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At least 631 records · Page 35

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NASA NTRS1983

A large aperture balloon-borne telescope for a submillimeter wavelength survey of the galactic plane

A balloon-borne, 1.2 meter Cassegrain telescope with a servo-controlled chopping secondary mirror has been developed and used to survey the Galactic Plane at submillimeter wavelengths. The telescope pointing system uses a gyroscope as the primary stabilization reference and makes use of microprocessors for pointing control, on-board data collection, and telemetry formatting. A description of the telescope, multi-channel liquid-helium-cooled focal plane and the aspect and orientation subsystems are presented.

Silverberg, R. F.↗

NASA NTRS1983

Development of the functional simulator for the Galileo attitude and articulation control system

A simulation program for verifying and checking the performance of the Galileo Spacecraft's Attitude and Articulation Control Subsystem's (AACS) flight software is discussed. The program, which is called Functional Simulator (FUNSIM), provides a simple method of interfacing user-supplied mathematical models coded in FORTRAN which describes spacecraft dynamics, sensors, and actuators; this is done with the AACS flight software, coded in HAL/S (High-level Advanced Language/Shuttle). It is thus able to simulate the AACS flight software accurately to the HAL/S statement level in the environment of a mainframe computer system. FUNSIM also has a command and data subsystem (CDS) simulator. It is noted that the input/output data and timing are simulated with the same precision as the flight microprocessor. FUNSIM uses a variable stepsize numerical integration algorithm complete with individual error bound control on the state variable to solve the equations of motion. The program has been designed to provide both line printer and matrix dot plotting of the variables requested in the run section and to provide error diagnostics.

Namiri, M. K.↗

NASA NTRS1982

Advances in cryogenic engineering. Volume 27 - Proceedings of the Cryogenic Engineering Conference, San Diego, CA, August 11-14, 1981

Applications of superconductivity are considered, taking into account MHD and fusion, generators, transformers, transmission lines, magnets for physics, cryogenic techniques, electrtronics, and aspects of magnet stability. Advances related to heat transfer in He I are discussed along with subjects related to theat transfer in He II, refrigeration of superconducting systems, refrigeration and liquefaction, dilution and magnetic refrigerators, refrigerators for space applications, mass transfer and flow phenomena, and the properties of fluids. Developments related to cryogenic applications are also explored, giving attention to bulk storage and transfer of cryogenic fluids, liquefied natural gas operations, space science and technology, and cryopumping. Topics related to cryogenic instrumentation and controls include the production and use of high grade silicon diode temperature sensors, the choice of strain gages for use in a large superconducting alternator, microprocessor control of cryogenic pressure, and instrumentation, data acquisition and reduction for a large spaceborne helium dewar.

Fast, R. W.↗

NASA NTRS1983

Balloon-borne diode-laser absorption spectrometer for measurements of stratospheric trace species

An instrument has been designed for the measurement of stratospheric trace species which utilizes tunable infrared diode lasers as sources for sensitive in situ absorption spectroscopy in selected wavelength regions. This instrument, the Balloon-Borne Laser In Situ Sensor (BLISS), is a high-resolution absorption spectrometer designed to provide measurements of the concentrations of stratospheric species and their diurnal variations. The instrument employs second-harmonic detection of the absorption of tunable diode laser (TDL) radiation (3-30 microns) in a 1 km path length defined by a retroreflector lowered 0.5 km below the BLISS gondola. Retroreflector tracking under microprocessor control is obtained using a He-Ne laser and coaligned TV camera with CID imaging. Simultaneous measurements of molecular species in the 20-40 km altitude range will be performed using four TDLs, with the predicted minimum-detectable mixing ratio at 30 km being typically less than or equal to 0.1 ppbv.

