HOW THE LUNAR SPACE TUG CAN SUPPORT THE CISLUNAR STATION

The Lunar Space Tug is a sustainable transportation system able to rendezvous with a target body in the Low Earth Orbits (LEO) environment, assess its current position, attitude and operational status, capture the target and move it to the Cislunar space where a new Deep Space Habitat (DSH) will be settled. Thanks to the adoption of an Electric Propulsion Subsystem based of Hall Effect Thruster (HET) clusters, the LST can save fuel to the detriment of much longer transfer time to deliver the unmanned cargo to the DSH. The LST is designed to accomplish several applications, from cargo transfer, to on-orbit assembly and samples return. Being a reusable transportation system, one of the main issue is related to the on-orbit refueling to sustain the LST during its operational lifetime. Each mission scenario shall take into account the effects related to refueling operations according to mission requirements and constraints. Considering the whole mission scenario in which the LST will operate, this paper focuses on mission analysis and conceptual system design, including typical systems budgets, like delta-V, mass and power budgets. In addition, according to the transfer duration and the needs of the Cislunar station, a preliminary trade-off analysis has been accomplished to investigate the possibility of using a fleet of LST instead of one single LST, taking onto account safety, reliability, costs and operations issues. Main results are presented and discussed, and main conclusions are drawn.