As large, fast-moving, and heavily armed behemoths, tanks are the primary offensive weapon of modern armies. And for the past 100 years, engineers have been locked in an arms race to protect their own tanks and kill others. Typically, protecting tanks has consisted of adding new, increasingly heavy armor plating. But kinetic active protection systems, such as the Russian ARENA system in this video, are growing increasingly popular.
Over the past century, the average weight of tanks has quadrupled. One of the first tanks, “Little Willie”, weighed in at 16.5 tons; the modern American M1 Abrams weighs approximately 70. Most of that weight is armor, and as effective as that’s been to keep tanks alive, it comes at a cost in size, weight, speed, and mobility. Over the long term, increasing a tank’s size and weight is unsustainable.
In the 1970s the armies of NATO fielded a new generation of anti-tank missiles. The Soviet Union, to protect its investment in a numerically superior tank force, began researching countermeasures. One was the concept of the active protection system, or APS.
APS involves ringing a tank with sensors, typically millimetric wave radars set up to detect incoming rockets and missiles along the tank’s frontal arc. Once an incoming anti-tank round is close enough, the APS launches an interceptor rocket to take out the incoming rocket or missile. Active protection systems are lightweight, effective, and cost less than adding more armor to a tank.