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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 73 records · Page 4

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NASA NTRS1972

Environmental statement for National Aeronautics and Space Administration, Office of Space Science, launch vehicle and propulsion programs

NASA OSS Launch Vehicle and Propulsion Programs are responsible for the launch of approximately 20 automated science and applications spacecraft per year. These launches are for NASA programs and those of other U. S. government agencies, private organizations, such as the Comsat Corporation, foreign countries, and international organizations. Launches occur from Cape Kennedy, Florida; Vandenberg Air Force Base, California; Wallops Island, Virginia; and the San Marco Platform in the Indian Ocean off Kenya. Spacecraft launched by this program contribute in a variety of ways to the control of and betterment of the environment. Environmental effects caused by the launch vehicles are limited in extent, duration, and intensity and are considered insignificant.

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NASA NTRS1974

Infrared sky noise survey

A 10 micron infrared sky noise survey, which was conducted during the period from June 1, 1970 to June 30, 1974, is reported along with associated electronics and recording equipment which was developed and deployed for periods up to 18 months at various potential or existing infrared observing sites in the U.S., Mexico, and Chile. The results of the data activity are given, and variables are defined which influence the intensity and duration of the sky noise.

Westphal, J. A.↗

NASA NTRS1973

Solar wind and terrestrial atmosphere effects on lunar sample surface composition

Samples returned from the Apollo missions have been shown to have undergone a partial surface oxidation with the degree of oxidation being dependent on the intensity and duration of exposure to a terrestrial or other oxidizing atmosphere. Exposure to atomic hydrogen at room temperature, or molecular hydrogen above 100 C results in a surface reduction. The adsorption of water vapor on a test sample was found to be only slightly dependent on the state of surface oxidation, a situation consistent with the formation of hydroxyl groups on the surface when a sample is exposed to hydrogen. That hydroxyl groups are indeed formed is substantiated by the release of water vapor (and by release of heavy water following exposure to deuterium), indicating that water vapor can be synthesized from solar wind hydrogen and sample oxygen. Observations of trace amounts of methane indicate that the reduction process is by no means restricted to the formation of water vapor.

Cadenhead, D. A.↗

NASA NTRS1976

X-ray emission from high temperature plasmas

The physical processes occurring in plasma focus devices were studied. These devices produce dense high temperature plasmas, which emit X rays of hundreds of KeV energy and one to ten billion neutrons per pulse. The processes in the devices seem related to solar flare phenomena, and would also be of interest for controlled thermonuclear fusion applications. The high intensity, short duration bursts of X rays and neutrons could also possibly be used for pumping nuclear lasers.

Harries, W. L.↗

NASA NTRS1977

High-latitude nitric oxide in the lower thermosphere

High-latitude observations of fluorescent nitric oxide gamma bands were made before and during a strong magnetic storm with the Ogo 4 ultraviolet spectrometer. Brightness measurements of the (1-0) gamma band of nitric oxide indicate a slow buildup of NO during the disturbed period. The NO column density reaches a value as high as a factor of 8 greater than the midlatitude value and shows no correlation with the brightness of the instantaneous aurora. A time-dependent model calculation indicates that the ionization and dissociation of N2 by auroral electrons can increase the NO and N(4-S) densities. This increase is dependent on the intensity and duration of the auroral precipitation and on the branching ratio of N(2-D) production by dissociation of N2. A steady state is not reached for NO until 100,000 sec in an aurora characterized by an energy flux of 10 ergs per sq cm sec. Dissociation by the solar ultraviolet radiation competes with horizontal and vertical transport as a loss process for the nitric oxide produced by the aurora. A high NO(plus)/O2(plus) ratio is to be expected in the period following a strong auroral precipitation.

Gerard, J.-C.↗

NASA NTRS1978

Transient X-ray sources in the galactic plane

Uhuru observations of the galactic plane indicate the presence of four X-ray sources not previously characterized as transient: MX 0836-42, A1918+14, 4U 1730-22, and 4U 1807-10. X-ray light curves as well as positional and spectral information are presented for these sources and for 4U 1908+00, a recurrent transient source. The frequency, duration, and intensity of galactic-plane transients during the Uhuru lifetime are discussed. Transient X-ray sources appear to be divided into two classes based primarily on an observed bimodal spectral temperature distribution.

Cominsky, L.↗

NASA NTRS1979

Preliminary design procedure for insulated structures subjected to transient heating

Minimum-mass designs were obtained for insulated structural panels loaded by a general set of inplane forces and a time dependent temperature. Temperature and stress histories in the structure are given by closed-form solutions, and optimization of the insulation and structural thicknesses is performed by nonlinear mathematical programming techniques. Design calculations are described to evaluate the structural efficiency of eight materials under combined heating and mechanical loads: graphite/polyimide, graphite/epoxy, boron/aluminum, titanium, aluminum, Rene 41, carbon/carbon, and Lockalloy. The effect on design mass of intensity and duration of heating were assessed. Results indicate that an optimum structure may have a temperature response well below the recommended allowable temperature for the material.

