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Description of two axial alignment fixtures that are capable of providing very low load application eccentricity in tension tests of threaded notched cylindrical specimens. The described fixtures are simple in design, very compact, and free from the effects of friction. Also, an evaluation procedure is presented that can be used to qualify any fixture for use in sharp notch tensile tests.
The new 9.6-kbps wideband data rate capability in the DSN is reviewed. A functional description of the completed implementation is presented, together with a plan to upgrade the central communications terminal for additional 9.6 s operational flexibility.
A general technical description of the extravehicular mobility unit (EMU) is given. The description provides a basis for understanding EMU mobility capabilities and the environments a payload is exposed to in the vicinity of an EMU.
The advantage of 32-GHz links, the estimated link performance, and developments in the fields of antennas, low noise preamplifiers, radiometry, and propagation studies are discussed. A description of ways to demonstrate 32-GHz link capability concludes the discussion.
The rationale for a manned mission to the satellites of Mars is discussed. The view has been expressed that NASA must define a major program to follow the Shuttle and to utilize it. However, such a program could not be initiated and proceed without public support, and to obtain this support, public interest would have to be excited. It is shown that, of a number of possible targets for manned exploration in the solar system, Mars appears to be the only possible candidate. Attention is given to a comparison of three Mars missions, a Mars 1984 mission, a manned landing on Mars surface, a manned landing on Phobos and Deimos (Ph-D project), putting men in Mars orbit, the capabilities of the Ph-D mission, a description of the spacecraft, a Ph-D project operations plan, and aspects of timing, technology, and costs.
The acousto-ultrasonic method of nondestructive evaluation is an extremely sensitive means of assessing material response. Efforts continue to complete the understanding of this method. In order to achieve the full sensitivity of the technique, extreme care must be taken in its performance. This report provides an update of the efforts to advance the understanding of this method and to increase its application to the nondestructive evaluation of composite materials. Included are descriptions of a novel optical system that is capable of measuring in-plane and out-of-plane displacements, an IBM PC-based data acquisition system, an extensive data analysis software package, the azimuthal variation of acousto-ultrasonic behavior in graphite/epoxy laminates, and preliminary examination of processing variation in graphite-aluminum tubes.
Four topics in landing gear dynamics are discussed. Three of these topics are subjects of recent research: tilt steering phenomenon, water spray ingestion on flooded runways, and actively controlled landing gear. The fourth topic is a description of a major facility recently enhanced in capability.
The definition of the Extravehicular Activity (EVA) systems interface requirements and accomodations for effective integration of a production EVA capability into the space station are contained. A description of the EVA systems for which the space station must provide the various interfaces and accomodations are provided. The discussion and analyses of the various space station areas in which the EVA interfaces are required and/or from which implications for EVA system design requirements are derived, are included. The rationale is provided for all EVAS mechanical, fluid, electrical, communications, and data system interfaces as well as exterior and interior requirements necessary to facilitate EVA operations. Results of the studies supporting these discussions are presented in the appendix.
This manual describes the user options available for running the MHOST finite element analysis package. MHOST is a solid and structural analysis program based on mixed finite element technology, and is specifically designed for three-dimensional inelastic analysis. A family of two- and three-dimensional continuum elements along with beam and shell structural elements can be utilized. Many options are available in the constitutive equation library, the solution algorithms and the analysis capabilities. An overview of the algorithms, a general description of the input data formats, and a discussion of input data for selecting solution algorithms are given.
TOPEX/Poseidon, a scientific satellite to be launched into low earth orbit, will map the surface topography of the earth's oceans. The satellite derives its primary electrical power from a deployable, sun tracking, rigid, single wing, rectangular solar array with overall dimensions of approximately 26 by 11 ft. The requirements which affect the electrical performance of the solar array and the method by which each requirement is satisfied are addressed. The worst-case power calculations used to size the solar array and to verify power capability are discussed. Also included is a detailed description of the solar array configuration and a summary of the qualification and acceptance testing.
The Aircraft Landing Dynamics Facility (ALDF) is a unique facility with the ability to test aircraft landing gear systems on actual runway surfaces at operational ground speeds and loading conditions. A brief historical overview of the original Landing Loads Track (LLT) is given, followed by a detailed description of the new ALDF systems and operational capabilities.