Menzies, R. T.↗

NASA NTRS1983

The Mount Wilson magnetograph

In the summer of 1957, an instrument quite similar to the prototype solar magnetograph described by Babcock (1953) was installed at the 150-foot tower telescope at the Mount Wilson Observatory, and daily magnetograph observations of the full disk of the sun were started. During the following years, the instrument was modified and improved on several occasions. The present investigation is concerned with the present state of the magnetograph, which was largely rebuilt during 1981. Attention is given to the spectrograph entrance slit, the diffraction grating, the exit slit, the employed microprocessor, the setup procedure, the magnetic signal, the Doppler signal, and a solar magnetogram.

Howard, R.↗

NASA NTRS1983

Integrated flight/propulsion control system architectures for a high speed aircraft

The present investigation is concerned with the impact of integrated flight, inlet, and engine control system architectures on system effectiveness and life cycle cost (LCC). The aircraft employed in the investigation is a modified YF-12 with a cruise Mach number of 2.5. The aircraft has two advanced technology aircraft JT-69 afterburning, low-bypass turbofan engines. Advanced technologies suitable for use in future flight/propulsion control systems are related to distributed computer networks, fault tolerant computers and software, analytical redundancy, self-checking microprocessor pairs, advanced direct drive actuators, fiber optic data buses, VLSI microcircuits, and skewed sensors. The integrated architectures were found to have fewer sensors, actuators, and power sources than the nonintegrated architectures.

Bangert, L. H.↗

NASA NTRS1983

Integrated control system concept for high-speed aircraft

The synthesis and evaluation of flight control system architectures for future aircraft are discussed in terms of design features and the requirements for fighter aircraft. Advanced fighter configurations may feature canards, flaperons, two-dimensional vectoring nozzles, a mixing compression inlet, and an advanced turbojet engine. Survey and evaluation technology will also progress to include distributed microprocessors, VLSI and VHSIC microcircuitry, optical circuits, analytic redundancy, etc. Bottom-p and top-down architectures have been investigated to fulfill the reliability, maintainability, cost, and performance goals. A centralized architecture has been devised with line-removable units to facilitate maintainability and reduce weight. Descriptions are provided of the performance parameters and applications of optical elements, photoelastic pressure sensors, rare earth sensors, computing elements, and information transfer system.

Carlin, C. M.↗

NASA NTRS1985

Controlling Solar-Power Systems With Distributed Processors

System undergoing development uses distributed microprocessors to monitor and control photovoltaic power system. Equipment increases life expectancy and reliability of power system and decreases costs. Adapted to vehicular, residential, and commercial solar and nonsolar power systems. Equipment especially desirable in systems with overall power levels above few kilowatts.

Imamura, M. S.↗

NASA NTRS1985

Fiber-Optic Equipment for Power-System Control

Report surveys state of art in fiber optics and explores use of microprocessors communicating over optical fibers to control complicated power system with many producing and consuming units. Power system of study is of planetary spacecraft, and fiber-optic technology extension of that now under development or used in military aircraft and ships.

Bridgeforth, A. O.↗

NASA NTRS1985

Communication Program Emulates Switchboard

Software allows microprocessor systems to communicate with external devices. Flexible program completely menu-driven, and all local operator commands require only single keystroke.

Ron, D.↗

NASA NTRS1985

Laser Rangefinder and Remote Profilometer

Proposed laser rangefinder and profilometer operates with precision of about 1mm at ranges of up to 100m. With scanning optics, device could track objects or accurately measure shapes of objects in field of view. New microprocessor-controlled design uses variable-length fiber-optic delay line as distance reference. New rangefinding method used in vision systems for industrial robots.

Mclauchlan, J. M.↗

NASA NTRS1985

Integrated Exhaust-Gas-Analysis System

Gas-Analysis system includes eight commercial gas analyzers and data-processing and calibration electronics. Two microprocessors range analyzers, calibrate system, process raw data to units of concentration, and make all system information available to facility research computer and to operator. After initial setup, system operates several hours without significant operator attention. Saves considerable operator time.

