RT-2
The RT-2 (8K98), NATO-designated SS-13 Savage, was a Soviet three-stage, solid-propellant intercontinental ballistic missile developed as the first such system in the USSR's strategic arsenal.[1] Flight development testing occurred from December 1969 to January 1972, culminating in initial deployment on 28 December 1972.[1] Designed for silo launching, it featured sequentially arranged solid-fuel stages and an inertial guidance system, enabling delivery of a single reentry vehicle weighing approximately 1,200 pounds to a maximum operational range of 5,500 nautical miles (about 10,200 km).[1][2] Development of the RT-2 began in 1961 at the OKB-1 design bureau, succeeding the earlier RT-1 series and representing a shift toward reliable solid propulsion amid the Cold War arms race.[3][2] The missile's introduction marked a technical milestone for Soviet rocketry, though its deployment was limited compared to liquid-fueled predecessors like the R-36, partly due to ongoing refinements in solid-fuel reliability and accuracy.[2] A modernized variant, the RT-2P, incorporated improved controls and increased payload capacity, extending range by 400 km and enhancing operational flexibility.[2] The RT-2 underscored early challenges in scaling solid-propellant technology for ICBMs, influencing subsequent systems like the RT-2PM Topol, while its single-warhead configuration reflected doctrinal priorities for assured retaliation over multiple independently targetable reentry vehicles in the early 1970s.[1][3]Development
Origins and Early Design
The RT-2, designated 8K98 by the GRAU index and known to NATO as SS-13 Savage, emerged from the Soviet Union's strategic imperative in the early 1960s to field a reliable solid-propellant intercontinental ballistic missile (ICBM) amid escalating nuclear arms competition with the United States. Development was initiated by Design Bureau OKB-1 under Chief Designer Sergei Korolev, leveraging experience from the solid-fueled RT-1 intermediate-range ballistic missile, with work commencing between 1961 and 1963.[3][4] The project represented the USSR's first dedicated effort to produce a domestically engineered solid-fuel ICBM, transitioning from liquid-propellant systems vulnerable to longer preparation times.[1] Preliminary design work on the RT-2 concluded in 1963, outlining a three-stage configuration with sequentially fired solid-propellant motors linked by structural trusses for enhanced stability and transportability.[1] Early engineering emphasized silo-based deployment to ensure survivability, with inertial guidance for precision targeting and a single reentry vehicle housing a nuclear warhead of approximately 600-750 kilotons yield.[2] The design incorporated composite materials and simplified staging to reduce launch complexity compared to prior liquid-fueled ICBMs like the R-16, aiming for rapid readiness and resistance to preemptive strikes.[5] Following Korolev's death in 1966, his successor Vasily Mishin oversaw refinements to the initial blueprint, integrating advancements in propellant chemistry and motor casing derived from RT-1 testing.[3] This phase prioritized scalability for intercontinental range—exceeding 9,000 kilometers—while maintaining a relatively compact footprint suitable for hardened silos, reflecting causal priorities of deterrence through assured retaliation.[2] Approximately 60 missiles were eventually produced by 1972, underscoring the design's feasibility despite challenges in solid-fuel reliability during the era.[6]Key Technological Innovations
The RT-2 (NATO: SS-13 Savage) introduced solid-propellant technology as the Soviet Union's first intercontinental ballistic missile (ICBM) to employ this fuel type, departing from the liquid propellants dominant in prior designs like the R-16 and UR-100.[1][3] This shift enabled indefinite missile storage without pre-launch fueling, reducing preparation time from hours to minutes and enhancing survivability against preemptive strikes by eliminating visible fueling signatures.[2] Solid propellants also improved operational reliability, as they avoided the corrosion and volatility issues of hypergolic liquids, while providing consistent thrust without complex ignition sequences.[3] The missile's three-stage architecture, with sequentially firing solid-rocket motors, optimized range and payload delivery, achieving a maximum operational reach of approximately 10,000 km with a 750-kiloton warhead.[1] Each stage integrated lightweight composite casings and high-energy propellants derived from the RT-1 intermediate-range missile's technology, scaled for ICBM demands, which minimized structural mass and boosted specific impulse efficiency.[3][4] Inertial guidance formed the core of the RT-2's navigation, relying on onboard gyroscopes and accelerometers for autonomous trajectory correction without external inputs, a refinement over earlier Soviet systems that reduced vulnerability to electronic countermeasures.[2] This system, developed under Sergei Korolev's OKB-1, incorporated early digital computing elements for real-time error compensation, achieving a circular error probable (CEP) suitable for counterforce targeting despite the era's limitations.[3] These features collectively advanced Soviet strategic deterrence by prioritizing rapid response and silo-based readiness.[7]Testing and Deployment
