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At least 91 records · Page 5

Zeno: Critical Fluid Light Scattering Experiment

The Zeno (Critical Fluid Light Scattering) experiment is the culmination of a long history of critical fluid light scattering in liquid-vapor systems. The major limitation to making accurate measurements closer to the critical point was the density stratification which occurs in these extremely compressible fluids. Zeno was to determine the critical density fluctuation decay rates at a pair of supplementary angles in the temperature range 100 mK to 100 (mu)K from T(sub c) in a sample of xenon accurately loaded to the critical density. This paper gives some highlights from operating the instrument on two flights March, 1994 on STS-62 and February, 1996 on STS-75. More detail of the experiment Science Requirements, the personnel, apparatus, and results are displayed on the Web homepage at http://www.zeno.umd.edu.

Gammon, Robert W.↗

High-Pressure Oxygen Generation for Outpost EVA Study

The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

Jeng, Frank F.↗

Status of the Space Station water reclamation and management subsystem design concept

A development status report is presented for the NASA Space Station's water reclamation and management (WRM) system, for which the candidate phase change-employing processing technologies are an air evaporation subsystem, a thermoelectric integrated membrane evaporation subsystem, and the vapor compression distillation subsystem. These WRM candidates employ evaporation to effect water removal from contaminants, but differ in their control of the vapor/liquid interface in zero-gravity and in the recovery of the latent heat of vaporization.

Bagdigian, R. M.↗

Regenerative Life Support Evaluation

This paper describes the development plan and design concept of the Regenerative Life Support Evaluation (RLSE) planned for flight testing in the European Space Agency Spacelab. The development plan encompasses the ongoing advanced life support subsystem and a systems integration effort to evolve concurrently subsystem concepts that perform their function and can be integrated with other subsystems in a flight demonstration of a regenerative life support system. The design concept for RLSE comprises water-electrolysis O2 generation, electrochemically depolarized CO2 removal, and Sabatier CO2 reduction for atmosphere regeneration, urine vapor-compression distillation, and wash-water hyperfiltration for waste-water recovery. The flight demonstration by RLSE is an important step in qualifying the regenerative concepts for life support in space stations.

Kleiner, G. N.↗

Controlled ecological life support systems; Proceedings of Workshop II of the 26th COSPAR Plenary Meeting, Toulouse, France, June 30-July 11, 1986

The present conference on the development status of Controlled Ecological Life Support Systems (CELSSs) discusses food production and gas exchange with the Spirulina blue-green alga, biomass recycling for greater energy efficiency in algal culture CELSSs, algal proteins for food processing in a CELSS, a CELSS with photosynthetic N2-fixing cyanobacteria, the NASA CELSS program, and vapor compression ditillation and membrane technology for water revitalization. Also discussed are a fundamental study of CELSS gas monitoring, the application of catalytic wet oxidation to CELSS, a large-scale perspective on ecosystems, Japanese CELSS research activities, the use of potatoes in bioregenerative life-support, wheat production in controlled environments, and a trickle water and feeding system in plant culture.

Macelroy, R. D.↗

Mechanical properties testing and results for thermal barrier coatings

Thermal Barrier Coatings (TBC's) provide a significant challenge in the evaluation of their mechanical properties in ways that provide data that is not specimen dependent. The paper reviews various developments of the principal author over the past several years for both plasma sprayed and physical vapor deposited (PVD) materials, as well as new data on the fatigue behavior of one material system. The test methods that have been employed address tensile and compressive modulus and ultimate strength, tensile and compressive fatigue strength, and interfacial strength. This testing is now underway. Property testing is especially difficult for TBC's owing to the limitation on fabrication thickness of the coating. Bending tests are not used as these tests do not provide sufficiently uniform states of strain for property evaluations. Test specimens with uniform states of axial stress have been devised for each material system. The results show that the material property results between various experimenters and experimental methods are not yet consistent. However, the results provide critical design data at a suitable level of accuracy for life prediction. The paper will review both tensile and compressive mechanical testing of uniaxial specimens showing property dependencies on material density and temperatures for both material systems. Successful test results for both tensile and compressive fatigue loadings will be given. The test data shows that the fatigue strength of the TBC's is highly stress dependent in both loading conditions and is likely to depend on stress range and not mean stress. The fatigue strength of the plasma sprayed TBC's appears to increase with elevated temperatures in a range of temperatures below the creep activation temperature for the materials. The plasma sprayed TBC materials have been confirmed to have cyclic hysteresis at all temperature levels down to room temperature. Limited failure analysis data for various specimens suggest that the failure modes are driven by normal geometric discontinuities in the TBC's.

