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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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At least 235 records · Page 13

Shelf Life of PMR Polyimide Monomer Solutions and Prepregs Extended

PMR (Polymerization of Monomeric Reactants) technology was developed in the mid-1970's at the NASA Glenn Research Center at Lewis Field for fabricating high-temperature stable polyimide composites. This technology allowed a solution of polyimide monomers or prepreg (a fiber, such as glass or graphite, impregnated with PMR polyimide monomers) to be thermally cured without the release of volatiles that cause the formation of voids unlike the non-PMR technology used for polyimide condensation type resins. The initial PMR resin introduced as PMR 15 is still commercially available and is used worldwide by aerospace industries as the state-of-the-art resin for high-temperature polyimide composite applications. PMR 15 offers easy composite processing, excellent composite mechanical property retention, a long lifetime at use temperatures of 500 to 550 F, and relatively low cost. Later, second-generation PMR resin versions, such as PMR II 50 and VCAP 75, offer improvements in the upper-use temperature (to 700 F) and in the useful life at temperature without major compromises in processing and property retention but with significant increases in resin cost. Newer versions of nontoxic (non-methylene dianiline) PMR resins, such as BAX PMR 15, offer similar advantages as originally found for PMR 15 but also with significant increases in resin cost. Thus, the current scope of the entire PMR technology available meets a wide range of aeronautical requirements for polymer composite applications.

Alston, William B.↗

Coupled Solid Rocket Motor Ballistics and Trajectory Modeling for Higher Fidelity Launch Vehicle Design

Multi-stage launch vehicles with solid rocket motors (SRMs) face design optimization challenges, especially when the mission scope changes frequently. Significant performance benefits can be realized if the solid rocket motors are optimized to the changing requirements. While SRMs represent a fixed performance at launch, rapid design iterations enable flexibility at design time, yielding significant performance gains. The streamlining and integration of SRM design and analysis can be achieved with improved analysis tools. While powerful and versatile, the Solid Performance Program (SPP) is not conducive to rapid design iteration. Performing a design iteration with SPP and a trajectory solver is a labor intensive process. To enable a better workflow, SPP, the Program to Optimize Simulated Trajectories (POST), and the interfaces between them have been improved and automated, and a graphical user interface (GUI) has been developed. The GUI enables real-time visual feedback of grain and nozzle design inputs, enforces parameter dependencies, removes redundancies, and simplifies manipulation of SPP and POST's numerous options. Automating the analysis also simplifies batch analyses and trade studies. Finally, the GUI provides post-processing, visualization, and comparison of results. Wrapping legacy high-fidelity analysis codes with modern software provides the improved interface necessary to enable rapid coupled SRM ballistics and vehicle trajectory analysis. Low cost trade studies demonstrate the sensitivities of flight performance metrics to propulsion characteristics. Incorporating high fidelity analysis from SPP into vehicle design reduces performance margins and improves reliability. By flying an SRM designed with the same assumptions as the rest of the vehicle, accurate comparisons can be made between competing architectures. In summary, this flexible workflow is a critical component to designing a versatile launch vehicle model that can accommodate a volatile mission scope.

Ables, Brett↗

Human factors certification in the development of future air traffic control systems

If human factors certification of aviation technologies aims to encompass the wide range of issues which need to be addressed for any new system, then human factors involvement must be present throughout the whole design process in a manner which relates to final certification. A certification process cannot simply be applied to the final product of design. Standards and guidelines will be required by designers at the outset of design for reference in preparing for certification. The most effective use of human factors principles, methods, and measures is made as part of an iterative design process, leading to a system which reflects these as far as possible. This particularly applies where the technology is complex and may be represented by a number of components or sub-systems. Some aspects of the system are best certified during early prototyping, when there is still scope to make changes to software or hardware. At this stage in design, financial and/or time pressures will not rule out the possibility of necessary changes, as may be the case later. Other aspects of the system will be best certified during the final phases of design when the system is in a more complete form and in a realistic environment.

Evans, Alyson E.↗

Core and Off-Core Processes in Systems Engineering

An emerging methodology of organizing systems-engineering plans is based on a concept of core and off-core processes or activities. This concept has emerged as a result of recognition of a risk in the traditional representation of systems-engineering plans by a Vee model alone, according to which a large system is decomposed into levels of smaller subsystems, then integrated through levels of increasing scope until the full system is constructed. Actual systems-engineering activity is more complicated, raising the possibility that the staff will become confused in the absence of plans which explain the nature and ordering of work beyond the traditional Vee model.

