--- title: "Explosive Reactive Armor: How ERA Works" description: "For more than a hundred years, the tank has been a formidable symbol of military might. From the Blitzkrieg to the Gulf War all the way to Ukraine, the ability to effectively counter formations of enemy armored vehicles has often been the deciding factor between victory and defeat.\n\nAnd so, over the years, anti-tank weapons have evolved alongside the vehicles themselves, beginning as humble bolt-action rifles with enough power to penetrate a tank's armor, all the way to today's shoulder-fired anti-tank missiles that guide themselves to the target after launch. Likewise, in a classic arms race of predator and prey, tank designs have continually added better and better defenses to keep these dangers at bay: smaller interceptor rockets, electronic warfare, even lasers to disrupt an incoming missile's guidance system.\n\nBut there will inevitably come a time when these defenses fail, and an enemy warhead reaches and strikes the tank. When that happens, not all hope is lost. Thanks to explosive reactive armor, the tank, and the crew inside, still have a good chance to brush off the impact with little to no damage. Here we dive into the science of how explosive reactive armor works, its current and future variants, and how militaries around the world are designing cutting-edge weapons to overcome it.\n\n## How to Fight Fire with Fire\n\nThe basic concept behind explosive reactive armor, or ERA, is quite simple. While the specifics vary across the globe, most variants share the same core layout of three layers: an outer metal plate, underneath which sits a highly explosive element, followed by an inner metal plate. The way this volatile sandwich saves a tank from certain doom begins from the moment an enemy missile makes contact.\n\nWhen the ERA module detects sufficient pressure on the outer metal plate, the explosive filling detonates, pushing the metal layers in opposite directions. This explosion is far smaller than that of the anti-tank warhead it's up against, but it doesn't need to be immensely powerful to get the job done. It isn't trying to outright destroy the threat on its own; it just needs to disrupt it.\n\nThat disruption comes from two effects. The first is physical damage, done not just by the blast but by the metal plates launched as the module is ripped apart. The length of the warhead must come into contact with all of these metal fragments and cut through the moving layers as it tries to reach the tank's actual armor, which slows the missile and deforms its specially shaped tip. The second effect comes from the blast and moving plates directly disrupting the missile's trajectory, since the modules are usually placed at an angle on the outside of the tank. Forcing the projectile onto a slightly altered path makes it far less likely that the anti-tank charge will have enough energy to punch through.\n\nIf everything works properly, an incoming missile loses momentum, has its shape damaged, and is steered slightly off course. This can result in the missile detonating prematurely before making true contact, or detonating on contact, both of which can be easily absorbed.\n\nThere are a few deviations from the standard design, such as one that uses numerous banana-shaped rods with individually packed explosives, but the key concept is the same. Even if the enemy warhead still manages to explode with all its might, it won't have much effect on the tank or its crew, because it was unable to penetrate the thick armor.\n\n## Always Ready, and Scalable\n\nEven surviving the first shot can be the difference between life and death on the battlefield. Imagine an armored convoy ambushed by hidden guerilla fighters who suddenly launch a shoulder-fired anti-tank rocket at the lead vehicle. Because ERA requires no active scanning or electronics to function, and is always at the ready, even a surprise attack like this can be absorbed with zero action from the crew inside, allowing the tank to immediately return fire and get to a safer location.\n\nThe other advantage of ERA is that it can be scaled to the threats a tank is expected to face. If the enemy is expected to fire long, kinetic-energy projectiles, versions with significantly thicker plates and higher explosive yield can be equipped. Modules can also be focused only on certain parts of a vehicle depending on where threats are expected, such as the front or the sides.\n\nAfter its invention and deployment in the late 70s and early 80s, ERA saw combat in a few conflicts and was adopted by many militaries worldwide. But it was the USSR that took a special liking to the concept. Soviet production of ERA modules was so widespread that kits were retroactively designed even for older tanks such as the T-55, giving them a rapid modernization without much investment of time or money. Today, explosive reactive armor is still highly valued by eastern European militaries, with widespread deployment of the ERA known as Kontakt-1 and Kontakt-5 on T-72s and T-80s, and newer Russian modules designed specifically for the T-90 and T-14 Armata. It's also regularly used by armored vehicles of the Israeli Defense Force, and comes equipped on US Abrams tanks as part of the Tank Urban Survival Kit, with the tiles heavily focused on the left and right sides of the Abrams.