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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Gas-chromatographic measurements of atmospheric CF2Cl2, CFCl3 and N2O in Antarctica

Stratospheric ozone is produced photochemically and destroyed by reactions with such minor constituents as O, NOx, HOx, and ClOx. Chlorofluoromethanes (CF2Cl2 and CFCl3) and dinitrogen oxide (NwO) are considered as major sources of the stratospheric ClOx and NOx, respectively. It is well known that CF2Cl2 and CFCl3 are released only by man's activities, and are being accumulated in the troposphere. In order to assess the influence of these compounds on the natural ozone balance these gases have been measured over Japan since 1978. Measurements of Antarctic air samples are also indispensable to understanding the global distributions of these gases, because most CF2Cl2 and CFCl3 have been released in the Northern Hemisphere. Antarctic air samples were obtained by the 23rd, 24th and 25th Japanese Antarctic Research Expeditions, and analyzed by a gas-chromatographic method using an electron capture detector. Three experimental results were obtained: (1) latitudinal distribution of these gases from Tokyo to Syowa Station (69.0 deg S, 39.6 deg E), (2) time trends at Syowa Station, and (3) vertical distributions over Syowa Station. Results are reported.

Hirota, H.↗
NASA NTRS1985

Research activities on Antarctic middle atmosphere by JARE 25th team

The Antarctic Middle Atmosphere (AMA)-Japan research project was set about by the JARE (Japan Antarctic Research Expedition) 23rd team in 1982, and since then the JARE-24th and JARE-25th teams have been continuing reseach on the Antarctic Middle Atmosphere. Results gained by JARE-25th team members who are now working at Syowa Station (69.99 deg S, 39.35 deg E), Antarctica are presented. In their activities satellite measurements (Exos-C) and rocket soundings are used. Three rockets of the S310 type were launched at Syowa Station (Geomagnetic Latitude = 69.9 deg S) for the purpose of directly observing the electron density, ionospheric temperature, auroral patterns and luminosity in situ. Vertical profiles of electron density and auroral emission 4278A measured by three rockets are compared.

Hirasawa, T.↗
NASA NTRS1985

Observation of total ozone fields in the Antarctic atmosphere from TOVS of TIROS-N/NOAA

Total ozone amounts in the Antarctic atmosphere are derived from infrared nadir scanning data of TIROS Operational Vertical Sounder (TOVS) of NOAA-6 and 7. HRPT data of the TIROS-N NOAA series of meteorological satellites have been received at Syowa Station (69 deg 00'S, 39 deg 35'E), Antarctica, about once a day since February 1980, by the Japanese Antarctic Research Expedition. HIRS/2 data of TOVS were extracted from HRPT data after being converted into CCT at the home institute. Total ozone amounts were derived for the northeastern part of the Antarctic, for about 100 orbits in 1981 and 1982.

Yamanouchi, T.↗
NASA NTRS1986

Meteoritic ablation and fusion spherules in Antarctic ice

In the course of two Antarctic expeditions in 1980/1981 and 1982/1983 approximately 4 metric tons of documented ice samples were collected from the Atka Bay Ice Shelf, Antarctica, and subsequently shipped for cosmic dust studies. After filtration of the melt water, approximately 700 Antarctic spherules (AAS) in the size range of 5 to 500 microns were handpicked from the filter residue under optical microscopes. For the chemical investigation of single dust grains the following techniques were applied: scanning electron microscopy (SEM), X-ray analysis (EDAX), instrumental neutron activation analysis (INAA), laser microprobe mass analysis (LAMMA), and accelerator mass spectroscopy (AMS). For more than 95% of the total mass the bulk and trace elements were determined in single grain analyses using EDAX, INAA, and LAMMA. The element pattern of the dust particles was compared with that of typical terrestrial material and meteoritic matter. The majority of the spherules exhibited elemental compositions compatible with meteoritic element patterns.

Thiel, K.↗
NASA NTRS1986

Sonic-boom research: Selected bibliography with annotation

Citations of selected documents are included which represent the state of the art of technology in each of the following subject areas: prediction, measurement, and minimization of steady-flight sonic booms; prediction and measurement of accelerating-flight sonic booms; sonic-boom propagation; the effects of sonic booms on people, communities, structures, animals, birds, and terrain; and sonic-boom simulator technology. Documents are listed in chronological order in each section of the paper, with key documents and associated annotation listed first. The sources are given along with acquisition numbers, when available, to expedite the acquisition of copies of the documents.

