H.GR-21 Thureos

H.GR-21 Thureos
Type	Intercontinental Ballistic Missile (ICBM)
Place of origin	Willink
Service history
In service	2021-present
Used by	Willink
Production history
Designed	2009-2021
Manufacturer	Institoúto Stratigikón Naftikón Erevnón
Unit cost	$50-70 million USD
Produced	2021-
No. built	240
Variants	H.UR-3 Oceanus
Specifications
Weight	209.5 to 231.5 tons
Length	119ft
Diameter	11ft
Warhead	high yield thermonuclear, MIRV, MARV, EMP, high yield thermobaric, anti-fleet, tactical nuclear, biological/chemical, decoy
Detonation mechanism	Ground burst, air burst, kinetic
Blast yield	up to 150mt depending on configuration
Propellant	Three-stage solid-fuel
Operational range	15,000-18,000 km
Speed	Mach 20+
Guidance system	INS, GNSS, TERCOM, Autonomous, Celestial
Accuracy	5-10 m CEP
Launch platform	Silo, TEL, Submarine (SLBM)

The H.GR-21 Thureos is a superheavy intercontinental ballistic missile and FOBS platform developed by the Willinkian conglomerate and defense contractor Institoúto Stratigikón Naftikón Erevnó (ISNE). Designed following Willinkian experience utilizing rocket systems from Zeppelin Manufacturers and Izistan, the Thureos is designed as a highly adaptable system for strategic and tactical needs, operable from several launch mediums, and mounting a variety of payloads. Alongside the ARES Group Skyrend spaceplane and sixth generation ISNE Bélos air superiority fighter, the Thureos stresses the current limits of Willinkian material and weapons engineering; a protracted development process lasting twelve years and nearly 30 billion dollars resulted in a system that figures among the most capable strategic deterrents in the known world. The Thureos was accepted into service in 2021, and as of 2024, 240 examples have been produced.

Design

The Thureos large size and high throw weight of 12 metric tons classify it as a superheavy ICBM; it is variously designed to deliver large-yield thermonuclear strikes on large population centers and military targets, as well as saturation attacks; the Thureos is capable of carrying four large hypersonic guide vehicles, permitting a host of different payloads to be delivered. Willink utilized nuclear weapons for the first time in combat in 2005, destroying military and civilian targets in Saharistan with Menavlon ICBM's in response to a Saharistani nuclear strike of the city of Nesha which killed over one million people. Given the vastly larger scale of nations, urban centers, and military-industrial facilities in Haven, Gholgoth, and Greater Dienstad, a more weighty, sophisticated, and multifaceted delivery platform was necessary. Willink further gained valuable experience operating Khan Class Heavy Ship to Ship missiles and various Izistani rocketry launch platforms, taking valuble lessons from some the region's cutting-edge of rocket science. The Thureos incorporates advanced materials, propulsion, and countermeasures to maximize its utility against large, technologically sophisticated adversaries.

Guidance

The H.GR-21 employs a sophisticated multimodal guidance suite to provide exceptional accuracy, survivability, and adaptability against countermeasures. The core of the Thureos guidance system is its Inertial Navigation System (INS), leveraging laser ring and fiber optic gyroscopes as well as Willink's first military application of quantum accelerometers, providing a foundational navigation layer during the boost and midcourse phases that is resistant to jamming and electronic warfare. The second component of its navigation suite is its Global Navigation Satellite System (GNSS), augmenting the INS with data from both Willinkian and allied state's satellite constellations with real-time positional correction. This system uses various high-gain, multi-band GNSS antennas, software-defined receivers and anti-spoofing modules to defend against jamming and signal deception attacks and functions as a redundancy in the event of signal disruption.

The third element of the Thureo's guidance suite is its Terrain Contour Matching (TERCOM) system, utilizing synthetic aperture radar (SAR) to scan and identify terrain contours, with advanced image processors used to correlate live scans with stored terrain data. TERCOM enables the Thureos to navigate using pre-mapped terrain data, scanning surface features to ensure accuracy during its terminal phase, especially for land-based targets. This is especially important for its hypersonic glide vehicles, and is designed for low-level strikes and enhanced accuracy under GNSS-denial conditions, as well as to evade radar-based ABM discrimination by blending the vehicle’s trajectory with the landscape. The fourth element of the guidance suite is a Celestial Navigation System (CNS) failsafe, utilizing optical sensors track specific celestial bodies (e.g., stars or the sun) to cross-reference its position. High-speed onboard processors are employed for dynamic celestial mapping, and data is seamlessly integrated with INS data for fusion of positional fixes. This system also provides enhanced accuracy during the exoatmospheric midcourse phase, when no terrain or GNSS signals are available, and provides further ability to avoid full-measure jamming by using constant fixed reference points.