\n\nAs time has gone on, ERA modules have been improved not just by making them thicker or heavier, but by speeding up their reaction time. The sooner the filling can explode upon contact, the further the plates will travel, causing even more disruption to the incoming charge as it now has to cover more space while in constant contact with the moving metal plates.\n\n## The Drawbacks\n\nOn paper, it sounds like ERA, especially combined with other forms of defense, is near unstoppable. That's far from the truth. In reality there are several disadvantages to the counter-explosive concept.\n\nLet's start with the obvious: the explosion. Even in a perfect, ideal scenario where the enemy missile is completely neutralized, amounting to just slamming into the side of the tank, the ERA module's own explosion still poses a danger to anyone standing near the vehicle. This is due to the fragmenting metal plates, which can be lethal to someone too close. Because of this, infantry has to maintain a safe distance from vehicles using explosive reactive armor. To be fair, without the ERA, the blast from a high-explosive warhead striking the tank would also be dangerous to anyone nearby.\n\nERA is also quite heavy. A full set of bricks around a tank adds several tons to its overall weight, forcing a crew to somewhat compromise mobility for safety.\n\nThe next shortcoming is that ERA plates provide no protection against certain sizes of smaller projectiles. A lot of information on this topic can be found in a paper titled \"Criteria and evaluation of ballistic sensitivity of explosive reactive armor,\" written by Serbian researcher Marinko Ugrčić. Through extensive testing and theoretical analysis, he found that small-arms fire did not trigger the ERA plate, which is intended, but that 20mm and 30mm armor-piercing or incendiary ammunition often did trigger detonation. The real danger here is that an encounter with a smaller vehicle, one that normally wouldn't pose such a grave threat, can shred your reactive armor with its smaller rounds, leaving you vulnerable until the armor is replaced. This size of ammunition, between 20 and 30mm, is commonplace on the battlefield, used by the autocannon on the A-10 Warthog and even the Bradley Fighting Vehicle.\n\nBut the true danger to ERA is the tandem charge, a type of projectile designed with two separate warheads. The precursor warhead, located at the tip of the rocket, strikes the reactive armor and goes through everything described earlier: the metal plates disrupt its momentum, the blast alters its course, and so on. But remember, explosive reactive armor can only be used once. Now that it's been compromised by the first charge, the second plows through into its target uninterrupted, at full speed, and at the proper trajectory.\n\nIf they hit correctly, tandem charges can all but nullify explosive reactive armor. And this isn't just hypothetical, as it has been seen time and time again on the ground in Ukraine, especially during the first months when Western anti-tank rockets were mopping the floor with Russian tanks regardless of how many ERA bricks were in use. This is why you may have seen photos of Russian tanks with metal cages on top; these were believed to be an added layer of defense against tandem charges, but they ultimately aren't all that helpful.\n\n## Reactive Armor Variants\n\nWhile it's certainly the flashiest, ERA isn't the only type of reactive armor.\n\nThere's also its opposite, non-explosive reactive armor, also called non-energetic reactive armor, or NERA. Just like ERA, the non-explosive versions are built with two metal plates and a filling between them, only instead of an explosive element, the filling is an elastic material such as rubber, plastic, or specially designed foams.\n\nYou might be wondering how a layer of rubber could possibly stop a rocket. The answer is that it uses the incoming warhead's own energy against it. When a charge hits the front plate, it generates a shockwave that travels through the deeper layers. As that shockwave leaves the metal layer and enters the rubber, it refracts, or changes its angle, just as light does when it goes from traveling in air to water. The shockwave reverberates through the rubber, and as it exits into the back metal plate, it refracts into a new direction once again. This sudden force causes the back metal plate to rapidly move in the direction of the shockwave, which by this point is a completely different direction than the one the missile is traveling in. As a result, the warhead's trajectory is altered as it encounters this rapidly moving back plate, preventing it from penetrating the tank's armor.