According to the Ministry of national defense, on the evening of June 19, 2022, China conducted a land-based midcourse anti missile interception technology test in China, which achieved the expected goal.
What is midcourse antimissile?
What are the advantages of midcourse antimissile?
Why do big countries attach great importance to the anti missile in the middle section?
By xiaodongfeng, liuxuanzun
This article comes from the global times client. The original article was first published on June 21, 2022. The original title was “three issues on the need for popular science in the middle of anti missile”.
Is midcourse antimissile equal to extraatmospheric antimissile?
The flight of ballistic missile is usually divided into initial stage, middle stage and final stage. As for the division of the initial, middle and final stages of ballistic missiles, a very popular saying is: the initial stage is the stage after the missile is launched until it flies out of the atmosphere; The middle segment is the stage of extraatmospheric flight; The last stage, also known as re-entry stage, is the flight phase of re-entry into the atmosphere. The so-called midcourse anti missile interception is usually to intercept ballistic missiles in the middle of flight. The midcourse antimissile system is the antimissile system for intercepting the midcourse antimissile.
However, zhangxuefeng, a Chinese military expert, said the statement was “not accurate enough”. At present, all countries generally define the 100 km high Carmen line as the dividing line of the atmosphere. Beyond 100 km is outer space and within 100 km is aerospace. For some short-range ballistic missiles, the apex of the missile has just left the atmosphere, or has not even left the atmosphere. For example, the height of the ballistic apex of the V2 ballistic missile, the ancestor of the ballistic missile, is only 80 to 90 kilometers. Different ballistic missiles have different ballistic apex heights. The short-range ballistic missile is less than 100 kilometers, while the intercontinental missile is more than 1000 kilometers. Therefore, it is obviously impossible to determine the different flight stages of a ballistic missile by a fixed altitude line or by its presence or absence from the atmosphere.
Zhangxuefeng said that the initial stage of the ballistic missile is also called the active stage, that is, the stage from the launch of the ballistic missile to the shutdown of the final stage engine, and the missile engine is in the working stage. The middle segment is the flight phase from the end of the initial segment to the final segment or re-entry segment. The re-entry phase is not calculated by entering the atmosphere within 100 km. Academically, the altitude at which the final engine is shut down is usually determined as the re-entry altitude. When the warhead falls below this height, it is considered as the reentry phase.
In addition, neither the middle segment anti missile system nor the end segment anti missile system is determined in strict accordance with the interception position. According to zhangxuefeng, the US “THAAD” system is actually transliterated according to the abbreviation of “terminal high altitude area defense system”. Its high limit of the kill zone is about 150 km to 200 km. In particular, its extended range type is not only beyond the atmosphere, but also in the middle of many medium – and short-range ballistic missiles, but it is still called the terminal anti missile system.
The most typical midcourse antimissile system often talked about now is usually developed for long-range and intercontinental ballistic missiles, mainly for interception outside the atmosphere. Some anti missile systems that intercept mid flight of medium range ballistic missiles are also classified as mid flight anti missile systems. However, the interception height of such an anti missile system is relatively low.
Why should big countries engage in mid course ABM
Theoretically, the ideal way to intercept ballistic missiles is to carry out multi-layer interception throughout the flight, try to move the first interception window forward, carry out the first interception in the boost phase, carry out the second interception in the middle phase, and “check the leaks and fill the gaps” in the final phase. However, the reality is that at present, the main interception mode for long-range ballistic missiles and intercontinental ballistic missiles is midcourse interception, which is related to the technical difficulties of interception at different stages.
According to zhangxuefeng, the ballistic missiles in the boost phase have poor mobility, and usually do not take penetration measures, so it is relatively easy to intercept them. However, the flight time in the boost phase is relatively short, which requires high response speed for early warning, tracking and interception. Moreover, the interception window is very small, and the acceleration ability of the interceptor is highly required. It is later than the missile launch, and it is difficult to “catch up”. Moreover, in the boost phase of interception, the own interception platform is close to the other side, and its own survival is also a problem. The overall cost is high and the technology is difficult. The main problem with the terminal interception is that once the interception fails, there are basically no remedial measures. Moreover, for intercontinental missiles and long-range missiles, they usually carry nuclear warheads. Even if they are successfully intercepted in the final stage, they may cause a large range of nuclear pollution in their own territory.