Flight Test Program
The flight test program for the RT-2 (8K98) intercontinental ballistic missile, the Soviet Union's first operational solid-propellant ICBM, began on February 5, 1966, at the Kapustin Yar test range, marking the initial evaluation of its three-stage solid-fuel design derived from earlier Kosmos booster technology.[2] The program proceeded in two primary phases: an initial development phase focused on single-missile launches to validate propulsion, guidance, and reentry capabilities, followed by state acceptance trials incorporating salvo firings.[1] In the first phase, conducted from February through July 1966 exclusively at Kapustin Yar, seven successful launches demonstrated the missile's basic flight performance over ranges up to 10,000 kilometers, targeting impact zones in the Kamchatka Peninsula.[1] These tests addressed early challenges in solid-propellant reliability and silo compatibility, building on prior liquid-fuel ICBM experience but adapting to the RT-2's non-cryogenic advantages for rapid launch preparation.[2] The second phase shifted to the Plesetsk Cosmodrome from October 1966 through November 1968, utilizing hardened silos to simulate operational conditions in northern latitudes, with 25 launches completed—21 individual and four in two-missile salvos—to assess accuracy, payload separation, and environmental resilience.[1] All 25 Plesetsk firings succeeded, contributing to the missile's formal acceptance into service on December 18, 1968.[8] Overall, the RT-2 underwent 44 development flights and 19 operational test launches through 1974, including five from production silos at Yoshkar-Ola to verify field deployment procedures.[3] These efforts confirmed a maximum range exceeding 10,000 kilometers with a single 1-megaton warhead, though later variants like the RT-2P extended testing into 1972 for improved inertial guidance and MIRV potential.[1] The program's success rate underscored the feasibility of solid-fuel ICBMs for strategic deterrence, despite initial delays from propellant formulation issues resolved through iterative ground testing.[4]Initial Operational Capability
The RT-2 (8K98), designated SS-13 Savage by NATO, achieved initial operational capability in 1969, with deployment commencing on 18 December 1968 at silo launchers near the Plesetsk Cosmodrome in northern Russia.[1][2] This marked the Soviet Union's first deployment of a solid-propellant intercontinental ballistic missile, transitioning from liquid-fueled systems like the RT-1 and RT-2 variants that required extensive fueling procedures prior to launch.[2] The system's early rollout involved equipping the 50th Missile Army under the Strategic Rocket Forces, with initial silos configured for rapid response amid the ongoing Cold War arms competition.[9] By 1971, the RT-2 reached its maximum deployment of approximately 60 missiles, concentrated in converted pads originally designed for earlier liquid-fuel ICBMs such as the R-36.[3] These deployments enhanced Soviet second-strike capabilities due to the solid fuel's reduced preparation time, estimated at under 30 minutes from alert to launch, though reliability concerns limited the program's expansion beyond this scale.[1] Western intelligence assessments at the time noted the RT-2's role in countering U.S. Minuteman deployments, but its single-warhead configuration and vulnerability to silo-based countermeasures prompted subsequent upgrades toward MIRV-capable successors.[3] Early operational units underwent rigorous training and validation flights from Plesetsk, confirming the missile's range of up to 10,000 kilometers with a 750-kiloton warhead, though actual combat readiness was constrained by ongoing teething issues in solid-propellant storage and guidance integration.[2] The RT-2's IOC thus represented a doctrinal shift toward survivable, storable strategic forces, influencing later systems like the RT-2PM Topol, despite its relatively short service life ending in the mid-1970s.[1]Technical Design
