By Natasha E. Bajema, Ph.D.

Imagine you are spending an evening at your favorite steakhouse in the year 2035. When you place an order for a steak, the waiter asks politely: “And how would you like your steak printed?” You might think you’ve found yourself in an episode of the 1960s space-age animated sitcom The Jetsons. But this is where the kitchen of the future may be heading courtesy of additive manufacturing. Over the past couple years, a little known company called Modern Meadow has been quietly developing techniques for “printing” living tissue such as leather and meat rather than harvest them from farmed cattle. The food industry is one of many sectors being transformed by additive manufacturing, an emerging technology more commonly known as 3D printing. Other frontier developments include the printing of a high-performance car called Urbee, customized running shoes and hearing aids, advanced prosthetics, tiny unmanned aerial vehicles, human organs, full-scale buildings, chemical compounds, and even a base on the moon. The impressive range of applications enabled by 3D printing is one of many reasons the technology promises to have such a broad impact.

As much as 3D printing promises to change our society in positive ways, easy access to the technology offers vast potential for subversion by terrorists. And we are far from understanding the actual implications of 3D printing for national security—both the good and the bad. For most of us, it is difficult to imagine how a manufacturing process might fundamentally alter how societies function and impact our day-to-day lives—all the while creating previously unthinkable opportunities for criminality and violence. After all, new processes for improving manufacturing are developed rather frequently, and the typical consumer does not notice all that much. We do not ask how our products are made or what process was used to make them, we simply buy them and use them. We certainly do not consider how a manufacturing process might fundamentally change things for terrorists seeking weapons of mass destruction (WMD).

Our failure to prevent the terrorist attacks on the World Trade Center and the Pentagon on 11 September was in part a failure of imagination. It requires another stretch of the imagination to envision how terrorists might exploit 3D printing to bring about mass destruction. After all, 3D printing has yet to make a visible and significant impact on many of our lives. A number of recent examples, however, foreshadow the potential of the emerging technology for nefarious behavior by determined actors.

In 2012, Cody Wilson, a second year law student at the University of Texas, and his friends, naming themselves “Defense Distributed” launched the “Wiki Weapon Project”. Using a crowdfunding website, the group raised funds for developing a 3D-printed plastic gun that can be printed using a low cost, open-source 3D printer known as a RepRap. The group successfully produced a plastic gun called “The Liberator” capable of firing a .22 caliber bullet and released the blueprint online. The design was downloaded 100,000 times in just two days before the U.S. State Department stepped in, demanding the removal of the blueprint file from the website under the International Traffic in Arms Regulations (ITAR). Nonetheless, the file remains available on disreputable file-sharing websites.

Using 3D printing technology, several companies have developed commercial drones that are lighter, travel farther and have greater capacity to carry payloads than remote-controlled electronics. Capabilities already exist to 3D-print one drone per day. Systems are being developed to print 25-100 times faster than that. In a single small facility, 10 printers may soon be able to produce 1,000 drones per day. Imagine these were modified to carry improved explosive devices (IEDs) and programed to swarm against a target.

These examples offer only a hint of things to come…

Why is 3D Printing So Revolutionary?

3D printing has widely been referred to as a “disruptive technology” which promises to upset the means of production, global supply chains and the relationship between manufacturers, retailers and consumers. Industry experts, scientists and policymakers agree that 3D printing may lead to another industrial revolution. For over two centuries, the economies of developed countries have depended on advanced manufacturing processes, which add value to raw materials by transforming them into finished products that are then consumed by households. Today, these processes—plastic injection molding, casting, stamping, forming and machining—are used to mass produce everything from airplane parts and car parts to electronics to everyday household items such as paperclips and thumb tacks. Each process begins with a block of material that is turned into a final part by removing and/or shaping material using a variety of different methods.

Additive manufacturing is best understood when contrasted with these “subtractive” and “forming” processes. The term “additive” refers to a family of technologies through which material is added gradually, layer-by-layer (printed), in order to build up an object from a digital blueprint. At breathtaking speed, engineers are developing many new techniques, all of which apply the same conceptual process, but use different material types and forms and different printing methods for adding and fusing layers to build objects. Although plastic is the most common material used in 3D printing, a wide range of materials or “inks” are currently being used in commercial and scientific sectors including plastics, resin, metals (steel, aluminum, bronze, copper, titanium, gold and silver), ceramics, living tissue, chemical compounds and nanomaterials.

