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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 649 records · Page 36

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NASA NTRS1978

Payload integration and operations

Integration and operation of Spacelab payloads presents major challenges to engineering disciplines in areas of ground operations and flight mission operations. The integration of ground operations encompasses activities performed by the instrument developers and principal investigators and by the centralized payload integration site and launch site. The payload will be operated on orbit by a payload crew trained in payload experimentation and by a payload operations control center where investigator science groups and operations personnel are prepared to provide support. The payload mission planning, control center, data processing facility and operations are developed and verified prior to realtime flight operations. The mission management approach to minimize program costs and impacts to payloads and the Space Transportation System/Spacelab accommodations is presented.

Hall, R. R.↗

NASA NTRS1980

Multigigabit satellite on-board signal processing

The satellite communication system described provides communications for very small and very large (trunking) users. Independent combinations of FDMA and TDMA are used in the uplink and downlink designs to minimize terminal costs. Signal routing for small users is accomplished by a digital store-and-forward technique which greatly simplifies the terminal receiver, compared to satellite-switched TDMA. Different processing techniques are used for very high data rate users, but complete interconnectivity between all users is maintained. This avoids double-hop routing with excessive transmission delays.

Holmes, W. M., Jr.↗

NASA NTRS1980

HiMAT systems development results and projections

Significant findings of the Highly Maneuverable Aircraft Technology Remotely Piloted Research Vehicle (HiMAT RPRV) flight test program are presented. Among the topics covered are: aerodynamic scaling relationships, the aeroelastic tailoring of wing and canard twist and camber, and laminate graphite/epoxy composite primary structure performance under high-g loading maneuvers. Attention is also given to the set of actuators used in the test and development program, with a view to the minimization of costs through modularity and interchangeability of components and the extensive use of off-the-shelf equipment. The relationship between composite ply geometry and the shape and magnitude of aeroelastic deformations during maneuvering is discussed in detail.

Brown, L. E., Jr.↗

NASA NTRS1982

Use of optimization to predict the effect of selected parameters on commuter aircraft performance

An optimizing computer program determined the turboprop aircraft with lowest direct operating cost for various sets of cruise speed and field length constraints. External variables included wing area, wing aspect ratio and engine sea level static horsepower; tail sizes, climb speed and cruise altitude were varied within the function evaluation program. Direct operating cost was minimized for a 150 n.mi typical mission. Generally, DOC increased with increasing speed and decreasing field length but not by a large amount. Ride roughness, however, increased considerably as speed became higher and field length became shorter.

Wells, V. L.↗

NASA NTRS1982

Cryogenic orbit transfer vehicle

Studies determined that shuttle optimized design, allowing the large space system and transfer vehicle in one shuttle flight, greatly reduces transportation costs and minimizes orbital operations. Careful attention to design resulted in efficient payload packaging. A minimum volume, high energy (liquid oxygen and liquid hydrogen) transfer vehicle is described that allows maximum volume for the payload in the orbiter cargo bay.

Ketchum, W. J.↗

NASA NTRS1982

Programmable controller system for wind tunnel diversion vanes

A programmable controller (PC) system automatic sequence control, which acts as a supervisory controller for the servos, selects the proper drives, and automatically sequences the vanes, was developed for use in a subsonic wind tunnel. Tunnel modifications include a new second test section (80 ft x 100 ft with a maximum air speed capability of 110 knots) and an increase in maximum velocity flow from 200 knots to 300 knots. A completely automatic sequence control is necessary in order to allow intricate motion of the 14 triangularly arranged vanes which can be as large as 70 ft high x 35 ft wide and which require precise acceleration and deceleration control. Rate servos on each drive aid in this control, and servo cost was minimized by using four silicon controlled rectifier controllers to control the 20 dc drives. The PC has a programming capacity which facilitated the implementation of extensive logic design. A series of diagrams sequencing the vanes and a block diagram of the system are included.

