| Cell and Molecular Biology of Ataxia Telangiectasia Heterozygous Human Mammary Epithelial Cells Irradiated in Culture |
SEP 2002 |
24 pages |
| Authors:
Robert C. Richmond; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
 | The goal of this research is to define markers expressed in clinically normal human mammary epithelial cells (HMEC) such that a molecular epidemiological model of ionizing radiation-induced cancer may be considered. This approach has value since existing predictive models for radiogenic late effects have high uncertainty, and since tools of molecular biology have recently advanced such that molecular epidemiology is now a good investigative area for advancing predictive risk modeling. ... |
|
| National Environmental Change Information System Case Study |
NOV 2001 |
53 pages |
| Authors:
S. J. Goodman; R. Ritschard; M. G. Estes; U. Hatch; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The Global Hydrology and Climate Center and NASA's Marshall Space Flight Center conducted a fact-finding case study for the Data Management Working Group (DMWG) now referred to as the Data and Information Working Group (DIWG), of the U.S. Global Change Research Program (USGCRP) to determine the feasibility of an interagency National Environmental Change Information System (NECIS). In order to better understand the data and information needs of policy and decision ... |
|
| Cell and Molecular Biology of Ataxia Telangiectasia Heterozygous Human Mammary Epithelial Cells Irradiated in Culture |
SEP 2001 |
7 pages |
| Authors:
Robert C. Richmond; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Autologous isolates of cell types from obligate heterozygotes with the autosomal disorder ataxia-telangiectasia (A-T)were used to begin a tissue culture model for assessing pathways of radiation-induced cancer formation in this target tissue. This was done by establishing cultures of stromal fibroblasts and long-term growth human mammary epithelial cells (HMEC) in standard 2-dimensional tissue culture in order to establish expression of markers detailing early steps of carcinogenesis. The presumptive breast cancer ... |
|
| A New Technique for Achieving Impact Velocities. |
MAY 2001 |
|
| Authors:
A. J. Piekutowski; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
 | This report describes and presents the results of work that was done in an attempt to develop an augmented acceleration technique that would launch small projectiles of known shape, mass, and state to velocities of 10 km/sec and higher. The higher velocities were to be achieved by adding a third stage to a conventional two-stage, light-gas gun and using a modified firing cycle for the third stage. the technique did ... |
|
| Thermal Analysis of a Carbon Fiber Rope Barrier For Use in the Reusable Solid Rocket Motor Nozzle Joint-2 |
MAR 2001 |
9 pages |
| Authors:
J. L. Clayton; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This study provides development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the "open" assembly gap. Model development is based on a 1-D volume filling approach where ... |
|
| The 2000 NASA Aerospace Battery Workshop. |
MAR 2001 |
|
| Authors:
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This document contains the proceedings of the 33rd annual NASA Aerospace Battery Workshop, hosted by the Marshall Space Flight Center on November 14-16, 2000. The workshop was attended by scientists and engineers from various agencies of the U.S. Government, aerospace contractors, and battery manufacturers, as well as international participation in like kind from a number of countries around the world. The subjects covered included nickel-hydrogen, nickel-cadmium, lithium-ion, and silver-zinc technologies. ... |
|
| Behavior of a Round Cryogenic Jet at Below and Above the Critical Pressure |
1998 |
6 pages |
| Authors:
B. Chehroudi; D. Talley; E. Coy; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| In an effort to investigate and understand the behavior of the injected cryogenic fluid and its environment, a high pressure chamber is used into which pure N2 He, and O2 fluids are injected. Several chamber media are selected including, N2, Me, and mixtures of CO+N2. The effects of chamber pressure ranging from a subcritical to a supercritical values at a supercritical chamber are photographically observed and documented near the injector ... |
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| Study of Flow Pattern and Phase-Change Problem in Die Casting Process. |
29 JUN 1996 |
|
| Authors:
T. S. Wang; H. Wei; Y. S. Chen; H. M. Shang; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The flow pattern and solidification phenomena in die casting process have been investigated in the first phase study. The flow pattern is filling process is predicted by using a VOF (volume of fluid) method. A good agreement with experimental observation is obtained for filling the water into a die cavity with different gate geometry and with an obstacle in the cavity. An enthalpy method has been applied to solve the ... |
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| Design Considerations for Space Transfer Vehicles Using Solar Thermal Propulsion |
JUL 1995 |
