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At least 91 records · Page 5

Proving the correctness of a flight-director program for an airborne minicomputer

Program verification procedures are described and used to determine the correctness of a program written for an airborne computer. The basic method relies on the inductive assertion method of Floyd (1967), modified and extended for application to a machine-language situation. Correctness considerations in the flight director program include self-modification, system correctness, executable instructions, overflow, approximate calculations with fractional quantities, and fixed point scaling. An example proof of correctness, which proceeds by proving the correctness of a certain subroutine, is provided.

Maurer, W. D.↗

A pilot training manual for the terminal configured vehicle electronic attitude director indicator

A hard copy version is presented of a 28-minute, 90 slide audiovisual program which provides the basic instructional format for introduction to the terminal configured vehicle electronic attitude director indicator (EADI) and the strategy for learning the symbols used on the EADI and their interpretation. The basic strategy is to start with known symbols and then introduce all new symbols with emphasis appropriate to their complexity and frequency of use. The upper half of each page of the manual contains a reproduction of the slide. The text associated with the slide is found on the lower half of each page and is recorded on audio tape.

Gandelman, J.↗

Low loss injector for Space Shuttle main engine. Center director's discretionary fund

An efficient propellant injection method to raise the Space Shuttle Main Engine (SSME) thrust and payload is discussed. Relatively large diameter injector elements with low pressure loss are recommended for the main combustion chamber and the pre-burners. Smaller losses admit more propellant flow which then raises thrust. Payload is not only gained by specific impulse but also by thrust. The chamber pressure is stabilized by selecting the proper cavity size for the injector elements while reducing the injection pressure loss which normally is kept high for stability. The rather large injector element recesses provide acoustic damping which makes baffles and acoustic absorbers unnecessary. A tenfold reduction of flow induced stresses which are rather high in the present design is shown. Relaxed tolerances, fewer elements, and better maintenance are offered. The study was conducted under a center director discretionary fund assignment.

Vonpragenau, G. L.↗

Investigations carried out under the Director's Discretionary Fund

This annual report comprises a set of summaries, describing task objectives, progress and results or accomplishments, future outlook, and financial status for each director's discretionary fund (DDF) task that was active during fiscal year 1984. Publications and conference presentations related to the work are listed. The individual reports are categorized as interim or final according to whether the task efforts are ongoing or completed. A partial list of new tasks to be initiated with fiscal year 1985 funds and a glossary of abbreviations and acronyms, used by the task authors in their summaries are included. The table of contents lists the DDF reports in sequence by their task number, which is derived from the 13-digit code assigned to account for the fund awarded to the task project.

Chahine, M. T.↗

User's operating procedures. Volume 3: Projects directorate information programs

A review of the user's operating procedures for the scout project automatic data system, called SPADS is presented. SPADS is the results of the past seven years of software development on a prime mini-computer. SPADS was developed as a single entry, multiple cross-reference data management and information retrieval system for the automation of Project office tasks, including engineering, financial, managerial, and clerical support. This volume, three of three, provides the instructions to operate the projects directorate information programs in data retrieval and file maintenance via the user friendly menu drivers.

Haris, C. G.↗

Space directorate research and technology accomplishments for fiscal year 1987

The major accomplishments and test highlights of the Space Directorate of NASA Langley Research Center for FY87 are presented. Accomplishments and test highlights are listed by Division and Branch. This information should be useful in coordinating programs with government organizations, universities, and industry in areas of mutual interest.

Avery, Don E.↗

Mission Operations and Data Systems Directorate's operational/development network (MODNET) at Goddard Space Flight Center

A brief, informal narrative is provided that summarizes the results of all work accomplished during the period of the contract; June 1, 1987 through September 30, 1988; in support of Mission Operations and Data Systems Directorate's Operational Development Network (MODNET). It includes descriptions of work performed in each functional area and recommendations and conclusions based on the experience and results obtained.

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A review and forecast of engine system research at the Army Propulsion Directorate

An account is given of the development status and achievements to date of the U.S. Army Propulsion Directorate's Small Turbine Engine Research (STER) programs, which are experimental investigations of the physics of entire engine systems from the viewpoints of component interactions and/or system dynamics. STER efforts are oriented toward the evaluation of complete turboshaft engine advanced concepts and are conducted at the ECRL-2 indoor, sea-level engine test facility. Attention is given to the results obtained by STER experiments concerned with IR-suppressing engine exhausts, a ceramic turbine-blade shroud, an active shaft-vibration control system, and a ceramic-matrix combustor liner.

Bobula, George A.↗

JSC director's discretionary fund program

The Johnson Space Center Director's Discretionary Fund Program Annual Report provides a brief review of the status of projects undertaken during the 1990 fiscal year. Three space exploration initiative related issues were focused on: regenerative life support, human spacecraft design, and lunar surface habitat. A viable program of life sciences, space sciences, and engineering research has been maintained.

