Chemical studies on the orgin of life and criteria for detection of extraterrestrial life
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Source requirements for the fluctuation orgin of cosmic radiation
Source requirement for fluctuation origin of cosmic radiation in model
Wayland, J. R.↗
STRATCOM-8 scientific objectives and mission orginization
Stratospheric photochemistry was studied, with emphasis on the Ozone-NOx-ultraviolet flux interactions, but also including members of the chlorine, water vapor, and carbon-containing families. Secondary objectives include: (1) study of the balloon environment, (2) comparison of independent measurements of ozone and of NO, (3) development of new sensor systems; and (4) some measurements for exploratory purposes. Most, but not all, systems and instruments performed as planned, and it is believed that data are available to achieve most of the planned scientific and engineering objectives. The emphasis on photochemistry in the 35 to 40 km region is greater than anticipated, and observations are more complete for sunset than for sunrise. The planned instruments and a summary of the flight operations is discussed partly for the mutual information of those participating and partly for the wider scientific community.
Reed, E. I.↗
Instabilities orginating from suction holes used for Laminar Flow Control (LFC)
A small-scale wind tunnel previously used for turbulent boundary layer studies has been modified for experiments in laminar flow control. The facility incorporates suction through interchangeable porous test surfaces which are used to stabilize the boundary layer and delay transition to turbulent flow. The thin porous test surfaces are supported by a baffled plenum chamber box which also acts to gather the flow through the surface into tubes which are routed to a high pressure fan. An elliptic leading edge is attached to the assembly to establish a new layer on the test plate. A slot is used to remove the test section flow below the leading edge. The test section was lengthened and fitted with a new ceiling. Substantial modifications were also made to the 3D probe traverse. Detailed studies have been made using isolated holes to explore the underlying instability mechanisms. The suction is perturbed harmonically and data are averaged on the basis of the phase of the disturbance. Conditions corresponding to strong suction and without suction have been studied. In both cases, 3D contour surfaces in the vicinity of the hole show highly three-dimensional T-S waves that fan out away from the hole with streamwise distance. With suction, the perturbations on the centerline are much stronger and decay less rapidly, while the far field is similar to the case without suction. Downstream the contour surfaces of the bow-shaped TS waves develop spanwise irregularities which eventually form into clumps. The contours remain smooth when suction is not applied. Even without suction, the harmonic point source is challenging for CFD; e.g. DNS has been used for streamwise growth. With suction, grid resources are consumed by the hole and this makes DNS even more expensive. Limited DNS results so far indicate that the vortices which emanate from suction holes appear to be stable. The spanwise clumping observed in the experiment is evidence of a secondary instability that could be associated with suction vortices. A typical porous surface for LFC consists of 0.002 inch diameter holes with 0.020 inch grid spacing L, which is too small to resolve disturbances. A 20:1 scale porous test surface has been machined for improved spatial resolution while the L/d is still representative of flight conditions. Designers of porous surfaces use Goldsmith's criterion to minimize crossstream interaction. However nothing is known about the streamwise interactions. Results using two holes, aligned but displaced in the streamwise direction, indicate that partial TS wave cancellation is possible, depending on the hole spacing and disturbance frequency. Using DNS for streamwise interaction studies will be prohibitively expensive if linear superposition cannot be used for the multiple holes.
Watmuff, Jonathan H.↗
Orgin of the Marsden and Krachet groups of sunskirting comets. I. association with comet 96P / machholz and its inteplanetary complex
Of the three major groups of comets approaching the Sun to between 6 and 12 solar radii and discovered with the coronagraphs on board SOHO, we investigate the Marsden and Kracht groups.We call these comets ''sunskirters'' to distinguish them from the Kreutz system sungrazers. Our objective is to understand the origin, history, and orbital evolution of the two groups.
