The US Navy recently said it had spent at least $500 million shooting down Houthi drones and missiles in the Red Sea, expending 220 missiles, many of which cost several million.
While many of the drones shot down within the 15-month period were hit with cheaper guns – sometimes fired from helicopters – there is a race to slash the cost of intercepting drones – which can cost as little as tens of thousands of dollars.
The Houthis, a rebel group in Yemen, “can rapidly create things that are much simpler than what the United States produces”, former US National Security Adviser Jake Sullivan said. “They’re not as good, but are certainly good enough to have significant battlefield effect.”
The Houthis' Waid 2 drone, based on the Iranian Shahed-136, is thought to cost at least $50,000, although some estimates put the price tag over $300,000, likely due to supply chain challenges.
Lasers, said to cost a few dollars a shot, have worked in testing in the US and British armed forces, but due to continuing technical challenges, have not been used in combat. The UK, US and China are working on microwave weapons to “fry” drone electronics, but these require large amounts of energy and have short range.
AI-assisted machine guns, like the US Bullfrog, could be the next frontier. But there is a problem: drones are getting cheaper too, and 3D printing could soon play a critical role in the deadly war of price reduction. Already in Ukraine, drones like the 3D-printed, long-range Titan Falcon and the largely 3D-printed Liberator used by rebels in Myanmar are shaping the battlefield, at lower cost that US military drones in the same class.
Worse, cheap decoy drones are often used in Ukraine, while killer drones can fly at high altitude. That makes the slow-moving targets – that normally creep under the radar – easy to spot.
But according to one defence analyst who frequently visits Ukraine, higher flying drones force defenders to use expensive missiles to hit them, rather than cheaper streams of bullets that cannot reach altitude.
At the same time, other drones swarm in low, reducing the available time to intercept them.
3D-printed death
With the spread of 3D printing, these swarms could get easier to build. Other innovations to keep drone costs down include South Korea’s recent Papydrone, made of cardboard, following a similar innovation in Ukraine. But 3D printing offers the prospect of longer flight times and “endurance”.
“You can now print sections of wings for two metres to four metres. Strong materials are available, and the mechanisms for linking them together easily so that they are well integrated exists. But also these 3D printers are coming out with larger beds now. So it used to be you needed a 255mm bed by 255mm but now larger beds are available on printers you can get off the net,” says David Kovar, an expert on drone forensics, the study of armed drones.
The technology – at least for militias and terrorists – is still in its infancy and mainly used for what the US call Group 1 drones – small quadcopters fitted with bombs. This was on display in Syria, where a lightning offensive by Hayat Tahrir Al Sham used drones with 3D-printed parts that might otherwise be unavailable to a designated terror group, to overwhelm the Syrian army.
For militias, bigger and longer-range systems are coming, although the 3D printing trend here is lagging behind official US and UK efforts, like the Lockheed Martin-funded Firestorm Labs. In Myanmar, rebels have the mainly 3D printed “Liberator” drone that is said to cost about $5,000 with a 40km range.
Several experts have identified 3D printed parts in drones used by Iran, with technology passed on to groups in Iraq and the Houthis in Yemen.
“Even a couple of years ago we were spotting that the battery management system, its casing and other parts had been printed on a fairly large 3D printer for Iran-backed groups. One continuous piece, something to hold all of the batteries within a drone system. So it was things like casings and internal bodywork and structure that we found were being 3D printed,” says Michael Knights, an expert on Iran-backed militias at the Washington Institute for Near East Policy.
The advantage is clear: when Iran passed Shahed drone technology to Russia with the aim of building 6,000 Geran drones – the Russian variant of the Shahed – for the Ukraine war, there was a delay sending across plans, according to researchers at the Institute for Science and International Security.
In the future, files for 3D printed designs can be sent instantaneously and some Gerans have been found with 3D printed parts, according to the Conflict Armament Research, an NGO. Other delays in the drone production included a lack of skilled workers, something 3D printing, or additive manufacturing, is good at overcoming once people are trained to use the technology.
It allows drone designs to be quickly customised, for example a drone designed to carry a bomb can be modified to carry reconnaissance equipment.
“3D printing is definitely the technology of the future and it’s developing extremely fast. One of the projects I’m working on is looking at 3D printed firearms. To give you an idea of where we might get to with drones, the first 3D-printed firearm was shot in 2013 and it was a single-shot pistol, it could only fire one bullet. Now, 12 years later, people are 3D printing firearms that, if made well are almost as good as commercial firearms,” says Rueben Dass, senior analyst at International Centre for Political Violence and Terrorism Research in Singapore.