Anderson, R.↗

NASA NTRS1983

Development and flight test of an X-band precision approach concept for remote-area rotorcraft operations

A novel airborne radar-based precision approach concept was developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. A demonstration, transponder-based beacon landing system (BLS), incorporating state-of-the-art X-band radar technology and digital processing techniques, was built and flight tested to demonstrate the concept feasibility. The BLS airborne hardware consists of an add-on microprocessor, installed in conjunction with the aircraft weather/mapping radar, which analyzes the radar beacon receiver returns and determines range, localizer deviation, and glide slope deviation. The ground station is an inexpensive, portable unit which can be quickly deployed at a landing site. Results from the flight test program show that the BLS concept has a significant potential for providing rotorcraft with low-cost, precision, instrument approach capability in remote areas.

Clary, G. R.↗

NASA NTRS1983

Flight evaluation results from the general-aviation advanced avionics system program

A demonstration advanced avionics system (DAAS) for general-aviation aircraft was tested at NASA Ames Research Center to provide information required for the design of reliable, low-cost, advanced avionics systems which would make general-aviation operations safer and more practicable. Guest pilots flew a DAAS-equipped NASA Cessna 402-B aircraft to evaluate the usefulness of data busing, distributed microprocessors, and shared electronic displays, and to provide data on the DAAS pilot/system interface for the design of future integrated avionics systems. Evaluation results indicate that the DAAS hardware and functional capability meet the program objective. Most pilots felt that the DAAS representative of the way avionics systems would evolve and felt the added capability would improve the safety and practicability of general-aviation operations. Flight-evaluation results compiled from questionnaires are presented, the results of the debriefings are summarized. General conclusions of the flight evaluation are included.

Callas, G. P.↗

NASA NTRS1983

The 400-Hz aircraft power-generation systems: Advancing the baseline

Today's benchmark system for the Boeing 757/767/A310 airplanes and future trends in hydromechanical aircraft power generating systems are discussed. The 757/767/A310 system represents the commercial state of the art and the direction in which Sundstrand Corp. is headed, particularly in regard to weight reduction. Sundstrand introduced microprocessor control in an in service system in the Boeing 767 and was the first to use databus communications between the controls. Plans to develop this technology are briefly discussed. Alternative ways to produce and use power in aircraft are discussed. The integrated starter drive is discussed.

Glennon, T.↗

NASA NTRS1983

NASA Demonstration Advanced Avionics System (DAAS)

The Demonstration Advanced Avionics Systems (DAAS) integrates a comprehensive set of general aviation avionics functions into an advanced system architecture for demonstration in a Cessna 402 aircraft. A cursory functional description of the DAAS complex is given. Microprocessors, computer architecture, and display devices are discussed.

Peterson, E. M.↗

NASA NTRS1983

Design, development and flight test of a demonstration advanced avionics system

The design of integrated avionics suitable for general aviation was examined. The program emphasizes the use of data busing, distributed microprocessors, shared electronic displays and data entry devices, and improved functional capability. Design considerations includes cost, reliability, maintainability, and modularity. A demonstration advanced avionics system (DAAS) was designed, built, and flight tested in a Cessna 402, twin engine, general aviation aircraft. The DAAS, and the system architecture are described.

Denery, D. G.↗

NASA NTRS1983

Recording and reproduction of microwave holograms using a scanning procedure and their subsequent optical processing

Intensity distributions in nonoptical wave fields can be visualized and stored on photosensitive material. In the case of microwaves, temperature effects can be utilized with the aid of liquid crystals to visualize intensity distributions. Particular advantages for the study of intensity distributions in microwave fields presents a scanning procedure in which a microcomputer is employed for the control of a probe and the storage of the measured data. The present investigation is concerned with the employment of such a scanning procedure for the recording and the reproduction of microwave holograms. The scanning procedure makes use of an approach discussed by Farhat, et al. (1973). An eight-bit microprocessor with 64 kBytes of RAM is employed together with a diskette storage system.

Hetsch, J.↗