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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 217 records · Page 12

Observations of low-frequency radio emissions in the earth's magnetosphere

Electromagnetic radiation in the earth's magnetosphere was investigated for the frequency range between 10 kHz and 80 kHz, using data from the Minnesota Plasma Wave Experiment aboard the IMP 6 spacecraft. Two types of radio emissions were examined, the first being the nonthermal continuum radiation, and the second, much more impulsive, is the radiation which lies between 10 and 60 kHz. The first type of radiation was found to correlate with the enhancements of the magnetic substorm index AE and to follow the onset of the negative bay feature of the AU index by about 20 min. The second radiation was found to correlate with auroral kilometric radiation (AKR) on a time scale of about 1 min; this radiation was found to have a source direction very near that of the coincident AKR.

Filbert, Paul C.↗

UV Observations of NGC 205

Low resolution IUE observations of the dwarf elliptical galaxy NGC 205 show that the UV spectral energy distribution (SED) of the galaxy is relatively flat. Spectra centered on the nucleus and on a region north of the nucleus show evidence of recent bursts of star formation which contribute strongly to the UV spectral energy distribution. The UV spectra was fit with a composite spectrum based on a Miller-Scalo initial mass function, an underlying older population (modelled using the UV spectrum of 47 Tuc), and an extinction based on a SMC-like extinction cure. This fit implies that the total mass of young stars (with M equal to or greater than 1 solar mass) in the galaxy is approx. 7x10(5) solar mass, which can be compared to the total mass of globular cluster like stars in the galaxy of approx. 8x10(7) solar mass.

Wilcots, Eric M.↗

COSTEP: A comprehensive suprathermal and energetic particle analyzer for SOHO

The group of instruments involved in the COSTEP (comprehensive suprathermal and energetic particle analyzer) project are described. Three sensors, the LION (low energy ion and electron) instrument, the MEICA (medium energy ion composition analyzer) and the EPHIN (electron proton helium instrument) are described. They are designed to analyze particle emissions from the sun over a wide range of species (electrons through iron) and energies (60 KeV/particle to 500 MeV/nucleon). The data collected is used in studying solar and space plasma physics.

Kunow, Horst↗

Advances in lightweight nickel electrode technology

Studies are currently underway to further the development of lightweight nickel electrode technology. Work is focused primarily on the space nickel-hydrogen system and nickel-iron system but is also applicable to the nickel-cadmium and nickel-zinc systems. The goal is to reduce electrode weight while maintaining or improving performance, thereby increasing electrode energy density. Two basic electrode structures are being investigated. The first is the traditional nickel sponge produced from sintered nickel-carbonyl powder. The second is a new material for this application which consists of a non-woven mat of nickel fiber. Electrodes are being manufactured, tested, and evaluated at the electrode and cell level.

Coates, Dwaine↗

NASA Information Sciences and Human Factors Program

Fiscal year 1989 descriptions of technical accomplishments in seven sections are presented: automation and robotics; communications; computer sciences; controls and guidance; data systems; human factors; and sensor technology.

Holcomb, Lee↗

Micro coring apparatus

A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

Collins, David↗

Video Image Communication And Retrieval - Updated

Video Image Communication and Retrieval (VICAR) package of computer programs is general-purpose image-processing software system. Intended for processing data from Jet Propulsion Laboratory's unmanned planetary spacecraft, now used in variety of other applications, including processing of biomedical images, cartography, studies of Earth resources, and geological exploration. Development of newest version of VICAR emphasizes standardized, easily-understood user interface, shield between user and host operating system, and comprehensive array of image-processing capabilities.

Wall, Ray J.↗

NASA information sciences and human factors program

The FY-90 descriptions of technical accomplishments are contained in seven sections: Automation and Robotics, Communications, Computer Sciences, Controls and Guidance, Data Systems, Human Factors, and Sensor Technology.

Lee Holcomb↗

Ultraviolet observations of NGC 205

Low-resolution IUE observations of the dwarf elliptical galaxy NGC 205 show that the UV spectral energy distribution of the galaxy is relatively flat. Spectra centered on the nucleus and on a region north of the nucleus show evidence of recent 'bursts' of star formation which contribute strongly to the UV spectral energy distribution. The UV spectra are fit with a composite spectrum based on a Miller-Scalo initial mass function, an underlying older population and an extinction based on a SMC-like extinction curve. This fit implies that the total mass of young stars in the galaxy is about 700,000 solar mass, which can be compared to the total mass of Population II stars in the galaxy of about 100 million solar mass.

