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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Electrical-power-system data base for consumables analysis. Volume 1: Electrical equipment list, activity blocks, and time lines

A standardized data base is described which consists of a space shuttle electrical equipment list, activity blocks defining electrical equipment utilization, and activity-block time lines for specific mission analyses. Information is presented to facilitate utilization of the data base, to provide the basis for the electrical equipment utilization to enable interpretation of analyses based on the data contained herein.

Pipher, M. D.↗
NASA NTRS1975

Boost navigation and guidance

The verification that the boost mode portion of the flight program correctly provides navigation and guidance functions for the vehicle during periods when significant, measurable accelerations exist was described. Many test cases and performance cases are made, testing the ability of the navigation and guidance routines to properly compensate for several perturbations. Various plots of special interest parameters are made on all performance cases, facilitating a check on each calculation (each boost major loop) of these parameters.

Source record↗
NASA NTRS1974

Research and operational efforts in support of Skylab experiment M093

The objectives of Skylab Experiment M093 were to measure electrocardiographic signals during spaceflight, to elucidate the electrophysiological basis for the changes observed, and to assess the effect of the change on the human cardiovascular system. Vectorcardiographic methods were used to quantitate changes, standardize data collection, and to facilitate reduction and statistical analysis of data. In this report the authors describe the M093 experiment design, the data transmission system, data reduction methods, and the analysis of data from the three Skylab missions. The report also includes clinical applications of the techniques developed for Skylab Experiment M093.

Smith, R. F.↗
NASA NTRS1975

Improved semi-conductor laser device, operating, at room temperature, with an array of three lasers in the spatially coherent, free running mode

The peak pulse power was increased by operating an array of three homostructure Ga As lasers in the laser device. A spatial filter in the laser device selects the spatially coherent, free running, mode. The optical peak power is 5 watts, which is three times the peak power of a single laser in the array. The far-field distribution of the three laser array is a single Gaussian beam of spatial coherence without sidelobes or grating lobes. The length of the optical pulses of spatial coherence was increased to 200 ns by improved heat transfer from the p-n junctions of the lasers to the metal housing of the pulse transformer, and by doubling the core area and increasing the turns of the primary windings of the pulse transformer. The mechanical stability of the laser device was improved and the transition from mechanical alignment to electro-mechanical alignment control, was facilitated.

Rutz, E. M.↗
NASA NTRS1974

SNAP 19 Viking RTG flight configuration and integration testing

The Viking-75 mission environments and lander interface requirements which influence the design of the RTG (radioisotope thermoelectric generator), as well as RTG-related constraints are discussed. The baseline RTG design evolved from these considerations is presented with particular emphasis on the design features which make the Viking RTG unique. These features include a gas management system employing a separate gas reservoir to maintain the RTG hot junction and heat source temperatures within a desired range throughout the various mission phases, as well as a specially profiled housing/radiator assembly which facilitates both ground cooling of the RTGs prior to launch and thermal control of the lander after landing. Also presented is the expected RTG electrical performance when subjected to the various mission environments/requirements, such as 'power-up' operations in Mars orbit just prior to the entry, and thermal cycling on the Martian surface after landing.

Brittain, W. M.↗
NASA NTRS1974

The major Martian dust storms of 1971 and 1973

Comparison of the major features of the two largest Martian dust storms on photographic record, namely those of 1971 and 1973. Maps of the first nine days of both storms are presented to facilitate a comparison of their initial outbreaks and growth. The frequency and regularity of storms of this size are uncertain because of the lack of comprehensive photographic observation during past apparitions.

Martin, L. J.↗
NASA NTRS1974

Skylab Workshop experience in experiment accommodation

This paper examines the experiment support facilities available from the Orbital Workshop (OWS) module of the Skylab. Experiments and associated support provisions have been selected and described to illustrate the various accommodations and degree of complexities involved in the integration of these experiments into the Workshop. The interfaces described start with the simple and proceed to the complex. On the basis of the experience gained in integrating the experiments into the Workshop, conclusions are drawn and suggestions are made on ways to facilitate future experiment operations and at the same time simplify and reduce the cost of integration efforts.

Hanlon, W. H.↗
NASA NTRS1974

Skylab and ERTS-1 investigations of coastal land-use and water properties in Delaware Bay

Study of coastal land use and water properties of Delaware Bay using digital and visual analysis of enhanced imagery from NASA's Earth Resources Technology Satellite (ERTS) and from the Skylab Earth Resources Experimental Package (EREP). ERTS is shown to have the advantage of repetitive coverage of the test site which facilitates change detection experiments by gathering data under a variety of tidal, seasonal, and atmospheric conditions. Skylab-EREP data, on the other hand, are superior in both spatial and spectral resolution.

Klemas, V.↗
NASA NTRS1974

X-rays from an auroral substorm at altitudes of 60-80 km and 15-20 km

A technique for the measurement of high altitude X-rays associated with auroral events is described. The instrument package is boosted to the lower D region by a rocket and descends slowly by parachute. This arrangement facilitates coordination with the launching of other rocket probes during events of interest. A flight on Feb. 2, 1973 from the Churchill Research Range provided 17 minutes of X-ray data above 28 km. The flight was made into an intense break-up event and X-ray fluxes were observed during two episodes of the explosive phase. The reduction of auroral absorption during the later phases of the event suggests precipitation of energetic electrons unaccompanied by the lower energy precipitation responsible for the absorption earlier in the substorm.

