Imagine that on a calm morning, in a deep mountain bunker or the launch bay of an ocean-going submarine, several intercontinental ballistic missiles soared into the sky with huge fireballs. In a few minutes, they will accelerate to more than 20 times the speed of sound, rush out of the atmosphere, and enter the silent edge of space. And their final stop is the city at your feet.
After approaching the target, it will re-enter the atmosphere at a high speed of tens of Mach and land after about a minute. In the next few seconds, energy equivalent to hundreds of thousands of tons of TNT exploded on the building, wiping out the entire city in a matter of seconds.
At this time, your only hope is the extremely complex and sophisticated anti-missile system.
So, what exactly is an anti-missile system? Can it really protect you from an incoming missile? To successfully intercept a missile, three things need to be done: find the missile, lock onto the missile, and destroy the missile.
This is the first anti-missile system in human history, the Soviet Union's "System A".
Among them, this behemoth, which is 8 meters high and 150 meters long and looks like a dam, is its "eye" Danube-2 long-range radar warning station.
Its job is to find the location of the missile.
When a missile is discovered within a detection range of 1,200 kilometers, "Danube-2" will be the first to respond, mark the approximate orientation of the target within one kilometer, calculate the approximate height and initial speed of the missile, and then transmit these preliminary data to the command center.
Next, the three 4.65 m diameter radars take over.
After receiving data from the command center, they will lock the missile's position from three angles, accurate to within five meters.
Based on these data, it calculates the trajectory of the incoming missile and the best interception route, and sends instructions to the launch pad. Finally, the interceptor missile rushes toward the incoming missile along the preset trajectory according to the guidance of the guidance radar.
However, all of this was almost unimaginable in the 1960s - at that time, to build such a system, even the first step of "finding the missile" was almost impossible.
Although radar technology at the time was quite mature, it was primarily designed for aircraft.
Compared with aircraft, it is much more difficult to lock missiles. During World War II, the German dive bomber Stuka had a radar reflection cross-section of about 10 square meters. The reflective surface of the V-2 missile is only 0.1 square meters. This means that its echo on radar is only one percent as strong as that of an aircraft.
What's even more troublesome is that missiles are also much faster than aircraft, leaving a shorter window for radar to capture signals.
To find missiles, the detection capability required was dozens of times higher than the most advanced air defense radar at the time. Moreover, people's understanding of missiles at that time was also quite limited. Even for technicians who specialize in missiles, most of their knowledge is focused on how to launch and how to hit.
As for trajectory tracking, which is of greatest concern to anti-missile systems, research is almost blank. Even the reflective properties of missile warheads are not yet understood.
Therefore, even if the Central Committee of the Communist Party of the Soviet Union has decided to establish the project, there are still many academician-level experts who doubt the feasibility of the anti-missile system concept.
Even Korolev, the father of manned rockets who later launched Gagarin into space, publicly stated that technically speaking, there is no possibility of establishing an effective anti-missile system now or in the future.
In addition, the missile data itself is top secret. Missile experts are very cautious about relevant information and even refused to provide key data to the anti-missile research team.
Faced with this situation, the 30th Experimental Design Bureau, which is responsible for anti-missile system research, came up with a rather crude solution:Since you don’t know the missile’s trajectory, shoot more missiles and see what they look like on the radar.
Under the command of Chief Kisunik, the 30th Design Bureau built two experimental radar stations near a missile range in Kazakhstan: РЭ-1 and РЭ-2.
And for more than a year, the two radars were made to stare at the missile in the sky every day, and the recorded echo signals were compared with the telemetry information records of theodolite, camera and missile head rotation sensor, and the signal structure of the missile on the radar was analyzed bit by bit.
Through repeated observations and comparisons, Kisunik's team finally mapped out the complete radar signature of the missile. Finally in 1957 the РЭ-2 radar successfully tracked an R-2 missile in the air.
On the basis of these data, engineers further developed the "Danube-2" long-range radar warning station that can detect missile traces a thousand kilometers away.
At the same time, the "triangulation method" promoted by Kisuniko also successfully solved the radar performance problem.
The so-called triangulation is simply like three people pointing at the same missile in the sky from different directions - the intersection point of the three lines of sight in space is the location of the target.
When the target enters the precise measurement range, the three radars will be turned on at the same time to measure the precise coordinates of the missile in space. At this point, the anti-missile system research team finally clicked on all the necessary skill points and figured out the location of the missile.
Then, there is one last question left before building a complete anti-missile system: how to shoot down the missile.
The speed of a missile at the end of its flight usually reaches 3 to 4 kilometers per second. The speed of the interceptor missile itself is almost at this level.
At such a speed, the window period from the time the missile enters the precise detection range of the radar to the time it is launched and intercepted is only a few minutes. In these few minutes, the anti-missile system not only has to calculate the future intersection point of the two missiles, but also constantly corrects the flight trajectory of the interceptor so that it can accurately fly to that location.
It's like firing two bullets into the sky at the same time from hundreds of kilometers away, and then asking them to hit each other exactly in the air. You can imagine the difficulty.
Therefore, Soviet engineers did not spend their energy on improving missile accuracy, but chose a more "cost-effective" solution:Equip the interceptor with a special fragmentation warhead.
The warhead contains 16,000 24 mm diameter explosive balls coated with tungsten carbide. When the interceptor approaches the target, the warhead will detonate in the air and eject tens of thousands of high-speed metal fragments in the direction of the target, forming a huge fan-shaped kill zone of more than 70 meters.
It's equivalent to turning a great sniper into a troll. On March 4, 1961, the Soviet Union conducted the first true anti-missile interception test in human history.