Wilcots, Eric M.↗

Role of eddy pumping in enhancing primary production in the ocean

Eddy pumping is considered to explain the disparity between geochemical estimates and biological measurements of exported production. Episodic nutrient injections from the ocean into the photic zone can be generated by eddy pumping, which biological measurements cannot sample accurately. The enhancement of production is studied with respect to a cyclonic eddy in the subtropical Pacific. A pump-and-probe fluorimeter generates continuous vertical profiles of primary productivity from which the contributions of photochemical and nonphotochemical processes to fluorescence are derived. A significant correlation is observed between the fluorescence measurements and radiocarbon measurements. The results indicate that eddy pumping has an important effect on phytoplankton production and that this production is near the maximum relative specific growth rates. Based on the production enhancement observed in this case, eddy pumping increases total primary production by only 20 percent and does not account for all enhancement.

Falkowski, Paul G.↗

Images from Galileo of the Venus cloud deck

Images of Venus taken at 418 and 986 nm show that the morphology and motions of large-scale features change with depth in the cloud deck. Poleward meridional velocities, seen in both spectral regions, are much reduced in the NIR. In the south polar region the markings in the two wavelength bands are strongly anticorrelated. The images follow the changing state of the upper cloud layer downwind of the subsolar point, and the zonal flowfield shows a longitudinal periodicity that may be coupled to the formation of large-scale planetary waves. No optical lightning was detected.

Belton, Michael J. S.↗

Durable, Low-Surface-Energy Treatments

Chemical treatment for creation of durable, low-surface-energy coatings for glass, ceramics and other protonated surfaces easily applied, and creates very thin semipermanent film with extremely low surface tension. Exhibits excellent stability; surfaces retreated if coating becomes damaged or eroded. Uses include water-repellent surfaces, oil-repellent surfaces, antimigration barriers, corrosion barriers, mold-release agents, and self-cleaning surfaces. Film resists wetting by water, alcohols, hydrocarbon solvents, and silicone oil. Has moderate resistance to abrasion, such as rubbing with cloths, and compression molding to polymers and composite materials.

Willis, Paul B.↗

Tethers in space handbook, second edition

The Tethers in Space Handbook, Second Edition represents an update to the initial volume issued in September 1986. As originally intended, this handbook is designed to serve as a reference manual for policy makers, program managers, educators, engineers, and scientists alike. It contains information for the uninitiated, providing insight into the fundamental behavior of tethers in space. For those familiar with space tethers, it includes a summary of past and ongoing studies and programs, a complete bibliography of tether publications, and names, addresses, and phone numbers of workers in the field. Perhaps its most valuable asset is the brief description of nearly 50 tether applications which have been proposed and analyzed over the past 10 years. The great variety of these applications, from energy generation to boosting satellites to gravity wave detection is an indication that tethers will play a significant part in the future of space development. This edition of the handbook preserves the major characteristics of the original; however, some significant rearrangements and additions have been made. The first section on Tether Programs has been brought up to date, and now includes a description of TSS-2, the aerodynamic NASA/Italian Space Agency (ASI) mission. Tether Applications follows, and this section has been substantially rearranged. First, the index and cross-reference for the applications have been simplified. Also, the categories have changed slightly, with Technology and Test changed to Aerodynamics, and the Constellations category removed. In reality, tether constellations may be applicable to many of the other categories, since it is simply a different way of using tethers. Finally, to separate out those applications which are obviously in the future, a Concepts category has been added. A new section included here on Conference Summaries recognizes the fact that the tether community is growing internationally, and that meetings provide a means of rapid communication and interaction. Finally, the Bibliography section has been considerably updated to include all known references. These are listed by author and by subject and include the papers to be presented at the Third International Conference in May 1989.

