Future Model for Efficient and Advanced Space Transportation: Exploration and Perspectives

Current space transportation employs a multistage rocket system to deliver the payload to its destination in a single launch, and this integrated model significantly constrains payload capacity for medium-high earth orbits and deep-space missions. However, the medium-high earth orbits and deep-space domains are anticipated to become the next exploration and utilization frontier, which needs large payload capacity and low-cost transportation as support. This study proposes a decoupled design for space access and in-space transfer in a medium-high earth orbit or a deep-space mission. This design introduces a novel in-space transfer transportation system enabled by cryogenic propellant refueling in orbit. In the proposed model, Earth-to-orbit vehicles are responsible for space access, while in-space transfer vehicles handle orbital transfer. This separation allows for independent optimization of vehicle designs according to their specific flight environments. Additionally, on-orbit refueling enables long-term, reusable operations for in-space transfer vehicles. The advantages of the new model are analyzed, demonstrating significant improvements in payload capacity for medium and high earth orbits, as well as substantial reducing transportation costs, holding great practical significance. Relevant design challenges associated are also given, providing a reference for subsequent in-depth researches.