\n\nNERA has a few advantages over the explosive versions. For starters, it's far cheaper, making it easier to produce in large quantities. But the real treat is that because they don't blow themselves up as part of their design, they can remain functional even after being hit. This multi-hit capability makes them more effective against tandem charges, ERA's critical weakness.\n\nThat's why in some videos of captured and dismantled Russian tanks, they're often found employing explosive reactive armor on the front and sides while the reactive armor on top is filled with non-explosive variants, since the top of the tank is where the Javelin anti-tank missile, and its tandem charge, are most likely to strike.\n\n## The Next Game-Changer: Electric Armor\n\nAs the arms race of anti-tank weapons and their countermeasures presses forward, there is one innovation that could change the whole game. This is electric armor. Instead of using explosives or rubber to fill the gap between the two plates, it uses nothing, leaving the gap filled with air. The two separate plates are connected to a high-voltage power source, turning the whole system into a capacitor. When an incoming projectile penetrates through the first layer and touches the second, it closes the circuit and discharges the energy of the capacitor onto the projectile. With enough energy involved, this could completely annihilate or vaporize the projectile entirely, or, according to some estimates, even turn it into plasma.\n\nElectric reactive armor has some significant advantages over its traditional counterparts. It would be far lighter, allowing it to be placed over the entirety of the vehicle without sacrificing as much speed or mobility. Because it doesn't explode, it would also eliminate the shrapnel issue found in ERA, meaning supporting infantry could remain close to the vehicle. And it would have multi-hit capability, since the only requirement for its continued function is a power source and a projectile closing the circuit.\n\nIts main disadvantage is that, well, it hasn't really been invented yet. There are some prototypes out there, with the UK and the US testing several variants, some of which have allegedly performed quite well, but the expense of further testing and deployment has kept it from becoming mainstream. The other concern is that while it sounds cool, it might not actually be significantly more useful than ERA with our current capabilities, as it requires a lot of energy to fully vaporize larger projectiles, perhaps more than we can reliably produce and sustain with current technology. These issues are the primary reason electric reactive armor, despite its potential, is still many years from widespread deployment, and why ERA remains the king of rolling with the anti-tank punches.\n\n## Key Takeaways\n\n- Explosive reactive armor (ERA) is a three-layer sandwich, an outer metal plate, an explosive filling, and an inner metal plate, that detonates outward to disrupt an incoming warhead rather than destroy it.\n- ERA needs no electronics or active scanning, so it protects instantly even against surprise ambushes, and it can be scaled with thicker plates or focused on specific parts of a vehicle.\n- The Soviet Union embraced ERA most fully, retrofitting kits onto tanks as old as the T-55 and fielding Kontakt-1 and Kontakt-5 across its fleet.\n- ERA's drawbacks include lethal fragmentation to nearby infantry, several tons of added weight, vulnerability to 20–30mm autocannon fire, and a single-use design that tandem charges can defeat.\n- Non-explosive reactive armor (NERA) trades the explosive for an elastic filling, gaining lower cost and multi-hit capability that resists tandem charges.\n- Electric armor, still in prototype testing, promises a lighter, shrapnel-free, multi-hit defense, but high energy demands and cost keep it years from widespread use.\n\n## Frequently Asked Questions\n\n### How does explosive reactive armor actually stop a missile?\n\nWhen a warhead strikes the outer plate, the ERA module detonates its explosive filling, throwing the metal plates apart. The warhead is forced to cut through the moving fragments, which slows it and deforms its shaped tip, while the angled blast nudges it off course. The result is a missile that has lost momentum and trajectory and can no longer penetrate the tank's armor.\n\n### Why doesn't ERA need to be as powerful as the warhead it's stopping?\n\nERA isn't trying to destroy the incoming threat outright; it only needs to disrupt it. By damaging the warhead's shape, slowing it, and altering its path, the much smaller ERA blast prevents the anti-tank charge from delivering enough energy to break through. The missile often detonates prematurely or on contact, where the tank's armor can absorb it.\n\n### What are tandem charges, and why are they so dangerous to ERA?\n\nA tandem charge is a projectile with two separate warheads. The first, precursor warhead triggers and is disrupted by the reactive armor, but since ERA can only be used once, the second warhead then plows through uninterrupted at full speed and proper trajectory. As seen repeatedly in Ukraine, well-aimed tandem charges can all but nullify explosive reactive armor.