Sci-Fito Reality: the Defense Technologies of the Future

The imagination of science fiction has inspired many technological developments, most notably the cellular phone. However, not many fields have been more heavily influenced by sci-fi than the field of military technology. Currently, some of the most exciting technologies taken straight from sci-fi that are being developed are ALON (transparent aluminum), electric reactive armor (shields), and laser systems (phasers).The military of the future may beidentical to the science fiction of today.

Introduction:

Remember watching Star Trek for the first time? Was there anything cooler than exploring the galaxy in a spaceship, meeting and fighting with all sorts of alien species? When Star Trek first aired in 1966, it depicted a utopian future in which humanity had overcome all internal strife and constructed a society consisting of many species working together to explore and learn. However, because the series’ core concept is the exploration of the unknown, threats are encountered in the form of hostile species and unexplained phenomena. To deterand solve problems,various technologies, including military technologies designed for protectionwere emphasized.

Amazingly, many of the imagined technologies of the television series have now been realized–at least to some extent–or are currently being developed.The most common invention attributed to Star Trek is the cell phone, based on the hand held communicator used by the crew of the Enterprise. In this article, however, the focus is placed on military technologies. Many of the Enterprise’s defensive and offensive ability, such as its protective transparent aluminum armor and shield systems, as well as its “phaser” weaponry systems, are the source of inspiration for many systems currently being developed by the US military. These technologies may be implemented in the next generation of aircraft and naval vessels in both defensive and offensive roles.

Transparent Aluminum:

In Star Wars and Star Trek, there are numerous mentions of fictitious transparent versions of materials stronger than glass that are used in the design of vehicles (transparent steel and transparent aluminum to just name a few). An exciting development taken directly fromStar Trek and Star Wars that may drastically increase the protection and safety of military vehicles is transparent aluminum, known as aluminum oxynitride (ALON), pictured below in Figure 1.On most military vehicles, the weakest points are the windows, which utilize bulletproof glass. Bulletproof glass is a combination of both hard and flexible types of glass, able to absorb the energy of most bullets. However, in order to provide full protection, glass of at least almost 3.5 inches can be needed [1].

Figure 1. Near complete transparency of ALON being demonstrated

ALON armor, as presented in Figure 2, on the other hand is twice as strong and half the weight of a comparable bulletproof glass panel.It may, therefore, be able to further protect soldiers from battlefield threats, specifically IEDs (Improvised Explosive Devices) that claimed many lives in the Iraq and Afghanistan wars.Additionally, 1 in of ALON is able to provide protection against.50-caliber ammunition, which is able to penetrate more than 2 in of bulletproof glass[2]. In fact, its increased hardness makes ALON attractive to the military for many more reasons than just increased protection. As presented in Wahl, the transparent armor with ALON as the outer layer proved more scratch resistant and durable under environmental stress than traditional bulletproof glass in field test. [1]

Figure 2. Comparison between ALON and Bulletproof Glass

How it Works:

In order to create ALON, the process of sintering is used. Sintering is the process of creating a solidified material from prepared powders using heat and pressure. In sintering, the material never enters a liquid state, but is formed to a mold by pressure and baked by the heat [3]. For ALON, the powders used for the sintering process are aluminum oxide (Al2O3) and aluminum nitride (AlN).The powders are then mixed in a ratio of 67.5 mole percent aluminum Oxide and 33.5 mole percent aluminum Nitride [3]. Once the powder mixture is complete, it is then shaped in the desired mold and undergoes the sintering process in a nitrogen atmosphere. As can be seen in Figure 3, in order to generate acceptable transparent ALON, high temperatures, approaching ALON’s melting point of about 2100 degrees Fahrenheit are needed. If temperatures are not significantly high enough, the aluminum oxynitride willcontain small grains that dissipate light, causing the material to be opaque. It was found that at a minimum temperature of 1800 degrees Celsius acceptably transparent ALON,with sufficiently large grains, is produced[3].

Figure 3. Microstructures of ALON at varying temperatures

Limitations:

While ALON has been proven to possess the attributes needed in a bulletproof glass replacement, there are still some reasons that have prevented it from being implemented in military vehicles. The two main reasons are the cost of manufacture and restrictions on the thickness of produced ALON. Currently the cost of ALON per in2 is around $10-15 for material around 1/8 inthick, 5 times that of the currently used bulletproof glass [4].Until costs can be reduced, ALON will not be a viable replacement.

