Lunarport: A proposed Lunar-resource station to expand deep-space travel horizons

Deep-space travel is limited by the costly voyage to leave Earth's atmosphere and gravitational pull. The volume of propellants per unit mass of the payload required for that segment constrains the payload size and payload destination. To circumvent that limitation, this paper presents the feasibility of a refueling station using Lunar resources, called Lunarport. On Earth's moon, an unmanned station will robotically mine, produce, and store fuel and oxidizer from water ice at the poles. A first-stage-like rocket, called the Lunar Resupply Shuttle (LRS), stationed there and propelled with mined resources, will launch and dock with a passing payload-carrying rocket. That rocket will be reloaded with propellants by the LRS, after which the LRS will detach and the payload-carrying rocket will continue its journey to its desired trajectory. The LRS will wait in Lower Lunar Orbit (LLO, to avoid deterioration from Lunar regolith) until another payload-carrying rocket is launched from Earth, after which, the LRS will land back on the Moon, reload propellants, and launch again to dock with the next rocket. This paper elaborates on Lunarport, presenting proof-of-concept calculations of the increase in payload size sent to various payload destinations as well as a cost-benefit analysis. By way of example, NASA's Space Launch System (SLS) en-route to Mars that refuels at Lunarport can have a payload approximately 17 metric tons (mT) heavier than one traveling straight to Mars from Earth. This increase of more than 50% [1] is just to a relatively nearby planet-Mars. Sending a payload farther offers larger benefits with Lunarport. Wear-and-tear issues the port will be subjected to are also discussed. A full analysis of Lunarport will be done during the 2017 Caltech Space Challenge sponsored by Airbus Defence and Space held from March 26-31, 2017.