Cruse, T. A.↗

NASA Tech Briefs, March 2010

Topics covered include: Software Tool Integrating Data Flow Diagrams and Petri Nets; Adaptive Nulling for Interferometric Detection of Planets; Reducing the Volume of NASA Earth-Science Data; Reception of Multiple Telemetry Signals via One Dish Antenna; Space-Qualified Traveling-Wave Tube; Smart Power Supply for Battery-Powered Systems; Parallel Processing of Broad-Band PPM Signals; Inexpensive Implementation of Many Strain Gauges; Constant-Differential-Pressure Two-Fluid Accumulator; Inflatable Tubular Structures Rigidized with Foams; Power Generator with Thermo-Differential Modules; Mechanical Extraction of Power From Ocean Currents and Tides; Nitrous Oxide/Paraffin Hybrid Rocket Engines; Optimized Li-Ion Electrolytes Containing Fluorinated Ester Co-Solvents; Probabilistic Multi-Factor Interaction Model for Complex Material Behavior; Foldable Instrumented Bits for Ultrasonic/Sonic Penetrators; Compact Rare Earth Emitter Hollow Cathode; High-Precision Shape Control of In-Space Deployable Large Membrane/Thin-Shell Reflectors; Rapid Active Sampling Package; Miniature Lightweight Ion Pump; Cryogenic Transport of High-Pressure-System Recharge Gas; Water-Vapor Raman Lidar System Reaches Higher Altitude; Compact Ku-Band T/R Module for High-Resolution Radar Imaging of Cold Land Processes; Wide-Field-of-View, High-Resolution, Stereoscopic Imager; Electrical Capacitance Volume Tomography with High-Contrast Dielectrics; Wavefront Control and Image Restoration with Less Computing; Polarization Imaging Apparatus; Stereoscopic Machine-Vision System Using Projected Circles; Metal Vapor Arcing Risk Assessment Tool; Performance Bounds on Two Concatenated, Interleaved Codes; Parameterizing Coefficients of a POD-Based Dynamical System; Confidence-Based Feature Acquisition; Algorithm for Lossless Compression of Calibrated Hyperspectral Imagery; Universal Decoder for PPM of any Order; Algorithm for Stabilizing a POD-Based Dynamical System; Mission Reliability Estimation for Repairable Robot Teams; Processing AIRS Scientific Data Through Level 3; Web-Based Requesting and Scheduling Use of Facilities; AutoGen Version 5.0; Time-Tag Generation Script; PPM Receiver Implemented in Software; Tropospheric Emission Spectrometer Product File Readers; Reporting Differences Between Spacecraft Sequence Files; Coordinating "Execute" Data for ISS and Space Shuttle; Database for Safety-Oriented Tracking of Chemicals; Apparatus for Cold, Pressurized Biogeochemical Experiments; Growing B Lymphocytes in a Three-Dimensional Culture System; Tissue-like 3D Assemblies of Human Broncho-Epithelial Cells; Isolation of Resistance-Bearing Microorganisms; Oscillating Cell Culture Bioreactor; and Liquid Cooling/Warming Garment.

