DF-31 (CSS-9)

The entry labelled CSS-9 should be handled carefully because modern open-source references most often associate the DF-31 family with CSS-10. The underlying system is still the same strategic category: a Chinese three-stage, solid-fueled intercontinental ballistic missile family deployed from road-mobile launchers. CSIS lists the DF-31 family as operational, with estimated ranges from roughly 7,000 to 11,700 km across variants. Its significance is mobility. Compared with older silo-based liquid systems, a road-mobile solid-fuel missile improves survivability and launch readiness for China's nuclear deterrent.

The DF-31 is a three-stage solid-propellant missile carried on a wheeled transporter erector launcher. CSIS describes the original missile as approximately 14-15 meters long with a 2-meter diameter and a single nuclear warhead; later DF-31A and DF-31AG variants extend range or improve off-road dispersal. From a database perspective, the technical story is the shift from a vulnerable, liquid-fueled strategic force toward a survivable mobile force. The TEL and canister launch architecture are therefore as important as the missile's range or payload values.

Open-source assessments place DF-31-family launchers in PLA Rocket Force units, with later variants expanding the number of survivable road-mobile ICBMs. NASIC's 2020 threat report separates CSS-10 Mod 1 and Mod 2 ICBMs and lists both as solid-fueled, road-mobile systems, with the Mod 2 category exceeding 11,000 km maximum range. That makes the family central to China's effort to maintain a credible second-strike option against continental-range targets while complicating adversary targeting of fixed launch infrastructure.