DF-31AG Test and PLA Rocket Forces’ Nuclear Choices

Summary

The testing of DF-31AG ICBM shows both the success and vulnerabilities in China’s nuclear choices. The mixed deployment of both liquid-fuelled and solid-fuelled ballistic missiles for nuclear deterrence indicates that the objective to move fully into solid-based mobile ballistic missiles is yet to be achieved.

The intensification of the US–China great power competition is fuelling China’s efforts to strengthen its nuclear deterrence and signalling. Though China’s nuclear forces modernisation is opaque with regard to the number of warheads or delivery vehicles, the sophistication in the testing of ballistic missiles in recent years shows that it is seeking to make its retaliatory capability against the US more credible. On 25 September 2024, China’s PLA Rocket Forces (hereby Rocket Forces) conducted a DF-31AGⁱ (solid-fuelled) inter-continental ballistic missile (ICBM) test. This test was significant since it was a full-range flight test (全程试验) that China did after a gap of 44 years. China’s first ever full-range ICBM test was that of the DF-5, which was tested in 1980. In such a case, what does the DF-31AG test tell us about China’s nuclear choices in a heightened nuclear environment when facing US nuclear superiority?

Analysts have indicated that the Rocket Forces tested the ‘operational validation’ and ‘ISR capabilities’ of the DF-31AG missile.ⁱⁱ The timing of the test also led analysts to speculate that the Rocket Forces conducted the test to prove the reliability of their nuclear deterrence. The questions about the competency had risen when the Rocket Forces removed several high-ranking officials from the organisation for graft. In the last decade, CPC Chairman Xi Jinping had considerably expanded the importance of the Rocket Forces when he elevated the organisation from a branch to an independent service in 2015 and also appointed Wei Fenghe, a former commander as the Defence Minister of China in 2018. But in 2024, the CPC expelled Wei Fenghe over corruption.

Some analysts also argue that the test was a response to the US deployment of MRBMs in its neighbourhood after the US opted out of INF (Intermediate-Range Nuclear Forces) treaty in 2019. Philippines was the first country to deploy the US Typhoon missile system in 2024.ⁱⁱⁱ If the US had been still part of the INF Treaty, the deployment of mid-range missiles would have violated the terms and conditions of the treaty, which prohibits the development and deployment of ground-based mid-range ballistic and cruise missiles.

DF-31 AG Test: Key Characteristics

The PLA Rocket Forces carried out the DF-31AG ballistic missile test with a dummy warhead towards the high seas of the Pacific Ocean. The Ministry of Defence stated that China informed the “relevant countries” in advance and that the test was intended to assess the performance of the weapons and training level of the troops.^iv According to Chinese officials, the missile landed accurately in a pre-determined area, and achieved the intended target and purpose.^v The DF-31AG ballistic missile, like the DF-41 (solid-fuelled) ICBM, uses a cold launch method and is equipped with rubber tube launch technology.^vi China conducts most of its ballistic missile tests, including ICBMs, from its missile testing ranges in the deserts through a high-trajectory test (高弹道).

In this case, the Rocket Forces opted out of a high-trajectory test and instead did a full-range test leading it to select the impact area of the missile in the Pacific waters. The test data would have been useful in verifying the performance of the ballistic missile from launch to the re-entry phase, trajectory and guidance control, stability and navigation performance as well as accuracy of the missile. The Rocket Forces are claiming that the test demonstrated that they have mastered the missile guidance, navigation and control systems of the ballistic missile and could accurately control the impact point.

The DF-31AG uses the Beidou navigation satellites making the tracking and control of the ballistic missile fully autonomous, and uses inertial guidance system that makes the missile more accurate.^vii Since the military reforms in 2015, the PLA has been pushing towards conducting military training resembling ‘actual combat conditions’ and a full-range flight test rather than a high-trajectory test that satisfies these conditions too.^viii The DF-31AG test completed its 12,000 kms flight in 20 minutes. The DF-31AG (an upgraded version of the DF-31A ballistic missile) has a high-mobility launch capability and can conduct operations without launch support, unlike the DF-31A ballistic missile, which needs to have launch support operations such as pre-determined area and temporary concrete structures to withstand the launch of the missile.^ix

The 1980 DF-5 Test: Key Characteristics

First, the PLA required three years to conduct the 1980 DF-5 ICBM test. It required a vast support system and a task force made up of over 5,000 personnel.^x The DF-5 ICBM test was conducted with the leadership organising the ‘580’ mission (580任务), where the PLA Navy task force (18 ships and four helicopters) measured landing points and conducted oceanographic surveys to collect data of the missile test.^xi

Second, the then Second Artillery conducted the first test to fill the deterrence gaps in their nuclear capabilities. General Zhang Aiping,^xii who had supervised the Two Bomb and One Satellite (两弹一星)^xiii programme, also set up the “three gaps” (三抓) tasks^xiv in 1977. Gen Zhang Aiping initiated the “three gaps” (三抓) tasks with regard to nuclear deterrence—the development and testing of ICBMs, SLBMs and communication satellites by the early 1980s. The SLBM test was conducted in 1982 and the communication satellite was launched in 1984. The ICBM test was considered as the most important among the ‘three gaps’ initiative and therefore given immediate priority and required organisational mobilisation, construction of survey ships, selection of landing area, etc.

