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Water recovery is essential for long-duration space exploration transit and outpost missions. Primary stage wastewater recovery systems partially satisfy this need, and generate concentrated wastewater brines that are unusable without further processing. The Enhanced Brine Dewatering System (EBDS) is being developed to allow nearly complete recovery of water from Lunar Outpost wastewater brines. This paper describes the operation of the EBDS and discusses the development and testing of the major functional materials, components, and subsystems, including the wastewater brine ersatz formulations that are used in subsystem testing. The assembly progress of the EBDS full system prototype is also discussed, as well as plans for testing the prototype hardware.

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter.

Early development of wastewater and brine processing equipment must rely upon ersatz formulations because authentic urine and hygiene water are variable in composition, difficult to acquire in quantity, and have limited storage life. Previous wastewater ersatz formulations (e.g. Verostko et al, 2004) were designed for chemical fidelity, to match the elemental ratios and VOC profile of defined blends of wastewater components. This paper presents an alternative spreadsheet approach to brine and wastewater ersatz formulation by combining “building block” recipes in user-selected ratios and accounting for compositional shifts upon evaporation.

To investigate the flammability of human hair, a series of normal and microgravity flame spread tests over human hair were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows (∼20 cm/s). The tunnel atmosphere pressure and oxygen concentration was varied over the range of anticipated exploration atmospheres (21–34% O2 in N2, 8–14.7 psia). While hair is marginally flammable in air, spreading upward but not downward, it burns extremely well at or above 30% O2 in any direction or g-level. The spread is characterized by a quick spread over the surface ‘nap’ or ‘frizz’, followed by continued bulk burning. Two hair ‘styles’ were tested — short hair and long hair — and style does not seem to affect initial nap spread significantly. Opposed and concurrent nap spread rates are similar in 0g under comparable conditions. Oxygen concentration has a strong effect on flame spread rates.

In order to support effective recycling of resources in a bioregenerative life support system (BLSS), the processing of inedible agricultural wastes into edible food products must be included. The process of converting agricultural waste into usable food resources is called secondary food production. Secondary food production offers a way to reclaim part of the energy and nutrients already sunk in inedible biomass, thus increasing the efficiency of the BLSS and crop harvest index. However, multi-step processes and lower yields and acceptability have made some secondary food production processes in the past problematic and costly. This paper presents preliminary process descriptions for secondary food products which are likely to be cost effective and well accepted: sugar syrup prepared from biomass hydrolysate, single cell oil produced from biomass hydrolysate, and Pleurotus mushroom fruit bodies grown on recalcitrant biomass and unused substrate.

A prototype packed bed convective dryer has been studied for use in an energy-efficient closed air-loop heat-pump drying system for astronaut cabin waste. This paper presents a transient continuum model for the heat and mass transfer between the air and wet ersatz trash in the cylindrical drying vessel. The model is based on conservation equations for energy and moisture applied to the air and solid phases and its formulation includes the unique waste characteristic of having both dry and wet solids. It incorporates heat and mass transfer coefficients for the system measured on an ersatz trash in the dryer vessel, and experimentally determined moisture sorption equilibrium relationship for the wet material. The resulting system of differential equations is solved by the finite-volume method as implemented by the commercial software COMSOL. The validated model will be used in the optimization of the entire closed-loop system consisting of dryer, condenser, and heat-recovery modules.

Brine dewatering by evaporation on porous media, and collection of wastewater evaporation condensates rich in organic carbon, both provide favorable environments for microbial growth, such as mold overgrowth of rayon wicks in the AES brine evaporation system, and bacterial biofilms on condensate-wetted surfaces. The mold growth reported on AES wicks by Campbell et al. (2003) has been identified by microscopic and molecular techniques as chiefly Chaetomium spp, most likely C. globosum, with minor occurrence of Penicillium, and other fungal species. Bacteria from the genus Bacillus was also isolated. A stable bacterial consortium dominated by three species was recovered from initially-sterile glass surfaces wetted with sterile Biological Water Processor Effluent Ersatz (Verostko et al., 2004) and exposed to humidified air over a period of one week. The species were identified as Enterobacter aerogenes, Microbacterium foliorum and Pseudomonas putida by 16S rDNA sequencing.

