SEARCH · Search NASA

Results for “generic programming”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41

All sources NASA NTRS DOE OSTI

NASA NTRS1999

Data Reduction Methods Applied to the Fastrac Engine

The Fastrac rocket engine is currently being developed for the X-34 technology demonstrator vehicle. The engine performance model must be calibrated to support accurate performance prediction. Data reduction is the process of estimating hardware characteristics from available test data, and is essential for effective performance model calibration and prediction. A new data reduction procedure was developed, implemented, and tested using data from Fastrac engine tests. The procedure selects hardware and test measurements to use in the reduction process based on examination of the model influence matrix condition number. Predicted hardware characteristics are recovered from the solution of a quadratic programming problem. Computational tests indicate that the new procedure provides a significant improvement in test data reduction capability. Enhancements include improved test data utilization and time history data reduction capability. The new method is generically applicable to other systems.

Santi, L. Michael↗

NASA NTRS1981

Reliability analysis of the F-8 digital fly-by-wire system

The F-8 Digital Fly-by-Wire (DFBW) flight test program intended to provide the technology for advanced control systems, giving aircraft enhanced performance and operational capability is addressed. A detailed analysis of the experimental system was performed to estimated the probabilities of two significant safety critical events: (1) loss of primary flight control function, causing reversion to the analog bypass system; and (2) loss of the aircraft due to failure of the electronic flight control system. The analysis covers appraisal of risks due to random equipment failure, generic faults in design of the system or its software, and induced failure due to external events. A unique diagrammatic technique was developed which details the combinatorial reliability equations for the entire system, promotes understanding of system failure characteristics, and identifies the most likely failure modes. The technique provides a systematic method of applying basic probability equations and is augmented by a computer program written in a modular fashion that duplicates the structure of these equations.

Brock, L. D.↗

NASA NTRS1986

Composite structural materials

Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

Loewy, R.↗

NASA NTRS1990

Overview of the subsonic propulsion technology session

NASA is conducting aeronautical research over a broad range of Mach numbers. In addition to the generic and high speed propulsion research, the Lewis Research Center is continuing its substantial efforts towards propulsion technology for a broad range of subsonic flight applications. Reviewed here are some of the elements of that program, including small engine technology, rotorcraft, icing research, hot section technology, and the Advanced Turboprop Project.

Sievers, G. Keith↗

NASA NTRS1990

Residual strength of repaired graphite/epoxy laminates after 5 years of outdoor exposure

The NASA Langley Research Center has sponsored research to develop generic repair techniques and processes for advanced graphite/epoxy (Gr/Ep) composites applicable to secondary structures for commercial transport aircraft. The long-term durability of such repairs is being addressed in a 10-year outdoor exposure program at the Langley Research Center. Details of the program and results of residual strength tests after 5 years of outdoor exposure are presented. Four repair methods are being evaluated. These include: (1) externally bolted aluminum-plus adhesive; (2) precured, bonded external Gr/Ep; (3) cure-in-place external Gr/Ep; and (4) cure-in-place flush Gr/Ep. Repaired specimens as well as undamaged and damaged unrepaired controls are being exposed outdoors for 1, 3, 5, 7, and 10 years. The residual tensile strength of stressed, unstressed, and fatigue specimens from each group is reported and compared with the tensile strength of baseline specimens which received no outdoor exposure. Identification of the commercial products and companies is used to describe adequately the test materials. The identification of these commercial products does not constitute endorsement, expressed or implied, of such products by the National Aeronautics and Space Administration.

Deaton, Jerry W.↗

NASA NTRS1991

Design and implementation of Ada programs to facilitate automated testing

An automated method utilized to test the software components of COMPASS, an interactive computer aided scheduling system, is presented. Each package of this system introduces a private type, and works to construct instances of that type, along with read and write routines for that type. Generic procedures that can generate test drivers for these functions are given and show how the test drivers can read from a test data file the functions to call, the arguments for those functions, what the anticipated result should be, and whether an exception should be raised for the function given the arguments.

