The basic idea of reactive, explosive armor is to explode when an incoming round strikes the tank. The explosion either redirects the actual incoming round, or damages it, making it ineffective.  

    The better forms of explosive reactive armor can either break or bend a penetrator, protecting the tank. Reactive armor has to be designed so that when it explodes it does not cause injury or death to nearby infantry or to other vehicles. (A similar consideration applies to hard-kill active defense systems – see below.)

    The British, Germans and, especially the US long thought that their main battle tanks, designed in the 1970s and 1980s were good against most threats and did not require reactive (explosive) armor. 

    If US and German armor could be knocked out with older ammunition using explosively formed penetrators (in the US best known as shaped charge weapons) and not DART ammunition, it was easy to see that Western tanks were at risk. The Russians immediately recognized the vulnerability of Leopard tanks to Russian antitank weapons.

    Starting in 2017 the US army designed what it called Angled Tiles, a type of reactive armor designed to deflect an incoming threat, either upwards or downwards (depending on how the tiles are configured on installation). By 2019 the US Army started installing Angled Tiles on US Abrams tanks deployed in Europe, admitting that America’s top tank, despite its super secret armor, was deficient in protection. 

    This is especially significant since the newest US Abrams main battle tanks have a unique layered armor system that is said to include depleted uranium. The US decided not to provide this tank version with depleted uranium-enhanced armor to Ukraine fearing the Russians might copy it, but it is the most advanced version getting Layered Tiles. Ukraine is not getting layered tiles either.

    Meanwhile, in Ukraine, the recently arriving Leopard tanks are being modified by the addition of external reactive armor. Lacking their own sources for reactive armor, the Ukrainians are pulling modules off of damaged or destroyed Russian tanks. So far at least, the modified Leopard 2 tanks are being fitted with Kontakt 1 reactive armor, at least a few generations behind the latest protective reactive armor systems.

    The haste with which Ukraine is plastering its “new” Western tanks with reactive armor tells us something else: these new tanks are not much better than what they had before. And it tells us, furthermore, that even better ones held back by the Pentagon don’t cut it.

    An Active Defense System is a system that destroys incoming mortars, rockets and shells before they hit a tank. The system works by detecting the incoming threat and neutralizing it by firing an explosively formed projectile.

    An Active Defense System is at its best against antitank weapons and mortars. It is less capable against tank-fired ammunition because these rounds travel at supersonic (nearly Mach 3) speeds. 

    Thus proper tank defenses need to have top-quality armor, reactive armor and Active Defense Systems. Tanks with all three capabilities can potentially survive against even a well-equipped and heavily armed adversary.

    There are a number of Active Defense Systems around, and some newer ones under development apparently will use lasers instead of explosively formed projectiles. 

    The Russians claim to have one or more active defense systems (one of them is called Arena), but not a single Russian tank in the Ukraine war is equipped with Active Defense. None of the tanks being delivered by Germany, the UK and the US are fitted with Active Defense.  

    The best of the currently-deployed systems is the Israeli Trophy (Rafael) and a newer type made in Israel called Iron First (Israel Military Industries). Trophy has been proven in combat and is fitted to Merkava tanks. 

    Some 100 or so units have been sold to the Pentagon for the Abrams main battle tank, but that’s a drop in the bucket. Some Bradley Infantry Fighting Vehicles are being equipped with Iron Fist, but not those supplied to Ukraine.

    Just as US forces have paltry air defenses because they refused to buy Israel’s Iron Dome air defense system, the same is true for US tanks, where only a small number of systems were purchased for trials. The Pentagon has long been rightly accused of suffering from the Not Invented Here (NIH) syndrome.

    Other Abrams tanks have been fitted with a so-called Soft-Kill Active Defense System that is supposed to jam the electronics of a threat. Since kinetic weapons fired by tanks or artillery guns don’t use much in the way of electronics, soft kills offer no help. 

    Soft kill may be effective against troop-operated antitank weapons. It is unlikely any soft kill system will be on the Abrams tanks delivered to Ukraine.

    Unfortunately, we won’t see how properly equipped Western tanks might perform in the Ukraine war. And it is increasingly likely that plenty of the main battle tanks from Europe and the United States will go up in smoke, along with their crews.