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At least 109 records · Page 6

Microbial Characterization Space Solid Wastes Treated with a Heat Melt Compactor

The on going purpose of the project efforts was to characterize and determine the fate of microorganisms in space-generated solid wastes before and after processing by candidate solid waste processing. For FY 11, the candidate technology that was assessed was the Heat Melt Compactor (HMC). The scope included five HMC. product disks produced at ARC from either simulated space-generated trash or from actual space trash, Volume F compartment wet waste, returned on STS 130. This project used conventional microbiological methods to detect and enumerate microorganisms in heat melt compaction (HMC) product disks as well as surface swab samples of the HMC hardware before and after operation. In addition, biological indicators were added to the STS trash prior to compaction in order to determine if these spore-forming bacteria could survive the HMC processing conditions, i.e., high temperature (160 C) over a long duration (3 hrs). To ensure that surface dwelling microbes did not contaminate HMC product disk interiors, the disk surfaces were sanitized with 70% alcohol. Microbiological assays were run before and after sanitization and found that sanitization greatly reduced the number of identified isolates but did not totally eliminate them. To characterize the interior of the disks, ten 1.25 cm diameter core samples were aseptically obtained for each disk. These were run through the microbial characterization analyses. Low counts of bacteria, on the order of 5 to 50 per core, were found, indicating that the HMC operating conditions might not be sufficient for waste sterilization. However, the direct counts were 6 to 8 orders of magnitude greater, indicating that the vast majority of microbes present in the wastes were dead or non-cultivable. An additional indication that the HMC was sterilizing the wastes was the results from the added commercial spore test strips to the wastes prior to HMC operation. Nearly all could be recovered from the HMC disks post-operation and all were showed negative growth when run through the manufacturer's protocol, meaning that the 106 or so spores impregnated into the strips were dead. Control test strips, i.e., not exposed to the HMC conditions were all strongly positive. One area of concern is that the identities of isolates from the cultivable counts included several human pathogens, namely Staphylococcus aureus. The project reported here provides microbial characterization support to the Waste Management Systems element of the Life Support and Habitation Systems program.

Strayer, Richard F.↗

Mission Benefits Analysis of Logistics Reduction Technologies

Future space exploration missions will need to use less logistical supplies if humans are to live for longer periods away from our home planet. Anything that can be done to reduce initial mass and volume of supplies or reuse or recycle items that have been launched will be very valuable. Reuse and recycling also reduce the trash burden and associated nuisances, such as smell, but require good systems engineering and operations integration to reap the greatest benefits. A systems analysis was conducted to quantify the mass and volume savings of four different technologies currently under development by NASA fs Advanced Exploration Systems (AES) Logistics Reduction and Repurposing project. Advanced clothing systems lead to savings by direct mass reduction and increased wear duration. Reuse of logistical items, such as packaging, for a second purpose allows fewer items to be launched. A device known as a heat melt compactor drastically reduces the volume of trash, recovers water and produces a stable tile that can be used instead of launching additional radiation protection. The fourth technology, called trash ]to ]supply ]gas, can benefit a mission by supplying fuel such as methane to the propulsion system. This systems engineering work will help improve logistics planning and overall mission architectures by determining the most effective use, and reuse, of all resources.

Ewert, Michael K.↗

Mission Benefits Analysis of Logistics Reduction Technologies

Future space exploration missions will need to use less logistical supplies if humans are to live for longer periods away from our home planet. Anything that can be done to reduce initial mass and volume of supplies or reuse or recycle items that have been launched will be very valuable. Reuse and recycling also reduce the trash burden and associated nuisances, such as smell, but require good systems engineering and operations integration to reap the greatest benefits. A systems analysis was conducted to quantify the mass and volume savings of four different technologies currently under development by NASA s Advanced Exploration Systems (AES) Logistics Reduction and Repurposing project. Advanced clothing systems lead to savings by direct mass reduction and increased wear duration. Reuse of logistical items, such as packaging, for a second purpose allows fewer items to be launched. A device known as a heat melt compactor drastically reduces the volume of trash, recovers water and produces a stable tile that can be used instead of launching additional radiation protection. The fourth technology, called trash-to-gas, can benefit a mission by supplying fuel such as methane to the propulsion system. This systems engineering work will help improve logistics planning and overall mission architectures by determining the most effective use, and reuse, of all resources.

