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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Comparison of seven performance measures in a time-delayed manipulation task

Real-time performance data was collected during a pick-up task carried out with a Rancho master-slave manipulator using a minicomputer-based data taker. In addition to the usual task-time measurements, computer algorithms to integrate the energy consumed and to count and time the number of moves were implemented. In addition to these measures, several derived measures such as the fraction of time moving (MRATIO) and mean time per move (MBAR) were obtained in an off-line analysis. Preliminary results of the time delay experiment indicate that two new measures, MRATIO and MBAR, are almost an order of magnitude more sensitive than task time, the conventional measure, in determining performance changes with transmission delays in the range from 0.0 to 1.0s.

Hill, J. W.↗
NASA NTRS1975

Onboard navigation of the Space Shuttle

This paper discusses the Kalman filter used in the navigation software of the Space Shuttle. The form of the filter will be discussed: the standard Kalman filter versus the square-root version of this filter. Both of these filters have severe nonlinearity problems. Two successful solutions of the nonlinearity problem are presented. A real-time program must have a good method of editing bad data. The data editing scheme is discussed. Those elements of the Kalman filter state vector which are random variables will be discussed.

Lear, W. M.↗
NASA NTRS1976

Optical computing with laser light

Linear and nonlinear optical processing techniques (Fourier transformation, convolution and correlation, arithmetic operations - addition and subtraction with gratings, generalized orthogonal transformations; theta modulation, half-tone screen process, optical feedback) for mathematical computations are reviewed. The use of gratings and computer holograms in addition, subtraction, differentiation, and application of generalized transformations is discussed. Use of nonlinear optical elements with or without optical coherent feedback in such nonlinear operations as taking logarithms and thresholding is described. Applications in hybrid systems incorporating digital computer and optical processor with real-time interface devices, or optical threshold and logic devices for parallel processing to apply digital techniques to optical information are considered.

Lee, S. H.↗
NASA NTRS1975

A biological and physical oceanographic remote sensing study aboard the Calypso

The paper discusses an oceanographic remote sensing program conducted aboard the R/V Calypso in the Gulf of Mexico and the Caribbean Sea to provide information for correlating ocean measurements with remotely sensed observations. Remote sensors on satellites and aircraft are used as operations and experiment planning tools as well as for scientific data acquisition. Emphasis is on providing surface-truth measurements for OCS flights and on investigating the area of the Gulf affected by the outflow of the Mississippi River. The discussion covers the shipboard instrumentation, ocean color scanner data acquisition and results, NOAA/VHRR data analysis approach, and Landsat and APT/ATS as planning tools. The research effort has demonstrated the feasibility of using satellite data as a supportive method to aid an oceanographic research vessel on a near real-time basis.

Harlan, J. C.↗
NASA NTRS1976

New horizons for study of the cardiopulmonary and circulatory systems

The paper discusses the development of computer-controlled three-dimensional reconstruction techniques designed to determine the dynamic changes in the true shape and dimensions of the epi- and endocardial surfaces of the heart, along with variable time base (stop-action to real-time) displays of the transmural distribution of the coronary microcirculation and the three-dimensional anatomy of the macrovasculature in all regions of the body throughout individual cardiac and/or respiratory cycles. A technique for reconstructing a cross section of the heart from multiplanar videoroentgenograms is outlined. The capability of high spatial and high temporal resolution scanning videodensitometry makes possible measurement of the appearance, mean transit and clearance of roentgen opaque substances in three-dimensional space through the myocardium with a degree of simultaneous anatomic and temporal resolution not obtainable by current isotope techniques. The distribution of a variety of selected chemical elements or biologic materials within a body portion can also be determined.

Wood, E. H.↗
NASA NTRS1976

Location of ATS-5 by L-band trilateration

Near real-time ATS-5 satellite positions and short term position predictions were derived from an experimental L-band trilateration network. Satellite position accuracies of approximately 0.0002 degrees in latitude and longitude and 20 meters in earth center distance were demonstrated. Individual slant range measurements from the master ground station to the satellite were precise to within 12 meters; from the satellite to each of two automatic remote transponders, 23 meters. The trilateration network comprised a master ground station near Schenectady, New York and remote unmanned transponders in Buenos Aires, Argentina and near Wahiawa, Hawaii.

Brisken, A. F.↗
NASA NTRS1976

Program definition and preliminary results of a long-term evaluation program of advanced composites for supersonic cruise aircraft applications

Advanced composites will play a key role in the development of the technology required for the design and fabrication of future supersonic vehicles. A program is in progress to determine the time-temperature-stress capabilities of several high-temperature composite materials. Tests included in this study are thermal aging, ambient aging, fatigue, creep, fracture, tensile, and real-time flight-simulation exposure. The program has two parts. The first includes all the material-property determinations and aging and simulation exposures up through 10,000 h. The second continues these tests up to 50,000 cumulative h. The program is currently in the midst of the 10,000-h phase. Some of the results obtained to date and the status of the various tests are discussed.