More limitations are that ALON cannot be produced in sizes sufficient to serve as a windshield or in diverse shapes to suit other needs. Currently, manufacture is limited to sheets of around 25x40 inches, enough for windows, but not windshields [1]. Fortunately, these limitations will likely be remedied as time passes and improved methods of mass manufacture drive costs down and allow for greater freedom in the shape and thickness of produced ALON.

Shields (Or Electric Reactive Armor):

While ALON is a material directly from Star Trekthat might increase the protection of vehicles’ viewports, electric reactive armor is an invention oft compared to sci-fi “shields” that might increase the protection received by the rest of the vehicle. Currently, most tanks and other military vehicles have armor plating multiple inches thick. This armor plating reduces the performance of the vehicle overalland doesn’t provide protection from all categories of projectiles. Armor plating is generally unable to provide protection from weapons known as shape charges. Shape charges work by directing a high-velocity jet of metal that is able to penetrate much greater thicknesses of armor than conventional rounds and destroy everything inside of the vehicle. As a result of the devastating destructive power of these weapons, the current and next generation of armor technology has largely been focused on mitigating the effects of and defending against shape charges.

Currently, the category of armor known as reactive armor has provideddefense against shape charges [5]. The most common form of reactive armor is explosive reactive armor. Explosive reactive armor generally consists of high explosive placed between two metal plates as illustrated in Figure 4.When attacked by a penetrating weapon, the explosive detonates, driving the metal plates apart, disrupting and deflecting the penetrating agent. However, one clear limitation of this explosive armor is that it cannot be reused. Many governments, but mainly the United States and the European Union, have been experimenting with electric reactive armor as a reusable replacement for explosive reactive armor [6].

Figure 4. Explosive reactive armor and how it functions

How it works:

Electric reactive armor consists of at least two metal plates, each of which is separated by an insulating material [6]. This creates an extremely high-power capacitor with an extremely powerful electric field. As illustrated in Figure 5, when charged by a high-voltage source and struck by an incoming projectile, the energy of the capacitor and the field is discharged into the projectile. This discharge causes an immense amount of energy to flow into the projectile, which may vaporize it or cause it to become plasma, significantly reducing the penetrating power of the attack [5]. The fact that the invisible electric field plays a critical role in the functioning of the armor and serves as almost a “force field” causes electric armor to be compared to the shields of Star Trek.

Figure 5. Electric Armor broken down

Limitations:

While the concept of electric reactive armor is deceptively simple, it currently has many limiting factors that may reduce its effectiveness. The largest limitation of the armor is that it requires time to recharge after every discharge [6].This is still an improvement over explosive reactive armor, as it can be reused, but the vehicle would be vulnerable until recharged. Currently, electric reactive armor is considered to be unreliable, as it is difficult to get working under even laboratory conditions. As a result, the wear and tear of battlefield environments could easily cause the electric armor to malfunction unless strides are made to increase its reliability. Despite these limitations, electric armor shows promise. If it can be coupled with other defensive systems, such as high-energy lasers and traditional armor, an effective shield against both shape charges and conventional projectiles could be created.

Laser Weaponry:

The system that currently has the most defensive (and potentially offensive) promise consists of high-energy lasers.While ALON and electric armor will protect vehicles from projectile impact, a laser defense system would prevent the impacts themselves, drastically increasing safety. Because the laser beam is made up of light and therefore travels at the speed of light, high-energy lasers can provide a near instantaneous defense against projectile weapons that move at relatively slow speeds. Eventually, given increases in the power of laser weaponry, the weapons may eventually be able to destroy aircraft, vehicles, and the ICBMs (Inter-Continental Ballistic Missiles) that are the delivery vehicle of choice for the majority of nuclear weapons [7]. If the potential of laser weaponry can be realized, defensive networks could be constructed that render current nuclear weapon delivery systems obsolete, thereby neutralizing our ability to destroy our own species and civilization through nuclear war.

How it works:

The physics behind how a laser works is fairly simple; it is simply a device that emits lightin a coherent beam. Unlike a flashlight in which light is scattered in many directions, the light from a laser is focused and directed as exemplified in Figure 5. This means that the beam from a laser stays narrow and that all of the energy of the laser is transferred to the single spot the laser hits as opposed to a flashlight, which scatters its energy over the area it illuminates.The difficulty in constructing a laser lies in producing the coherent beam. There are many different types of lasers, but they all operate on the same physical principles.