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An analysis of Space Shuttle countdown activities: Preliminaries to a computational model of the NASA Test Director

Before all systems are go just prior to the launch of a space shuttle, thousands of operations and tests have been performed to ensure that all shuttle and support subsystems are operational and ready for launch. These steps, which range from activating the orbiter's flight computers to removing the launch pad from the itinerary of the NASA tour buses, are carried out by launch team members at various locations and with highly specialized fields of expertise. The liability for coordinating these diverse activities rests with the NASA Test Director (NTD) at NASA-Kennedy. The behavior is being studied of the NTD with the goal of building a detailed computational model of that behavior; the results of that analysis to date are given. The NTD's performance is described in detail, as a team member who must coordinate a complex task through efficient audio communication, as well as an individual taking notes and consulting manuals. A model of the routine cognitive skill used by the NTD to follow the launch countdown procedure manual was implemented using the Soar cognitive architecture. Several examples are given of how such a model could aid in evaluating proposed computer support systems.

John, Bonnie E.↗

An Introduction to Intelligent Processing Programs Developed by the Air Force Manufacturing Technology Directorate

The Air Force has numerous on-going manufacturing and integration development programs (machine tools, composites, metals, assembly, and electronics) which are instrumental in improving productivity in the aerospace industry, but more importantly, have identified strategies and technologies required for the integration of advanced processing equipment. An introduction to four current Air Force Manufacturing Technology Directorate (ManTech) manufacturing areas is provided. Research is being carried out in the following areas: (1) machining initiatives for aerospace subcontractors which provide for advanced technology and innovative manufacturing strategies to increase the capabilities of small shops; (2) innovative approaches to advance machine tool products and manufacturing processes; (3) innovative approaches to advance sensors for process control in machine tools; and (4) efforts currently underway to develop, with the support of industry, the Next Generation Workstation/Machine Controller (Low-End Controller Task).

Sampson, Paul G.↗

Director's discretionary fund report for FY 1991

The Director's Discretionary Fund (DDF) at the Ames Research Center was established to fund innovative, high-risk projects in basic research which would otherwise be difficult to initiate, but which are essential to our future programs. Here, summaries are given of individual projects within this program. Topics covered include scheduling electric power for the Ames Research Center, the feasibility of light emitting diode arrays as a lighting source for plant growth chambers in space, plasma spraying of nonoxide coatings using a constricted arcjet, and the characterization of vortex impingement footprint using non-intrusive measurement techniques.

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Development of a large field-of-view KD potassium di-deuterium phosphate modulator: Center Director's Discretionary Fund

Magnetographs, which measure polarized light, allow solar astronomers to infer the magnetic field intensity on the Sun. The Marshall Space Flight Center (MSFC) Vector Magnetograph is such an imaging instrument. The instrument requires rapid modulation between polarization states to minimize seeing effects. The accuracy of those polarization measurements is dependent on stable modulators with small field-of-view errors. Although these devices are very important in ground-based telescopes, extending the field of view of electro-optical crystals such as KD*Ps (potassium di-deuterium phosphate) could encourage the development of these devices for other imaging applications. The work that was done at MSFC as part of the Center Director's Discretionary Fund (CDDF) to reduce the field-of-view errors of instruments that use KD*P modulators in their polarimeters is described.

West, E. A.↗

Director's discretionary fund

This technical memorandum contains brief technical papers describing research and technology development programs sponsored by the ARC Director's Discretionary Fund during fiscal year 1992 (Oct. 1991 through Sep. 1992). An appendix provides administrative information for each of the 45 sponsored research programs.

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Director's Discretionary Fund report for FY 1993

This technical memorandum contains brief technical papers describing research and technology development programs sponsored by the Ames Research Center Director's Discretionary Fund during fiscal year 1993 (October 1992 through September 1993). An appendix provides administrative information for each of the sponsored research programs.

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Director's discretionary fund report for fiscal year 1994

This technical memorandum contains brief technical papers describing research and technology development programs sponsored by the Ames Research Center Director's Discretionary Fund during fiscal year 1991 (October 1993 through September 1994). An appendix provides administrative information for each of the sponsored research programs.

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Review of Our National Heritage of Launch Vehicles Using Aerodynamic Surfaces and Current Use of These by Other Nations: Center Director's Discretionary Fund Project Numbe - Part II

Marshall Space Flight Center has a rich heritage of launch vehicles that have used aerodynamic surfaces for flight stability and for flight control. Recently, due to the aft center-of-gravity (cg) locations on launch vehicles currently being studied, the need has arisen for the vehicle control augmentation that can be provided by these flight controls. Aerodynamic flight control can also reduce engine gimbaling requirements, provide actuator failure protection, enhance crew safety, and increase vehicle reliability and payload capability. As a starting point for the novel design of aerodynamic flight control augmentors for a Saturn class, aft cg launch vehicle, this report undertakes a review of our national heritage of launch vehicles using aerodynamic surfaces, along with a survey of current use of aerodynamic surfaces on large launch vehicles of other nations. This report presents one facet of Center Director's Discretionary Fund Project 93-05 and has a previous and subsequent companion publication.

Barret, C.↗

Directors's Discretionary Fund Report For Fiscal Year 1995

This technical memorandum contains brief technical papers describing research and technology development programs sponsored by the Ames Research Center Director's Discretionary Fund during the fiscal year 1995 (October 1994 through September 1995). An appendix provides administrative information for each of the sponsored research programs.

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