Military robots, in the form of unmanned aerial vehicles (UAVs), first gained major public attention during the first Gulf War, when Iraqi soldiers were seen surrendering to a primitive (by today’s standards) Pioneer reconnaissance UAV.

By post-9/11 operations in Iraq and Afghanistan, the aircraft most closely identified with UAVs by the public, media, and enemy was the Predator, which combined traditional intelligence, surveillance, and reconnaissance (ISR) capabilities with a Hellfire missile, turning it into the world’s first “hunter/killer” aerial robot. But the 1990s and 2000s also saw other UAV developments, from the hand-launched ISR platforms favored by Army and Marine warfighters, to the Global Hawk, the world’s largest UAV, which set a distance record with an 8,214-mile nonstop flight from California to Australia.

In the 21st century, robotics also meant everything from Japanese “runway” models to NASA’s C3P0-like Robonaut to four- or more legged walking robotic pack mules to shoebox-sized robots used to check for car bombs at Iraqi and Afghan roadblocks or see what was inside a building or cave to semi-autonomous rolling carts carrying medical charts and medications around hospital hallways.

But a new breed of robot has now entered the field, in military, homeland security, medical, and almost limitless other applications, at the extreme small end of the spectrum: nanomachines, ranging from the size of grains of sand to the size of insects, hummingbirds, and robins.

The smallest are little more than minute sensors that, when scattered across a path, road, or field, link up to form a sensor net. When a person, animal, or vehicle crosses the resulting electronic web, the information reported by each tiny sensor is aggregated and analyzed by a small field computer then relayed to a command post, alerting warfighters not only to the presence of something within the net but, based on size, speed, and even weight, providing a “best guess” identification.

Larger sensor packs, ranging from the size of a small beetle to a lizard, use mechanical legs or tiny wings or thrusters to crawl, fly, hop, or even slither into buildings, caves, or behind walls, providing sound, video, heat sensor, or other data to the operator. Such information can indicate the presence – and number – of individuals, including otherwise unreachable snipers, in preparation for an attack or hostage rescue. They also can be armed, from small explosive charges to hypodermic needles filled with a range of non-lethal to lethal chemicals, to do the job themselves.

The History, Future, Fears, and Potential of Nanotech
Do a Google search for “micro spy” and more than 330,000 results are reported, ranging from a Nanotechnology News article on “Nanotechnology-Enabled Sensors to Guide Bat-Inspired Robot Spy Plane” in the top spot to “101 Spy Gadgets for the Evil Genius” at the Google bookstore in last. Put “military” in front of “micro spy” in the search box and the results drop by two-thirds, with a Chinese-made “Spy Micro Listener” toy up first and a 2009 video on micro-UAVs (MAVs) last.

Nanotech involves atomic- and molecular-level materials, typically less than 100 nanometers (billionths of a meter) in size, imbued with special electrical or chemical properties for applications in computer memory, semiconductors, biotechnology, manufacturing, energy, power generation, sensors, and more. The concept can be traced to a 1959 paper by Nobel Prize-winning American theoretical physicist Richard Feynman on the potential quantum benefits of miniaturization. Practical real-world research, however, did not become possible for another decade, with the late 1960s to early ’70s invention of molecular beam epitaxy by Alfred Cho and John Arthur at Bell Laboratories, which allowed scientists to control the deposition of single atomic layers and, eventually, build nanoscale devices.

At the official, non-black level, U.S. government efforts in nanotech may be considered to have debuted with the federal nanotechnology initiative proposed in March 1999 by Dr. Mihail C. Roco, a National Science Foundation senior adviser who chaired President Bill Clinton’s interagency subcommittee on nanotechnology. The initiative, which Roco termed essential to “the next Industrial Revolution,” began moving forward when the National Science and Technology Council (NSTC), a subunit of the White House Office of Science and Technology Policy (OSTP), released its first report – authored by NSTC’s Interagency Working Group on Nanoscience, Engineering & Technology – entitled “Nanostructure Science & Technology,” quickly followed by “Nanotechnology Research Directions” and, in February 2000, the “National Nanotechnology Initiative.”

