Why are engineers pulling ropes into the sky again?
In the 2020s, engineers returned to an idea that was last seriously discussed in the 1940s: stretch something across the plane's path and let it fly into it. No electronics, no explosives, no expensive missilesThe idea is so simple that it's embarrassing to look at after seven decades of jet aviation, guidance systems, and network-centric warfare. And yet, it works again—because a multimillion-dollar missile versus drone for several thousand it doesn't add up well to the arithmetic of war.
Expensive rocket versus cheap drone
When the first series of Houthi UAVs began operating in the Red Sea in 2023–2024 Samad (Samad) and its accompanying anti-ship missiles, a problem previously discussed mainly at conferences has emerged. The attack vehicle is assembled from commercial components and costs as much as a used car. The interceptor missile costs as much as a small house. With a one-to-one ratio, the defense goes broke faster than the offense can go over budget.
Open-source figures vary, but the pattern is consistent: each interception of a cheap aerial target cost the defending side two to three orders of magnitude more than the target itself. Furthermore, a ship's missile supply is finite, while its drone assembly line is not. This gave rise to a question that had previously seemed academic: how to shoot down a flying moped without the economy eating away at the defense before the enemy does.
The question is actually an old one. Military technology has known several eras when a cheap, mass-scale threat defeated expensive, individual defenses, and engineers had to come up with a response from available materials.
Bolo, nets, and ropes: how they caught flying fish before drones
The oldest idea at work here is the bolo (or bolas) of South American shepherds: two or three weights, tied together with a rope, are thrown in a spinning motion and wrapped around the animal's legs. The principle is straightforward: not to hit, but to immobilize. It is this analogy that modern developers refer to, and for good reason: everything that comes next replicates the same mechanics in one form or another.
The first mass-produced “tackle against expensive threats” appeared on navy — anti-torpedo nets used on battleships and ironclads at the turn of the 19th and 20th centuries. A ship at anchor would lower steel nets along its sides using specially designed launchers. A torpedo from the Russo-Japanese War would get stuck in the net before reaching the side or explode at a safe distance. Cheap, crude, and effective, as long as the torpedo remained slow.
The battleship (battleship) of the Russian Imperial Navy "Evstafiy" was equipped with anti-torpedo nets, which are visible along the side in the photograph.
The same logic was repeated in the air in the 1930s and 1940s. Barrage balloons over London, Moscow, and Leningrad carried steel cables—an obstacle in the altitude zone where dive bombers and low-altitude bombers operated. An aircraft that struck a cable with its wing would, at best, be damaged; at worst, it would lose control. artillery finished off the rest.
A balloon apron used for the air defence of London during World War I.
The British went further than anyone else. In 1940, they developed the PAC— Parachute and Cable ("Parachute and Cable"). The system fired a cable vertically upward, carrying a parachute and a small mine at the end. A dive bomber, snagging the cable with its wing, pulled it along; the parachute opened, the mine was pulled in, and detonated. Conceptually, this is today's KIT chain, only on a one-to-one scale and with a warhead at the end. With the advent of jet aviation, the idea faded into obscurity: planes began flying too high and too fast to be caught by the taut line. For eighty years, it was barely remembered.
KIT: A chain instead of a rocket
The return happened in Germany. Karlsruher Institute for Technology (Karlsruhe Institute of Technology) is a major research center formed in 2009 by the merger of the University of Karlsruhe and the national research center Research Center Karlsruhe (Karlsruhe Research Center) presented a setup that fires thin metal chains at an approaching drone. According to open source reports from 2024–2025, the chains are approximately three to four millimeters thick.
