Evaporative Cooling Garment System /ECGS/, part 1 Final report
Evaporative Cooling Garment System /ECGS/ for body cooling during extravehicular activity in space
Bitterly, J. G.↗
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Evaporative Cooling Garment System /ECGS/, part 2 Final report
Evaporative Cooling Garment System /ECGS/ for body cooling during extravehicular activity in space - typical design verification test run
Bitterly, J. G.↗
Joining techniques for fabrication of composite air-cooled turbine blades and vanes
Air cooled turbine blades activated diffusion brazing and gas pressure welding, using composite finned configuration model
Berry, T. F.↗
Ultraviolet and optical spectrum studies of Lambda Andromedae - Evidence for atmospheric inhomogeneities
To pursue the study of solar phenomena in cool stars, chromospheric activity in Lambda Andromedae (HD 222107 has been investigated). This binary, whose primary star is G7-G8 IV-III, shows strong chromospheric emissions and is related to the RS CVn-type systems. The first quantitative measurements of chromospheric and solar-type transition-region emissions as a function of the variable starspot and active-region phenomena in an RS CVn star are presented. The presence of optically darker starspots in Lambda And coincides with the brightening of both Ca II K emission and the ultraviolet transition-region lines. The ultraviolet and optical spectra show attributes of starspots, active regions, and mass flow. Analogies to solar activity are successful in explaining these observations.
Baliunas, S. L.↗
Mixed time integration schemes for transient conduction forced-convection analysis
A partition procedure for forced-convection conduction transient problems is presented. Mixed time partitions are defined wherein coupled conduction force-matrix equations are discretized using an implicit integration method, followed by derivation of a mixed time integration technique. Explicit-implicit and explicit-explicit partitions are performed for a stability analysis for transient conditions, e.g., those found in an actively air-cooled engine and airframe structure.
Liu, W. K.↗
Stellar activity cycles
The variety of stellar chromospheric and coronal activity provides a framework for understanding solar and stellar magnetic activity. It is pointed out that the recognition of an 11-yr periodicity within the record of sunspot numbers is a relatively recent discovery of just over a century ago. The solar activity cycle is examined, taking into account the sunspot cycle, and solar dynamo models. Time-averaged stellar chromospheric activity levels are considered along with long-term activity fluctuations of cool stars. Attention is given to the direct measurement of stellar magnetic fields, solar luminosity variations, the RS Canum Venaticorum and BY Draconis variables, continuum variations in lower main sequence stars, chromospheric variations in lower main sequence stars, and chromospheric variations in evolved stars.
Baliunas, S. L.↗
Economy of middeck payloads
The utilization of the middeck, designed as the crew quarters, for experiments is examined. The dimensions of the middeck's standard lockers, double lockers, adapter plates, and the galley, which are applicable for experiments, are described. The utilities available for middeck payloads include ac and dc electrical power supply, active and passive cooling, vacuum/vent line connections, and data handling, and four basic payload configurations are possible. The development of a middeck accommodations rack to make payload space more flexible and to enable an optimum number and variety of experiments to be flown is proposed. Diagrams of the orbiter's middeck and experimental designs are provided.
Michel, E. L.↗
Hypersonic structures and materials - A progress report
The weight of a hypersonic, airbreathing SSTO vehicle may be more critical than for any previous aerospacecraft; an evaluation is accordingly made of the development status and applicability of intermetallic compounds, metal-matrix composites, carbon-carbon composites, ceramics, and ceramic-matrix composites applicable to SSTO craft primary structures. Aerothermal, aerothermoelastic, and acoustic loads are high because the airbreathing SSTO vehicle must follow a high dynamic pressure trajectory in order to achieve the requisite propulsive efficiency. Attention is given to the prospects for integral cryogenic tankage and actively hydrogen-cooled airframe and engine structures.
Jackson, L. Robert↗
Electron scattering and the distances to cluster cooling flows
Cluster cooling flows have electron-scattering optical depths which are estimated to be about 0.01. Many of the cluster-dominant galaxies centered in cluster cooling flows have active nuclei, and about 1 percent of the luminosity from the active nuclei should appear as diffuse, scattered radiation. It is shown here that detection of this scattered radiation at radio wavelengths can provide a measure of the distance to the cluster that is independent of the Hubble constant. Observations of the scattered surface brightness profile can also be used to test for clumpiness in the gas, for variations in the central radio source on time scales less than 100,000 yr, and for the degree of beaming of radiation from the central source.