Adelman, H. M.↗

NASA NTRS1973

Final Environmental Impact Statement for National Aeronautics and Space Administration Office of Space Science: Sounding Rocket Program

The NASA OSS Sounding Rocket Program is responsible for the launch of approximately 80 science and applications payloads per year. These launches are for NASA programs and those of other U.S. government agencies private industry, universities, foreign countries, and international organizations. NASA launches occur or have occurred from 34 launch sites located throughout the world. Nine of these receive substantial use. Payloads launched by this program contribute in a variety of ways to the control and betterment of the environment (e.g., solar studies). Environmental effects caused by the research vehicles are limited in extent, duration, and intensity and are considered insignificant. There are no short-term alternatives to the current family of sounding rocket vehicles. The possibilities for changes in the family including new stage and sounding rocket developments, are continuously reviewed. Although measurements using high-altitude aircraft and balloons are possible at lower altitudes and using satellites at much higher altitudes, the specific region of the atmosphere between about 40 and 200 km cannot be reached in any other way. Sounding rockets can be launched simultaneously from several points and can be used in response to time-related phenomena.

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NASA NTRS1980

Effects of centrifugation on gonadal and adrenocortical steroids in rats

Many endocrine systems are sensitive to external changes in the environment. Both the pituitary adrenal and pituitary gonadal systems are affected by stress including centrifugation stress. The effect of centrifugation on the pituitary gonadal and pituitary adrenocortical systems was examined by measuring the gonadal and adrenal steroids in the plasma and brain following different duration and intensity of centrifugation stress in rats. Two studies were completed and the results are presented. The second study was carried out to describe the developmental changes of brain, plasma and testicular testosterone and dihydrotestosterone in Sprague Dawley rats so that the effect of centrifugation stress on the pituitary gonadal syatem could be better evaluated in future studies.

Kakihana, R.↗

NASA NTRS1981

Shock-associated low-energy ion enhancements observed by Voyagers 1 and 2

Observations of shock-associated ion enhancements at energies of not less than 30 keV are presented from data gathered by Voyagers 1 and 2. Observations include examples of energetic storm particle events associated with flare-produced shocks and examples of corotating particle events (CPE) associated with forward and reverse shocks that bound corotating interaction regions in the outer heliosphere. Most of the CPE have recurrent double-peaked intensity enhancements showing little or no velocity dispersion at peak intensities, time durations of several days, and soft energy spectra extending up to 5 MeV/nucleon. The lowest energy ion enhancements are confined mainly downstream of the corotating interaction regions with the magnitude and duration of the upstream enhancements increasing with increasing ion energy. The observations are consistent with the dynamical and kinematical effects expected when low energy ions are accelerated at quasi-perpendicular shocks.

Decker, R. B.↗

NASA NTRS1984

Guidelines for assessment and control of noise

There is an obvious need for guidelines and standards with respect to what intensities and durations of noise exposure is considered incompatible with the health and well-being of the people exposed. These guidelines would presumably be useful for the zoning of land areas to avoid overexposure of people to environmental noise and for legislative-judicial adjudication of liabilities for possible damages to individuals and groups from exposure to noise. A number of guidelines for noise exposure were promulgated by various governmental agencies for these purposes. Partly because of the need for an integrated and consistent program of noise control for all elements of the government, the United States Environmental Protection Agency (EPA) was established. In addition to previously issuing some specific documents regarding safe noise exposure limits, the EPA joined several Federal operating and regulatory agencies in issuing guidelines for considering noise in land use planning and control. Government guideline documents, as well as some issued by non-government agencies, are examined. Also, newly proposed guidelines for noise in residential areas, and the scientific basis for these guidelines, are presented.

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NASA NTRS1983

Environmental effects of Shuttle launch and landing

The areas of concern were the toxic exhaust cloud produced by Shuttle launch, the effect of launch operations on the total ecology, and the sonic boom produced by Orbiter re-entry. Wet acidic dust fell from the exhaust cloud for about ten minutes after launch. The fallout was not entirely unexpected, but the intensity and duration was larger than anticipated. The fallout material is not considered a significant health hazard. Previously announced in STAR as N82-15729

Potter, A. E.↗

NASA NTRS1983

A model study of the effects of intermittent loss on odd nitrogen concentrations in the lower troposphere

A time-dependent box model of the lower troposphere which includes a description of photochemical and physical processes has been developed. This model has been applied to the calculation of nitric acid and NO(x)(NO + NO2) concentrations over a diurnal cycle which includes precipitation. Nitric acid concentrations and the HNO3/NO(x) ratio are found to be highly variable under the assumptions regarding the frequency, duration, and intensity of precipitation employed in this model. The chemistry of odd nitrogen compounds during the night is potentially important in establishing the level of nitric acid in the lower troposphere. These calculations also indicate that relatively large errors may occur when the continuity equation describing nitric acid variations is averaged over a diurnal cycle which includes precipitation. Interpretation of simultaneous measurements of HNO3 and NO(x) will require some knowledge of the history of the observed air mass and may require an improved understanding of nighttime odd nitrogen chemistry.

