DF-4 [the "Chingyu" missile]

The Dongfeng 4 missile is the first two-stage ballistic missile equipped by the Chinese Rocket Army. In the early days, the missile had a range of 4,000 kilometers. The main operational target was the US military base in Guam on the Pacific Ocean. The improved Dongfeng 4A missile has a range of 5000 kilometer, which covers most of Europe. It can be said that the Dongfeng 4 missile is China's first long-range ballistic missile with intercontinental operations.

Liquid ballistic missile weapon systems are huge and complex sophisticated weapon systems. It consists of missiles, ground equipment and facilities, and command and communication systems. The missile is composed of sub-systems that are closely related to each other, such as the warhead (nuclear and non-nuclear), body structure, power, control and guidance, telemetry and outer ballistics measurement. Each sub-system can be divided into many levels such as overall, whole machine, extension, components, components, contacts, wires, etc., and there are many links and interfaces; each sub-system generally has in-flight and ground monitoring equipment, and there are many Interfaces and coupling channels. The development of such a large and complex system is a huge system engineering, which must be carried out strictly in accordance with the development procedures.

In the early 1960s, China decided to develop intercontinental ballistic missiles. However, China ’s technical level at that time was not sufficient to directly develop intercontinental missiles. Therefore, between existing Dongfeng 1, Dongfeng 2 and Dongfeng 3 missiles and intercontinental missiles, a transition model was required.

The idea is to develop a two-stage test rocket as a transition based on medium-range missiles to solve the multi-stage rocket technology that intercontinental missiles must encounter, and this model can be used as a launch vehicle for launching satellites with slight modifications. In addition, in terms of development time, the equipment time of medium and long-range ballistic missiles is at least 2 years faster than that of intercontinental missiles.

In this way, in March 1965, China formally decided to develop the Dongfeng 4 medium and long-range ballistic missile. Eventually, on January 30, 1970, the first Dongfeng 4 missile was successfully tested and was formally installed in 1980.

Dongfeng IV is China's first two-stage liquid medium-range surface-to-surface missile. The first level is slightly modified based on Dongfeng No. 3; the second level is newly designed. The missile has a total length of 29m, a maximum diameter of 2.25m, and a takeoff mass of 82t. Both levels of propellant use red fuming nitric acid [RFNA] and unsymmetrical dimethylhydrazine [UDMH]. The ground thrust of the first-stage engine is 1120kN, and the vacuum thrust of the second-stage engine is 320kN. Mainly solve the engine high-altitude ignition and high-altitude performance test technology; inter-stage connection and high-altitude heat separation technology; attitude control technology after the slenderness ratio is increased.

Dongfeng 4 adopts strapdown-type fully compensated guidance scheme, which not only has lateral guidance, but also longitudinal guidance, and the method error is small. In order to improve the guidance accuracy, static pressure air floatation technology is adopted. The warhead is a thermonuclear warhead with a TNT equivalent of 3 million tons. The successful development of the Dongfeng 4 missile has played a very important role in strengthening China's strategic nuclear power, mastering multi-stage rocket technology, developing intercontinental missiles, launching artificial earth satellites, and developing space technology.

During the development of the Dongfeng 4 missile, Chinese researchers broke through a series of key technologies, including high temperature resistant materials, precise guidance systems, engine reliability, etc. Especially the Dongfeng 4 missile was designed as China's first two-stage liquid Medium and long-range ground-to-ground missiles, each stage is equipped with engines and fuel. This design can improve the rocket's continuous flight ability and final speed, which is also the advantage of multi-stage rockets.

However, the multi-stage rocket also needs to break through many technical difficulties, including the increase in the number of engines used, the complex structure, the slender structure, and the poor bending stiffness. It is not easy to achieve aerodynamic stability. The multi-stage rocket reduces reliability and increases costs due to these reasons.

The two-stage DF-4 (CSS-3) limited-range ICBM was designed initially to hit the US base at Guam and later modified to increase its range to 4750 kms so as to be able to strike Moscow. The launcher is a DF-3 with an added upper stage designed to provide power for boosting a 2,200 kilogram 3-MT warhead over a range of 5,500-6,000 kilometers. The first tests of this system were conducted from Jianshui [Chingyu] in November 1970 and 1971 to an impact area 2,050 nautical miles away. Continued testing and possible deployment were reported over the succeeding years.

The testing programs clearly indicated that China had the potential to deploy a missile capable of reaching European Russia, but only limited deployment occurred. In 1972 US intelligence estimated an IOC for this system as being expected in 1974 or 1975. Series production of the DF-1 and DF-2, along with development of the DF-5 might have stretched China's RDT&E capabilities to the limit, resulting in a low priority for deployment of what may have been a marginally effective missile.

Deployment actually began in 1975-76, but only four DF-4s were believed to be in place by 1984; and one report stated that these launchers were without warheads at the time. An estimated 30 DF-4s have been constructed for ballistic missile use. By 1995 between 10 to 16 were deployed, and by 1997 estimates of the deployed force ranged as high as 20 missiles.

China conducted a flight test of a DF-4 on 29 August 2002. The missile was monitored by U.S. intelligence as it was fired from the missile test facility in southern China to a remote impact area in the northwestern part of the country. As of mid-2002 China was believed to have about 20 DF-4s with a range of up to 4,340 miles.

Two launch configurations exist for the CSS-3: a rollout-to-launch site and an elevate-to-launch silo. Many of the DF-4s are stored in tunnels under high mountains, and are launched immediately outside the mouth of the tunnel. The missiles must be moved into the open and fueled prior to firing, an operational mode dubbed chu men fang pao (shooting a firecracker outside the front door), with the fueling operation apparently requiring about two hours.

In the early days, the Dongfeng 4 missile was equipped with a 3.2 Mt equivalent thermonuclear warhead weighing 2200 kg. Later, in 1986, China test-fired the Dongfeng 4 missile with a sub-guided multi-warhead capability. This improved type can carry multiple sub-guided nuclear warheads, each with an equivalent yield of about 50-100 Kt.

The civilian model of Dongfeng 4 missile is the famous Long March 1 carrier rocket. The rocket successfully launched China ’s first satellite Dongfanghong 1 in 1970. The successful launch of this satellite marked China ’s succession to the Soviet Union, After the United States, France, and Japan, the fifth country in the world to launch a domestic satellite with a homemade rocket.

US officials revealed that the PLA launched a Dongfeng-4 long-range ballistic missile at the Taiyuan Satellite Launch Center on the 24 August 2017. Relevant analysis pointed out that because this ballistic missile has a range of no more than 7000 kilometers, it is no longer the main force for the Chinese Rocket Army to test. At this time, it will be put out for test firing. According to The Diplomat Magazine, this test launch is so noteworthy because it has been in service for more than 40 years and is the oldest ballistic missile of the PLA; this test launch shows that the missile is not as old as the outside world thinks. It cannot be used, but proves that it can still be used as an important platform for the PLA to attack, especially in the face of India.