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Significant progress has been made at NASA Ames Research Center in the development of a heat melt compaction device called the Plastic Melt Waste Compactor (PMWC). The PMWC was designed to process wet and dry wastes generated on human space exploration missions. The wastes have a plastic content typically greater than twenty percent. The PMWC removes the water from the waste, reduces the volume, and encapsulates it by melting the plastic constituent of the waste. The PMWC is capable of large volume reductions. The final product is compacted waste disk that is easy to manage and requires minimal crew handling. This paper describes the results of tests conducted using the PMWC with a wet and dry waste composite that was representative of the waste types expected to be encountered on long duration human space exploration missions.

A microwave powered solid waste stabilization and water recovery prototype was delivered to Ames Research Center through an SBIR Phase II contract awarded to Umpqua Research Company. The system uses a container capable of holding 5.7 dm3 volume of waste. The microwave power can be varied to operate either at full power (130 W) or in a variable mode from 0% and 100%. Experiments were conducted with different types of wastes (wet cloth, simulated feces/diarrheal wastes, wet trash and brine) at different levels of moisture content and dried under varying microwave power supply. This paper presents the experimental data. The results provide valuable insight into the different operation modes under which the prototype can be used to recover water from the wastes in a space environment. Further investigations and testing of the prototype are recommended.

A Microwave Enhanced Freeze Drying Solid Waste (MEFDSW) processor was delivered to NASA-Ames Research Center by Umpqua Company having been funded through a Small Business Innovative Research Phase II program. The prototype hardware was tested for its performance characteristics and for its functionality with the primary focus being the removal of water from solid wastes. Water removal from wastes enables safe storage of wastes, prevents microbes from growing and propagating using the waste as a substrate and has potential for recovery and reuse of the water. Other objectives included measurements of the power usage and a preliminary estimate of the Equivalent System Mass (ESM) value. These values will be used for comparison with other candidate water removal technologies currently in development.

Since the mid 1980s, NASA has developed advanced waste management technologies that collect and process waste. These technologies include incineration, hydrothermal oxidation, pyrolysis, electrochemical oxidation, activated carbon production, brine dewatering, slurry bioreactor oxidation, composting, NOx control, compaction, and waste collection. Some of these technologies recover resources such as water, oxygen, nitrogen, carbon dioxide, carbon, fuels, and nutrients. Other technologies such as the Waste Collection System (WCS - the commode) collect waste for storage or processing. The need for waste processing varies greatly depending upon the mission scenario. This paper reviews the waste management technology development activities conducted by NASA since the mid 1980s and explores the drivers that determine the application of these technologies to future missions.

In February 2004 NASA released “The Vision for Space Exploration.” The goals outlined in this document include extending the human presence in the solar system, culminating in the exploration of Mars. A key requirement for this effort is to identify a safe and effective method to process waste. Methods currently under consideration include incineration, microbial oxidation, pyrolysis, drying, and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this work is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. Previously, TDA Research, Inc. demonstrated the potential of a low temperature dry oxidation process using ozone in a small laboratory reactor.

A Microwave Enhanced Solid Waste Freeze Drying Prototype system has been developed for the treatment of solid waste materials generated during extended manned space missions. The system recovers water initially contained within wastes and stabilizes the residue with respect to microbial growth. Dry waste may then be safely stored or passed on to the next waste treatment process. Operating under vacuum, microwave power provides the energy necessary for sublimation of ice contained within the waste. This water vapor is subsequently collected as relatively pure ice on a Peltier thermoelectric condenser as it travels en route to the vacuum pump. In addition to stabilization via dehydration, microwave enhanced Freeze Drying reduces the microbial population (∼90%) in the waste.

