The scientific instruments on Surveyor.
Surveyor scientific instruments and operation on moon, reviewing TV camera, alpha scattering instrument and surface sampler
Le Croissette, D. H.↗
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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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Interaction of slow electrons with surfaces
Slow electrons interaction with periodic and nonperiodic solid surfaces, investigating elastic scattering
Bauer, E.↗
Radar maps of the moon at 70-cm wavelength and their interpretation
Polarized and depolarized radar maps of moon, attributing anomalies and average diffuse component of echoes to scattering behavior of surface and subsurface rocks
Campbell, M. J.↗
Detection of oil spills using 13.3 GHz radar scatterometer
The results of an analysis of 13.3-GHz single polarized scatterometer data collected during NASA/MSC Mission 135, flown on March 16, 1970 are reported. Data were gathered over a crude oil spill on the Gulf of Mexico off the Mississippi Delta. With the aid of RC-8 camera photographs, the scattering cross section was correlated with the extent of the oil spill. The scattering cross section at higher incidence angles decreased by 5 db to 10 db in the presence of the oil spill. This was attributed to oil's damping of small gravity and capillary waves. The composite scattering theory and the scatterometer acquired data were used to obtain an expression of radar scattering over ocean surfaces with oil spills. The study demonstrates that the presence and extent of oil spills can be detected using high frequency radar systems.
Krishen, K.↗
The composite scattering model for radar sea return
A composite scattering model, suitable for explaining the behavior of measured scattering cross sections of the ocean surface, is presented. Furthermore, utilizing this scattering model, the spectrums of the small gravity, gravity-capillary, waves will be predicted for MSA/MSC, 13.3 GHz Scatterometer data.
Krishen, K.↗
Detection of oil spills using a 13.3-GHz radar scatterometer.
This paper describes the results of an analysis of 13.3-GHz single-polarized scatterometer data collected during NASA/MSC mission 135, flown on March 16, 1970. Data were gathered over a crude oil spill on the Gulf of Mexico (test site 128) off the Mississippi delta. With the aid of RC-8 camera photographs the scattering cross section was correlated with the extent of the oil spill. The scattering cross section at higher incidence angles (25 to 50 deg) decreased by 5-10 db in the presence of the oil spill. This was attributed to the damping by oil of small gravity and capillary waves. The composite scattering theory and the scatterometer-acquired data were used to obtain an expression of radar scattering over ocean surfaces with oil spills. The study demonstrates that the presence and extent of oil spills can be detected with high-frequency radar systems.
Krishen, K.↗
Photometry of Comet Kohoutek /1973f/
Data are reported which provide the first large, homogeneous set of photoelectric and infrared photometry obtained for any comet. Assuming an albedo of 0.5 (a high albedo is assumed because of the large ratio of gas to dust in Kohoutek), the diameter of the nucleus of the comet is estimated to be 10 to 15 km. Based on a comparison with the infrared spectrum of Comet Bennett, it was calculated that the latter had about 16 times as much dust as Kohoutek. The data are used to obtain an evaluation of O'Dell's (1971) expression for the albedo of cometary dust grains in terms of the integrated infrared surface brightness and the surface brightness of scattered light in the continuum.
Rieke, G. H.↗
Interpretation of observed cosmic microwave background radiation
It is argued that the 'surface of last scattering' of the observed microwave background radiation corresponds to the distribution of dust in galaxies or protogalaxies with a temperature of about 110 K at the epoch corresponding to Z roughly equal to 40. This is in contrast with the plasma temperature of over 3,000 K at an earlier epoch (Z greater than about 1,000), as given by the canonical model of big bang cosmologies. In view of this, the claim that the microwave background radiation lends strong support to hot big bang cosmologies is without foundation.
Alfven, H.↗
New results from optical polarimetry of Saturn's rings
Linear polarimetry of Saturn's rings, obtained through the period of the 1979 opposition, is presented. The polarisation clearly correlates in direction with the plane containing the Sun, planet and Earth, but not the ring plane. The results are consistent with local scattering on the surface of individual ring bodies, covered with frost
Johnson, P. E.↗
Image contrast of diffraction-limited telescopes for circular incoherent sources of uniform radiance
A simple approximate formula is derived for the background intensity beyond the edge of the image of uniform incoherent circular light source relative to the irradiance near the center of the image. The analysis applies to diffraction-limited telescopes with or without central beam obscuration due to a secondary mirror. Scattering off optical surfaces is neglected. The analysis is expected to be most applicable to spaceborne IR telescopes, for which diffraction can be the major source of off-axis response.
Shackleford, W. L.↗
Radio frequency verification tasks related to a multiple aperture reflector system
The establishment of analytical methods for predicting the electromagnetic performance of multiple offset fed apertures for multiple beam large space antenna systems is highlighted. The development of experimental modeling techniques for verifying the analytical methods used in predicting the effects of surface roughness (pillows), scattering, and aperture coupling on RF performance is discussed.
