Killer Lasers Work, but Are They the Best Defense Against UAVs?

• lasers
• Boeing
• UAV
• weapons
• Pentagon
• Israel
• Iran
• military

Why UAVs Aren't Scary

When Boeing's Laser Avenger shot down an unmanned aerial vehicle (UAV) with a laser last week, the technological might—with focus on a one-kilowatt laser that replaced the Avenger's usual surface-to-air missiles—aimed at a small flying robot begs the question; Since when did flying robots become a threat to U.S. or allied forces? To date, the U.S. military has spent essentially zero time or money on the prospect of countering hostile UAVs. That's because the risk of that kind of attack isn't really there. "We haven't really seen a UAV threat so far," says Guy Ben-Ari, a senior fellow at the Center for Strategic and International Studies in Washington, D.C. "It seems a little far-fetched, because the existing countermeasures are far superior to the potential threats."

The most tangible threats to date have been the handful of Iranian-built Mirsad 1 drones operated by Hezbollah. The Lebanon-based terrorist group has claimed that the Mirsad 1's 9-ft-plus-wingspan UAV (putting it out of the Laser Avenger's class) can be loaded with 110 pounds of explosives, but the model has yet to inflict any casualties. In the summer of 2006, an Israeli fighter intercepted a Mirsad-1 entering Israel's airspace and destroyed it with an air-to-air missile. A seemingly more successful Mirsad mission from that same summer, a widely reported kamikaze attack on an Israeli warship, turned out to be a conventional strike using a Chinese-built missile.

If U.S. forces were to ever go up against Mirsads, the lesson is clear: Shoot them down like any other plane. If one is humming along on a suicide mission, the same duck-and-cover or interception tactics used for mortars and rockets would probably be effective against an object moving at a comparatively slow 80 mph. The same holds true for the more advanced UAVs supposedly in development in Russia and China. According to Ben-Ari, although those countries are pursuing drones approaching the size and performance of U.S. versions that carry missiles, "They're still 5 to 10 years away. And those are optimistic numbers." Even if a full-scale conventional shooting war were to develop, the air defense against Russian or Chinese UAVs would be familiar: Fire missiles and bullets at it until it crashes. In this case, being a robot isn't an advantage.

The Problem With Lasers

The utility of using a laser, instead of conventional weapons, is not entirely clear. Boeing claims that it avoids the telltale muzzle flash or smoke trail that could give away the Avenger's position, but the relatively low power of the beam severely limits the scenarios in which it would be useful. Its target must be flying low enough to negate cloud cover, close enough to rule out atmospheric disturbance (which can refract the beam), and slow enough for the laser to heat up a crucial flight element. Coincidentally, those are the same conditions that could provide a UAV with a clear view of the hulking missile battery mounted on the back of a parked Humvee.

Instead, the Laser Avenger's designated targets are among the smallest, lowest-flying UAVs. Responding by e-mail, the company would only describe the UAV that was shot down (as well as the kind of target it's designed to deal with) as a small UAV with about a 6-ft wingspan. That rules out the most dangerous UAVs—those that are large enough to carry missiles, like the U.S.'s MQ-1 Predator or MQ-9 Reaper.

Big Worries Over Tiny UAVs

That's not to say that UAVs will always be harmless. In fact, the biggest long-term drone threat might have little in common with today's remote missile strikes or high-altitude reconnaissance missions. "UAVs could be used asymmetrically, in ways we haven't even imagined," says Ben-Ari. "You could have something that's two generations behind our drones, but they're swarming with hundreds of UAVs at the same time. Or being used as crop dusters, to deliver chemicals or bioagents." Instead of building a fleet of multimillion dollar UAVs, insurgents or terrorists could buy radio-controlled choppers and planes—toys, essentially—in bulk. And when it comes to drone swarms, or models too small to be reliably picked up on radar or other sensors, the Pentagon is relatively unprepared. Troops could deploy traditional anti-helicopter weapons that spray the air with shrapnel or flechettes , or simply open fire with shotguns and rifles, but these aren't optimal tactics. The helicopter mines' acoustic sensors and radar systems could be spoofed by smaller, quieter UAVs. And pitting a 12-gauge against a flock of incoming drones is a better plan in a video game than in real life.

That is where the Laser Avenger might just save the day. Forget the kilowatt-class laser; the system features tracking algorithms that are specifically designed to spot and zoom in on small UAVs. If Boeing's UAV-hunting capability was combined with sufficient firepower, the war with tomorrow's suicidal microrobot hordes could be over before it even begins.

4. RE: Killer Lasers Work, but Are They the Best Defense Against UAVs?
Against a swarm of radio control toys used for terrorism a better defense would be just radio interference to cut them from their controllers. The only use that I could think for this kind of laser would be as a sniper to eliminate a high value target like an important terrorist hiding among civilians with minimal collateral damage. Maybe Israel would be interested on this development.

3. RE: Killer Lasers Work, but Are They the Best Defense Against UAVs?
This program is likely part of a larger RDT&E; effort. Today, smaller UAV; tomorrow bombers taking off from enemy runways.

2. RE: Killer Lasers Work, but Are They the Best Defense Against UAVs?
Everybody forgets what I once read somewhere-lasers powerful enough to fry a UAV would be dangerous to people on the ground from reflected laser light powerful enough to cause instant blindness.

1. RE: Killer Lasers Work, but Are They the Best Defense Against UAVs?
A minor advantage would be the reduction in incidental damage. There wouldn't be any missing rounds coming down miles away.

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