Luminous efficiencies of three nickel artificial meteors between 9.8 and 11.4 kilometers per second
Luminous intensity and efficiency parameters for hypersonic reentry of nickel artificial meteors
Bess, T. D.↗
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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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Nondestructive thickness measurement in thin sections of germanium.
Thin Ge wafers nondestructive thickness measurement by IR abborption measurement system using monochromatic He-Ne laser source
Bess, L.↗
A suboptimal approximation to the Kalman filter
Suboptimal estimator to Kalman filter containing scalar weighting factors
Bess, L.↗
An automatic cell counter
Automatic cell counter using analog techniques and standard electronic TV components
Bess, L.↗
Supplementary note on Brownian motion
Brownian motion for large viscosity, deriving modified Fokker-Planck equation based on quasi- Huygens relation
Bess, L.↗
Sonic radiation from a circular piston with impulse excitation
Sonic pressure as function of space and time calculated for radiation from circular piston with impulse excitation
Bess, L.↗
Meteoroid impacts on Mars and the secondary particle environment
The degree to which the thin Martian atmosphere filters out meteoroids approaching the Martian surface was calculated by using a model of the meteoroid environment, a model of the Martian atmosphere, and equations of meteor physics. The secondary particle environment on the surface of Mars caused by the material ejected from meteoroid craters was modeled. The model consists of the mass distribution and the speed distribution of the secondary particles. Calculations were made of the penetration flux for aluminum structures on the Martian surface. The penetration hazard on the Martian surface was compared with the penetration hazard in space near Mars and on the lunar surface.
Humes, D. H.↗
Predicting the probability that earth-orbiting spacecraft will collide with man-made objects in space
A probabilistic approach to the problem of collisions is made possible by basing a model of the relevant characteristics of the total population on the known properties of a fraction of the total. A method of determining collision probability for objects in any two different but potentially intersecting orbits is derived. Collision probabilities for earth-orbital missions are investigated parametrically as a function of orbital characteristics and a hypothetical projection of the results to future orbital missions is discussed.
Brooks, D. R.↗
Size distribution of fragment debris produced by simulated meteoroid impact of spacecraft wall
A laboratory experimental program was conducted to determine the amount of fragment debris produced and its size distribution when simulated spacecraft walls are penetrated by hypervelocity projectiles. Two tests were made in which a spacecraft wall was struck with a small steel and an aluminum projectile, respectively. Results show that most of the fragment debris were irregularly shaped flat plates. The fragment data follow a cumulative number distribution law of the form N = am(exp b) where m is fragment mass and a and b are constants. Orbital lifetimes of most of the fragments were very short, being on the order of a few days.
T Dale Bess↗
Mass distribution of orbiting man-made space debris
Three ways of producing space debris were considered, and data were analyzed to determine mass distributions for man-made space debris. Hypervelocity (3.0 to 4.5 km/sec) projectile impact with a spacecraft wall, high intensity explosions and low intensity explosions were studied. For hypervelocity projectile impact of a spacecraft wall, the number of fragments fits a power law. The number of fragments for both high intensity and low intensity explosions fits an exponential law. However, the number of fragments produced by low intensity explosions is much lower than the number of fragments produced by high intensity explosions. Fragment masses down to 10 to the -7 power gram were produced from hypervelocity impact, but the smallest fragment mass resulting from an explosion appeared to be about 10 mg. Velocities of fragments resulting from hypervelocity impact were about 10 m/sec, and those from low intensity explosions were about 100 m/sec. Velocities of fragments from high intensity explosions were about 3 km/sec.
Bess, T. D.↗
Estimating regional heat flux from scanning radiometer data
Method using matrix approach to determine best linear estimate of total flux consistent with condition of minimum variance proves useful in meteorological studies. It is useful for researchers studying options in scanner design such as scan pattern, scan rate, and radiometer field-of-view.