In explaining the Clinton administration’s visionary 2001 spending requests for nanotech research and development (R&D), then-OSTP Director Neal F. Lane, the president’s assistant for science and technology, said: “Nanotechnology thrives from modern advances in chemistry, physics, biology, engineering, medical, and materials research, and will contribute to cross-disciplinary training of the 21st century science and technology workforce. The administration believes that nanotechnology will have a profound impact on our economy and society in the early 21st century, perhaps comparable to that of information technology or of cellular, genetic and molecular biology.”

Military Nano Spies
As the world enters the second decade of the 21st century, nanotech research has exploded across nearly every aspect of modern life, from computers and communications to medicine and agriculture. In one form or another, in varying degrees, there is little that does not face significant change from the evolution – if not revolution – in nanotechnology.

That is especially true for the military, where potential applications of nanotechnology and nanotech-based ISR, guidance and tracking, identification friend or foe (IFF), “smart” weapons, scaled lethality, homeland and combat zone security, communications, combat medicine, prosthetics, and so on are poised to forever change virtually every aspect of military life, TTPs (tactics, techniques, and procedures), and Conops (concept of operations).

A nanomachine (nanobot, nanoid, nanite, nanomite, etc.) is not, when completed, necessarily of nano size (most range from 0.1 to 10 micrometers), but comprise nano-scale components to give it power and capabilities far beyond what size alone might imply. A suite of nanotech-based devices, in fact, could be comparatively large and vital to the operation of equipment as big as a B-2 bomber or Abrams main battle tank. As nanotech continues to shrink the size of components used in such equipment, designers will face the option of reducing the size of the final components or platform or retaining its old size while packing it with significantly more – and better – sensors, computers, weapons, etc.

Among the host of possibilities for military nanotech are miniaturized ISR applications known as “smart sand” or “smart dust.” These can be configured as electronic noses (e-nose) the size of a grain of sand, able to analyze the immediate environment, identify chemical compositions, and report to a monitoring system. The end report can be quite comprehensive, combining data from thousands of e-noses, each sampling a sensor bubble only a few inches in diameter but, in tandem, covering an area limited only by the number of available nanobots – or, in this case perhaps, nanodots.

If a smart sand network incorporated a range of sensor types, the monitoring computer to which each reports could use data fusion to build a complex and accurate real-time picture of what is happening in that remote field or mountain path, without an enemy ever knowing it was there and with zero risk to local civilians.

In a July 2010 paper for the American Chemical Society, an international research team from the United States, Russia, Germany, and Italy described how they successfully built a nanobelt – an individual wedge-like tin dioxide nanowire – to mimic, even potentially exceed, the capabilities of the mammalian olfactory system.

“The proposed approach represents the combined bottom-up/top-down technologically viable route to develop robust and sensitive analytical systems scalable down to submicrometer dimensions,” according to the abstract for their paper, “Single-Nanobelt Electronic Nose: Engineering and Tests of the Simplest Analytical Element.”

According to team member Dr. Andrei Kolmakov, an associate professor of physics at Southern Illinois University, integrating the main sensor, power source, and data transmission capability into a single nanostructure is comparable to the development of integrated electronics in place of a combination of individual component circuits.

Nanobots Take Flight
In recent years, the military has employed a number of mostly hand-launched micro-UAVs in Southwest Asia and elsewhere. While those platforms – such as the Switchblade, Wasp, Anubis, Raven, etc. – do not fall into the nano category, they and future MAVs are certain to benefit from the evolution of nanosensors.

However, the Defense Advanced Research Projects Agency (DARPA) and industry also have been working on a new class of NAV (nano-UAVs) closer in size to insects. One variety, called an ornithopter, actually employs insect-like flapping wings. Others are essentially tiny helicopters.

In a lecture at the Naval Postgraduate School, Dr. Siva Banda, senior scientist for control theory with the Air Force Research Laboratory (AFRL) Air Vehicles Directorate, described the purpose and value of “fly on the wall” NAVs that “are unobtrusive, evasive and lethal, inexpensive but capable, able to rapidly respond, are persistent and have insect-like maneuverability.”

“The greatest constraint and number one challenge – more than control – is vehicle propulsion, finding a way to pack more and more onboard power into smaller and smaller batteries. With current power sources, we can only fly small UAVs for a few minutes, where we need to be able to operate them for hours,” he said. “[Another] major challenge is achieving controlled stable flight in flapping wing models.

