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The effects of volume-reduction via compaction (VR-C) on microbial loads and microbially-produced noxious odors during post-treatment storage were investigated. The Crew Exploration Vehicle (CEV) / Orion simulated food trash compartment wastes (FTCW) consisted of 80% food trash with packaging and 20% wipes. Compaction was compared with a non-compacted control and will provide a baseline for comparison with other treatment technologies. The first study was a timecourse with post-treatment storage durations of 1, 2, 4, and 6 weeks. Key response variables were: O2 consumption and CO2 production from waste biodegradation and microbiological assays consisting of total counts and culturable counts of (a) aerobic and anaerobic bacteria, (b) aerobic and anaerobic spore-forming bacteria, (c) specific bacteria including Pseudomonas aeruginosa, Burkholderia cepacia, and Staphylococcus aureus counts, and (d) molds at run termination.

Carbosieve SIII was used to filter dichloromethane (DCM) from a simulated spacecraft gas stream. This adsorbent was tested as a possible commercial-off-the-shelf (COTS) filtration solution to controlling spacecraft air quality. DCM is a halocarbon commonly used in manufacturing for cleaning and degreasing and is a typical component of equipment offgassing in spacecraft. The performance of the filter was measured in dry and humid atmospheres. A known concentration of DCM was passed through the adsorbent at a known flow rate. The adsorbent removed dichloromethane until it reached the breakthrough volume. Carbosieve SIII exposed to dry atmospheric conditions adsorbed more DCM than when exposed to humid air. Carbosieve SIII is a useful thermally regenerated adsorbent for filtering DCM from spacecraft cabin air. However, in humid environments the gas passes through the filter sooner due to co-adsorption of additional water vapor from the atmosphere.

This work describes the microbiological assessment and materials compatibility of a silver-based biocide as an alternative to iodine for the Crew Exploration Vehicle (CEV) and future spacecraft potable water systems. In addition to physical and operational anti-microbial counter-measures, the prevention of microbial growth, biofilm formation, and microbiologically induced corrosion in water distribution and storage systems requires maintenance of a biologically-effective, residual biocide concentration in solution and on the wetted surfaces of the system. Because of the potential for biocide depletion in water distribution systems and the development of acquired biocide resistance within microbial populations, even sterile water with residual biocide may, over time, support the growth and/or proliferation of bacteria that pose a risk to crew health and environmental systems.

A lab-scale testbed for screening and characterizing the chemical specificity of commercial “off-the-shelf” (COTS) polymer adsorbents was built and tested. COTS polymer adsorbents are suitable candidates for future trace contaminant (TC) control technologies. Regenerable adsorbents could reduce overall TC control system mass and volume by minimizing the amounts of consumables to be resupplied and stored. However, the chemical specificity of these COTS adsorbents for non-methane volatile organic compounds (NMVOCs) (e.g., methanol, ethanol, dichloromethane, acetone, etc) commonly found in spacecraft is unknown. Furthermore, the effect of humidity on their filtering capacity is not well characterized. The testbed, composed of a humidifier, an incubator, and a gas generator, delivers NMVOC gas streams to conditioned sorbent tubes.

The KSC Breadboard Scale Aerobic Bioreactor (B-SAB) was used to bioprocess inedible wheat crop residues to provide recycled nutrients to support crop growth in the JSC Variable Pressure Growth Chamber (VPGC) as part of the 91 day JSC-Lunar/Mars Life Support Test Project Phase III. To meet the wheat nutrient demand at JSC, the KSCB-SAB was operated at both a higher loading rate (35 gdw L-1 compared with 20 gdw L-1) and at a slower retention time (21 days compared with 8 days) than we had used in previous bioreactor (continuous stirred tank reactor - CSTR) studies. The bioreactor operated for 19 weeks-8 weeks startup and steady state stabilization then 11 weeks of operation with the broth harvested weekly. Filtered broth was amended with nutrients and transported to JSC for integration into the VPGC wheat growth component of L/MLSTP Phase III. Biodegradation of JSC wheat residues was a constant 45% during steady state bioreactor operation, and similar to previous B-SAB runs.

Understanding the effects of dynamic thermal and vacuum regeneration on VOC desorption kinetics is needed for the development of regenerable trace contaminant control air revitalization systems. The effects of temperature and vacuum quality on the desorption kinetics of ethanol from Carbosieve SIII were examined using 1 hour regeneration cycles. The effect of vacuum quality on ethanol desorption was studied by exposing adsorption tubes loaded with ethanol to low pressures (1.0, 0.5, 0.3, and 0.12 atm) at various thermal regeneration temperatures (160, 100, 70, and 25 °C). At 1 atm of pressure, ethanol removal was found to increase from 2% at 25 °C, to 25% at 70 °C, to 55% at 100 °C, and to 77% at 160 °C. Decreasing the atmospheric pressure from 1 to 0.1 atm for 1 hr did not significantly enhance Carbosieve SIII regeneration at ambient temperatures (25 °C). However, heating the adsorbent at low pressures enhanced its regeneration.