The final element of Thureo's guidance is its Autonomous Guidance Systems (AGS) capable of real-time decision-making and adaptive flight corrections. This AI system integrates data from INS, GNSS, TERCOM, and CNS to optimize flight paths dynamically, and utilizes predictive trajectory mapping to identify and avoid interception threats. The AGS provides real-time evasion capabilities, particularly for hypersonic glide vehicles during atmospheric reentry. The system can adapt flight paths to counter enemy ABM systems by identifying and maneuvering around projected interception points, and enables target-switching capabilities, allowing Thureos to dynamically retarget based on battlefield conditions or evolving priorities after launch, and assists in defeating layered defense systems through unpredictable and non-ballistic trajectories, permitting evasion of predictive targeting systems used by ABM platforms. These systems create redundancy and interact simultaneously during flight; during the boost phase, the INS and GNSS systems dominate to ensure initial trajectory accuracy, during the midcourse phase, CNS and GNSS provide positional redundancy while TERCOM prepares pre-terminal navigation parameters, and during the terminal phase, hypersonic glide vehicles activate AI-based autonomous guidance, incorporating TERCOM and sensor inputs to ensure precision strikes while actively evading interception attempts.

Warheads and Loads

The H.GR-21 Thureos is engineered to deliver a diverse array of payloads, each tailored for specific strategic and tactical objectives. Below is a detailed overview of these payload options, their roles and utilities.

Hypersonic Glide Vehicles

The Thureos can mount up to four large hypersonic glide vehicles (HGVs) with adaptable payloads, permitting the platform near-unlimited flexibility. These vehicles detach from the payload bus during a separation phase (either in sub-orbital or fractional orbit) where the post-boost vehicle stabilizes using cold gas thrusters and on-board reaction wheels; payload release is timed precisely based on pre-programmed targeting data or mid-course updates. Each HGV detaches sequentially to ensure proper spacing and trajectory divergence. After detaching, the HGVs execute a controlled pitch-over maneuver to transition from ballistic drop into an aerodynamic hypersonic glide. This transition is enabled by advanced aerodynamic shaping and high-temperature-resistant materials, allowing the HGVs to “skip” along the upper atmosphere, maintaining hypersonic speeds (Mach 10–20). To complicate interception, the PBV may deploy multiple HGVs with divergent trajectories, sending them toward widely separated targets or converging on a single region from different angles. Simultaneously, the PBV may itself deploy decoys and sensor-jamming stressors to mask the real HGVs.

The HGVs utilize a skip-glide flight pattern, where they repeatedly "bounce" off the denser layers of the upper atmosphere. Each skip reduces atmospheric drag while maintaining hypersonic velocity. This trajectory enables the HGV to remain below the detection envelopes of space-based early warning systems while staying above the reach of most ground-based interceptors. Unlike traditional ballistic warheads that re-enter steeply, HGVs descend at low-altitude, shallow trajectories. They skim the atmosphere in the upper troposphere or lower stratosphere, evading ground-based missile defense radars designed to detect higher ballistic arcs. Terminal speeds remain hypersonic, with velocities between Mach 8–12, ensuring reduced interception windows. Equipped with aerodynamic control surfaces and reaction control systems, HGVs can execute sharp course corrections during flight, deviating unpredictably from their nominal path. This includes zig-zagging maneuvers, S-turns, and high-G lateral rolls, complicating interception algorithms that rely on predictive targeting.

The HGVs utilize both passive and active measures to evade interception systems: their ability to alter trajectories in-flight ensures that predictive interception solutions cannot account for dynamic adjustments, and they can execute last-second dives or shallow-angle rolls during terminal descent, overwhelming even advanced hit-to-kill interceptors such as THAAD. Each HGV carries a potent suite of penetration aids (PENAIDs): hot-burning IR flares that mimic the hypersonic heat signature of the real vehicle, saturating heat-seeking interception systems, Small, lightweight chaff clouds to confuse enemy tracking radars and expand radar signature clutter, and dedicated onboard electronic warfare (EW) systems to emit broad-spectrum jamming signals that disrupt enemy fire control radars and interception guidance links. The Thureous often also deploys numerous ballistic decoys, both in its MIRV configuration and in its HGV configuration; a combination of dummy warheads and smaller maneuvering decoys are released alongside real HGVs, saturating defensive systems with false targets.

By deploying HGVs from widely spaced PBVs or conducting independent maneuvering, the flight paths of the vehicles converge on targets from multiple vectors. This stresses defensive coverage zones, requiring simultaneous interceptions. The high-G maneuvering and skip-glide behavior of the HGVs make them resilient to direct kinetic kill interceptors, enhancing the efficacy of the launch by preventing defenders from relying on traditional "predict-and-fire" solutions. As the HGVs close within the terminal range (sub-50 km altitude), they perform a final set of high-speed evasive maneuvers to defeat last-ditch interception systems. TERCOM and AI-assisted guidance solutions ensure the HGVs achieve near pinpoint accuracy despite complex maneuvers, permitting the Thureos to maintain an extremely narrow circular error of probability in line with "next generation" delivery platforms such as the LGM-35 Sentinel. Whether equipped with MIRVs, EMP warheads, tungsten kinetic penetrators, or other payloads, the HGVs deliver their strike with hypersonic impact energy.

