Leveraging System-of-System Modeling to Explore Massive Reusability for Cislunar Missions

One of the most exciting developments in commercial space has been the growing amount of reusability in launch systems for cislunar space accessibility. Given this context, this paper models the architecture of near-term collaborative cislunar exploration missions by developing and demonstrating the use of a Model-Based System-of-Systems (SoS) Engineering approach (MBSE) to such problem. The proposed mission architecture aims to enable frequent missions to the Moon at a lower cost than previous mission architectures, such as the Apollo program, by implementing reusable mission elements. The goal of this investigation, then, is to construct a novel framework using MBSE and demonstrate its application by analyzing the trade-off between propellant-motor choice and the degrees of reusability among systems in the Lunar Gateway to lunar surface transit environment. More specifically, Object-Oriented Programming of mission architectures and operations was implemented to estimate mission cost and fuel consumption considering several propulsion systems and refueling strategies. Using the novel methodology proposed, the MBSE diagrams provided valuable high-level abstraction checkpoints that reduced mission design iteration complexity and provided simpler lexicon for multiple stakeholder viewpoints. Additionally, three motors were identified as the most interesting options to minimize mission cost, namely Vinci, Zefiro-9A and XLR- 132, and a proof-of-concept was also developed for the investigation of the effect of refueling strategies in the mission cost, where different portfolios and launch vehicle payload capacities were compared. An estimate of 3 to 4 cycles of transfers from the Gateway to the Moon and back was calculated as the necessary threshold to make the use of a Refueling Element more economical, providing an additional application of the framework to a distinguished emergent factor of the SoS to the mission analyst.