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100 kHz core loss properties of sample transverse magnetically annealed, cobalt-based amorphous and iron-based nanocrystalline tape wound magnetic cores are presented over the temperature range of -150 C to 150 C, at selected values of Bpeak. For B-fields not close to saturation, the core loss is not sensitive to temperature in this range and is as low as seen in the best MnZn power ferrites at their optimum temperatures. Frequency resolved characteristics are given over the range of 50 kHz to 1 MHz, but at Bpeak = 0.1 T and 50 C only. For example, the 100 kHz specific core loss ranged from 50 mW/cm3 to 70 mW/cm3 for the 3 materials, when measured at 0.1 T and 50 C. This very low high frequency core loss, together with near zero saturation magnetostriction and insensitivity to rough handling, makes these amorphous ribbons strong candidates for power magnetics applications in wide temperature aerospace environments

Spacecraft radiators reject heat to their surroundings. Radiators can be deployable or mounted on the body of the spacecraft. NASA's Crew Exploration Vehicle is to use body mounted radiators. Coatings play an important role in heat rejection. The coatings provide the radiator surface with the desired optical properties of low solar absorptance and high infrared emittance. These specialized surfaces are applied to the radiator panel in a number of ways, including conventional spraying, plasma spraying, or as an appliqué. Not specifically designed for a weathering environment, little is known about the durability of conventional paints, coatings, and appliqués upon exposure to weathering and subsequent exposure to solar wind and ultraviolet radiation exposure. In addition to maintaining their desired optical properties, the coatings must also continue to adhere to the underlying radiator panel.

The airworthiness authorities (FAA, JAA, Transport Canada) will be releasing a draft rule in the 2006 timeframe concerning the operation of aircraft in a Supercooled Large Droplet (SLD) environment aloft. The draft rule will require aircraft manufacturers to demonstrate that their aircraft can operate safely in an SLD environment for a period of time to facilitate a safe exit from the condition. It is anticipated that aircraft manufacturers will require a capability to demonstrate compliance with this rule via experimental means (icing tunnels or tankers) and by analytical means (ice prediction codes). Since existing icing research facilities and analytical codes were not developed to account for SLD conditions, current engineering tools are not adequate to support compliance activities in SLD conditions. Therefore, existing capabilities need to be augmented to include SLD conditions.

The thick oxide layer of silicon-on-insulator (SOI) devices significantly reduces the junction leakage current at elevated temperatures compared to similar Si devices, resulting in an elevated maximum operating temperature. The maximum operating temperature, specified by manufacturers, of commercial SOI devices/circuits with conventional packaging is usually 225°C. It is important to understand the performance and de-ratings of these SOI circuits at temperatures above 225°C without the temperature limit imposed by commercial packaging technology. This work tested a low frequency square-wave oscillator based on an SOI 555 Timer with a special high temperature ceramic packaging technology from room temperature to 375°C. The timer die was attached to a 96% aluminum oxide substrate with high temperature durable gold (Au) thick-film metallization, and interconnected with Au wires.

Oxygen storage and delivery systems for advanced Lunar Exploration Missions are substantially different than those of the International Space Station (ISS) or Apollo missions. The oxygen must be stored without venting for durations of 180 to 210 days prior to use and then used to supply both the steady, low pressure oxygen for the crew, and the higher-pressure oxygen for the extra-vehicular mobility unit. The baseline design is a high pressure gaseous oxygen storage system. Alternate technologies that may offer substantial advantages in terms of the equivalent system mass over the baseline design are being currently evaluated. This study examines both the supercritical and subcritical liquid oxygen storage options, including one with active cooling using a cryocooler. It is found that an actively cooled sub-critical storage system offered the lowest mass system that could satisfy the requirements.

The Icing Research Tunnel at NASA Glenn follows the recommended practice for calibration outlined in SAE’s ARP5905. The calibration team has followed the schedule of a full calibration every five years with a check calibration done every six months following. The liquid water content of the IRT has maintained stability within the stated specifications of variation within +/- 10% of the curve fit equation generated from calibration data. Using past measurements and data trends, IRT characterization engineers wanted to develop methods for the ability to know when data were not within variation. Trends can be observed in the liquid water content measurement process by constructing statistical process control charts. This paper describes data processing procedures for the Multi-Element Sensor in the IRT, including collision efficiency corrections, canonical correlation analysis, process for rejection of data, and construction of control charts.