Ewert, Michael K.↗

Heat Melt Compaction as an Effective Treatment for Eliminating Microorganisms from Solid Waste

One of the technologies being tested at NASA Ames Research Center (ARC) for the Advance Exploration Systems program and as part of the logistics and repurposing project is heat melt compaction (HMC) of solid waste. Reduces volume, removes water and renders a biologically stable and safe product. The HMC compacts and reduces the trash volume as much as 90o/o greater than the current manual compaction used by the crew.The project has three primary goals or tasks. 1. Microbiological analysis of HMC hardware surfaces before and after operation. 2. Microbiological and physical characterizations of heat melt tiles made from trash at different processing times and temperatures. 3. Long term storage and stability of HMC trash tiles or "Do the bugs grow back?"

Hummerick, Mary P.↗

Logistics Reduction and Repurposing Technology for Long Duration Space Missions

One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items, and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by one manifest item having two purposes rather than two manifest items each having only one purpose. This paper provides the status of each of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACSs) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags for potential reuse on-orbit. Autonomous logistics management is using radio frequency identification (RFID) to track items and thus reduce crew time for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. A heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is under way. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology.

Broyan, James Lee, Jr.↗

Odor Control Test Plan of the Urine Containment Bag (UCB) for Orion Utilization

The purpose of this test is to evaluate the odor containment of the urine containment bag (UCB), P/N SDD46107234-306 in an environment simulating a spacecraft capsule. The goal is to determine the time of odor break through and the acceptability of the odor, once break through occurs. The goal is to simulate, as close as possible, the volume ratio (trash to free volume), trash content (vomit, urine, feces, and food trash), humidity and temperature of the capsule. The goal for minimum break through is 48 hours (Orion Block 0) from the start of the test. The goal for acceptability of odor is 2 weeks (including docked ISS time for Orion Block 0). Two UCB's will be tested simultaneously in different chambers. The one UCB will be tested empty, serving as a control. Odor break through will be based upon the when the filled UCB total organics exceeds that of the control (empty UCB) by a level detectable by a human panel (approximately 2 ppm).

Casper, Stephanie↗

Heat Melt Compactor Development Progress

The status of the Heat Melt Compactor (HMC) development project is reported. HMC Generation 2 (Gen 2) has been assembled and initial testing has begun. A baseline mission use case for trash volume reduction, water recovery, trash sterilization, and the venting of effluent gases and water vapor to space has been conceptualized. A test campaign to reduce technical risks is underway. This risk reduction testing examines the many varied operating scenarios and conditions needed for processing trash during a space mission. The test results along with performance characterization of HMC Gen 2 will be used to prescribe requirements and specifications for a future ISS flight Technology Demonstration. We report on the current status, technical risks, and test results in the context of an ISS vent-to-space Technology Demonstration.

ECLSS↗

A Review of Existing Policies Affecting the Jettison of Waste in Low Earth Orbit and Deep Space

The management of waste generated onboard spacecraft during future long-duration deep-space missions will require different solutions from those currently implemented on the International Space Station which consist exclusively of collecting, storing, and returning the waste to Earth. Alternative options for managing spacecraft waste are to process it for recycling and recovery of resources, and to jettison it overboard in a solid form (such as a compacted tile) or in a gaseous form after torrefaction or other trash-to-gas technologies. The waste generated during a deep-space mission is derived mainly from spacecraft logistics supplies, food and beverage residues, personal or scientific items used by the crew, human metabolic waste, and unused spare components. Uncontained and unprocessed trash is a potential health hazard and a habitat volume liability, which makes onboard long-term storage an inefficient and non-optimal option. However, the jettison of solid, processed waste appears to be an effective solution for crewed deep-space missions, leading not only to volume reduction and habitat safening, but also to considerable mass savings in the spacecraft’s propulsion system. However, the disposal of trash overboard also creates a navigation hazard for spacecraft and the potential risk of contamination of planetary bodies, interfering with the search for life. This paper investigates the requirements covered by existing policies that could affect the jettison concept of operations and system design.