While typical 3D printing uses resin, metal printing is also advancing, as well as strong lightweight materials like carbon fibre. Mr Dass and Mr Kovar say that controlling supply chains of dual use technology like printers will pose a headache for those trying to stop it falling into the wrong hands, because, Mr Dass says, of the many “legitimate uses” of the tech.
Last year, the US and UK placed export controls on a range of equipment that can be used for 3D printing metal.
Terror supply chains
Mr Kovar gives Ukraine as an example of how restrictions on exports for equipment used in drones was overcome by both sides. He says this can easily apply to the context of global terrorism.
“Ukraine had to build these supply chains for all sorts of components for everything from the small FPV (first-person view) drones all the way up to these seagoing drones. And they couldn’t buy some of these components from the US because they were ITAR (US International Traffic in Arms Regulations) controlled.”
Mr Kovar, who supports Ukraine in its war against Russia, says China soon filled the supply gap caused by ITAR.
“Because both an allied power, Ukraine, and an adversarial power, Russia, have been forced to develop these ‘just in time’ supply chains for all of the various components they need for drones, those supply chains exist for other people to leverage them. And so if Iran is working with Russia, then that supply chain most likely is also available to the Houthis.”
Autonomous killers
Another aspect worrying researchers is the advent of cheaper “computer vision”, including guidance systems that “match” images of terrain with an on-board computer map to navigate.
It makes them impossible to electronically jam, because they do not need a controlling signal, at least for the last part of their flight.
“Let’s say you want to drop something on critical infrastructure in the US. You fly a drone over to take really high resolution video, or you just go to Google Earth, and Google Earth gives you a four month old 180 degree view of the target. So now you’ve got all the imagery you need, and you can train a Jetson AI system to add to your drone,” Mr Kovar says, referring to the AI system developed by US firm NVIDIA, which was found in Russian autonomous Lancet drones, despite US export restrictions.
“Now you can do image-based navigation, and any GPS jamming or denial defence is going to be invalidated. You don’t need an NVIDIA board for some of these solutions. Raspberry Pi will get the job done,” he says, referring to a widely available microcomputer that can be used for computer vision.
The basic concept of image matching for navigation is decades old, but was once the preserve of big budget US arms programmes.
Mr Dass says we are only at the beginning of these trends, although one challenge for militias and terrorists is that the more capable a drone becomes - longer range, with a bigger weapon or better camera - the more electronics and battery power it needs, adding to the challenge of obtaining the equipment.
“As 3D printing becomes more accessible, and as it becomes cheaper, it definitely opens the door to a lot more opportunities for these groups.
“There’s some reports of Al Shabaab now in Somalia, dabbling with 3D printing. We’ve seen Ukrainians, the pro-democracy forces in Myanmar, who are using 3D printing to to manufacture weapons.
“We have this cycle of knowledge sharing, starting between 2013 to 2019 with ISIS and their use of small drones. The same modus operandi was picked up by the Ukrainians. And from there on, in Myanmar, by the rebels there. And the interesting thing about Myanmar is that the rebels first used it, and then the junta followed them. And now it’s everywhere.”
Iran, according to Mohammed Albasha of the Basha Report, a US-based risk advisory service, has an “advanced UAV industry”.
“Domestic 3D printing capabilities, and reliance on self-sufficiency under sanctions make it plausible for prototyping or manufacturing non-critical components. If this is not happening already, it is likely to occur in the short to midterm future, as the future of warfare increasingly relies on autonomous systems with affordable components.
“However, it is important to note that the Houthis do not rely solely on Iranian drone components; there is documented use of Chinese and German engines and European electronic chips, indicating a global supply chain with built-in redundancies. The Houthis are now capable of mass-producing the Samad series drones independently of Iranian parts, though their long-range drones and ballistic missiles still depend on Iranian supplies and logistical support,” Mr Albasha says.
Yoel Guzansky, a senior researcher and head of the Gulf Program at the Institute for National Security Studies (INSS) agrees.
“If the Houthis can print drone equipment inside Yemen, it has a lot of geopolitical and strategic effects, because then they are much more independent on their decision making, and they will need Iran less and less. The Houthis have sustained fighting against global powers for almost a year and a half, showing that with very little support and investment by Iran, they can cause a lot of global damage. They will continue to be a security problem for the Red Sea, Bab Al Mandeb – and perhaps for the world.”
