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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Design and building of two unique components for solar heating (1. flatplate solar collector using no metal components, and 2. solar powered pump for heating and cooling systems are outlined in report. Report also discusses hardware, deliverable end items, problems encountered during fabrication and testing, and performance certification.
Post-irradiation effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current MIL-STD Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si).
Select computer codes developed over the years to simulate specific aspects of engine structures are described. These codes include blade impact integrated multidisciplinary analysis and optimization, progressive structural fracture, quantification of uncertainties for structural reliability and risk, benefits estimation of new technology insertion and hierarchical simulation of engine structures made from metal matrix and ceramic matrix composites. Collectively these codes constitute a unique infrastructure readiness to credibly evaluate new and future engine structural concepts throughout the development cycle from initial concept, to design and fabrication, to service performance and maintenance and repairs, and to retirement for cause and even to possible recycling. Stated differently, they provide 'virtual' concurrent engineering for engine structures total-life-cycle-cost.
Instead of bulky coils and compressors used in conventional refrigeration systems, UST design engineers drew on thermo-electric technology. UST's precision temperature chambers (PTC's) feature small thermoelectric modules that measure not much more than 1 square inch and operate on unique phenomenon of heat exchange. When electric current flows through specialized metallic crystals, heat is produced; when current direction is reversed cooling is produced.
The conservation of weight and space are major challenges for launch vehicles, especially upper stages. Upper-stage launch vehicles are confined by the space of the payload fairing of the first stage and it is difficult to stack fuel and oxidizer tanks end-to-end. Toroidal tanks have been studied as a way to help solve this problem. A toroidal tank concept would allow a portion of another tank, or part of an engine, to pass through its center opening. A toroidal tank assembly would be especially beneficial if it could somehow handle structural loads of the vehicle. Marshall Space Flight Center, along with ATK Thiokol Propulsion, is designing and fabricating a toroidal tank composed of individual conformal segments. Each conformal segment will be a metal-lined composite over-wrapped vessel. This paper will demonstrate unique materials and processing approaches that are overcoming hurdles for the fabrication of this vessel.
A weld is made when two pieces of metal are united or fused together using heat or pressure, and sometimes both. There are several different types of welds, each having their own unique properties and microstructure. Strength is a property normally used in deciding which kind of weld is suitable for a certain metal or joint. Depending on the weld process used and the heat required for that process, the weld and the heat-affected zone undergo microstructural changes resulting in stronger or weaker areas. The heat-affected zone (HAZ) is the region that has experienced enough heat to cause solid-state microstructural changes, but not enough to melt the material. This area is located between the parent material and the weld, with the grain structure growing as it progresses respectively. The optimal weld would have a short HAZ and a small fluctuation in strength from parent metal to weld. To determine the strength of the weld and decide whether it is suitable for the specific joint certain properties are looked at, among these are ultimate tensile strength, 0.2% offset yield strength and hardness. Ultimate tensile strength gives the maximum load the metal can stand while the offset yield strength gives the amount of stress the metal can take before it is 0.2% longer than it was originally. Both of these are good tests, but they both require breaking or deforming the sample in some way. Hardness testing, however, provides an objective evaluation of weld strengths, and also the difference or variation in strength across the weld and HAZ which is difficult to do with tensile testing. Hardness is the resistance to permanent or plastic deformation and can be taken at any desired point on the specimen. With hardness testing, it is possible to test from parent metal to weld and see the difference in strength as you progress from parent material to weld. Hardness around grain boundaries and flaws in the material will show how these affect the strength of the metal while still retaining the sample. This makes hardness testing a good test for identifying grain size and microstructure.
A technique for improving high temperature evaporation-condensation heat-transfer devices which have important and unique advantage in terrestrial and space energy processing is described. The device is in the form of a heat pipe comprising a sealed container or envelope which contains a capillary wick. The temperature of one end of the heat pipe is raised by the input of heat from an external heat source which is extremely hot and corrosive. A working fluid of a corrosive alkali metal, such as lithium, sodium, or potassium transfers this heat to a heat receiver remote from the heat source. The container and wick are fabricated from a superalloy containing a small percentage of a corrosion inhibiting or gettering element. Lanthanum, scandium, yttrium, thorium, and hafnium are utilized as the alloying metal.
