John A. Hogan

Biological removal of gaseous ammonia in biofilters : Space travel and earth-based applications

ABSTRACT Gaseous NH3 removal was studied in laboratory-scale biofilters (14-L reactor volume) containing perlite inoculated with a nitrifying enrichment culture. These biofilters received 6 L/min of airflow with inlet NH3 concentrations of 20 or 50 ppm, and removed more than 99.99% of the NH3 for the period of operation (101, 102 days). Comparison between an active reactor and an autoclaved control indicated that NH3 removal resulted from nitrification directly, as well as from enhanced absorption resulting from acidity produced by nitrification. Spatial distribution studies (20 ppm only) after 8 days of operation showed that nearly 95% of the NH3 could be accounted for in the lower 25% of the biofilter matrix, proximate to the port of entry. Periodic analysis of the biofilter material (20 and 50 ppm) showed accumulation of the nitrification product NO3 - early in the operation, but later both NO2 - and NO3 - accumulated. Additionally, the N-mass balance accountability dropped from near 100% early in the experiments to ~95 and 75% for the 20- and 50-ppm biofilters, respectively. A partial contributing factor to this drop in mass balance accountability was the production of NO and N2O, which were detected in the biofilter exhaust.

The Low-Power CO2 Removal and Compression System: Design Advances and Development Status

Active resource recovery from metabolic CO2 facilitates long-duration missions by decreasing cost and increasing self-sustainability. To provide this capability, theLow-Power CO2 Removal � (LPCOR) closed- loop air revitalization system is under development at NASA Ames Research Center. The LPCOR system is designed to perform the same CO2 removal function as the four-bed molecular sieve (4BMS) system currently employed on the International Space Station (ISS), with the additional integrated ability to purify and thermally compress CO2 to supply downstream CO2 recovery units. The LPCOR design goals include decreasing cabin air CO2 concentration up to 60% while yielding a 50% power savings when compared to current ISS levels. The LPCOR system increases power efficiency by replacing the desiccant (packed) beds of the 4BMS with a passive, Nafion ® hollow-fiber membrane bulk dryer and a state-of-the-art engineered structured sorbent device that requires only 25% of the thermal energy required by the 4BMS desiccant beds. CO2 removal, purification, and compression functions are performed in an integrated 2-Stage adsorption canister. CO2 is removed from the cabin air and partially compressed in Stage 1. The CO2 is concentrated in a smaller Stage 2, where thermal desorption is then used to further compress the CO2 for delivery to a reduction unit (e.g., a Sabatier reactor) for oxygen recovery. This paper presents the ongoing design considerations and development status of the LPCOR system, including overall design principles, characterization tests, airflow distribution modeling, and potential design strategies for current and future components.

Requirements Development Issues for Advanced Life Support Systems: Solid Waste Management

Long duration missions pose substantial new challenges for solid waste management in Advanced Life Support (ALS) systems. These possibly include storing large volumes of waste material in a safe manner, rendering wastes stable or sterilized for extended periods of time, and/or processing wastes for recovery of vital resources. This is further complicated because future missions remain ill-defined with respect to waste stream quantity, composition and generation schedule. Without definitive knowledge of this information, development of requirements is hampered. Additionally, even if waste streams were well characterized, other operational and processing needs require clarification (e.g. resource recovery requirements, planetary protection constraints). Therefore, the development of solid waste management (SWM) subsystem requirements for long duration space missions is an inherently uncertain, complex and iterative process. The intent of this paper is to address some of the difficulties in writing requirements for missions that are not completely defined. This paper discusses an approach and motivation for ALS SWM requirements development, the characteristics of effective requirements, and the presence of those characteristics in requirements that are developed for uncertain missions. Associated drivers for life support system technological capability are also presented. A general means of requirements forecasting is discussed, including successive modification of requirements and the need to consider requirements integration among subsystems.

Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

Results Summary of the Life Support and Habitation and Planetary Protection Workshop

Summary of: Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface. NRC Committee on Precursor Measurements Necessary to Support Human Operation on the Surface of Mars, National Academy Press, Washington DC, 2002 • Summary of: Planetary Protection Issues in the Human Exploration of Mars (Summarized) Race, M.S., M.E. Criswell, and J.D. Rummel, 2003. (Paper no. 2003-01-2523. International Conference on Environmental Systems (ICES), Vancouver, B.C. July 2003 ) • Summary of: Influence of Planetary Protection Guidelines on Waste Management Operations. J.A. Hogan, J.W. Fisher, J.A. Levri, M.S. Race, K. Wignarajah, P. Stabekis. International Conference on Environmental Systems (ICES), Rome, Italy. July 2005, Paper no. 2005-01-3097. Additionally, relevant programmatic websites were given to allow participants to seek additional information. These website are listed below: Life Support and Habitation: http://lsh.jsc.nasa.gov/Life Support and Habitation Overview Presentation: http://www.dsls.usra.edu/meetings/bio2005/pdf/Walzpresentation.pdfPlanetary Protection: http://planetaryprotection.nasa.gov/pp/documents/index.htmAdvanced Life Support: http://advlifesupport.jsc.nasa.gov/ 9

Architecture and Functionality of the Advanced Life Support On-Line Project Information System

An ongoing effort is underway at NASA Ames Research Center (ARC) to develop an On-line Project Information System (OPIS) for the Advanced Life Support (ALS) Program. The objective of this three-year project is to develop, test, revise and deploy OPIS to enhance the quality of decision-making metrics and attainment of Program goals through improved knowledge sharing. OPIS will centrally locate detailed project information solicited from investigators on an annual basis and make it readily accessible by the ALS Community via a Web-accessible interface. The data will be stored in an object-oriented relational database (created in MySQL) located on a secure server at NASA ARC. OPE will simultaneously serve several functions, including being an research and technology development (R&TD) status information hub that can potentially serve as the primary annual reporting mechanism for ALS-funded projects. Using OPIS, ALS managers and element leads will be able to carry out informed R&TD investment decisions, and allow analysts to perform accurate systems evaluations. Additionally, the range and specificity of information solicited will serve to educate technology developers of programmatic needs. OPIS will collect comprehensive information from all ALS projects as well as highly detailed information specific to technology development in each ALS area (Waste, Water, Air, Biomass, Food, Thermal, Controls and Systems Analysis). Because the scope of needed information can vary dramatically between areas, element-specific technology information is being compiled with the aid of multiple specialized working groups. This paper presents the current development status in terms of the architecture and functionality of OPIS. Possible implementation approaches for OPIS are also discussed.

An On-Line Technology Information System (OTIS) for Advanced Life Support

OTIS is an on-line communication platform designed for smooth flow of technology information between advanced life support (ALS) technology developers, researchers, system analysts, and managers. With pathways for efficient transfer of information, several improvements in the ALS Program will result. With OTIS, it will be possible to provide programmatic information for technology developers and researchers, technical information for analysts, and managerial decision support. OTIS is a platform that enables the effective research, development, and delivery of complex systems for life support. An electronic data collection form has been developed for the solid waste element, drafted by the Solid Waste Working Group. Forms for other elements (air revitalization, water recovery, food processing, biomass production and thermal control) will also be developed, based on lessons learned from the development of the solid waste form. All forms will be developed by consultation with other working groups, comprised of experts in the area of interest. Forms will be converted to an on-line data collection interface that technology developers will use to transfer information into OTIS. Funded technology developers will log in to OTIS annually to complete the element- specific forms for their technology. The type and amount of information requested expands as the technology readiness level (TRL) increases. The completed forms will feed into a regularly updated and maintained database that will store technology information and allow for database searching. To ensure confidentiality of proprietary information, security permissions will be customized for each user. Principal investigators of a project will be able to designate certain data as proprietary and only technical monitors of a task, ALS Management, and the principal investigator will have the ability to view this information. The typical OTIS user will be able to read all non-proprietary information about all projects.Interaction with the database will occur over encrypted connections, and data will be stored on the server in an encrypted form. Implementation of OTIS will initiate a community-accessible repository of technology development information. With OTIS, ALS element leads and managers will be able to carry out informed technology selection for programmatic decisions. OTIS will also allow analysts to make accurate evaluations of technology options. Additionally, the range and specificity of information solicited will help educate technology developers of program needs. With augmentation, OTIS reporting is capable of replacing the current fiscal year-end reporting process. Overall, the system will enable more informed R&TD decisions and more rapid attainment of ALS Program goals.