Why the Navy's Laser Weapon Can Blind a Drone but Can't Handle a Cloudy Day

The pitch sounds almost too good to be true: a weapon that fires at the speed of light, costs roughly a dollar per shot, and never runs out of ammunition as long as the ship has power. No missiles to restock mid-deployment. No $3 million interceptor chasing a $500 drone. Just a focused beam of photons doing what physics says they should do.

Photo by Amar Preciado on Pexels.

So why isn't every destroyer in the fleet already bristling with laser turrets? Because the ocean, it turns out, is one of the worst possible places to shoot a laser.

What the Navy Actually Has

The Laser Weapon System Demonstrator, branded LWSD, because the Pentagon cannot resist an acronym, has been operational aboard USS Portland since 2021. It's a 150-kilowatt solid-state laser, and by all accounts it works. During tests in the Pacific, it disabled unmanned aerial vehicles and small boat targets without so much as a recoil. The Navy has also been testing the High Energy Laser with Integrated Optical-Dazzler and Surveillance system, or HELIOS, on USS Preble. Same basic promise, more integrated fire control.

Both systems are real. Both systems shoot things. Neither system is scheduled for fleet-wide deployment anytime soon, and the reasons why tell you almost everything about the gap between a promising demo and a warfighting capability.

The Atmosphere Is Not Your Friend

Here's the problem nobody puts in the press release: a laser beam passing through air isn't passing through nothing. It's passing through humidity, salt spray, aerosols, rain, fog, and, on a bad day near the waterline, a thermal layer that bends the beam like a funhouse mirror.

This phenomenon is called atmospheric attenuation, and it matters enormously. At 150 kilowatts in clean, dry air at altitude, you have a serious weapon. At 150 kilowatts in a humid Persian Gulf morning with sea spray kicking off three-foot swells, you have a very expensive flashlight.

The military calls the problem "thermal blooming" when the beam heats the air it travels through, causing the beam to defocus and spread. The more powerful the laser, the worse the blooming. It's one of the more ironic failure modes in weapons history, a laser so powerful it defeats itself.

graph TD
    A[Laser Fires] --> B{Atmospheric Conditions?}
    B --> C[Clear & Dry]
    B --> D[Humid / Foggy / Salty]
    C --> E[Target Engagement]
    D --> F[Beam Scatter & Defocus]
    F --> G[Reduced or Zero Effect on Target]

The Scaling Problem

Defense contractors will tell you the solution is more power. Get to 300 kilowatts, 500 kilowatts, a megawatt, and you punch through the atmosphere's interference with enough energy left over to matter.

That argument is not wrong. It's just incomplete.

More powerful lasers need more electricity. More electricity means bigger generators, which means bigger ships or significant redesigns of existing ones. A Burke-class destroyer wasn't built with a megawatt laser in mind; its power plant was designed around its current weapons suite, radar systems, and propulsion. Retrofitting that electrical infrastructure isn't a software update. It's a shipyard project.

And then there's heat. High-energy lasers are not efficient, the best solid-state systems convert roughly 30-40% of input power into laser output. The rest becomes heat. Managing that thermal load on a steel ship surrounded by corrosive saltwater, without degrading the beam optics or cooking adjacent electronics, is a serious engineering challenge that doesn't get nearly enough attention in the brochures.

Where It Actually Makes Sense Right Now

None of this means directed energy is hype. It means it's a maturing technology being asked to grow up faster than physics prefers.

For specific missions, countering slow UAVs, dazzling surveillance drones, disabling small surface threats at short range in favorable conditions, shipboard lasers are genuinely useful today. The cost-per-engagement argument is real and it matters more every year as cheap drone swarms become a credible threat to expensive surface combatants.

The honest version of the story is this: laser weapons work when everything cooperates. The weather, the range, the target type, the power supply. What the Navy is still working out is how to make them work when things don't cooperate, which is most of combat.

Until then, the destroyers keep their missile magazines stocked. A dollar per shot is a fantastic deal. Getting that shot to actually arrive is the part that still costs extra.