|Type||Intercontinental ballistic missile|
|Place of origin||Russia|
|Used by||Russian Strategic Missile Troops|
|Designer||Moscow Institute of Thermal Technology|
|Mass||36,000 kilograms (80,000 lb)|
|Warhead||4x each 150/300 Kt MIRV|
|Engine||Solid-fueled (last stage or warhead block can have liquid)|
|Propellant||solid, third or fourth stage (warhead block) can be liquid|
|5800 km demonstrated |
|Flight altitude||Several tens of km|
|Maximum speed||over Mach 20 (24,500 km/h; 15,220 mph; 6.806 km/s)|
|Inertial with GLONASS|
|Accuracy||90-250 m CEP|
The RS-26 Rubezh (in Russian: РС-26 Рубеж) (frontier or boundary, also known under the name of its R&D program Avangard Авангард) SS-X-31 or SS-X-29B (another version of SS-27), is a Russian solid-fueled intercontinental ballistic missile, equipped with a thermonuclear MIRV or MaRV payload. The missile is also intended to be capable of carrying the Avangard hypersonic glide vehicle. The RS-26 is based on RS-24 Yars, and constitutes a shorter version of the RS-24 with one fewer stages. The development process of the RS-26 has been largely comparable to that of the SS-20 Saber, a shortened derivative of the SS-16 Sinner. Deployment of the RS-26 is speculated to have a similar strategic impact as the SS-20.
After an initial failure in 2011, it was first test-launched successfully from the Plesetsk Cosmodrome on May 26, 2012, hitting its target at the Kura Range 5,800 km away minutes later. Further successful tests were performed from Kapustin Yar to Sary Shagan on October 24, 2012, and June 6, 2013.
According to the commander of the Russian Strategic Missile Forces, Colonel-General Sergei Karakayev, the RS-26 Rubezh could become operational as soon as 2016, however the missile remains in the developmental phase and has not yet achieved Initial operating capability. In 2018, it was reported that development of the RS-26 was frozen until at least 2027, and funding diverted toward continued development of the Avangard hypersonic glide vehicle.
The missile has been criticized by western defense observers for indirectly breaching the INF Treaty. The missile demonstrated, with a light or no payload, the ability to reach above the agreed 5500 km limit of the treaty. However all further testing have been flights with significantly shorter ranges. The RS-26 was twice tested at a distance of about 2000 km. While the RS-26 is technically an ICBM, its range falls just barely inside the ICBM category. According to a US magazine article, the RS-26 is exactly the same concept and a direct replacement for the RDS-10 Pioneer—known to NATO as the SS-20 Saber—which was banned under the INF treaty.
The RS-26 is designed to pose a strategic threat to European capitals and has the ability to target NATO forces in Western Europe. According to an article by Jeffrey Lewis entitled "The Problem With Russia's Missiles", the purpose of these weapons is to deter Western forces from coming to the aid of the NATO's newer eastern members that are located closer to Russia's borders.