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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 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS1976

Electronic system for optical shutter control

The paper describes a precise and versatile electronic system for shutter control in light beam experiments. Digital and analog circuitry is used to provide automatic timing, exposure control, manual operation, and remote programmability. A block diagram of the system is presented and the individual circuits - the timer control circuit, the clock control circuit, the comparator circuit, the exposure (integrator) circuit, and the shutter drive circuit are discussed in detail and diagrams are provided.

Viljoen, H. C.↗

NASA NTRS1975

On-orbit flight control algorithm description

Algorithms are presented for rotational and translational control of the space shuttle orbiter in the orbital mission phases, which are external tank separation, orbit insertion, on-orbit and de-orbit. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effectors by using an executive routine/functional subroutine format. Software functional requirements are described using block diagrams where feasible, and input--output tables, and the software implementation of each function is presented in equations and structured flow charts. Included are a glossary of all symbols used to define the requirements, and an appendix of supportive material.

Source record↗

NASA NTRS1977

Implementation of a maximum likelihood convolutional decoder in the DSN

The development status of the decoder and the factors which were considered in defining the specific functional requirements are described. The design is discussed to the block diagram level. A description of the detailed design is provided, along with a description of the test software developed and a brief summary of the performance evaluation testing completed so far.

Alberda, M. E.↗

NASA NTRS1976

High Resolution Ozone Mapper (HROM)

Using the backscatter ultraviolet instrument (BUV) aboard NIMBUS 4 as a baseline, point scanner mechanisms and spatial multiplex scanning systems were compared on the basis of sensitivity, field of view and simplicity. This comparison included both spectral and spatial scanning and multiplexing techniques. The selected system which optimally met the performance requirements for a shuttle based instrument was a pushbroom spatial scanner using a 15 element photomultiplier tube array and a Hadamard multiplex spectral scan. The selected system was conceptually designed. This design includes ray traces of the monochromator, mechanical layouts and the electronic block diagram.

Kohr, J. R.↗

NASA NTRS1975

Seminar on Understanding Digital Control and Analysis in Vibration Test Systems

The advantages of the digital methods over the analog vibration methods are demonstrated. The following topics are covered: (1) methods of computer-controlled random vibration and reverberation acoustic testing, (2) methods of computer-controlled sinewave vibration testing, and (3) methods of computer-controlled shock testing. General algorithms are described in the form of block diagrams and flow diagrams.

Source record↗

NASA NTRS1977

Pioneer Venus wind experiment receiver

The final design of the Pioneer Venus Wind Experiment Receiver and Phase Calibrator is discussed from the block diagram viewpoint. Measured phase data are shown to derive the predicted performance. The STDN receiver implementation is also discussed.

Nishimura, H.↗

NASA NTRS1977

Development and performance of power processor system for 2-gigahertz, 200-watt amplifier for communications technology satellite

The electrical and environmental requirements for a power processor system (PPS) designed to supply the appropriate voltages and currents to a 200-watt traveling wave tube (TWT) for a communication technology satellite is described. A block diagram of the PPS, the interface requirements between the PPS and spacecraft, the interface requirements between the PPS and 200-watt TWT, and the environmental requirements of the PPS are presented. Also included are discussions of protection circuits, interlocking sequences, and transient requirements. Predictions of the flight performance, based on ground test data, are provided.

Siegert, C. E.↗

NASA NTRS1977

Heat capacity mapping radiometer for AEM spacecraft

The operation, maintenance, and integration of the applications explorer mission heat capacity mapping radiometer is illustrated in block diagrams and detail schematics of circuit functions. Data format and logic timing diagrams are included along with radiometric and electronic calibration data. Mechanical and electrical configuration is presented to provide interface details for integration of the HCMR instrument to AEM spacecraft.

Sonnek, G. E.↗

NASA NTRS1975

Application of a postulate based control theory for an artificial arm

The biocontroller, remnant of the natural arm, and feedback elements must be considered in designing a controller for an above elbow artificial arm for amputees. This fundamental postulate is used to derive equations for developing the controller, which is shown in block diagrams.

Jacobsen, S. C.↗

NASA NTRS1977

Study to investigate and evaluate means of optimizing the Ku-band combined radar/communication functions for the space shuttle

The performance of the space shuttle orbiter's Ku-Band integrated radar and communications equipment is analyzed for the radar mode of operation. The block diagram of the rendezvous radar subsystem is described. Power budgets for passive target detection are calculated, based on the estimated values of system losses. Requirements for processing of radar signals in the search and track modes are examined. Time multiplexed, single-channel, angle tracking of passive scintillating targets is analyzed. Radar performance in the presence of main lobe ground clutter is considered and candidate techniques for clutter suppression are discussed. Principal system parameter drivers are examined for the case of stationkeeping at ranges comparable to target dimension. Candidate ranging waveforms for short range operation are analyzed and compared. The logarithmic error discriminant utilized for range, range rate and angle tracking is formulated and applied to the quantitative analysis of radar subsystem tracking loops.

