How the new laser beam works that allows you to shoot down drones from a distance and at a very low cost

British DragonFire laser air defense system (BRITISH MINISTRY OF DEFENSE/)

A flash of light is directed towards a tiny drone flying at breakneck speed. Moments later, the disabled drone crashes into the sea. No sound, no human casualties, no messy explosions. A deadly multimillion-dollar drone was cleanly eliminated by a shot that cost less than a good bottle of wine.

If you think this is a scene straight out of a science fiction movie, think again. Just a few days ago, a team of British scientists and engineers managed to demonstrate that This is a viable technology that could reach the battlefield within five or ten years.

DragonFire is a $38 million high-tech program launched in 2017, involving the British government agency Defense Science and Technology Laboratory, missile manufacturer MBDA, aerospace company Leonardo UK and defense technology company QinetiQ. The program successfully completed its first field test by shooting down several drones off the coast of Scotland using laser beams.

Drones are unmanned semi-automatic aircraft capable of inflicting lethal damage with great precision. They are common on modern battlefields, especially in the Ukrainian war and on the Red Sea naval trade routes.

They are not easy to shoot down, as they often require missiles that cost up to a million dollars each. Although often effective, defensive systems of this type are expensive and carry a high risk of collateral damage. If a missile misses its target, it will end up landing somewhere and explode anyway.

But you don’t need to cause a spectacular explosion to disable a drone… just interfere with its control and navigation systems.

And a laser beam is a very good candidate for this task.. Lasers are especially directional beams of light, which can be very intense. A sufficiently powerful laser can interfere with any electronic device and cause it to malfunction.

The DragonFire laser system.
The DragonFire Laser System

Compared to conventional missiles, a high-power laser system offers a number of strategic advantages. To begin with, its operation It’s surprisingly cheap: Running the DragonFire for ten seconds costs the same as running a heater for an hour (or less than £10 per shot).

Lasers also pose no risk of collateral damage.. Even if a laser does not reach its target, it will continue to propagate in the same direction and will end up being absorbed and dispersed in the atmosphere. Since the laser is a beam of light, it propagates in a straight line, regardless of gravity. Finally, the cross section of a laser beam is usually very small, on the order of a few square millimeters. In this sense, its use is similar to a surgical operation.

Lasers are, therefore, a defensive weapon par excellence: they can respond to a threat, but they cannot cause significant damage. Furthermore, they are very insensitive to countermeasures, since the light beams travel at the highest possible speed: that of light. In other words, once a laser beam is launched, nothing can reach it and neutralize it.

Lasers have long been used on the battlefield. In the defensive field, they are mainly used for target tracking, remote sensing and precision targeting. But this is the first time they have been used effectively to disrupt enemy action.

Future challenges

Developing the DragonFire as a weapon has taken a long time. This is because neutralizing a drone requires a high-intensity laser beam.

But if the laser beam is too powerful, it can interact strongly with the air in the atmosphere, causing it to be absorbed or scattered. Finding the perfect balance between beam parameters such as power, wavelength and shape is necessary to ensure it can propagate over long distances without significant degradation.

A laser beam is also especially sensitive to atmospheric conditions, and the presence of fog, rain or clouds can significantly affect its performance.

Drones and subsonic missiles are a growing threat around the world. That’s why the UK Ministry of Defense is accelerating development of DragonFire, hoping to bring it aboard warships in the next five to ten years.

A number of technical and scientific issues still remain to be resolved.

For example, It is not easy to maintain the stability of laser aiming on a moving platform (like a cruise in rough waters). It’s like trying to hit a target while standing on a balance board, but this only affects the accuracy of the weapon, not the risk of collateral damage.

Laser system performance will also have to be decoupled from weather conditions. As water droplets and air currents can disperse or absorb the laser beam, reducing its power and therefore its effects, it would be necessary to be able to take meteorological conditions into account when preparing the beam. This task is not impossible, but it is technically difficult.

It is also necessary to establish a training program so that soldiers can effectively use such a high-tech system.

However, these first tests have demonstrated the viability and effectiveness of this laser weapon, which could revolutionize modern warfare in the coming years.

*Article published in The Conversation. Car is Professor in the Faculty of Mathematics and Physics at Queen’s University Belfast.