Some factors affecting electromagnetic detection of lunar subsurface water.
Lunar surface pore water /or ice/ detection by active orbital or surface electromagnetic experiments, noting water effect on reflection coefficient
Jiracek, G. R.↗
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Alpha-particle spectrometer experiment
Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.
Gorenstein, P.↗
Moonquakes.
Although the average rate of seismic energy release within the moon appears to be far below that of the earth, over 100 events believed to be moonquakes have been recorded by the two seismic stations installed on the lunar surface during Apollo missions 12 and 14. With few exceptions, the moonquakes occur at monthly intervals near times of perigee and apogee and show correlations with the longer-term (7-month) lunar gravity variations. The repeating moonquakes are believed to occur at not less than 10 different locations. However, a single focal zone accounts for 80 per cent of the total seismic energy detected. This active zone appears to be 600 kilometers south-southwest of the Apollo 12 and 14 sites and deep within the moon. Each focal zone must be small (less than 10 kilometers in linear dimension) and fixed in location over a 14-month period. Cumulative strain at each location is inferred. Thus, the moonquakes appear to be releasing internal strain of unknown origin, the release being triggered by tidal stresses.
Latham, G.↗
Automatic vehicle location system
An automatic vehicle detection system is disclosed, in which each vehicle whose location is to be detected carries active means which interact with passive elements at each location to be identified. The passive elements comprise a plurality of passive loops arranged in a sequence along the travel direction. Each of the loops is tuned to a chosen frequency so that the sequence of the frequencies defines the location code. As the vehicle traverses the sequence of the loops as it passes over each loop, signals only at the frequency of the loop being passed over are coupled from a vehicle transmitter to a vehicle receiver. The frequencies of the received signals in the receiver produce outputs which together represent a code of the traversed location. The code location is defined by a painted pattern which reflects light to a vehicle carried detector whose output is used to derive the code defined by the pattern.
Hansen, G. R., Jr.↗
Viking on Mars - A preliminary survey
Selection of landing site, observations of Martian topography from orbit, a log of entry into the Martian atmosphere and landing operations, and soil experiments executed at the landing site are recounted. Several photographs overviewing Martian terrain from orbit (1600 to 1900 km up) are shown. Soil sampling and analysis experiments and experiments designed to detect biotic activity (pyrolysis, labeled release of 14-carbon-tagged CO2, gas exchange and vapor chromatography, pyrolytic release) are described and some preliminary results reported. Results on surface geology and chemical composition of the Martian atmosphere are cited.
Young, R. S.↗
NASA's Eastern Regional Remote Sensing Applications Program
The goals of the Eastern Regional Remote Sensing Applications Program are to establish capability for using LANDSAT technology in state institutions and organizations in an operational mode, and to assist in handling new data, introducing new techniques as they become available, and in building and nurturing the technology within the states. Techniques for application development are supported and workshops and demonstrations are provided to pass information on to users. Major areas of project interest are forest inventory, water inventory, and water clarity, and land cover change detection. Another activity is in adopting software, modifying it to work on users' computers, and in identifying hardware that can be used and tied to user computer systems. Involvement of universities as resources for state and local governments is another element of the program.
Cressy, P. J., Jr.↗
A study of topologies and protocols for fiber optic local area network
The emergence of new applications requiring high data traffic necessitates the development of high speed local area networks. Optical fiber is selected as the transmission medium due to its inherent advantages over other possible media and the dual optical bus architecture is shown to be the most suitable topology. Asynchronous access protocols, including token, random, hybrid random/token, and virtual token schemes, are developed and analyzed. Exact expressions for insertion delay and utilization at light and heavy load are derived, and intermediate load behavior is investigated by simulation. A new tokenless adaptive scheme whose control depends only on the detection of activity on the channel is shown to outperform round-robin schemes under uneven loads and multipacket traffic and to perform optimally at light load. An approximate solution to the queueing delay for an oscillating polling scheme under chaining is obtained and results are compared with simulation. Solutions to the problem of building systems with a large number of stations are presented, including maximization of the number of optical couplers, and the use of passive star/bus topologies, bridges and gateways.
Yeh, C.↗
Electrooptic phase modulation gas correlation spectroscopy - A laboratory demonstration
A new gas-correlation spectroscopy technique is described which uses electrooptic phase modulation (EOPM) of atmospheric emission spectra together with a reference cell to selectively detect radiatively active gases. Laboratory results demonstrate that the EOPM gas-correlation technique is a sensitive approach to species abundance measurements, and support the feasibility of an instrument for measurement of winds in the stratosphere and mesosphere using an EOPM. Through the measurement of wind-induced Doppler shifts in the spectra of atmospheric species, this instrument offers a means of monitoring the wind field in the 20-100 km altitude range from a satellite.