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Refurbishment of one-person regenerative air revitalization system

Regenerative processes for the revitalization of spacecraft atmospheres and reclamation of waste waters are essential for making long-term manned space missions a reality. Processes studied include: static feed water electrolysis for oxygen generation, Bosch carbon dioxide reduction, electrochemical carbon dioxide concentration, vapor compression distillation water recovery, and iodine monitoring. The objectives were to: provide engineering support to Marshall Space Flight Center personnel throughout all phases of the test program, e.g., planning through data analysis; fabricate, test, and deliver to Marshall Space Flight Center an electrochemical carbon dioxide module and test stand; fabricate and deliver an iodine monitor; evaluate the electrochemical carbon dioxide concentrator subsystem configuration and its ability to ensure safe utilization of hydrogen gas; evaluate techniques for recovering oxygen from a product oxygen and carbon dioxide stream; and evaluate the performance of an electrochemical carbon dioxide concentrator module to operate without hydrogen as a method of safe haven operation. Each of the tasks were related in that all focused on providing a better understanding of the function, operation, and performance of developmental pieces of environmental control and life support system hardware.

Powell, Ferolyn T.↗

Controlling Gas-Flow Mass Ratios

Proposed system automatically controls proportions of gases flowing in supply lines. Conceived for control of oxidizer-to-fuel ratio in new gaseous-propellant rocket engines. Gas-flow control system measures temperatures and pressures at various points. From data, calculates control voltages for electronic pressure regulators for oxygen and hydrogen. System includes commercially available components. Applicable to control of mass ratios in such gaseous industrial processes as chemical-vapor depostion of semiconductor materials and in automotive engines operating on compressed natural gas.

Morris, Brian G.↗

Performance Assessment of the Exploration Water Recovery System

A new water recovery system architecture designed to fulfill the National Aeronautics and Space Administration s (NASA) Space Exploration Policy has been tested at the Marshall Space Flight Center (MSFC). This water recovery system architecture evolved from the current state-of-the-art system developed for the International Space Station (ISS). Through novel integration of proven technologies for air and water purification, this system promises to elevate existing system optimization. The novel aspect of the system is twofold. First, volatile organic compounds (VOC) are removed from the cabin air via catalytic oxidation in the vapor phase, prior to their absorption into the aqueous phase. Second, vapor compression distillation (VCD) technology processes the condensate and hygiene waste streams in addition to the urine waste stream. Oxidation kinetics dictate that removing VOCs from the vapor phase is more efficient. Treating the various waste streams by VCD reduces the load on the expendable ion exchange and adsorption media which follows, as well as the aqueous-phase catalytic oxidation process further downstream. This paper documents the results of testing this new architecture.

Carter. D. Layne↗

Geostationary Imaging FTS (GIFTS) Data Processing: Measurement Simulation and Compression

GIFTS (Geostationary Imaging Fourier Transform Spectrometer), a forerunner of next generation geostationary satellite weather observing systems, will be built to fly on the NASA EO-3 geostationary orbit mission in 2004 to demonstrate the use of large area detector arrays and readouts. Timely high spatial resolution images and quantitative soundings of clouds, water vapor, temperature, and pollutants of the atmosphere for weather prediction and air quality monitoring will be achieved. GIFTS is novel in terms of providing many scientific returns that traditionally can only be achieved by separate advanced imaging and sounding systems. GIFTS' ability to obtain half-hourly high vertical density wind over the full earth disk is revolutionary. However, these new technologies bring forth many challenges for data transmission, archiving, and geophysical data processing. In this paper, we will focus on the aspect of data volume and downlink issues by conducting a GIFTS data compression experiment. We will discuss the scenario of using principal component analysis as a foundation for atmospheric data retrieval and compression of uncalibrated and un-normalized interferograms. The effects of compression on the degradation of the signal and noise reduction in interferogram and spectral domains will be highlighted. A simulation system developed to model the GIFTS instrument measurements is described in detail.

