OverviewThis specification defines the technical architecture for a standardized Archive of Redundant Coding (ARC)—a passive, radiation-hardened payload designed to carry a comprehensive copy of the terrestrial genome library as a secondary payload on routine orbital launches. The ARC is the engineering implementation of the “information redundancy” strategy described in Reynolds (2026, ‘Single Address’) [1], with the full technical framework presented in Reynolds (2026, ‘Seeding the Void’) [2]. This document identifies the absence of any off-site backup of Earth’s 3.5-billion-year genetic library as a critical common-mode vulnerability and specifies the payload architecture to address it. The specification addresses physical architecture, radiation shielding, six independent encoding pathways, thermal behavior, mission profiles, planetary protection compliance, and cost. All design decisions are governed by a single principle: the archive must not reproduce, at the encoding or hardware level, the single-point-of-failure architecture it is designed to mitigate at the planetary level.