Therefore, mid course interception has become the main way for military powers to intercept medium – and long-range ballistic missiles and intercontinental missiles. The middle flight time of ballistic missile is long, which provides more windows for interception. Midcourse interception can also take advantage of the slower flight speed of the ballistic missile. Ballistic missiles reach their fastest speed at the end of the boost phase, and intercontinental missiles can reach about 22 times the speed of sound. Then the missile flies by virtue of inertia until it reaches the top of the trajectory. It is basically decelerating. After passing the top of the trajectory, it begins to fall and then starts to accelerate. The velocity of the ballistic missile warhead is the slowest at the ballistic apex. If the relatively slow velocity near the ballistic apex is used, the interception difficulty can be reduced.
Zhangxuefeng said that the infrared imaging guidance method is also very suitable for the mid course interception outside the atmosphere. At present, the midcourse interceptors in the United States usually use the direct collision kinetic energy interception technology. In order to achieve high hit accuracy, they often rely on infrared imaging guidance. The interceptor flies very fast. If it flies in the atmosphere, the infrared imaging seeker will be subject to the thermal noise caused by aerodynamic heating, which will seriously affect the target acquisition. There is no such concern outside the atmosphere, and the ambient temperature is very low, which is more suitable for infrared imaging seeker to capture targets.
Of course, the interception in the middle section is also difficult. For example, some US ballistic missiles will release some decoys in the middle of flight, and it is difficult to identify the decoys in this process.
What capabilities will be tested to build an anti missile shield
The most typical midcourse antimissile systems currently in service include
The US “ground-based midcourse defense system” (GMD) and the “Aegis” ballistic missile defense system equipped with “standard-3” interceptors.
The “land-based midcourse defense system” is not a weapon type, but a specific model. It is the first antimissile system in service in the world that uses conventional warheads to intercept intercontinental ballistic missiles. “Aegis” antimissile system can only intercept medium and long-range ballistic missiles at first. With the continuous upgrading and improvement of the “standard-3” interceptor, it also has the ability to intercept intercontinental ballistic missiles.
Russia’s A235 “nudolly River” antimissile system can also be regarded as a midcourse antimissile system. China has also successfully conducted many land-based midcourse antimissile tests. In addition, Israel’s arrow-3 and India’s PDV anti missile system have covered the middle section of some missiles.
There is a view that only the three major countries, China, the United States and Russia, have developed independently. Behind Israel is American funds and technical assistance, while India’s anti missile system even uses Israeli radar. In fact, the technical difficulty of anti missile is very high, and the investment is also very large. It is not the technology and funds of small countries that can independently support the interception at any stage.
From a technical point of view, the flight speed of ballistic missiles is very high. Intercepting such targets requires very high technical requirements for the interceptor itself. The development of the midcourse antimissile system is a systematic project, which requires a huge system. In addition to the interceptor itself, a large number of sensor networks are required. Among them, the early warning satellite is a basic configuration, which can quickly detect the launch of the opponent’s missile, roughly calculate the flight path, and then track and perform further accurate calculation by a large early warning radar.
In addition, shorter and more accurate radar should be used in the middle to accurately measure target parameters and identify targets. For example, the an/tpy-2 radar of the US “THAAD” system is usually deployed around the target country. Although its detection range is closer than that of P-band early warning radar, it has higher accuracy and provides parameters for accurate interception. The sea based X-band radar of the United States can also undertake this function. It is these sensor networks that form accurate information of incoming missiles and guide interceptors to intercept. These large radars are often worth hundreds of millions of dollars, which is not affordable to small countries.
According to the Russian satellite news agency reported on the 20th, the nuclear submarines “North devonsk” and “Smolensk” of the Russian Northern Fleet successfully completed missile live fire in the Barents Sea. The US Strategic Command confirmed on June 18 that the US Navy’s “Ohio” class strategic nuclear submarine successfully launched four Trident II D5 intercontinental ballistic missiles without real warheads in the waters near California.