8 pages |
| Authors:
William J. Emrich Jr.; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The economical deployment of satellites to high energy earth orbits is crucial to the ultimate success of this nation's commercial space ventures and is highly desirable for deep space planetary missions requiring earth escape trajectories. Upper stage space transfer vehicles needed to accomplish this task should ideally be simple, robust, and highly efficient. In this regard, solar thermal propulsion is particularly well suited to those missions where high thrust is ... |
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| Technology for the Stars: Extending Our Reach. Research and Technology Annual Report of the Marshall Space Flight Center Held in Alabama |
95 |
256 pages |
| Authors:
Harry Craft Jr; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Marshall Space Flight Center's greatest assets are its people highly qualified engineers and scientists who perform the daily analysis, development, and engineering necessary to extend humankind's grasp. Propulsion is the foundation that enables America's future in space. MSFC's talented team continues to achieve new advances through focused efforts in space propulsion, materials and processes, structures and dynamics, and avionics. Microgravity at MSFC provides invaluable insights into biotechnology processes and materials ... |
|
| Natural Orbital Environment Guidelines for Use in Aerospace Vehicle Development |
JUN 94 |
162 pages |
| Authors:
Robert E. Smith; B. J. Anderson; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This document provides definitions of the natural near-Earth space environment suitable for use in the initial development/design phase of any space vehicle. The natural environment includes the neutral atmosphere, plasma, charged particle radiation, electromagnetic radiation (EMR), meteoroids, orbital debris, magnetic field, physical and thermal constants, and gravitational field. Communications and other unmanned satellites operate in geosynchronous-Earth orbit (GEO); therefore, some data are given for GEO, but emphasis is on altitudes ... |
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| Hydrogen-Resistant Fe/Ni/Cr Base Superalloy |
1994 |
|
| Authors:
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A new fe-ni-base alloy has been studied. the alloy offers both high strength and resistance to hydrogen environment embrittlement. current composition, microstructure, and tensile properties in air and hydrogen are discussed. |
|
| Nucleation and Growth Mechanism of Diamond During Hot-Filament Chemical Vapour Deposition. |
1994 |
|
| Authors:
J. Singh; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| High-resolution transmission electron microscopy (hrtem) was employed to study the nucleation and subsequent growth mechanism of crystalline diamond growth on copper tem grids by the hot-filament chemical vapour deposition process. the hrtem revealed direct evidence for the formation of a diamond-like amorphous carbon layer 8-14 nm thick, in which small diamond microcrystallites about 2-5 nm across were embedded. these diamond microcrystallites were formed as a result of direct transformation of ... |
|
| Conference on Binary Optics. An Opportunity for Technical Exchange |
25 FEB 1993 |
427 pages |
| Authors:
Helen J. Cole; William C. Pittman; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The papers herein were presented at the Conference on Binary Optics held in Huntsville, AL, February 23-25, 1993. The papers were presented according to subject as follows: Modeling and Design, Fabrication, and Applications. Invited papers and tutorial viewgraphs presented on these subjects are included. |
|
| A Study of the Damage Tolerance Enhancement of Carbon/Epoxy Laminates by Utilizing an Outer Lamina of Ultra High Molecular Weight Polyethylene, |
OCT 1991 |
|
| Authors:
Alan T. Nettles; David G. Lance; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The damage tolerance of carbon/epoxy was examined when an outer layer of ultra high molecular weight polyethylene (Spectra) material was laminated with the specimen. Four types of (pi over 4) 16 ply quasi-isotropic panels were tested. The first contained no Spectra, while the others had one lamina of Spectra placed on either the top (impacted side), bottom or both surfaces of the composite plate. A range of impact energies up ... |
|
| Compression-After-Impact Testing of Thin Composite Materials, |
OCT 1991 |
|
| Authors:
Alan T. Nettles; Andrew J. Hodge; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A new method was devised to test composite specimens as thin as 8 plies and up to 7.6 cm in width for compression strength. This method utilizes a fixture incorporating the best features of the Celanese and IITRI fixtures combined with an anti-buckling jig. This new method uses up to 83% less material than the most commonly used compression-after-impact technique, and can also be performed on smaller loading frames since ... |
|
| Verification of Tooling for Robotic Welding |
AUG 91 |
|
| Authors:
Mark R. Osterloh; Karen E. Silwinski; Ronald R. Anderson; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A method for the verification of tooling for robotic welding involves a combination of computer simulations and visual inspections. The verification process ensures the accuracy of a mathematical model that represents the tooling in an off-line programming system that numerically simulates the operation of the robotic welding system. In so doing, the process helps to prevent damaging collisions between the welding equipment and the workpiece, to ensure that the tooling ... |
|
| Computerized Profilometer for Inspection of Welds |
AUG 91 |
|
| Authors:
M. A. Badinger; F. N. Stone; G. J. Drouant; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A third-generation profilometer for the inspection of butt welds includes a hand-held probe unit that operates in conjunction with a computer. In comparison with first- and second-generation profilometers, this one increases precision by reducing subjective inputs and the concomitant variations in outputs among different operators. In addition, the training of operators is simplified. (Author). |
|
| Evaluation of the Total Quality Management Implementation Strategy for the Advanced Solid Rocket Motor Project at NASA's Marshall Space Flight Center. |
MAY 1991 |
|
| Authors:
H. F. Schramm; K. W. Sullivan; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| An evaluation of the NASA's Marshall Space Flight Center (MSFC) strategy to implement Total Quality Management (TQM) in the Advanced Solid Rocket Motor (ASRM) Project is presented. The evaluation of the implementation strategy reflected the Civil Service personnel perspective at the project level. The external and internal environments at MSFC were analyzed for their effects on the ASRM TQM strategy. Organizational forms, cultures, management systems, problem solving techniques, and training ... |
|
| Identifying Bearing Balls with Radioisotopes |
APR 91 |
|
| Authors:
Myles F. Butner; John J. Collins; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A proposed scheme for identification of members of a manufactured lot of bearing balls is based on the detection of characteristic isotopes. The scheme was conceived to track precise bearing balls through various stages of assembly, disassembly, and processing. Such balls must not be stamped or otherwise marked for visual identification because their fine surface textures, diameters, and sphericities must be retained. (NTIS). |
|
| A Novel Method of Testing the Shear Strength of Thick Honeycomb Composites, |
MAR 1991 |
|
| Authors:
A. J. Hodge; A. T. Nettles; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Sandwich composites of aluminum and glass/phenolic honeycomb core were tested for shear strength before and after impact damage. The assessment of shear strength was performed in two ways; by four-point bend testing of sandwich beams and by a novel double lap shear (DLS) test. This novel testing technique was developed so smaller specimens could be used thus making the use of common laboratory scale fabrication and testing possible. The two ... |
|
| Robotics in Space-Age Manufacturing. |
MAR 1991 |
|
| Authors:
C. Jones; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Robotics technologies are developed to improve manufacturing |
|
| LDEF Mission Update: Composites in Space |
91 |
|
| Authors:
Anon; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The composite samples on board of nasa's long-duration exposure facility (ldef) had to cope with atomic-oxygen attack, micrometeoroid impacts, and other hazards. designed to help scientists and engineers understand changes in the properties and structure of materials after exposure to the space environment, ldef compares changes with predictions based on laboratory experiments. roughly 10,000 material and system test specimens filled ldef's 86 experiment trays. specimens were selected to measure either ... |
|
| Coatings Could Protect Composites from Hostile Space Environment. |
1991 |
|
| Authors:
Ann F. Whitaker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This paper concerned mmc in some important way and contained information about, utilized, or discussed these subjects: basic topics:, composite materials, pmc materials and material types:, coatings, epoxy matrix, ptfe coatings, parameter values relevant to the data:, hostile environments miscellaneous and special technical terms:, aerospace applications, space applications. |
|
| Coatings Could Protect Composites from Hostile Space Environment. |
1991 |
|
| Authors:
Ann F. Whitaker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This paper concerned mmc in some important way and contained information about, utilized, or discussed these subjects: basic topics:, composite materials, cr pmc, pmc materials and material types:, (c)f/epoxy, (c)f/polysulfone, c fibers, c/epoxy, c/polysulfone, coatings, epoxy matrix, fibers, polysulfone matrix material characteristics and data fields:, impact damages parameter values relevant to the data:, hostile environments, space environments, vacuum conditions testing and test conditions:, damage analysis, sem. |
|
| A Study of the Damage Tolerance Enhancement of Carbon/Epoxy Laminates by Utilizing an Outer Lamina of Ultra High Molecular Weight Polyethylene. |
