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The replacement of refrigerant CFC-12 (dichlorodifluoromethane) with ozone-friendly HFC-134a (1,1,1,2 tetrafluroethane) in submarines has not only required changes in the refrigeration system but the life support equipment as well. Modifications to the refrigeration systems, catalytic oxidizer used for air purification and atmosphere analyzer were required to implement the conversion. Each of these modifications required careful laboratory and full scale testing to assure no adverse impact on the submarine equipment or crew.

In this paper, an aggregate system level modeling and analysis framework is proposed to facilitate the integration and design of advanced life support systems (ALSS). As in process design, the goal is to choose values for the degrees of freedom that achieve the best overall ALSS behavior without violating any system constraints. At the most fundamental level, this effort will identify the constraints and degrees of freedom associated with each subsystem and provide estimates of the system behavior and interactions involved in ALSS. This work is intended to be a starting point for developing insights into ALSS from a systems engineering point of view. At this level, simple aggregate static input/output mapping subsystem models from existing data and the NASA ALS BVAD document are used to debug the model and demonstrate feasibility.

An important function of life support systems developed for a long duration human mission to Mars is the ability to recycle water and air. The Bio-Regenerative Environmental Air Treatment for Health (BREATHe) is part of a multicomponent life support system and will simultaneously treat wastewater and air. The BREATHe system will consist of packed bed biofilm reactors. Model waste streams will be used for experiments conducted during the design phase of the BREATHe system. This paper summarizes expected characteristics of water and air waste steams that would be generated by a crew of six during a human mission to Mars. In addition to waste air and water generation rates, the chemical composition of each waste stream is defined. Specifically, chemical constituents expected to be present in hygiene wastewater, dishwater, laundry water, atmospheric condensate, and cabin air are presented.

This paper will report US Navy submarine philosophy and test experience with the emergency atmosphere control system. A vital aspect of emergency recovery within contained environments is the ability to maintain life while directing escape or awaiting rescue. Emergency atmosphere control differs from primary life support in several key areas. The primary atmosphere control system provides a habitable atmosphere so that the crew can live comfortably and work efficiently in an enclosed environment. Additionally the primary atmosphere control system controls chronic and acute toxicants to minimize both short and long term health consequences. For long duration missions, primary atmosphere control is generally regenerative and may include redundant components for reliability. The emergency life support system replaces the primary system in the event of a catastrophic failure.

This paper presents a system-level design and initial equivalent systems mass (ESM) analysis for a solid-phase thermophilic aerobic reactor (STAR) system prototype that is designed for a Mars surface mission. STAR is a biological solid waste treatment system that reduces solid waste, neutralizes pathogens, and produces a stabilized product amenable to nutrient reuse and water recovery in a closed life support system. The STAR system is designed for long-duration space missions or long-term remote planetary operations. A system-level design analysis for sizing a STAR process and the subsequent ESM based sensitivity analysis based on a 600-day Mars surface mission with a 6-person crew will be presented. Preliminary ESM sensitivity analysis identified that improving system energy conservation efficiency should be the focus of future research once the fundamental STAR process development has matured.