Weber, C. L.↗

NASA NTRS1977

Development of a standardized control module for dc-to-dc converters

The electrical performance of a power processor depends on the quality of its control system. Most of the existing control circuits suffer one or more of the following imperfections that tend to restrict their respective utility: (1) inability to perform different modes of duty cycle control; (2) lack of immunity to output filter parameter changes, and (3) lack of capability to provide power component stress limiting on an instantaneous basis. The three lagging aspects of existing control circuits have been used to define the major objectives of the current Standardized Control Module (SCM) Program. Detailed information on the SCM functional block diagram, its universality, and performance features, circuit description, test results, and modeling and analysis efforts are presented.

Yu, Y.↗

NASA NTRS1976

An algorithm for automatic reduction of complex signal flow graphs

A computer algorithm is developed that provides efficient means to compute transmittances directly from a signal flow graph or a block diagram. Signal flow graphs are cast as directed graphs described by adjacency matrices. Nonsearch computation, designed for compilers without symbolic capability, is used to identify all arcs that are members of simple cycles for use with Mason's gain formula. The routine does not require the visual acumen of an interpreter to reduce the topology of the graph, and it is particularly useful for analyzing control systems described for computer analyses by means of interactive graphics.

Young, K. R.↗

NASA NTRS1976

Simulation analysis of a microcomputer-based, low-cost omega navigation system

A status report is presented on a proposed low-cost Omega Navigation System (ONS) based on a microcomputer (Available commercially). Minimum hardware and maximum software are designed for. Electronic subsystems are discussed in detail, with block diagrams of the receiver and microcomputer interface modules, and a flowchart of the automatic synchronization process. The system is designed as a precision navaid for general aviation in the $1000 price range.

Lilley, R. W.↗

NASA NTRS1977

Utilization of separate surface control systems on general aviation aircraft

The application of separate surface control systems to general aviation aircraft is discussed. Block diagrams of a conventional control system with autopilot tie-in and of a separate surface control system are presented, and the advantages and disadvantages of the two systems are compared. Theoretical descriptions of pilot-in-the-loop operation and operation in the autopilot mode are presented. The application of separate surface stability augmentation in yaw dampers, wing levelers, and static longitudinal stability augmentation is examined. The state-of-the-art of separate control surface technology is summarized.

Roskam, J.↗

NASA NTRS1978

Graphical evaluation of relativistic matrix elements

A graphical representation of angular momentum was used to evaluate relativistic matrix elements between antisymmetrized states of many particle configurations having any number of open shells. The antisymmetrized matrix element was expanded as a sum of semisymmetrized matrix elements. The diagram representing a semisymmetrized matrix element was composed of four diagram blocks; the bra block, the ket block, the spectator block, and the interaction block. The first three blocks indicate the couplings of the two interacting configurations while the last depends on the interaction and is the replaceable component. Interaction blocks for relativistic operators and commonly used potentials were summarized in ready to use forms. A simple step by step procedure was prescribed generally for calculating antisymmetrized matrix elements of one and two particle operators.

Huang, K. N.↗

NASA NTRS1977

Interactive image processing for meteorological applications at NASA/Goddard Space Flight Center

The paper reviews the development of the AOIPS (Atmospheric and Oceanographic Information Processing System) system for the interactive manipulation of meteorological satellite images. A block diagram of the system is presented; both software and hardware considerations are examined; and attention is given to the Image 100 processing system and to the interactive terminal. As a example the paper examines the functions of Metpak (the software package) which involve cloud tracking and wind vector generation.

Billingsley, J. B.↗

NASA NTRS1978

Earth viewing with a shuttleborne experiment pointing mount

The article considers the attitude determination and the control problems of the shuttleborne earth-viewing pointing mounts (EPMs). Per-axis pointing performance requirements are identified for troposphere/stratosphere pollution, tropical storm research, and urban air pollution. Ephemeris error contributions to earth pointing are discussed and candidate attitude reference systems are described. Primary interfaces between the orbiter flight control system, Spacelab, pallet-mounted EPM, and control subsystems are outlined. A block diagram is given of the EPM-mounted stellar-inertial attitude reference system. The system's performance is evaluated on the basis of the inertial sensor and a three-axis covariance analysis.

Iwens, R. P.↗

NASA NTRS1978

The ISEE-C vector helium magnetometer

The ISEE-C magnetometer will make continuous observations of the interplanetary magnetic field near 1 AU. This paper describes the scientific objectives of the magnetometer experiment and gives attention to instrument design (sensor, electronics, and operating principles). A functional block diagram of the system is presented and attention is given to minor modifications required by the ISEE mission (the magnetometer is essentially one that served as the spare unit for the Pioneer 10 and 11 missions to Jupiter).

Frandsen, A. M. A.↗