Every print begins with a digital 3D blueprint acquired via one of two pathways. The first path starts with the digital 3D blueprint itself. A 3D blueprint is developed using modeling software such as computer-aided design (CAD) software or purchased and downloaded from the Internet. The 3D blueprint is converted to an “STL” file using “slicing” software, which divides the three-dimensional model into horizontal cross-sections of varying thickness that can be printed sequentially. The second path begins with any object. A 3D model is produced by scanning an existing three-dimensional object and creating a digital model. Scanning does not capture the mechanical functionality of the object. For a complex object, each part would have to be separately scanned and assembled to achieve full functionality. The digital model can be modified using modeling software and converted into an STL file. To perform a print, the 3D printer reads the digital 3D blueprint, lays down successive layers of material and builds the object.

In addition to its capacity to do new things, 3D printing is first and foremost a digital technology. This means that in time, it will become easier to use, more affordable and increasingly available to anyone with access to the Internet. 3D printing is called manufacturing for the masses, because anyone can do it. With just a computer, 3D printer and design software, anyone can design their own products on the computer or purchase and/or modify an existing digital product design. Once a digital file is acquired, anyone can print finished products and distribute the digital blueprints instantly anywhere in the world. In other words, anyone with access to the Internet will be able to create and share physical things over the Internet, and this will change the world as we know it.

3D printing is expected to bring about a shift of manufacturing from large-scale factories to many new smaller production spaces even including our desktops at home. For decades, manufacturing has moved overseas to capitalize on cheap labor and has been centralized to leverage economies of scale. Thus far, offshore labor has been cheap enough to offset the cost of shipping parts across the globe. However, the features of 3D printing are causing companies to reexamine cost-benefit trade-off of manufacturing overseas. The manufacturing of the future will be distributed with close proximity to customers and this will disrupt traditional supply chains and distribution channels.

It’s not necessary to buy a 3D printer get into the manufacturing biz. Simply use the 3D printing services offered by existing companies and start-ups. Today, your local Staples or UPS store will 3D-print objects on site. Alternatively, you can visit new online start-up companies such as Shapeways, which provides 3D printing services to consumers, who can upload digital files, customize objects using simplified web based customization software, and order the items as 3D printed unique objects. With imateralise, you can even upload digital 3D blueprints directly from your iPhone, use simple software to modify the design from your phone, choose from 100 different materials for your object, and order the printed object.

3D printing is also refining the nature of economies of scale. Manufacturing is no longer solely focused on producing very large numbers of identical products or parts. 3D printing allows for the manufacture of custom products on-demand. Leading manufacturers such as BMW, Bentley, Nike, Adidas are exploiting the low production volume cost advantage offered by 3D printing to partake in the growing market for customized products. These companies are tweaking designs at minimal cost to match specific customer preferences. 3D printing has literally transformed industries for prostheses and other custom medical devices. Whereas a typical prosthesis costs over $60,000, a desktop 3D printer, the MakerBot Replicator 2.0, can print most of the plastic components for a Robohand for only $2,000 and easily print replacement parts as needed.

A 3D printer can be housed in a much smaller factory (or even a garage) compared to the traditional manufacturing line. The small footprint of 3D printing allows for manufacturing of parts practically anywhere. Simply send 3D printers and raw materials into the field and transmit designs electronically. NASA is taking advantage of this feature on the International Space Station. Made in Space designed ratchet wrench and sent the design into space where it was 3D-printed in outer space. The European Space Agency is looking at the possibility of building a base on the moon using 3D printing. Building a base on the moon could theoretically be made much simpler by using a 3D printer to construct it from local materials such as lunar soil.

3D printing may revolutionize the supply chains and logistics across many sectors such as the shipping industry Maersk Tankers is exploring the idea of installing a 3D printer on a tanker vessel to allow the crew to ‘print off’ spare parts they need. It is also possible to imagine a new paradigm of manufacturing in which a tanker travels to a country, picks up raw materials and then prints products while en-route to the customer. Other new manufacturing platforms include aircraft, submarines and even the battlefield. For example, the U.S. Navy is experimenting with 3-D printers aboard ships that allow them to print drones custom tailored to mission objectives from a base set of supplies.