Hubbard, H. H.↗
NASA NTRS1986

Cytogenetic analyses of peripheral lymphocytes subjected to simulated solar flare radiation

Solar flare protons share many radiological health characteristics of the inner Van Allen Belt protons, and both types of radiation pose serious dangers to a number of missions planned. It is appropriate to evaluate crew dose determination procedures in terms of the type of radiation responsible for the major part of the projected exposure, i.e., protons in the neighborhood of 100 MeV. Monitoring chromosome abnormalities in peripheral lymphocytes is one method to determine an individual's accumulated radiation dosage. Cell culture and harvest is a relatively simple procedure and is well within the capabilities of a station health facility, but the evaluation of prepared microscopic slides is a time consuming and subjective procedure. This project is part of an effort to demonstrate the utility of automated image processing and evaluation procedures in expediting dose evaluation. The initial goal of this project is to produce a set of reference chromosome spreads produced from control lymphocytes and from lymphocytes exposed in whole blood to protons or gamma rays. The results of manual and automated aberration scoring will ultimately be compared to test for systematic differences between the two evaluation procedures and between the two radiation qualities. Proton irradiations are performed at the University of Texas Health Science Center at Houston Cyclotron Facility. Proton dosimetry is supplemented by TLD packets from and by assay of short-lived proton activation products in the irradiation blood samples.

Prichard, H. M.↗
NASA NTRS1985

The Space Station program definition and preliminary systems design - Recent developments

It is pointed out that space stations represent a major vehicle for accomplishing many things mankind envisions for space activities. Thus, space stations have become necessary stepping-off points for deep-space expeditions, and it is expected that they will lead eventually to the permanent occupancy of another planet. The present paper provides a report regarding planning activities in the U.S. and in other countries which have made significant progress in making a permanent Space Station a reality. The Space Station will consist of a manned base and associated platforms, as well as collateral support equipment. The purpose of the program definition and preliminary design activities (Phase B) is to arrive at the baseline configuration before initiating actual hardware development. Details of the program plan are discussed along with user considerations in design, the commercialization of space, design issues, operations, and Space Station evolution.

Freitag, R. F.↗
NASA NTRS1986

Accurate solutions for transonic viscous flow over finite wings

An explicit multistage Runge-Kutta type time-stepping scheme is used for solving the three-dimensional, compressible, thin-layer Navier-Stokes equations. A finite-volume formulation is employed to facilitate treatment of complex grid topologies encountered in three-dimensional calculations. Convergence to steady state is expedited through usage of acceleration techniques. Further numerical efficiency is achieved through vectorization of the computer code. The accuracy of the overall scheme is evaluated by comparing the computed solutions with the experimental data for a finite wing under different test conditions in the transonic regime. A grid refinement study ir conducted to estimate the grid requirements for adequate resolution of salient features of such flows.

Vatsa, V. N.↗
NASA NTRS1986

Mars sample return mission options (1996-2005)

Missions to the surface of Mars, carrying a Rover and having a sample return capability, constitute another logical step in the exploration of that planet in the late 1990's. Results of a recent study are described. A comparison of viable mission options, involving: retropropulsion vs. aerobraking/aeromaneuvering, direct return vs. Mars orbit rendezous, as well as the future potential of 'in-situ propellant production', is presented. An overview of a variety of scenarios of unmanned expeditions to Mars and their subsequent return to earth, within the addressed time period, is provided.

Sergeyevsky, A. B.↗
NASA NTRS1986

Space technology today

The current status of major NASA programs and planning efforts is surveyed. Consideration is given to space-sciences programs (IRAS, SIRTF, Space Telescope, and planetary probes), applications programs (terrestrial remote sensing, communication, and meteorology), manned spacecraft, the STS, the Space Station, space commercialization efforts (materials processing and bioprocessing), and the feasibility of permanent lunar bases and manned Mars expeditions. Photographs and drawings are included.

Cohen, A.↗
NASA NTRS1986

Lidar observation of the mesospheric sodium layer in Antarctica

The mesospheric sodium layer has been observed at Syowa Station in Antarctica during the wintering period of the 26th Japanese Antarctic Research Expedition. A lidar observation of the polar middle atmosphere at the station has been performed as a part of the Middle Atmosphere Program since 1983. At first stratospheric aerosols have been observed by the system based on a ruby laser. In 1985 a new transmitting system consisting of a tunable dye laser was added to that system to observe the sodium layer, too. The characteristics of the lidar system are given. The results of the mesospheric sodium layer observed on 42 nights during the period from March to October, 1985 are also given.

