Separately, in May 2017 the Army tested a five-kilowatt drone-killing laser mounted on an eight-wheeled Stryker armored personnel carrier in an air-defense trial at Fort Sill. The mobile armored laser shot down twenty-one of twenty-three drone targets in what was billed as a realistic exercise. A powered-up ten-kilowatt version, with greater range and hitting power, will be tested in November.

On June 26 an Apache helicopter successfully tested a high-energy laser pod on targets at the White Sands testing range in New Mexico—the first laser weapon ever employed by a helicopter.

(This first appeared last year.)

As much as laser-armed helicopters might seem like they belong in a Command & Conquer video game, in reality they are joining a wide variety of ground-, air- and sea-based laser platforms—many of which may be entering service in the coming decades and a few of which are already operational. In fact, a new era of laser warfare may soon be dawning, thanks to lasers’ usefulness for countering two important weapons systems: drones and long-range missiles.

Films like Star Wars depict laser weapons as emitting short pulses of green and red light. However, the “phasers” depicted in Star Trek in the 1960s were arguably a bit more accurate. Real laser weapons project a coherent ray of directed photons (light) that strike their target virtually instantaneously. This beam often streams into the target for several seconds or longer as thermal energy builds up to destructive effect—although some “pulsing” lasers also exist.

However, unlike the weapons in Star Trek, the rays from high-energy antimaterial lasers for use in the atmosphere are silent and generally invisible, as they usually operate at an optical wavelength indiscernible to the human eye. And today’s laser weapons are more likely to burn a hole in a target or cause it to combust, rather than vaporizing it.

Why use a laser instead of a bullet, shell or missile? To begin with, lasers are highly accurate and quick acting, since they are fast as light and mostly unaffected by gravity. This could make them ideal for swatting down small, speedy targets, such as incoming rockets and artillery shells. Laser precision could also be handy for disabling ground or sea vehicles without killing their occupants. Of course, a soundless, invisible and recoilless weapon is also pretty stealthy—if you can get close enough to use it.

Most importantly, lasers could be very cheap. Contemporary missile-defense systems, such as Israel’s Iron Dome or the United States’ GMD antiballistic missile system, are much more expensive than the missiles they are designed to shoot down, making them untenable were they to face mass attacks. The same problem exists at the tactical level when considering how to counter the future threat of weaponized drone swarms: basically large flocks of small, expendable drones designed to overwhelm enemy defenses. While antiaircraft missiles may cost hundreds of thousands of dollars—or millions for antiballistic missile interceptors—the energy consumed by a laser weapon might cost as little as a dollar. For systems hooked up to a power generator, the “ammunition supply” could be virtually unlimited.

However, lasers do come with disadvantages that have held back their adoption for decades. To start with, laser energy tends to “bloom” or diffuse in an atmosphere, limiting maximum range—especially when obstructed by sand, smoke or fog. In fact, the relative lack of obstructive particles in space explains why they are considered ideal space-based weapons.

Furthermore, lasers may have difficulty burning through denser materials, and often require several seconds of continuous contact to inflict significant damage—which may not be enough time to disable heavier projectiles, depending on the power and engagement range of the laser as well as the speed of the target. In fact, development of laser-resistant materials and countermeasures has proceeded apace despite lasers having yet to enter widespread operational use.

Another consideration is that lasers create virtually no kinetic “pushback,” so if a laser can’t burn out a critical component on a vehicle or munition—such as a warhead, engine, heat shield, targeting system, or fuel supply—it may fail to stop the target from hitting friendly forces.

Finally, laser weapons require powerful electrical generators or dangerously volatile chemical fuels, as well as bulky liquid or solid-state cooling systems. These limitations pose serious obstacles to producing field-deployable lasers. However, recent advances in solid-state laser technology may offer a solution to limiting the size of the power supply, though they do require additional cooling measures.

There are also legal restrictions: the 1995 Protocol On Blinding Laser Weapons—part of the U.N. Convention on Certain Conventional Weapons—forbids the use of “dazzler” lasers explicitly designed to permanently blind the eyesight of adversaries. This came into force after several dazzler lasers were developed and even exported and possibly used, and it is rumored the Chinese Type 99 tank may still have such a weapon system despite the protocol.