Jettison↗

Microbial Characterization of Heat Melt Compaction for Treatment of Space Generated Solid Wastes

One treatment process in development for solid waste management in space has been the Trash Compaction Processing System (TCPS). Human space mission wastes typically contain large percentages of contaminated wet solid waste. The Heat Melt Compactor (HMC) is being developed to be a multi-function means of water recovery, volume reduction, and the making safe of contaminant-rich trash with the potential for waste stabilization and/or sterilization. To determine the efficacy of the HMC treatment to kill microorganisms in solid waste and remain biologically stable, testing was conducted on three tiles produced by HMC-Gen 2 at Ames Research Center. Samples were shipped to Kennedy Space Center to test for microbial viability after compaction, determine the bio-stability of the HMC disks during storage (43 days), and assess potential airborne contaminate microbial growth on surfaces at low and high humidity conditions. In addition to the products of solid waste processing technologies, there is a concern that the crew might come into contact with hardware surfaces that have been contaminated by microorganisms during waste processing. The extent of microbial surface contamination of waste processing hardware was determined by surface sample swabbing and analysis for total bacterial and yeast counts and cultivable counts of aerobic and anaerobic bacteria, spore-forming bacteria, and fungi. Results indicate that trash processing increased bacterial counts on the surfaces of the compacter. All but one biological indicator spore strip imbedded in the HMC produced tiles were negative for growth after incubation for five days indicating effective sterilization through the heat melt compaction process. Analysis of core samples as well as surface growth of tiles inoculated with Aspergillus niger fungal spores incubated at three levels of humidity indicate that HMC created tiles did not support the proliferation of bacterial and fungal growth.

Mary E Hummerick↗

Configuration and Projected Capabilities of the Common Habitat Medical Care Facility

The Common Habitat is a large, long-duration habitat being explored as part of a conceptual study (not an active NASA program) that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. Additional work outside the scope of this paper is developing a vertical translation system, a crew mobility aids system based on wearable gecko-derived grippers, and a crew seating/restraint system. These systems are all assumed for use in conjunction with the Medical Care Facility, which is needed to maintain crew well-being during these missions, where distance from Earth precludes the possibility of evacuation to Earth. This paper describes recent improvements in the Common Habitat Medical Care Facility and associated benefits for crew survivability in long duration missions beyond Earth orbit. These improvements were made with the assistance of a NASA Pathways intern whose experience includes a tour of duty in Afghanistan as an Army combat medic with the 691st GHOST-T, attached to the 1st and 7th US Special Forces Groups as part of Operation Freedom’s Sentinel, where he helped provide far-forward surgical capabilities in austere combat environments. The initial baseline Medical Care Facility was developed working in conjunction with University of Houston Space Architecture graduate students. The facility was placed on the upper deck of the Common Habitat in a location that provided privacy, operational volume, and was close to the vertical translation pathway. The notional outfitting repurposed component CAD models from unrelated studies and notionally indicated a level of care roughly equivalent to that aboard the International Space Station. The CAD modeling provided notional stowage volumes, a deployable surface, some fixed equipment, an ultrasound, and a potentially reconfigurable treatment table. While this facility is clearly a competent arrangement, it was desired to leverage available expertise and upgrade the station given the vast distances from Earth to be experienced by the Common Habitat. Key