Kerr, J. R.↗
NASA NTRS1976

Research in ground-based near-terminal area 4D guidance and control

This paper describes work being done at NASA, Langley Research Center and at the Research Triangle Institute on advanced, ground-based guidance and control for the near terminal area. Large-scale computer traffic simulations in conjunction with flight experiments with a Boeing 737 aircraft will be used to evaluate various concepts for automated terminal area metering and spacing. The all-digital real-time air traffic simulation model is described. Facilities for aircraft tracking and for interfacing the aircraft with the digital simulation are discussed, along with possible application to other types of experiments.

Britt, C. L., Jr.↗
NASA NTRS1976

Effects of rotor model degradation on the accuracy of rotorcraft real time simulation

The effects are studied of degrading a rotating blade element rotor mathematical model to meet various real-time simulation requirements of rotorcraft. Three methods of degradation were studied: reduction of number of blades, reduction of number of blade segments, and increasing the integration interval, which has the corresponding effect of increasing blade azimuthal advance angle. The three degradation methods were studied through static trim comparisons, total rotor force and moment comparisons, single blade force and moment comparisons over one complete revolution, and total vehicle dynamic response comparisons. Recommendations are made concerning model degradation which should serve as a guide for future users of this mathematical model, and in general, they are in order of minimum impact on model validity: (1) reduction of number of blade segments, (2) reduction of number of blades, and (3) increase of integration interval and azimuthal advance angle. Extreme limits are specified beyond which the rotating blade element rotor mathematical model should not be used.

Houck, J. A.↗
NASA NTRS1975

Three-dimensional reconstruction and display of the heart, lungs and circulation by multiplanar X-ray scanning videodensitometry

A device was developed which makes possible the dynamic reconstruction of the heart and lungs within the intact thorax of a living dog or human and which can record approximately 30 multiplanar X-ray images of the thorax practically instantaneously, and at frequent enough intervals of time and with sufficient density and spatial resolution to capture and resolve the most rapid changes in cardiac structural detail throughout each cardiac cycle. It can be installed in a clinical diagnostic setting as well as in a research environment and its construction and application for determination and display in real-time modes of cross sections of the functioning thorax and its contents of living animals and man is technologically feasible.

Robb, R. A.↗
NASA NTRS0992

Current status: Animal models of nausea

The advantages, and possible benefits of a valid, reliable animal model for nausea are discussed, and difficulties inherent to the development of a model are considered. A principle problem for developing models arises because nausea is a subjective sensation that can be identified only in humans. Several putative measures of nausea in animals are considered, with more detailed consideration directed to variation in cardiac rate, levels of vasopressin, and conditioned taste aversion. Demonstration that putative measures are associated with reported nausea in humans is proposed as a requirement for validating measures to be used in animal models. The necessity for a 'real-time' measure of nausea is proposed as an important factor for future research; and the need for improved understanding of the neuroanatomy underlying the emetic syndrome is discussed.

Robert A Fox↗
NASA NTRS1961

Project Echo: Antenna Steering System

The Project Echo communications experiment employed large, steerable,transmitting and receiving antennas at the ground terminals. It was necessary that these highly directional antennas be continuously and accurately pointed at the passing satellite. This paper describes a new type of special purpose data converter for directing narrow-beam communication antennas on the basis of predicted information. The system is capable of converting digital input data into real-time analog voltage commands with a dynamic accuracy of +/- 0.05 degree, which meets the requirements of the present antennas.

Klahn, R.↗
NASA NTRS1971

Detecting Oil on Water: A Comparison of Known Techniques

This paper reviews new developments in oil pollution detection and compares available techniques according to their effectiveness. Emphasis is on in situ and remote sensing techniques, with a potential for real-time, automated operation. No mention is made of traditional methods, requiring that a sample be taken to a laboratory for tests of solubility, chemical reactions, or other properties.

Klemas, Vytautas↗
NASA NTRS1968

The Use of Large Lithium-Drifted, Germanium Diodes for Gamma-Ray Spectral Measurements at Balloon Altitudes

A series of balloon-borne experiments has been initiated at the Oak Ridge National Laboratory (ORNL) in cooperation with the Space Sciences Laboratory of the NASA G. C. Marshall Space Flight Center to determine the feasibility of using large (greater than 20 cc) lithium-drifted, germanium diodes to investigate the spectrum of atmospheric gamma rays (60 keV < E < 1.5 MeV) at altitudes corresponding to a few grams per cm (sup 2) residual atmosphere. The results of these measurements will also provide a basis for designing an appropriate shield for a multi-diode, highly directional gamma-ray spectrometer for use in astrophysical measurements. Two flights were accomplished during 1967 using the same two diodes and basic instrument package. Both flights were launched at the NCAR Scientific Balloon Flight Base, Palestine, Texas, and attained a float altitude of 117, 000 ft. The measured atmospheric gamma-ray spectrum shows at least one distinct line at 511 keV (annihilation radiation) superimposed on a continuous distribution of gamma rays attributable to both energy-degraded gamma rays and brems-strahlung photons. A second diode, encased in a passive shield of plastic and lead, shows the expected lines resulting from both neutron inelastic scattering and capture in the germanium. Data acquisition was accomplished on an event-by-event basis through the use of 512-channel, on-board ADC and word-generator circuits and a ground-based, on-line telemetry decoder. The decoder makes it possible to store the data in the memory of a modified pulse-height analyzer simultaneously with storage on magnetic tape. This provides a real-time visual observation of the data as it is accumulated and greatly facilitates preflight calibrations.