Huang, Hung-Lung↗

Lunar base heat pump, phase 1

This report describes the Phase 1 process and analysis used to select a refrigerant and thermodynamic cycle as the basis of a vapor compression heat pump requiring a high temperature lift, then to perform a preliminary design to implement the selected concept, including major component selection. Use of a vapor compression heat pump versus other types was based on prior work performed for the Electric Power Research Institute. A high lift heat pump is needed to enable a thermal control system to remove heat down to 275 K from a habitable volume when the external thermal environment is severe. For example, a long-term lunar base habitat will reject heat from a space radiator to a 325 K environment. The first step in the selection process was to perform an optimization trade study, quantifying the effect of radiator operating temperature and heat pump efficiency on total system mass; then, select the radiator operating temperature corresponding to the lowest system mass. Total system mass included radiators, all heat pump components, and the power supply system. The study showed that lunar night operation, with no temperature lift, dictated the radiator size. To operate otherwise would require a high mass penalty to store power. With the defined radiation surface, and heat pump performances assumed to be from 40 percent to 60 percent of the Carnot ideal, the optimum heat rejection temperature ranged from 387 K to 377 K, as a function of heat pump performance. Refrigerant and thermodynamic cycles were then selected to best meet the previously determined design conditions. The system was then adapted as a ground-based prototype lifting temperature to 360 K (versus 385 K for flight unit) and using readily available commercial-grade components. Over 40 refrigerants, separated into wet and dry compression behavioral types, were considered in the selection process. Refrigerants were initially screened for acceptable critical temperature. The acceptable refrigerants were analyzed in ideal single and two-stage thermodynamic cycles. Top candidates were analyzed assuming realistic component limits and system pressure drops, and were evaluated for other considerations such as safety, environmental impact, and commercial availability. A maximum coefficient of performance (COP) of 56 percent of the Carnot ideal was achievable for a three-stage CFC-11 cycle operating under the flight conditions above. The program was completed by defining a control scheme and by researching and selecting the major components, compressor and heat exchangers, that could be used to implement the thermodynamic cycle selected. Special attention was paid to using similar technologies for the SIRF and flight heat pumps resulting in the commercially available equivalent of the flight unit. A package concept was generated for the components selected and mass and volume estimated.

Goldman, Jeffrey H.↗

Vapor Compression Distillation Subsystem (VCDS) Component Enhancement, Testing and Expert Fault Diagnostics Development, Volume 2

A wide variety of Space Station functions will be managed via computerized controls. Many of these functions are at the same time very complex and very critical to the operation of the Space Station. The Environmental Control and Life Support System is one group of very complex and critical subsystems which directly affects the ability of the crew to perform their mission. Failure of the Environmental Control and Life Support Subsystems are to be avoided and, in the event of failure, repair must be effected as rapidly as possible. Due to the complex and diverse nature of the subsystems, it is not possible to train the Space Station crew to be experts in the operation of all of the subsystems. By applying the concepts of computer-based expert systems, it may be possible to provide the necessary expertise for these subsystems in dedicated controllers. In this way, an expert system could avoid failures and extend the operating time of the subsystems even in the event of failure of some components, and could reduce the time to repair by being able to pinpoint the cause of a failure when one cannot be avoided.

Mallinak, E. S.↗

Water reclamation technology development for future long range missions

This paper covers the development of computer simulation models of the Vapor Compression Distillation (VCD) process, the Super Critical Water Oxidation (SCWO) process, and two versions of a Vapor Phase Catalytic Ammonia Reduction (VPCAR) process. These process level models have combined into two Integrated Water Reclamation Systems (IWRS). Results from these integrated models, in conjunction with other data sources, have been used to develop a preliminary comparison of the two systems. Also discussed in this paper is the development of a Vapor Phase Catalytic Ammonia Reduction teststand and the development of a new urine analog for use with the teststand and computer models.