Penzo, Paul A.↗

A proposed time transfer experiment between the USA and the South Pacific

This paper describes the concept, architecture and preliminary details of an experiment directc<l towards providing continuous Ultra High Precision (UHP) time transfer between Washington, DC; Salisbury, SA Australia; Orroral Valley, ACT Australia; arid Lower Hutt, New Zealand. It further describes a proposed method of distributing UTC(USNO) at a high level of precision to passive users over a broad area of the South Pacific. The concept is based on active two-way satellite time transfer from the United States Naval Observatory (USNO) to the proposed USNO Master Clock West (MCW) in Wahiwa, HI USA at the 1 nanosecond level using active satellite two-way time transfer augmented by Precise Positioning Service (PPS) of the Global Positioning System (GPS). MCW would act as an intermediate transfer/reference station, again linked to Salisbury at the 1 nanosecond level using active satellite two-way time transfer augmented by PPS GPS. From this point, time would bc distributed within the region by two methods. The first is an existing TV line sync system using an Australian communications satellite (AUSSAT K1) which is useful to the 20 nanosecond level. The second approach is RF ranging and multilateration between Salisbury, Orroral Observatory, Lower Hutt and the AUSSAT B1 and B2 to be launched in 1992. Orroral Observatory will provide precise laser ranging to the AUSSAT B1/B2 retro reflectors which will reduce ephemeris related time transfer errors to below 1 nanosecond. The corrected position will be transmitted by both the time transfer modem and the existing TV line sync dissemination process. Multilateration has the advantage of being an all weather approach and when used with the laser ranging technique will provide a precise measurement of the propagation path delays. This will result in time transfer performance levels on the order of 10 nanoseconds to passive users in both Australia and New Zealand.

John Luck↗

Eagle RTS: A design for a regional transport aircraft

This university design project concerns the Eagle RTS (Regional Transport System), a 66 passenger, twin turboprop aircraft with a range of 836 nautical miles. It will operate with a crew of two pilots and two flight attendents. This aircraft will employ the use of aluminum alloys and composite materials to reduce the aircraft weight and increase aerodynamic efficiency. The Eagle RTS will use narrow body aerodynamics with a canard configuration to improve performance. Leading edge technology will be used in the cockpit to improve flight handling and safety. The Eagle RTS propulsion system will consist of two turboprop engines with a total thrust of approximately 6300 pounds, 3150 pounds thrust per engine, for the cruise configuration. The engines will be mounted on the aft section of the aircraft to increase passenger safety in the event of a propeller failure. Aft mounted engines will also increase the overall efficiency of the aircraft by reducing the aircraft's drag. The Eagle RTS is projected to have a takeoff distance of approximately 4700 feet and a landing distance of 6100 feet. These distances will allow the Eagle RTS to land at the relatively short runways of regional airports.

Bryer, Paul↗

Detection of bearing failure in mechanical devices using neural networks

We present a novel time-domain method for the detection of faulty bearings that has direct applicability to monitoring the health of the turbo pumps on the Space Shuttle Main Engine. A feed-forward neural network was trained to detect modelled roller bearing faults on the basis of the periodicity of impact pulse trains. The network's performance was dependent upon the number of pulses in the network's input window and the signal-to-noise ratio of the input signal. To test the model's validity, we fit the model's parameters to an actual vibration signal generated by a faulty roller element bearing and applied the network trained on this model to detect faults in actual vibration data. When this network was tested on the actual vibration data, it correctly identified the vibration signal as a fault condition 76 percent of the time.

Burne, Richard A.↗

Remote sensing studies of the terrain northwest of Humorum basin

We have used near-infrared reflectance spectra and Earth-based radar data to investigate the composition and origin of the various geologic units northwest of Humorum basin as well as the stratigraphy of the Humorum preimpact target site. The results of our spectral analysis indicate that at least a portion of the inner, mare-bounding ring is composed of pure anorthosite. Other highlands units in the region are dominated by noritic anorthosite. The anorthosites on the inner ring may have been derived from a layer of anorthosite that exists at depth beneath a more pyroxene-rich unit. Both Gassendi G and F craters expose mare material from beneath a highlands-rich surface unit that was emplaced as a result of the Letronne, Gassendi, and other impact events. This ancient basalt unit was emplaced after the formation of Humorum basin but prior to the Orientale impact.

Hawke, B. R.↗

Data systems and computer science programs: Overview

An external review of the Integrated Technology Plan for the Civil Space Program is presented. The topics are presented in viewgraph form and include the following: onboard memory and storage technology; advanced flight computers; special purpose flight processors; onboard networking and testbeds; information archive, access, and retrieval; visualization; neural networks; software engineering; and flight control and operations.

Smith, Paul H.↗