Dean, Jack↗

NASA NTRS2007

Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Structure

Comparative studies were performed on the heat-shielding characteristics of honeycomb-core sandwich panels fabricated with different materials for possible use as wall panels for the proposed crew exploration vehicle. Graphite/epoxy sandwich panel was found to outperform aluminum sandwich panel under the same geometry due to superior heat-shielding qualities and lower material density. Also, representative reentry heat-transfer analysis was performed on the windward wall structures of a generic crew exploration vehicle. The Apollo low Earth orbit reentry trajectory was used to calculate the reentry heating rates. The generic crew exploration vehicle has a graphite/epoxy composite honeycomb sandwich exterior wall and an aluminum honeycomb sandwich interior wall, and is protected with the Apollo thermal protection system ablative material. In the thermal analysis computer program used, the TPS ablation effect was not yet included; however, the results from the nonablation heat-transfer analyses were used to develop a "virtual ablation" method to estimate the ablation heat loads and the thermal protection system recession thicknesses. Depending on the severity of the heating-rate time history, the virtual ablation period was found to last for 87 to 107 seconds and the ablation heat load was estimated to be in the range of 86 to 88 percent of the total heat load for the ablation time period. The thermal protection system recession thickness was estimated to be in the range of 0.08 to 0.11 inches. For the crew exploration vehicle zero-tilt and 18-degree-tilt stagnation points, thermal protection system thicknesses of h = {0.717, 0.733} inches were found to be adequate to keep the substructural composite sandwich temperature below the limit of 300 F.

Ko, William L.↗

NASA NTRS2007

ShareSync: A Solution for Deterministic Data Sharing over Ethernet

As part of upgrading the Contact Dynamics Simulation Laboratory (CDSL) at the NASA Marshall Space Flight Center (MSFC), a simple, cost effective method was needed to communicate data among the networked simulation machines and I/O controllers used to run the facility. To fill this need and similar applicable situations, a generic protocol was developed, called ShareSync. ShareSync is a lightweight, real-time, publish-subscribe Ethernet protocol for simple and deterministic data sharing across diverse machines and operating systems. ShareSync provides a simple Application Programming Interface (API) for simulation programmers to incorporate into their code. The protocol is compatible with virtually all Ethernet-capable machines, is flexible enough to support a variety of applications, is fast enough to provide soft real-time determinism, and is a low-cost resource for distributed simulation development, deployment, and maintenance. The first design cycle iteration of ShareSync has been completed, and the protocol has undergone several testing procedures including endurance and benchmarking tests and approaches the 2001ts data synchronization design goal for the CDSL.

Dunn, Daniel J., II↗

NASA NTRS2011

Processing of Antarctic Meteorites at NASA/Johnson Space Center

Since the beginning of the Antarctic Search for Meteorites (ANSMET) program in 1976, over 18,000 meteorites have been processed in the Meteorite Processing Lab at Johnson Space Center in Houston, TX. The first step is to renumber the meteorites from field tag number to generic number and log all the information into the meteorite database. Initial processing involves drying the meteorites in a nitrogen glove box for 24 to 48 hours, photographing, measuring, weighing and writing an exterior description. Next step is to break the meteorite and obtain a good representative sample that will be sent to the Smithsonian institution for classification. Once all the processing is done and the meteorites have been classified, the information is published in the Antarctic meteorite newsletter. The newsletter is published twice yearly and is sent electronically to researchers around the world and is also available on line. Researchers are asked to fill out a request form. The bulk of this paper relates to the researcher's request for meteorite samples.