Many companies have been exploiting various advantages of 3D printing for several years, in particular its capacity for design complexity. For centuries, limitations in tooling have constrained the design of parts. Even high-tech computer numerical control (CNC) machines are unable to produce complex geometries because the tool simply cannot reach inside the part to remove the material. As a result, complex parts are typically made up of many different parts, requiring multiple production runs and tool set-ups, which drive up costs and cause production delays. With 3D printing, engineers can create complex geometries that bend, twist and have unique shapes all while consolidating many parts into one. This leads to innovative, lighter and more efficient product designs and often better performance because fewer welds increases durability.

For example, Boeing is using 3D printing to produce a cooling duct for the F-18 Hornet, a strike fighter jet already in military service for more than two decades. Previously, the duct consisted of up to sixteen parts that were welded together. Now the duct is a single part that has been optimized for air flow efficiency. General Electric is using 3D printing to make fuel nozzles for its next-generation jet engine, the LEAP. The single-part fuel nozzle is twenty-five percent lighter than the previous eighteen-part model and five times more durable.

It’s clear that 3D printing will change the world in many profound ways, but how will 3D printing technologies enable terrorist groups to develop and use WMD in the future?

How will 3D Printing Change the Game for WMD Terrorism?

The impact of 3D printing as an enabler of WMD is still very much in the theoretical realm. Answering this question requires us to stretch our imaginations once more. We must put ourselves in the shoes of a terrorist group operating within a constrained and risky operating environment and imagine the new possibilities afforded by the extraordinary features of 3D printing. In the future, 3D printing will change the game for terrorist groups in three major ways.

Time and Space

Due to its small footprint and digital format, 3D printing affords easy access to time and space to terrorist groups. In the past, terrorist groups required a stable physical space from which to plan and implement complex attacks. A physical safe haven, usually found within a country with a weak or hospitable government, provided the space to develop the infrastructure for producing WMD-related materials and bought time to carry out operations. The safe space concealed illegal activities and helped terrorists to remain under radar and avoid detection. Finally, the physical space offered a place to gather up necessary weapons, equipment and supplies and to plan logistics for an attack.

Since 9/11, the Internet has served as a virtual safe haven, and it is increasingly reducing the need for physical space for terrorist groups. Virtual safe havens are global, highly flexible, expendable, difficult to track and nearly impossible to control. Terrorists now use the Internet as a primary meeting place via chat rooms, online video games, Skype, Google Chat. Terrorist groups conduct training using video-conferencing technology. Social media offers a highly effective tool for recruitment, branding and marketing. The Internet offers access to online banking and digital currency, illicit services and black markets from the Dark Web and online retailers such as Amazon and others. The Internet also serves as an unprecedented source of information. Terrorists have at their fingertips access to detailed maps, directions, satellite imagery, addresses and phone numbers, photos of buildings, site maps, do-it-yourself manuals on WMD, recipes for chemical agents and instructions on growing bacteria.

With the rise of 3D printing, terrorist groups will also harness the Internet to aid in manufacturing weapons and other critical items for their complex operations. Terrorist groups can receive and send blueprints electronically for weapons from a space the size of a garage located in any country with access to the Internet. They can receive shipments of materials and equipment at their doorstep delivered by  shipping company, print parts and assemble weapons. And, they can do all of this without even leaving the space. Operational flexibility is practically unlimited. Individual terrorist cells could be instructed to produce specific parts that would later be brought together for assembly in a different location. If one location was compromised, they could simply move and shift activities to another existing location. All digital files would simply be send by email and downloaded from the next location.

The digital nature of 3D printing will allow terrorist groups to better evade authorities, which depend on tracking locations, movements, and tangible activities for their investigations. Terrorist groups already use various methods for hiding code inside videos or obscure internet locations. They will be able do the same with digital 3D blueprints. Although terrorist groups may still require some physical space, their options for finding that space will become more numerous and agile with 3D printing.