Bess, T. D.↗
Estimation of regional heat flux from scanning radiometer measurements
The paper presents a statistical method for extracting regional information on the radiative heat flux at the top of the atmosphere from a satellite-borne scanning radiometer. The radiative heat flux distribution is denoted by a double Fourier series with coefficients to be determined from measurements. The method determines, in the sense of minimum variance, the best linear estimator of the total flux over a region. The heat flux distribution is represented by a truncated series which is unbiased.
Bess, T. D.↗
System considerations for an earth radiation budget scanning radiometer
The objective of the scanning radiometer of the Earth Radiation Budget Satellite System is to measure the longwave and reflected shortwave radiation from the earth on a gridwork of approximately 250 km square regions in order to obtain one-month averages of flux with global coverage to an accuracy of 14 W/sq m. A number of considerations in the choice of some of the design parameters of the scanner are discussed. The error sources which must be considered in the design of a scanning radiometer designed to measure regional radiation budget are examined. An analysis of the system performance through spatial averaging is presented. The analysis provides insight into the effects of field of view, time response, onboard processing and spatial averaging.
Smith, G. L.↗
Atmospheric entry and fragmentation of dense meteoroids
Fragmentation characteristics for four artificial meteoroids of high density and high tensile strength with varying size, velocity, and material are investigated. The meteoroids analyzed were lifted to natural meteor altitude by a rocket vehicle system. The meteoroids were then accelerated back into the Earth's atmosphere at natural meteor velocities. Anomalous deceleration of high density meteors was studied. It is shown that anomalies in the deceleration are due to progressive fragmentation of the meteoroids. These anomalies in the deceleration of high density meteoroids are similar to the anomalies that occur in the deceleration of natural meteors, which are generally assumed to be porous and of weak structure.
Bess, T. D.↗
The annual cycle of Earth emitted radiation distribution
Measurements of longwave radiation from the Earth Radiation Budget (ERB) experiment aboard the Nimbus 6 spacecraft have been analyzed to show the annual cycle of the distribution of Earth emitted radiation.
Bess, T. D.↗
System considerations for an earth radiation budget scanning radiometer
Error sources that might affect the earth radiation budget (ERBSI) scanner radiometer are discussed. Effects of sensor time response, spatial averaging by the field of view, onboard processing, and level III averaging are examined, coverage of grid regions is considered, and an analysis procedure for a scanning radiometer is derived. ERBSI consists of a scanning radiometer, sensors, and a solar radiometer, and it is suggested that ERBSI be included in the instrument complement of NOAA operational spacecraft.
Smith, G. L.↗
Deconvolution and analysis of wide-angle longwave radiation data from Nimbus 6 Earth radiation budget experiment for the first year
One year of longwave radiation data from July 1975 through June 1976 from the Nimbus 6 satellite Earth radiation budget experiment is analyzed by representing the radiation field by a spherical harmonic expansion. The data are from the wide field of view instrument. Contour maps of the longwave radiation field and spherical harmonic coefficients to degree 12 and order 12 are presented for a 12 month data period.
Bess, T. D.↗
Deconvolution of wide field-of-view radiometer measurements of earth-emitted radiation. II - Analysis of first year of Nimbus 6 ERB data
The theory of deconvolution considered by Smith and Green (1981) is applied to Nimbus 6 data in order to interpret the data with the maximum obtainable resolution. Attention is given to the data sample, sun-contaminated measurements, the measurement model, the deconvolution, the degree variance, the spherical harmonic coefficients, the geographical distribution of longwave radiation, time histories of zonal coefficients, and the effect of a grid system. Degree variance plots for 12 months of longwave radiation data show that the limit for a spherical harmonic representation of the Nimbus 6 wide field-of-view longwave data is 12th degree. The degree variance plots also reveal that most of the power is in the lower degree terms. Contour maps of the radiation field show the geographical distribution of earth emitted radiant exitance for each month.
Bess, T. D.↗