Lunar Cargo Transportation (LuCaT): Semi-Autonomous Vehicle With Suspended Cable and Solar Power

The movement of cargo on the lunar surface has been hindered by the effects of the lunar environment and the capabilities of current vehicles. As larger scale infrastructure is needed, and the movement of in-situ resources and general cargo is required with an anticipated increased human presence, new vehicles will need to be designed that can survive in the lunar environment and transport massive materials or cargo over long durations without significant upkeep. Low speeds of four-wheeled lunar vehicles will also need to be addressed as most robotic lunar roving vehicles move very slowly, and the manned lunar roving vehicle from the last lunar landings, could only safely achieve a max speed of eight miles-per-hour. To solve these identified problems a semi-autonomous suspended transportation system is proposed that can carry more cargo, travel faster, and operate longer than current lunar vehicles.

A conventional vehicle build is used that involves a chassis, wheels, and drivetrain while taking inspiration from earth based aerial tramways. The wear of regolith lunar dust and the difficulties in traversing the lunar surface are subverted by using a system suspended by cables so that wear on essential mechanical components is mitigated. Catenary sag analysis is performed to determine the optimal length of the cable track taking into consideration the thermal expansion and contraction caused by solar exposure and the lack thereof, as well as considering the weight of the cables and transportation system. Since the system does not require the vehicle to traverse the rough terrain of the lunar surface, the speed of the vehicle is found to be above the maximum speed of the lunar roving vehicle and robotic rovers. By implementing a drivetrain system powered by solar energy. long term power generation and vehicle operation is achieved in the south polar region near Shackleton crater, a location that remain in sunlight for significant amounts of time. A solar array concept based on a cylindrical shape is promoted in reducing the number of parts required because this south polar region the sunlight is incident from one only side. Because of the extreme high and low temperatures of the moon, transient and steady state thermal finite element analysis was performed for various solar exposures and multi-layer insulation was sized using methods for thermal shielding. To protect the internal components of the vehicle and the chassis a lightweight shell is modeled. A thermal control system is designed to manage the battery waste heat, utilizing optical solar reflectors and a fluid cooling system, sized using radiative and convective heat transfer equations. Furthermore, a block diagram is created to demonstrate the control method of the transportation system and a cargo container is sized to accommodate a given amount of lunar water ice to demonstrate the payload transportation capabilities near Shackleton crater.