Complexity Evaluation of an Environmental Control and Life-Support System Based on Directed and Undirected Structural Entropy Methods

Abstract

During manned space missions, an environmental control and life-support system (ECLSS) is employed to meet the life-supporting requirements of astronauts. The ECLSS is a type of hierarchical system, with subsystem—component—single machines, forming a complex structure. Therefore, system-level conceptual designing and performance evaluation of the ECLSS must be conducted. This study reports the top-level scheme of ECLSS, including the subsystems of atmosphere revitalization, water management, and waste management. We propose two schemes based on the design criteria of improving closure and reducing power consumption. In this study, we use the structural entropy method (SEM) to calculate the system order degree to quantitatively evaluate the ECLSS complexity at the top level. The complexity of the system evaluated by directed SEM and undirected SEM presents different rules. The results show that the change in the system structure caused by the replacement of some single technologies will not have great impact on the overall system complexity. The top-level scheme design and complexity evaluation presented in this study may provide technical support for the development of ECLSS in future manned spaceflights.

Life Cycle Cost Model for Life Support Systems of Crewed Autonomous Transport for Deep Space Habitation

“…The decision on the architecture of life support systems must be made at the early stages of their creation, evaluating their effectiveness in terms of cost, reliability, and sustainability [37]. For this purpose, it is advisable to apply life cycle costing models that estimate the costs associated with various components of the system, including the costs of development, production, operation, and maintenance [38][39][40].…”

Evaluation of Aircraft Environmental Control System Order Degree and Component Centrality

“…Wang et al used this method to evaluate systems with network structures quantitatively and to evaluate the order degree of the organization of a power regulatory institution [29]. In terms of thermal systems, Yang et al conducted research on an environmental control and life support system with a hierarchical structure inside a spacecraft-using the SEM to calculate the order degree of the system-and evaluated its complexity quantitatively [30]. Yang et al conducted structure entropy analysis on a series/parallel two-wheel ACS and integrated/split four-wheel ACS with traditional engine bleed air and compared the order degree of each system [20,31].…”