Campbell, T. G.↗
Anisotropy of the cosmic microwave background radiation
Theoretical predictions of the angular anisotropy in the cosmic microwave background radiation on both small and large angular scales are presented, and the effect of massive neutrinos on both the background radiation anisotropy and on the galaxy correlation function over very large scales is reviewed. Current observations show that the quadrupole anisotropy provides the greatest constraint on theory, and the values for the gravitational potential fluctuations indicate that small amplitude but sufficiently large-scale density fluctuations, both at the present epoch and on the surface of last scattering, can produce significant large angular scale variations in the radiation temperature. Most importantly, it is proposed that the quadrupole moment is most simply and elegantly interpreted in terms of the density fluctuations on very large scales whose presence is inferred from the requirement that an initial fluctuation spectrum is required in order for structure to develop.
Silk, J.↗
Coupling of radiation into thin film modes by means of localized plasma resonances
The interaction between the surface plasmon mode that propagates at a metal dielectric interface and the localized plasma resonances (LPR) is investigated experimentally in Ag-island films. A stair-stepped sample geometry comprising a glass substrate, a continuous 50-nm Ag film, an LiF spacer film of thickness d = 5-60 nm, and an Ag-island film of mass thickness 3 nm is used in near-normal-reflectivity and plasmon-propagation-constant (k) determinations. The results are presented graphically and discussed. The overall shape of the reflectivity curves is found to be characteristic of Ag films, but with a dip at about 400 nm (corresponding to the absorption resonance of the island film) which is most pronounced with d = 25 nm. It is inferred that the island resonances are strongly coupled to a continuous-film dissipative mechanism at this d value. This inference is supported by the fact that the variation in k, correctd for LiF effects and plotted as a function of d, is greatest at around d = 25 nm. The implications of this finding for broad-band coupling into a thin-film mode, LPR enhancement of waveguide nonlinear effects, and new surface-enhanced-Raman-scattering geometries are indicated.
Holland, W. R.↗
Interpretation of the lunar microwave brightness temperature spectrum - Feasibility of orbital heat flow mapping
The feasibility of an orbital mapping of heat flow by means of microwave radiometers is examined on the basis of a detailed model of the lunar regolith. The results obtained are discussed in terms of contributions of physical properties and regolith structure to the spectral signature of lunation-averaged brightness temperatures. Even for regions for which remote heat flow detection is not feasible, detailed interpretations of remote measurements in terms of physical properties and regolith structure could be made by means of the model presented. Surface and subsurface scattering effects are considered in evaluating possible wavelength dependencies of the microwave emissivity.
Keihm, S. J.↗
Electromagnetic scattering theory
Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.
Bird, J. F.↗
Thematic mapper research in the earth sciences: Small scale patches of suspended matter and phytoplankton in the Elbe River Estuary, German Bight and Tidal Flats
A Thematic Mapper (TM) field experiment was followed by a data analysis to determine TM capabilities for analysis of suspended matter and phytoplankton. Factor analysis showed that suspended matter concentration, atmospheric scattering, and sea surface temperature can be retrieved as independent factors which determine the variation in the TM data over water areas. Spectral channels in the near infrared open the possibility of determining the Angstrom exponent better than for the coastal zone color scanner. The suspended matter distribution may then be calculated by the absolute radiance of channel 2 or 3 or the ratio of both. There is no indication of whether separation of chlorophyll is possible. The distribution of suspended matter and sea surface temperature can be observed with the expected fine structure. A good correlation between water depth and suspended matter distribution as found from ship data can now be analyzed for an entire area by the synoptic view of the TM scenes.
Grassl, H.↗
Analysis of Thematic Mapper data for studying the suspended matter distribution in the coastal area of the German Bight (North Sea)
Thematic Mapper data were analyzed with respect to its capability for mapping the complex structure and dynamics of suspended matter distribution in the coastal area of the German Bight (North Sea). Three independent pieces of information were found by factor analysis of all seven TM channels: suspended matter concentration, atmospheric scattering, and sea surface temperature. For the required atmospheric correction, the signal-to-noise ratios of Channels 5 and 7 have to be improved by averaging over 25 x 25 pixels, which also makes it possible to monitor the aerosol optical depth and aerosol type over cloud-free water surfaces. Near-surface suspended matter concentrations may be detected with an accuracy of factor less than 2 by using an algorithm derived from radiative transfer model calculation. The patchiness of suspended matter and its relation to underwater topography was analyzed with autocorrelation and cross-correlation.
Doerffer, R.↗
TV observations of Phobos - First results
From February to March, 1989, Phobos-2 acquired 37 TV images of Phobos at distances from 200 to 1100 km. These images will be used to update the figure model and topographic and geological maps of Phobos, its spectral characteristics and scattering law, the surface composition and texture, and the parameters of the orbital motion and forced libration.
Avanesov, G. A.↗