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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Spinoff from Space Astronomy

American Science and Engineering (AS&E) built NASA's first x-ray telescope, flown on OSO-4 (Orbiting Solar Observatory), and developed the x-ray detectors that operated flawlessly for four years aboard SAS-1 (Small Astronomy Satellite). The experience AS&E acquired in detecting and processing cosmic x-rays gave the company a broad technology base for commercial applications. Among the commercial products that stemmed from AS&E's space technology are: Micro Dose x-ray scanner for medical use; a digital radiography diagnosis, a system for nondestructive testing of manufactured products; a system of load management for electric utilities; and additional specialized instruments.

Source record↗
NASA NTRS1994

Proton-induced fragmentation of carbon at energies below 100 MeV

Radiation effects caused by single cosmic ray particles have been studied for many years in radiobiological experiments for different biological objects and biological end-points. Additionally, single event effects in microelectronic devices have gained large interest. There are two fundamental mechanisms by which a single particle can cause radiation effects. On the one hand, a cosmic ray ion with high linear energy transfer can deposit a high dose along its path. On the other hand, in a nuclear collision, a high dose can be deposited by short range particles emitted from the target nucleus. In low earth orbits a large contribution to target fragmentation events originates from trapped protons which are encountered in the South Atlantic Anomaly. These protons have energies up to a few hundred MeV. We study the fragmentation of C, O and Si nuclei - the target nuclei of biological material and microelectronic devices - in nuclear collisions. Our aim is to measure production cross sections, energy spectra, emission directions and charge correlations of the emitted fragments. The present knowledge concerning these data is rather poor. M. Alurralde et al. have calculated cross sections and average energies of fragments produced from Si using the cascade-evaporation model. D.M. Ngo et al. have used the semiempirical cross section formula of Silberberg and Tsao to calculate fragment yields and the statistical model of Goldhaber to describe the reaction kinematics. Cross sections used in these models have uncertainties within a factor of two. Our data will help to test and improve existing models especially for energies below 300 MeV/nucleon. Charge correlations of fragments emitted in the same interaction are of particular importance, since high doses can be deposited if more than one heavy fragment with a short range is produced.

Schmitz, M.↗
NASA NTRS1988

The Scintillating Optical Fiber Isotope Experiment

This paper describes the Scintillating Optical Fiber Isotope Experiment (SOFIE) which is being developed by Washington University and the University of New Hampshire to study the abundances of cosmic ray isotopes in the iron charge region. This detector system is a Cerenkov-Range-dE/dx experiment and utilizes range and trajectory detectors made of scintillating optical fibers, a fused silica Cerenkov counter, and plastic scintillator dE/dx counters to determine the charge and mass of cosmic ray nuclei. A brief description of the balloon flight instrument presently being developed will be given followed by initial results of an engineering model calibration at the LBL Bevalac heavy ion accelerator. In addition a brief discussion of the potential of scintillating fiber trajectory detectors for use in experiments requiring precise trajectory determination such as those being planned for the NASA Particle Astrophysics Magnet Facility (Astromag) program is presented.

Binns, W. Robert↗
NASA NTRS1995

Clementine Engineering Experiments Program.

Spacecraft must survive and operate reliably in the space environment for long periods of time. Radiation, temperature variations, spacecraft charging, surface contamination, and micrometeoroids/space debris all present environmental challenges to spacecraft missions. The environmental issues associated with these effects require in-situ space experiments to properly quantify the environment and its effects. To obtain data on specific microelectronic and sensor systems in the space environment, several engineering experiments were developed for the Clementine spacecraft and the Clementine lunar transfer booster or Interstage Adapter Satellite (ISAS). These platforms allowed testing of advanced spacecraft microelectronic and sensor devices in a lunar transfer orbit that intersects Earth's radiation belts and debris environment and in interplanetary space where direct exposure to solar flares, Galactic Cosmic Rays, and micrometeoroids was possible. A suite of experiments was developed by the Naval Research Laboratory (NRL), the Jet Propulsion Laboratory (JPL), NASA Langley Research Center (LaRC), the Aerospace Corporation, and NASA Goddard Space Flight Center (GSFC) to investigate in detail specific radiation and environmental reliability issues. This paper presents an introduction to the issues being investigated, the instruments provided for the mission, and the rationale for the engineering program.

Spacecraft↗
NASA NTRS1985

Nucleosynthesis in the terrestrial and solar atmospheres

Variations of Delta D, delta C-13, Delta C-14 and Delta O-18 with time were measured by a lot of experiments. Many abnormalities of isotope abundances in cosmic rays were found by balloons and satellites. It is suggested that these abnormalities are related to nuclearsynthesis in the terrestrial and solar atmospheres and are closely related to solar activities.

