The Cascading SWaP Revolution: How Admissible Software Eliminates Hardware Overhead from Orbital Substrates to Terrestrial Edge

Arcstone Computational Spine (ACS) — Academic Whitepaper Suite (Paper 9 / SWAP01) In high-assurance avionics and orbital systems engineering, physical hardware reliability is traditionally achieved through brute-force Triple Modular Redundancy (TMR). This paper demonstrates how transitioning to an Admissible Execution Model via the Admissible Computational Spine (ARC-SPEC-2026-SPINE-01) eliminates active voting circuits and redundant hardware buses. By enforcing a zero-branch, constant-time software invariant matrix Π(S) inside non-cacheable Tightly-Coupled Memory (TCM), mathematically invalid state vectors are rejected locally prior to state mutation. Speculative Write Buffers (SWB) isolate uncommitted mutations while Zero-Order Hold (ZOH) actuator latches preserve guidance phase margins within Maximum Tolerable Delay (MTD) budgets. This yields a cascading SWaP reclamation across spacecraft and terrestrial edge platforms while satisfying DO-178C DAL A and ARP4761 catastrophic failure mandates (< 10^-9 PFH). Linked to Primary Master Anchor (10.5281/zenodo.22665852) and the arcstone-continuity-core open-source repository. Core Mathematical & Hardware Invariants:• Invariant Matrix Lock: Π(S) validation in non-cacheable Tightly-Coupled Memory (TCM)• Temporal Override Floor: τ_override ≤ 11.99ms• Failure Probability Floor: System Safety Hazard Allocation < 10^-9 PFH (DO-178C DAL A / ARP4761)• Dominance Lattice: FAIL ≻ FREEZE ≻ PWC ≻ PASS• Cₒₚₛ = 0 (Zero Operational Drag)• Data_Egress_Sensitive = 0 (Zero Sensitive Egress)