driving requirements applied to the upgrade included to provide Medical Level of Care V, offer enhanced telemedicine capabilities, provide patient physical accommodation, provide caregiver access to the patient from all sides, include sliding pocket doors for access to hygiene and to the Vertical Translation System, and to add any additional capability possible for the best achievable medical care. The first step in the facility upgrade was to quantify the current medical inventory on the International Space Station and ensure that sufficient stowage volume was present for this purpose. To that end, the ISS medical kits were reviewed, and eight full size mid deck lockers were placed in the facility. A number of additional devices were also added, based on the intern’s combat medic experience. Also, two fixed shelves and one horizontal work surface were added to the Medical Care Facility, with the shelves providing storage space for the additional devices and the work surface providing a location for the caregiver to work or stage equipment. Four display monitors were added to the wall above the horizontal work surface, supporting data display, telemedicine, conferencing, or other needs. The existing treatment table was replaced with a mobile surgical stretcher-chair. Two additional doors were added to the Medical Care Facility. One leads directly to the hygiene compartment, allowing it to support medical operations in addition to providing galley/wardroom support. The other door leads directly into the Vertical Translation System. The wall adjacent to the subsystems bay was moved, adding additional volume to the Medical Care Facility. This improved caregiver access to the patient and allowed for a larger number of caregivers to be present. It also provided options for relocation of support equipment relative to the patient as needed. In the upgraded Medical Care Facility, the Surgical Stretcher-Chair and the Vertical Translation System can work together to provide incapacitated crew member transport from a site of injury on any deck of the Common Habitat to the Medical Care Facility. It can also support patient treatment in a variety of positions including a variety of sitting postures and a supine posture at a variety of pitch angles. The facility can also support caregiver office work for review of examination results, private consultation, inventory and maintenance, and a variety of other purposes. A forward activity will be to conduct evaluations of the Medical Care Facility with different medical scenarios. Additionally, ambient and task lighting selections remain as forward work. The eight mid deck lockers can be augmented to use as portable equipment carts, similar to a manner in which maintenance facility stowage was used as portable carts during the NASA Desert Research and Technology Studies in the Constellation Program. Trash accommodation will also need forward work to assess, including provision for wet trash, dry trash, and biological waste. It will be important to assess a redesign of the surgical stretcher-chair. The commercial version used in the upgrade can only enable vertical translation in the seated configuration, requiring the patient to bend both hips and knees. A possible redesign of the chair will allow for vertical translation without requiring any bending at the hip or knees. Also, the commercial version is wheeled, making it mobile in gravity but unanchored in microgravity. Work will be needed to adapt the chair for gravity-independent performance. The hygiene compartment can be redesigned for dual-use medical scrub and galley handwash facility. Pending sufficient volume, it may also be possible to place sanitation equipment in this location to clean medical tools. Finally, most space architectures have never allowed for more than one incapacitated crew member, but several scenarios could potentially injure two or more crew in the same incident. This facility could be assessed to determine its present ability to address two or more injured crew in parallel and determine the potential upper limit for number of treatable crew in a multi-crew injury scenario, or to treat polytrauma of a single patient.

