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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 739 records · Page 41

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NASA NTRS1982

The detailed chemistry and thermodynamics of sodium in oxygen-rich flames

Measurement of sodium and OH concentrations in ten oxygen-rich H2/O2/N2 flames by respective saturated and low-power laser induced fluorescence techniques have permitted a detailed examination of the pronounced flame chemistry of sodium in such oxygen rich media. Previous interpretations have been shown to be largely incomplete or in error. The flame downstream profiles indicate that the amount of free sodium tracks the decay of H-atom and as the flame radicals decay sodium becomes increasingly bound in a molecular form. A detailed kinetic model indicates that the sodium is distributed between NaOH and NaO2 species. Concentrations of NaO are very small and NaH negligible. The actual distribution is controlled by the state of equilibrium of the flames' basic free radicals. Na, NaO2 and NaOH are all coupled to one another by fast reactions which can rapidly interconvert one to another as flame conditions vary. Above about 2000K, NaOH becomes dominant whereas NaO2 plays an increasingly important contribution at lower temperatures.

Hynes, A. J.↗

NASA NTRS1982

Elliptic grid generation

Various types of generating systems for boundary-conforming coordinate systems based on the numerical solution of systems of elliptic partial differential equations are discussed. Particular emphasis is given to the determination of functions in these equations which control the distribution of the curvilinear coordinate lines in the field.

Thompson, J. F.↗

NASA NTRS1984

LANDSAT-MSS multitemporal registration

The multitemporal registration of LANDSAT-4 MSS products was tested for two different geocoded subscenes acquired in 1982 and 1983. The scenes were then compared with LANDSAT-2 MSS geocoded data from 1981. Statistical comparison between line-pixel locations of uniformly distributed ground control points in the three geocoded products permitted quantitative measure of the offset over the sub-scene. Values of line and pixel misregistration obtained using the manual ground control points and digital correlation are tabulated and discussed.

Grieve, G.↗

NASA NTRS1984

Marshall Amateur Club experiment (MARCE)

The integration of the Get Away Special (GAS) payload for the space shuttle is discussed in terms of systems design. In addition to the primary power, control, and distribution networks to electrically integrate the spaceborne experiments, an instrument measuring system, a data system, and a radio frequency downlink system were designed. A brief review of these systems is given.

Stluka, E. F.↗

NASA NTRS1984

Shape of porous region to control cooling along curved exit boundary

A cooled porous insert in a curved wall has a specified spatially varying heat flux applied to one side. It is desired to control the distribution of coolant flow out through this curved surface so that the surface will be kept at a desired uniform temperature. The flow regulation is accomplished by shaping the surface through which the coolant enters the region to obtain the required variation of flow resistance within the region. The proper surface shape is found by solving a Cauchy boundary value problem. Analytical solutions are given in two dimensions for various shapes of the heated boundary subjected to different heating distributions.

Siegel, R.↗

NASA NTRS1984

Small Payload Flight Systems (SPFS)

The Small Payload Flight System (SPFS) provides a simple and cost-effective approach to carrying small size experiments on the space shuttle. The system uses a bridge-like structure which spans the orbiter cargo bay but is only 3 feet in length. The structure can carry up to 4300 lb of payload weight and can be positioned at any location along the length of the cargo bay. In addition to the structural support, the SPFS provides avionics services to experiments. These include electrical power distribution and control, command and telemetry for control of the experiments and subsystem health monitoring, and software computations. The avionics system includes a flight qualified electrical power branching distributor, and a system control unit based on the Intel 8086 microprocessor. Data can be recorded on magnetic tape or transmitted to the ground. Finally, a Freon pump and cold plate system provides environmental control for both the avionics hardware and the experiments as necessary.

Mitchell, R. A. K.↗

NASA NTRS1985

Human factors in space station architecture 1: Space station program implications for human factors research

The space station program is based on a set of premises on mission requirements and the operational capabilities of the space shuttle. These premises will influence the human behavioral factors and conditions on board the space station. These include: launch in the STS Orbiter payload bay, orbital characteristics, power supply, microgravity environment, autonomy from the ground, crew make-up and organization, distributed command control, safety, and logistics resupply. The most immediate design impacts of these premises will be upon the architectural organization and internal environment of the space station.

Cohen, M. M.↗

NASA NTRS1983

Computer graphics applications to crew displays

Astronauts are provided much data and information via the monochrome CRT displays on the orbiter. For this project two areas were investigated for the possible introduction of computer graphics to enhance and extend the utility of these displays. One involved reviewing the current orbiter displays and identifying those which could be improved via computer graphics. As an example, the tabular data on electrical power distribution and control was enhanced by the addition of color and bar charts. The other dealt with the development of an aid to berthing a payload with the Remote Manipulator System (RMS). This aid consists of a graphics display of the top, front and side views of the payload and cargo bay and point of resolution (POR) position and attitude data for the current location of the payload. The initial implementation was on an IBM PC clone. The demonstration software installed in the Johnson Space Center Manipulator Development Facility (MD) was reviewed. Due to current hardware limitations, the MDF verision is slow, i.e., about a 40+ seond update rate and, hence, not real-time. Despite this fact, the evaluation of this additional visual cue as an RMS operator aid indicates that this display, with modifications for speed, etc., can assist the crew. Further development is appropriate.

Wyzkoski, J.↗

NASA NTRS1986

Development of an Emulation-simulation Thermal Control Model for Space Station Application

Analysis techniques to evaluate the effects of changing thermal loads and the methods utilized to control temperature distributions in the orbital space station are essential. Analysis techniques including a user-friendly computer program, were developed which should prove useful in thermal design and system analysis of the the space station. The program uses a data base and user input to compute costs, sizes, and power requirements for individual components and complete systems. User input consists of selecting mission parameters, selecting thermal acquisition configurations, transport systems and distances, and thermal rejection configurations.

