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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Space Station Simulation Computer System (SCS) study for NASA/MSFC. Phased development plan

NASA's Space Station Freedom Program (SSFP) planning efforts have identified a need for a payload training simulator system to serve as both a training facility and as a demonstrator to validate operational concepts. The envisioned MSFC Payload Training Complex (PTC) required to meet this need will train the Space Station payload scientists, station scientists and ground controllers to operate the wide variety of experiments that will be onboard the Space Station Freedom. The Simulation Computer System (SCS) is made up of computer hardware, software, and workstations that will support the Payload Training Complex at MSFC. The purpose of this SCS Study is to investigate issues related to the SCS, alternative requirements, simulator approaches, and state-of-the-art technologies to develop candidate concepts and designs.

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NASA NTRS1991

Case for real-time systems development - Quo vadis?

The paper focuses on the distinctive issues of computer-aided software engineering (CASE) products for the development of real-time systems. CASE technologies and associated standardization efforts are evolving from sets of conflicting interests. The majority of case products are intended for use in the development of management information systems. CASE products to support the development of large, complex real-time systems must provide additional capabilities. Generic concerns include the quality of the implementation of the required method for the phase of the system's development and whether the vendor is stable and committed to evolving the products in parallel with nonproprietary standards. The CASE market is undergoing considerable consolidation. The paper describes the major forces, cooperating entities, and remaining uncertainties that need to be weighed in near-term CASE procurements to limit risk of loss of investment in project time, trianing, and money.

Erb, Dona M.↗
NASA NTRS1991

Applications of an automated programming system

A Computer-Aided Software Engineering (CASE) system has been developed at the Charles Stark Draper Laboratory (CSDL) under the direction of the NASA Langley Research Center. The Automated Programming Subsystem is the core of the CSDL CASE system. The Automated Programming Subsystem allows an engineer to describe software specifications as hierarchical engineering block diagrams, a natural design technique for the specification of real-time software. The objective of the Automated Programming Subsystem is to capture completely and consistently both logical and schematic information as diagrams are developed, and then to automatically transform this information into source code (Ada or C) and documentation. The Automated Programming Subsystem of CSDL CASE has been used on many applications, from small to moderate size. Six of these applications are described in this paper.

Walker, Carrie K.↗
NASA NTRS1989

Space Station Freedom Safety Program

The renewed emphasis within NASA on the incorporation of firmly established safety design requirements and evolving new safety analysis techniques, including quantitative safety risk assessment methods, is discussed with particular reference to the Space Station Freedom Safety Program. The program provides for integration of the partial safety analysis performed by numerous NASA Centers and International Partners into a Programmatic Safety Assessment for each of the launch increments and the complete Space Station Freedom on orbit. Communication in the safety program will utilize state-of-the-art software and computers, which will provide broad accessibility to safety information among the NASA and International Partners.

Griggs, John G., III↗
NASA NTRS1992

A timely rationale for space exploration

Space exploration is shown to be useful for enhancing a country's education, technology, and economic competitiveness. Technologies required for the Space Exploration Initiative are compared to emerging technologies identified by the U.S. Department of Commerce. The impact of previous space ventures on specific technologies are illustrated with examples such as miniaturized electronics, computers and software, and high-strength materials. The case for educational advancement as a by-product of space exploration is made by discussing the high-level requirements of the programs and describing the inspirational effect of space exploration on young students. Invigorating space exploration is argued to generate near- and long-term economic opportunities for key sectors of the national economy by means of technology transfer, space-resource utilization, and the commercialization of space.

Peterson, Douglas D.↗
NASA NTRS1993

Data On Flow About A Compressor Blade In Cascade

Development and testing of software to compute values of flow-field characteristics greatly enhanced by using recorded experimental data to test results of computations. Report "The Measurement Of Boundary Layers On Compressor Blade In Cascade" is data base providing detailed measurements of boundary layer and wake in flow field about double-circular-arc compressor blades in cascade of such blades.

Deutsch, S.↗
NASA NTRS1993

The systems engineering overview and process (from the Systems Engineering Management Guide, 1990)

The past several decades have seen the rise of large, highly interactive systems that are on the forward edge of technology. As a result of this growth and the increased usage of digital systems (computers and software), the concept of systems engineering has gained increasing attention. Some of this attention is no doubt due to large program failures which possibly could have been avoided, or at least mitigated, through the use of systems engineering principles. The complexity of modern day weapon systems requires conscious application of systems engineering concepts to ensure producible, operable and supportable systems that satisfy mission requirements. Although many authors have traced the roots of systems engineering to earlier dates, the initial formalization of the systems engineering process for military development began to surface in the mid-1950s on the ballistic missile programs. These early ballistic missile development programs marked the emergence of engineering discipline 'specialists' which has since continued to grow. Each of these specialties not only has a need to take data from the overall development process, but also to supply data, in the form of requirements and analysis results, to the process. A number of technical instructions, military standards and specifications, and manuals were developed as a result of these development programs. In particular, MILSTD-499 was issued in 1969 to assist both government and contractor personnel in defining the systems engineering effort in support of defense acquisition programs. This standard was updated to MIL-STD499A in 1974, and formed the foundation for current application of systems engineering principles to military development programs.

