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From April 19th to 26th this year, the U.S Navy conducted the “Unmanned Integrated Battle Problem 21” exercise off the coast of California. The goal of the exercise was to examine how the U.S Navy can use aerial drones, as well as autonomous surface and subsurface vehicles at sea and in the air to support a manned fleet in an integrated battle. One of the notable events from this exercise was the disclosure that a swarm drone attack was successfully undertaken against a surface vessel target. No further specifics were given regarding this event, not even whether the drone swarm involved unmanned aerial, surface or undersea vehicles. However, with programs such as the LOCUST (Low-Cost UAV Swarming Technology), it is evident that the U.S Navy is working on each vehicle type.

Gremlins, a program focused specifically on aerial platforms, is another such program that will be tested in the October to November timeframe this year. This program is conducted by the U.S Defense Advanced Research Projects Agency (DARPA) who has partnered with Dynetics, a subsidiary of Leidos, and Kratos Defense. It will test controlled drones that are dropped out of cargo planes, to swarm enemy defences ahead of ground vehicles, ships and aircrafts.

Mission Kill

The premise of swarm attacks is straightforward – the defender is overwhelmed by sheer numbers. It is envisioned that these unmanned systems will be easily and readily deployed in mass and would be operated either autonomously or controlled from a distance, thus being able to overwhelm a defender.

It is not necessary for unmanned systems to carry explosives or depend on using kinetic impact energy to cause damage. For example, to damage a modern warship, it is not necessary for unmanned systems to be able to sink it. Because of a warship’s complexity and dependence on its electronic systems and sensors, it would be enough to just cause significant damage to the vital electronics, communications, sensors or weapon systems, thus rendering the ship useless. This strategy is known as “mission kill”.

Another way to render such a ship unusable, if one was willing to go against international law, is through a toxic payload. Radioactive material, nerve and chemical agents could just as readily be employed through unmanned systems. In a cold equation, damaging or crippling a ship may actually be more advantageous than sinking it. A damaged ship would have to be escorted to a safe port or shipyard for repairs, thus diverting ships to escort it and expending resources to repair it. A sunken ship would of course have to be replaced, but the same can be said for a damaged ship regarding immediate operational tasking.

Leading Limitations

The premise of unmanned systems swarming a target is attractive, however there are several limitations that need to be kept in mind, particularly ones that lessen the viability of usage in some countries. The current state of technology means that unmanned systems have a limited range, and as a result in most cases, require a mother vessel to deploy them from. It is a lesser problem if one is deploying them in defence of a coastal or island installation where concealed positions are available, however even in such situations there are limitations. Drone swarms may play havoc with amphibious or airmobile forces attempting a direct assault but will not be able to do anything against ships firing missiles from a considerable distance away or against airstrikes.

With mother vessels carrying drone swarms, the main challenge is to get the mother vessel into a place where it can deploy the swarm and ensure that the unmanned systems are not constrained by its own limited range. At the same time, a mother vessel is just as vulnerable to detection and attack at any time, particularly so if it is a surface or aerial vessel that can be engaged by long range anti-surface or anti-air missiles, which are prevalent on most warships. The most viable option would be a submersible mother vessel, but even that has limitations. A submarine would need to be of a certain size to deploy a swarm, but this then faces the inherent issues of vulnerability to detection with any increase in size. If the vessel is a not a dedicated mother vessel but instead a traditional submarine with space pre-purposed for other roles, then space for unmanned systems would be too limited.

Additionally, the range and size of the swarm also must be factored in. With the idea behind a swarm being that the attack number is too high for the defender to counter, the swarm must be deployed either at close range and/or at a speed that gives the defender little time to react. That, and a sufficient number of drones need to be deployed for it to be a successful swarm.

Technological progression in engines or power generation may give unmanned swarms greater range and endurance, but this is still very much in the future. It will also most likely result in a trade-off between size, numbers, performance, range and costs. For example, a longer range or faster speed may be possible but at the expense of increasing size, taking up more space on the mother vessel and more expense. However, smaller versions result in shorter-range and less speed.

A question of control

Additionally, there is also the question of control of the drone swarm. Should they be autonomous artificial intelligence systems or remotely controlled from a station? Autonomous AI brings about a question of ethics as to whether autonomous killing systems with no human control should be fielded in the first place. Although they do have the advantage of not being dependent on controlling signals that could be interfered with, either through control signal disruptions or destruction of the control centre, the ethical implications remain. A kill or stand down signal brings about its own vulnerabilities to being spoofed or hacked by the opposing side. Thus, an internal timer system prompting automatic shutdown or destruction after a certain period may be a better option, although there is always the possibility of such systems failing.

It should be noted that many of the instances of drone operations in combat have been in cases where the drones operate largely in an uncontested environment. Some early lessons can be drawn in the recent Israel-Palestine conflict with Israel’s Iron Dome system and fighter aircraft having destroyed Palestinian drones, though it must be cautioned that the Palestinian drones were not deployed in swarms. Given the success of the Iron Dome system against rockets, it can be assumed a drone swarm will just as similarly be thwarted, as has been the case with mass rocket barrages. But at the same time, it is important to note that the Israeli defence is a layered defensive system protecting a country. An individual smaller target on its own, one lacking a sufficient layer of defence systems, may be more vulnerable to a swarm, particularly if the target is a vehicle, ship or aircraft.

A question of effectiveness

The question of drone swarm effectiveness carries on also to the maritime domain. Are drone swarms able to overcome existing weapons deployed, ones such as close-in weapon systems, rapid fire cannons, miniguns, machine guns, and at the last resort, assault rifles? Will the literal “throwing up a hail of lead” be overcome by a drone swarm?

These are questions yet to be proven either way. Once a system is deployed, counter measures against drone swarms will be developed and deployed, such as signal disruptors and jammers, airburst munitions, and capture nets. Additionally, once such technologies mature, there could even potentially be electromagnetic pulse and microwave/heat emitters that could knock out the internal circuits of drones.

Still, this does not mean drone swarms are not viable. The matter lies more in properly understanding their capabilities and limitations, and then deploying accordingly. A drone swarm using the element of surprise and deployed from a concealed position or (what would appear to be) an innocuous civilian vessel could cause damage to an unsuspecting target. Particularly so if used in congested, cluttered, and narrow waters or in a port. At the same time, a drone swarm can be used by ships or oil platforms to counter fast small craft boats attacking or attempting to board – such crafts will not be generally able to carry countermeasures against drone swarms. Lastly, amphibious and aerial assaults could also be disrupted by a drone swarm, if concealed and deployed properly.

The main takeaway is that, as with any other weapon, effectively understanding the capabilities, limitations, and the correct conditions in which to employ unmanned systems and swarms is the key.

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