Sheldon, W. R.↗
NASA NTRS1974

Coastal and estuarine studies with ERTS-1 and Skylab

Coastal vegetation, land use, current circulation, water turbidity, and ocean waste dispersion were studied by interpreting ERTS-1 and Skylab imagery with the help of ground truth collected during overpasses. Based on high-contrast targets such as piers and roads, the ERTS-1 multispectral scanner was found to have a resolution of 70-100 m, Skylab's S190A cameras about 20-40 m, and its S190B camera about 10-20 m. Important coastal land-use details can be more readily mapped using Skylab's imagery. On the other hand, the regular 18-day cycle of ERTS-1 allows observation of important man-made and natural changes, and facilitates collection of ground truth.

Klemas, V.↗
NASA NTRS1974

Implementation of an advanced table look-up classifier for large area land-use classification

Software employing Eppler's improved table look-up approach to pattern recognition has been developed, and results from this software are presented. The look-up table for each class is a computer representation of a hyperellipsoid in four dimensional space. During implementation of the software Eppler's look-up procedure was modified to include multiple ranges in order to accommodate hollow regions in the ellipsoids. In a typical ERTS classification run less than 6000 36-bit computer words were required to store tables for 24 classes. Classification results from the improved table look-up are identical with those produced by the conventional method, i.e., by calculation of the maximum likelihood decision rule at the moment of classification. With the new look-up approach an entire ERTS MSS frame can be classified into 24 classes in 1.3 hours, compared to 22.5 hours required by the conventional method. The new software is coded completely in FORTRAN to facilitate transfer to other digital computers.

Jones, C.↗
NASA NTRS1974

Spacelab communications experiments

The Space Shuttle launched Spacelab is planned to provide the communications community with a platform to develop the technology required for NASA's and DOD's missions, and future domestic and international communications satellites in the 1980s. The Laboratory, with a weight carrying capability of 14,500 kg into a low-earth orbit and return to earth, is being planned to carry laser telescopes; large (greater-than 10 meter) deployable antennas; spaceborne receivers to map terrestrial noise sources in a variety of frequency bands, and other advanced technology applicable to the 1980s and 1990s. Spacelab will also facilitate ease of comparative testing between alternative or competing experiments, subsystems and components prior to a commitment to an automated satellite.

Ehrlich, E.↗
NASA NTRS1975

Magnetospheric mapping with a quantitative geomagnetic field model

Mapping the magnetosphere on a dipole geomagnetic field model by projecting field and particle observations onto the model is described. High-latitude field lines are traced between the earth's surface and their intersection with either the equatorial plane or a cross section of the geomagnetic tail, and data from low-altitude orbiting satellites are projected along field lines to the outer magnetosphere. This procedure is analyzed, and the resultant mappings are illustrated. Extension of field lines into the geomagnetic tail and low-altitude determination of the polar cap and cusp are presented. It is noted that while there is good agreement among the various data, more particle measurements are necessary to clear up statistical uncertainties and to facilitate comparison of statistical models.

Fairfield, D. H.↗
NASA NTRS1974

Trajectory selection for the Mariner Jupiter/Saturn 1977 Project

This paper describes the use of decision analysis to facilitate a group decision-making problem in the selection of trajectories for the two spacecraft of the Mariner Jupiter/Saturn 1977 Project. This NASA project includes the participation of some eighty scientists divided by specialization among eleven science teams. A set of thirty-two candidate trajectory pairs was developed by the Project in collaboration with the science teams. Each science team then ordinally ranked and assigned cardinal utility function values to the trajectory pairs. These data and statistics derived from collective choice rules were used by the scientists in selecting the preferred trajectory pair.

Dyer, J. S.↗
NASA NTRS1975

Designing solid propellant pulsed plasma thrusters

In this paper fundamental definitions and a few semiempirical correlations of experimental data of solid propellant pulsed plasma thrusters are used to illustrate the design analysis of such propulsion systems. The design analysis presented facilitates the design of a thruster to meet a specific performance level and provides the spacecraft designer with a methodology to select a pulsed plasma propulsion system to meet his mission requirements.

Guman, W. J.↗
NASA NTRS1974

Choice-reaction time to visual motion with varied levels of simultaneous rotary motion

Twelve airline pilots were studied to determine the effects of whole-body rotation on choice-reaction time to the horizontal motion of a line on a cathode-ray tube. On each trial, one of five levels of visual acceleration and five corresponding proportions of rotary acceleration were presented simultaneously. Reaction time to the visual motion decreased with increasing levels of visual motion and increased with increasing proportions of rotary acceleration. The results conflict with general theories of facilitation during double stimulation but are consistent with neural-clock model of sensory interaction in choice-reaction time.

Clark, B.↗
NASA NTRS1975

Interior structure of Uranus

Critical measurements relative to interior structure which can be made during a spacecraft mission to Uranus are discussed. Models of atmospheric composition, possible magnetic moment, and gravitational harmonics are described, and it is shown that high quality imaging of the atmospheric rotation and determination of the possible magnetic field rotation will facilitate construction of an accurate model of the interior structure of the planet.

Hubbard, W. B.↗
NASA NTRS1975

Interface effects in the dissolution of silicon into thin gold films

The dissolution of crystalline Si and amorphous Si substrates into thin films of evaporated Au was studied with an electron microprobe and scanning electron microscopy. The dissolution pattern was found to be nonuniform along the plane of the surface and dependent on the crystalline orientation of the Si substrate. The dissolution is greatly facilitated when a very thin layer of Pd is evaporated between the Si substrate and the Au film.

Sankur, H.↗