Propulsion System
The RT-2 intercontinental ballistic missile utilized a three-stage solid-propellant propulsion system, representing the Soviet Union's inaugural deployment of such technology in an ICBM.[3] This configuration consisted of sequentially arranged sustainer stages powered by solid-fuel motors, interconnected via trellised trusses to facilitate structural integrity during ascent.[1] [2] Aerodynamic stability was maintained by four trellised fins, which deployed post-launch to counteract flight perturbations without relying on liquid-propellant gimbaling.[1] Solid propellants eliminated the need for pre-launch fueling, enabling rapid silo-based readiness and reducing vulnerability to preemptive strikes compared to contemporaneous liquid-fueled systems like the R-36.[8] The design prioritized storability and environmental stability within hardened silos, where the propellant grains remained viable for extended periods under controlled conditions.[10] Development of these motors stemmed from earlier efforts on the RT-1 intermediate-range missile, scaling solid-fuel technology to achieve intercontinental ranges exceeding 9,000 km with a single warhead.[4] [3] Specific thrust profiles and propellant compositions for the RT-2 stages remain classified, though the system's overall launch mass of approximately 45,100 kg supported efficient boost phases tailored for silo ejection and vacuum-optimized upper-stage burns.[6] This propulsion architecture contributed to the missile's operational deployment from 1968, with roughly 60 units produced by 1972 before phase-out in favor of more advanced solid-fuel designs. The inherent simplicity of solid motors—lacking turbopumps or cryogenic handling—enhanced reliability, though early Soviet solid propellants exhibited lower specific impulse than later composites, constraining payload fractions relative to Western counterparts like the Minuteman III.[3]Guidance and Warhead Configuration
The RT-2 intercontinental ballistic missile utilized an inertial guidance system based on a gyro-stabilized platform incorporating floating gyroscopes and pendulous accelerometers for attitude control and trajectory correction.[1][2] This configuration enabled autonomous navigation without external updates, relying on pre-launch alignment and onboard sensors to achieve the required accuracy for targets up to 9,000–10,000 km distant, though circular error probable (CEP) values were estimated at around 1–2 km based on Soviet solid-fuel ICBM performance of the era.[1] The system's design prioritized reliability in silo-based launches, compensating for the limitations of early solid-propellant integration by avoiding complex radio or stellar augmentation seen in contemporaneous liquid-fueled missiles.[2] In terms of warhead configuration, the RT-2 carried a single reentry vehicle (RV) housing one nuclear warhead, marking it as a non-MIRVed system in contrast to later Soviet developments.[1][2] Western intelligence assessments pegged the warhead yield at approximately 600–750 kilotons, with a total payload mass of around 600 kg, optimized for the missile's three-stage solid-propellant architecture to balance range and destructive potential against hardened targets.[1][5] The RV followed a basic ablative design typical of 1960s Soviet reentry vehicles, without penetration aids or decoys, reflecting the RT-2's role as an early counterforce asset in hardened silos rather than a highly survivable or evasive platform.[2] Deployment records indicate no variants with multiple independently targetable reentry vehicles (MIRVs) were fielded, limiting the missile to single-point strikes despite its strategic deterrence intent.[1]General Specifications
The RT-2 (8K98), designated SS-13 Savage by NATO, was a silo-based, three-stage, solid-propellant intercontinental ballistic missile (ICBM) developed by the Soviet Union.[1] It featured inertial guidance with a gyro-stabilized platform and was designed for single-warhead delivery.[1] The missile employed a hot-launch, mortar-style ejection from its silo.[1] Key specifications varied slightly across modifications (Mod-1, Mod-2, Mod-3), reflecting iterative improvements in performance and reliability.[1]| Parameter | Value (Mod-1/Mod-2/Mod-3) |
|---|---|
| Length | 21.27 m / 21.265 m / 21.13 m |
| Diameter | 1.95 m / 1.95 m / 2.0 m |
| Launch Weight | 46.1–51 t / 51.6–51.9 t / 50 t |
| Stages | 3 (solid-propellant) |
| Range | 9,400–9,500 km / 10,000–10,200 km / 10,000 km |
| Payload Weight | 0.545 t / 0.6–1.4 t / 0.5–1.0 t |
| Warhead Yield | 0.6–1.5 Mt (Western est.); 0.75–1.0 Mt (Russian est., Mod-1) |
| CEP | 1,850–2,000 m / 1,500–1,800 m / N/A |