1991 |
|
| Authors:
Alan T. Nettles; David G. Lance; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Low Velocity foreign object impact damage to carbon-fiber composites continue to be one of the most pressing problems involving the use of this type of material in many structures. In this paper, the damage tolerance of carbon/epoxy was examined when an outer layer of Ultra High Molecular Weight Polyethylene (Spcetra) material was utilized on the specimen. Four types of 16 ply quasi-isotropic panels, (0, +45, 90, -45)s2 were tested. The ... |
|
| Compression-After-Impact Testing of Thin Composite Materials. |
1991 |
|
| Authors:
Alan T. Nettles; Andrew J. Hodge; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A new method has been devised to test composite specimens as thin as 8 plies and up to 7.6cm (3.0in) in width for compression strength. This method utilizes a fixture incorporating the best features of the Celanese and IITRI fixtures combined with an anti-buckling jig developed at the University of Dayton Research Institute. This new method uses up to 83% less material than the most commonly used compression-after-impact technique (which ... |
|
| A Damage Tolerance Comparison of 7075-T6 Aluminum Alloy and IM7/977-2 Carbon/Epoxy. |
1991 |
|
| Authors:
Alan T. Nettles; David G. Lance; Andrew J. Hodge; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Low velocity impact damage of two materials, an aluminum alloy and a toughened resin reinforced with carbon fibers, were compared. Four levels of impact energy were used; 2.6 J, 5.3 J, 7.8 J and 9.9 J. The beams were compared for static strength and fatigue life by use of the four point bend flexure test. It was concluded that the IM7/977-2 demonstrated superior strength-to-weight performance than the 7075-T6 aluminum alloy ... |
|
| thermal-transient testing of turbine blades |
DEC 90 |
|
| Authors:
william r. wagner; louis h. pidcoke; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| a testing apparatus applies pulses of heat to a turbine blade to determine its resistance to thermal fatigue. the unit uses nonintrusive inductive heating and records the distribution of temperature on the blade with an infrared video camera. it allows precise control of heating and cooling. the unit is designed for testing blades used in advanced high-pressure, high- temperature turbines. such blades are damaged by thermal fatigue from thermal transients ... |
|
| averaging sampled sensor outputs to detect failures |
DEC 90 |
|
| Authors:
Hagop V. Panossian; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| a sampling-and-averaging technique processes noisy or otherwise erratic signals from a number of sensors to obtain indications of failures in a complicated system that contains the sensors. though the technique was devised to detect faults in the space shuttle main engine, the underlying concept could prove useful in monitoring automotive engines, chemical-processing plants, powerplants, and other systems in which the outputs of sensors contain noise or other fluctuations in the ... |
|
| inspecting the full circumferences of tubes |
NOV 90 |
|
| Authors:
john p. geddes; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| a proposed tool for the inspection of external welds on a tube would give a view of a full circumferential strip of the outer surface. the tool would be similar to the borescopes used to inspect the interiors of tubes. instead of fitting inside a tube, however, the new tool would encircle it. when a conventional borescope is used to inspect the outer surface of a tube, it must be ... |
|
| Eddy Current Inspection of Graphite Fiber Components |
OCT 90 |
|
| Authors:
G. L. Workman; C. C. Bryson; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The recognition of defects in materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques. The unique capabilities of E-probes and horseshoe probes for inspecting probes ... |
|
| Eddy Current Inspection of Graphite Fiber Components. |
OCT 1990 |
|
| Authors:
G. L. Workman; C. C. Bryson; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The recognition of defects in materials properties still presents a number of problems for nondestructive testing in aerospace systems. This project attempts to utilize current capabilities in eddy current instrumentation, artificial intelligence, and robotics in order to provide insight into defining geometrical aspects of flaws in composite materials which are capable of being evaluated using eddy current inspection techniques. The unique capabilities of E-probes and horsehoe probes for inspecting probes ... |
|
| An Examination of Impact Damage in Glass/Phenolic and Aluminum Honeycomb Core Composite Panels, |
AUG 1990 |
|
| Authors:
A. T. Nettles; D. G. Lance; A. J. Hodge; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Low velocity impact damage to glass/phenolic and aluminum core honeycomb sandwich panels with carbon/epoxy facesheets was examined. An instrumented drop weight impact test apparatus was utilized to inflict damage at energy ranges between 0.7 and 4.2 Joules. Specimens were checked for extent of damage by cross-sectional examination. The effect of core damage was assessed by subjecting impact-damaged beams to four-point bend tests. Skin-only specimens (facings not bonded to honeycomb) were ... |
