On Dec. 12, 2001, in the early days of the war in Afghanistan, U.S. Special Forces led an attack on Tora Bora, a mountainous warren of caves and bunkers on the country’s eastern border.
Their target? Osama bin Laden.
Tracking down the world's most wanted man is hard enough in unfamiliar territory, let alone when his supporters put up a furious fight. And a battlefield like this -- cramped, mountainous, and frigid at night -- had distinct challenges. For one, the rugged terrain and caves threw shadows and darkness where only steps before there had been sunlight and blue sky.
For most of us, moving from shade to sunlight poses little more inconvenience than putting on a pair of sunglasses. But for a soldier, especially one clearing a bunker complex, every second is precious, every blink of the eye the possible difference between killing or being killed. In other words, changing glasses is an ill-afforded luxury.
The U.S. Army Soldier Systems Center in Natick, Mass., exists to develop technology to react to -- and in some cases anticipate -- these special circumstances. One of its most important tasks is to relieve soldiers of their many burdens, like the inability to swap a pair of glasses or the necessity of carrying 150 pounds of gear.
Its goal: keep troops comfortable, in communication and -- ultimately -- alive.
Among the most promising approaches to accomplishing this task is nanotechnology, the study and manipulation of individual atoms and molecules. With it, researchers hope to develop materials that perform better than their conventional counterparts, improving a soldier’s mobility and safety.
Scientists have long appreciated the possibility of working at nanoscale, but it was largely impossible until 1981, with the creation of a microscope capable of viewing individual atoms. At nanoscale (one-billionth the size of a base unit of measurement, e.g. a nanometer is one-billionth of a meter), a substance can be engineered to have more surface area to bond with other materials. As you slice something into increasingly smaller pieces, its total surface area increases, exposing an increasing proportion of its atoms to chemical reactions with another material.
It's like slicing an apple, but into a billion pieces and not just six: more of its flesh will brown as compounds in its exposed tissue react with oxygen in the air around it.
By exploiting this phenomenon -- the surface area bit, not the browning -- scientists hope to integrate potentially life-saving technology into military uniforms and equipment while doing away with the unwanted heft and bulk brought on by macro-scale upgrades. At nanoscale, some molecular arrangements bestow distinct material advantages: greater strength, lighter weight, more control over the light spectrum and higher levels of chemical reactivity.
In 2002, the U.S. military indicated deepening interest in the technology with the establishment of the Army-funded Institute for Soldier Nanotechnologies at the Massachusetts Institute of Technology. At the Soldier Systems Center in Natick, scientists have been researching nanotechnologies for at least the past 10 to 15 years, said Dr. Lynne Samuelson, its chief scientist.
“We’re not necessarily creating technologies, but modifying them slightly and using them in new ways,” she said.
After years of research, some of these advances are ready to make their way to the battlefield.
The future of combat
When you drive through the campus of the Soldier Systems Center, the cutting edge is the furthest thing from the mind. It’s housed in a complex of cinderblock buildings with all the charm and outward technological sophistication of a 1970s-era public high school. Don't let its appearance fool you. The basic research conducted here can have profound implications for combat soldiers -- and, in some cases, the rest of us, too.
Dr. Francisco Aranda, a research physicist, has been working with a team to address the problems soldiers face in rapidly changing light conditions. A technology is needed to rapidly darken in response to bright light, such as the sun. Commercially-available lenses that fade to dark in sunshine are far too slow for combat conditions, so the team has been working to create a new lens technology -- light-sensitive dyes -- that change color faster than the human eye reacts to light, in about 200 milliseconds.
The researcher's first set of new lenses faded much faster, but they were still not quick enough. Then, by adding a small amount of nanotubes that interact strongly with light, the scientists were able to shorten the transition time further, by about a factor of two. The new technology could be used for next-generation lenses and should be field-ready in about four years, Aranda said.
On a recent afternoon in the lab, Aranda showed me a pair of goggles meant to react to lasers -- ubiquitous on the battlefield, whether from bystanders pointing hand-held pointers as a distraction or from machine gun scopes used to line up bullets-in-waiting. Currently, when a laser beam connects with an Army-issued goggle, the entire lens fills with light.