“It’s hard to make bio-mimetic MAVs that are highly maneuverable, like birds and insects, within the constraints of hovering, limited power, and light weight. This requires the development of highly complex algorithms and miniaturizing greater and greater onboard information processing capability. By 2015, we want to be able to build bird-size mini-UAVs with WMD [weapon of mass destruction] sensing capabilities. And by 2030 – a very ambitious goal – to have insect-size micro-UAVs with WMD sensing, tracking, and targeting capabilities that can operate alone or in swarms in contested environments against intelligent adversaries.”

An application of such platforms is being studied at the University of Pennsylvania in a program called Scalable sWarms of Autonomous Robots and Mobile Sensors (SWARMS). Bringing together experts in artificial intelligence (AI), control theory, robotics, systems engineering, and the biology of swarming behavior in nature, the goal of SWARMS is to adapt bio-inspired swarming behavior to engineered systems, according to professor Vijay Kumar.

“We will be interested in such questions as: Can large numbers of autonomously functioning vehicles be reliably deployed in the form of a ‘swarm’ to carry out a prescribed mission and to respond as a group to high-level management commands? Can such a group successfully function in a potentially hostile environment, without a designated leader, with limited communications between its members, and/or with different and potentially dynamically changing ‘roles’ for its members?” Kumar wrote in his project description.

“What can we learn about how to organize these teams from biological groupings, such as insect swarms, bird flocks and fish schools? Is there a hierarchy of ‘compatible’ models appropriate to swarming/schooling/flocking which is rich enough to explain these behaviors at various resolutions, ranging from aggregate characterizations of emergent behavior to detailed descriptions which model individual vehicle dynamics?”

The variety of such nanotech devices under investigation at university labs – in the United States, around the world, and collaboratively – barely demonstrates the potential of nanotech. Those include:

Self-Healing Metals – Nano-structured materials, up to 10 times stronger than aluminum alloys, designed to “self-heal” cracks, bullet holes, etc.; being researched under a $1.2 million Army grant by the University of Wisconsin-Milwaukee.

Nubots (nucleic acid robots) – Synthetic nanoscale devices such as “DNA walkers” involved in separate research efforts at NYU, CalTech, Duke, Purdue, and Oxford.

Positional Nanoassembly – The focus of 23 researchers from 10 organizations in four nations to develop positionally controlled diamond mechanosynthesis, including a diamondoid nanofactory capable of building diamondoid medical nanobots.

Snake-inspired Robots – While most of the focus for military systems has been on those that fly, hover, crawl, hop, walk, etc., another area in which nanotech may provide significant advancement is “body undulation,” the method of locomotion used by snakes. Researchers at the University of Maryland, for example, believe such an approach “may offer significant benefits over typical legged or wheeled locomotion designs in certain types of scenarios.” As with any attempt to mimic nature, an undulating robot offers many challenges, but nanoservers, nanohydraulics, nanopower sources, and nanosensors – all built into a robot from the size of a large snake indigenous to the combat zone to one as small as an earthworm – offer significant advantages to warfighters, especially special operations forces.

Open Nanobiotech – Following the use of open-source architectures that have helped accelerate computer system development, a similar approach to nanotech has been proposed to the United Nations as a way to accelerate nanorobotic development to the benefit of society at large. Establishing nanobiotechnology as a “human heritage” for future generations, using open technology based on ethical practices, could speed its peaceful development, according to proponents. At the same time, the military has adapted open-architecture designs to speed the addition and implementation of new capabilities into legacy platforms, an approach that would greatly increase the speed with which nanotech could be employed across a wide range of military systems and devices.

Nanobot Race – Just as the Space Race of the 1960s and ’70s between the United States and the USSR sped the development of technologies from computers to microwaves to ceramics, a new global race to develop nanotech capabilities could significantly increase the speed – and variety – of such efforts.

U.S. industry, in particular, already is working hard, individually and cooperatively, to advance nanotech across a wide range of potential applications; the medical community is proposing ways to apply nanotech to a host of medical treatments and procedures; government grants totaling billions of dollars are encouraging universities and research labs in developing new nanotech capabilities; and financial institutions are making strategic investments in such research in the hope of acquiring rights and royalties from future nanobot commercialization.

A Google search for “nanotech patent” returns more than 1 million results, indicative of the speed and scope of nanotechnology R&D. Early applications already include ISR sensors, targeted drug-delivery systems, biomedical surgical instruments, altering the nature of both pharmacokinetics (what the body does to a drug), and pharmacodynamics (what a drug does to the body).