|
| Low Velocity Instrumented Impact Testing of Four New Damage Tolerant Carbon/Epoxy Composite Systems |
JUL 90 |
40 pages |
| Authors:
D. G. Lance; A. T. Nettles; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Low velocity drop weight instrumented impact testing was utilized to examine the damage resistance of four recently developed carbon fiber/epoxy resin systems. A fifth material, T300/934, for which a large data base exists, was also tested for comparison purposes. A 16-ply quasi-isotropic lay-up configuration was used for all the specimens. Force/absorbed energy-time plots were generated for each impact test. The specimens were cross-sectionally analyzed to record the damage corresponding to ... |
|
| Low Velocity Intrumented Impact Testing of Four New Damage Tolerant Carbon/Epoxy Composite Systems, |
JUL 1990 |
|
| Authors:
D. G. Lance; A. T. Nettles; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Low velocity drop weight instrumented impact testing was utilized to examine the damage resistance of four recently developed carbon fiber/epoxy resin systems. A fifth material, T300/934, for which a large data base exists, was also tested for comparison purposes. A 16-ply quasi-isotropic lay-up configuration was used for all the specimens. Force/absorbed energy-time plots were generated for each impact test. The specimens were cross-sectionally analyzed to record the damage corrresponding to ... |
|
| Loads Analysis and Testing of Flight Configuration Solid Rocket Motor Outer Boot Ring Segments, |
JUN 1990 |
|
| Authors:
Rafiq Ahmed; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This report details the loads on in-house-fabricated flight configuration SRM outer boot ring segments. Test specimens consisted of carbon phenolic plies bonded to a backing of carbon phenolic plies having a differing orientation. The tests determined the bending strength and bending stiffness of these beams and showed that they compared well with the hand analysis. The bending stiffness test results compared very well with the finite element data. (Author, modified). ... |
|
| Instrumented Impact and Residual Tensile Strength Testing of Eight-Ply Carbon/Epoxy Specimens, |
JAN 1990 |
|
| Authors:
A. T. Nettles; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Instrumented drop weight impact testing was utilized to examine a puncture-type impact on thin carbon/epoxy coupons. Four different material systems with various eight-ply lay-up configurations were tested. Specimens were placed over a 10.3-mm diameter hole and impacted. Force-time plots as well as data on absorbed energy and residual tensile strength were gathered and examined. It was found that a critical impact energy level existed for each material tested, at which ... |
|
| Production of Continuous Mullite Fiber via Sol-Gel Processing |
90 |
|
| Authors:
Dennis S. Tucker; J. Scott Sparks; David C. Esker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
|
| Dynamic Fatigue of a Lithia-Alumina-Silica Glass-Ceramic |
90 |
|
| Authors:
Dennis S. Tucker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| A dynamic fatigue study was performed on Li2O-Al2O3-SiO2 glass- ceramic in order to assess its susceptibility to delayed failure. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions for optical elements made from this material. The material has reasonably good resistance (N=20) to stress corrosion in ambient conditions. Analysis also indicated the elements should survive applied stresses incurred during grinding and polishing operations. ... |
|
| Second Conference on NDE for Aerospace Requirements |
90 |
|
| Authors:
Kenneth W. Woodis; Craig C. Bryson; Gary L. Workman; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Nondestructive evaluation and inspection procedures must constantly improve rapidly in order to keep pace with corresponding advances being made in aerospace materials and systems. In response to this need, the 1989 Conference on NDE for Aerospace Requirements was organized to provide a forum for discussion between the materials scientists, systems designers, and NDE engineers who produce current and future aerospace systems. It is anticipated that problems in current systems can ... |
|
| Development and Applications of Nondestructive Evaluation at Marshall Space Flight Center |
90 |
|
| Authors:
Kenneth W. Woodis; Craig C. Bryson; Gary L. Workman; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| Paper describes the activities of various NDE facilities at the Marshall Space Flight Center. (NTIAC/gta). |
|
| The Effects of Temperature Gradient and Growth Rate on the Morphology and Fatigue Properties of MAR-M246(Hf) |
AUG 89 |
|
| Authors:
D. D. Schmidt; W. S. Alter; W. D. Hamilton; R. A. Parr; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| MAR-M246(Hf) is a nickel-based superalloy used in the turbopump blades of the Space Shuttle main engines. This study considers the effect of temperature gradient (G) and growth rate (R) on the microstructure and fatigue properties of this superalloy. The primary dendrite arm spacings were found to be inversely proportional to both temperature gradient and growth rate. Carbide and gamma-gamma prime morphology trends were related to G/R ratios. Weibull analysis of ... |
