Reports emerged in August 2015 that China was developing an intercontinental ballistic missile (ICBM) capable of striking any target in the world. The DF-5B is a liquid-fueled ICBM, an improved version of the DF-5A, with a superior engine and precision warheads.[1]

The DF-5 category is the only liquid-fueled ICBM in China’s nuclear arsenal.The Chinese Long March orbital carrier rockets are derived from DF-5 technology. To ensure better survivability of its missile forces, Beijing concentrated on solid-fueled missiles, which would provide these ballistic missiles with greater mobility. China is reported to have replaced its liquid-fueled DF-3s with solid-fueled DF-21 missile systems, although many analysts believe that a humble number of DF-3As with a range of 3,000 kilometers still exist in its arsenal.

However, what is intriguing is that as China proceeds towards developing survivable nuclear forces, shifting from the development of liquid-fueled ballistic missiles to solid fueled ones, what is the logic behind concentrating on the DF-5Bs? Being liquid fueled ballistic missiles, they have a high launch weight to throw weight ratio, enabling them to travel longer distances - they are reported to have a range extending up to 15,000 kilometers, giving them the longest range in China’s nuclear arsenal. This enables Beijing to easily keep targets in the US under threat.

The Russians are also developing liquid-fueled ICBMs, namely the Sarmat[2] which is reported to replace the SS-18 missiles.

The DF-5 category missiles are a silo-based missile system, and the DF-5Bs are also reported to be capable of carrying up to six warheads.[3] Since the 1980s, Beijing has worked on the possibility of MIRV-ing these missiles. However, due to technical failures in miniaturizinge nuclear warheads, this plan was not successful. Generally, multiple independently targetable re-entry vehicles (MIRVs) and other penetration aids to evade enemy defense systems could have an adverse impact on the range of the ballistic missile.

While China is developing hypersonic glide vehicles (HGVs) to negate this limitation on range, such technologies may be far from reality as credible capabilities at present. Liquid fueled missiles are heavier and, therefore, able to negate the range restrictions imposed by MIRVs. Moreover, liquid fueled propellants also enable the ICBMs to carry a greater number and more powerful warheads, along with more powerful counter-measures. The payload capacity of the DF-5 category is also heavy and, hence, can carry a greater number of lighter warheads. Their payload capacity is more than that of the DF-31 and the DF-41 category ICBMS given the need to enable the latter two ICBMs to be easily mobile even in rugged terrain.

The DF-5s are silo-based and hence, more susceptible to being destroyed by enemy attacks. However, this limitation has also been addressed, with Beijing. concentrating on dummy or fake silos to increase the survivability options of its silo based missile systems. These dummies make it difficult for adversaries to target the original silos. Moreover, the hardening of silos makes it further difficult to destroy such missile systems stored in these silos.

The development of hard and deeply buried tunnels where nuclear arsenals are stored could make it difficult to destroy missile capabilities stored inside the tunnels, even with bunker busting techniques.

Liquid-fueled missiles are hazardous to prepare and require a lengthy process for fueling and can be destroyed easily, giving rise to the “use them or lose them” dilemma which could question Beijing’s commitment to the "no-first use" nuclear doctrine.

Such developments on strengthening the survivability options of the DF-5s enable China to strengthen this doctrine, even with liquid fueled missiles. The preparation time for the DF-5As was less than the DF-5s, so the DF-5B could likewise have a preparation time less than the DF-5As.

China’s concentration on its solid propelled ICBMs, like the DF-41s and the DF-31s, as well as the DF-5As and Bs, enable it to move toward achieving a limited nuclear deterrent capability.

Debalina Ghoshal is a Research Associate with the Delhi Policy Group.