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Over the last three years, the University of Utah (UofU), NASA Ames Research Center (ARC), and Reaction Engineering International (REI) have been developing an incineration system for the regeneration of components in waste materials for long-term life support systems. The system includes a fluidized bed combustor and a catalytic flue gas clean up system. An experimental version of the incinerator was built at the UofU. The incinerator was tested and modified at ARC and then operated during the Phase III human testing at NASA Johnson Space Center (JSC) during 1997. This paper presents the results of the work at the three locations: the design and testing at UofU, the testing and modification at ARC, and the integration and operation during the Phase III tests at JSC.

This paper offers a concept for a regenerable, low-power system for purifying exhaust from a solid waste processor. The innovations in the concept include the use of a closed-loop regeneration cycle for the adsorber, which prevents contaminants from reaching the breathable air before they are destroyed, and the use of a humidity-swing desorption cycle, which uses less power than a thermal desorption cycle and requires no venting of air and water to space vacuum or planetary atmosphere. The process would also serve well as a trace contaminant control system for the air in the closed environment. A systems-level design is presented that shows how both the exhaust and air purification tasks could be performed by one processor. Data measured with a fixed-bed apparatus demonstrate the effects of the humidity swing on regeneration of the adsorbent.

A volatile organic analyzer (VOA), developed by Graseby Dynamics, Ltd. under contract to the Johnson Space Center Toxicology Laboratory, is the core instrument for trace contaminant monitoring on the International Space Station (ISS). The VOA will allow trace amounts of target compounds to be analyzed in real time so that ISS air quality can be assessed in nominal and contingency situations. Recent events on Mir have underscored the need for real-time analysis of air quality so that the crew can respond promptly during off-nominal conditions. The VOA, which is based on gas chromatography/ion mobility spectrometry, is the first spacecraft instrument to be used for such a complex task. Consequently, a risk mitigation experiment (VOA/RME) was flown to assess the performance and engineering aspects of the VOA. This paper is a review of VOA/RME results from the STS-81 and STS-89 flights and their implications for the ISS VOA design and operations.

The docking and integration of the Priroda module into the Space Station Mir Complex in 1996 provided a unique opportunity to assess the potential impact on the trace contaminant concentrations in the station complex. Since Priroda was substantially loaded with new US flight hardware, the data are potentially relevant to future similar operations associated with the buildup of the International Space Station. Grab samples were collected to assess the Priroda concentrations prior to integration and to capture the profile of concentrations after the start of Priroda inter-module ventilation. A long term time integrated sampler was configured for collection of canister samples over a time interval of seven days.

The complexity of the atmosphere aboard the International Space Station (ISS) will require a multifaceted monitoring strategy for both nominal and emergency conditions to protect the health and safety of the crew. Samples to be collected for air-quality assessment will include both archival sampling for ground analysis and on-board automatic analyses. Archival samples will be analyzed after return by standard gas chromatography/mass spectrometry; a separate formaldehyde analysis will be conducted as well. On-orbit analyses are planned for specific combustion products and for specific volatile organic compounds of toxicological significance. The air-lock will be monitored after EVAs to ensure that no propellants are introduced into the cabin atmosphere. Additional remote samples can be collected in sample bags from other ISS elements and brought to the Volatile Organic Analyzer (VOA) for analysis.

The recent development of a collection of techniques referred to as direct sampling ion trap mass spectrometry (DSITMS) shows great promise for real-time, high-throughput, low-cost screening of environmental pollutants in air. One of its great strengths is the flexibility it allows the user in choosing among different sample introduction systems, ionization modes, and scan modes. This paper delineates the various stages involved in a DSITMS analysis, describes the options and great flexibility inherent in each of these stages, and demonstrates the use of DSITMS techniques for monitoring trace levels of volatile organic compounds (VOCs) in Mir space station air samples.

