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-
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 an 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.

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 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 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, 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, designed to assist 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.

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.