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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 181 records · Page 10

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NASA NTRS1992

LV software support for supersonic flow analysis

The software for configuring an LV counter processor system has been developed using structured design. The LV system includes up to three counter processors and a rotary encoder. The software for configuring and testing the LV system has been developed, tested, and included in an overall software package for data acquisition, analysis, and reduction. Error handling routines respond to both operator and instrument errors which often arise in the course of measuring complex, high-speed flows. The use of networking capabilities greatly facilitates the software development process by allowing software development and testing from a remote site. In addition, high-speed transfers allow graphics files or commands to provide viewing of the data from a remote site. Further advances in data analysis require corresponding advances in procedures for statistical and time series analysis of nonuniformly sampled data.

Bell, W. A.↗

NASA NTRS2005

Identifying Contingency Requirements using Obstacle Analysis on an Unpiloted Aerial Vehicle

This paper describes experience using Obstacle Analysis to identify contingency requirements on an unpiloted aerial vehicle. A contingency is an operational anomaly, and may or may not involve component failure. The challenges to this effort were: ( I ) rapid evolution of the system while operational, (2) incremental autonomy as capabilities were transferred from ground control to software control and (3) the eventual safety-criticality of such systems as they begin to fly over populated areas. The results reported here are preliminary but show that Obstacle Analysis helped (1) identify new contingencies that appeared as autonomy increased; (2) identify new alternatives for handling both previously known and new contingencies; and (3) investigate the continued validity of existing software requirements for contingency handling. Since many mobile, intelligent systems are built using a development process that poses the same challenges, the results appear to have applicability to other similar systems.

fault protection↗

NASA NTRS1986

Coal-Based Fuel-Cell Powerplants

Report assesses advanced technologyy design alternatives for integrated coal-gasifier/fuel-cell powerplants. Various gasifier, cleanup, and fuelcell options evaluated. Evaluation includes adjustments to assumed performances and costs of proposed technologies where required. Analysis identifies uncertainties remaining in designs and most promising alternatives and research and development required to develop these technologies. Bulk of report summary and detailed analysis of six major conceptual designs and variations of each. All designs for plant that uses Illinois No. 6 coal and produces 675 MW of net power.

Ferral, J. F.↗

NASA NTRS1976

Development and analysis of a modular approach to payload specialist training

A modular training approach for Spacelab payload crews is described. Representative missions are defined for training requirements analysis, training hardware, and simulations. Training times are projected for each experiment of each representative flight. A parametric analysis of the various flights defines resource requirements for a modular training facility at different flight frequencies. The modular approach is believed to be more flexible, time saving, and economical than previous single high fidelity trainer concepts. Block diagrams of training programs are shown.

Watters, H.↗

DOE OSTI2026

Cyber-Informed Engineering Requirements Framework Use Cases

The requirement analysis use case effort leverages the Cyber-Informed Engineering (CIE) requirements framework to examine two real-world scenarios: Battery Energy Storage System (BESS) installation at the Flatirons Campus, NLR; SCADA improvement program. This work evaluates the existing requirements for each use case, applies the CIE requirements framework, and assesses the benefits and enhancements gained compared to the current requirements. The results will advance CIE from concept to practical application by identifying key opportunities for integrating CIE principles into established engineering workflows during the requirements phase.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1978

Space station thermal control surfaces. Volume 1: Interim report

The U.S. space program goals for long-duration manned missions place particular demands on thermal-control systems. The objective of this program is to develop plans which are based on the present thermal-control technology, and which will keep pace with the other space program elements. The program tasks are as follows: (1) requirements analysis, with the objectives to define the thermal-control-surface requirements for both space station and 25 kW power module, to analyze the missions, and to determine the thermal-control-surface technology needed to satisfy both sets of requirements; (2) technology assessment, with the objectives to perform a literature/industry survey on thermal-control surfaces, to compare current technology with the requirements developed in the first task, and to determine what technology advancements are required for both the space station and the 25 kW power module; and (3) program planning that defines new initiative and/or program augmentation for development and testing areas required to provide the proper environment control for the space station and the 25 kW power module.