Breidenthal, Julian↗

CCSDS - Advancing Spaceflight Technology for International Collaboration

The Consultative Committee for Space Data Systems (CCSDS) has been developing data and communications standards since 1982, with the objective of providing interoperability for enabling international collaboration for spaceflight missions. As data and communications technology has advanced, CCSDS has progressed to capitalize on existing products when available and suitable for spaceflight, and to develop innovative new approaches when available products fail. The current scope of the CCSDS architecture spans the end-to-end data architecture of a spaceflight mission, with ongoing efforts to develop and standardize cutting-edge technology. This manuscript describes the overall architecture, the position of CCSDS in the standards and international mission community, and some CCSDS processes. It then highlights in detail several of the most interesting and critical technical areas in work right now, and how they support collaborative missions. Special topics include: Delay/Disruption Tolerant Networking (DTN), Asynchronous Message Service (AMS), Multispectral/Hyperspectral Data Compression (MHDC), Coding and Synchronization, Onboard Wireless, Spacecraft Monitor and Control, Navigation, Security, and Time Synchronization/Correlation. Broad international participation in development of CCSDS standards is encouraged.

Kearney, Mike↗

A New Direction for the NASA Materials Science Research Using the International Space Station

In 2001 NASA created a fifth Strategic Enterprise, the Office of Biological and Physical Research (OBPR), to bring together physics, chemistry, biology, and engineering to foster interdisciplinary research. The Materials Science Program is one of five Microgravity Research disciplines within this new Enterprise's Division of Physical Sciences Research. The Materials Science Program will participate within this new enterprise structure in order to facilitate effective use of ISS facilities, target scientific and technology questions and transfer results for Earth benefits. The Materials Science research will use a low gravity environment for flight and ground-based research in crystallization, fundamental processing, properties characterization, and biomaterials in order to obtain fundamental understanding of various phenomena effects and relationships to the structures, processing, and properties of materials. Completion of the International Space Station's (ISS) first major assembly, during the past year, provides new opportunities for on-orbit research and scientific utilization. The Enterprise has recently completed an assessment of the science prioritization from which the future materials science ISS type payloads will be implemented. Science accommodations will support a variety of Materials Science payload hardware both in the US and international partner modules with emphasis on early use of Express Rack and Glovebox facilities. This paper addresses the current scope of the flight and ground investigator program. These investigators will use the various capabilities of the ISS lab facilities to achieve their research objectives. The type of research and classification of materials being studied will be addressed. This includes the recent emphasis being placed on radiation shielding, nanomaterials, propulsion materials, and biomaterials type research. The Materials Science Program will pursue a new, interdisciplinary approach, which contributes, to Human Space Flight Exploration research. The Materials Science Research Facility (MSRF) and other related American and International experiment modules will serve as the foundation for the flight research environment. A summary will explain the concept for materials science research processing capabilities aboard the ISS along with the various ground facilities necessary to support the program.

Schlagheck, Ronald A.↗

The Challenges of Releasing Human Data for Analysis

The NASA Johnson Space Center s (NASA JSC) Committee for the Protection of Human Subjects (CPHS) recently approved the formation of two human data repositories: the Lifetime Surveillance of Astronaut Health Repository (LSAH-R) for clinical data and the Life Sciences Data Archive Repository (LSDA-R) for research data. The establishment of these repositories forms the foundation for the release of data and information beyond the scope for which the data was originally collected. The release of clinical and research data and information is primarily managed by two NASA groups: the Evidence Base Working Group (EBWG), consisting of members of both repositories, and the LSAH Policy Board. The goal of unifying these repositories and their processes is to provide a mutually supportive approach to handling medical and research data, to enhance the use of medical and research data to reduce risk, and to promote the understanding of space physiology, countermeasures and other mitigation strategies. Over the past year, both repositories have received over 100 data and information requests from a wide variety of requesters. The disposition of these requests has highlighted the challenges faced when attempting to make data collected on a unique set of subjects available beyond the original intent for which the data were collected. As the EBWG works through each request, many considerations must be factored into account when deciding what data can be shared and how - from the Privacy Act of 1974 and the Health Insurance Portability and Accountability Act (HIPAA), to NASA s Health Information Management System (10HIMS) and Human Experimental and Research Data Records (10HERD) access requirements. Additional considerations include the presence of the data in the repositories and vetting requesters for legitimacy of their use of the data. Additionally, fair access must be ensured for intramural, as well as extramural investigators. All of this must be considered in the formulation of the charters, policies and workflows for the human data repositories at NASA.

Fitts, Mary↗

Toward full life cycle control: Adding maintenance measurement to the SEL

Organization-wide measurement of software products and processes is needed to establish full life cycle control over software products. The Software Engineering Laboratory (SEL)--a joint venture between NASA GSFC, the University of Maryland, and Computer Sciences Corporation--started measurement of software development more than 15 years ago. Recently, the measurement of maintenance was added to the scope of the SEL. In this article, the maintenance measurement program is presented as an addition to the already existing and well-established SEL development measurement program and evaluated in terms of its immediate benefits and long-term improvement potential. Immediate benefits of this program for the SEL include an increased understanding of the maintenance domain, the differences and commonalities between development and maintenance, and the cause-effect relationships between development and maintenance. Initial results from a sample maintenance study are presented to substantiate these benefits. The long-term potential of this program includes the use of maintenance baselines to better plan and manage future projects and to improve development and maintenance practices for future projects wherever warranted.