Embedded Expertise

3D printing will allow terrorists to circumvent the need for engineers and scientists with embedded expertise. In addition to time and space, terrorist groups typically need access to technical expertise to plan complex attacks, especially with WMD. Specific expertise and skills are required to design a weapon and then to translate the design into a finished product using advanced tools such as lathes or computer numerical controlled (CNC) machines. But what if a terrorist group could simply download a weapon design and assembly instructions from the Internet?

Digital blueprints, designed and tested by scientists and engineers, embed a certain level of technical expertise in electronic form. This embedded expertise allows people without the requisite skills to produce parts or objects by simply loading up a 3D printer with the required raw materials and then pressing the print button. Of course, these blueprints do not include post-print finishing and assembly. However, a digital build file sold online could come with instructions for finishing and assembly.

Some industry experts predict that consumer-level printers will become powerful home appliances. In the future, homeowners needing spare parts for a dishwasher may order the part online from the manufacturer, receive the digital blueprint and then 3D-print the part on a printer at home or have it printed at a local 3D printing center such as Staplles or the UPS store. Like consumers, terrorist groups are increasingly able to download or purchase digital files online. The number of 3D models available online is growing exponentially. Consumers can download free designs from open source design repositories like Thingiverse, Shapeways or Google Sketchup. Thingiverse, for example, has over 100,000 items in its repository. While most of the available items are innocuous, there are 3D designs for functioning guns available online. The plastic gun called “The Liberator” was primarily noteworthy for its small number of parts and ease of assembly supported by detailed instructions. The gun has 15 parts, and assembly time is roughly one minute.

As leading manufacturers, the military and engineers further explore the potential of 3D printing, more embedded expertise may become available to terrorist groups. Some of this digitized expertise may include sensitive build files for advanced weapons technology not otherwise available. For example, Raytheon recently announced the capability to print over 80% of a guided missile’s components, with 100% capability a stated near-term goal. This would allow soldiers to 3D print guided missiles in the field as needed. If terrorists were able to gain access to sensitive digital files, they may be able to gain access to advanced technology traditionally only available to the military. Digital files are vulnerable to hacking, theft and interception and are much easier to copy, distribute and pirate than physical objects.

The prospect of embedded expertise raises some critical questions. Will it change the game for experienced engineers and scientists who seek to profit from their expertise (e.g., like A.Q. Khan)? Will the Internet/Dark Web provide sufficient anonymity to lower the moral barrier for helping terrorists develop WMD by providing digital blueprints?

Will the access to greater expertise lead to more innovation among terrorist groups? Although terrorist groups profess great interest in WMD, terrorist groups continue to demonstrate a preference for guns and bombs. Terrorists appear to be dissuaded from using WMD due to higher investment of resources, time and expertise, a greater risk of detection, and unpredictable results.

Access to Materials and Equipment

3D printing may offer terrorist groups easier access to materials and equipment in the future. The difficulty of gaining access to materials and equipment, has long served as a primary obstacle to the development of WMD. With 3D printing, states and non-state actors can acquire raw materials such as aluminum, titanium and steel in the form of powders and wire to produce the items and equipment rather than controllable finished products or dual-use items.

In this way, they could circumvent export controls put in place to prevent WMD proliferation. For example, gas centrifuges, assemblies and components for uranium enrichment are subject to export controls under the Nuclear Suppliers Group guidelines. The materials needed to make these components such as maraging steel and aluminum are also controlled. Today, both of these materials exist in powder form that can be used in 3D printing. It is far easier to hide maraging steel in powder form than in large bars, sheets or tubes. Moreover, as raw materials in powder and wire form, these materials are not merely a dual-use problem (with legitimate and illegitimate uses), they present a multi-use problem due to a significant amount of gray area between legitimate and illegitimate uses. For example, terrorist may soon use 3D printing to enhance their access to materials and equipment in both legitimate ways (e.g., printing legal steel parts) and illegitimate ways (e.g., printing illegal weapons) to support their complex operations.