Maag, C. R.↗

NASA NTRS1996

Processing Satellite Images on Tertiary Storage: A Study of the Impact of Tile Size on Performance

Before raw data from a satellite can be used by an Earth scientist, it must first undergo a number of processing steps including basic processing, cleansing, and geo-registration. Processing actually expands the volume of data collected by a factor of 2 or 3 and the original data is never deleted. Thus processing and storage requirements can exceed 2 terrabytes/day. Once processed data is ready for analysis, a series of algorithms (typically developed by the Earth scientists) is applied to a large number of images in a data set. The focus of this paper is how best to handle such images stored on tape using the following assumptions: (1) all images of interest to a scientist are stored on a single tape, (2) images are accessed and processed in the order that they are stored on tape, and (3) the analysis requires access to only a portion of each image and not the entire image.

Yu, JieBing↗

NASA NTRS1998

Designing for Change: Minimizing the Impact of Changing Requirements in the Later Stages of a Spaceflight Software Project

In the traditional 'waterfall' model of the software project life cycle, the Requirements Phase ends and flows into the Design Phase, which ends and flows into the Development Phase. Unfortunately, the process rarely, if ever, works so smoothly in practice. Instead, software developers often receive new requirements, or modifications to the original requirements, well after the earlier project phases have been completed. In particular, projects with shorter than ideal schedules are highly susceptible to frequent requirements changes, as the software requirements analysis phase is often forced to begin before the overall system requirements and top-level design are complete. This results in later modifications to the software requirements, even though the software design and development phases may be complete. Requirements changes received in the later stages of a software project inevitably lead to modification of existing developed software. Presented here is a series of software design techniques that can greatly reduce the impact of last-minute requirements changes. These techniques were successfully used to add built-in flexibility to two complex software systems in which the requirements were expected to (and did) change frequently. These large, real-time systems were developed at NASA Langley Research Center (LaRC) to test and control the Lidar In-Space Technology Experiment (LITE) instrument which flew aboard the space shuttle Discovery as the primary payload on the STS-64 mission.

Allen, B. Danette↗

NASA NTRS1997

Reuse of a Formal Model for Requirements Validation

This paper report experience from how a project engaged in the process of requirements analysis for evolutionary builds can reuse the formally specified design model produced for a similar, earlier project in the same domain.

requirements↗

NASA NTRS1993

Integrating interface slicing into software engineering processes

Interface slicing is a tool which was developed to facilitate software engineering. As previously presented, it was described in terms of its techniques and mechanisms. The integration of interface slicing into specific software engineering activities is considered by discussing a number of potential applications of interface slicing. The applications discussed specifically address the problems, issues, or concerns raised in a previous project. Because a complete interface slicer is still under development, these applications must be phrased in future tenses. Nonetheless, the interface slicing techniques which were presented can be implemented using current compiler and static analysis technology. Whether implemented as a standalone tool or as a module in an integrated development or reverse engineering environment, they require analysis no more complex than that required for current system development environments. By contrast, conventional slicing is a methodology which, while showing much promise and intuitive appeal, has yet to be fully implemented in a production language environment despite 12 years of development.

Beck, Jon↗

NASA NTRSDate not supplied

Expedited Model Building Method for Rocket Nozzle Side Loading

Statistical analysis of test data is currently the preferred method of creating models for uncharacterized side loading in rocket nozzles. However, statistical analysis requires multiple data sets to be reliable; getting these sets requires building and testing multiple rocket motors, which is not feasible given the incredible time and cost required to do so. By using a combination of geometry, simplified finite element analysis (FEA) analogs, and algebra we can create a limited predictive model from only one test data set. Once created, the model requires only the input from one strain gauge located at each yaw and pitch attachment bracket for the actuation system. This process is not computationally intensive, therefore saving an abundance of time and budget over using full 3D FEA models to develop a similar predictive model. To develop the model, conversion factors between the strain at the gauge locations and corresponding actuator load is derived from the data. These conversion factors are used to create a “conversion ellipse” that bounds the constitutive properties of the nozzle as one lumped factor. Using a 2D cross-sectional analog of the nozzle exit plane, we create a function that allows us to determine the azimuthal location of the unexpected load based on the ratio between yaw and pitch strain readings. Combining this with the “conversion ellipse” yields a function that given the strain reading outputs an induced actuator load, regardless of the azimuthal location of the unexpected load. As previously mentioned, this predictive model is limited in its application as there is inaccuracy introduced by the use of data by only one test as well as simplifying assumptions. This approach makes a useful tool to quickly determine whether uncharacterized actuator loading events can damage actuation systems or induce loading that exceeds design limits.