\n\n### How is non-explosive reactive armor different from ERA?\n\nNERA uses the same two-plate layout but replaces the explosive with an elastic filling like rubber, plastic, or foam. A warhead's shockwave refracts through the filling and rapidly moves the back plate in a new direction, altering the warhead's path. Because it doesn't destroy itself, NERA is cheaper and can survive multiple hits, making it better suited to resisting tandem charges.\n\n### What is electric armor and why isn't it in use yet?\n\nElectric armor leaves an air gap between two plates wired to a high-voltage power source, turning them into a capacitor. A projectile penetrating the first plate and touching the second closes the circuit, discharging energy that could vaporize the projectile or even turn it to plasma. It would be lighter, shrapnel-free, and multi-hit capable, but it remains in prototype testing because of high energy demands and cost.\n\n### Can small-caliber fire defeat explosive reactive armor?\n\nYes, to a degree. Research by Serbian engineer Marinko Ugrčić found that small-arms fire doesn't trigger ERA, but 20mm and 30mm armor-piercing or incendiary rounds often do. That means weapons like the A-10 Warthog's autocannon or a Bradley Fighting Vehicle can shred a tank's reactive armor, leaving it exposed until the bricks are replaced.\n\n## Sources\n\n- [Original MegaProjects video: Explosive Reactive Armor: Fighting Explosions with Explosions](https://www.youtube.com/watch?v=2z3o2NOdq1o)\n- [Reactive armour — Wikipedia](https://en.wikipedia.org/wiki/Reactive_armour)\n- [Kontakt-5 — Wikipedia](https://en.wikipedia.org/wiki/Kontakt-5)\n- \"Criteria and evaluation of ballistic sensitivity of explosive reactive armor\" — Marinko Ugrčić, *Scientific-Technical Review* (2004)\n\n- [Hero image source](https://commons.wikimedia.org/wiki/File:T72_Georgia.jpg) by 1st Lt. Justin Colvin / U.S. Marine Corps, public domain.\n\n## Related Coverage\n\n- [How Close Is Active Camouflage?](/article/how-close-is-active-camouflage)\n\n- [Kugelpanzer: The Most Bizarre Tank of World War II](/article/kugelpanzer-bizarre-wwii-tank)" url: https://megaprojects.pub/article/explosive-reactive-armor-fighting-explosions-with-explosions.md canonical: https://megaprojects.pub/article/explosive-reactive-armor-fighting-explosions-with-explosions datePublished: 2026-06-09 dateModified: 2026-06-09 author: - name: Simon Whistler url: https://megaprojects.pub/author/simon-whistler publisher: MegaProjects image: "https://media.megaprojects.pub/cdn-cgi/image/width=600,height=338,fit=cover,quality=80,format=auto/articles/2z3o2NOdq1o/hero.jpg" type: NewsArticle contentHash: 6998e77536628bd56ca9c1968437534d9a9a3f8d979168ef9b4f623c85b673a4 tokens: 4315 summaryUrl: https://megaprojects.pub/article/explosive-reactive-armor-fighting-explosions-with-explosions.md.summary.md --- For more than a hundred years, the tank has been a formidable symbol of military might. From the Blitzkrieg to the Gulf War all the way to Ukraine, the ability to effectively counter formations of enemy armored vehicles has often been the deciding factor between victory and defeat. And so, over the years, anti-tank weapons have evolved alongside the vehicles themselves, beginning as humble bolt-action rifles with enough power to penetrate a tank's armor, all the way to today's shoulder-fired anti-tank missiles that guide themselves to the target after launch. Likewise, in a classic arms race of predator and prey, tank designs have continually added better and better defenses to keep these dangers at bay: smaller interceptor rockets, electronic warfare, even lasers to disrupt an incoming missile's guidance system. But there will inevitably come a time when these defenses fail, and an enemy warhead reaches and strikes the tank. When that happens, not all hope is lost. Thanks to explosive reactive armor, the tank, and the crew inside, still have a good chance to brush off the impact with little to no damage. Here we dive into the science of how explosive reactive armor works, its current and future variants, and how militaries around the world are designing cutting-edge weapons to overcome it. ## How to Fight Fire with Fire The basic concept behind explosive reactive armor, or ERA, is quite simple. While the specifics vary across the globe, most variants share the same core layout of three layers: an outer metal plate, underneath which sits a highly explosive element, followed by an inner metal plate. The way this volatile sandwich saves a tank from certain doom begins from the moment an enemy missile makes contact. When the ERA module detects sufficient pressure on the outer metal plate, the explosive filling detonates, pushing the metal layers in opposite directions. This explosion is far smaller than that of the anti-tank warhead it's up against, but it doesn't need to be immensely powerful to get the job