In model-based systems engineering, system architectures often have to make compromises to meet hard constraints of functional and extra-functional requirements while optimizing for a target objective. Design space exploration (DSE) techniques have been developed to automatically propose candidate architectures over an extremely large design and configuration space. (1) Meta-heuristic exploration algorithms are often used to provide practical, best-effort solutions for DSE, but they lack any guarantees of completeness or optimality. (2) Logic synthesis based approaches may offer strong theoretical guarantees, but frequently face scalability issues. In the paper, we propose two logic solver-based approaches to evaluate complex design spaces by using partial models in order to find an optimal solution with respect to performability objectives. One approach uses performability analysis as a post-filtering of valid system architecture candidates, while the other approach uses performability analysis for guiding the actual search over partial models. We evaluate both approaches on an interferometry mission architecture case study using view transformations for performability analysis and compare our approach with a well-known DSE framework based on meta-heuristic search.