In a scene from the 1987 film Predator, the main character, Dutch (played by Arnold Schwarzenegger), finds himself covered in mud on a riverbank as the manhunting alien stares directly at him. Fortunately for Dutch, the cool mud covering his skin matches the temperature of the surrounding dirt, masking from the predator’s thermal vision the heat radiating from his body. More than 30 years later, the need to mask from enemy sensors the thermal signatures of Marines in the field is urgent.
Whether facing state or nonstate actors, the Marine Corps in future wars will be required to contend with a technologically sophisticated enemy. On battlefields around the globe, current and potential U.S. adversaries have demonstrated an impressive ability to employ sophisticated unmanned aerial systems (UASs) and advanced ground systems. In ongoing and future wars, Marines should not assume that the airspace and electromagnetic spectrum will be as uncontested as they have been throughout the wars in Iraq and Afghanistan.
Enemy UAS platforms and other technologies equipped with advanced sensors will make Marines’ ability to avoid detection increasingly difficult. Traditional camouflage methods to conceal Marines in the visible spectrum still will be essential, but Marines also will need to be invisible in the infrared (IR) spectrum. IR sensors employed from a UAS are especially concerning, because they can be fielded by state militaries or easily acquired commercially by nonstate actors. Marines currently have no good countermeasure to stay hidden from an IR sensor.
The IR threat demands a countermeasure that can be used by individuals in the field. The average infantryman’s load already is heavy, so such technology would need to be lightweight, man-portable, and easy to use. The recent development and testing of an IR-cloaking material may offer one solution.
Black Silicon IR Cloaking
Scientists at the University of Wisconsin recently developed and patented a material that, in testing, was able to mask up to 94 percent of the IR radiation given off by a person’s body heat.1 The black silicon material was tested using sheets less than one millimeter thick. Present in the fabric are millions of tiny nano-wires—essentially microscopic needles. When IR waves hit this cloth, rather than being reflected or absorbed by it, they “bounce” around between the nanowires, becoming trapped inside.2
methods to conceal
Marines in the visible
spectrum still will
be essential, but
Marines also will need
to be invisible in the
Testing on similar thermal blankets revealed that the material eventually heats up as it stays in contact with a person’s body. Thus, these blankets can mask the IR signature from body heat for only a short period. The black silicon material, however, has small air pockets built into it, which allow heat to disperse and prevent the cloth from warming up.
A Marine could cover his or her body or fighting position in a blanket of black silicon material when an enemy UAS or other thermal sensor was present, trapping the heat radiated from the body inside the fiber’s nanowires. This could be employed for a long time, such as when Marines are in defensive positions, because the air pockets would disperse the heat and allow the material to remain blended with the thermal signature of the surroundings. The fabric could be especially useful at night or in low-light conditions, which limit the enemy’s sight in the visible spectrum and force him to use thermal optics.
Another potential use of such a material is to conceal stationary vehicles or small pieces of critical infrastructure, such as generators or command posts. In testing, the silicon masked the IR signature of vehicles as well as humans. More detailed information on the material and the study is not yet publicly available, so it is difficult to determine whether it will meet all the requirements of infantry Marines. However, it does offer hope that a lightweight and effective IR countermeasure is possible.
Of note, BAE Systems is developing a system using another technology called ADAPTIV, which camouflages vehicles from thermal imaging. The system employs hexagonal plates that can quickly be cooled or heated to blend in with the surrounding temperature. In addition to becoming “invisible” to thermal optics, the system can make armored vehicles take on the appearance of civilian vehicles, cows, bushes, or rocks.3 While a technology such as ADAPTIV offers some promise in concealing vehicles from thermal imaging, its weight and power requirements preclude its use for dismounted troops.
“Space blankets” are commonly included in first aid kits. When wrapped around a person, they reflect heat back rather than letting it escape into the surrounding air. Just as with black silicon sheets, if a Marine is covered with a space blanket, most of the thermal radiation from the body reflects off the blanket, making it more difficult for IR sensors to detect the person (there is even a YouTube video of an Apache helicopter’s forward-looking infrared sensor being defeated by a space blanket).4 Not all thermal radiation is reflected by space blankets, however, and when in contact with a body, the blanket eventually warms up enough to be detectable by thermal sensors. Space blankets also are typically made of shiny material, although the outer surface could be modified with a camouflage pattern without reducing the heat-reflectiveness of the underside. However, current space-blanket technology is likely not a reliable countermeasure to advanced IR sensors, but with some experimentation and field testing, a modified space blanket may prove to be a low-cost solution.
Camouflage for the Future
The black silicon developed by the University of Wisconsin team may or may not be the right solution to the problem of IR camouflage, but its performance in testing offers promise that a lightweight, man-portable, easily employed material can be fielded in the near future. It is important to note that its use is limited to the IR spectrum. Signatures from cell phones, radios, and other communications equipment still could make Marines vulnerable to detection in other frequencies of the electromagnetic spectrum. But when it comes to IR countermeasures, with the right research and development, the Marine Corps will be able to field the appropriate technology before it finds itself in the same situation as Dutch, faced down by the predator in a Central American jungle.
1. Sam Million-Weaver, “‘Stealth’ Material’ Hides Hot Objects from Infrared Eyes,” University of Wisconsin-Madison News, 21 June 2018.
2. Million-Weaver, “‘Stealth’ Material.”
3. BAE Systems, “ADAPTIV: A Unique Camouflage System,” BAE website.
4. YouTube, “Apache vs. Space Blanket,” 16 November 2015.