The main purpose of the 15EX601 Perimeter system was the management of a retaliatory nuclear strike and guaranteed delivery of combat orders to individual command posts, launchers, strategic aircraft carrying combat duty, in case of impossibility to use the existing communication lines.
The system used a complex system of sensory sensors to measure seismic activity, air pressure and radiation. This should have made it possible to determine whether a nuclear strike had been inflicted in order to ensure the possibility of a nuclear retaliatory strike without using the “red button”. In the event of the disappearance of the connection with the OVC and the establishment of the fact of the attack, the procedure for launching rockets would be put into action, which allowed the USSR to strike back after its own destruction.
The autonomous command and control system being developed should have the ability to analyze changes in the global military and political environment in order to evaluate the teams that came in during a certain period of time. Based on this, it was concluded that something in the world went wrong. If the system believed that its time had come, then the procedure for launching missiles was initiated.
At the same time, active hostilities should not have started in peacetime, even in the absence of communication or withdrawal of the entire crew from BSP or KP posts. The system should have had additional parameters blocking its operation. Along with the above described extreme algorithm of operation, the system also had intermediate modes.
The development of a special command system was entrusted to Yuzhnoye Design Bureau. 30 August 1974, the government of the USSR signed the corresponding decree N695-227.
Later, the government set another task - to expand the range of functions that the command missile complex solved in order to bring combat orders to strategic missile boats, air force, naval and strategic missile command posts, naval and long-range missile aircraft aviation.
It was originally planned that the MR-UR100 (15A15) rocket will become the base, but later it was replaced with the MP-UR100 UTTH-rocket (15A16). After finalizing the management system, it was assigned the index 15А11.
In December, 1975 was presented the draft design of the rocket control. A special head unit with the index 15Б99 was installed on it, which included the original radio system developed by the OKB LPI. To ensure the necessary conditions of functioning, the head part needed a constant orientation in space.
For aiming the rocket in azimuth, a fully 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 setting the rocket on combat duty, store it during combat duty, even in the event of a nuclear effect on the launcher.
26 December 1979 of the year was the first successful launch of a command rocket with a transmitter equivalent installed. Testing was carried out on complex interfacing algorithms for all nodes of the system that took part in the launch, as well as checking the ability of the 15B99 head to adhere to a given flight trajectory - the top of the trajectory was at an altitude of about 4000 m with a 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 HSN 15B99. On the launchers of these missiles installed additional antennas and receivers. Subsequently, these improvements have affected all launchers and command posts of the Strategic Missile Forces.
Ground checks were carried out at the site of the Kharkov Physics and Technology Institute, the Novaya Zemlya nuclear test site and at the VNIIEF testing laboratories in the city of Arzamas. Here we tested 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 SU and SPS with nuclear effects exceeding the one specified in TTT MO was confirmed.
All work on the command rocket was completed by March 1982 of the year. And in January 1985, the complex took up combat duty. After that, command and staff exercises were periodically held in which the Perimeter 15-601 system participated.
In November 1984, the command rocket 15A11 was launched. After the 15B99 head part reached the passive part of the trajectory, a command was issued to launch the 15А14 rocket (Р-36М, PC-20А, SS-18 "Satan") from the NIIP-5 test site at Baikonur cosmodrome. The launch took place in the normal mode: after all the rocket stages had been worked out, it was recorded that the target was hit on the target square on the territory of the Kamchatka Kura test site.
In December, the upgraded system, which operated until June of the 1990 year, took over combat duty on 1995 of the year. The complex was removed from combat duty in the framework 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 according to indirect information it can be assumed that it was the most complicated expert system, consisting of many sensors and communication systems. Apparently, the principle of its action was as follows.
During combat duty, the system receives various data from the tracking systems. Its structure includes both stationary and mobile control centers that provide the main component of the Perimeter system - an autonomous command and control system - a complex software complex created on the basis of artificial intelligence, using a variety of sensors and communication systems to monitor the situation.
In peacetime, all the major nodes are transferred to standby mode to monitor the situation and processing data from measuring posts.
In the case of data transmission from early warning systems indicating a missile strike and the threat of an attack using nuclear weapons, the complex "Perimeter" is transferred to the combat mode, starting to monitor the operational situation.
