Observability Limits in Coherence-Constrained Planetary Reconstruction: The Role of Population Accumulation

Coherence-constrained backward reconstruction frameworks, such as the Synthesis & Estimation Architecture (SEA), reduce admissible historical trajectories by enforcing global consistency across heterogeneous observables. While powerful in Earth system applications, their extension to planetary and astrophysical contexts raises distinct questions of observability and identifiability. Here we examine whether residual uncertainty classes identified in Earth-based SEA applications admit measurable analogs in space, and whether accumulation of SEA reconstructions across many systems can progressively constrain these uncertainties. We identify eight residual uncertainty classes specific to space and planetary systems, evaluate their measurability under current and foreseeable observational regimes, and distinguish which classes can be narrowed statistically through population-level accumulation versus those that remain structurally irreducible even at large N. This work provides a principled framework for interpreting SEA outputs in space contexts and clarifies which uncertainties reflect fundamental observability limits. This paper forms part of a broader series developing the Synthesis & Estimation Architecture (SEA) as a domain-general framework for coherence-constrained reconstruction and observability-limited inference across Earth, planetary, and astrophysical systems.