Figure 5. Comparison of light patterns between flashlight and laser

To construct a laser, a controlled, enclosed medium (gas, liquid, solid, plasma) is needed [8]. This medium is pumped with intense flashes of light or electrical discharges to move the electrons of the atoms of the medium into an excited, higher energy state. However, the electrons do not stay at the excited energy levels, they prefer lower energy levels. To reach the lower levels, the electrons must release energy. As explained in Apruzese, this energy is released in the form of photons or light [8]. If the composition of the medium is uniform, or restricted to just a couple elements, the light released possess specific, identical wavelengths. More simply, two identical atoms with electrons in identical states will release photons with identical wavelengths. If these identical atoms encounter atoms with electrons in the same excited state, stimulated emission can occur. In other words, the first photon can stimulate emission of more identical photons that possess the same frequency and direction. When this process is placed between two mirrors, a cascading effect occurs causing more laser light to be emitted. One of these mirrors is “half-silvered”, meaning that it allows some light through while reflecting the rest [8]. The light that makes it through forms the laser beam.

But how do lasers function as weapons? How are they able to penetrate and destroy targets? How do lasers compare to conventional weapons? When high-energy lasers hit their targets, energy is transferred. This energy transfer causes the affected area to instantaneously heat and expand, which damages the target [8].Laser and other directed-energy weapon systems have large advantages over conventional systems. The cost of firing a laser system can be very inexpensive because only electrical energy is needed to fire the system. This differs from conventional rounds, which can cost thousands of dollars per rounddue to the materials and guidance technologies in the round [9]. If these systems can be perfected, not only will they revolutionize warfare, but they will also make military forces cheaper and more flexible when it comes to dealing with unknown threats.

Limitations:

The problem with constructing lasers that can serve as weapon platforms is maintaining the power of larger laser systems while compressing it into as usable size that can fit onto military platforms [8]. The first military laser system, designed by the US to be able to defeat ICBMs, was based on a modified Boeing 747 aircraft due to its size. However, the US military has since developed the system pictured in Figure 6., which can be mounted onto ships. In the future, as laser systems become smaller and more powerful, they could potentially be mounted onto aircraft and vehiclesin anti-vehicular and anti-personnel roles.

Figure 6. Military laser system currently in field trials

Conclusion:

The future of military forces may look astonishingly close to what was imagined by Gene Roddenberry in 1966. Impressive advances have been made toward many technologies once exclusively found in science fiction. In the future, terms like “energy shields”, “lasers”, and “transparent aluminum” that were once exclusively seen in sci-fi novels, television shows, and movies may be a part of every day conversation.These technologies are improving the protection of soldiers while also improving the performance of the vehicle. This is different from the past, where greater protection meant more material, or weight, added to the vehicle, which increases drag and reduces maneuverability. The military design process of tomorrow may not be subject to the same constraints as the military design process of today.

References:

[1]J. M. Wahl et al. Recent advances in ALON optical ceramic. Surmet. USA. [Online] Available: WHITE-PAPER-Recent-Advances-in-ALON(TM)-Optical-Ceramic.pdf

[2]S. Ashley. (2006, May 15). Enhanced Armor.Scientific American [Online]. Available:

[3]J. Cheng et al. (2000, May 5). Microwave sintering to fully transparent aluminum oxynitride (ALON) ceramics. Journal of Materials Science Letters [Online]. 20 (2001). 77-79. Available:

[4]S. Ashley. (2006, May 15). Enhanced Armor.Scientific American [Online].Available:

[5] S. Knoeller. Protecting the Warfighter-Recent Armor Innovations. AMMTIAC Quaterly [Online]. Volume 4 (No. 4). Available:

[6] P. Zheng et al. Research on the Passive Electromagnetic Armor. IEEE Transactions on Magnetics [Online]. Volume 41 (No. 1). Available:

[7] R. Bagnell. High Energy Liquid Laser Area Defense System (HELLADS). DARPA. USA. [Online] Available: _Area_Defense_System_(HELLADS).aspx

[8]J. Apruzese et al. Ar-Xe Laser: The Path to a Robust, All-Electric Shipboard Directed Energy Weapon. WSTIAC Quarterly [Online]. Volume 9 (No. 2). Available:

[9]L. Martinez. Army’s New Laser Weapon Can Shoot Down Mortars and Drones. ABCNews. USA. [Online]. Available: shoot-down-mortars-and-drones/