In future medical applications, non-replicating nanobots will be injected into a patient’s body to work at the cellular level to repair or prevent damage. While that capability remains theoretical, the speed at which nanotech is advancing could put it into the hands of doctors within a generation. Such rapid, cellular-level treatment could have obvious benefits in dealing with warfighter wounds in the field, treating indigenous populations, even aiding in the capture, health maintenance, and interrogation of enemy personnel.

Other Military Nano-apps
One of the biggest problems facing today’s ground warrior is having enough batteries and charge capability to complete a mission of indeterminate length – a problem compounded by the requirement to bring back all dead batteries rather than dispose of them in the field.

In 2010, researchers at Ohio-based Nanotek Instruments Inc. unveiled a graphene-based supercapacitor that broke all storage and recharge records. According to project leader Bor Jang, the device can store as much energy as a nickel metal hydride battery but recharge in a matter of seconds. In addition, its specific energy density comprises the highest energy values ever reported for a nano-carbon-based “electric double layer” supercapacitor.

Researchers also are hard at work on nanoscopic assemblers – essentially nanobots that can create and maintain non-woven textiles for use as lightweight personal armor. Not only would such fabrics, embedded with active nanobots, be self-repairing in the field, they also could provide a platform for medical nanobots that could track the wearer’s vital signs, seal wounds, and react to changes in the weather, transforming from porous to nonporous as needed to heat or cool the warfighter. Such materials would be lighter, stronger, fire-retardant, resistant to chemical, biological, and radiological weapons, water repellent, and moisture absorbent.

With active nanobots present throughout the combat uniform, variations also could be incorporated to power the warfighter’s equipment – itself lighter and more versatile thanks to nanotech. Those might include intrasquad and long-range communications; helmet-based video displays; enough data storage to meet any mission (or personal) requirement; and special vision enhancements for telescopic, microscopic, infrared, and full color spectrum “sight,” etc. That also could include integration with external sensors, such as smart sand, insect-size UAVs/UGVs (unmanned ground vehicles), etc., along with data fusion to give the warfighter a real-time situational awareness critical to both mission success and personal survival.

Meanwhile, DARPA is looking into how nanotechnology may provide the necessary breakthrough capabilities to make true AI a reality. According to Kurzweilian futurist Brian L. Wang, a member of the Center for Responsible Nanotechnology Task Force and the Nanoethics Group Advisory Board, that may be closer to reality than most believe.

If the key to true AI is to replicate the human brain, which has about 100 billion neurons and 100 trillion synapses, then nanotech is the essential enabling technology. And key to that is the memristor, what Wang terms a novel circuit element with a property base that, while insignificant on a microscale, is substantial at the nanoscale. Bearing mathematical similarities to the behavior of brain neurons, memristors are central to DARPA’s Modular Neural Exploring Traveling Agent (MoNETA) project to mimic, on a chip, how neurons process information in the brain.

A corresponding DARPA project called SyNAPSE (Systems of Neuromorphic Adaptive Plastic Scalable Electronics) would provide the electronic equivalent of the brain’s neurons and synapses, with memristors contributing faster memory and computational capability, possibly to the AI level. Even so, DARPA’s most ambitious public goals would only be 2 percent as energy efficient as the human brain.

The future of nanotechnology is impossible to predict, in terms of scope and potential applications, for both military and civilian applications. What is known was summarized by professor Nitin Chopra, head of the Nanomaterials Processing Group at the University of Alabama, in his paper on “Development of Next Generation Nanoscale Heterostructures”:

“Owing to their diverse functionality, high surface-to-volume ratio and unique size-dependent properties, nanostructures are of immense importance for chemical and biological sensors, medical devices, catalysts, photovoltaics and nanodevices. A wide range of material choices, coupled with different synthetic strategies, result in different morphological versions, such as nanometer-scale thin films, nanowires, nanotubes, nanobelts, nanoparticles, and nanoporous structures.

“These kinds of multifunctional and multicomponent hierarchical heterostructures are extremely useful and will definitely impact our lives in many ways, from automobiles to nanoelectronics. The challenge is to take them to the next level of innovation, which we are consistently striving for.”

This article first appeared in The Year in Defense: Review Edition, Winter 2011.