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A workshop entitled the “Life Support & Habitation and Planetary Protection Workshop” was held in Houston, TX in April, 2005. The main objective of the workshop was to initiate communication, understanding, and a working relationship between the Life Support and Habitation1 (LSH) and Planetary Protection (PP) communities regarding the effect of the implementation of Mars human exploration PP policies on the Advanced Life Support2 (ALS), Advanced Extravehicular Activity (AEVA), and Advanced Environmental Monitoring and Control (AEMC) programs. This paper presents an overall summary of the workshop that includes workshop organization, objectives, starting assumptions, findings and recommendations. Specific result topics include the identification of knowledge and technology gaps, research and technology development (R&TD) needs, potential forward and back contaminants and pathways, mitigation alternatives, and PP requirements definition needs.

The use of air treatment biofilters for the control of trace air contaminants in advanced life support (ALS) systems is currently being investigated by the Waste Processing and Resource Recovery team of the New Jersey - NSCORT (NASA Specialized Center of Research and Training). Ammonia (NH3) was selected as a model compound because it presents special challenges to the sustained operation of a biofilter; additionally, ammonia' is a contaminant of concern to ALS. The special challenges that NH3 removal presents to biofilter operation are due to (dynamic changes in the biodegradation environment which result from the accumulation of ammonia and its metabolic (biotransformation) products. This accumulation degrades the quality of the environment eventually limiting and eliminating the desired biological activity. This paper contains inform&ion on the development of a mathematical model for a nitrifying biofilter.

Distant and/or long-term missions, particularly Mars and lunar bases, will require a high degree of regenerative systems utilization. Bio-regenerative systems inherently lend themselves to integrative application, and can serve multiple processing functions in Advanced Life Support (ALS) systems. Striving for maximal use of bio-regenerative systems can reveal possibilities and relationships difficult to conceptualize within the context of a “unit process” methodology common to physico-chemical (P/C) systems. The required regenerative functions of biomass production and solid, liquid, and air processing are discussed, and a potential integrated ALS system scenario including “soil'based” plant production is developed to illustrate potential ramifications of biological (and P/C) system integration.

The use of biofilters for the control of air contaminants in Advanced Life Support (ALS) systems is currently being investigated by the Waste Processing and Resource Recovery research team of the New Jersey - NSCORT (NASA Specialized Center of Research and Training). Ammonia (NH3) was selected as a test air contaminant as it presents special challenges to the sustained operation of a biofilter. Ammonia loading to the ALS atmosphere will likely be from waste treatment (biological treatment of human, plant and food wastes) and food processing operations. This NH3 has the potential of causing adverse effects on plant growth and humans.

A current study is investigating the feasibility of using air treatment biofilters to remove ethylene from atmospheres of Advanced Life Support (ALS) systems for spacecraft or planetary habitat environments. Ethylene was selected as the contaminant because: 1) it partitions poorly in water, thus challenging the limits of biofilter performance; and 2) it is a plant growth regulator that can adversely affect plant growth even at concentrations as low as 40 parts per billion (ppb). Thus control of ethylene in a biomass production chamber (BPC) is of direct concern. In laboratory scale studies ethylene was removed from air to below a target level of 20 ppb, with 4 ppb being the lowest exit concentration observed. This performance (<20 ppb) was observed for 12 days, with exit concentrations gradually increasing to 70 - 100 ppb by day 55. The decreased level of performance was apparently due to nutrient (nitrogen) limitation.

Biological treatment technologies used in removing air pollutants are reviewed from the perspective of an Advanced Life Support System (ALSS). These are based on the capability of microbial communities to biodegrade complex and variable mixtures of organic and inorganic compounds, typically to innocuous end products. The technologies considered are biofilters, biotrickling filters and bioscrubbers, with emphasis on biofilters. Theoretical design aspects are outlined. Different bed media (matrices) are described. A list of compounds treated successfully, solely or in complex mixtures, is provided. A brief summary of our current research on the removal of ethylene and ammonia (model compounds) through biofiltration is included.