Flynn, Michael T.↗

Orbital spacecraft resupply technology

The resupplying of orbital spacecraft using the Space Shuttle, Orbital Maneuvering Vehicle, Orbital Transfer Vehicle or a depot supply at a Space Station is studied. The governing factor in fluid resupply designs is the system size with respect to fluid resupply quantities. Spacecraft propellant management for tankage via diaphragm or surface tension configurations is examined. The capabilities, operation, and application of adiabatic ullage compression, ullage exchange, vent/fill/repressurize, and drain/vent/no-vent fill/repressurize, which are proposed transfer methods for spacecraft utilizing tankage configurations, are described. Selection of the appropriate resupply method is dependent on the spacecraft design features. Hydrazine adiabatic compression/detonation, liquid-free vapor venting to prevent freezing, and a method for no-vent liquid filling are analyzed. Various procedures for accurate measurements of propellant mass in low gravity are evaluated; a system of flowmeters with a PVT system was selected as the pressurant solubility and quantity gaging technique. Monopropellant and bipropellant orbital spacecraft consumable resupply system tanks which resupply 3000 lb of hydrazine and 7000 lb of MMH/NTO to spacecraft on orbit are presented.

Eberhardt, R. N.↗

Composite impact strength improvement through a fiber/matrix interphase

Research was conducted to improve the impact strength and toughness of fiber/resin composites by means of a fiber coating interphase. Graphite fiber/epoxy resin composites were fabricated with four different fiber coating systems introduced in a matrix-fiber interphase. Two graphite fibers, a high strength and a high modulus type, were studied with the following coating systems: chemical vapor deposited boron, electroless nickel, a polyamide-imide resin and a thermoplastic polysulfone resin. Evaluation methods included the following tests: Izod, flexure, shear fracture toughness, longitudinal and transverse tensile, and transverse and longitudinal compression. No desirable changes could be effected with the high strength fiber, but significant improvements in impact performance were observed with the polyamide-imide resin coated high modulus fiber with no loss in composite modulus.

Cavano, P. J.↗

Waste water processing technology for Space Station Freedom - Comparative test data analysis

Comparative tests were conducted to choose the optimum technology for waste water processing on SSF. A thermoelectric integrated membrane evaporation (TIMES) subsystem and a vapor compression distillation subsystem (VCD) were built and tested to compare urine processing capability. Water quality, performance, and specific energy were compared for conceptual designs intended to function as part of the water recovery and management system of SSF. The VCD is considered the most mature and efficient technology and was selected to replace the TIMES as the baseline urine processor for SSF.

Miernik, Janie H.↗

Remote sensing science for the Nineties; Proceedings of IGARSS '90 - 10th Annual International Geoscience and Remote Sensing Symposium, University of Maryland, College Park, May 20-24, 1990. Vols. 1, 2, & 3

Various papers on remote sensing (RS) for the nineties are presented. The general topics addressed include: subsurface methods, radar scattering, oceanography, microwave models, atmospheric correction, passive microwave systems, RS in tropical forests, moderate resolution land analysis, SAR geometry and SNR improvement, image analysis, inversion and signal processing for geoscience, surface scattering, rain measurements, sensor calibration, wind measurements, terrestrial ecology, agriculture, geometric registration, subsurface sediment geology, radar modulation mechanisms, radar ocean scattering, SAR calibration, airborne radar systems, water vapor retrieval, forest ecosystem dynamics, land analysis, multisensor data fusion. Also considered are: geologic RS, RS sensor optical measurements, RS of snow, temperature retrieval, vegetation structure, global change, artificial intelligence, SAR processing techniques, geologic RS field experiment, stochastic modeling, topography and Digital Elevation model, SAR ocean waves, spaceborne lidar and optical, sea ice field measurements, millimeter waves, advanced spectroscopy, spatial analysis and data compression, SAR polarimetry techniques. Also discussed are: plant canopy modeling, optical RS techniques, optical and IR oceanography, soil moisture, sea ice back scattering, lightning cloud measurements, spatial textural analysis, SAR systems and techniques, active microwave sensing, lidar and optical, radar scatterometry, RS of estuaries, vegetation modeling, RS systems, EOS/SAR Alaska, applications for developing countries, SAR speckle and texture.

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