, could be ready to deploy before the end of 2020.

There is still the mystery over why the U.S. Army was so intent on trying to force Israel to turn over the source code. The U.S. successfully tested the Iron Dome systems it obtained earlier for evaluation. The Israelis point out that they have not shared Iron Dome source code (and a lot of other similar stuff) with anyone. In addition, the U.S. has been much less successful at keeping secrets than Israel. The U.S. Army is under pressure to use Iron Dome in places like Iraq where American bases are being hit with rockets fired by Iran-backed Iraqi militias. Israel even modified Iron Dome in 2016, at American request, so that it could also shoot down UAVs.

There was an American proposal to hold a competition to evaluate other systems that can do what Iron Dome does. The problem was that there are no other such systems and the Israelis rightly thought the U.S. army’s demand for the Iron Dome source code was only so the U.S. government and American defense contractors could reverse-engineer it and create a competing U.S. made system.

What makes Iron Dome unique, other than the fact that it works, is the use of two radars to quickly calculate the trajectory of the incoming rocket and do nothing if the rocket trajectory indicates it is going to land in an uninhabited area. But if the computers predict a rocket coming down in an inhabited area one (or often two to be sure) $50,000 Tamir guided missiles are fired to intercept the rocket. This and the fact that the Iron Dome fire control system can track hundreds of incoming missiles at once makes the system cost-effective. So far Iron Dome has shot down about 85 percent of the rockets it calculated were headed for populated areas. The Tamir missiles used by Iron Dome weigh 90 kg and have a range of 70 kilometers against rockets, mortar shells and artillery shells up to 155mm. Iron Dome can also shoot down aircraft and helicopters that are operating at up to 10 kilometers (32,000 feet) altitude. The Iron Dome software includes the capability to quickly integrate a new “map” that indicates areas that must be protected and other areas where the rocket or shell can be allowed to land harmlessly. Export customers have been satisfied with how this works. Some critics have cast doubt on the actual effectiveness of Iron Dome. Yet property and human losses plunged precipitously once Ir0n Dome was in service and the people being protected were satisfied.

There have been competing systems. In 2008, while Iron Dome was still being developed and several years away from entering service, Hamas in Gaza was increasing the number of rockets and mortar shells fired into southern Israel. At that point, several hundred rockets and mortar shells a month were fired into southern Israel. Many Israelis had noted that the Americans and British were already using an effective anti-rocket system; C-RAM. This is a modified version of the U.S. Navy Phalanx system, which was originally designed to protect warships from anti-ship missiles. As originally designed, you turned Phalanx on whenever the ship was likely to have an anti-ship missile fired at it. The Phalanx radar can spot incoming missiles out to about 5,000 meters, and the 20mm cannon is effective out to about 2,000 meters. With incoming missiles moving up to several hundred meters a second, you can see why Phalanx is set to automatic. There's not much time for human intervention, which is why the Phalanx has to be turned on and set to automatically detect and shoot at incoming missiles. But weapons engineers discovered that Phalanx could take out incoming 155mm artillery shells as well. This capability is what led to C-RAM. Israel considered buying C-RAM to provide some protection to towns on the Gaza border but decided against it because Iron Dome was close to being operational, which occurred in 2011.

Since 2003 there have been two major Phalanx mods. In one, the Phalanx was adapted for use on land, to shoot down incoming rockets. This was done by using a larger artillery spotting radar, which directs Phalanx to fire at incoming mortar shells and rockets. Not all the incoming stuff is hit, but nearly 80 percent of it is, and that is very useful. The second mod was for shipboard use, and changes the software so the Phalanx can be used against small boats, especially those of the suicide bomber variety.

In 2007 Britain bought a C-RAM system to protect its airbase in southern Iraq. A C-RAM Phalanx system, which can cover about four kilometers of border, costs $8 million and was effective in defending bases. What it could not do effectively was defend long borders Israel had to guard in the north (Lebanon and Syria) and south (Gaza).

C-RAM uses high explosive 20mm shells that detonate near the target, spraying it with fragments. By the time these fragments reach the ground, they are generally too small to injure anyone. At least that's been the experience in Iraq. The original Phalanx used 20 mm depleted uranium shells, to slice through incoming missiles. Phalanx fires shells at a rate of 75 per second. Another advantage of C-RAM is that it makes a distinctive noise when firing, warning people nearby that a mortar or rocket attack is underway, giving people an opportunity to duck inside if they are out and about.

The first C-RAM was sent to Iraq in late 2006, to protect the Iraq Green Zone, the large area in Baghdad turned into an American base. It was found that C-RAM could knock down 70-80 percent of the rockets and mortar shells fired within range of its cannon. Not bad, since it only took about a year to develop C-RAM. Meanwhile, another version, using a high-powered laser, instead of the 20mm gun, was in development but never achieved enough effectiveness to enter service. By 2008 there were nearly 900 Phalanx systems in use, including some on Israeli warships. Most have not gotten these software mods that enable the cannon to knock down rockets and shells, as well as incoming anti-ship missiles.

Since 2011, when Iron Dome entered service, Israel has made progress in developing Laser Dome, a shorter range (two kilometers) Iron Dome that uses laser beams instead of rockets. Laser Dome is meant to reinforce Iron Dome, not replace it. A longer range (over 100 kilometers) missile has been developed for Iron Dome that enables one battery to protect a larger area. Laser Dome would be used against key targets that might be subjected to an overwhelming attack by a hundred or more rockets at once. Iron Dome cannot launch enough missiles to defend against such an attack, but Laser Dome could handle it since it can fire far more laser beams in less time than Iron Dome can fire longer range missiles. Laser Dome turned into Iron Beam and was introduced in 2023, Iron Beam will enter service in 2025, as part of Iron Dome systems. Iron Beam has a range of up to ten kilometers, depending on how large the target is. Larger targets often require more than one dose of Iron Beam before they are disabled. Iron Bean does not run out of ammunition as long as its power supply keeps working. The fire control system enables Iron Beam to rapidly identify and hit targets.

The key to Iron Dome success is its software and U.S. insistence on having access to it is seen as proof of how essential, and valuable that software is. The Israelis insist on keeping it secret.