Now things get interesting, and it's important to distinguish between two different mechanisms. The first is rotor capture. A chain link catches on a propeller blade, the instantaneous rotation wraps the remaining chain around the motor shaft, and the propeller locks. For a single-rotor aircraft, this immediately results in a loss of thrust. For a quadcopter, it means a loss of control: the three remaining motors can't compensate for the asymmetry, and the aircraft collapses. The second mechanism is frame entanglement. A long chain wraps around the arms and the frame, simultaneously catching several propellers and preventing the electronics from stabilizing the aircraft. In practice, both effects often work together, and which one is triggered is irrelevant in a falling drone.
The chain is crucial, not a rope or a solid object with weights. A rope slips and breaks; a solid object produces a pinpoint impact, which the quadcopter, with luck, survives. A chain combines flexibility and weight, and has links that almost guarantee the blade will catch.
The authors have not yet disclosed the details of the tests. Publications indicate that computer modeling was followed by a full-scale testing phase, and that the developers plan to expand field testing. The precise parameters of the system, including its range, projectile velocity, and launcher type, have not been publicly disclosed. This is an early stage of the project, not a production product; all that can be said about combat effectiveness so far is simply "the concept works." To the developers' credit, they themselves are not promising a universal solution: the chain system is designed for close-range combat, against low-flying commercial and home-grown drones. This is its niche, and it's a small one.
Niche Neighbors: What Else is Used to Catch Drones?
The KIT chain isn't the only return to an old idea. The Russian protective-capture network "Darwin", introduced in 2024, operates on a similar logic, but in a stationary configuration. Its cells are designed for two-stage operation: first, they expand to approximately double their original size, absorbing the impact energy, and then they hold the drone as a rigid structure. The key is to catch the drone before its warhead detonates, rather than destroying it along with itself. The manufacturer claims that a single net is capable of detaining a mid-range drone.
The weak point is obvious and common to all mechanical defenses: the network is stationary and disposable within the impact zone. A breached cell is an open door for the next drone. Therefore, the Darwin shield makes sense not as a point shield, but as a perimeter around an object, designed for hit statistics rather than a single interception. A chain launcher, by contrast, is an expendable projectile, not an expendable perimeter section; these are different tactical roles, with the overall goal of "catch, not destroy."
In parallel, UAV interceptors with suspended nets and cables, conventional nets on tripwires over vehicles and positions, and infantry equipped with shotguns are operating. This is all the low-level engineering that has grown out of practice in the Eastern European theater in recent years: from factory designs to homemade garage creations.
The "classic" answer to the same question is small-caliber anti-aircraft artillery with programmable projectile detonation. Family Bushmaster Northrop Grumman's Bushmaster, chambered in 25mm and 30mm, reliably targets drones within a radius of several kilometers. But the projectile, with its programmable fuse, costs as much as a good smartphone, and the chain costs as much as scrap metal from a warehouse. With a large number of targets, the cost gap quickly adds up.
All mechanical solutions have a common limit: altitude. Nets, chains, and cables work only where they can be physically extended; against a drone flying at an altitude of two kilometers and the speed of a jet, they are useless. Miracle-weapons It doesn't work from this branch, and none of the developers claim it.
Where is this place in defense?
The chain system is not a replacement Defense, and its lowest and cheapest floor. Its natural location is the outer perimeter of the protected facility: an oil depot, a warehouse, a command post, a bridge. Where it can reach not a Kalibr missile or a cruise missile, but a commercial quadcopter with a gimbal or a homemade kamikaze craft.
Alongside chains, other low-cost solutions are also exploring the same niche. In February 2026, a German company announced DroneHammer (The "Hammer for Drones") is a small laser-guided missile costing around 2500 euros and with a claimed range of approximately two kilometers; production prototypes are promised by the end of 2026. There are many approaches, and this is normal for the early stages: no one yet knows which solution will be widely adopted.
It's expected that in the next few years, the lower reaches of anti-drone defense will be filled with precisely these types of devices—simple, inexpensive, and easily repaired. The cables that were strung over London eighty years ago have become shorter, thinner, and more flexible in the 2020s. The idea itself has returned unchanged and, apparently, is here to stay.
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