Conceptual system design of a Habitat-Simulator (HabSim) for the operation of the Lunar Agriculture Module-Ground Test Demonstrator (LAM-GTD)

Kurzfassung

This thesis evaluates an Habitat-Simulator (HabSim) draft design for the Lunar Agriculture Module- Ground Test Demonstrator (LAM-GTD), a project from the German Aerospace Center (DLR) together with the Canadian Space Agency (CSA). The LAM-GTD consists of two modules, the Airlock Module (ALM) and the Ground Agriculture Module (GAM), which are connected via a connection ring. The objective of this project is to validate the GAM design for transferability to a flight-ready and space-qualified Lunar Agriculture Module (LAM). The GAM is a space greenhouse and as such, it shall serve as a Bio-Regenerative Life Support System (BLSS). Since the ground test demonstrator is an on-earth project and therefore won’t be connected to a real space habitat, this habitat must be simulated. Therefore, the HabSim, as a hardware device, shall fulfill the purpose of simulating an imaginary space habitat to the LAM-GTD, while measuring all the resource flows between the ALM and the GAM. For a basic understanding of how space habitats and BLSS work, the thesis summarizes the most recent and also long-term functional technologies. This also includes a breakdown of BLSS. Since there existed different ideas on what HabSim shall be capable of, the thesis first comes up with an evaluation of several concepts that discuss the scope of the HabSim’s features. As a result of the evaluation, it is decided to separate the HabSim into two systems: A Measuring Subsystem, which measures the resource flows between the ALM and the GAM, and an independent Simulation Subsystem (SimSub), particularly simulating a realistic air exchange between the ALM and an imaginary space habitat. Based on the evaluation, one concept is selected, and the corresponding requirements are set up. Due to the concept decision and in close agreement with the mission level and the university supervisor, it was decided to constrain further development to the Measuring Subsystem. Based on the requirements, a system architecture for the Measuring Subsystem is designed, distinguishing the necessary sensors, their positioning, and piping/wiring. Subsequently, the thesis includes a component preselection, followed by a 3D model of the Measuring Subsystem, and eventually the implementation in a predefined envelope. Overall, the thesis shows that a separation between measuring flows and simulating a space habitat is meaningful. Furthermore, several issues in the current system maturity of the LAM-GTD were shown, particularly concerning the ALM. Especially in a low-pressure environment, the choice of usable Commercial Off-The-Shelf (COTS) sensors is limited. With the aid of the component preselection and the 3D model, it was demonstrated that the Measuring Subsystem fits in the reserved envelope and the connection ring between the ALM and the GAM does not need to be adapted. The material costs for the system were calculated to be around 45,000 €.