With the installation of the Water Recovery System (WRS) during mission STS-126 in 2008, the International Space Station (ISS) added the capability to recover clean water for reuse from crewmember urine and atmospheric humidity condensate, including EVA (Extravehicular Activity) wastes. The ability to collect, store and process these waste streams is required to increase potable water recovery and support the ISS crew augmentation planned for 2009. During ground testing of the Urine Processing Assembly (UPA), one of two primary component subsystems that comprise the WRS, significant fouling was repeatedly observed in stored urine pretreated with 0.56% of chromium trioxide and sulfuric acid. During initial observation, presumptive microbiological growth clogged and damaged flight-rated hardware under test as part of a risk-mitigation Flight Experiment (FE).

This report describes ground testing of a commercial-off-the-shelf (COTS) water treatment device for contingency recovery of potable liquid from ersatz human urine to support spaceflight testing. The Forward Osmosis Bag (FOB) is a portable, passive water treatment device utilizing osmotic potential to move water across a layered, ultra-filtration membrane to remove pathogens and reject chemical contaminants. The FOB is capable of rejecting ≥90% of the salts, ≥85% of the Total Oxidizable Carbon (TOC), ≥95% of the Total Nitrogen (TN), and ≥93% of Urea-Nitrogen (BUN) in the ersatz urine while completely removing a mixed bacterial population of >108 cells per milliliter.

This report describes proof-of-concept testing of a commercial-off-the-shelf deep ultraviolet LED for future application as a point-of-use or residual disinfection device for spacecraft potable water systems. The electro-optical performance and disinfection efficacy of a 0.5 mW 265nm UV-C LED (UVTOP, Sensor Electronic Technology, Inc., Columbia, SC) was measured in both static and flow environments against five challenge microorganisms inoculated into potable water at an initial concentration ≥ 108 cells per milliliter. The germicidal irradiation from a single UV-C LED array was sufficient to effect > 4-log kill (> 99.99%) of the challenge bacterial population in < 60 minutes contact time.

A sub-scale testbed for characterizing the dynamic performance of regenerable adsorbents for filtering trace contaminants (TCs) from cabin atmospheres was built and tested. Regenerable adsorbents employed in pressure-swing adsorption (PSA) systems operate in a dynamic environment, where they undergo repeated loading / regeneration cycles. Adsorbents have a given chemical specificity for non-methane TCs depending on their composition, and on the humidity and temperature at which they operate. However, their ability to filter TCs is also affected by contact time, cycle time, regeneration vacuum quality and thermal conditioning.

Microorganisms will be an integral part of biologically based waste processing systems used for water purification or nutrient recycling on space flights. Establishment of these systems with a defined group of microorganisms will provide a standardized means for conferring specific properties to the system. The purpose of this study was to develop microbial inocula (a defined, constructed community and an undefined community) for initiation of plant-based graywater waste processing systems. To this end, small-subunit 16S rDNA sequence analysis was used to describe the population composition of microbial communities from a plant-based graywater waste treatment system and from an industrial wastewater treatment plant (WWTP). The clonal library of organisms from the graywater-degrading rhizosphere community suggested that members of the Cytophagales and Proteobacteria phylogenetic groups dominated. The clonal library of organisms from industrial WWTP was taxonomically more diverse.

The PESTO (Photosynthetic Experiment System Testing and Operation) experiment flew in the Biomass Production System (BPS) to International Space Station (ISS) on STS-110 (Atlantis) April 8, 2002, and returned on STS-111 (Endeavour) June 19, 2002, after 73 days in space. The ground control was conducted on a two-week delay at Kennedy Space Center in a BPS unit under environmental conditions comparable to ISS. Wheat (Triticum aestivum cv Apogee) and Brassica rapa cv Astroplant were independently grown in root modules for multiple grow-outs. On-orbit harvests, root modules exchanges and primings, seeds imbibitions, and gas and water samplings occurred at periodic intervals; all were replicated in ground controls. Many operations required crew handling and open access to individual chambers, allowing the exchange of microorganisms between the crew environment and the BPS modules.

Spacecraft cabin air quality is influenced by a variety of factors. Beyond normal equipment offgassing and crew metabolic loads, the vehicle's operational configuration contributes significantly to overall air quality. Leaks from system equipment and payload facilities, operational status of the atmospheric scrubbing systems, and the introduction of new equipment and modules to the vehicle all influence air quality. The dynamics associated with changes in the International Space Station's (ISS ) configuration since the launch of the U.S. Segment's laboratory module, Destiny, is summarized. Key classes of trace chemical contaminants that are important to crew health and equipment performance are emphasized. The temporary effects associated with attaching each multi-purpose logistics module (MPLM) to the ISS and influence of in-flight air quality on the post-flight ground processing of the MPLM are explored.