Mass transfer of plant and human nutritional minerals in a Biological Advanced Life Support (BALS) were simulated to determine if deficiencies or toxic levels of minerals would develop in plant or human diets in a BALS. Scenarios of mineral recovery were simulated to determine if harmful levels of minerals develop in the human diet and in the nutrient solution, how long the nutrient solution could be used before toxic concentrations exist in the solution, and the level of mineral resupplied needed to support a BALS. Results indicated that the human diet is deficient in some mineral levels, and contains excess, but not harmful, levels of many minerals. Plant deficiency levels and the accumulation of toxic concentrations of minerals in the nutrient system were dependent on the recovery of minerals in the bioreactor

ALS metrics are required to meet congressional requirements, but if they are well thought out will help focus technical efforts in appropriate and productive directions. This paper addresses the benefits and limitations of using equivalent system mass as an ALS metric.

A steady-state system mass balance calculation was performed to investigate design issues regarding the storage and/or processing of solid waste. In the initial stages of BIO-Plex, only a certain percentage of the food requirement will be satisfied through crop growth. Since some food will be supplied to the system, an equivalent amount of waste will accumulate somewhere in the system. It is a system design choice as to where the mass should accumulate in the system. Here we consider two approaches. One is to let solid waste accumulate in order to reduce the amount of material processing that is needed. The second is to process all of the solid waste to reduce solid waste storage and then either resupply oxygen or add physical/chemical (P/C) processors to recover oxygen from the excess carbon dioxide and water that is produced by the solid waste processor.

Excessive impact pressures can develop when an evacuated system is filled with liquid. Such a process is usually highly chaotic, especially when the system geometry is complex. Available computational methods by themselves cannot provide the necessary answers. The International Space Station (ISS) heat exchanger has a complex flow system, and a synthesis of computational and experimental methods was necessary to design the system. The FLOW-NET two-phase flow program was used to determine the range of loss coefficients and the liquid-vapor interface mass and energy transfer that would fit the measured impact pressures. These loss coefficients could then be used to compute the impact pressures for a design configuration similar to the one tested at a range of operating conditions.

The Test and Verification (T&V) approach for the thermal control systems of the ISS involves a combination of test, analysis and other approaches to confirm that the design meets ISS requirements. The maturity of the designs used in ISS varies from a design for Functional Cargo Block (FGB) that has been proven to be functional on the Mir space station to new design developments for heat pipe passive cooling networks and single phase ammonia systems for thermal conditioning of the USOS. The approach to thermal T&V considers the design maturity and the nature of the system under evaluation. The approach for each area of the ISS is described in this paper as is the status of the T&V activities. In addition to the approach taken in each area, an overview of the results obtained is provided.

A test program for two Pressurized Mating Adapter (PMA-1) Multiplxer/Demultiplexer (MDM) heat pipe radiator assemblies was successfully conducted at the Boeing Space & Defense Systems in Huntington Beach, California. The program objectives were to verify that the test articles would function after being exposed to simulated cargo bay acoustic loads and thermal cycling stresses in the worst case on-orbit environment. This paper presents the testing approach, setup, instrumentation, procedures and results. Correlation of the mathematical model with the test results is also presented.

The Heat Rejection Subsystem (HRS) Radiators Orbital Replaceable Unit (ORU) for the International Space Station has undergone thermal vacuum qualification testing at NASA Plum Brook Station, Space Power Facility in Ohio. The testing was conducted from December 1996 through January 1997 and October 4 through 18, 1997. This testing included confirmation of the heater control assembly (HCA) and heater performance that was initially tested during December 1996 through January 1997. Deployment system functional operations were tested for both hot and cold conditions using both the Integrated Motor Control Assembly (IMCA) and the Extravehicular Activity (EVA) drive.