The system monitors the military frequencies, recording the presence and intensity of negotiations, monitors the data from the EWS, receives telemetry signals from the Strategic Missile Forces, controls the radiation level on the surface. In addition, point sources of powerful electromagnetic and ionizing radiation are tracked along given coordinates, coinciding with seismic disturbances, which indicates multiple ground-based nuclear strikes.
Apparently, after processing all these data, a final decision is made on the need to strike a nuclear strike.
Another option of work is that after receiving data on a missile attack from an early warning system, the system is transferred to combat mode by the first persons of the state. If after this there is no signal about stopping the combat algorithm, then the response strike will be initialized. Thus, it is possible to completely exclude the possibility of a nuclear strike in the event of a false positive. In addition, even after the destruction of all persons with authority to conduct launches, the possibility of retaliation remains.
In the event that the fact of a massive nuclear strike is confirmed with the required accuracy of the sensory components, and the system has no connection with the main command centers of the Strategic Missile Forces, the Perimeter can initiate a retaliatory nuclear strike even bypassing Kazbek, a system that many people know by its most noticeable the node - the “nuclear suitcase” or the subscriber complex “Cheget”.
After the system receives an order from the OVC of the Strategic Missile Forces, or after a command from an autonomous command and control complex, command missiles are launched with a special warhead that can transmit the launch codes to all strategic nuclear weapons carriers on alert.
At all command posts of missile divisions and regiments, special receivers of the RBU of the Perimeter system have been installed, which allow receiving signals from the warheads of command missiles. The stationary central command posts of the Air Force, Navy were equipped with the X-NUMX-15-646-equipment of the Perimeter system for the same purposes. After receiving the signals, they were transmitted further through special communication channels.
The receivers had hardware communication with the control and starting equipment to ensure the immediate execution of the order to launch in a completely autonomous mode, even in the case of the destruction of all personnel.
According to unconfirmed reports, previously, as part of the Perimeter system, there were command missiles created on the basis of the Pioneer MRBM. Such a mobile complex received the name "Horn". The index of the complex itself is 15P656, and the rocket is 15Ж56. There is evidence of at least one unit of the Strategic Missile Forces, which received a set of "Horn" in service. It was the 249 th missile regiment, which was stationed in Polotsk.
And in December, the 1990 th rocket division regiment began combat duty, which received the upgraded Perimeter RC command and control missile system, equipped with a command missile based on the Topol IC-RTB 8PM.
During combat duty, the complex periodically participated in command and staff exercises. The combat duty of the command and missile system 15P011 with the 15А11 rocket (based on MR УР-100) continued until June of 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, who always closely followed the test rocket launches. 13 November 1984 of the year, during the tests of the command missile 15А11, American intelligence was working hard.
The command missile 15А11 was just an intermediate option that they were going to use only in case of loss of communication between command posts and missile units based throughout the country. It was planned that the rocket would launch from the territory of the Kapustin Yar test site or from one of the mobile installations, 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 control system. Some details appeared only in the beginning of 1990-s, when one of the system developers moved to the West.
October 8 The 1993 of the Year in the New York Times published an article by Bruce Blair’s columnist entitled “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 was lit for the first time. It was then that the notion of dead hand appeared in English - “dead hand”, referring to rocket technology.
The system was designed to work in the conditions 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, their system is “dozing” in peacetime, waiting for a signal to be activated in the event of a crisis. After that, monitoring of the network of sensors — radiation, seismic and atmospheric pressure — is launched to detect signs of nuclear explosions. Before initiating retaliation, the system checked four “ifs”. First, it was determined whether there was a nuclear attack on Soviet territory.
Then, the connection with the General Staff was checked. In the case of its presence, an automatic shutdown occurred, as it was assumed that the officials with authority were still alive. But if there was no connection, the Perimeter system immediately transferred the right to make a decision on launch to anyone who was in the command bunker, bypassing numerous instances.
As a rule, officials of our country do not give any comments on the work of this system. But in December, 2011, Lieutenant-General Sergey Karakaev, who is the commander of the Strategic Missile Forces, noted that the "Perimeter" still exists and is on combat duty.
According to him, if the need arises for a reciprocal missile strike, the Perimeter system will be able to transmit the necessary signals to the launchers. However, Karakaev stressed that at the moment the probability of the use of a nuclear strike by one of the countries is negligible.
Note that in the West, such a system was called immoral, but still it is one of the factors that can actually prevent a potential preventive crushing nuclear strike.