Wielding a flashlight, Aranda demonstrated how the nanotechnology his team is working on contains the beam to a single point, rather than allowing it to disperse across a soldier’s field of vision. As he waved the light in front of the goggles, a nano-coating on the lens reacted instantaneously, creating small, square pixels -- similar to the flashing cursor on an early personal computer -- that block the beam.
But this technology is years away from battlefield use, if it is deployed at all. Such uncertainty is at the heart of research at the lab. They call it "six-one" -- basic research, the type of open-ended scientific inquiry that can lead to breakthrough discoveries, incremental advancement or, at times, nothing at all.
For the U.S. Army, the usual predicate for such research is a request from the officers and soldiers in the field. The scientists at Natick take those requests, conceive a possible scientific solution and present a proposal to chief scientist Samuelson and a panel of reviewers. The research proceeds with that original goal in mind, but often takes an unexpected path.
For instance, a team of scientists is working to modify the "optical signature" of nanocrystalline zinc oxide by pairing it with other nanomaterials. Zinc oxide appears white to the naked eye, but it can change colors when it's paired with other nanomaterials and viewed with a special light. The scientists thought the material might be helpful in preventing “friendly fire” accidents -- the coating could be applied to a uniform and, when viewed with a sensor, identify a U.S. soldier.
But on further study, they concluded that the light is too difficult to detect at a distance. “Everything shouldn’t be a success,” Samuelson said. “Then you’re really not pushing the limits.”
The discovery still holds promise, however. The ability to tailor that color change makes the substance useful as a method for identification for different lots of materials and supplies. For example, today's parachutes are stenciled with a manufacture date or "in-service" date, which is used to determine when it's no longer safe to use. (The service life of canopies and subcomponents ranges from 20 to 35 years).
But those stencils fade with age. A durable, "scannable" zinc-oxide coating with a specific light signature could be used to determine parachute age instead -- and could ultimately be used for supply chain management elsewhere, both for the Army and in private industry.
Getting Army green
Sometimes nanotechnology is tapped to provide a safer alternative to a proven solution with unwanted side effects. When the U.S. Army learned the hard way about unwelcome side effects of some conventionally manufactured chemicals and materials, it changed course.
"The Army is pushing this stuff," research biologist Robert Stote said. "In the past, it was, 'Just get it done.' But some of those things were making soldiers sick."
Stote is working on biological, or "green," nanomaterials to defend against traditional viruses and bacteria, as well as chemical and biological weapons. By incorporating antimicrobial agents into combat uniforms, he hopes to reduce the need for soldiers to carry over-the-counter hand gels and wipes. Aside from the bulk of such items, the challenging conditions in which soldiers operate makes an integrated, "always on" solution much more desirable.
“A lot of environments we put soldiers in are not safe” from a disease standpoint, Stote said. “We don’t have the immunities that the natives have.”
Under such conditions, a simple scratch can lead to an infection that sidelines a soldier for days. And even if the wound heals quickly, the medications needed to treat it could prevent a soldier from operating machinery or weapons for much longer.
Other possible uses of the nano-oxides are to create materials that "self-decontaminate" when in contact with chemical or biological weapons, or at least repel such weapons in liquid form. Stote plans to focus his future research on bacteriocins, which target and kill specific bacteria types rather than the "carpet bombing" effect of current antimicrobials, which kill everything, good or bad.
Stote is not alone in his endeavors. Other research teams at Natick are working on fire retardants, of particular importance given the prevalence of improvised explosive devices on battlefields in Iraq and Afghanistan. A testing lab at its center can replicate the 1,200-degree temperature heat that's typically produced by an IED's initial blast.
So far, much of the nanotechnology in the labs has yet to be tested in the field. Research, of course, is not for the impatient. That's particularly so for military-related science.
For instance, once Aranda determines that his laser-blocking material works as intended, the technology must then be tested to make sure it functions in accordance with all other military requirements for battlefield goggles, such as ballistic protection. If the coating fails to work with materials that prevent explosive debris from penetrating the lens then, well, it’s of no use.
At Natick and elsewhere, years of painstaking research and development that results in a scientific breakthrough may ultimately yield little, other than potential commercial application. But it’s the rigorous testing and steep requirements that make resulting products emerge from the center of unassailable quality, Samuelson said.
“If you can do it here," she said, "you can do it anywhere.”