Rider, D. M.↗
Investigation of x ray variability in highly active cool stars
Ginga x ray observations of highly active cool star coronae were obtained and analyzed in an effort to better understand the nature of their time variability. The possible types of variability studied included x ray occultations via eclipses in a binary system, rotational modulation of x ray emission, flares, and a search for microflaring. Observation of both sigma(sup 2) CrB and Algol were performed successfully by Ginga. The sigma(sup 2) CrB observations occurred on 27 to 30 June 1988, and the Algol observations on 12 to 14 January 1989. In the sigma(sup 2) CrB observation, simultaneous IUE and Very Large Array (VLA) observations were obtained during part of the Ginga observation. Flaring activity was detected on sigma(sup 2) CrB in the Ginga 1.7 to 11 KeV band and in the IUE microwave region. A large flare on Algol which lasted well over 12 hours was detected, began with a maximum temperature of 65 MK which gradually decayed to 36 MK, and evidence was shown of highly ionized Fe line emission.
Stern, Robert A.↗
A biosensor for cadmium based on bioconvective patterns
An 'in vitro' method for monitoring cadmium, one of the most lethal bivalent heavy metals, can detect biologically active levels. The effects of cadmium tend to concentrate in protozoa far above natural levels and therein begin transferring through freshwater food chains to animals and humans. In a small sample volume (approximately 5 ml) the method uses the toxic response to the protozoa, Tetrahymena pyriformis, to cadmium. The assay relies on macroscopic bioconvective patterns to measure the toxic response, giving a sensitivity better than 1 micro-g/1 and a toxicity threshold to 7 micro-g/1 for Cd(2+). Cadmium hinders pattern formation in a dose-dependent manner. Arrested organism growth arises from slowed division and mutation to non-dividing classes. Unlike previous efforts, this method can be performed in a shallow flow device and does not require electronic or chemical analyses to monitor toxicity.
Noever, David A.↗
Ca II H and K measurements made at Mount Wilson Observatory, 1966-1983
Summaries are presented of the photoelectric measurements of stellar Ca II H and K line intensity made at Mount Wilson Observatory during the years 1966-1983. These results are derived from 65,263 individual observations of 1296 stars. For each star, for each observing season, the maximum, minimum, mean, and variation of the instrumental H and K index 'S' are given, as well as a measurement of the accuracy of observation. A total of 3110 seasonal summaries are reported. Factors which affect the ability to detect stellar activity variations and accurately measure their amplitudes, such as the accuracy of the H and K measurements and scattered light contamination, are discussed. Relations are given which facilitate intercomparison of 'S' values with residual intensities derived from ordinary spectrophotometry, and for converting measurements to absolute fluxes.
Duncan, Douglas K.↗
S Persei: Optical and water maser variability - 1984 to 1990
The M supergiant S Persei was monitored since 1984 optically and since 1987 for water maser emission at 22 GHz. The dozen H2O maser features show complex variations in intensity with many of the features varying independently of one another. Some of the water maser features brightened dramatically at the time of the bright optical maximum observed in 1988 August and again 10 weeks later. It is possible the increase in water maser intensity is related to the ejection of a dust shell near the time of the preceding optical minimum. The intensity variations of the maser spectrum as being produced by an asymmetric distribution of maser spots are interpreted. A double shell of maser spots may be present on the near side of the shell, but appears to be lacking or be occulted on the far side. No chromospheric activity was detected about 10 weeks after optical maximum. A well developed shock is seen in a near-infrared spectrum obtained in 1988 October.
Little-Marenin, I. R.↗
Opening remarks
The year's accomplishments at the onset of the yearly NAPEX meetings are reviewed. Therefore, I will present the last year's accomplishments and the plans for the next year. The studies supported by the Propagation Program during the last year are listed: OLYMPUS data collection and analysis; the ACTS Propagation Program; low elevation angle 11-GHz measurements; satellite broadcast and mobile studies; radiometric techniques; propagation models database; NASA Reference Publication 1274; CCIR activities; fade detection and compensation; rain rate measurements; and information dissemination.
Davarian, Faramaz↗
Wave-particle interaction at the plasmasphere-ring current interface
During the plasmasphere filling process following geomagnetic storms, an outward density decrease of the cold plasma at L = 3-4 is typically observed. When this structure overlaps with the sharp inner edge of the ring current, wave activity is detected at linearly stable phase velocities. The excitation of these waves around the lower hybrid frequency and their effects on the heating of thermal ions is analyzed. It is found that lower hybrid drift waves are most effective at heating lower mass ions, e.g. plasmaspheric H(+), versus He(+), which may be heated more effectively by electromagnetic ion cyclotron waves driven unstable by the ring current loss cone.