Satterwhite, C. E.↗

NASA NTRS1995

STS-69 Flight Day 6 Highlights

After being awakened by the Beatles song, 'A Hard Days Night', the flightcrew of the STS-69 mission, Cmdr. Dave Walker, Pilot Ken Cockrell, and Mission Specialists Jim Voss, Jim Newman, and Mike Gernhardt, began their sixth day in orbit by monitoring the free orbiting Wake Shield Facility (WSF). Later Cmdr. Walker conducted an interview with television reporters from Atlanta and Boston, answering questions about the mission and general questions about NASA's space program. The crew filmed a video for themselves performing daily routines (eating, shaving, exercising), as well as some of the physiological experiments, and shuttle equipment maintenance and checkout. One of the secondary experiments included the Commercial Generic Bioprocessing Apparatus-7 (CGBA-7), which served as an incubator and experiment station for a variety of tests (agricultural, pharmaceutical, biomedical, and environmental). Earth views included some cloud cover, the Gulf of Mexico, Texas, and the Atlantic Ocean.

Source record↗

DOE OSTI2020

M4SF-20LL010301042: Updated Thermodynamic Database for Use in Generic Disposal System Assessment

This progress report (Level 4 Milestone Number M4SF-20LL010301042) summarizes research conducted at Lawrence Livermore National Laboratory (LLNL) within the Argillite Activity Number SF-20LL010301041. LLNL is leading efforts in the development of thermodynamic databases in support of the Spent Fuel and Waste Science Technology (SFWST) program. Thermodynamic models provide the basis for understanding the stability of solid phases and speciation of aqueous species and modeling the evolution of repository conditions. The LLNL effort is being performed in coordination with other US database development efforts. The effort includes a review of available thermochemical databases and a path forward for database integration. International coordination with the NEA-TDB is supported through crystalline international work package.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1984

Ground-simulation investigation of VTOL instrument flight rules airworthiness criteria

A two-part ground-simulation investigation of VTOL terminal-area operations, conducted as part of a joint NASA/FAA program to develop airworthiness criteria for this class of vehicle, is described. The baseline vehicle selected for the simulations was a generalized version of the XV-15 tilt-rotor mathematical model, which was modified to permit generic variations in forces or moments or both with power or configuration changes. Additionally, changes to wing area and rotor-blade chord were considered as a means of modifying the allowable thrust-angle versus speed relationships (the conversion corridor). The Vertical Motion Simulator at Ames Research Center was used in the experiment. Four engineering test pilots conducted over 200 piloted evaluations examining the influence of the experimental variables on their ability to perform terminal-area operations.

Lebacqz, J. V.↗

NASA NTRS1985

Users guide: The LaRC human-operator-simulator-based pilot model

A Human Operator Simulator (HOS) based pilot model has been developed for use at NASA LaRC for analysis of flight management problems. The model is currently configured to simulate piloted flight of an advanced transport airplane. The generic HOS operator and machine model was originally developed under U.S. Navy sponsorship by Analytics, Inc. and through a contract with LaRC was configured to represent a pilot flying a transport airplane. A version of the HOS program runs in batch mode on LaRC's (60-bit-word) central computer system. This document provides a guide for using the program and describes in some detail the assortment of files used during its operation.

Bogart, E. H.↗

NASA NTRS1986

Controls, health assessment, and conditional monitoring for large, reusable, liquid rocket engines

Past and future progress in the performance of control systems for large, liquid rocket engines typified such as current state-of-the-art, the Shuttle Main Engine (SSME), is discussed. Details of the first decade of efforts, which culminates in the F-1 and J-2 Saturn engines control systems, are traced, noting problem modes and improvements which were implemented to realize the SSME. Future control system designs, to accommodate the requirements of operation of engines for a heavy lift launch vehicle, an orbital transfer vehicle and the aerospace plane, are summarized. Generic design upgrades needed include an expanded range of fault detection, maintenance as-needed instead of as-scheduled, reduced human involvement in engine operations, and increased control of internal engine states. Current NASA technology development programs aimed at meeting the future control system requirements are described.

