Missile RS-26 Rubezh (SS-X-31)

The RS-26 Rubezh, designated by NATO as SS-X-31, is a Russian solid-fueled ballistic missile developed as a shortened derivative of the RS-24 Yars utilizing one fewer stage. Following an initial launch failure in September 2011, the missile completed its first successful test flight in May 2012 from the Plesetsk Cosmodrome to the Kura Missile Test Range. Additional test firings took place between Kapustin Yar and Sary Shagan in 2012 and 2013. In 2018, procurement under the state armament plan until 2027 was frozen, with funding diverted toward the Avangard hypersonic glide vehicle.

The RS-26 is equipped with a thermonuclear multiple independently targetable reentry vehicle (MIRV) or maneuverable reentry vehicle (MaRV) payload, and is intended to carry the Avangard hypersonic glide vehicle. Based on payload weight, the missile functions as either an intermediate-range or intercontinental ballistic missile. Flight testing demonstrated that carrying a lighter payload allowed the missile to reach intercontinental distances, whereas flights with standard payloads fell within intermediate-range boundaries.

Operated by Russia, the system attracted international criticism for its testing profile, which observers asserted was designed to circumvent the limits of the Intermediate-Range Nuclear Forces (INF) Treaty prior to the treaty's dissolution. On 21 November 2024, Ukrainian military sources reported that Russian forces launched conventionally armed RS-26 missiles against infrastructure in Dnipro. Russian official statements later clarified that the strike was conducted not by the RS-26, but by a new intermediate-range ballistic missile model named Oreshnik fitted with a non-nuclear hypersonic payload.