Wet cabin trash, including food residues, moist hygiene wipes and wet paper towels, poses two problems on long term space missions: first, the generation of odors and potential health hazards by microbial action (spoilage); second, the diversion of water from the available recovery loops. We have developed an energy-efficient closed air-loop heat-pump dryer to remove moisture from the wet material. Circulation of hot air can pasteurize the trash in the original bag without water recovery. In drying mode, a gravity-independent Porous Membrane Condensing Heat Exchanger (PMCHX) traps condensate to be passed to the water recovery system. The DRYER system is suitable for stabilization of wet cabin waste in an advanced life support system, and may be adapted to drying of crew laundry and water recovery from water-reprocessing brines.

Drying is an important process, ubiquitous on earth, and in space applications it is an unavoidable aspect of advanced life support technology. We analyze several solid and liquid waste treatment processes that involve drying as a primary operation and consider factors such as energy use, volume, mass, crew time upstream relief and downstream burden. The entry points of resources such as electrical energy, thermal energy, mass influent and effluent and crew time are discussed in the context of a common drying schematic, compared using generalized flow diagrams, and a table is provided to grasp the relative magnitudes.

The crew diet in a bioregenerative lifesupport system will be a combination of foods grown and processed in’situ with resupplied prepackaged foods and ingredients. The ideal diet should be palatable, nutritionally adequate, varied and low in cost. This diet can be obtained by adopting an optimization strategy combining panel acceptance data, nutritional analyses and mission specific ESM (equivalent system mass) cost estimates for a large selection of foods and ingredients. A linear programming routine selects the lowest cost diet from the foods surveyed, subject to constraints on nutrient content, food acceptability, and variety. The rigor of these constraints is a key factor in determining the cost of the diet (s) they define. By varying individual constraints over several optimizations, we can estimate sensitivity of overall costs to a particular nutrient, or even an intangible quality such as acceptability, while controlling other aspects of the diet.

A three phase catalytic mathematical model was developed for analysis and optimization of the volatile reactor assembly (VRA) used on International Space Station (ISS) Water Processor. The Langmuir-Hinshelwood Hougen-Watson (L-H) expression was used to describe the surface reaction rate. Small column experiments were used to determine the L-H rate parameters. The test components used in the experiments were acetic acid, acetone, ethanol, 1-propanol, 2-propanol and propionic acid. These compounds are the most prevalent ones found in the influent to the VRA reactor. The VRA model was able to predict performance of small column data and experimental data from the VRA flight experiment.

A bioregenerative diet is characterized by a high proportion of foods produced on site. The production and processing of foods into either ingredients or recipes entails certain labor requirements. Ideally these labor requirements should be estimated with a high degree of accuracy. Crew time is at premium and any amount of time spent on food preparation and processing is time not spent in conducting research and any other activities devised to improve the quality of life of the astronauts. Moreover, a wide variety of tasks are involved in the food preparation of a bioregenerative diet and the labor times of these tasks do not scale or increase in uniform fashion. Predicting food preparation labor requirements for varying crew sizes will require task specific models and data. Videotape analysis is a work measurement tool used in the manufacturing industry.

Future lunar missions will utilize a Lunar DC microgrid (LDCMG) to construct the infrastructure for distributing, storing, and utilizing electrical energy. The LDCMG’s energy management, of which energy storage systems (ESS) are crucial components, will be essential to the success of the missions. Standard system design currently employs a rule-of-thumb approach in which design methodologies rely on heuristics that may only evaluate local power balancing requirements. The Hamiltonian surface shaping and power flow control (HSSPFC) method can also be utilized to analyze and design the lunar LDCMG power distribution network and ESS. In this research, the HSSPFC method will be utilized to determine the ideal energy storage requirements for ESS and the optimally distributed control architecture.