done. It isn't trying to outright destroy the threat on its own; it just needs to disrupt it. That disruption comes from two effects. The first is physical damage, done not just by the blast but by the metal plates launched as the module is ripped apart. The length of the warhead must come into contact with all of these metal fragments and cut through the moving layers as it tries to reach the tank's actual armor, which slows the missile and deforms its specially shaped tip. The second effect comes from the blast and moving plates directly disrupting the missile's trajectory, since the modules are usually placed at an angle on the outside of the tank. Forcing the projectile onto a slightly altered path makes it far less likely that the anti-tank charge will have enough energy to punch through. If everything works properly, an incoming missile loses momentum, has its shape damaged, and is steered slightly off course. This can result in the missile detonating prematurely before making true contact, or detonating on contact, both of which can be easily absorbed. There are a few deviations from the standard design, such as one that uses numerous banana-shaped rods with individually packed explosives, but the key concept is the same. Even if the enemy warhead still manages to explode with all its might, it won't have much effect on the tank or its crew, because it was unable to penetrate the thick armor. ## Always Ready, and Scalable Even surviving the first shot can be the difference between life and death on the battlefield. Imagine an armored convoy ambushed by hidden guerilla fighters who suddenly launch a shoulder-fired anti-tank rocket at the lead vehicle. Because ERA requires no active scanning or electronics to function, and is always at the ready, even a surprise attack like this can be absorbed with zero action from the crew inside, allowing the tank to immediately return fire and get to a safer location. The other advantage of ERA is that it can be scaled to the threats a tank is expected to face. If the enemy is expected to fire long, kinetic-energy projectiles, versions with significantly thicker plates and higher explosive yield can be equipped. Modules can also be focused only on certain parts of a vehicle depending on where threats are expected, such as the front or the sides. After its invention and deployment in the late 70s and early 80s, ERA saw combat in a few conflicts and was adopted by many militaries worldwide. But it was the USSR that took a special liking to the concept. Soviet production of ERA modules was so widespread that kits were retroactively designed even for older tanks such as the T-55, giving them a rapid modernization without much investment of time or money. Today, explosive reactive armor is still highly valued by eastern European militaries, with widespread deployment of the ERA known as Kontakt-1 and Kontakt-5 on T-72s and T-80s, and newer Russian modules designed specifically for the T-90 and T-14 Armata. It's also regularly used by armored vehicles of the Israeli Defense Force, and comes equipped on US Abrams tanks as part of the Tank Urban Survival Kit, with the tiles heavily focused on the left and right sides of the Abrams. As time has gone on, ERA modules have been improved not just by making them thicker or heavier, but by speeding up their reaction time. The sooner the filling can explode upon contact, the further the plates will travel, causing even more disruption to the incoming charge as it now has to cover more space while in constant contact with the moving metal plates. ## The Drawbacks On paper, it sounds like ERA, especially combined with other forms of defense, is near unstoppable. That's far from the truth. In reality there are several disadvantages to the counter-explosive concept. Let's start with the obvious: the explosion. Even in a perfect, ideal scenario where the enemy missile is completely neutralized, amounting to just slamming into the side of the tank, the ERA module's own explosion still poses a danger to anyone standing near the vehicle. This is due to the fragmenting metal plates, which can be lethal to someone too close. Because of this, infantry has to maintain a safe distance from vehicles using explosive reactive armor. To be fair, without the ERA, the blast from a high-explosive warhead striking the tank would also be dangerous to anyone nearby. ERA is also quite heavy. A full set of bricks around a tank adds several tons to its overall weight, forcing a crew to somewhat compromise mobility for safety. The next shortcoming is that ERA plates provide no protection against certain sizes of smaller projectiles. A lot of information on this topic can be found in a paper titled "Criteria and evaluation of ballistic sensitivity of explosive reactive armor," written by Serbian researcher Marinko Ugrčić. Through extensive testing and theoretical analysis, he found that small-arms fire did not trigger the ERA plate, which is intended, but that 20mm and 30mm armor-piercing or incendiary ammunition