Systems Engineering of Using Sandbags for Site Preparation and Shelter Design for a Modular Lunar Base

The next major milestone in space development will be to establish a semi-permanent or permanent human presence on the Moon. The Moon will become a springboard for future efforts to advance a Cislunar space economy and advance the colonization of Mars. We expect a lunar base camp rated for humans that is capable of in situ resource utilization (ISRU) will contain several facilities, such as stations for power, mining, robot operations, asset tracking, communications, material processing, geological survey lab, service, and repair station and launch/landing pads. Various parameters will be involved in the design of each facility. With so many parameters present, arriving at an optimal solution for the design of the lunar base requires the following: (1) Identifying the critical parameters involved; (2) Formulating the empirical relationships between the identified parameters; (3) Performing optimization utilizing the empirical relationships found. An early lunar base is expected to be modular, with lessons learned from the construction of the International Space Station (ISS). Site preparation tasks had initially been envisioned to be done using astronauts. However, the lunar surface is harsh, and performing dull, dirty, and dangerous tasks such as site preparation puts astronauts at risk. A compelling alternative is using robots to perform site preparation and base construction ready for human astronauts to live. In this paper, we identify the different parameters involved in constructing a modular lunar base with a focus on ISRU and aim to arrive at the empirical relationships between them. We perform a case study on a modular base with each module constructed with sandbags. Sandbags offer the lowest cost of entry towards surface construction. Sandbags are relatively easy to assemble into shelters and support structures and can be adapted to various lunar surface conditions. Sandbags structures do not require water or heat for construction. Obtaining enough water to produce the paste needed for additive building structures on the Moon is a significant challenge. In contrast, solar sintering requires high energy and relatively complex facilities to generate significant amounts of solar energy to be used in sintering and additive manufacturing. We perform a detailed analysis of sandbag structures for constructing a lunar base and critically analyze the shortcomings and what needs to be done to overcome them. First, we list out the critical parameters for each module (independent variables) and identify the interfacing requirements between modules to arrive at the dependent and derived variables. Then we use these variables to arrive at the relations to the size of the different modules and, consequently, the entire base itself. These relations may be used as a tool to arrive at configurations for lunar bases based on different objectives and requirements.