A comparative study was conducted of the metal composition of 34 pallasites in order to shed further light on the origin of these meteorites. Concentrations of Au, As, Co, Ga, Ge, Ir, Ni, and W in pallasitic metal were determined. Most pallasites are found to have similar compositions indicating a close genetic relationship, and are designated as main group. The Eagle Station Trio is unrelated to the main group as indicated by higher Ni, Ge, and Ir and lower As, Au, and Ga contents in the metal, and olivine richer in Fe and Sc and poorer in Mg and Mn. The trio of Springwater, Rawlinna and Phillips County have metal compositions appropriate to high-Ni main group members, but their fayalite contents suggest they are not closely related to it. Pavlodar and Glorieta Mountain appear to be unique pallasites, and Brenham an anomalous main group member. Krasnoyarsk is classified as a main group member. Main group pallasites have metal compositions which overlap those of IIIAB iron meteorites on a Ga-Ge plot, and they have similar Au, As, Cr, Ir, Ni and W contents to high-Ni IIIAB irons.
Dusty hyperluminous galaxies in the early universe provide unique environments for studying the role of massive stars in the formation and destruction of dust. At redshifts above approx. 6, when the universe was less than approx. 1 Gyr old, dust could have only condensed in the explosive ejecta of Type-II supernovae (SNe), since most of the progenitors of the AGB stars, the major alternative source of interstellar dust, did not have time to evolve off the main sequence. I will present analytical models for the evolution of the gas, dust, and metals in high redshift galaxies, with a special application to SDSS J1148+5251, a hyperluminous quasar at $z = 6.4$. I will also discuss possible star formation scenarios consistent with observational constraints on the dust and gas content of this object.
If the measured Os isotopic ratios are a signature from the Earth's outer core, understanding them is a unique opportunity to understand more about the Earth's core. The distribution of elements between the Earth's solid inner core and the liquid outer core will depend on their solid metal-liquid metal partition coefficients (D). Solid metal-liquid metal partitioning data are loosely consistent with the needed fractionations between Re-Os and Pt-Os to account for the Os isotopic signature; D(Os) is greater than both D(Re) and D(Pt), and the magnitude of the partition coefficients are similar to those needed [e.g. 7, 8]. The pressure in the core, the composition of the core, and the crystal structure of the solid Fe alloy in the inner core may influence the specific values of the partition coefficients. It may thus be possible to use these sensitivities of the partition coefficients to gain insight into the conditions within the Earth's core. In this abstract, we focus on the compositional influence of C, a potential component of the light element in the Earth's core [9], on the partitioning behaviors of Pt, Re, and Os.
NRC-2 Superinsulation, manufactured by Metallized Products, Inc. (MPI), is designed for superconducting magnets used in MRI systems and particle accelerators. It is a thin, polyester film characterized by a unique crinkled surface that provides surface stand-off between layers and minimizes heat transfer in multilayer applications. NRC-2/Two is a two-sided metallized film. The material, originally developed as a skin for balloon-like satellites, was later used by NASA as a thermal barrier. MPI worked with NASA on the development of the original material and now supplies it for both space and consumer applications.
Survey reviews the structural applications of refractory metals and the special problems they present in manufacture, evaluation, and application. The unique facilities required for their processing and evaluation, a summary of accomplishments in achieving commercial products, and the present status of the most advanced refractory materials are presented.
A cylindrical shell skirt structure 4.57 m (180 in.) in diameter and 3.66 m (144 in.) high was subjected to a design and analysis study using a wide variety of structural materials and concepts. The design loading of 1225.8 N/cm (700 lb/in.) axial compression and 245.2 N/cm (140 lb/in.) torsion is representative of that expected on a typical space tug skirt section. Structural concepts evaluated included honeycomb sandwich, truss, isogrid, and skin/stringer/frame. The materials considered included a wide variety of structural metals as well as glass, graphite, and boron-reinforced composites. The most unique characteristic of the candidate designs is that they involve the use of very thin-gage material. Fabrication and structural test of small panels and components representative of many of the candidate designs served to demonstrate proposed fabrication techniques and to verify design and analysis methods.
Flat plate (vapor chamber) heat pipes were made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3 to 5 C over the panel surface.
