The conventional approach to designing space habitats by placing the exterior primary structure, the interior secondary structure, and the outfitting packages ahead of the Environmental Control and Life Support System (ECLSS) imposes dire inefficiencies upon the ECLSS. This tradition forces the packaging of ECLSS elements to fit into predetermined racks or panelized compartments. The design and dimensions of these accommodation spaces are completely arbitrary in relation to the optimal form, configuration, and size of the ECLSS elements. The availability of rack- or compartment-based accommodation spaces forces the ECLSS distribution to spread out among multiple modules, increasing the distances between elements, thereby increasing pump and fan sizing and power requirements. Compelling this complex equipment to squeeze into a priori sized rack volumes makes maintenance much more difficult for ECLSS equipment and so increases the failure rate. This "bash to fit, paint to match" philosophy leads invariably to profound inefficiencies and dysfunctionalities in the design, distribution, engineering, and installation of crucial life support elements. The underlying "Don't size the box/fit the box" approach also leads to difficulties in cleaning, maintaining, and servicing the ECLSS. This paper suggests a different approach in which the design, engineering, installation, and location of the ECLSS takes precedence before all the other systems. Certainly, all the other systems bear their own importance, but none will be so critical for sustaining human life in hostile space environments. Therefore, this paper explicates the key considerations for designing the ECLSS as the precursor for all the other systems, unimpaired by other system's decisions. Then it addresses the role of structures, interior outfitting, pressure vessels, power, thermal control, and all the other systems and subsystems.
Cohen et al. (2024) studied this question.