Fortunately, the protocol appears to have been more broadly interpreted as discouraging the use of lasers as an explicitly antipersonnel weapon. However, it does not restrict the use of lasers against manned vehicles.

Indeed, lasers might be practical for disabling small ground vehicles, attack boats and aircraft. However, the majority of contemporary lasers are designed as defensive weapons to counter drones and enemy missiles and shells.

Indeed, the first laser weapon to see operational use in a combat zone, the Zeus-Humvee Laser Ordnance Neutralization System, was employed by the U.S. Army to safely detonate roadside bombs and unexploded ordnance in Afghanistan and Iraq. Using the solid-state lasers with a range of up to three hundred meters was considered a safer alternative to manually rigging C4 next to the deadly explosives. You can see a video of the Humvee-mounted laser taking out unexploded ordnance starting at 5:43 in this video.

Another laser that has entered operational use is the unimaginatively named AN/SEQ-3 Laser Weapon System, a thirty-three-kilowatt array of six solid-state lasers that proved so successful when tested onboard USS Ponce that the Navy decided to keep the weapon on the amphibious transport after the trials were complete.

Naval vessels may be an ideal platform for lasers, as they can more easily feed them power via their onboard electrical systems. Furthermore, warships desperately need close-defense weapons to protect against high-speed antiship missiles, such as the BrahMos cruise missile. Naval lasers also have application against swarming drones and high-speed motorboats, and could even be useful for delivering nonlethal warning shots, or disabling specific components of a vessel without sinking it. You can see a laser mounted on the Ponce engaging a motor boat and an aerial drone in this video.

The Navy hopes to develop sixty- to one-hundred-kilowatt lasers with greater range and power for use on its Arleigh Burke–class destroyers and Littoral Combat Ships. A full-power hundred-kilowatt Free Electron Laser is slated for testing in 2018, and might see use on the Navy’s new Zumwalt-class stealth destroyers.

Numerous other laser projects have failed to produce viable systems over the years. One of the most infamous was the billion-dollar Airborne Laser System, a chemically fueled megawatt-class laser mounted on the nose of a Boeing 747 jumbo jet designated the YAL-1. Smaller tracking lasers helped aim the huge weapon, which could fire twenty to forty pulses lasting three to five seconds each. The ABL successfully destroyed two tactical ballistic missiles during tests in 2010, which you can see in this video.

However, the Air Force ultimately scrapped the program because of the ABL’s impractical range limitations: the jumbo jets would have had to enter hostile airspace close to the launch sites to have a chance at downing the missiles in the takeoff phase. However, in 2015 the Air Force announced it was looking into installing longer-range airborne lasers on drones instead, with a prototype slated to begin testing in 2021.

In 2009, the U.S. Air Force also test fired the hundred-kilowatt Advanced Tactical Laser for use in destroying ground targets onboard its legendary AC-130 Spectre gunship, using it to burn out a truck’s engine block. The enormous weapon might also be a useful way to discreetly incinerate strategic material targets, although the potential cloak-and-dagger aspect has raised some ethical concerns. Although the ATL laser was not approved for operational use, the Air Force Special Operations Command still would like to equip its AC-130s with directed energy weapons.

The Air Force is currently focusing on a 150-kilowatt system called the High Energy Liquid Laser Air Defense System, which combines liquid cooling with solid-state laser technology. HELLADS could be employed on a turret mount by a variety of platforms, including fighter jets, Reaper drones and even aerial-refueling tankers. The scalable laser, which could be become operational as soon as 2023, is intended to shoot down incoming air-to-air missiles and drones, although it could also have applications against ground targets and manned aircraft.

The U.S. Army has long been interested in using lasers to shoot down incoming rocket and mortar shells, a mission known as Counter-RAM. Considering how even the best-equipped and -trained soldiers are vulnerable to bombardment from old and widely available Katyusha rockets and portable eighty-two-millimeter mortars, an affordable means to shoot down these projectiles could save lives on exposed forward operating bases, civilian communities and vulnerable fixed installations in the Middle East and Afghanistan.