King, R. F.↗

NASA NTRS1982

The elements of a space operations system

The Space Shuttle has completed its flight test program and is entering operational service with its fifth flight in November 1982. With the completion of Shuttle development, its entry to operational service, and delivery of additional units into field service, it is timely to initiate development of the next elements of the system. The elements of a Space Operations System are the Shuttle, a Station in low earth orbit, and upper stages for low and high energy orbit delivery. To design these elements properly will require a substantial operations analysis effort to characterize the most effective performance tradeoffs among the discrete elements. The Shuttle establishes a new context for the design and execution of operations in space. The components of the Shuttle, Space Station, and upper stages will need to share technology and components to minimize the cost and complexity of the logistics of ownership and operation.

Loftus, J. P., Jr.↗

NASA NTRS1982

The Ruggedized STD Bus Microcomputer - A low cost computer suitable for Space Shuttle experiments

Previous space flight computers have been costly in terms of both hardware and software. The Ruggedized STD Bus Microcomputer is based on the commercial Mostek/Pro-Log STD Bus. Ruggedized PC cards can be based on commercial cards from more than 60 manufacturers, reducing hardware cost and design time. Software costs are minimized by using standard 8-bit microprocessors and by debugging code using commercial versions of the ruggedized flight boards while the flight hardware is being fabricated.

Budney, T. J.↗

NASA NTRS1982

Antenna optimization of single beam microwave systems for the solar power satellite

A generalized antenna design technique is applied to the unique environmental requirements pertaining to solar power satellite (SPS) systems. Optimal illumination tapers and antenna/rectenna sizings are generated which allow increased transmit powers and lower electricity costs while minimizing sidelobe levels to meet a 0.01 mW/sq cm environmental standard. These optimal tapers also provide other advantages over the 10 dB Gaussian reference system.

Kerwin, E. M.↗

NASA NTRS1983

Implementation Strategy

Meeting the identified needs of Earth science requires approaching EOS as an information system and not simply as one or more satellites with instruments. Six elements of strategy are outlined as follows: implementation of the individual discipline missions as currently planned; use of sustained observational capabilities offered by operational satellites without waiting for the launch of new mission; put first priority on the data system; deploy an Advanced Data Collection and Location System; put a substantial new observing capability in a low Earth orbit in such a way as to provide for sustained measurements; and group instruments to exploit their capabilities for synergism; maximize the scientific utility of the mission; and minimize the costs of implementation where possible.

Source record↗

NASA NTRS1985

The application of artificial intelligence techniques to large distributed networks

Data accessibility and transfer of information, including the land resources information system pilot, are structured as large computer information networks. These pilot efforts include the reduction of the difficulty to find and use data, reducing processing costs, and minimize incompatibility between data sources. Artificial Intelligence (AI) techniques were suggested to achieve these goals. The applicability of certain AI techniques are explored in the context of distributed problem solving systems and the pilot land data system (PLDS). The topics discussed include: PLDS and its data processing requirements, expert systems and PLDS, distributed problem solving systems, AI problem solving paradigms, query processing, and distributed data bases.

Dubyah, R.↗

NASA NTRS1984

Optimal inventories for overhaul of repairable redundant systems - A Markov decision model

A Markovian decision model was developed to calculate the optimal inventory of repairable spare parts for an avionics control system for commercial aircraft. Total expected shortage costs, repair costs, and holding costs are minimized for a machine containing a single system of redundant parts. Transition probabilities are calculated for each repair state and repair rate, and optimal spare parts inventory and repair strategies are determined through linear programming. The linear programming solutions are given in a table.

Schaefer, M. K.↗

NASA NTRS1985

Application of modern tools and techniques to maximize engineering productivity in the development of orbital operations plans for the space station progrm

The Space Station Program will incorporate analysis of operations constraints and considerations in the early design phases to avoid the need for later modifications to the Space Station for operations. The application of modern tools and administrative techniques to minimize the cost of performing effective orbital operations planning and design analysis in the preliminary design phase of the Space Station Program is discussed. Tools and techniques discussed include: approach for rigorous analysis of operations functions, use of the resources of a large computer network, and providing for efficient research and access to information.