often did trigger detonation. The real danger here is that an encounter with a smaller vehicle, one that normally wouldn't pose such a grave threat, can shred your reactive armor with its smaller rounds, leaving you vulnerable until the armor is replaced. This size of ammunition, between 20 and 30mm, is commonplace on the battlefield, used by the autocannon on the A-10 Warthog and even the Bradley Fighting Vehicle. But the true danger to ERA is the tandem charge, a type of projectile designed with two separate warheads. The precursor warhead, located at the tip of the rocket, strikes the reactive armor and goes through everything described earlier: the metal plates disrupt its momentum, the blast alters its course, and so on. But remember, explosive reactive armor can only be used once. Now that it's been compromised by the first charge, the second plows through into its target uninterrupted, at full speed, and at the proper trajectory. If they hit correctly, tandem charges can all but nullify explosive reactive armor. And this isn't just hypothetical, as it has been seen time and time again on the ground in Ukraine, especially during the first months when Western anti-tank rockets were mopping the floor with Russian tanks regardless of how many ERA bricks were in use. This is why you may have seen photos of Russian tanks with metal cages on top; these were believed to be an added layer of defense against tandem charges, but they ultimately aren't all that helpful. ## Reactive Armor Variants While it's certainly the flashiest, ERA isn't the only type of reactive armor. There's also its opposite, non-explosive reactive armor, also called non-energetic reactive armor, or NERA. Just like ERA, the non-explosive versions are built with two metal plates and a filling between them, only instead of an explosive element, the filling is an elastic material such as rubber, plastic, or specially designed foams. You might be wondering how a layer of rubber could possibly stop a rocket. The answer is that it uses the incoming warhead's own energy against it. When a charge hits the front plate, it generates a shockwave that travels through the deeper layers. As that shockwave leaves the metal layer and enters the rubber, it refracts, or changes its angle, just as light does when it goes from traveling in air to water. The shockwave reverberates through the rubber, and as it exits into the back metal plate, it refracts into a new direction once again. This sudden force causes the back metal plate to rapidly move in the direction of the shockwave, which by this point is a completely different direction than the one the missile is traveling in. As a result, the warhead's trajectory is altered as it encounters this rapidly moving back plate, preventing it from penetrating the tank's armor. NERA has a few advantages over the explosive versions. For starters, it's far cheaper, making it easier to produce in large quantities. But the real treat is that because they don't blow themselves up as part of their design, they can remain functional even after being hit. This multi-hit capability makes them more effective against tandem charges, ERA's critical weakness. That's why in some videos of captured and dismantled Russian tanks, they're often found employing explosive reactive armor on the front and sides while the reactive armor on top is filled with non-explosive variants, since the top of the tank is where the Javelin anti-tank missile, and its tandem charge, are most likely to strike. ## The Next Game-Changer: Electric Armor As the arms race of anti-tank weapons and their countermeasures presses forward, there is one innovation that could change the whole game. This is electric armor. Instead of using explosives or rubber to fill the gap between the two plates, it uses nothing, leaving the gap filled with air. The two separate plates are connected to a high-voltage power source, turning the whole system into a capacitor. When an incoming projectile penetrates through the first layer and touches the second, it closes the circuit and discharges the energy of the capacitor onto the projectile. With enough energy involved, this could completely annihilate or vaporize the projectile entirely, or, according to some estimates, even turn it into plasma. Electric reactive armor has some significant advantages over its traditional counterparts. It would be far lighter, allowing it to be placed over the entirety of the vehicle without sacrificing as much speed or mobility. Because it doesn't explode, it would also eliminate the shrapnel issue found in ERA, meaning supporting infantry could remain close to the vehicle. And it would have multi-hit capability, since the only requirement for its continued function is a power source and a projectile closing the circuit. Its main disadvantage is that, well, it hasn't really been invented yet. There are some prototypes out there, with the UK and the US testing several variants, some of which have allegedly performed quite well, but the expense of