Neural networks for whole ion mobility spectra from a standardized data base of 1295 spectra for 195 chemicals at various concentrations showed 92% successful classifications by functional group was throughout a range of concentrations. Application of neural networks in a two tier design where chemicals were first identified by class and as individual substances eliminated all but one false positive out of 161 test spectra. These findings establish that ion mobility spectra, even with low resolution instrumentation, contain sufficient detail to permit development of automated identification systems. Under certain conditions of temperature and moisture in the IMS drift tube, the identification of “blind unknowns” was better than 90%. This suggests that the volatile organic analyzer can be extended to completely unknown chemicals during air quality monitoring.

We are developing and testing a small, efficient time-of-flight mass spectrometer to rapidly identify important biomarkers for human space exploration. We are also evaluating critical biomarkers that are indicators of muscle atrophy and bone demineralization associated with space travel. We have recorded mass spectral signatures of several biomarkers. Compounds under investigation include: insulin-like growth factors (IGF-I), urinary 3-methylhistidine, estradiol, and creatinine. We have also completed initial studies of trivalent hydroxypyridinium crosslinks which are excreted as free pyridinolines in urine during bone resorption.

The monitoring of trace pollutants in spacecraft air is essential to protect the crew from harmful exposures. Monitoring requirements are focused on those sources of pollutants that pose the highest risk to crew health. Deciding which sources pose the greatest risk is done based on years of experience with the Space Shuttle, and more recently with the Russian Mir space station. Combustion of nonmetallic materials associated with electric circuits or heat-generating devices poses the greatest risk to crew health. Major leaks of fluids from systems or payloads also pose a significant risk. Other potential risks include accumulation of metabolites, entry of propellants, and excess offgassing, especially in modules that have been sealed for long periods.

Reliable data on human metabolic materials are essential for designing environmental control and life support systems (ECLSS) in manned space facilities. This paper presents results from detailed analyses of human metabolic gases, including trace gases, breath, and water vapor collected from twenty healthy subjects of Japanese, and of urine from thirty-three volunteers that was stored at room temperature and at low temperature for seven days. The most SMAC-critical trace gas was carbon monoxide, which was detected in abundance in smoker's breath samples. The urine preserved at room temperature for one week indicated remarkable changes in constituent concentrations, suggesting metabolic activity of microorganisms in the urine sample. These results are being used to develop, test, and operate a trace contaminant removal system and the water reclamation system for a regenerative ECLSS, to evaluate the efficiency of the systems, and to monitor the quality of the closed environment.

The Photovoltaic Radiator (PVR) is designed to reject waste heat of the Early External Active Thermal Control System (EEATCS) and the Photovoltaic Thermal Control System (PV TCS) of the International Space Station (ISS). Two EEATCS PVR units and one PV TCS PVR unit will be on the Assured Early Research (AER) phase of the ISS and all four PV TCS PVR units will be on the assembly complete configuration of the ISS. Thermal environments of the AER mission and assembly complete configuration present challenging thermal designs to maintain the EEATCS and PV TCS PVR units functioning within the temperature operating limits of the structural components and the ammonia fluid.

Diverse modeling information is needed for system modeling and simulation for the purposes of developing, testing and supporting intelligent layered software for planning/scheduling, monitoring, control and fault management for test articles in BIO-Plex. A framework of types of system management goals is used to provide perspective for integrated discussion of the diverse modeling and control approaches. This paper discusses model representations in the CONFIG discrete-event modeling and simulation tool, which are used to link diverse modeling styles, to support integrated use and reuse of diverse modeling information.

Large-scale physical system development endeavors which employ advanced systems methods require close technical/scientific interaction among a diverse group of mathematical modeling practitioners. A number of highly rigorous, highly rigid methods are available for the “book-keeping” necessary for valid mathematical modeling of systems of power exchanging “continuous” physical processes. Each method is attractive for one or more specialized physical scenarios, but none has become universally accepted because all are awkward in one or more important circumstances. In this paper, a means of incorporating all these representations (including ad hoc representations) into a single system representation is presented.