During the Cold War, both sides developed highly effective electronic countermeasures for enemy combat control. Therefore, it was extremely necessary to create a system that would guarantee the delivery of combat orders issued by the highest levels of command (General Staff of the USSR Armed Forces, General Staff of the Strategic Missile Forces) to command posts and strategic missile launchers that were on alert. There was also the likelihood of the defeat of command posts, in the event of the enemy's first nuclear strike. In the process of design work, the idea arose of using a special rocket with a powerful radio transmitting device as a backup communication channel. It could be launched in the event of suppression of the controls. This rocket could give launch commands to all missiles on alert on the territory of the USSR.
The main purpose of the 15E601 "Perimeter" system was the control of a nuclear retaliatory strike and guaranteed delivery of combat orders to individual command posts, launchers, strategic aircraft on alert, in case of impossibility to use the existing communication lines.
The system used a sophisticated sensor system to measure seismic activity, air pressure and radiation. This was to make it possible to determine whether a nuclear strike was carried out in order to ensure the possibility of a nuclear retaliatory strike without using the "red button". In the event of the disappearance of communication with the air defense and the establishment of the fact of the attack, the procedure for launching missiles would be brought into action, which would allow the USSR to strike back after its own destruction.
The autonomous command and control system being developed was to have the ability to analyze changes in the global military and political environment in order to evaluate the commands that were received over a certain period of time. Based on this, it was concluded that something went wrong in the world. If the system considered that its time had come, then the procedure for preparing the missile launch was initiated.
At the same time, active hostilities were not supposed to begin in peacetime, even in the absence of communication or the departure of the entire combat crew from the BSP or command post posts. The system had to have additional parameters blocking its operation. Along with the above-described extreme algorithm of operation, the system had intermediate modes.
The Yuzhnoye Design Bureau was commissioned to develop a special command system. On August 30, 1974, the government of the USSR signed the corresponding decree N695-227.
Later, the government set another task - to expand the set of functions that the command missile complex solved in order to bring combat orders to strategic missile boats, command posts of the Air Force, Navy and Strategic Missile Forces, naval and long-range missile-carrying aircraft.
It was originally planned that the MR-UR100 (15A15) rocket would become the base, but later it was replaced by the MR-UR100 UTTKh (15A16) rocket. After revising the control system, it was assigned the index 15A11.
In December 1975, a preliminary design of a control rocket was presented. A special warhead with the index 15B99 was installed on it, which included an original radio engineering system developed by the LPI Design Bureau. To provide the necessary conditions for the operation, the warhead needed a constant orientation in space.
To aim the missile in azimuth, a completely autonomous system with an automatic gyrocompass and a quantum optical gyrometer was used. This system could calculate the primary azimuth for the base direction in the process of placing the missile on alert, store it during alert duty, even in the event of a nuclear impact on the launcher.
On December 26, 1979, the first successful launch of a command rocket with an installed transmitter equivalent took place. The testing of complex algorithms for pairing all the system nodes that took part in the launch was carried out, as well as checking the ability of the 15B99 head part to adhere to a given flight trajectory - the top of the trajectory was at an altitude of about 4000 m with a flight range of 4500 km.
In the course of various tests of the "Perimeter" system, real launches of various missiles that were in service with the Strategic Missile Forces took place, with the help of orders transmitted by the SGCH 15B99. Additional antennas and receivers were installed on the launchers of these missiles. Subsequently, these improvements affected all launchers and command posts of the Strategic Missile Forces.
Ground checks were carried out on the territory of the Kharkov Institute of Physics and Technology, the Novaya Zemlya nuclear test site and in the VNIIEF test laboratories in the city of Arzamas. Here they checked the performance of the entire complex under the influence of the damaging factors of a nuclear strike. As a result of testing, the operability of the hardware complex of the control system and the CGS was confirmed under a nuclear impact exceeding that specified in the TTT MO.
All work on the command rocket was completed by March 1982. And in January 1985, the complex took up combat duty. After that, command-staff exercises were periodically held, in which the 15E601 "Perimeter" system participated.
In November 1984, the 15A11 command missile was launched. After the 15B99 warhead entered the passive trajectory, a command was given to launch the 15A14 rocket (R-36M, RS-20A, SS-18 "Satan") from the NIIP-5 test site at the Baikonur cosmodrome. The launch took place in the normal mode: after working out all the rocket stages, a hit on the target was recorded on the calculated square on the territory of the Kamchatka Kura test site.
In December 1990, a modernized system took over on combat duty, which worked until June 1995. The complex was removed from combat duty as part of the signed START-1 agreement.
It was a backup communication system, which was used in case of impossibility to use the command system "Kazbek", as well as combat control systems of the Navy, Air Force and Strategic Missile Forces.
It is worth noting that there is no reliable information about the "Perimeter" system in open sources, but from indirect information it can be assumed that it was the most complex expert system, consisting of many sensors and communication systems. Apparently, the principle of its operation was as follows.
During combat duty, the system receives various data from the tracking systems. It includes both stationary and mobile control centers that ensure the operation of the main component of the Perimeter system - an autonomous control and command system - a complex software complex created on the basis of artificial intelligence, using many sensors and communication systems to control the situation.
In peacetime, all the main nodes are put on standby to monitor the situation and process the data coming from the measuring posts.