In this experiment, a V-1000 interceptor missile equipped with a fragmentation warhead flew towards the predetermined interception point under the guidance of radar and computer, and finally successfully destroyed an R-12 missile at an altitude of 25 kilometers above the ground.
Even so, the Soviets still felt that it was not safe enough.
In the A-35 air defense system that was subsequently deployed in actual combat, it was simply replaced with a nuclear warhead. The super large AOE formed directly from the shock wave, radiation and high-energy particles of the nuclear explosion lifted up everything within a few kilometers. It truly achieves a certain sense of "killing mosquitoes with a cannon."
Don't ask if it's accurate, just say it's not possible. The Soviet high-level officials were very satisfied with this result, and soon put it into active service and put it on the Red Square military parade under the name of "high-speed anti-missile weapon".
Khrushchev also proudly declared in Pravda, "Our rocket can now hit a fly in space."
However, although Suizong personally stood up and won a great victory, as the first-generation anti-missile system in human history, the A-35 actually still has fatal problems.
First of all, in this system, the interceptor missile itself does not have independent computing capabilities. All trajectory calculations and guidance control rely on ground radars and command centers. Although nuclear bombs can ensure that they explode cleanly, the electromagnetic pulse generated during the explosion will not only interfere with enemy missiles, but also attack our own frequency band indiscriminately.
It is equivalent to a small "flood system". Once it explodes, everyone can only bayonet. In experiments, there have been situations where one's own radar and communication systems were knocked offline while anti-missile.
At this time, the defenders fighting on the local territory were blinded by their own nuclear bombs and their anti-missile systems could only hang up. However, the attackers thousands of kilometers away could fire another missile without being affected at all. Secondly, its interception altitude is only about 25 kilometers.
At this time, the warhead has entered the final dive stage with a speed exceeding Mach 20, and the interception system has only one chance. Once empty, the missile will land directly in a few seconds. The entire system has little room for error.
In order to solve these problems, modern anti-missile systems have undergone many modifications.
On the one hand, modern anti-missile systems no longer rely entirely on ground radar. Instead, they install part of the "eyes" and "brain" directly on the interceptor missile, allowing the missile to judge who to hit after flying near the target. The famous Patriot anti-missile missile is a typical example.
It has built-in radar and computing modules, and is equipped with jet devices for orbit change on the side. When the ground radar detects an incoming missile, it will first roughly point out the direction and trajectory of the target and send it nearby.
After that, the radar on the front end of the missile is activated to cooperate with the satellite to identify the target more accurately. Finally, the calculation module recalculates the trajectory and starts the jet device on the rocket to adjust the interception direction, and finally completes the interception.
Moreover, thanks to the accuracy of this system, the Patriots no longer need nuclear bombs, which have a self-damage of 800 AOE attacks, or even carry explosive warheads. They can smash incoming missiles by relying only on physical attacks.
On the other hand, people have also realized that instead of "fighting the operation" at the last moment, it is better to move the battlefield forward and turn their attention to the earlier mid-flight phase of the missile.
The middle section has the longest time, the smallest speed change, and the most stable flight path. Therefore, the anti-missile system can detect targets at a greater distance and has more time to calculate the interception window and launch interceptors. This leaves more time for anti-missile missiles and a greater error tolerance.
But the mid-stage anti-missile missile also has its own problems. At this stage, the missile flew too high and exited the almost airless atmosphere. For the terminal warhead that is tens of kilometers above the ground, under the influence of air resistance, the velocity curves of objects of different shapes and volumes are different.
Radar can accurately find warheads based on these characteristics.
But outside the atmosphere, due to the disappearance of air resistance, in the eyes of radar, the flight trajectory of a missile warhead is almost the same as that of a piece of metal. The number of anti-missile missiles on the defensive side is always limited. Generally speaking, to ensure a high interception rate, you must block at least one of three shots.
Under this battle damage ratio, even Hafk does not have that many rockets to shoot down all the missiles on the radar.
Therefore, in order to find real warheads in space, modern mid-course anti-missile systems, on the basis of radar detection, also integrate multi-band and multi-system detection methods such as infrared imaging and optical recognition.
Just "seeing clearly" is not enough. The mid-course anti-missile missile must also have the ability to maneuver flexibly in space.
At a distance of thousands of kilometers, even if the calculation error is only one thousandth, it may eventually deviate by dozens of kilometers. This requires that the interceptor missile itself must not only be able to "see" but also be able to "move" flexibly in space. And this depends on the core structure of the mid-course anti-missile missile, the exoatmospheric interceptor EKV.
When the main rocket sends the interceptor to the predetermined orbit, it will abandon all the boosters like a satellite launch, leaving only a small interceptor unit.
It consists of three parts: a propulsion system with a vector nozzle, a warhead responsible for destroying the warhead, and a probe for tracking the target. It's like a satellite flying very fast. The infrared detector and optical sensor located at the front end are responsible for confirming the target in the final stage.
Once the target is locked, the internal computing module will calculate the relative position and speed of the two in real time and predict the future intersection. Finally, the thruster carried by the EKV will quickly adjust the flight direction and "break" the trajectory of the interceptor to the correct position.
Today's anti-missile system no longer relies on a single interceptor or radar, but a defense network that combines multiple layers and methods.
Through the perception network constructed by low-orbit infrared early warning satellites, long-range phased array radars, etc., early detection can be achieved in the early stages of missile launch, providing sufficient time and data support for multi-stage interception.
At the end of the missile's flight, there is also a system that is more focused on high-altitude terminal interception as a backup. But even so, it cannot be 100% successful. The arms race between spear and shield continues to this day and may never be decided.
However, I still sincerely hope that there will be a day when human beings will no longer need it - even if it is only one in a billion.