This paper presents results from a smoke detection experiment entitled Smoke Aerosol Measurement Experiment (SAME) which was conducted in the Microgravity Science Glovebox on the International Space Station (ISS) during Expedition 15. Five different materials representative of those found in spacecraft were pyrolyzed at temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow conditions. The sample materials were Teflon®, Kapton®, cellulose, silicone rubber and dibutylphthalate. The transport time from the smoke source to the detector was simulated by holding the smoke in an aging chamber for times ranging from 10 to1800 seconds. Smoke particle samples were collected on Transmission Electron Microscope (TEM) grids for post-flight analysis.

The problem of determining equilibrium temperatures for re-radiating surfaces in space vacuum was analyzed and the resulting mathematical relationships were incorporated in a code to determine space sink temperatures in the solar system. A brief treatment of planetary atmospheres is also included. Temperature values obtained with the code are in good agreement with available spacecraft telemetry and meteorological measurements for Venus and Earth. The code has been used in the design of space power system radiators for future interplanetary missions.

Development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (Ni-H2) program at the NASA Glenn Research Center. The approach has been to improve the nickel electrode by continuing combined in-house and contract efforts to develop a lighter weight electrode for the nickel-hydrogen cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. These plaques are commercial products and have an advantage of increased surface area available for the deposition of active material. Initial tests include activation and capacity measurements at five different discharge levels, C/2, 1.0C, 1.37C, 2.0C, and 2.74C. The electrodes are life cycle tested using a half-cell configuration at 40 and 80% depths-of-discharge (DOD) in a low-Earth-orbit regime. The electrodes that pass the initial tests are life cycle-tested in a boilerplate nickel-hydrogen cell before flightweight designs are built and tested.

Unmanned aerial vehicles (UAVs) are currently under development for NASA missions, earth sciences, aeronautics, the military, and commercial applications. The design of an all electric power and propulsion system for small UAVs was the focus of a detailed study. Currently, many of these small vehicles are powered by primary (nonrechargeable) lithium-based batteries. While this type of battery is capable of satisfying some of the mission needs, a secondary (rechargeable) battery power supply system that can provide the same functionality as the current system at the same or lower system mass and volume is desired. A study of commercially available secondary battery cell technologies that could provide the desired performance characteristics was performed.

An experiment was conducted in the Icing Research Tunnel (IRT) at NASA Glenn Research Center to study the effect of sweep angle and temperature on the formation of ice accretions on a NACA 0012 swept wing at SLD conditions. From a baseline Appendix-C condition with a MVD of 20m the drop size was changed to 110 and 200m for the SLD cases. Casting data, ice shape tracings, time-sequence and photographic data were obtained. Time-sequence photography was taken during each run to capture in real time the formation of the ice accretion. Measurements of the critical distance were obtained.

Manufacturing readiness of composite rotors and certification of flywheels depend in part on the maturity of nondestructive evaluation (NDE) technology for process optimization and quality assurance, respectively. Capabilities and limitations of x-ray-computed tomography and radiography, as well as advanced ultrasonics were established on NDE ring and rotor standards with EDM notches and drilled holes. Also, intentionally seeded delamination, tow break, and insert of bagging material were introduced in hydroburst-rings to study the NDE detection capabilities of such anomalies and their effect on the damage tolerance and safe life margins of subscale rings and rotors. Examples of possible occurring flaws or anomalies in composite rings as detected by NDE and validated by destructive metallography are shown. The general NDE approach to ensure quality of composite rotors and to help in the certification of flywheels is briefly outlined.

The on-demand production of Medical Grade Water (MGW) is a critical biomedical requirement for future long-duration exploration missions. Potentially, large volumes of MGW may be needed to treat burn victims, with lesser amounts required to reconstitute pharmacological agents for medical preparations and biological experiments, and to formulate parenteral fluids during medical treatment. Storage of MGW is an untenable means to meet this requirement, as are nominal MGW production methods, which use a complex set of processes to remove chemical contaminants, inactivate all microorganisms, and eliminate endotoxins, a toxin originating from gram-negative bacteria cell walls. An innovative microgravity compatible alternative, using a microwave-based MGW generator, is described in this paper. The MGW generator efficiently couples microwaves to a single-phase flowing stream, resulting in super-autoclave temperatures.

NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated", these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development.

This paper presents the results of research efforts performed to evaluate the performance of rechargeable battery management technologies at low temperatures. Three battery chemistries are considered in this work. These are the Nickel-Cadmium (NiCd), Nickel-Metal Hydride (NiMH) and Lithium-ion (Li-ion). Battery management evaluation kits from two battery manufacturers were acquired and tested. These are the DS2434k, DS2435k and DS2437k from Dallas Semiconductor and the MAX712, MAX846A and MAX2003A from MAXIM Integrated Products. The kits were characterized in a chamber whose temperature was changed and regulated using liquid nitrogen. The temperature of the chamber was varied from 20°C to −180°C. At each temperature, the battery voltage, current, state of charge, temperature and other auxiliary variables as monitored by each chip were recorded. Also, the performance of each kit after a complete cooling and heating cycle is recorded.

Using a new fiber electrode technology, currently developed and produced by Bekaert Corporation (Bekaert), Electro Energy, Inc., (EEI) Mobile Energy Products Group (formerly, Eagle-Picher Technologies, LLC, Power Systems Department) in Colorado Springs, CO has demonstrated that it is feasible to manufacture flight weight nickel hydrogen cells having about twice the specific energy (80 vs. 40 watt-hr./kg) as state-of-the-art nickel hydrogen cells that are currently flown on geosynchronous communications satellites. Although lithium-ion battery technology has made large in-roads to replace the nickel alkaline technology (nickel-cadmium, nickel-metal hydride), the technology offered here competes with lithium-ion weight and offers alternatives not present in the lithium-ion chemistry such as: ability to undergo a continuous overcharge, reversal on discharge, and sustain rate capability sufficient to start automotive and aircraft engines at subzero temperatures.

A process of using machine learning to segment impact ice microstructure is presented and analyzed. The microstructure of impact ice has been shown to correlate with the adhesion strength of ice. Machine vision techniques are explored as a method of decreasing analysis time. The segmentation was conducted with the goal of obtaining average grain size estimations. The model was trained on a set of micrographs of impact ice grown at NASA Glenn’s Icing Research Tunnel. The model leveraged a model pre-trained on a large set of micrographs of various materials as a starting point. Post-processing of the segmented images was done to connect broken boundaries. An automatic method of determining grain size following an ASTM standard was implemented. Segmentation results using different training sets as well as different encoder and decoder pairs are presented. Calculated sizes are compared to manual grain size measurement methods.

An experiment was conducted in the Icing Research Tunnel (IRT) at NASA Glenn Research Center to obtain castings of ice accretions formed on a 28° swept GLC-305 airfoil that is representative of a modern business aircraft wing. Because of the complexity of the casting process, the airfoil was designed with three removable leading edges covering the whole span. Ice accretions were obtained at six icing conditions. After the ice was accreted, the leading edges were detached from the airfoil and moved to a cold room. Molds of the ice accretions were obtained, and from them, urethane castings were fabricated. This experiment is the icing test of a two-part experiment to study the aerodynamic effects of ice accretions.

Packed bed reactors are well known for their vast and diverse applications in the chemical industry; from gas absorption, to stripping, to catalytic conversion. Use of this type of reactor in terrestrial applications has been rather extensive because of their simplicity and relative ease of operation. Developing similar reactors for use in microgravity is critical to many space-based advanced life support systems. However, the hydrodynamics of two-phase flow packed bed reactors in this new environment and the effects of one physicochemical process on another has not been adequately assessed. Surface tension or capillary forces play a much greater role which results in a shifting in flow regime transitions and pressure drop. Results from low gravity experiments related to flow regimes and two-phase pressure drop models are presented in this paper along with a description of plans for a flight experiment on the International Space Station (ISS).

Supercritical water oxidation (SCWO) may become an attractive technology for processing solid and liquid wastes for long duration space and extraterrestrial planetary missions. Gravitational influences on the operation of SCWO reactors are discussed in the context of key dimensionless parameters for two general modes of operation: a “premixed” mode, where the reactants are brought to supercritical temperatures and pressures simultaneously, and a “diffusion limited” mode, where one of the reactants (typically the oxidizer) is injected into the reactor after the bulk fluid is raised to supercritical temperatures and pressures. An experimental facility for testing the gravitational influences on a SCWO reactor is then discussed.