Stewart, R. W.↗

NASA NTRS1985

In situ orbital debris experiment concepts

Implementation of the radar, lidar and passive optical remote sensing concepts for measuring space debris from an Earth orbiting platform was investigated. Each system was compared for their requirements on the host platform, their performance relative to the space debris measurement program and the estimated cost of developing each concept into a flight instrument. It is found that the radar and lidar systems offer the greatest versatility and accuracy since they control the direction, intensity and duration of the energy incident on the target object. The performance of the passive optical system is determined by the capability of the detector and by the baseline separation of the telescopes, which requires the use of an on-orbit deployment mechanism. The passive optical concept provides the largest total event rae, and includes significant detections of particle sizes greater than 10 cm to allow correlation with ground based observations of the larger particles. The event rate for the radar system is relatively constant with particle while the lidar system is slightly biased toward the smaller sizes. These event rate differences result from a combination of the debris flux size distribution and the variation of sensitive detection area with particle size for the three concepts.

Neste, S. L.↗

NASA NTRS1988

Some statistics of solar radio bursts of spectral types II and IV

The properties of meter wavelength solar emissions are studied using a sample of all type II and type IV radio bursts detected by the Culgoora radio observatory during 1968-1983. It is found that type IV emission generally occurs in conjunction with type II emission. For type III bursts preceding type II bursts, the delay to type II onset is 6.5 min on average. The intensities and durations of type II bursts are not dependent on the heliolongitude of the associated flares.

Cane, H. V.↗

NASA NTRS1989

The interannual variability of polar stratospheric clouds and related parameters in Antarctica during September and October

Antarctic polar stratospheric cloud (PSC) sightings by the orbiting SAM II sensor during September and October show a pronounced quasi-biennial oscillation (QBO) signal, and October sightings have increased markedly over the past 10 years in years of westerly QBO phase. The QBO in PSC frequency is likely to affect the rate of Antarctic heterogeneous chemical processes and, hence, ozone depletion. Studies of the observed long-term temperature trend suggest that the decadal PSC trend probably results from the ozone decline, through its effect on stratospheric heating rates. A more detailed analysis of data from 1986 to 1987 shows that there were more PSCs in 1987, and that they persisted much later into the spring season as compared to 1986. Qualitatively similar behavior was found for the OClO column abundances and 18-km ozone depletion observed at McMurdo Station during these 2 years. These observations suggest that both the intensity and duration of heterogeneous chemical processes are likely greater during colder OBQ-westerly phase years.

Poole, Lamont R.↗

NASA NTRS1990

Gradational epochs on Mars - Evidence from west-northwest of Isidis Basin and Electris

An account is given of the characteristics of Martian regions which may be adduced as evidence for enhanced gradation. The crater statistics for these regional surfaces are sufficiently different from those of proximate units with little evidence of modification to suggest, through comprehensive correlation, that a common pattern of modification to crater statistics may be a reflection of common epochs of enhanced gradation. If that be the case, then these areas' gradation occurred during a series of epochs of local-to-global extent whose duration and intensity decreased through time, following the last major impacts.

Grant, John A.↗

NASA NTRS1990

Exercise during long term exposure to space: Value of exercise during space exploration

There appear to be two general physiological reasons why exercise will be beneficial to space travelers who will experience a weightless and isolated environment for many months or a few years: (1) to alleviate or prevent tissue atrophy (principally bone and muscle), to maintain cardiovascular function, and to prevent deleterious changes in extracellular and cellular fluid volumes and plasma constituents, especially electrolytes; and (2) to maintain whole organism functional physical and physiological status with special reference to neuromuscular coordination (physical skill) and physical fitness (muscle strength and power, flexibility, and aerobic endurance). The latter reason also relates well to the ability of the crew members to resist both general and local fatigue and thus ensure consistent physical performance. Various forms of exercise, performed regularly, could help alleviate boredom and assist the travelers in coping with stress, anxiety, and depression. The type, frequency, duration and intensity of exercise and ways of ensuring that crew members engage in it are discussed.

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