In the event of data transmission from early warning systems indicating a missile strike and the threat of an attack with the use of nuclear weapons, the Perimeter complex is put into combat mode, starting to monitor the operational situation.
The system monitors military frequencies, recording the presence and intensity of negotiations, monitors data from the early warning system, receives telemetry signals from the Strategic Missile Forces posts, and monitors the radiation level on the surface. In addition, point sources of powerful electromagnetic and ionizing radiation are tracked at specified coordinates, which coincide with seismic disturbances, which indicates multiple ground-based nuclear strikes.
Apparently, after processing all this data, the final decision is made on the need to deliver a retaliatory nuclear strike.
Another option for work is that after receiving data on a missile attack from an early warning system, the system is transferred to combat mode by the top officials of the state. If after that there is no signal to stop the combat algorithm, then the initialization of the retaliatory strike procedure begins. Thus, it is possible to completely exclude the possibility of a retaliatory nuclear strike in the event of a false alarm. In addition, even after the destruction of all persons with the authority to conduct launches, the possibility of a retaliatory strike remains.
If the fact of a massive nuclear strike is confirmed with the required reliability by sensory components, and the system has no connection with the main command centers of the Strategic Missile Forces, then the Perimeter can initiate a retaliatory nuclear strike even bypassing Kazbek, a system that many know by its most noticeable node - "nuclear suitcase" or subscriber complex "Cheget".
After the system receives an order from the Strategic Missile Forces, or after the command of the autonomous control and command complex, the launch of command missiles with a special warhead is initiated, which can transmit the launch codes to all carriers of strategic nuclear weapons on alert.
At all command posts of missile divisions and regiments, special RBU receivers of the Perimeter system are installed, which make it possible to receive signals from the warheads of command missiles. Stationary central command posts of the Air Force and the Navy were equipped with 15E646-10 equipment of the Perimeter system for the same purposes. After receiving the signals, they were transmitted further through special communication channels.
The receiving devices had hardware communication with the control and launch equipment to ensure the immediate execution of the launch order in a completely autonomous mode, even in the event of the destruction of all personnel.
According to unconfirmed reports, earlier in the Perimeter system there were command missiles created on the basis of the Pioneer MRBM. Such a mobile complex was named "Horn". The index of the complex itself is 15P656, and the missiles are 15Zh56. There is information about at least one division of the Strategic Missile Forces, which received the "Horn" complex for service. It was the 249th Missile Regiment, which was stationed in Polotsk.
And in December 1990, the regiment of the 8th missile division began to carry out combat duty, which received a modernized command missile system "Perimeter-RC", equipped with a command missile based on the RT-2PM "Topol" ICBM.
During combat duty, the complex periodically participated in command and staff exercises. The combat duty of the 15P011 command-missile system with the 15A11 missile (based on the MR UR-100) continued until June 1995, when the START-1 agreement was signed.
It is worth noting that the introduction of the 15E601 "Perimeter" system in 1983 did not go unnoticed by the United States, which always closely followed the missile test launches. On November 13, 1984, during the tests of the 15A11 command missile, American intelligence worked in a busy mode.
The 15A11 command missile was just an intermediate option, which was going to be used only in case of loss of communication between command posts and missile units based throughout the country. It was planned that the rocket will launch from the territory of the Kapustin Yar test site or from one of the mobile units, and fly over those parts of Ukraine, Belarus and Russia where the missile units are located, giving them launch commands.
But in 1984, the Americans did not have all the information about the Strategic Missile Forces command and control system. Some details appeared only in the early 1990s, when one of the developers of the system moved to the West.
On October 8, 1993, the New York Times published an article by columnist Bruce Blair entitled "The Russian Doomsday Machine", which revealed some details about the control system of the Soviet missile forces. It was then that the name of the Perimeter system appeared for the first time. It was then that the term “dead hand” appeared in English, referring to rocketry.
The system was designed to work in the face of the damaging factors of nuclear weapons. There was no reliable way to disable it.
According to Vladimir Yarynich, one of the developers of the system, published in Wired magazine, in peacetime, their system is "dormant", waiting for a signal to be activated in the event of a crisis. After that, the monitoring of the network of sensors - radiation, seismic and atmospheric pressure - is started to detect signs of nuclear explosions. Before initiating a retaliatory strike, the system checked four “ifs”. First, it was determined whether there had been a nuclear attack on Soviet territory.
Then the presence of communication with the General Staff was checked. If it was present, an automatic shutdown occurred, since it was assumed that officials with powers were still alive. But if there was no communication, then the Perimeter system immediately transferred the right to make a decision on launching to anyone who was in the command bunker, bypassing numerous instances.
As a rule, the officials of our country do not give any comments about the operation of this system. But in December 2011, Lieutenant General Sergei Karakaev, who is the commander of the Strategic Missile Forces, noted that the "Perimeter" still exists and is on alert.
According to him, if there is a need for a retaliatory missile strike, the Perimeter system will be able to transmit the necessary signals to the launchers. True, Karakaev stressed that at the moment the probability of a nuclear strike by one of the countries is negligible.
Note that in the West such a system was called immoral, but nevertheless it is one of the factors that can actually prevent a potential preemptive crushing nuclear strike.
