Russian military forces have over 700 different types of nuclear weapon “carriers” – strategic bombers, nuclear submarines and intercontinental ballistic missile silos.

But, little do people know that some of them can operate autonomously and strike potential enemy targets, even if the whole country’s territory is destroyed after a nuclear strike.

This system is called the ‘Dead Hand’. But how does it work?

This system can automatically send hundreds of nukes to an enemy without a command from a human.

The ‘Perimeter’ system, dubbed in the United States and Europe the ‘Dead Hand’, is an automatic control system for a retaliation nuclear strike.

To put it simply, if Russia’s territory is devastated after a nuclear attack, the Perimeter system automatically strikes the enemy’s territory with its own nuclear missiles.

Russia currently has an estimated 1,600 deployed tactical nuclear weapons, with another 2,400 strategic nuclear weapons tied to intercontinental ballistic missiles. This makes Russia the largest nuclear power in the world. All of these weapons are tied into the Perimeter, an automatic nuclear weapons control system.

In a crisis that might mean a first strike from the United States, high-ranking government officials or military commanders could activate the Perimeter. Perimeter would guarantee that the Soviet Union (and now, Russia) could respond even if its entire armed forces were wiped out.

Once switched on, the Perimeter system can launch the entire Russian nuclear arsenal in response to a nuclear attack. It was part of the Cold War doctrine of mutually assured destruction, a means of deterring nuclear attacks by ensuring the side who initiated a first strike also would be annihilated.

Called “Dead Hand” in the West, the theory is that a command and control system measures communications on military frequencies, radiation levels, air pressure, heat and short-term seismic disturbances. If the measurement points to a nuclear attack, the Perimeter begins a sequence that would end in the firing of all ICBMs in the Soviet (now, Russian) arsenal.

Perimeter would launch a command rocket, tipped with a radio warhead that transmits launch orders to Russian nuclear silos, even with the presence of radio jamming. The rocket would fly across the entire length of the country. After a number of test launches to prove the viability of such a command rocket, the Perimeter system went online in 1985.

In the United States, similar technologies were developed. Seismic and radiation sensors are used to monitor parts of the U.S. and the world for nuclear explosions and other activity, but the U.S. military never created an automatic trigger for its arsenal. Instead, it ensured that American humans with the ability and authority to launch a second strike would survive a first strike.