asteroids↗
NASA's Orgins Space Telescope Mission and Its Synergies with SOFIA
The Origins Space Telescope (OST) is the mission concept for the Far Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. The science program that has been selected to drive the OST performance requirements is broad, covering four main themes: Charting the Rise of Metals, Dust, and the First Galaxies; Unveiling the Growth of Black Holes and Galaxies Over Cosmic Time; Tracing the Signatures of Life and the Ingredients of Habitable Worlds; and Characterizing Small Bodies in the Solar System. The OST telescope itself will have a primary mirror diameter of 8-15 m (depending on the launch vehicle that is selected), will be diffraction-limited at 40m, and will be actively cooled to approximately 5K. Five science instruments have been base-lined for the observatory: a heterodyne instrument covering 150-500 m with a spectral resolving power of R1e7; a low-spectral resolution (R500) spectrometer covering 35-500 m; a high-spectral resolution (R1e5) spectrometer covering 50-500 m; a far-infrared imager (R15) covering 35-500m; and a mid-infrared imagerspectrometer (R15-500) covering 6-40m. In addition to having a vastly higher sensitivity than the corresponding SOFIA instrumentation that will allow more detailed follow-up of SOFIAs discoveries, the OST mission will be configured to provide efficient large-area mapping, which will further complement SOFIAs science capabilities by providing new targets for study by SOFIA. Furthermore, new SOFIA instruments can provide an excellent testbed for the advanced far-infrared detector technologies what will be required to achieve the anticipated OST performance.
Mission↗
An investigation of volcanic depressions. Part 1: Airfall and intrusive pyroclastic deposits. Part 2: Subaerial pyroclastic flows and their deposits
Pyroclastic ejecta and the deposits they form were classified in many ways, and many interpretations were given to individual terms. Some classifications are based on the modes of orgin and deposition of the ejecta; others emphasized the chemical and physical composition of the ejecta. Particle-size was used as the prime basis of subdivision, and the same size-limits were used as those employed in the classification of sediments and sedimentary rocks.
Williams, H.↗
When the beachhopper looks at the moon: The moon compass hypothesis
The function of moon position for shoreline orientation by talitrids is investigated. Three major results were found: (1) Observed cases of compensation for changes in the direction of the moon are based on physiological rhythm with a period of about 25 hours which can persist for at least several days under constant conditions. (2) The zeitgeber for physiological rhythm may be either moonlight or some other factor associated with the tides. (3) If talitrids are long removed from environmental entrainment, either artifically or naturally, the internal rhythm no longer exerts an appreciable influence on the angle of lunar orientation; in such cases the system deteriorates into constant angle orientation, with an angle which is determined by the beach orgin, but may be modified by lighting conditions.
Enright, J. T.↗
Goddard contributions to the Los Alamos Conference on Transient Cosmic Gamma and X-ray Sources
Conference papers, covering the orgin and instrumentation for measuring the position of cosmic gamma ray bursts, are presented. Summaries cover gamma ray detectors, energy speectra, and the stellar super flare hypothesis.
Source record↗
Cosmic soft gamma-ray bursts and the stellar super-flare hypothesis
Possible alternatives to the supernovae theory on the orgin of cosmic ray bursts are examined. In particular, the possibility that these outbursts are simply giant versions of the X-ray burst typically seen in solar flares is investigated. It was suggested that the outbursts are caused by the bresstrahlung of electrons accelerated to high energies in a stellar flare event.
Stecker, F. W.↗
The astrophysics of the diffuse background of X-rays and gamma rays
The orgin of diffuse X-ray and gamma ray background and some of the astrophysical implications of such a radiation background are discussed. Data show that gamma and X-rays come from thermal bremsstrahlung, neutral pion decay, and compton scattering of thermal protons. The range of energies studied extend from approximately 10 0 eV to approximately 10 to the 8th power eV.
