Ukraine has received 108 Krab self-propelled howitzers from Poland. In three years of hard fighting since the first of the 53-ton, five-person guns arrived in Ukraine, Ukrainian forces have lost no fewer than 35 of the howitzers, which fire Ukraine’s best 155-millimeter shells as far as 31 km.

On or just before 7 June, a Russian drone crew showed what happens when artillery gunners don’t take every precaution. The Russian crew flew two fiber-optic first-person-view drones through gaps in the front and back of one Krab’s covered, concealed dugout in a tree line somewhere along the 1,100-km front line—and lit the gun on fire, destroying it.

It’s probably the 36th Krab loss. And it was totally preventable. 

Tiny FPV drones weighing a few pounds and clutching small warheads have, for two years now, hounded troops and vehicles on both sides of Russia’s 40-month wider war on Ukraine. For most of those two years, however, the drones’ prey were fairly safe inside or under loose concealment. 

After all, almost all FPVs were, until recently, controlled via wireless radio—and radio signals can’t always penetrate wood, brick and metal. At the very least, structures limit how far a drone can fly. “Obstacles between your transmitter and receiver can significantly reduce range,” FPV expert Oscar Liang explained.

The proliferation of fiber-optic drones has changed everything. Controlled via signals that travel up and down miles-long, millimeters-thick optical fiber, these FPVs are largely unbothered by buildings and dugouts—as long as their operators can avoid snagging the fibers and find some way into the covered position: an open door or window, a gap between layers of camouflage netting.

Which explains the new genre of drone video from the front line of the wider war: indoor drone strikes. FPVs are slipping through open doors and past dangling tarps and nets to strike soldiers and vehicles hiding inside what were once safe havens from FPV raids.

Knock knock

A dramatic video of one indoor strike, carried out by the Ukrainian Unmanned Systems Forces’ Birds of Magyar unit in April, is typical of the new genre. Easing inside a warehouse, maneuvering past one parked Russian vehicle to take aim at a BMP fighting vehicle with its back hatch ajar, the drone struck inside the BMP.

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The explosion ignited a blaze that may have spread throughout the warehouse, if footage from an overhead surveillance drone is any indication. It’s possible one drone costing less than $1,000 destroyed several vehicles.

“Magyar birds are looking for worm equipment in the corners where the enemy definitely doesn’t expect the FPV drone,” someone—presumably Robert Brovdi, then Magyar’s leader and now the head of the USF—narrated over footage of the strike.

The Ukrainian Krab crew clearly also didn’t expect Russian FPVs to come snooping, which may explain why they accidentally left entrances for the maneuverable drones.

The Krab’s bulk—typical of all self-propelled guns, or SPGs—makes it hard to cover and conceal with 100% certainty. According to analyst Andrew Perpetua, it may actually be easier to dig an effective hideout for a towed gun. 

And it’s not like SPGs are actually rolling around the battlefield the way they may have done in previous wars. Tiny drones have made it virtual suicide for an artillery crews to “shoot and scoot.” So they don’t need tracks. They don’t need to be self-propelled.

“Instead of investing gajillions of dollars developing crappy SPGs that barely carry any ammo and often weigh obscene amounts of tons but can ‘shoot and scoot,’ countries should be investing in ultra lightweight, long-range towed guns that specialize in push and bush,” Perpetua wrote.

That is, push into position, hide in the bushes—and stay there. The gunners just need to work much harder to completely cover their guns when they’re not actually shooting at the enemy.

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Surprisingly, Russian soldiers used scissors to down a Ukrainian fiber-optic drone — but Kyiv also knows a trick or two

On or before Saturday, Russian troops somewhere along the 700-mile (about 1,100-km) front line of Russia’s 40-month wider war on Ukraine detected incoming Ukrainian drones. Specifically: fiber-optic first-person-view drones that send and receive signals via millimeters-thick, but miles-long, spools of optical fiber.

Fiber-optic FPVs are extremely difficult to defeat. The main defense against wireless FPVs, which send and receive signals by radio, is electronic jamming that can ground the drones before they strike. But fiber-optic FPVs can’t be jammed. That’s why both the Russian and Ukrainian armed forces are building more of the fiber-optic models—even though they’re several times more expensive than the $500 wireless models.

But sever a drone’s optical fiber, and it’ll fall from the air. Optical fiber is tough, but it can be broken by bending it 180 degrees. Surgical scissors can also cut right through it—as the Russians were well aware. “Got the scissors?” one hidden Russian asked after a Ukrainian FPV buzzed past, trailing its optical fiber, in a video from the Saturday incident. “Got ‘em,” another hidden Russian responded.

The soldiers hurried from their hiding spot, found the drone’s thin optical fiber—and cut it.

The drone lost its command signal. “It’s falling,” one Russian breathed right before the drone exploded a short distance away.

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The circumstances of the Saturday fiber-cutting will be difficult for the Russians—and Ukrainians, for that matter—to duplicate. The soldiers had to have ample warning of the incoming drone raid, opportunity to hide from the passing drone and plenty of luck. If a second drone had followed the first, it might’ve struck the Russians as they tried to scissor the first drone’s fiber.

Cut the cord

Yes, scissors are an effective defense against fiber-optic drones—but only in the most extraordinary circumstances. That’s why both sides are literally digging in, going underground to avoid the millions of FPVs swarming the front as the war grinds into its fourth year.

More and more, armored vehicles and infantry hide indoors or underground when they’re not actively attacking or defending. It’s a new “era of the cautious tank,” according to David Kirichenko, an analyst with the Center for European Policy Analysis in Washington, D.C. 

The only scalable active defenses against fiber-optic drones are to shoot them down right before they strike, usually with shotguns. That’s risky, however. Miss with your first shot, and you might not get a second one before the drone strikes.

Acknowledging the difficulty of stopping fiber-optic FPVs right before they explode, the Russians and Ukrainians are trying to stop them “left of the boom,” to borrow a US Army term. That might mean detecting the optical fibers left over from earlier attacks, tracing the fibers back to the drone operators—and bombarding the operators with drones or artillery. 

That only works if the operators unwisely linger in the same location long enough for the enemy to hunt them down. 

Ukrainian forces are trying to get even farther left of the boom—attacking the factories that produce Russia’s FPVs. 

On 13 March, long-range drones belonging to the Ukrainian defense intelligence agency struck a hidden drone manufacturing facility in Obukhovo, just outside Moscow, 300 miles (about 480 km) from the border with Ukraine. A few weeks later, in April, Ukraine sortied one of its then-new Aeroprakt A-22 sport plane drones to strike a drone plant in Yelabuga, 550 miles (about 880 km) east of Moscow.

And on 4 April, a dozen Ukrainian attack drones motored 460 miles (about 740 km) into Russia and struck a factory in the city of Saransk. The target was the Optic Fiber Systems factory, which produces—you guessed it—fiber-optic cables. The critical component in Russia’s best unjammable FPVs.

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