Waste management is a critical component of life support systems for manned space exploration. Human occupied spacecraft and extraterrestrial habitats must be able to effectively manage the waste generated throughout the entire mission duration. The requirements for waste systems may vary according to specific mission scenarios but all waste management operations must allow for the effective collection, containment, processing, and storage of unwanted materials. NASA's Crew Exploration Vehicle usually referred to as the CEV, will have limited volume for equipment and crew. Technologies that reduce waste storage volume free up valuable space for other equipment. Waste storage volume is a major driver for the Orion waste compactor design. Current efforts at NASA Ames Research Center involve the development of two different prototype compactors designed to minimize trash storage space.

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.

A Microwave Powered Solid Waste Stabilization and Water Recovery Prototype system has been developed for the treatment of solid waste materials generated during extended manned space missions. The system recovers water initially contained within wastes and stabilizes the residue with respect to microbial growth. Dry waste may then be safely stored or passed on to the next waste treatment process. Using microwave power, water present in the solid waste is selectively and rapidly heated. Liquid phase water flashes to steam and superheats. Hot water and steam formed in the interior of waste particles create an environment that is lethal to bacteria, yeasts, molds, and viruses. Steam contacts exposed surfaces and provides an effective thermal kill of microbes, in a manner similar to that of an autoclave. Volatilized water vapor is recovered by condensation.

Handling and processing human feces in space habitats is a major concern and needs to be addressed for the Crew Exploration Vehicle (CEV) as well as for future exploration activities. In order to ensure crew health and safety, feces should either be isolated in a dried form to prevent microbial activity, or be processed to yield a non-biohazardous product using a reliable technology. During laboratory testing of new feces processing technologies, use of “real” feces can impede progress due to practical issues such as safety and handling thereby limiting experimental investigations. The availability of a non-hazardous simulant or analogue of feces can overcome this limitation. Use of a simulant can speed up research and ensure a safe laboratory environment. At Ames Research Center, we have undertaken the task of developing human fecal simulants. In field investigations, human feces show wide variations in their chemical/physical composition.

This paper describes current work at NASA Ames Research Center on the development of compaction technologies for near and far term space missions. Current efforts involve the development of compactor concepts for lunar missions as outlined in the new Space Exploration Initiative and for far term space missions such as a lunar outpost or Mars exploration mission. The current efforts include the analysis and investigation of compactor design concepts for the Crew Exploration Vehicle and also the design and manufacture of a heat melt compactor for longer term missions.

Newly outlined missions in the Vision for U.S. Space Exploration include extended human habitation on Mars. During these missions, large amounts of waste materials will be generated in solid, liquid and gaseous form. Returning these wastes to Earth will be extremely costly, and increase the opportunity for back contamination. Therefore, it is advantageous to investigate the potential for wastes to remain on Mars after mission completion. Untreated, these wastes are a reservoir of live/dead organisms and molecules considered “biomarkers” (i.e., indicators of life). If released to the planetary surface, these materials can potentially interfere with exobiology studies, disrupt any existent martian ecology and pose human safety concerns. Waste Management (WM) systems must therefore be specifically designed to control release of problematic materials both during the active phase of the mission, and for any specified post-mission duration.

This paper describes current work at NASA Ames Research Center on the development of a heat melt compactor that can be used on both near term and far term missions. Preliminary tests have been performed to characterize the behavior of composite wastes that are representative of the types of wastes produced on current and previous space missions such as International Space Station, Space Shuttle, MIR and Skylab. Preliminary tests were conducted to characterize the volume reduction, bonding, encapsulation and plastic extrusion of the waste composite. The preliminary tests are designed to provide the data needed to design the first prototype Plastic Melt Waste Compactor.

This paper describes work that has begun at Ames Research Center on development of a heat melt compactor that can be used on near term and future missions. The heat melt compactor can handle wastes with a significant plastic composition and minimize crew interaction. The current solid waste management system employed on the International Space Station (ISS) consists of compaction, storage, and disposal. Wastes such as plastic food packaging and trash are compacted manually and wrapped in duct taped “footballs” by the astronauts. Much of the waste is simply loaded into the empty Russian Progress spacecraft that is used to bring supplies to ISS. The progress spacecraft and its contents are intentionally burned up in the earth's atmosphere during reentry. This manual method of trash management on ISS is a wasteful use of crew time and does not transition well to far term missions.