Rombach, H. Dieter↗

Advanced Biotelemetry Systems for Space Life Sciences: PH Telemetry

The SENSORS 2000! (S2K!) program at NASA's Ames Research Center is currently developing a biotelemetry system for monitoring pH and temperature in unrestrained subjects. This activity is part of a broader scope effort to provide an Advanced Biotelemetry System (ABTS) for use in future space life sciences research. Many anticipated research endeavors will require biomedical and biochemical sensors and related instrumentation to make continuous inflight measurements in a variable-gravity environment. Since crew time is limited, automated data acquisition, data processing, data storage, and subject health monitoring are required. An automated biochemical and physiological data acquisition system based on non invasive or implantable biotelemetry technology will meet these requirements. The ABTS will ultimately acquire a variety of physiological measurands including temperature, biopotentials (e.g. ECG, EEG, EMG, EOG), blood pressure, flow and dimensions, as well as chemical and biological parameters including pH. Development activities are planned in evolutionary, leveraged steps. Near-term activities include 1) development of a dual channel pH/temperature telemetry system, and 2) development of a low bandwidth, 4-channel telemetry system, that measures temperature, heart rate, pressure, and pH. This abstract describes the pH/temperature telemeter.

Hines, John W.↗

Coal gasification systems engineering and analysis. Appendix A: Coal gasification catalog

The scope of work in preparing the Coal Gasification Data Catalog included the following subtasks: (1) candidate system subsystem definition, (2) raw materials analysis, (3) market analysis for by-products, (4) alternate products analysis, (5) preliminary integrated facility requirements. Definition of candidate systems/subsystems includes the identity of and alternates for each process unit, raw material requirements, and the cost and design drivers for each process design.

Source record↗

Design of a compliant wheel for a miniature rover to be used on Mars

The Jet Propulsion Laboratory has identified the need for a compliant wheel for a miniature martian rover vehicle. This wheel must meet requirements of minimum mass, linear radial deflection, and reliability in cryogenic conditions over a five year lifespan. Additionally, axial and tangential deflections must be no more than 10 percent of the radial value. The team designed a wheel by use of finite element and dimensionless parameter analysis. Due to the complex geometry of the wheel, a finite element model describing its behavior was constructed to investigate different wheel configurations. Axial and tangential deflections were greatly reduced but did not meet design criteria. A composite material was selected for its high strength, toughness, fatigue resistance, and damping characteristics. The team chose a Kevlar fiber filled thermoplastic composite. This report is divided into four primary sections. First, the introduction section gives background information, defines the task, and discusses the scope and limitations of the project. Second, the alternative designs section introduces alternative design solutions, addresses advantages and disadvantages of each, and identifies the parameters used to determine the best design. Third, the design solution section introduces the methods used to evaluate the alternates, and gives a description of the design process used. Finally, the conclusion and recommendations section evaluates the wheel design, and offers recommendations pertaining to improvement of the design solution.

Carroll, Mark↗

The Buffer Diagnostic Prototype: A fault isolation application using CLIPS

This paper describes problem domain characteristics and development experiences from using CLIPS 6.0 in a proof-of-concept troubleshooting application called the Buffer Diagnostic Prototype. The problem domain is a large digital communications subsystems called the real-time network (RTN), which was designed to upgrade the launch processing system used for shuttle support at KSC. The RTN enables up to 255 computers to share 50,000 data points with millisecond response times. The RTN's extensive built-in test capability but lack of any automatic fault isolation capability presents a unique opportunity for a diagnostic expert system application. The Buffer Diagnostic Prototype addresses RTN diagnosis with a multiple strategy approach. A novel technique called 'faulty causality' employs inexact qualitative models to process test results. Experimental knowledge provides a capability to recognize symptom-fault associations. The implementation utilizes rule-based and procedural programming techniques, including a goal-directed control structure and simple text-based generic user interface that may be reusable for other rapid prototyping applications. Although limited in scope, this project demonstrates a diagnostic approach that may be adapted to troubleshoot a broad range of equipment.

Porter, Ken↗

Space environment and lunar surface processes

The development of a general rock/soil model capable of simulating in a self consistent manner the mechanical and exposure history of an assemblage of solid and loose material from submicron to planetary size scales, applicable to lunar and other space exposed planetary surfaces is discussed. The model was incorporated into a computer code called MESS.2 (model for the evolution of space exposed surfaces). MESS.2, which represents a considerable increase in sophistication and scope over previous soil and rock surface models, is described. The capabilities of previous models for near surface soil and rock surfaces are compared with the rock/soil model, MESS.2.