|
| Stress Corrosion Study of PH13-8Mo Stainless Steel Using the Slow Strain Rate Technique |
JUL 89 |
|
| Authors:
P. D. Torres; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| The need for a fast and reliable method to study stress corrosion in metals has caused increased interest in the Slow Strain Rate Technique (SSRT) during the last few decades. In this work, PH13-8Mo H950 and H1000 round tensile specimens were studied by this method. Percent reduction-in-area, time-to- failure, elongation at fracture, and fracture energy were used to express the loss in ductility, which has been used to indicate susceptibility ... |
|
| An Automated Protein Crystal Growth Facility on the Space Station. |
JUL 1989 |
|
| Authors:
M. C. Herrmann; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This paper addresses the need for an automated Protein Crystal Growth experiment on the Space Station and how robotics will be integrated into the system design. This automated laboratory system will enable several hundred protein crystals to grow simultaneously in microgravity and will allow the major variables in protein crystal growth to be monitored and controlled ruing the experiment. Growing good quality crystals is important in determining the complete structure ... |
|
| Orbital Maneuvering Vehicle (OMV) Remote Servicing Kit. |
JUL 1989 |
|
| Authors:
N. S. Brown; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| With the design and development of the Orbital Maneuvering Vehicle (OMV) progressing toward an early 1990's initial operating capability, a new era in remote space operations will evolve. The logical progression to OMV front end kits would make available in-situ satellite servicing, repair, and consummables resupply to the satellite community. Several conceptual design study efforts are defining representative kits (propellant tankers, debris recovery, module servicers); additional focus must also be ... |
|
| Development of Automation and Robotics for Space via Computer Graphic SImulation Methods. |
JUL 1989 |
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| Authors:
K. Fernandez; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
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| The development of advanced automation & robotics (A & R) for space and earth based systems requires that critical hardware and software issues be resolved. Robotic mechanisms must be controllable and have kinematics designs, dynamic characteristics, end-effectors and working environments correctly designed for their tasks. Software systems must be capable of controlling these mechanisms in a timely manner and adapting to operational changes, while telerobotic systems must also have user ... |
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| Results of Protective Coating Studies for the Hubble Space Telescope Solar Array, |
MAY 1989 |
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| Authors:
R. C. Linton; R. L. Gause; R. J. Harwell; R. F. DeHaye; H. D. Burns Jr.; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
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| Concerns for the erosive effects of orbital atomic oxygen on susceptible materials of the original high efficiency cell (HEC) solar array for the Hubble Space Telescope led to the development of a second-generation array (BSFR-ATOX) composed of oxygen resistant (protected) materials. A multi-disciplinary effort to develop and qualify feasible approaches for the application of protective coatings to the existing fabricated and flight-qualified HEC array was initiated in early 1987 as ... |
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| The Corrosion Protection of Aluminum by Various Anodizing Treatments |
APR 89 |
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| Authors:
M. D. Danford; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
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| Corrosion protection to 6061-T6 aluminum, afforded by both teflon- impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5% NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved ... |
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| Oblique Hypervelocity Impact Response of Dual-Sheet Structures |
JAN 89 |
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| Authors:
W. P. Schonberg; R. A. Taylor; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
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| This report describes the results of a continuing investigation of the phenomena associated with the oblique hypervelocity impact of spherical projectiles onto multi-sheet aluminum structures. A series of equations that quantitatively describes these phenomena is obtained through a regression of experimental data. These equations characterize observed ricochet and penetration damage phenomena in a multi-sheet structure as functions of geometric parameters of the structure and the diameter, obliquity, and velocity of ... |
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