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NASA NTRS1993

Performance analysis of a large-grain dataflow scheduling paradigm

A paradigm for scheduling computations on a network of multiprocessors using large-grain data flow scheduling at run time is described and analyzed. The computations to be scheduled must follow a static flow graph, while the schedule itself will be dynamic (i.e., determined at run time). Many applications characterized by static flow exist, and they include real-time control and digital signal processing. With the advent of computer-aided software engineering (CASE) tools for capturing software designs in dataflow-like structures, macro-dataflow scheduling becomes increasingly attractive, if not necessary. For parallel implementations, using the macro-dataflow method allows the scheduling to be insulated from the application designer and enables the maximum utilization of available resources. Further, by allowing multitasking, processor utilizations can approach 100 percent while they maintain maximum speedup. Extensive simulation studies are performed on 4-, 8-, and 16-processor architectures that reflect the effects of communication delays, scheduling delays, algorithm class, and multitasking on performance and speedup gains.

Young, Steven D.↗
NASA NTRS1992

Astronomical CCD observing and reduction techniques

CCD instrumentation and techniques in observational astronomy are surveyed. The general topics addressed include: history of large array scientific CCD imagers; noise sources and reduction processes; basic photometry techniques; introduction to differential time-series astronomical photometry using CCDs; 2D imagery; point source spectroscopy; extended object spectrophotometry; introduction to CCD astrometry; solar system applications for CCDs; CCD data; observing with infrared arrays; image processing, data analysis software, and computer systems for CCD data reduction and analysis. (No individual items are abstracted in this volume)

Howell, Steve B.↗
NASA NTRS1988

Software engineering as an engineering discipline

The purpose of this panel is to explore the emerging field of software engineering from a variety of perspectives: university programs; industry training and definition; government development; and technology transfer. In doing this, the panel will address the issues of distinctions among software engineering, computer science, and computer hardware engineering as they relate to the challenges of large, complex systems.

Freedman, Glenn B.↗
NASA NTRS1988

Software engineering as an engineering discipline

The following topics are discussed in the context of software engineering: early use of the term; the 1968 NATO conference; Barry Boehm's definition; four requirements fo software engineering; and additional criteria for software engineering. Additionally, the four major requirements for software engineering--computer science, mathematics, engineering disciplines, and excellent communication skills--are discussed. The presentation is given in vugraph form.

Berard, Edward V.↗
NASA NTRS1993

Data collection with the ACTS propagation terminal

Viewgraphs on data collection with the ACTS propagation terminal are included. Topics covered include: DACS system overview; DACS board; APT data collection computer; APT software downloading; data storage for APT; and ACTS propagation experiment data flow.

Remaklus, Will↗
NASA NTRS1993

Proprioceptive isokinetic exercise test

Proprioception, the reception of stimuli within the body that indicates position, is an important mechanism for optimal human performance. People exposed to prolonged bed rest, microgravity, or other deconditioning situations usually experience reduced proprioceptor and kinesthetic stimuli that compromise body balance, posture, and equilibrium. A new proprioceptive test is described that utilizes the computer-driven LIDO isokinetic ergometer. An overview of the computer logic, software, and testing procedure for this proprioceptive test, which can be performed with the arms or legs, is described.

Dempster, P. T.↗
NASA NTRS1994

Design and performance/measurement simulation studies for a ER-2 sunphotometer

Work and results, including developed software, obtained under this grant (NAG 2-620) have been reported in various progress reports, an M.S. Thesis, and software programs. The purpose of this final report is simply to provide a documented listing of what has already been reported. This includes the following: (1) Conceptual Design and Simulation of a Spectral Sunphotometer for the ER-2 Aircraft; (2) Continued Simulation and Design Studies for an ER-2 Sunphotometer; and (3) Simulation and Performance Studies of a Spectra Sunphotometer for the ER-2 Aircraft. Also, software and computational results for modeling airmass and diffuse light effects due to aerosols were provided in support of NASA ARC research on the effects of aerosols resulting from the Pinatubo volcanic eruptions. The references for these articles are as follows: (1) Post Pinatubo Optical Depth Spectra vs. Latitude and Vortex Structure; and (2) Pinatubo and Pre-Pinatubo Optical-Depth Spectra -- Mauna Loa Measurements, Comparisons, Inferred Particle Size Distributions, Radiative Effects, and Relationships to Lidar Data.

