FOR EVERY ten incoming rockets, Israel’s system of defensive mobile batteries, the Iron Dome, typically shoots down nine. Israel claims to have maintained that ratio even as Hamas has fired bigger salvoes from Gaza in the aftermath of the Islamist group’s attack on Israel on October 7th. However, Iron Dome has limitations. Chiefly, replenishing interceptor stocks, even with American manufacturing help, is pricey. Reported costs for a single interceptor, called Tamir, range from $40,000 to more than double that. Israel thus plans to deploy laser air defences. It would be the first country to set up such a system. How does Iron Beam, as the system has been dubbed, actually work?
Israel’s defence ministry decided to build out Iron Beam last year after it destroyed rockets, mortars, drones and anti-tank rounds in tests. As Naftali Bennett, then prime minister, put it, Israel would erect a “laser wall”. Operations were expected to begin in perhaps 2025. Now, with war raging, the timeline is being crunched. The big selling-point, says Uzi Rubin, a former head of the defence ministry’s Israel Missile Defence Organisation, is Iron Beam’s unlimited magazine. Laser shots are “manufactured on the run”, he notes, each with a few dollars’ worth of diesel in an electricity generator.
Iron Beam is a technological marvel. The mobile laser guns use a complex configuration of mirrors to redirect photons from light-emitting diodes into a single beam. To prevent the mirrors from melting, they were designed with exceptional reflectivity and cooling systems. After 10km of travel, an Iron Beam laser reportedly has the diameter of a coin and is stunningly precise, despite the distorting effects of wind and air temperatures.
But however fearsome Iron Beam’s 100-kilowatt (kW) lasers, Dr Rubin cautions that widespread expectations of “Star Wars performance” are unrealistic. Experts reckon that Iron Beam’s range, at best, will be just over a third that of Tamir interceptors, which can hit targets even 70km away. The system’s state-owned Israeli developer, Rafael, has spoken of a range of “several miles”. One constraint is that weather can affect the system—moisture and particles, like smoke, absorb laser energy.
Another drawback is “dwell time”. It takes several seconds of contact for an Iron Beam laser to pump enough energy into a spinning rocket for it to break apart or explode. An Iron Beam gun will therefore be unable to parry a heavy barrage, so the system will be used alongside Iron Dome, which fires interceptor volleys rapidly. Iron Beam will also draw targeting data from Iron Dome’s network of radars and fast computers. And the new system’s lasers might be best suited to fighting slower attack drones, which do not spin and rely on relatively delicate rotors, wing flaps and guidance systems, so they can be shot down with briefer laser blasts.
One worry is that Hamas and other militant groups might manage to sheath rockets in a heat-resistant material. And the set-up cost of Iron Beam’s batteries is considerable (though not disclosed). Yaakov Amidror, a retired major general and former head of Israel’s National Security Council, says that it remains to be seen whether Iron Beam shoots down enough rockets to justify the investment.
Other laser air defences are in the pipeline. Lockheed Martin signed, in December 2022, a deal with Rafael to jointly develop a variant of Iron Beam for America’s forces and, potentially, their allies. The US Air Force Research Lab’s “directed energy” team in Albuquerque, New Mexico, is developing 300kW-class lasers to defeat what wargaming suggests could otherwise become “overwhelming salvoes” of missiles, according to Nicholas Morley, a senior scientist at the lab.■
