The Dong Feng-2 (DF-2, or CSS-1 in its U.S. DoD designation) was China’s first indigenously-developed ballistic missile. It was a single-stage, liquid-propellant, short- to medium-range ballistic missile, capable of delivering a single nuclear warhead over a distance of 1,200 km.
Through the reverse-engineering of the Soviet R-2 missile (Project 1059), Chinese rocket engineers had gained considerable knowledge and experience in rocket design. As the next step towards an independent design, they proposed to increase the R-2 missile’s range to 1,000 km by increasing the rocket engine’s chamber pressure and carrying extra propellant. The military originally demanded an indigenous 2,000 km-range medium-range ballistic missile, but was persuaded by the Fifth Academy to scale down the objective to a more moderate 1,200-km range missile.
The design concept for the missile was proposed by the 1st Sub-Academy in March 1960, and approved by the leadership of the Fifth Academy in August of the same year. Designated Dong Feng-2 (DF-2), the missile was to inherit the guidance system and ground launch equipment of the R-2, but featured a range of modifications:
- Replacing the steel liquid oxygen tank with an aluminium alloy design to reduce the structural weight;
- Pressurised liquid oxygen tank to improve sealing performance;
- Redesigned chamber motor for better performance and reliability;
- Improved radio guidance system with increased power output;
- Blunt conical nose replacing the sharp conical design to reduce the re-entry heat;
- Simplified ground equipment for shorter launch preparation time.
The DF-2 programme entered engineering development in early 1961, with the target to conduct the first test launch before the National Day on 1 October of that year. However, the 5D60 liquid rocket engine did not pass the 125 s full-thrust test until November. More design flaws in the 5D60 engine were subsequently identified but the problems were ignored to avoid further delay in the first test launch.
The first DF-2 missile rolled out from the production line in February 1962 and was delivered to the Jiuquan missile centre (Base 20) in March. The test launch took place at 09:05:53 local time on 21 March. However, only several seconds into the flight, the missile began to veer off the course. The main engine was then on fire and shut down. The missile was soon in a free-fall and impacted the earth with a violent explosion at T plus 69 seconds.
The failure in the DF-2 test launch was a major setback in the Chinese strategic weapon programme. Chinese rocket engineers learned an expensive lesson in the importance of a systematic approach and strict quality assurance. The incident led to a complete overhaul of the missile development, with Li Shuang appointed Chief Designer responsible for overall project planning and decision-making on important technical matters. The Department of Systems Design was prompted as the leading organ for supporting the chief designer and coordination between all participants of the development – a model followed in all subsequent Chinese missile and space projects.
Between May 1962 and May 1964, the missile design team revisited all technical details of the DF-2 in order to identify design flaws. However, the issue with the missile’s structural strength remained unsolved. As a compromise, the military agreed to lower the missile’s technical and performance specifications temporarily. The engine’s thrust was lowered from 46 tonnes to 40.5 tonnes, and the maximum range was reduced from 1,200 km to 960 km.
On 29 June 1964, over two years after the first launch failure, a redesign DF-2 was successfully test launched from the Jiuquan missile centre. This was followed by two more successful test launches were conducted on 9 and 11 July. Between September and October 1964, five DF-2 test launches were conducted and the missile hit the target zone in each test, with a success rate of 100%.
Despite the success in the DF-2 development, the missile was still not fit for purpose for operational deployment. In August 1964, Chinese premier Zhou Enlai ordered the development of an improved variant of the DF-2 as the delivery system for China’s nuclear weapon. The improved variant, designated DF-2A, was included in China’s Missile Development Outline (1965-1972) drafted by the 1st Academy of the Seventh Ministry of Machinery Industry (Ministry of Astronautics).
Technical specifications for the DF-2A included:
- A maximum range of no less than 1,200 km;
- Engine thrust increased from 40.5 t to 45.5t;
- Specific impulse (Isp) increased from 219 s to 213.3 s;
- Full inertial guidance system replacing the original inertial + radio arrangement.
In order to ensure that the missile carried enough propellant to reach the maximum range, the DF-2 team designed an automated fuelling truck, which could keep pumping the rocket with the liquid oxygen propellant until the launch.
On 13 November 1965, the first DF-2A test launch was conducted successfully from the Jiuquan missile centre. This was followed by further 7 test launches in the following two months, with only one failure.
Missile-Delivered Nuclear Test
China successfully conducted its first nuclear test on 15 October 1964, with a nuclear (fission) device detonated atop a steel tower. Planning for a missile delivery system began over a year before, in March 1963. The Central Special Committee hosted a meeting on 12 June 1964 to discuss the missile-delivered nuclear test, and took the decision to use the DF-2A as the delivery system.
Development of the nuclear-armed DF-2A began in early 1965. The Central Special Committee agreed in March 1966 that the test would begin with a ‘cold test’ using a dummy warhead with no nuclear material, followed by a ‘hot test’ using a real nuclear warhead. The Seventh Ministry of Machinery Industry was asked to produce seven DF-2A missiles by August of the same year.
Between 10 April and 23 May 1966, the DF-2A made four flight tests to validate the reliability of the warhead detonation system. The launch team and test missiles arrived at the Jiuquan missile centre by September for the launch campaign. On 13 and 16 October, the DF-2A made two ‘cold’ tests carrying a dummy warhead. In both tests the warheads successfully detonated over the impact zone, proving the design of the detonation mechanism. The ‘hot’ test using the live nuclear warhead was then given go-ahead by the political leadership.
On 27 October 1966, a DF-2A carrying a 12 kT atomic warhead (code name: “548”) was launched from the Jiuquan missile centre at 09:00 local time. The rocket flew as planned and the warhead was then separated from the booster. At T plus 9 minutes and 14 seconds, the warhead was detonated at an altitude of 569 m above the ground inside the targeted impact zone at Lop Nor.
The DF-2 was similar in design and aerodynamic layout to the R-2/”1059” missile. It was a single-stage rocket powered by a 5D60 liquid engine burning a bi-propellant with alcohol as fuel and liquid oxygen (LOX) as oxidiser. The missile was 20.9 m in length and 1.65 m in diameter, with four delta-shape stabilising fins attached to the bottom. The rocket had a launch weight of 29.8 t. The maximum flight range was 960 km for the DF-2 and 1200 km for the DF-2A. The missile was transported on a truck-towed wheeled trailer, which also served as the launch platform during the missile launch.
Stages:....................1 Overall length (m):........20.90 Wingspan (m):..............N/A Core stage diameter (m):...1.65 Take-off mass (kg):........29,800 Take-off thrust (t):.......45.5 Thrust-weight ratio:.......1.53 Maximum range (km):........960 km (DF-2) 1,200 km (DF-2A) Payload:...................Single HE (DF-2) Single 12 kT nuclear (DF-2A) Propellant:................Liquid (LOX/Alcohol) Guidance:..................Inertial + radio (DF-2) Inertial (DF-2A)