Yu, C.↗
NASA NTRS1985

Hadron cross sections at ultra high energies and unitarity bounds on diffraction dissociation

It was shown that if unitarity bounds on diffractive cross sections are valid at ultra high energies then diffractive dominance models which ascribe the increase in total hadron-hadron cross sections to diffractive processes only are ruled out. Calculations also show that cosmic ray cross sections derived from air shower experiments at ultra high energies clearly rule out models for hadron-hadron cross sections with nat.log ns energy dependence and favor those with nat.log n(2)s variation.

Yodh, G. B.↗
NASA NTRS1991

Study of geopotential error models used in orbit determination error analysis

The uncertainty in the geopotential model is currently one of the major error sources in the orbit determination of low-altitude Earth-orbiting spacecraft. The results of an investigation of different geopotential error models and modeling approaches currently used for operational orbit error analysis support at the Goddard Space Flight Center (GSFC) are presented, with emphasis placed on sequential orbit error analysis using a Kalman filtering algorithm. Several geopotential models, known as the Goddard Earth Models (GEMs), were developed and used at GSFC for orbit determination. The errors in the geopotential models arise from the truncation errors that result from the omission of higher order terms (omission errors) and the errors in the spherical harmonic coefficients themselves (commission errors). At GSFC, two error modeling approaches were operationally used to analyze the effects of geopotential uncertainties on the accuracy of spacecraft orbit determination - the lumped error modeling and uncorrelated error modeling. The lumped error modeling approach computes the orbit determination errors on the basis of either the calibrated standard deviations of a geopotential model's coefficients or the weighted difference between two independently derived geopotential models. The uncorrelated error modeling approach treats the errors in the individual spherical harmonic components as uncorrelated error sources and computes the aggregate effect using a combination of individual coefficient effects. This study assesses the reasonableness of the two error modeling approaches in terms of global error distribution characteristics and orbit error analysis results. Specifically, this study presents the global distribution of geopotential acceleration errors for several gravity error models and assesses the orbit determination errors resulting from these error models for three types of spacecraft - the Gamma Ray Observatory, the Ocean Topography Experiment, and the Cosmic Background Explorer.

Yee, C.↗
NASA NTRS2014

IXPE: The Imaging X-ray Polarimetry Explorer, Implementing a Dedicated Polarimetry Mission

Only a few experiments have conducted x-ray polarimetry of cosmic sources since Weisskopf et al confirmed the 19% polarization of the Crab Nebula with the Orbiting Solar Observatory (OSO-8) in the 70's center dot The challenge is to measure a faint polarized component against a background of non-polarized signal (as well as the other, typical background components) center dot Typically, for a few % minimum detectable polarization, 106 photons are required. center dot So, a dedicated mission is vital with instruments that are designed specifically to measure polarization (with minimal systematic effects) Over the proposed mission life (2- 3 years), IXPE will first survey representative samples of several categories of targets: magnetars, isolated pulsars, pulsar wind nebula and supernova remnants, microquasars, active galaxies etc. The survey results will guide detailed follow-up observations. Precise calibration of IXPE is vital to ensuring sensitivity goals are met. The detectors will be characterized in Italy, and then a full calibration of the complete instrument will be performed at MSFC's stray light facility. Polarized flux at different energies Heritage: X-ray Optics at MSFC polarimetry mission.

Ramsey, Brian↗
NASA NTRS2020

CALET Results after Three Years on the International Space Station

The CALET (CALorimetric Electron Telescope) space experiment, which is currently conducting direct cosmic-ray observations onboard the International Space Station (ISS), is an all-calorimetric instrument optimized for cosmic-ray electron measurements with capability to measure hadrons and gamma-rays. Since the start of observation in October 2015, smooth and continuous operations have taken place. In this paper, we will give a brief summary of the CALET observations ranging from charged cosmic rays, gamma-rays, to space weather, while focusing on the energy spectra of electrons and protons.

Y Asaoka↗
NASA NTRS1985

Solar neutrinos, solar flares, solar activity cycle and the proton decay

It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino data, but it appears that the neutrino flux which may be generated during the large solar cosmic ray events cannot in any way effect the solar neutrino data in Davis experiment. Only initial stage of mixing between the solar core and solar outer layers after the sunspot maximum in the solar activity cycle can explain the higher (run number 27 and 71) of solar neutrino data in Davis experiment. But solar flare induced atmospheric neutrino flux may have effect in the nucleon decay detector on the underground. The neutrino flux from solar cosmic rays may be a useful guide to understand the background of nucleon decay, magnetic monopole search, and the detection of neutrino flux in sea water experiment.