Wise, Michael W.↗
Cryogenic Propellant Long-term Storage With Zero Boil-off
Significant boil-off losses of cryogenic propellant storage systems in long-duration space mission applications result in additional propellant and large tanks. The zero boil-off (ZBO) concept consists of an active cryo-cooling system integrated with traditional passive thermal insulation. The potential mass reductions with the ZBO concept are Substantial; therefore, further exploration through technology programs has been initiated within NASA. A large-scale demonstration of the ZBO concept has been devised utilizing the Marshall Space Flight Center (MSFC) Multipurpose Hydrogen Test Bed (MHTB) along with a cryo-cooler unit. The cryo-cooler with the MHTB and spraybar recirculation/mixer system in a manner that enables thermal energy removal at a rate that equals the total tank heat leak. The liquid hydrogen is withdrawn from the tank, passed through a heat exchanger, and then the chilled liquid is sprayed back into the tank through a spraybar. The test series will be performed over a 30-40 day period. Tests will be conducted at multiple fill levels and various mixer operational cycles to demonstrate concept viability and to provide benchmark data to be used in analytical model development. In this paper. analytical models for heat flows through the MHTB tank, cryo-cooler performance. and spraybar performance will be presented.
Hedayat, A.↗
Cryogenic Propellant Long-Term Storage With Zero Boil-Off
Significant boil-off losses from cryogenic propellant storage systems in long-duration space mission applications result in additional propellant and larger tanks. The potential propellant mass loss reductions with the Zero Boil-off (ZBO) concept are substantial; therefore, further exploration through technology programs has been initiated within NASA. A large-scale demonstration of the ZBO concept has been devised utilizing the Marshall Space Flight Center (MSFC) Multipurpose Hydrogen Test Bed (MHTB) along with a cryo-cooler unit. The ZBO concept consists of an active cryo-cooling system integrated with traditional passive thermal insulation. The cryo-cooler is interfaced with the MHTB and spraybar recirculation/mixer system in a manner that enables thermal energy removal at a rate that equals the total tank heat leak. The liquid hydrogen (LH2) is withdrawn from the tank, passed through a heat exchanger, and then the chilled liquid is sprayed back into the tank through a spraybar. The test series will be performed over a 20-30 day period. Tests will be conducted at multiple fill levels to demonstrate concept viability and to provide benchmark data to be used in analytical model development. In this paper the test set-up and test procedures are presented.
Hedayat, Ali↗
Constraints on the Opening Rate of Bands on Europa
The opening rates of two bands on Europa, inferred to be sites of spreading of the icy lithosphere, are constrained based on a mid-ocean ridge analog model. Estimates of brittle-ductile transition depth combined with a conductive cooling model limit active band lifetimes to 0.24 - 35 Myr and strain rates of 8.1 x 10(exp -13) - 8.2 x 10(exp -15)/s. These values suggest tensile strengths for ice on Europa of 0.46 - 2.3 MPa, consistent with nonsynchronous rotation as the dominant driving mechanism for band opening.
Stempel, M. M.↗
On the Development of a Unique Arc Jet Test Apparatus for Control Surface Seal Evaluations
NASA Glenn has developed a unique test apparatus capable of evaluating control surface seal and flap designs under simulated reentry heating conditions in NASA Johnson's arc jet test facility. The test apparatus is capable of testing a variety of seal designs with a variety of control surface materials and designs using modular components. The flap angle can be varied during testing, allowing modification of the seal environment while testing is in progress. The flap angle is varied using an innovative transmission system which limits heat transfer from the hot flap structure to the motor, all while keeping the components properly aligned regardless of thermal expansion. A combination of active and passive cooling is employed to prevent thermal damage to the test fixture while still obtaining the target seal temperature.
Finkbeiner, Joshua R.↗
Gas turbine engine active clearance control
Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.
Deveau, Paul J.↗
Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance
Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.