Equivalent System Mass (ESM) is used by the Advanced Life Support (ALS) community to quantify mission costs of technologies for space applications (Drysdale et al, 1999, Levri et al, 2000). Mass is used as a cost measure because the mass of an object determines propulsion (acceleration) cost (i.e. amount of fuel needed), and costs relating to propulsion dominate mission cost. Mission location drives mission cost because acceleration is typically required to initiate and complete a change in location. Total mission costs may be reduced by minimizing the mass of materials that must be propelled to each distinct location. In order to minimize fuel requirements for missions beyond low-Earth orbit (LEO), the hardware and astronauts may not all go to the same location. For example, on a Lunar or Mars mission, some of the hardware or astronauts may stay in orbit while the rest of the hardware and astronauts descend to the planetary surface.

NASA Ames Research Center and Lawrence Berkeley National lab have completed a three-year joint NRA research project on the use of waste biomass to make a gaseous contaminant removal system. The objective of the research was to produce activated carbon from life support wastes and to use the activated carbon to adsorb and remove incineration flue gas contaminants such as NOx. Inedible biomass waste from food production was the primary waste considered for conversion to activated carbon. Previous research at NASA Ames has demonstrated the adsorption of both NOx and SO2 on activated carbon made from biomass and the subsequent conversion of adsorbed NOx to nitrogen and SO2 to sulfur. This paper presents the results testing the whole process system consisting of making, using, and regenerating activated carbon with relevant feed from an actual incinerator. Factors regarding carbon preparation, adsorption and regeneration are addressed.

Incineration is a promising method for converting biomass and human waste into CO2 and H2O during extended planetary exploration. Unfortunately, it produces NOX and other pollutants. TDA Research has developed a safe and effective process to remove NOX from waste incinerator product gas streams. In our process, NO is catalytically oxidized to NO2, which is then removed with a wet scrubber. In a SBIR Phase II project, TDA designed and constructed a pilot scale system, which will be used with the incinerator at NASA Ames Research Center. In this paper, we present test results obtained with our system, which clearly demonstrate the effectiveness of this approach to NOX control.

Solid Waste Management (SWM) systems of current and previous space flight missions have employed relatively uncomplicated methods of waste collection, storage and return to Earth. NASA's long-term objectives, however, will likely include human-rated missions that are longer in both duration and distance, with little to no opportunity for re-supply. Such missions will likely exert increased demands upon all sub-systems, particularly the SWM system. In order to provide guidance to SWM Research and Technology Development (R&TD) efforts and overall system development, the establishment of appropriate SWM system requirements is necessary. Because future long duration missions are not yet fully defined, thorough mission-specific requirements have not yet been drafted.

In this paper we have developed a unique approach to providing the elements required for crop production in a steady-state condition, which is essential for Space habitats. The approach takes into consideration human elemental requirements and crop requirements for healthy growth and develops a method for the calculation of the rates of nutrient uptake for the different elements for different crops. The uptake rates can be used to calculate the rate of nutrient supply required in the hydroponic solution. This approach ensures that crops produced will not have excessive levels of elements that may be harmful to humans. It also provides an opportunity to optimize the processes of crop production and waste processing through highly controlled feed rates.

This paper presents the results from a joint research initiative between NASA Ames Research Center and Lawrence Berkeley National lab. The objective of the research is to produce activated carbon from life support wastes and to use the activated carbon to adsorb and chemically reduce the NOx and SO2 contained in incinerator flue gas. Inedible biomass waste from food production is the primary waste considered for conversion to activated carbon. Results to date show adsorption of both NOx and SO2 in activated carbon made from biomass. Conversion of adsorbed NOx to nitrogen has also been observed.