With its capacity for design complexity, 3D printing will make it much easier to print centrifuge and nuclear weapons components. Given the enormous investment required for uranium enrichment, terrorists are not likely to go down this path in pursuit of a nuclear weapon. Nonetheless, current efforts underway to support the U.S. nuclear weapons program demonstrate the massive advantages offered by the technology. The Kansas City plant, part of the U.S. nuclear weapons complex, has been using 3D printing to design and produce non-nuclear components to improve the way they are designed and manufactured. Kansas City plant engineers experimented with lower-end 3D printers to see what they could do with the technology—they found advantages in quick and easy production value at these lower-end desktop printers. In fact, they saved $10 million in development costs using 30 MakerBot printers for prototyping

And what if terrorists could someday use 3D printing to gain easier access to harmful pathogens, microbes and chemical compounds?

Organovo developed the first 3D bioprinter in 2009 for making human issue and organs. To print an organ, scientists take a small piece of tissue from the patient’s organ and then tease the tissue apart into its individual components. After a month of growing the cells in a lab, they are combined with a gel and fed into a printing cartridge. The tissue is then printed layer by layer to form a 3-D shape. Using this technique, doctors may soon be able to produce soft-tissue implants such as blood vessels and eventually build a whole organ – such as a liver or kidney – complete with all of its blood vessels.

Meanwhile, in the UK, Dr. Leroy Cronin of University of Glasgow wants to create downloadable chemistry, with the ultimate aim of allowing people to “print” their own pharmaceuticals at home. In his lab, his team has used a 3D printer costing less than $2,000 to build a prototype chemical 3D printer, which could be programmed to make basic chemical reactions and produce different molecules. After the microreactors are printed, he injects “chemical inks” to create sequenced reactions. He envisions that it should someday be possible that with a relatively small number of inks you can make any organic molecule. In the future, he expects that consumers will be able to print their own medication from the comfort of their home. This may sound like science fiction, but the FDA already approved the first 3D-printed drug last year.

The good news is that technologies for printing drugs and human tissue are very early in their development, still require tremendous expertise and advanced skills and are not likely to become widely accessible in the near term. It remains uncertain to what extent these tools would be useful for a terrorist group. However, these technologies demonstrate the enormous potential of 3D printing across an incredibly broad number of sectors that could be leveraged by terrorist groups in the future.

There is Still Time to Adapt, but Not Much

For policymakers concerned about the impact of 3D printing on terrorists seeking WMD, there is still time to adapt. The amount of time depends on the rate of technology adoption, which is difficult to predict. Terrorists tend to favor low-technology options. If a 3D printer becomes the new desktop printer, then terrorist groups are more likely to leverage the technology to enhance their operations. Industry experts disagree about the future of 3D printing, and some contend that it will remain a niche market for decades. Many obstacles remain before 3D printing will become adopted by a majority of consumers. For one, the vast range of materials used to create household products is not practical for the average consumer, who would also not have the requisite skills to use the device effectively to produce the quality parts they desire. The cost of materials is still expensive, and consumer-level printers are slow.

However, the challenge for policymakers extends beyond technology adoption. Emerging technologies like 3D print may create new WMD development pathways and enable existing ones, leading to increased capability of terrorists to develop and use WMD. Since 9/11, there has been a growing recognition that policymakers need to focus more resources on tracking people with ties to terrorist groups and access to “dangerous stuff” rather than simply tracking the dangerous stuff itself. Unfortunately, most of the current tools designed to prevent and counter WMD proliferation are focused on controlling and tracking the stuff and not people. This problem becomes even more acute with the rise of 3D printing. A digital design can be sent anywhere in the world and production can be localized. The “stuff” is no longer physical, it is digital information, and it is impossible to have airtight controls over the transmission of digital information. As such, emerging technologies, including 3D printing may be leading to a paradigm shift in countering WMD.

3D printing is an attractive technology for terrorist groups seeking to conduct complex attacks, including the use of WMD. We have not yet seen terrorist groups harness the technology to develop WMD. It remains unclear to what extent these advantages will lead terrorist groups to move beyond the use of guns and bombs to explore the use of WMD. However, if 3D printing significantly reduces the required investment of time, resources and expertise to develop WMD, terrorists will be more likely to use WMD in their attacks.

The views expressed in this blog are those of the author and do not reflect the official policy or position of the National Defense University, the Department of Defense or the U.S. Government.