The Sentinel Papers — SPK-07 — Hard Cliffs: Workforce, Propellant, and the 2028 Decision Point

The LGM-35A Sentinel ICBM program's 2024 critical Nunn-McCurdy breach obscured a parallel crisis: the workforce and industrial base required to sustain Minuteman III through 2050 while fielding Sentinel cannot deliver under current funding and planning assumptions. The Air Force assessed 2050 operation as "feasible" only if entire subsystems — propulsion and guidance — are replaced (GAO-25-108466). Neither replacement program exists.

This paper proposes the Workforce, Supply Chain & Transition Continuity Kernel (WST-K), designated SPK-07 within the Sentinel Recovery Architecture. WST-K is a constraint-closure architecture comprising five computational components: WCRM++ (Workforce & Clearance Role-Class Model), CISG++ (Critical Item, Lifetime & Facility Risk Graph), DCTC++ (Deterrence-Constrained Transition Coupler), HCM (Hard Cliff Monitor), and PTLFM (PRP Talent & Location Friction Module).

Key findings:

• The Air Force has placed three logically incompatible positions on the public record: Minuteman III cannot be life-extended (2021 justification for Sentinel), Minuteman III can operate until 2050 (2024 response to Sentinel delays), and the subsystem replacements required for 2050 will not be funded (2025-2026 budget reality). Any two being true makes the third false.
• Propellant viability horizons (binder-dependent; earliest motors may already be approaching limits) and NS-50 guidance depletion (652 produced, ~100-140 spares remaining, test frequency already reduced to conserve inventory) create hard deadlines that workforce optimization cannot overcome.
• Nuclear-critical software requires approximately 3-4× naive FTE estimates due to NSCCA independent evaluation overhead (~2×) and cleared workforce churn (~50-60% efficiency) — compounding on CNWDI clearance gating and PRP lifestyle deterrence at remote bases.
• AMPAC Cedar City, UT — sole DoD-approved domestic ammonium perchlorate producer — is a documented single point of failure for all large solid rocket motor production across both land and sea deterrent legs.
• WST-K identifies a Threaded Continuity Regime (TCR) as the only feasible configuration satisfying all constraints simultaneously, requiring PRP-2 initiation by ~2028, guidance recapitalization, security certification pathway resolution, 15-20% Security Forces growth, and bounded Sentinel IOC slip from the post-restructure "early 2030s" baseline.
• There is no viable path that both maintains the statutory floor of 400 operational ICBMs (10 U.S.C. §9062(n)) and respects the Air Force's own 2050 feasibility conditions under current funding.

Version 2.0 incorporates corrections from two adversarial audit cycles and independent fact-verification across 40+ sources. Every claim traces to GAO assessments, Air Force documents, DCSA reporting, DoD IG audits, statutory text, federal contract records, or is explicitly labeled as a WST-K modeling output. No claim requires access to classified information.