Cikanek, H. A., III↗

NASA NTRS1991

Global change technology initiative architecture trade study plan

The overall objective of the trade study is to define the architectural mix of missions, spacecraft/platforms, and sensors to meet the science requirements of the Mission to Planet Earth/Global Change Technology Initiative (MPE/GCTI) beyond the early Earth Observing System (Eos) and Geosynchronous Earth Orbit (GEO) spacecraft missions. Within the overall objective, the study includes the following specific objectives: (1) Substantiate the selected mix of Low Earth Orbit (LEO), GEO, or intermediate orbit spacecraft/platforms; (2) Define the required number and size of spacecraft related to objective (1); (3) Define a generic sensor complement for the spacecraft/platforms; (4) Evaluate current spacecraft capabilities to meet the mission requirements and develop conceptual designs of spacecraft/platforms as required. (5) Identify advanced or new technology needed to most efficiently accomplish the MPE/GCTI Program.

Source record↗

NASA NTRS1992

Khoros software specification format and interoperability

Khoros defines formats for User Interface Specification (UIS) and Program Specification (PS) files. From such files, its code generator, Ghostwriter, creates source files and documentation. The great advantage of the system is that the code fragments that make up part of the PS file are purely generic. All Khoros-related code is created by the code generator; this includes all user interface code. As a matter of fact, both specification files are very generic in nature. Thus, one could imagine using it as the basis for other software systems. A case is made that writing a code generator that would create IRAF-compatible code from the Khoros UIS and PS files is fairly trivial. Another aspect of the Khoros system conventions concerns the way execution commands are generated by the user interface and the actual syntax of those commands. The protocols are such that interoperability at the level of executable modules is readily possible.

Rots, A. H.↗

NASA NTRS2001

Discrete-State Simulated Annealing For Traveling-Wave Tube Slow-Wave Circuit Optimization

Algorithms based on the global optimization technique of simulated annealing (SA) have proven useful in designing traveling-wave tube (TWT) slow-wave circuits for high RF power efficiency. The characteristic of SA that enables it to determine a globally optimized solution is its ability to accept non-improving moves in a controlled manner. In the initial stages of the optimization, the algorithm moves freely through configuration space, accepting most of the proposed designs. This freedom of movement allows non-intuitive designs to be explored rather than restricting the optimization to local improvement upon the initial configuration. As the optimization proceeds, the rate of acceptance of non-improving moves is gradually reduced until the algorithm converges to the optimized solution. The rate at which the freedom of movement is decreased is known as the annealing or cooling schedule of the SA algorithm. The main disadvantage of SA is that there is not a rigorous theoretical foundation for determining the parameters of the cooling schedule. The choice of these parameters is highly problem dependent and the designer needs to experiment in order to determine values that will provide a good optimization in a reasonable amount of computational time. This experimentation can absorb a large amount of time especially when the algorithm is being applied to a new type of design. In order to eliminate this disadvantage, a variation of SA known as discrete-state simulated annealing (DSSA), was recently developed. DSSA provides the theoretical foundation for a generic cooling schedule which is problem independent, Results of similar quality to SA can be obtained, but without the extra computational time required to tune the cooling parameters. Two algorithm variations based on DSSA were developed and programmed into a Microsoft Excel spreadsheet graphical user interface (GUI) to the two-dimensional nonlinear multisignal helix traveling-wave amplifier analysis program TWA3. The algorithms were used to optimize the computed RF efficiency of a TWT by determining the phase velocity profile of the slow-wave circuit. The mathematical theory and computational details of the DSSA algorithms will be presented and results will be compared to those obtained with a SA algorithm.

Wilson, Jeffrey D.↗

NASA NTRS2008

Transport Aircraft System Identification from Wind Tunnel Data

Recent studies have been undertaken to investigate and develop aerodynamic models that predict aircraft response in nonlinear unsteady flight regimes for transport configurations. The models retain conventional static and rotary dynamic terms but replace conventional acceleration terms with more general indicial functions. In the Integrated Resilient Aircraft Controls project of the NASA Aviation Safety Program one aspect of the research is to apply these current developments to transport configurations to facilitate development of advanced controls technology. This paper describes initial application of a more general modeling methodology to the NASA Langley Generic Transport Model, a sub-scale flight test vehicle.

Murphy, Patrick C.↗