Different options have been examined for providing minerals to plants for bioregeneration. The baseline option is to ship the minerals. The equivalent system mass of two different bioreactor systems for recycling a portion of these minerals, a fixed-film bioreactor and a stirred-tank reactor are calculated. Either option could reduce the ESM for providing these minerals for a 15-year mission to Mars, with 50% food closure.

A continuous leaching device was designed to extract inorganic nutrients from ALS solid wastes for recycling back to hydroponic plant growth systems. The system consists of a conveyor that carries the waste under a water spray. The leacher was used to extract nutrients from hydroponic rice crop residues. The highly aerated and nutrient-rich recirculation liquid supports microbial growth on all surfaces, which leads to biofouling that causes maintenance difficulties. However, it may be better than the standard leaching protocol, as it produces leachate with significantly reduced BOD. This would make it possible to use the leachate from this reactor in hydroponic plant systems without further processing.

Volatile organic compounds (VOCs) are important indoor air pollutants, particularly in spaces lacking adequate ventilation and containing off gassing materials. The problem is particularly acute in closed environments, such as spacecraft. The best solution to controlling VOC accumulation in closed environments is eliminating the offending chemicals from the spacecraft design. However, when this is not possible, removal of VOCs from spacecraft air is necessary. Two species of fungi, Paecilomyces lilacinus and Fusarium verticillioides, were tested for the ability to remove tert-butanol from air. The fungi were grown on PCA+C agar and placed into jars with high atmospheric concentrations of t-butanol. The concentration of t-butanol was monitored in the containers for one week. The t-butanol consumption rates were estimated after adjusting for leakage. Leak rates ranged from 0.0003 to 0.0027 h-1.

The National Aeronautics and Space Administration (NASA) intends to continue the human exploration of outer space. Long duration missions will require the development of reliable regenerative life support processes. The intent of this paper is to define the Kennedy Space Center Controlled Ecological Life Support System (CELSS) research plan for the development and testing of three candidate biological processors for a hybrid biological and physical-chemical waste recycling system. The system would be capable of reclaiming from inedible plant biomass, human metabolic waste, and gray water those components needed for plant growth (carbon dioxide, water, and inorganic salts), while eliminating noxious compounds and maximizing system closure. We will colaborate with AMES Research Center (ARC), Johnson Space Center (JSC), and academia, to design a functional biological-based waste processing system that could be integrated with the planned Human Rated Test Facility (HRTF) at JSC.

A set of contained environment chambers have been designed to study the effects of Volatile Organic Compounds (VOCs) on plant growth and development. The Volatile Organic Compound Analysis (VOCA) system consists of six Lexan chambers, each with independent VOC monitoring and control capacities. The VOC exposure chambers are located within a larger controlled environment chamber (CEC) which provides a common air temperature, photoperiod, and light control. Relative humidity, CO2 concentration, and VOC concentration of the atmosphere are independently controlled in each VOCA exposure chambers. CO2, air temperature, relative humidity and PPF are continuously monitored with software developed using IOControl™ and IODisplay™.

The candidate crops that have been considered by NASA for providing moderate quantities of supplemental food for crew's consumption during near term or long duration missions include minimally processed “salad” species. Lettuce (cv. Flandria), radish (cv. Cherry Bomb II) and green onion (cv. Kinka) plants were grown under cool-white fluorescent (CWF) lamps with light intensities of 8.6, 17.2, or 25.8 mol m−2 d−1, at air temperatures of 25 and 28 °C, 50% relative humidity, and 1200 µmol mol−1 CO2. Following 35 days growth, final edible mass yields were recorded. All three species grown at 25 °C showed an increase in edible fresh mass and growth rates as light intensity increased. When grown at 28 °C however, the edible fresh mass and crop growth rate of radish, lettuce and onion was significantly reduced at all light intensities when compared to yields at 25 °C. Overall, results indicated that all three crops were sensitive to changes in light intensity and temperature.

The chemical specificity of several adsorbents, capable of being recycled by thermal desorption, was determined using volatile organic compounds (VOCs) found in ISS cabin air. These VOC adsorbents will be used to design a reusable filter to control ethylene in plant growth chambers and other STS/ISS biological payloads. A reusable filter to remove plant-produced ethylene from plant growth chambers could help minimize the mass and power use of plant flight hardware. Spaceflight-rated plant growth chambers employ either passive or active catalytic scrubbers for maintaining acceptable levels of VOCs. Passive systems require consumables, while active systems require power and their performance can be degraded in high humidity environments. Each adsorbent was loaded with known amounts of VOCs at a known flow rate. The filtering capacity and chemical specificity of each compound was determined from measurements pre- and post-filter VOC concentration.