Habitat↗

Configuration and Projected Capabilities of the Common Habitat Medical Care Facility

The Common Habitat is a large, long-duration habitat being explored as part of a conceptual study (not an active NASA program) that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. Additional work outside the scope of this paper is developing a vertical translation system, a crew mobility aids system based on wearable gecko-derived grippers, and a crew seating/restraint system. These systems are all assumed for use in conjunction with the Medical Care Facility, which is needed to maintain crew well-being during these missions, where distance from Earth precludes the possibility of evacuation to Earth. This paper describes recent improvements in the Common Habitat Medical Care Facility and associated benefits for crew survivability in long duration missions beyond Earth orbit. These improvements were made with the assistance of a NASA Pathways intern whose experience includes a tour of duty in Afghanistan as an Army combat medic with the 691st GHOST-T, attached to the 1st and 7th US Special Forces Groups as part of Operation Freedom’s Sentinel, where he helped provide far-forward surgical capabilities in austere combat environments. The initial baseline Medical Care Facility was developed working in conjunction with University of Houston Space Architecture graduate students. The facility was placed on the upper deck of the Common Habitat in a location that provided privacy, operational volume, and was close to the vertical translation pathway. The notional outfitting repurposed component CAD models from unrelated studies and notionally indicated a level of care roughly equivalent to that aboard the International Space Station. The CAD modeling provided notional stowage volumes, a deployable surface, some fixed equipment, an ultrasound, and a potentially reconfigurable treatment table. While this facility is clearly a competent arrangement, it was desired to leverage available expertise and upgrade the station given the vast distances from Earth to be experienced by the Common Habitat. Key driving requirements applied to the upgrade included to provide NASA’s Medical Level of Care V, offer enhanced telemedicine capabilities, provide patient physical accommodation, provide caregiver access to the patient from all sides, include sliding pocket doors for access to hygiene and to the Vertical Translation System, and to add any additional capability possible for the best achievable medical care. The first step in the facility upgrade was to quantify the current medical inventory on the International Space Station and ensure that sufficient stowage volume was present for this purpose. To that end, the ISS medical kits were reviewed, and eight full size mid deck lockers were placed in the facility. A number of additional devices were also added, based on the co-author’s combat medic experience. Also, two fixed shelves and one horizontal work surface were added to the Medical Care Facility, with the shelves providing storage space for the additional devices and the work surface providing a location for the caregiver to work or stage equipment. Four display monitors were added to the wall above the horizontal work surface, supporting data display, telemedicine, conferencing, or other needs. The existing treatment table was replaced with a mobile surgical stretcher-chair. Two additional doors were added to the Medical Care Facility. One leads directly to the hygiene compartment, allowing it to support medical operations in addition to providing galley/wardroom support. The other door leads directly into the Vertical Translation System. The wall adjacent to the subsystems bay was moved, adding additional volume to the Medical Care Facility. This improved caregiver access to the patient and allowed for a larger number of caregivers to be present. It also provided options for relocation of support equipment relative to the patient as needed. In the upgraded Medical Care Facility, the Surgical Stretcher-Chair and the Vertical Translation System can work together to provide incapacitated crew member transport from a site of injury on any deck of the Common Habitat to the Medical Care Facility. It can also support patient treatment in a variety of positions including a variety of sitting postures and a supine posture at a variety of pitch angles. The facility can also support caregiver office work for review of examination results, private consultation, inventory and maintenance, and a variety of other purposes. A forward activity will be to conduct evaluations of the Medical Care Facility with different medical scenarios. Additionally, ambient and task lighting selections remain as forward work. The eight middeck lockers can be augmented to use as portable equipment carts, similar to a manner in which maintenance facility stowage was used as portable carts during the NASA Desert Research and Technology Studies in the Constellation Program. Trash accommodation will also need forward work to assess, including provision for wet trash, dry trash, and biological waste. It will be important to assess a redesign of the surgical stretcher-chair. The commercial version used in the upgrade can only enable vertical translation in the seated configuration, requiring the patient to bend both hips and knees. A possible redesign of the chair will allow for vertical translation without requiring any bending at the hip or knees. Also, the commercial version is wheeled, making it mobile in gravity but unanchored in microgravity. Work will be needed to adapt the chair for gravity-independent performance. The hygiene compartment can be redesigned to serve both as a medical scrub facility and for galley hand washing. Pending sufficient volume, it may also be possible to place sanitation equipment in this location to clean medical tools. Finally, most space architectures have never allowed for more than one incapacitated crew member, but several scenarios could potentially injure two or more crew in the same incident. This facility could be assessed to determine its present ability to address two or more injured crew in parallel and determine the potential upper limit for number of treatable crew in a multi-crew injury scenario, or to treat polytrauma of a single patient.

Common Habitat↗

Waste Materials Recycling for In-Space Manufacturing

Logistics and resupply payloads for Lunar and Martian missions are significantly more cost and schedule prohibitive compared to LEO destinations. Recycling of waste and trash materials generated throughout the duration of a mission, as well as previous missions, will be critical for enabling sustained human presence beyond Earth. Currently, no solution exists for recycling waste materials back into feedstock form beyond entry-level hobbyist equipment, which is not suitable nor practical for space applications. There is already over 500,000 lbs of trash on the moon from previous missions, which will grow exponentially over the coming decade throughout the Artemis Campaign. Waste and trash materials are precious resources that, if recovered and properly processed, can be transformed back into usable feedstock form for on-demand manufacturing capabilities. Hence, it is prudent that a recycling solution be developed and infused into future missions.

additive↗

Gas Effluent Analysis of the Heat Melt Compactor

The Heat Melt Compactor (HMC) reduces volume, heat sterilizes, stabilizes, and manages gas and water effluent of the International Space Station (ISS) trash. Processing the trash at high temperatures produces volatile gas compounds that need to be treated before venting to cabin and/or the Vacuum Exhaust System (VES) in the ISS. The release of gases may not meet the Spacecraft Maximum Allowable Concentrations (SMAC) requirement, if vented directly into cabin, and/or gases are incompatible for venting to the VES. In order to assess the HMC gas release and venting parameters, effluent gas analysis is conducted to determine contaminant load. This paper will analyze different collection and analytical methods of the effluent gas, and report corresponding data, such that these results can be used for process design and effluent management.