Comstock, G. M.↗

Project LAUNCH: Bringing Space into Math and Science Classrooms

Project LAUNCH is a K-12 teacher professional development program, which has been created in collaboration between the Whitaker Center for Science, Mathematics and Technology Education at Florida Gulf Coast University (FGCU), and the Florida Space Research Institute (FSRI). Utilizing Space as the overarching theme it is designed to improve mathematics and science teaching, using inquiry based, hands-on teaching practices, which are aligned with Florida s Sunshine State Standards. Many students are excited about space exploration and it provides a great venue to get them involved in science and mathematics. The scope of Project LAUNCH however goes beyond just providing competency in the subject area, as pedagogy is also an intricate part of the project. Participants were introduced to the Conceptual Change Model (CCM) [1] as a framework to model good teaching practices. As the CCM closely follows what scientists call the scientific process, this teaching method is also useful to actively engage institute participants ,as well as their students, in real science. Project LAUNCH specifically targets teachers in low performing, high socioeconomic schools, where the need for skilled teachers is most critical.

Fauerbach, M.↗

Closed-ecology life support systems /CELSS/ for long-duration, manned missions

Studies were conducted to scope the principal areas of technology that can contribute to the development of closed-ecology life support systems (CELSS). Such systems may be required for future space activities, such as space stations, manufacturing facilities, or colonies. A major feature of CELSS is the regeneration of food from carbon in waste materials. Several processes, using biological and/or physico-chemical components, have been postulated for closing the recycle loop. At the present time, limits of available technical information preclude the specification of an optimum scheme. Nevertheless, the most significant technical requirements can be determined by way of an iterative procedure of formulating, evaluating and comparing various closed-system scenario. The functions features and applications of this systems engineering procedure are discussed.

Modell, M.↗

Airloads research study. Volume 1: Flight test loads acquisition

The acquisition of B-1 aircraft flight loads data for use in subsequent tasks of the Airloads Research Study is described. The basic intent is to utilize data acquired during B-1 aircraft tests, analyze these data beyond the scope of Air Force requirements, and prepare research reports that will add to the technology base for future large flexible aircraft. Flight test data obtained during the airloads survey program included condition-describing parameters, surface pressures, strain gage outputs, and loads derived from pressure and strain gauges. Descriptions of the instrumentation, data processing, and flight load survey program are included. Data from windup-turn and steady yaw maneuvers cover a Mach number range from 0.7 to 2.0 for a wing sweep position of 67.5 deg.

Bartlett, M. D.↗

Expert system-based mineral mapping using AVIRIS

Integrated analysis of imaging spectrometer data and field spectral measurements were used in conjunction with conventional geologic field mapping to characterize bedrock and surficial geology at the northern end of Death Valley, California and Nevada. A knowledge-based expert system was used to automatically produce image maps from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data showing the principal surface mineralogy. The imaging spectrometer data show the spatial distribution of spectrally distinct minerals occurring both as primary rock-forming minerals and as alteration and weathering products. Field spectral measurements were used to verify the mineral maps and field mapping was used to extend the remote sensing results. Geographically referenced image-maps produced from these data form new base maps from which to develop improved understanding of the processes of deposition and erosion affecting the present land surface. The 'northern Grapevine Mountains' (NGM) study area was reported on in numerous papers. This area is an unnamed northwestward extension of the range. Most of the research here has concentrated on mapping of Jurassic-age plutons and associated hydrothermal alteration, however, the nature and scope of these studies is much broader, pertaining to the geologic history and development of the entire Death Valley region. AVIRIS data for the NGM site were obtained during May 1989. Additional AVIRIS data were acquired during September 1989 as part of the Geologic Remote Sensing Field Experiment (GRSFE). The area covered by these data overlaps slightly with the May 1989 data. Three and one-half AVIRIS scenes total were analyzed.

Kruse, Fred A.↗

Design of Control Software for a High-Speed Coherent Doppler Lidar System for CO2 Measurement

The design of the software for a 2-micron coherent high-speed Doppler lidar system for CO2 measurement at NASA Langley Research Center is discussed in this paper. The specific strategy and design topology to meet the requirements of the system are reviewed. In order to attain the high-speed digitization of the different types of signals to be sampled on multiple channels, a carefully planned design of the control software is imperative. Samples of digitized data from each channel and their roles in data analysis post processing are also presented. Several challenges of extremely-fast, high volume data acquisition are discussed. The software must check the validity of each lidar return as well as other monitoring channel data in real-time. For such high-speed data acquisition systems, the software is a key component that enables the entire scope of CO2 measurement studies using commercially available system components.

Vanvalkenburg, Randal L.↗