further testing and deployment has kept it from becoming mainstream. The other concern is that while it sounds cool, it might not actually be significantly more useful than ERA with our current capabilities, as it requires a lot of energy to fully vaporize larger projectiles, perhaps more than we can reliably produce and sustain with current technology. These issues are the primary reason electric reactive armor, despite its potential, is still many years from widespread deployment, and why ERA remains the king of rolling with the anti-tank punches. ## Key Takeaways - Explosive reactive armor (ERA) is a three-layer sandwich, an outer metal plate, an explosive filling, and an inner metal plate, that detonates outward to disrupt an incoming warhead rather than destroy it. - ERA needs no electronics or active scanning, so it protects instantly even against surprise ambushes, and it can be scaled with thicker plates or focused on specific parts of a vehicle. - The Soviet Union embraced ERA most fully, retrofitting kits onto tanks as old as the T-55 and fielding Kontakt-1 and Kontakt-5 across its fleet. - ERA's drawbacks include lethal fragmentation to nearby infantry, several tons of added weight, vulnerability to 20–30mm autocannon fire, and a single-use design that tandem charges can defeat. - Non-explosive reactive armor (NERA) trades the explosive for an elastic filling, gaining lower cost and multi-hit capability that resists tandem charges. - Electric armor, still in prototype testing, promises a lighter, shrapnel-free, multi-hit defense, but high energy demands and cost keep it years from widespread use. ## Frequently Asked Questions ### How does explosive reactive armor actually stop a missile? When a warhead strikes the outer plate, the ERA module detonates its explosive filling, throwing the metal plates apart. The warhead is forced to cut through the moving fragments, which slows it and deforms its shaped tip, while the angled blast nudges it off course. The result is a missile that has lost momentum and trajectory and can no longer penetrate the tank's armor. ### Why doesn't ERA need to be as powerful as the warhead it's stopping? ERA isn't trying to destroy the incoming threat outright; it only needs to disrupt it. By damaging the warhead's shape, slowing it, and altering its path, the much smaller ERA blast prevents the anti-tank charge from delivering enough energy to break through. The missile often detonates prematurely or on contact, where the tank's armor can absorb it. ### What are tandem charges, and why are they so dangerous to ERA? A tandem charge is a projectile with two separate warheads. The first, precursor warhead triggers and is disrupted by the reactive armor, but since ERA can only be used once, the second warhead then plows through uninterrupted at full speed and proper trajectory. As seen repeatedly in Ukraine, well-aimed tandem charges can all but nullify explosive reactive armor. ### How is non-explosive reactive armor different from ERA? NERA uses the same two-plate layout but replaces the explosive with an elastic filling like rubber, plastic, or foam. A warhead's shockwave refracts through the filling and rapidly moves the back plate in a new direction, altering the warhead's path. Because it doesn't destroy itself, NERA is cheaper and can survive multiple hits, making it better suited to resisting tandem charges. ### What is electric armor and why isn't it in use yet? Electric armor leaves an air gap between two plates wired to a high-voltage power source, turning them into a capacitor. A projectile penetrating the first plate and touching the second closes the circuit, discharging energy that could vaporize the projectile or even turn it to plasma. It would be lighter, shrapnel-free, and multi-hit capable, but it remains in prototype testing because of high energy demands and cost. ### Can small-caliber fire defeat explosive reactive armor? Yes, to a degree. Research by Serbian engineer Marinko Ugrčić found that small-arms fire doesn't trigger ERA, but 20mm and 30mm armor-piercing or incendiary rounds often do. That means weapons like the A-10 Warthog's autocannon or a Bradley Fighting Vehicle can shred a tank's reactive armor, leaving it exposed until the bricks are replaced. ## Sources - [Original MegaProjects video: Explosive Reactive Armor: Fighting Explosions with Explosions](https://www.youtube.com/watch?v=2z3o2NOdq1o) - [Reactive armour — Wikipedia](https://en.wikipedia.org/wiki/Reactive_armour) - [Kontakt-5 — Wikipedia](https://en.wikipedia.org/wiki/Kontakt-5) - "Criteria and evaluation of ballistic sensitivity of explosive reactive armor" — Marinko Ugrčić, *Scientific-Technical Review* (2004) - [Hero image source](https://commons.wikimedia.org/wiki/File:T72_Georgia.jpg) by 1st Lt. Justin Colvin / U.S. Marine Corps, public domain. ## Related Coverage - [How Close Is Active Camouflage?](/article/how-close-is-active-camouflage) - [Kugelpanzer: The Most Bizarre Tank of World War II](/article/kugelpanzer-bizarre-wwii-tank)