Cowsik, R.↗
Matter-antimatter cosmology
Mechanisms responsible for the orgin and separation of matter and antimatter in the universe are discussed. Particular attention was given to coalesence. This mechanism involves annihilation production of along the boundary of matter-antimatter, high energy photons, electrons, and positrons. These particles together with secondary particles which they put into motion by collisions, carry their momentum to the matter or antimatter fluid. Coalescence and annihilation rates are discussed.
Omnes, R.↗
The isotopes of H and He in solar cosmic rays
The isotopic composition of H and He in solar cosmic rays was studied with the solar galactic cosmic ray experiment on the Orbiting Geophysical Observatory, OGO-6. Averaging over 20 days of data from seven flare events during 1969, the ratios He-3/-He-4 = 0.10 + or - 0.02, D/H (76) .0003 and T/H (76) .0001 in the 4 to 5 MeV/nucleon energy range were obtained. In addition, large variations were found in the relative abundance of He-3 from event of event, with a maximum ratio of He-3/He-4 = 0.26 + or - 0.08 observed on October 14 and 15, 1969. The relative abundance of He-3 and D during this event does not seem to be consistent with existing calculations of the nuclear interaction orgin of these isotopes.
Garrard, T. L.↗
Field mapping for heat capacity mapping determinations: Ground support for airborne thermal surveys
Thermal models independently derived by Watson, Outcalt, and Rosema were compared using similar input data and found to yield very different results. Each model has a varying degree of sensitivity to any specified parameter. Data collected at Pisgah Crater-Lavic Lake was re-examined to indicate serious discrepancy in results for thermal inertia from Jet Lab Propulsion Laboratory calculations, when made using the same orginal data sets.
Lyon, R. J. P.↗
Spatial land-use inventory, modeling, and projection/Denver metropolitan area, with inputs from existing maps, airphotos, and LANDSAT imagery
A landscape model was constructed with 34 land-use, physiographic, socioeconomic, and transportation maps. A simple Markov land-use trend model was constructed from observed rates of change and nonchange from photointerpreted 1963 and 1970 airphotos. Seven multivariate land-use projection models predicting 1970 spatial land-use changes achieved accuracies from 42 to 57 percent. A final modeling strategy was designed, which combines both Markov trend and multivariate spatial projection processes. Landsat-1 image preprocessing included geometric rectification/resampling, spectral-band, and band/insolation ratioing operations. A new, systematic grid-sampled point training-set approach proved to be useful when tested on the four orginal MSS bands, ten image bands and ratios, and all 48 image and map variables (less land use). Ten variable accuracy was raised over 15 percentage points from 38.4 to 53.9 percent, with the use of the 31 ancillary variables. A land-use classification map was produced with an optimal ten-channel subset of four image bands and six ancillary map variables. Point-by-point verification of 331,776 points against a 1972/1973 U.S. Geological Survey (UGSG) land-use map prepared with airphotos and the same classification scheme showed average first-, second-, and third-order accuracies of 76.3, 58.4, and 33.0 percent, respectively.
Tom, C.↗
An initial assessment of the performance achieved by the Seasat-1 radar altimeter
The results of an initial on-orbit engineering assessment of the performance achieved by the radar altimeter system flown on SEASAT-1 are presented. Additionally, the general design characteristics of this system are discussed and illustrations of altimeter data product are provided. The instrument consists of a 13.5 GHz monostatic radar system that tracks in range only using a one meter parabolic antenna pointed at the satellite nadir. Two of its unique features are a linear FM transmitter with 320 MHz bandwidth which yields a 3.125 nanosecond time delay resolution, and microprocessor implemented closed loop range tracking, automatic gain control (AGC), and real time estimation of significant wave height (SWH). Results presented show that the altimeter generally performed in accordance with its orginal performance requirments of measuring altitude to a precision of less the 10 cm RMS, significant wave height to an accuracy of + or - 0.5 m or 10%, whichever is greater, and ocean backscatter coefficient to an accuracy of + or - 1 db, all over an SWH range of 1 to 20 meters.
Townsend, W. F.↗