The logical core architecture

Molecular nanotechnology (MNT) promises new functions for engineered systems, such as fairly general purpose fabrication and disassembly. Systems designed afresh to take advantage of these new functions should offer original architectures. One compelling example is the 'logical core architecture', which uses subsystems providing general purpose manufacturing to enable a long-lived, very flexible system. This paper provides motivation for the logical core architecture, discussing systems architecting, the inclination of MNT to support polymorphic systems and the implications of using dynamic remanufacture of on-board components for reliability. It describes in detail the logical core architecture, which comprises four levels, the logical core, the physical core, the surge layer, and the external interface layer. The functions of the subsystems in each of these layers are presented. To illuminate the architecture's capabilities, example operations are presented. Several are space mission profiles for systems using a logical core architecture for such tasks as multimode trajectories and asteroid mining, and several illustrate more general capabilities and flexibilities of the architecture. Basic equations are derived for reliability via on-board remanufacture of subcomponents and for surging functional capacity. The prospect of fundamentally new operating modes raises interesting questions regarding appropriate operating policies. Initial observations are offered on these novel problems. The paper concludes with a discussion of important open questions, including appropriate directions for further stepwise refinement of the architecture.