The US Navy wants swarms of thousands of small drones

The US Navy is working on ways to build, deploy, and control thousands of small drones that are able to flock together to overwhelm anti-aircraft defenses with sheer numbers, budget documents reveal.

The conflict in Ukraine has proved the worth of small drones, including consumer quadcopters, which have carried out reconnaissance, guided artillery fire, and destroyed tanks. Such drones are currently limited by the fact that each one needs its own operator. In a swarm, however, hundreds or thousands of drones are controlled as a single unit.

The significance of drone swarms is that they can be conceivably applied to virtually any mission." says Zachary Kallenborn, a policy fellow at the Schar School of Policy and Government at George Mason University.

Many nations are working on such swarms, including China, Russia, India, the UK, Turkey, and Israel, which in 2021 became the first nation to use swarming drones in combat. The US Navy has always been a leader in this field, and while they did not respond to requests to discuss their work, the budget documents that MIT Technology Review has read reveal ambitious plans for swarms vastly bigger than anything yet seen. Buried in hundreds of pages of budget numbers are details of several projects not previously revealed, which involve drone boats and submarines as well as uncrewed air vehicles.

Together they fall under a project named Super Swarm.

Flock like a bird

You might have seen drone light shows, in which hundreds or thousands of drones fly together with perfect synchronicity. These are not swarms; each drone flies along a choreographed, predetermined route. The individual drones have no awareness of their surroundings or each other. By contrast, in a swarm the drones fly together and are aware of their surroundings, how close they are to one another, and use algorithms to avoid obstacles while not getting in each other's way, like a flock of birds. More advanced versions use AI to coordinate the actions for tasks such as spreading out to search an area or carrying out a synchronized attack.

The US Navy has already made considerable progress in this area. In 2017 it demonstrated a swarm of 30 drones flying together. The idea is that the drones carry explosive warheads for kamikaze attacks, making them into miniature cruise missiles. The same approach has been used by Russia against Ukrainian cities in recent days. That project, named LOCUST (for low-cost UAV swarming technology"), now falls under the bigger Super Swarm mission.

In April last year a Navy drone swarm carried out an attack on a ship in a war game exercise for the first time. Even in a real mission, Kallenborn notes, the drones would carry just a few pounds of explosive each, compared with the 488-pound warhead on a Harpoon anti-ship missile. That means they would be used in different ways, taking advantage of their high precision.

The drone swarm could attack from multiple angles, aiming to damage or destroy critical systems like radar antennas, deck guns, and weapons systems," says Kallenborn.

The Navy's plans in the budget document include swarms launched from ships, submarines, aircraft, and ground vehicles, in what they term multi-domain operations." The drones will have a variety of payloads: some might carry sensors, some will have jammers or other electronic warfare gear, and some will have warheads. But drone swarms still struggle with the problem of limited range. The 13-pound Raytheon Coyote used in the LOCUST program, for example, can cruise for only two hours at 50 miles per hour, so it needs to hitch a ride.

Another project, DEALRS (for deployment and employment of autonomous long-range systems"), seeks to overcome this challenge. One aspect of DEALRS is working on so-called marsupial systems or motherships: larger uncrewed aircraft carrying multiple smaller drones. Two US drone makers, Kratos and General Atomics, have already demonstrated bigger drones launching smaller ones. But these only involved one or two vehicles, whereas DEALRS aims to transport and launch extremely large numbers" of small drones without human intervention.

Another Super Swarm sub-project seeks to overcome a fundamental problem of military hardware: cost. The US Army pays around $49,000 for each of its small portable drones, known as Rucksack Portable Unmanned Aircraft Systems. Expendable swarming drones will need to be far more affordable to be fielded in large numbers. A project called MASS (manufacturing of autonomous systems at scale") is using 3D printing and digital design tools to create low-cost drones in large numbers. The aim is to have a design that can be modified at will to turn out drones optimized for different purposes-for example, maximizing speed, endurance, stealth, or payload-from the same production line.

According to budget documents, MASS will manufacture drones as far forward/afloat as possible," suggesting production on board Navy ships closer to the action. The stated goal is to turn out tens of thousands of drones.

Control and command

The Navy also wants a more sophisticated control system. Super Swarm already includes cooperative planning and allocation of tasks to swarm members, and another sub-project, known as MATes (for manned and autonomous teams), aims to make it easier for humans and swarms to work together and give the swarm more autonomy.

The communications bandwidth available for the operator may decline during the mission-for example, as a result of deliberate jamming-and MATes allows the swarm to act on its own initiative when it cannot get decisions back from the operator. MATes also feeds back information gathered by the swarm into its decision making: it may change its routing when drones detect new threats, or send drones to investigate a newly identified target. This will be quite a challenge for artificial intelligence.

Thousands of autonomous drones mean thousands of points for error," says Kallenborn. Modeling and simulation would help reduce the potential for error, but accounting for the myriad complexities of the real world is tough."

The first wave

If all the Super Swarm projects come together, a US naval force will be able to launch massive swarms to travel long distances, carry out detailed reconnaissance over a wide area, and find and attack targets. Ukraine's small drones have destroyed over a hundred Russian armored vehicles; a swarm of a thousand drones might take out an entire battalion in one strike. It could direct additional drones against a target that survived the initial attack, and provide detailed imagery of the results.

The budget documents suggest that the swarms are seen as an answer to one of the US military's biggest headaches: anti-access/area denial" (or A2/AD), military jargon for areas covered by advanced surface-to-air and anti-ship missiles that prevent US forces from entering.

Swarms could break through the strongest existing defenses; dozens or hundreds of drones might be shot down, but thousands more would get through, with enough munitions to take out air defense radar and other defenses. This would pave the way for attacks by cruise missiles, crewed aircraft, and other traditional weapons.

Peter W. Singer, a Strategist at the think tank New America and an authority on drone warfare, says Super Swarm faces daunting challenges-in particular, developing swarm coordination beyond simple movements to hunting as both a pack-but that the problems seem surmountable.

In many ways it is no more daunting than the idea of flying a plane off a ship, or coordinating the movements of hundreds of manned planes, must have seemed to generations past," says Singer.

The swarm could take on all sorts of other missions, from reconnaissance and intelligence gathering to electronic warfare and supply delivery. As Singer notes, it could work alongside crewed systems.

Just as Amazon envisions a world of both robotic 18-wheeler trucks for bulk and small delivery drones for the final mile, we'll likely see the same with their military parallels," he says.

Kallenborn says that Super Swarm will not necessarily be a war winner, because military researchers are already working on ways to counter swarms.

Every weapon has a counter. The question is how reliable and effective those counters are," he says.

However, he says it may take some time to develop and deploy such countermeasures, which might include lasers, microwave weapons, or interceptor swarms. Singer also notes the many counters under development, but he sees the arrival of Super Swarm or something like it as inevitable.

Anyone who argues swarms of drones won't appear on a future battlefield is one day going to sound like the people who once argued that the submarine or tank or airplane were mere science fiction," says Singer. It ignores not just what we are seeing in wars like Ukraine, but also what militaries and companies around the world are working on now."