Manford, J. S.↗

NASA NTRS1986

Integration of an expert system into a user interface language demonstration

The need for a User Interface Language (UIL) has been recognized by the Space Station Program Office as a necessary tool to aid in minimizing the cost of software generation by multiple users. Previous history in the Space Shuttle Program has shown that many different areas of software generation, such as operations, integration, testing, etc., have each used a different user command language although the types of operations being performed were similar in many respects. Since the Space Station represents a much more complex software task, a common user command language--a user interface language--is required to support the large spectrum of space station software developers and users. To assist in the selection of an appropriate set of definitions for a UIL, a series of demonstration programs was generated with which to test UIL concepts against specific Space Station scenarios using operators for the astronaut and scientific community. Because of the importance of expert system in the space station, it was decided that an expert system should be embedded in the UIL. This would not only provide insight into the UIL components required but would indicate the effectiveness with which an expert system could function in such an environment.

Stclair, D. C.↗

NASA NTRS1986

Electrical power system for the U.S. space station

The Space Station Electrical Power System presents many interesting challenges. It will be much larger than previous space power systems, and it must be designed for on-orbit maintenance and replacement, along with having a growth capability. The power generation, energy storage, and power management and distribution (PMAD) subsystems comprise the primary elements of the overall system. Each was analyzed by NASA Lewis Research Center and its two contractors -- Rocketdyne and TRW -- in the definition studies of the program to determine the optimum approach to minimize initial costs and life cycle costs. For the PMAD subsystem, a ring bus architecture operating at 440 V, 20 kHz, single phase, was selected. Photovoltaic and solar dynamic power generation subsystems were both studied. Major tradeoffs were made for each subsystem and for the overall system, and a hybrid system (both photovoltaic and solar dynamic) was selected.

Nored, D. L.↗

NASA NTRS1986

Electrical power system for the U.S. Space Station

The Space Station Electrical Power System presents many interesting challenges. It will be much larger than previous space power systems, and it must be designed for on-orbit maintenance and replacement, along with having a growth capability. The power generation, energy storage, and power management and distribution (PMAD) subsystems comprise the primary elements of the overall system. Each was analyzed by NASA Lewis Research Center and its two contractors Rocketdyne and TRW - in the definition studies of the program to determine the optimum approach to minimize initial costs and life cycle costs. For the PMAD subsystem, a ring bus architecture operating at 440 V, 20 kHz, single phase, was selected. Photovoltaic and solar dynamic power generation subsystems were both studied. Major tradeoffs were made for each subsystem and for the overall system, and a hybrid system (both photovoltaic and solar dynamic) was selected.

Nored, D. L.↗

NASA NTRS1986

Affordable solar system exploration

The design features of the Comet Rendezvous Asteroid Flyby (CRAF) version of the Mariner Mark II spacecraft are described, together with the instruments to be carried aboard and the goals of the mission. To minimize the cost, computer-aided design, engineering, and manufacturing will be used, and, where possible, established technologies and off-the- shelf products will be incorporated. Planned for a launch in 1992, the CRAF will rendezvous with the Tempel 2 comet in 1996 and will stick with it through 1999, making studies of plasma in the comet's coma and the comet's dust, gas, and nucleus by means of its penetrator rocket which will pierce the nucleus.

Draper, Ronald F.↗

NASA NTRS1987

Real-time operational planning for the U.S. air traffic system

This paper describes an integrated planning model for the U.S. air traffic system. The approach incorporates the dual objectives of monitoring collision risk while minimizing transportation costs. Specialized solution algorithms exploit the underlying structure of the model - especially for large-scale examples. The proposed formulation is tested with real-world data for the Indianapolis control sector. Additional experiments with a CRAY X-MP/24 supercomputer show that a full-scale model can be solved under real time conditions. Despite these advances, additional work is required in developing a practical system. Suggestions are made for combining advances in computer graphics and mathematical modeling.

Mulvey, John M.↗