The ‘three gaps’ project happened after the biggest political turmoil in the CPC history, the Cultural Revolution, which disrupted defence programmes. In 1965, Qian Xuesen^xv had proposed the ‘Eight Year Four Missile’ plan, where China was supposed to conduct the tests of DF-2 (IRBM/ICBM), DF-3 (intermediate range), DF-4 (intermediate to long-range) and DF-5 (ICBM) by 1972.^xvi However, the Cultural Revolution disrupted the plan and when Zhang Aiping took over the reins of PLA’s National Defence Science and Technology Commission in 1975 after his purge (he was imprisoned for six years), his ‘three gaps’ was designed to bring working order to the disrupted programmes. The DF-5 test, therefore, was a product of the success of the reorganisation and coordination of the missile and defence programmes.

Third, the 1980 ICBM test was a surprise test, unlike in September 2024 when China informed other countries in advance, which indicated a certain level of confidence about the outcome of the test as well as risking of missile test data leaks (presence of ships and radar stations of other countries during the flight path).

Rocket Forces’ Deployment

The DF-31AG test is to signal China’s nuclear deterrence capabilities to its adversaries, which shows to some extent the success of the streamlining of the priorities of the Rocket Forces. China has been developing its nuclear missile capability to deter the US from using its nuclear superiority to issue a nuclear threat during a potential conflict involving its core interests. The decision to test the DF-31AG in Pacific waters and exposing it to surveillance from its adversaries meant that China was keen on nuclear signalling.

The Rocket Forces are conveying that they are able to calculate real combat trajectories, missile guidance and hit accuracy, and the reliability of the missile through use of its naval, radar and satellite assets. It is intended to assure that their retaliatory strike is effective and that the Rocket Forces have reached technical maturity. If the Rocket Forces are attempting to convey their deterrence capability through the testing of DF-31AG, then what are the characteristics of their deterrence challenges?

A cursory look at China’s ICBM development would reveal that it has always been a long-drawn process, where the Rocket Forces could only develop solid-fuelled ICBMs in the 1990s. The 1965 ‘Eight Year Four Missile’ plan was to culminate in the development of solid-fuelled ballistic missiles. Although China achieved the long-range capability for delivering its nuclear weapons, the survival of its missiles became a priority. Hence, Gen Zhang envisioned to transform China’s nuclear capabilities from liquid-fuelled to solid-fuelled missiles, develop land-based and sea-based deterrence and move from silo-based towards mobile launch missiles.^xvii

However, instead of completely replacing its liquid-fuelled ICBMs with solid-fuelled ballistic missiles, the Rocket Forces are upgrading more liquid-fuelled ICBMs such as the DF-5B and building more hardened silos.^xviii China has been testing upgraded liquid-fuelled ICBMs such as DF-5B and constructing multiple ICBM silos to create uncertainty in the minds of the adversary about the number and location of its liquid-fuelled ICBMs. The silos are hardened to withstand damage from conventional firepower. Adversaries would have to hit all of their silos to make sure that all the liquid-fuelled ballistic missiles are destroyed. Moreover, the newer missiles are also being developed in a nuclear environment where the Chinese perceive that many major powers including the US are modernising their nuclear forces.^xix

The DF-41, which remains one of their few solid-fuelled ICBMs that can pose a credible threat to its adversaries, had initial deployment only in 2020. The DF-5B ICBM, though upgraded and difficult to destroy through conventional means, can be detected. Given that the DF-31AG ICBM has passed the verification of the full-range test, it can be expected to replace the ageing DF-31 missile series.

The testing of DF-31AG, therefore, shows both success and vulnerabilities in China’s nuclear choices. The mixed deployment of both liquid-fuelled and solid-fuelled ballistic missiles for their nuclear deterrence indicates that the objective to move fully into solid-based mobile ballistic missiles has yet to be achieved. Even the testing of newer missiles such as the DF-5B (liquid-fuelled) ICBM attests to this strategy.

Conclusion

The DF-31AG does not need launch support, which means it does not have to rely on launch sites for support, or kept hidden underground to avoid detection or attack, which can ensure its survivability. The DF-31AG can also be used in counter-attack rapidly because it integrates transport, erector and launch (TEL) facilities for launch. Prior preparation such as hardened ground, duration of response such as the time needed to construct launch sites are not needed, and therefore is largely secure from US surveillance and reconnaissance.

The Rocket Forces were perhaps under pressure to signal the effectiveness of their nuclear deterrence against adversaries in a heightened nuclear environment unrestrained by both the unravelling of the ABM (Anti-Ballistic Missile) treaty and the INF treaty and modernisation of nuclear forces by other major powers. Simultaneously, the Rocket Forces continue to rely on liquid-fuelled ICBMs for nuclear deterrence. The DF-31AG is emerging as the ICBM of choice of their solid-fuelled capability.

Like the first test of DF-5, the DF-31AG represents the attempts of the Rocket Forces to streamline its organisational resources in a more efficient manner to counter vulnerabilities in its deterrence capabilities. The DF-31AG test might also be seen as an attempt to prove that the corruption scandals in the Rocket Forces have not affected their capabilities or to counter the notion that their missile dominance in its neighbourhood has weakened due to the US deployment of its MRBM systems. The DF-31 AG test is proof that China is continuously upgrading its deterrence capabilities while achieving its long-term goals of increasing the effectiveness of its retaliatory capabilities through solid-fuelled missiles.

Keywords : Ballistic Missile, China, People's Liberation Army (PLA)