Raychaudhuri, P.↗
NASA NTRS1975

Solar cosmic ray 'square wave' of August 1972

Three Rice University suprathermal ion detector experiments (sides) were deployed on the lunar surface during the Apollo 12, 14, and 15 missions. During the exceptional period of solar activity in August 1972, penetrating particles were observed by all side detectors on the night side of the moon. The penetrating particles are tentatively identified as solar protons with energies (approximately 25 MeV or greater) that were able to penetrate the shielding of all detectors. Of particular interest is the occurrence on August 5 of a 'square wave' flux enhancement of 2-hour duration. Data from a variety of ground-based and space experiments are examined in relation to the square wave. Based on the results of this investigation a model relating the square wave to the flare plasma propagation is proposed. This model hypothesizes transport of energetic particles along a 'corridor' formed by the tangential discontinuity produced by the driver gas of a flare-induced shock wave. This model could explain other frequently observed delayed particle events.

Medrano, R. A.↗
NASA NTRS1975

Continuous observations of long-term variations in cosmic X-ray sources

Results are reported for the Charged Particle Measurements Experiment which was conducted on board IMP-7 to detect X-ray fluxes from the sun, the galactic center, Tau X-1, and Sco X-1 over a nine-month period. Autocorrelation analysis of the data indicates a probable 80-day periodicity in the flux from Sco X-1, a 110-day periodicity in the flux from the galactic center, no periodicities in the flux from Tau X-1, and a strong 27-day periodicity in the solar X-ray flux. A transient event detected within the cluster of sources constituting the galactic center is reported which lasted about two months and had a flux roughly equal to the regular flux from this area. It is noted that this was the only transient event detected in the whole area under continuous observation for the duration of the experiment.

Wende, C. D.↗
NASA NTRS1985

Elemental abundances of cosmic rays with Z 33 as measured on HEAO-3

The Heavy Nuclei Experiment on (HEAO-3) high energy astronomy observatory 3 uses a combination of ion chambers and a Cerenkov counter. During analysis, each particle is assigned two parameters, Z sub c and Z sub i, proportional to the square roots of the Cerenkov and mean ionization signals respectively. Because the ionization signal is double valued, a unique assignment of particle charge, Z, is not possible in general. Previous work was limited to particles of either high rigidity or low energy, for which a unique charge assignment was possible, although those subsets contain less than 50% of the total number of particles observed. The maximum likelihood technique was used to determine abundances for the complete data set from approx. 1.5 to approx. 80 GeV/amu.

Newport, B. J.↗
NASA NTRS1985

Arrival direction distribution of cosmic rays of energy 10 (18) eV

The Haverah Park air-shower experiment recorded over 8500 events with primary energy 10 to the 18th power eV between 1963 and 1983. An analysis of these events for anisotropies in celestial and galactic coordinates is reported. No very striking anisotropies are observed.

Eames, P. V.↗
NASA NTRS1985

On the possibility of the determining the average mass composition near 10 to the 14th power eV through the solar magnetic field

The discovery of primary ultrahigh energy (UHE) gamma-rays has spawned plans for a new generation of air shower experiments with unprecedented directional resolution. Such accuracy permits observation of a cosmic ray shadow due to the solar disc. Particle trajectory simulations through models of the large scale solar magnetic field were performed. The shadow is apparent above 10 to the 15th power eV for all cosmic ray charges /Z/ 26; at lower energies, trajectories close to the Sun are bent sufficiently for this shadow to be lost. The onset of the shadow is rigidity dependent, and occurs at an energy per nucleus of approx. Z x 10 to the 13th power eV. The possibility of determining the average mass composition near 10 to the 14th power eV from 1 year's observation at a mountain altitude array is investigated.

Lloyd-Evans, J.↗
NASA NTRS1980

The Pioneer Venus Orbiter Gamma Burst Detector

The Orbiter Gamma Burst Detector was designed to record the temporal and spectral characteristics of cosmic gamma-ray bursts. The primary mission of the experiment is the accurate determination of the directions to the sources of such bursts through a technique of triangulation as a member of a widely spaced array of similar instruments. The system consists of a pair of scintillation spectrometers sensitive in the range of energies between 100 and 2000 keV, together with logic and data storage to provide a capability for recording these events. Nineteen events which have been verified as cosmic gamma-ray bursts were recorded within the first year's operation.

Klebesadel, R. W.↗