Reagan, J. A.↗
NASA NTRS1995

Portable Computer Technology (PCT) Research and Development Program Phase 2

The subject of this project report, focused on: (1) Design and development of two Advanced Portable Workstation 2 (APW 2) units. These units incorporate advanced technology features such as a low power Pentium processor, a high resolution color display, National Television Standards Committee (NTSC) video handling capabilities, a Personal Computer Memory Card International Association (PCMCIA) interface, and Small Computer System Interface (SCSI) and ethernet interfaces. (2) Use these units to integrate and demonstrate advanced wireless network and portable video capabilities. (3) Qualification of the APW 2 systems for use in specific experiments aboard the Mir Space Station. A major objective of the PCT Phase 2 program was to help guide future choices in computing platforms and techniques for meeting National Aeronautics and Space Administration (NASA) mission objectives. The focus being on the development of optimal configurations of computing hardware, software applications, and network technologies for use on NASA missions.

Castillo, Michael↗
NASA NTRS1996

A Cost Comparison of Alternative Approaches to Distance Education in Developing Countries

This paper presents a cost comparison of three approaches to two-way interactive distance learning systems for developing countries. Included are costs for distance learning hardware, terrestrial and satellite communication links, and designing instruction for two-way interactive courses. As part of this project, FSEC is developing a 30-hour course in photovoltaic system design that will be used in a variety of experiments using the Advanced Communications Technology Satellite (ACTS). A primary goal of the project is to develop an instructional design and delivery model that can be used for other education and training programs. Over two-thirds of the world photovoltaics market is in developing countries. One of the objectives of this NASA-sponsored project was to develop new and better energy education programs that take advantage of advances in telecommunications and computer technology. The combination of desktop video systems and the sharing of computer applications software is of special interest. Research is being performed to evaluate the effectiveness of some of these technologies as part of this project. The design of the distance learning origination and receive sites discussed in this paper were influenced by the educational community's growing interest in distance education. The following approach was used to develop comparative costs for delivering interactive distance education to developing countries: (1) Representative target locations for receive sites were chosen. The originating site was assumed to be Cocoa, Florida, where FSEC is located; (2) A range of course development costs were determined; (3) The cost of equipment for three alternative two-way interactive distance learning system configurations was determined or estimated. The types of system configurations ranged from a PC-based system that allows instructors to originate instruction from their office using desktop video and shared application software, to a high cost system that uses a electronic classroom; (4) A range of costs for both satellite and terrestrial communications was investigated; (5) The costs of equipment and operation of the alternative configurations for the origination and receive sites were determined; (6) A range of costs for several alternative delivery scenarios (i.e., a mix of live-interactive; asynchronous interactive;use of videotapes) was determined; and (7) A preferred delivery scenario, including cost estimate, was developed.

Ventre, Gerard G.↗
NASA NTRS1997

Research to Support the Determination of Spacecraft Maximum Acceptable Concentrations of Potential Atmospheric Contaminants

In many ways, the typical approach to the handling of bibliographic material for generating review articles and similar manuscripts has changed little since the use of xerographic reproduction has become widespread. The basic approach is to collect reprints of the relevant material and place it in folders or stacks based on its dominant content. As the amount of information available increases with the passage of time, the viability of this mechanical approach to bibliographic management decreases. The personal computer revolution has changed the way we deal with many familiar tasks. For example, word processing on personal computers has supplanted the typewriter for many applications. Similarly, spreadsheets have not only replaced many routine uses of calculators but have also made possible new applications because the cost of calculation is extremely low. Objective The objective of this research was to use personal computer bibliographic software technology to support the determination of spacecraft maximum acceptable concentration (SMAC) values. Specific Aims The specific aims were to produce draft SMAC documents for hydrogen sulfide and tetrachloroethylene taking maximum advantage of the bibliographic software.

Orr, John L.↗
NASA NTRS1998

Improved instrumental magnitude prediction expected from version 2 of the NASA SKY2000 master star catalog

The SKY2000 Master Star Catalog (MC), Version 2 and its predecessors have been designed to provide the basic astronomical input data needed for satellite acquisition and attitude determination on NASA spacecraft. Stellar positions and proper motions are the primary MC data required for operations support followed closely by the stellar brightness observed in various standard astronomical passbands. The instrumental red-magnitude prediction subsystem (REDMAG) in the MMSCAT software package computes the expected instrumental color index (CI) [sensor color correction] from an observed astronomical stellar magnitude in the MC and the characteristics of the stellar spectrum, astronomical passband, and sensor sensitivity curve. The computation is more error prone the greater the mismatch of the sensor sensitivity curve characteristics and those of the observed astronomical passbands. This paper presents the preliminary performance analysis of a typical red-sensitive CCDST during acquisition of sensor data from the two Ball CT-601 ST's onboard the Rossi X-Ray Timing Explorer (RXTE). A comparison is made of relative star positions measured in the ST FOV coordinate system with the expected results computed from the recently released Tycho Catalogue. The comparison is repeated for a group of observed stars with nearby, bright neighbors in order to determine the tracker behavior in the presence of an interfering, near neighbor (NN). The results of this analysis will be used to help define a new photoelectric photometric instrumental sensor magnitude system (S) that is based on several thousand bright star magnitudes observed with the PXTE ST's. This new system will be implemented in Version 2 of the SKY2000 MC to provide improved predicted magnitudes in the mission run catalogs.

Sande, C. B.↗