Chapman, G. T.↗
NASA NTRS1966

Manned Space-Flight Experiments: Gemini V Mission (Interim Report)

This compilation of papers constitutes an interim report on the results of experiments conducted during the Gemini V manned space flight. The results of experiments conducted on Gemini III and IV manned space flights have been published previously in a similar interim report, "Manned Space Flight Experiments Symposium, Gemini Missions III and IV," which is available upon request from MSC Experiments Program Office, Houston, Texas (Code EX, Attention of R. Kinard). The Gemini V mission provided the greatest opportunity to date for conducting experiments; the increased mission duration of eight days provided this added capability. The total mission experiment complement was seventeen. Five experiments were designed to obtain basic scientific knowledge, five were medical, and seven were technological and engineering in nature. Six of the experiments had flown previously on Gemini IV, and eleven were new. The results of the experiments, including real-time modification to preflight plans made necessary by abnormal spacecraft system operation, are presented.

Source record↗
NASA NTRS1972

A Holographic Interferometer System for Measuring Density Profiles in High-Velocity Flows

This paper describes a holographic interferometric technique for obtaining density measurements across a test gas that is traveling at a velocity of over 5500 meters per second in an expansion tube facility. Interferometric data describing the flow in the test section are obtained using a long coherence length cw argon laser in a holographic system and a rotating drum camera recorder. The object beam, which passes through the test section, intersects the reference beam at a small angle (5 degrees) to form an interference pattern of about 170 lines per millimeter, and is recorded as a hologram. Before a test, this hologram is placed in its original position and rotated slightly so that an interference pattern is generated by the intersection of the reconstructed and real-time object beams. This interference pattern is adjusted to a series of bright, horizontal fringes having a spatial frequency of about 5 fringes per centimeter. During the few milliseconds it takes the test gas to pass through the test section, variations in the gas density across the 8.4-centimeter test section produce phase variations in the object beam and result in a varying interference pattern. A rotating drum camera with a 0.15-millimeter slit aligned perpendicular to the fringes is used to record the varying fringe shifts with a time resolution of about 3 microseconds. The average gas density across the test section is determined by measuring these fringe shifts.

Burner, Alpheus W.↗
NASA NTRS2009

General Purpose Data-Driven System Monitoring for Space Operations

Modern space propulsion and exploration system designs are becoming increasingly sophisticated and complex. Determining the health state of these systems using traditional methods is becoming more difficult as the number of sensors and component interactions grows. Data-driven monitoring techniques have been developed to address these issues by analyzing system operations data to automatically characterize normal system behavior. The Inductive Monitoring System (IMS) is a data-driven system health monitoring software tool that has been successfully applied to several aerospace applications. IMS uses a data mining technique called clustering to analyze archived system data and characterize normal interactions between parameters. This characterization, or model, of nominal operation is stored in a knowledge base that can be used for real-time system monitoring or for analysis of archived events. Ongoing and developing IMS space operations applications include International Space Station flight control, satellite vehicle system health management, launch vehicle ground operations, and fleet supportability. As a common thread of discussion this paper will employ the evolution of the IMS data-driven technique as related to several Integrated Systems Health Management (ISHM) elements. Thematically, the projects listed will be used as case studies. The maturation of IMS via projects where it has been deployed, or is currently being integrated to aid in fault detection will be described. The paper will also explain how IMS can be used to complement a suite of other ISHM tools, providing initial fault detection support for diagnosis and recovery.

Satellites↗
NASA NTRS1961

A Long-Range Precision Ranging System

A technique is presented that may be used for precision real-time continuous range measuring at long ranges. The technique uses a carrier that is phase modulated by a pseudo-random binary sequence. The characteristics of the sequence that make it acquirable are discussed. The general form of a receiver capable of tracking the carrier is given and is shown to be a kind of phase-locked loop. A two-loop system capable of tracking a pseudo-random sequence and its clock is given. The combination of the receiver and the sequence tracking system form a ranging receiver. The power division necessary between the carrier and the sidebands is shown to be determined by the noise bandwidths of the two tracking systems. The bandwidths necessary for tracking space probes and Earth satellites are given and some experiments in radar-tracking Earth satellites are described. Based on these experiments, estimates are made of the useful range of such a system in tracking space probes.

Easterling, Mahlon↗