FOBS

The Thureos is designed with the capacity to be used for fractional orbital bombardment, as a response to doctrinal observations in large combined armed operations; Willink observed Space Union use a barrage of space and surface based weaponry to eliminate critical Saharistani infrastructure during the 2005 conflict, and again observed Aequatio engage in a vast space denial campaign against Allanea at the onset of hostilities during the Presto-Clandonian War in 2009. Accordingly, the Thureos was design with delivery mechanisms in line with a large-scale, multi-spectrum, combined arms conflict, where space-based platforms and resources would almost certainly be under immediate attack by hostile nations. Accordingly, the Thureos is designed with a combination of maneuverability, evasion, and dynamic orbital deployment making it uniquely suited to survive and operate in a contested or degraded space environment. FOBS allows the missile to place warheads—or specialized payloads—into partial low-Earth orbits, circling the globe briefly before deorbiting to strike targets with minimal warning. Whereas static space platforms (such as Rods of God, or space-based energy weapons) follow consistent orbital patterns that can be tracked and targeted, Thureos FOBS payloads are instead dynamic, leveraging fractional orbits, reentry maneuvers, and hypersonic glide paths to bypass static defenses. FOBS payloads provide several strategic benefits; they preserve first strike capability, even if space systems have been degraded or destroyed, sidesteps existing ballistic missile defense (BMD) systems concentrated around predictable orbital trajectories, can itself be used in an anti-satellite weapon , targeting enemy space constellations using kinetic kill payloads, disrupting reconnaissance and communication systems, and permits a single Thureos launch to target multiple theaters of operation with different payload types, allowing simultaneous strategic and tactical strikes.

Once in partial orbit, Thureos payloads use miniature attitude thrusters and thrust-vectoring to maneuver unpredictably and jink. This enables course adjustments to evade ASAT weapons or interceptors, sudden deorbiting maneuvers to exploit weakened detection and tracking infrastructure, and re-entry timing manipulation to saturate defenses during gaps in radar coverage. Thureos deploys advanced decoys, multi-spectrum chaff, and jammer pods during its orbital phase to overwhelm enemy tracking systems. This creates chaos for residual space-based or ground-based interceptors attempting to lock onto the warheads. This dynamic mechanism of deployment both allows Willink to react quickly to assaults on its own space infrastructure and deploy payloads urgently to low-earth orbit to take advantage of degraded enemy space assets in offensive operations.

Propulsion

The Thureos utilizes a three-stage, mixed fuel propulsion system. The first stage consists of a lightweight composite casing using carbon-carbon reinforced with ablative liners, producing 3,500 kN of thrust, fueled by a PBHT-based solid propellant combined with metalized additives. The second stage consists of a composite-aluminum structure with active thermal cooling, mounting an array of decoys, chaff, and electronic jammers. This stage produces 1,500 kN of thrust, fueled with a solid propellant mixture optimized for mid-course acceleration. The third stage consists of a maneuverable post-boost vehicle housing up to 20 MIRVs or (up to) 4 hypersonic glide vehicles, producing 250 kN of thrust, and fueled by liquid bi-propellant for fine maneuvering and MIRV deployment. The glide vehicles of the Thureos employ ablative materials, carbon-carbon composites, and ultra-high-temperature ceramics to survive temperatures above 2,000°C during reentry. The HGV's of the Thureos are capable of recorded speeds of Mach 20+ (~25,000 km/h) during reentry and Mach 10–15 (~12,000–18,000 km/h) while in glide velocity.

Delivery platforms

The Thureos was designed to replace all existing intercontinental platforms in the Willinkian arsenal; although technically designed to permit silo launch, in practical application nearly all deployments are provided by way of transporter erector launcher; the vast distances in the world (Haven, for instance measuring some 40,000 kilometers across) limit the strategic effectiveness of static missile launches, and with the proliferation of near-global reconnaissance assets, static silos become predictable targets. Advanced adversaries could preemptively identify and destroy silos with orbital surveillance, kinetic strikes, or saturation attacks. Accordingly, the Thureos is almost entirely deployed on mobile platforms, providing strategic depth and unpredictability. Mobile systems such as Thureos permit Willink to disperse its nuclear deterrent, avoiding the concentration of assets. This reduces the risk of catastrophic losses during a first strike and ensures second-strike capability remains intact.

The Thureos, despite its large size has been adapted for submarine (and, conceivably, superdreadnought use), under the designation H.UR-3 Oceanus, which is expected to enter service in the first quarter of 2025.