This document describes the simulation approach used to test the performance of the NASA airborne windshear radar. An explanation of the actual radar hardware and processing algorithms provides an understanding of the parameters used in the simulation program. This report also contains a brief overview of the NASA airborne windshear radar experimental flight test results. A description of the radar simulation program shows the capabilities of the program and the techniques used for certification evaluation. Simulation of the NASA radar is comprised of three steps. First, the choice of the ground clutter data must be made. The ground clutter is the return from objects in or nearby an airport facility. The choice of the ground clutter also dictates the aircraft flight path since ground clutter is gathered while in flight. The second step is the choice of the radar parameters and the running of the simulation program which properly combines the ground clutter data with simulated windshear weather data. The simulated windshear weather data is comprised of a number of Terminal Area Simulation System (TASS) model results. The final step is the comparison of the radar simulation results to the known windshear data base. The final evaluation of the radar simulation is based on the ability to detect hazardous windshear with the aircraft at a safe distance while at the same time not displaying false alerts.
With the successful implementation of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) enters a new era of opportunity for scientific research. The ISS provides a working laboratory in space, with tremendous capabilities for scientific research. Utilization of these capabilities requires a launch system capable of routinely transporting crew and logistics to/from the ISS, as well as supporting ISS assembly and maintenance tasks. The Space Shuttle serves as NASA's launch system for performing these functions. The Space Shuttle also serves as NASA's launch system for supporting other science and servicing missions that require a human presence in space. The Space Shuttle provides proof that reusable launch vehicles are technically and physically implementable. However, a couple of problems faced by NASA are the prohibitive cost of operating and maintaining the Space Shuttle and its relative inability to support high launch rates. The 2nd Generation Reusable Launch Vehicle (2nd Gen RLV) is NASA's solution to this problem. The 2nd Gen RLV will provide a robust launch system with increased safety, improved reliability and performance, and less cost. The improved performance and reduced costs of the 2nd Gen RLV will free up resources currently spent on launch services. These resource savings can then be applied to scientific research, which in turn can be supported by the higher launch rate capability of the 2nd Gen RLV. The result is a win - win situation for science and NASA. While meeting NASA's needs, the 2nd Gen RLV also provides the United States aerospace industry with a commercially viable launch capability. One of the keys to achieving the goals of the 2nd Gen RLV is to develop and implement new technologies and processes in the area of flight operations. NASA's experience in operating the Space Shuttle and the ISS has brought to light several areas where automation can be used to augment or eliminate functions performed by crew and ground controllers. This experience has also identified the need for new approaches to staffing and training for both crew and ground controllers. This paper provides a brief overview of the mission capabilities provided by the 2nd Gen RLV, a description of NASA's approach to developing the 2nd Gen RLV, a discussion of operations concepts, and a list of challenges to implementing those concepts.
Presented is a description of a computer program which permits assessment of the operational support requirements of space transportation systems functioning in both a ground- and space-based environment. The scenario depicted provides for the delivery of payloads from Earth to a space station and beyond using upper stages based at the station. Model results are scenario dependent and rely on the input definitions of delivery requirements, task times, and available resources. Output is in terms of flight rate capabilities, resource requirements, and facility utilization. A general program description, program listing, input requirements, and sample output are included.
Increasing the fuel burnup limit in light water reactors is sought to enhance fuel cycle economics and requires establishing a technical basis. Experimental observations of severe fuel fragmentation under loss-of-coolant-accident conditions at Halden and Studsvik had raised the need for additional considerations during the development of this technical basis. These test data suggested that the burnup threshold for high burnup fuel fragmentation may be influenced by pre-transient power. Additional loss-of-coolant-accident test data is therefore valuable to complement these tests and enhance the current state of understating. Oak Ridge National Lab has developed the Severe Accident Test Station capable of examining the oxidation kinetics and accident response of irradiated fuel and cladding materials for design basis accident and beyond design basis accident scenarios. Severe Accident Test Station provides various temperature profiles, steam, and the thermal shock conditions necessary for integral loss of coolant accident testing, defueled oxidation quench testing, and high-temperature beyond design basis accident testing. Severe Accident Test Station has been successfully installed and demonstrated in the Irradiated Fuels Examination Laboratory at Oak Ridge National Lab. Furthermore, descriptions of the in-cell re-fabrication capabilities and assembly of the loss-of-coolant-accident test train are provided. Installation of the Severe Accident Test Station system and in-cell re-fabrication restores United States capability to examine postulated and extended loss-of-coolant-accident conditions on spent fuel and cladding and provides a platform for evaluating advanced fuel and accident-tolerant fuel cladding concepts. Lastly, three in-cell integral loss-of-coolant-accident test were performed in the Severe Accident Test Station and compared to the Nuclear Regulatory Commission sponsored loss-of-coolant-accident test as well as the original loss-of-coolant-accident test performed at Argonne National Lab. Finally, the results of these tests as well as all publicly available integral loss-of-coolant-accident test were used to validate a threshold for high burnup fuel fragmentation.
Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. The SD module rejects waste heat from the power conversion cycle to space through a pumped-loop, multi-panel, deployable radiator. The baseline radiator configuration was defined during the Space Station conceptual design phase and is a function of the state point and heat rejection requirements of the power conversion unit. Requirements determined by the overall station design such as mass, system redundancy, micrometeoroid and space debris impact survivability, launch packaging, costs, and thermal and structural interaction with other station components have also been design drivers for the radiator configuration. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations. A brief description and discussion of the numerical model, it's capabilities and limitations, and results of the parametric studies performed is presented.
This document is the third volume in the three volume set of User's Manuals for the Micromechanics Analysis Code with Generalized Method of Cells Version 4.0 (MAC/GMC 4.0). Volume 1 is the Theory Manual, Volume 2 is the Keywords Manual, and this document is the Example Problems Manual. MAC/GMC 4.0 is a composite material and laminate analysis software program developed at the NASA Glenn Research Center. It is based on the generalized method of cells (GMC) micromechanics theory, which provides access to the local stress and strain fields in the composite material. This access grants GMC the ability to accommodate arbitrary local models for inelastic material behavior and various types of damage and failure analysis. MAC/GMC 4.0 has been built around GMC to provide the theory with a user-friendly framework, along with a library of local inelastic, damage, and failure models. Further, application of simulated thermo-mechanical loading, generation of output results, and selection of architectures to represent the composite material, have been automated in MAC/GMC 4.0. Finally, classical lamination theory has been implemented within MAC/GMC 4.0 wherein GMC is used to model the composite material response of each ply. Consequently, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. This volume provides in-depth descriptions of 43 example problems, which were specially designed to highlight many of the most important capabilities of the code. The actual input files associated with each example problem are distributed with the MAC/GMC 4.0 software; thus providing the user with a convenient starting point for their own specialized problems of interest.
The Arc-Heated Scramjet Test Facility at NASA Langley Research Center has demonstrated itself repeatedly as a key contributor to fundamental hypersonic research and scramjet engine technology development in the Mach 4.7 to 8 range. Since its inception in the 1970’s, the facility has hosted numerous scramjet engine configurations that explored the performance and operability of airframe-integrated hydrogen-fueled scramjet flow path concepts, successfully maturing both analysis tools and design technique and methodology for hypersonic propulsion. Contributions to major programs include extensive tests of the hydrogen-fueled NASP and Hyper-X scramjet engines, and the hydrocarbon-fueled HIFiRE Flight 2 scramjet flow path, in addition to fundamental in-house research. The facility capabilities have expanded to include direct-connect flow path support, gaseous hydrocarbon fuels, dynamic trajectory simulation and extension of flight simulation down to Mach 2.2. The low-Mach upgrades include increased air flow rate and controls capability and two new low-Mach nozzles (Mach 2.2 and 3.5). The facility recently completed verification of the new operational range through successful envelope expansion tests with the Mach 2.2 nozzle. With these new modifications, the operating envelope for the facility is now Mach 2.2 – 8.0(+), with a demonstrated dynamic pressure simulation of 2000 psf at the low end, and margin available for even more. Lastly, a continuous run time of over 5 minutes has been demonstrated, indicating that run time is limited only by test hardware or back-pressure requirements. This paper will provide a detailed description of these previously unreported upgrades and expanded simulation capabilities.