A directed energy weapon can theoretically defend against drone swarms and massive numbers of cheap rockets.
Modern warfare, such as that being conducted in Ukraine, has precipitated a predicament long in the making. As offensive weapons become more accessible and grow more numerous, does it make sense to defend against them with sophisticated—and very expensive—countermeasures? Take for example, shooting down an armed or kamikaze drone with a Patriot missile. The drone can be bought for a few hundred dollars, whereas the Patriot missile costs $4 million. Which side won?
A swarm of 54 drones flew toward Kyiv last month in the biggest drone attack of the war to date. An incredible 96 percent of them were shot down by Ukraine’s air defense using what has been described as a “dog’s breakfast” of defensive countermeasures that include manually sighted antiaircraft guns, shoulder fired Stinger missiles and Patriot missiles on mobile launchers.
Israel guards against enemy aircraft with Iron Dome, perhaps the world’s best air defense system, which uses interceptor missiles to take down anything from a fixed-wing aircraft to an artillery shell. Each Iron Dome battery is said to cost $50 million and each interception, $100,000 to $150,000.
Realizing that Iron Dome could be overwhelmed by unsophisticated weapons in large numbers (like a drone swarm), Israel would like to complement Iron Dome with Iron Beam, a 100 kW fiber laser weapon.
Iron Beam detractors say the system is only effective in good weather and at close range (due to laser beams losing their cohesiveness, and therefore their energy, after striking gas molecules in the atmosphere).
The obvious fix is to boost the power.
The U.S., which has pledged to support Israel in its defense and development of Iron Beam, has two 300 kW fiber laser systems being developed that emit 200 kW of optical power.
Russia has claimed to have used a laser weapon against Ukrainian drones but that has been refuted by Ukraine.
Why Ray Guns Make Sense
Ray gun advantages are as follows:
- A line of sight = path of ray—unlike a bullet, which takes a parabolic path due to gravity. There is no sight adjustment.
- It can be directed quicker than a wink. A laser can be directed by mirrors, as is done in LiDAR devices. Military lasers are more substantial than LiDAR systems and swivel on turrets, but the turrets are far smaller than those that fire ammunition. With little mass to move, the beam can move quickly to stay on target or lock on to other targets.
- No ammunition is needed and the cost of power is relatively cheap. The cost of a “shot” would be between about $2 for an Iron Dome and between $5 and $10 for a 300 kW laser, according to Michael Perry, VP at General Dynamics, who was quoted in IEEE Spectrum.
And so, the tables (or should I say the turrets?) have turned. The low-cost attacking aircraft can be brought down with an even lower-cost laser shot. In the extreme, a high-cost threat, such as a hypersonic missile, could theoretically be shot down for the cost of a burrito. That’s enough to make military mouths water.
Shoot Down a Bullet with a Bullet—Good Luck with That
Antiaircraft and antimissile defenses have relied on interception and knockdown using bullets or missiles. With the offense getting faster projectiles, culminating in the hypersonic or ballistic missile, capable of Mach 5 speed or greater, hitting them in flight is as likely as shooting a bullet with a bullet—in other words, practically impossible. So proved the Myth Busters, busting a favorite myth of Civil War battlefield combers for whom two bullets fused together could be sold for a ridiculous sum.
The U.S. military increased the odds of hitting a fast-approaching missile, if not a bullet, with the Phalanx CIWS gun system. The Gatling-style gun turret of a Phalanx fires so many bullets that its makers claim to have made a protective “wall of lead.” However, the wall is quite porous and its lead quickly depleted.
Even if there is no hope of hitting a fast incoming missile, the military still believes in a blast that is close enough to either disable the missile control and guidance or a blast wave that can change the missile’s trajectory so it misses its target.
But tests have shown that even getting close enough cannot be guaranteed. It may be time to admit that when we had only bullets, our only hope of shooting down airborne threats was to improve the bullets. But now that directed energy weapons have started to show promise of a theoretically sure-fire land-to-air defense, it should be time to pour R&D into solving the remaining challenges of making ray guns a reality.