Fisher, John W.↗
NASA Tech Briefs, August 2005
Topics include: Hidden Identification on Parts: Magnetic Machine-Readable Matrix Symbols; System for Processing Coded OFDM Under Doppler and Fading; Multipurpose Hyperspectral Imaging System; Magnetic-Flux-Compensated Voltage Divider; High-Performance Satellite/Terrestrial-Network Gateway; Internet-Based System for Voice Communication With the ISS; Stripline/Microstrip Transition in Multilayer Circuit Board; Dual-Band Feed for a Microwave Reflector Antenna; Quadratic Programming for Allocating Control Effort; Range Process Simulation Tool; Simulator of Space Communication Networks; Computing Q-D Relationships for Storage of Rocket Fuels; Contour Error Map Algorithm; Portfolio Analysis Tool; Glass Frit Filters for Collecting Metal Oxide Nanoparticles; Anhydrous Proton-Conducting Membranes for Fuel Cells; Portable Electron-Beam Free-Form Fabrication System; Miniature Laboratory for Detecting Sparse Biomolecules; Multicompartment Liquid-Cooling/Warming Protective Garments; Laser Metrology for an Optical-Path-Length Modulator; PCM Passive Cooling System Containing Active Subsystems; Automated Electrostatics Environmental Chamber; Estimating Aeroheating of a 3D Body Using a 2D Flow Solver; Artificial Immune System for Recognizing Patterns; Computing the Thermodynamic State of a Cryogenic Fluid; Safety and Mission Assurance Performance Metric; Magnetic Control of Concentration Gradient in Microgravity; Avionics for a Small Robotic Inspection Spacecraft; and Simulation of Dynamics of a Flexible Miniature Airplane.
Source record↗
Folding Elastic Thermal Surface - FETS
The FETS is a light and compact thermal surface (sun shade, IR thermal shield, cover, and/or deployable radiator) that is mounted on a set of offset tape-spring hinges. The thermal surface is constrained during launch and activated in space by a thermomechanical latch such as a wax actuator. An application-specific embodiment of this technology developed for the MATMOS (Mars Atmospheric Trace Molecule Occultation Spectrometer) project serves as a deployable cover and thermal shield for its passive cooler. The FETS fits compactly against the instrument within the constrained launch envelope, and then unfolds into a larger area once in space. In this application, the FETS protects the passive cooler from thermal damage and contamination during ground operations, launch, and during orbit insertion. Once unfolded or deployed, the FETS serves as a heat shield, intercepting parasitic heat loads by blocking the passive cooler s view of the warm spacecraft. The technology significantly enhances the capabilities of instruments requiring either active or passive cooling of optical detectors. This can be particularly important for instruments where performance is limited by the available radiator area. Examples would be IR optical instruments on CubeSATs or those launched as hosted payloads because radiator area is limited and views are often undesirable. As a deployable radiator, the panels making up the FETS are linked thermally by thermal straps and heat pipes; the structural support and deployment energy is provided using tape-spring hinges. The FETS is a novel combination of existing technologies. Prior art for deployable heat shields uses rotating hinges that typically must be lubricated to avoid cold welding or static friction. By using tape-spring hinges, the FETS avoids the need for lubricants by avoiding friction altogether. This also eliminates the potential for contamination of nearby cooled optics by outgassing lubricants. Furthermore, the tape-spring design of the FETS is also self-locking so the panels stay in a rigid and extended configuration after deployment. This unexpected benefit makes the tape-spring hinge design of the FETS a light, simple, reliable, compact, non-outgassing hinge, spring, and latch. While tape-spring hinges are not novel, they have never been used to deploy passive unfolding thermal surfaces (radiator panels, covers, sun shades, or IR thermal shields). Furthermore, because this technology is compact, it has minimal impact on the launch envelope and mass specifications. FETS enhances the performance of hosted payload instruments where the science data is limited by dark noise. Incorporating FETS into a thermal control system increases radiator area, which lowers the optical detector temperature. This results in higher SNR (signal-to-noise ratio) and improved science data.
Urquiza, Eugenio↗
Real-Time Closed Loop Modulated Turbine Cooling
It has been noted by industry that in addition to dramatic variations of temperature over a given blade surface, blade-to-blade variations also exist despite identical design. These variations result from manufacturing variations, uneven wear and deposition over the life of the part as well as limitations in the uniformity of coolant distribution in the baseline cooling design. It is proposed to combine recent advances in optical sensing, actuation, and film cooling concepts to develop a workable active, closed-loop modulated turbine cooling system to improve by 10 to 20 the turbine thermal state over the flight mission, to improve engine life and to dramatically reduce turbine cooling air usage and aircraft fuel burn. A reduction in oxides of nitrogen (NOx) can also be achieved by using the excess coolant to improve mixing in the combustor especially for rotorcraft engines. Recent patents filed by industry and universities relate to modulating endwall cooling using valves. These schemes are complex, add weight and are limited to the endwalls. The novelty of the proposed approach is twofold 1) Fluidic diverters that have no moving parts are used to modulate cooling and can operate under a wide range of conditions and environments. 2) Real-time optical sensing to map the thermal state of the turbine has never been attempted in realistic engine conditions.
turbines↗