Colwell, G. T.↗

NASA NTRS1985

Experience with a software engineering environment framework

Experience with a software engineering environment framework tool called the Automated Product Control Environment (APCE) is described. The goals of the framework design, an overview of the major functions and features of the framework, and implementation and use of the framework are presented. Aspects of the framework discussed include automation and control; portability, distributability, and interoperability; cost/benefit analysis; and productivity. Results of using the framework are discussed and the framework approach is briefly compared to other software development environment approaches.

Blumberg, R.↗

NASA NTRS1985

Random and block copolymerization in metal oxide gel synthesis from metalorganic compounds

The introduction and development of the block copolymerization concept in metal oxide gel synthesis will in the future generate a new class of glass/microcrystalline materials. By the year 2004, better scientific understanding of the chemical principles controlling the distribution of network formers or modifiers in silicate gels will permit the synthesis of architecturally well-defined block polymers with unique high-performance behavior.

Mukherjee, S. P.↗

NASA NTRS1986

A numerical algorithm for optimal feedback gains in high dimensional LQR problems

A hybrid method for computing the feedback gains in linear quadratic regulator problems is proposed. The method, which combines the use of a Chandrasekhar type system with an iteration of the Newton-Kleinman form with variable acceleration parameter Smith schemes, is formulated so as to efficiently compute directly the feedback gains rather than solutions of an associated Riccati equation. The hybrid method is particularly appropriate when used with large dimensional systems such as those arising in approximating infinite dimensional (distributed parameter) control systems (e.g., those governed by delay-differential and partial differential equations). Computational advantage of the proposed algorithm over the standard eigenvector (Potter, Laub-Schur) based techniques are discussed and numerical evidence of the efficacy of our ideas presented.

Banks, H. T.↗

NASA NTRS1987

Approximation of discrete-time LQG compensators for distributed systems with boundary input and unbounded measurement

The approximation of optimal discrete-time linear quadratic Gaussian (LQG) compensators for distributed parameter control systems with boundary input and unbounded measurement is considered. The approach applies to a wide range of problems that can be formulated in a state space on which both the discrete-time input and output operators are continuous. Approximating compensators are obtained via application of the LQG theory and associated approximation results for infinite dimensional discrete-time control systems with bounded input and output. Numerical results for spline and modal based approximation schemes used to compute optimal compensators for a one dimensional heat equation with either Neumann or Dirichlet boundary control and pointwise measurement of temperature are presented and discussed.

Gibson, J. S.↗

NASA NTRS1986

Development of an emulation-simulation thermal control model for space station application

The orbiting space station being developed by NASA will have many thermal sources and sinks as well as requirements for the transport of thermal energy through large distances. The station is also expected to evolve over twenty or more years from an initial design. As the station evolves, thermal management will become more difficult. Thus, analysis techniques to evaluate the effects of changing various thermal loads and the methods utilized to control temperature distributions in the station are essential. Analysis techniques, including a user-friendly computer program, were developed which should prove useful to thermal designers and system analysts working on the space station. The program uses a data base and user input to compute costs, sizes, and power requirements for individual components and complete systems. User input consists of selecting mission parameters, selecting thermal acquisition configurations, transport systems and distances, and thermal rejection configurations. The capabilities of the program may be expanded by including additional thermal models as subroutines.

Hartley, James G.↗

NASA NTRS1987

Traction-drive telerobot for space manipulation

The National Aeronautics and Space Administration (NASA) Space Station Program marks the begining of a new era in space utilization and habitation. Extensive use of remote manipulation and robotics to reduce astronaut extra-vehicular activity is expected. Emphasis on teleoperator technology in early Space Station phases, followed by growth of autonomous robotics capabilities, is planned. A new telerobot concept has been developed at Oak Ridge National Laboratory (ORNL) under NASA Langley Research Center sponsorship, to address the technical needs of both teleoperations and telerobotics for these future NASA programs. The concept is based on traction drives, redundant kinematics, modular construction, and a state-of-the-art distributed, hierarchical control system.

Herndon, J. N.↗

NASA NTRS1988

Approximation of discrete-time LQG compensators for distributed systems with boundary input and unbounded measurement

The approximation of optimal discrete-time linear quadratic Gaussian (LQG) compensators for distributed parameter control systems with boundary input and unbounded measurement is considered. The approach applies to a wide range of problems that can be formulated in a state space on which both the discrete-time input and output operators are continuous. Approximating compensators are obtained via application of the LQG theory and associated approximation results for infinite dimensional discrete-time control systems with bounded input and output. Numerical results for spline and modal based approximation schemes used to compute optimal compensators for a one-dimensional heat equation with either Neumann or Dirichlet boundary control and pointwise measurement of temperature are presented and discussed.

Gibson, J. S.↗

NASA NTRS1989

Development status of the SP-100 power system

The SP-100 Program, whose goal is to develop 10 to 1000 kW electric space reactor power systems for use in civil and military space missions in the mid 1990s and beyond, is described. The major accomplishments of the SP-100 ground engineering system development project are: (1) completion of the preliminary design of the reactor test facility, and (2) completion of the generic flight system design which meets the technical specifications and is the basis for all the ground engineering system analytical and experimental tasks. The power conditioning, control, and distribution subsystem is indicated schematically.

Mondt, Jack F.↗

NASA NTRS1989

Distributed parameter actuators for structural control

Timoshenko beam theory is applied to beams with multiple layers of piezoelectric material attached. The model is developed using a Hamiltonian approach, and includes the external electrical circuit as well as a complete set of boundary conditions. Resistors are added to the sensor layers for passive damping. The resulting model is then formulated in state space.

Cudney, H. H.↗