Nomura, A.↗
NASA NTRS1986

High resolution imaging

Diffraction-limited telescopic observations were obtained of solar system objects and a program of research into Uranus, Neptune, Pluto and the asteroids based upon the data obtained was persued. Two camera systems appropriate for this work were developed. Most importantly, the PAPA photon address camera was developed and proven. Algorithms were developed for both phase and amplitude recovery and were validated on theoretical and laboratory data and to a limited extent on telescopic data. A laboratory simulator was constructed that was used for development but is also available for controlled investigation of image reconstruction. During 1985 two successful expeditions were made to Hawaii and Cerro Tololo and a large body of data on Pluto, Uranus, Neptune and two asteroids are on tape.

Goody, R.↗
NASA NTRS1987

Shuttle ground operations efficiencies/technologies study. Volume 4: Preliminary Issues Database (PIDB) catalog

The Preliminary Issues Database (PIDB) was assembled very early in the study as one of the fundamental tools to be used throughout the study. Data was acquired from a variety of sources and compiled in such a way that the data could be easily sorted in accordance with a number of different analytical objectives. The system was computerized to significantly expedite sorting and make it more usable. The information contained in the PIDB is summarized and the reader is provided with the capability to manually find items of interest.

Scholz, A. L.↗
NASA NTRS1986

Engineering the Voyager Uranus mission

Several factors that affected the continuing expedition of Voyager 2 to Uranus are discussed. The hydrazine propellant and electrical power supplies on the spacecraft, and the radio signal strength and sun sensor and star tracker sensitivities are examined. The use of the on-board computer to steady the spacecraft and reduce image smear is described. The Voyager employs radiometric and optical data to navigate. The changes required to improve the transmission capabilities of the spacecraft and to eliminate the on-board hardware failures are analyzed.

Laeser, R. P.↗
NASA NTRS1986

Accurate determination of the fine-structure intervals in the 3P ground states of C-13 and C-12 by far-infrared laser magnetic resonance

Accurate values are presented for the fine-structure intervals in the 3P ground state of neutral atomic C-12 and C-13 as obtained from laser magnetic resonance spectroscopy. The rigorous analysis of C-13 hyperfine structure, the measurement of resonant fields for C-12 transitions at several additional far-infrared laser frequencies, and the increased precision of the C-12 measurements, permit significant improvement in the evaluation of these energies relative to earlier work. These results will expedite the direct and precise measurement of these transitions in interstellar sources and should assist in the determination of the interstellar C-12/C-13 abundance ratio.

Cooksy, A. L.↗
NASA NTRS1987

Causes and effects of a hole

Preliminary results from the U.S. National Ozone Expedition (NOZE) to Antarctica are reviewed. The NOZE ozonesonde measurements showed significant vertical structure in the hole, with 80 percent depletion in some of the 1 km layers but only 20 percent in adjacent layers. The depletion was confined to the 12-20 km region, beginning first at higher altitude and progressing downward. This is strong evidence against the theory that the ozone hole is due to solar activity producing odd nitrogen at high altitudes which is transported downwards, leading to enhanced odd-nitrogen catalytic cycles that destroy ozone. Nitrous oxide data show unusually low concentrations within the polar vortex, which is evidence against the theory that the hole is caused by a purely dynamical mechanism in which rising air motions within the polar vortex lead to reduced column densities of ozone. It is tentatively concluded that a chemical mechanism involving man-made chlorofluorocarbons is the likely cause of ozone depletion in the hole.

Margitan, J. J.↗
NASA NTRS1987

Cloud temperatures from ammonia observations

In association with an ammonia survey of the southern Galaxy (Peters et al., 1986), a search was made for improved analytical formulas to expedite the data analysis. Semi-empirical formulas are presented which relate the kinetic temperature of a molecular cloud to the kinetic temperature used in full statistical equilibrium calculations. The formulas can be used in a simple way to improve the estimate of the kinetic temperature obtained from ammonia observations.

Kuiper, T. B. H.↗
NASA NTRS1987

Was the eclipse comet of 1893 a disconnected coronal transient?

The comet-like feature obsereved in the solar corona by the Lick Observatory eclipse expedition to Chile in 1893 bears an interesting resemblance to the disconnection coronal transient reported by Illing and Hundhausen. Reports of possibly-related limb activity are reviewed to see whether a pre-discovery observation of a relatively rare type of coronal mass ejection was mis-interpreted. The goal of this study is to learn more about the morphology of mass ejections by examining observations that extend down to the low corona of a disconnection event.

Cliver, E. W.↗