Seetha A Kolli↗

NASA NTRS1976

Final definition and preliminary design study for the initial atmospheric cloud physics laboratory, a Spacelab mission payload

The following areas related to the final definition and preliminary design study of the initial atmospheric cloud physics laboratory (ACPL) were covered: (1) proposal organization, personnel, schedule, and project management, (2) proposed configurations, (3) study objectives, (4) ACPL experiment program listing and description, (5) mission/flight flexibility and modularity/commonality, (6) study plan, and (7) description of following tasks: requirement analysis and definition task flow, systems analysis and trade studies, subsystem analysis and trade studies, specifications and interface control documents, preliminary design task flow, work breakdown structure, programmatic analysis and planning, and project costs. Finally, an overview of the scientific requirements was presented.

Source record↗

NASA NTRS1983

Construction Equipment

FMC Corporation conducts extensive proof lift tests and computerized analysis to insure that the cranes can lift rated capacity loads up to one million pounds in a wide range of applications. In their analysis work, engineers makes use of a computer program supplied by COSMIC. Called Analysis of Beam Columns, the program is used as part of the required analysis for determining bending moments, deflections and critical load for latticed crane booms.

Source record↗

DOE OSTI2024

Sierra/SD – Theory Manual – 5.22

Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Sierra/SD. For a more detailed description of how to use Sierra/SD, we refer the reader to User’s Manual. Many of the constructs in Sierra/SD are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Sierra/SD are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer_notes manual, the user’s notes and of course the material in the open literature.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2025

Sierra/SD – Theory Manual (V.5.24)

42 ENGINEERING↗

NASA NTRS1975

User requirements and user acceptance of current and next-generation satellite mission and sensor complement, oriented toward the monitoring of water resources

Principal water resources users were surveyed to determine the applicability of remotely sensed data to their present and future requirements. Analysis of responses was used to assess the levels of adequacy of LANDSAT 1 and 2 in fulfilling hydrological functions, and to derive systems specifications for future water resources-oriented remote sensing satellite systems. The analysis indicates that water resources applications for all but the very large users require: (1) resolutions on the order of 15 meters, (2) a number of radiometric levels of the same order as currently used in LANDSAT 1 (64), (3) a number of spectral bands not in excess of those used in LANDSAT 1, and (4) a repetition frequency on the order of 2 weeks. The users had little feel for the value of new sensors (thermal IR, passive and active microwaves). What is needed in this area is to achieve specific demonstrations of the utility of these sensors and submit the results to the users to evince their judgement.

Castruccio, P. A.↗

NASA NTRS1979

Development of Integrated Programs for Aerospace-Vehicle Design (IPAD) - IPAD user requirements

Results of a requirements analysis task for Integrated Programs for Aerospace Vehicle Design (IPAD) are presented. User requirements which, in part, will shape the IPAD system design are given. Requirements considered were: generation, modification, storage, retrieval, communication, reporting, and protection of information. Data manipulation and controls on the system and the information were also considered. Specific needs relative to the product design process are also discussed.

Anderton, G. L.↗

NASA NTRS2003

Aeroservoelastic Model Validation and Test Data Analysis of the F/A-18 Active Aeroelastic Wing

Model validation and flight test data analysis require careful consideration of the effects of uncertainty, noise, and nonlinearity. Uncertainty prevails in the data analysis techniques and results in a composite model uncertainty from unmodeled dynamics, assumptions and mechanics of the estimation procedures, noise, and nonlinearity. A fundamental requirement for reliable and robust model development is an attempt to account for each of these sources of error, in particular, for model validation, robust stability prediction, and flight control system development. This paper is concerned with data processing procedures for uncertainty reduction in model validation for stability estimation and nonlinear identification. F/A-18 Active Aeroelastic Wing (AAW) aircraft data is used to demonstrate signal representation effects on uncertain model development, stability estimation, and nonlinear identification. Data is decomposed using adaptive orthonormal best-basis and wavelet-basis signal decompositions for signal denoising into linear and nonlinear identification algorithms. Nonlinear identification from a wavelet-based Volterra kernel procedure is used to extract nonlinear dynamics from aeroelastic responses, and to assist model development and uncertainty reduction for model validation and stability prediction by removing a class of nonlinearity from the uncertainty.

Brenner, Martin J.↗