It has been recognized from the onset that high temperature superconductivity held great promise for major advances across a broad range of NASA interests. The current effort is organized around four key areas: communications and data, sensors and cryogenics, propulsion and power, and space materials technology. Recently, laser ablated YBa2Cu3O(7-x) films on LaAIO produced far superior RF characteristics when compared to metallic films on the same substrate. This achievement has enabled a number of unique microwave device applications, such as low insertion loss phase shifters and high Q filters. Melt texturing and melt quenched techniques are being used to produce bulk materials with optimized magnetic properties. These yttrium enriched materials possess enhanced flux pinning characteristics and will lead to prototype cryocooler bearings. Significant progress has also occurred in bolometer and current lead technology. Studies are being conducted to evaluate the effect of high temperature superconducting materials on the performance and life of high power magneto-plasma-dynamic thrusters. Extended studies were also performed to evaluate the benefit of superconducting magnetic energy storage for LEO space station, lunar and Mars mission applications. The project direction and level of effort of the program are also described.
Current research in the area of high temperature superconductivity is organized around four key areas: communications and data, sensors and cryogenics, propulsion and power, and space materials technology. Recently, laser ablated YBa2Cu3O(7-x) films on LaAlO3 produced far superior RF characteristics when compared to metallic films on the same substrate. The achievement has enabled a number of unique microwave device applications, such as low insertion loss phase shifters and high-Q filters. Melt texturing and melt-quenched techniques are being used to produce bulk material with optimized magnetic properties. These yttrium-enriched materials possess enhanced flux pinning characteristics and could lead to prototype cryocooler bearings. Significant progress has also occurred in bolometer and current lead technology. Studies were conducted to evaluate the effect of high temperature superconducting materials on the performance and life of high power magnetoplasma-dynamic thrusters. Extended studies were also performed to evaluate the benefit of superconducting magnetic energy storage for LEO space station, lunar, and Mars mission applications.
This system was developed by the Sensors 2000! Program (S2K!) at Ames Research Center for the E132 STS-90 Neurolab Shuttle mission experiment to monitor 12 untethered adult male rats housed in the Research Animal Habitat Facility (RAHF). The system monitored the animals for body temperature, heart rate, and activity, and stored the data on board for up to 21 days for downloading after landing. The principal investigator's monitoring requirements were accomplished integrating a combination of both commercial and in-house developed hardware and software, including an off-the-shelf implantable telemetry transmitter and receiver system. In addition, a custom-developed antenna system was incorporated into the RAHF cages to perform the unique function of near-field radio-frequency (rf) measurement in the metal cages. This system proved the ability to perform wireless physiological measurements in very non-ideal circumstances using existing habitats and cabling without interfering with other experiment or shuttle systems. S2K! is continuing development on a custom telemetry transmitter and receiver system which will expand measurement capabilities.
A safe, non-invasive method for forming images through clothing of large groups of people, in order to search for concealed weapons either made of metal or not, has been developed. A millimeter wavelength scanner designed in a unique, ring-shaped configuration can obtain a full 360 image of the body with a resolution of less than a millimeter in only a few seconds. Millimeter waves readily penetrate normal clothing, but are highly reflected by the human body and concealed objects. Millimeter wave signals are nonionizing and are harmless to human tissues when used at low power levels. The imager (see figure) consists of a thin base that supports a small-diameter vertical post about 7 ft (=2.13 m) tall. Attached to the post is a square-shaped ring 2 in. (=5 cm) wide and 3 ft (=91 cm) on a side. The ring is oriented horizontally, and is supported halfway along one side by a connection to a linear bearing on the vertical post. A planar RF circuit board is mounted to the inside of each side of the ring. Each circuit board contains an array of 30 receivers, one transmitter, and digitization electronics. Each array element has a printed-circuit patch antenna coupled to a pair of mixers by a 90 coupler. The mixers receive a reference local oscillator signal to a subharmonic of the transmitter frequency. A single local oscillator line feeds all 30 receivers on the board. The resulting MHz IF signals are amplified and carried to the edge of the board where they are demodulated and digitized. The transmitted signal is derived from the local oscillator at a frequency offset determined by a crystal oscillator. One antenna centrally located on each side of the square ring provides the source illumination power. The total transmitted power is less than 100 mW, resulting in an exposure level that is completely safe to humans. The output signals from all four circuit boards are fed via serial connection to a data processing computer. The computer processes the approximately 1-MB data set into a three-dimensional image in a matter of seconds. The innovation is to configure the receiver array in a ring topology surrounding the scanned object. The ring is then scanned vertically to cover the necessary two-dimensional surface. This fabrication of the ring is made possible by using planar antenna and circuit technology. A planar circuit board serves as a medium for both antennas and signal processing components. Using this technique, parts counts are kept low, and the cost per element is a small fraction of a waveguide-based system.