Heat Melt Compactor↗

Turning Gas into Greens

Scientists from Cook College, Rutgers University, and Stevens Institute of Technology conducted studies to create an experimental greenhouse that uses methane from decomposing trash to fuel a system that makes food. Biogasses created by the anaerobically decomposing trash are necessary to fulfill the energy needs of this revolutionary greenhouse. The primary emission, methane, is piped to the greenhouse boiler and used to fuel the hot water heating system. Thus far, the use of biogas has drastically reduced the operating costs of the greenhouse, eliminating the need for non-renewable fuels. The biogas will also generate electricity for the greenhouse in the near future. The plants are irrigated with recycled plant nutrients such as nitrogen, phosphorus, potassium, calcium, and magnesium. These nutrients are delivered through hydroponics, the cultivation of plants in a nutrient solution rather than in soil. High-pressure sodium lamps augment the natural light, thereby boosting production and reducing cropping time. A total of 16 hours of light are provided to the crop each day, year-round. It only takes about 90 days for a seed to germinate and produce a tomato harvest. Not only is the food produced faster, the manual labor needed for the upkeep of the plants is also drastically reduced.

Source record↗

Mower/Litter Removal

The Burg Corporation needed to get more power out of the suction system in their Vac 'N Bag grass mower/litter remover. The president submitted a problem statement to the Marshall Space Flight Center Technology Transfer Office, which devised a way to guide heavier items of trash to a point where suction was greatest, and made changes to the impeller and the exhaust port, based on rocket propulsion technology. The improved system is used by highway departments, city governments and park authorities, reducing work time by combining the tasks of grass cutting and vacuuming trash and grass clippings.

Source record↗

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

NASA Center KSC↗

Microbial Characterization of Solid-Wastes Treated with Heat Melt Compaction Technology

The research purpose of the project was to determine the fate of microorganisms in space-generated solid wastes after processing by a Heat Melt Compactor (HMC), which is a candidate solid waste treatment technology. Five HMC product disks were generated at Ames Research Center (ARC), Waste Management Systems element. The feed for two was simulated space-generated trash and feed for three was Volume F compartment wet waste returned on STS 130. Conventional microbiological methods were used to detect and enumerate microorganisms in HMC disks and in surface swab samples of HMC hardware before and after operation. Also, biological indicator test strips were added to the STS trash prior to compaction to test if HMC processing conditions, 150 C for approx 3 hr and dehydration, were sufficient to eliminate the test bacteria on the strips. During sample acquisition at KSC, the HMC disk surfaces were sanitized with 70% alcohol to prevent contamination of disk interiors. Results from microbiological assays indicated that numbers of microbes were greatly reduced but not eliminated by the 70% alcohol. Ten 1.25 cm diameter cores were aseptically cut from each disk to sample the disk interior. The core material was run through the microbial characterization analyses after dispersal in sterile diluent. Low counts of viable bacteria (5 to 50 per core) were found but total direct counts were 6 to 8 orders of magnitude greater. These results indicate that the HMC operating conditions might not be sufficient for complete waste sterilization, but the vast majority of microbes present in the wastes were dead or non-cultivable after HMC treatment. The results obtained from analyses of the commercial spore test strips that had been added fo the wastes prior to HMC operation further indicated that the HMC was sterilizing the wastes. Nearly all strips were recovered from the HMC disks and all of these were negative for spore growth when run through the manufacturer's protocol. The 10(exp 6) or so spores impregnated into the strips were no longer viable. Control test strips, i.e., not exposed to the HMC conditions, were all strongly positive. All isolates from the cultivable counts were identified, leading to one concern: several were identified as Staphylococcus aureus, a human pathogen. The project reported here provides microbial characterization support to the Waste Management Systems element of the Life Support and Habitation Systems program.

Strayer, Richard F.↗

Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production

The Trash to Gas (TtG) project investigates technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA's Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluates catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.

energy conversion↗