Roth, Ilan↗
Identification of a supernova remnant coincident with the soft gamma-ray repeater SGR1806-20
It is shown here that the well-localized soft gamma-ray repeater (SGR) SGR1806-20 coincides with an SNR: the amorphous radio nebula G10.0-0.3. Together with the coincident of SGR0526-66 with the SNR N49, this argues strongly in favor of a neutron-star origin for SGRs. It is suggested that all young pulsars pass through a brief phase of SGR activity. The detection of pulsar-powered synchrotron nebulae in, or pulsations from, the two SNRs coincident with SGRs would confirm this model.
Kulkarni, S. R.↗
ASCA Observation of the Dipping X-Ray Source X1916-053
We present the results of timing and spectral studies of the dipping X-ray source X1916-053, observed by ASCA during its Performance Verification phase. The detected dipping activity is consistent with previous observations, with a period of 3008s and an intermittent secondary dip observed roughly 0.4 out of phase with the primary dip. The energy spectra of different intensity states are fitted with a power law with partial covering fraction absorption and interstellar absorption. The increase in the hardness ratio during the primary and secondary dips, and the increase in the covering fraction and column density with decreasing X-ray intensity, all imply that the dipping is caused by the photo-absorbing materials which have been suggested to be where the accreted flow hits the outer edge of the disk materials. The spectra at all intensity levels show no apparent evidence for Fe or Ne emission lines. This may be due to the low metal abundance in the accretion flow. Alternatively, the X-ray luminosity of the central source may be too weak to excite emission lines, which are assumed to be produced by X-ray photoionization of the disk materials.
Ko, Yuan-Kuen↗
Real-Time Lunar Prospector Data Visualization Using Web-Based Java
The Lunar Prospector was co-developed by NASA Ames Research Center and Lockheed Martin, and was launched on January 6th, 1998. Its mission is to search for water ice and various elements in the Moon's surface, map its magnetic and gravity fields, and detect volcanic activity. For the first time, the World Wide Web is being used to graphically display near-real-time data from a planetary exploration mission to the global public. Science data from the craft's instruments, as well as engineering data for the spacecraft subsystems, are continuously displayed in time-varying XY plots. The craft's current location is displayed relative to the whole Moon, and as an off-craft observer would see in the reference frame of the craft, with the lunar terrain scrolling underneath. These features are implemented as Java applets. Analyzed data (element and mass distribution) is presented as 3D lunar maps using VRML and Javascript. During the development phase, implementations of the Java Virtual Machine were just beginning to mature enough to adequately accommodate our target featureset; incomplete and varying implementations were the biggest bottleneck to our ideal of ubiquitous browser access. Bottlenecks notwithstanding, the reaction from the Internet community was overwhelmingly enthusiastic.
Deardorff, D. Glenn↗
Two Strategies for Microbial Production of an Industrial Enzyme-Alpha-Amylase
Extremophiles are microorganisms that thrive in, from an anthropocentric view, extreme environments including hot springs, soda lakes and arctic water. This ability of survival at extreme conditions has rendered extremophiles to be of interest in astrobiology, evolutionary biology as well as in industrial applications. Of particular interest to the biotechnology industry are the biological catalysts of the extremophiles, the extremozymes, whose unique stabilities at extreme conditions make them potential sources of novel enzymes in industrial applications. There are two major approaches to microbial enzyme production. This entails enzyme isolation directly from the natural host or creating a recombinant expression system whereby the targeted enzyme can be overexpressed in a mesophilic host. We are employing both methods in the effort to produce alpha-amylases from a hyperthermophilic archaeon (Thermococcus) isolated from a hydrothermal vent in the Atlantic Ocean, as well as from alkaliphilic bacteria (Bacillus) isolated from a soda lake in Tanzania. Alpha-amylases catalyze the hydrolysis of internal alpha-1,4-glycosidic linkages in starch to produce smaller sugars. Thermostable alpha-amylases are used in the liquefaction of starch for production of fructose and glucose syrups, whereas alpha-amylases stable at high pH have potential as detergent additives. The alpha-amylase encoding gene from Thermococcus was PCR amplified using carefully designed primers and analyzed using bioinformatics tools such as BLAST and Multiple Sequence Alignment for cloning and expression in E.coli. Four strains of Bacillus were grown in alkaline starch-enriched medium of which the culture supernatant was used as enzyme source. Amylolytic activity was detected using the starch-iodine method.
Bernhardsdotter, Eva C. M. J.↗