Modeling the Impact of Water Systems Configuration on the Overall System Health of a Human Space Habitat

This paper discusses the impact of water systems configuration on the overall system behavior of an advanced life support system. Parameters are defined to describe the overall system state. A model that consists of four different water tanks is built to simulate water usages and water flow through these tanks. The methodology developed in this model minimizes the initial amount of clean water, treatment efficiency and treatment capacity required. The relationship among these three varaibles is studied and expressed in mathematical form, while keeping the system state at “Desirable” at all times. Two schedules, 1-shift and 2-shifts crewmember schedules are examined with respect to these three variables. Results from the study shows a counterintuitive observation that a multiple-shift schedule may not be as effective as a single shift schedule as far as water usage is concerned. Another more intuitive observation is that a lower treatment efficiency requires a larger treatment capacity in order for the system to operate at a desirable state. Relationships among the initial amount of clean water, treatment efficiency and treatment capacity are expressed in terms of 3^rd-order polynomials. Because these variables can have a significant impact on the overall ESM of the system, this study provides a tool for minimizing ESM by evaluating trade-offs among these variables. Results from this study also serve as the base for future trade-off studies.