Threat and Hardness Assessment of Nuclear Operational Survivability (THANOS) Upgrade

Probabilistic survivability analytical tools for nuclear mission planning are a major gap in the U.S. nuclear strategy. The most recent Nuclear Posture Review (2018) underscores this critical role, “For more than six decades, U.S. officials have emphasized the need for U.S. nuclear capabilities, including NC3, with the attributes necessary to deter adversaries, assure allies, and achieve U.S. objectives should deterrence fail. They have called for the survivability and flexibility of U.S. nuclear forces to provide the United States with multiple options to deter effectively and respond as necessary to different threats and circumstances. This requirement is now magnified by the need to tailor U.S. strategies to a broader range of adversaries and contingencies and to hedge against unanticipated developments.” Survivability is a weapon system attribute that has not been addressed. The Peacekeeper system performed initial survivability assessments in 1991, however, the tools, codes, and documentation developed for this analysis have long since atrophied. Survivability quantifies a probability that a weapon system will survive a certain environment induced by a specific scenario. ICBM survivability analysis must incorporate statistical analytics to perturb the input conditions, the inherent tolerance effects from design, unit-to-unit variability, reliability performance, and operational variations. THANOS (Threat and Hardness Assessment of Nuclear Operational Survivability) software is the only available statistical survivability tool developed for this analysis. It allows for design fragility assessment, statistical variability in the input conditions, and operational variations. The current capability of THANOS is limited to ballistic phase survivability analysis, but an end-to-end analytic capability, including In-Silo survivability, is needed with needed. The In-silo phase of an ICBM weapon system incorporates the greatest number of subsystems, is subject to relatively high hostile nuclear environments (radiation, EMP, blast, ground shock, debris, nuclear fallout), and covers 9600 square miles of missile fields plus the Hardened Intersite Cable System. The survivability of these facilities is critical to support the nuclear planning factors for the warfighter. Quantifying In-silo survivability will also provide much needed data for fratricide avoidance, CONOPs planning, damage expectancy, cost-to-harden studies, capability comparison with other systems, and trade space analytics for acquisition program design trade-offs. THANOS has been successful with the ICBM Fuze Program to analyze the effects of certain ballistic fratricide environments and whether a particular component design could relax a hardness requirement prior to final qualification. Similar evaluation capability is needed for future ICBM modernization programs to inform the acquisition strategy about cost tradeoffs to harden systems against varying levels of nuclear effects.