Space Research Leads to Handheld X-Ray Device
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Models depicting the ambient atmosphere which can overtake the spacecraft vacuum shield are presented. The subject areas discussed are: possible changing effects on the wake shield environment; possible utilization of the induced environmental contamination monitor; present state of the knowledge of the parameters used to describe the intermolecular collisions; the possibility of using simple models to describe the wake shield environment; possible errors associated with using kinetic theory to calculate that part of the atmosphere overtaking the shield; and a general assessment of the Monte Carlo techniques used to calculate the shield environment.
The BASIC algorithmic language is described, and a guide is presented for the programmer using the language interpreter. The high-level algorithm BASIC is a problem-oriented programming language intended for solution of computational and engineering problems.
An ion mass spectrometer having a cylindrical E bar x B bar analyzer and either a cylindrical or spherical electrostatic analyzer is described. The instrument has two nested channels and a postacceleration between the electrostatic and E bar x B bar analyzers for wide ranges of energy and mass responses. It is noted that the dual-channel construction not only doubles the data acquisition rate but also permits a reversal of the electrostatic field orientation in the inner channel for lighter ions. The outer channel is then optimized for ions of medium to high mass numbers, resulting in increased mass resolution for such heavy ions. When combined with a cylindrical E bar x B bar analyzer, a 90-deg-deflection angle spherical electrostatic analyzer provides an extremely wide viewing angle. The angular distribution of ions can be derived from such geometry if a position-sensitive resistive anode or a detector array is used at the exit aperture. Details on the principles of operation, the instrument design, and calibration are presented.
The advantage of 32-GHz links, the estimated link performance, and developments in the fields of antennas, low noise preamplifiers, radiometry, and propagation studies are discussed. A description of ways to demonstrate 32-GHz link capability concludes the discussion.
Crystal growth experiments in reduced gravity environment and related ground-based research have contributed significantly to the establishment of a scientific basis for semiconductor growth from the melt. NASA-sponsored research has been instrumental in the introduction of heat pipes for heat and mass transfer control in crystal growth and in the development of magnetic field induced melt stabilization, approaches primarily responsible for recent advances in crystal growth technology.
This brochure presents a general discussion of the role of computers in aerospace research at NASA's Lewis Research Center (LeRC). Four particular areas of computer applications are addressed: computer modeling and simulation, computer assisted engineering, data acquisition and analysis, and computer controlled testing.
Considerations are presented of telescopes and spectrometers planned to be designed and made by the Abastumani Astrophysical Observatory of the Georgian SSR Academy of Science. The purpose of this topic is to clarify actual scientific problems which are to be solved by using telescopes. The experiments will begin in 1995.
Acknowledging the importance of human beings on a mission to Mars, the University of Puerto Rico studied both psychological and physiological aspects. Different conditions necessary for human health and well-being were considered. As a result, habitability criteria were developed. The criteria are as follows: personal identification; social interaction; unpredictable conditions; contact with nature; mental landscapes; privacy; equalitarian conditions; variety; functionality; sensory stimulation; music and environmental sound; stability and security; comfort; and sense of orientation.
Papers presented on long-term exposure to ionizing radiation, obtained from the Long Duration Exposure Facility, included radiation monitoring, radiation effects, and dosimetry. Mechanisms of biological systems, especially cells, under ionizing radiation and relative biological effectiveness were compared. The role of HZE particles as agents of mutation were reported from plant, animal, and in vitro models. Data on known and predicted effects of cosmic rays and other solar radiation on biological systems included differences related to Linear Energy Transfer and heavy ion particles.
The proceedings include sessions on extraterrestrial organic chemistry and the origins of life; life on Mars: past, present and future; planetary protection of Mars missions; chemical evolution on Titan; origins and early evolution of biological (a) energy transduction and membranes (b) information and catalysis; and carbon chemistry and isotopic fractionations in astrophysical environments.
It is evident from reports in the literature that there are many confounding factors that are capable of modulating radiation-induced non-targeted responses such as the bystander effect and the adaptive response. It has even been suggested that the observation of non-targeted responses may not be universally observable for differing radiation qualities. Dr. William Morgan made many contributions to the study of radiation induced non-targeted effects and it is indeed this area of research where we first began our collaboration more than a decade ago. In this presentation, I will discuss elements of this journey together with a particular emphasis on the role of LET in non-targeted effects.
It is evident from reports in the literature that there are many confounding factors that are capable of modulating radiation-induced non-targeted responses such as the bystander effect and the adaptive response. It has even been suggested that the observation of non-targeted responses may not be universally observable for differing radiation qualities. Dr. William Morgan made many contributions to the study of radiation induced non-targeted effects and it is indeed this area of research where we first began our collaboration more than a decade ago. In this presentation, I will discuss elements of this journey together with a particular emphasis on the role of LET in non-targeted effects.
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A number of research instruments are available at NASA's Marshall Space Flight Center (MSFC) to support ISS researchers and their investigations. These modern analytical tools yield valuable and sometimes new informative resulting from sample characterization. Instruments include modern scanning electron microscopes equipped with field emission guns providing analytical capabilities that include angstron-level image resolution of dry, wet and biological samples. These microscopes are also equipped with silicon drift X-ray detectors (SDD) for fast yet precise analytical mapping of phases, as well as electron back-scattered diffraction (EBSD) units to map grain orientations in crystalline alloys. Sample chambers admit large samples, provide variable pressures for wet samples, and quantitative analysis software to determine phase relations. Advances in solid-state electronics have also facilitated improvements for surface chemical analysis that are successfully employed to analyze metallic materials and alloys, ceramics, slags, and organic polymers. Another analytical capability at MSFC is a mganetic sector Secondary Ion Mass Spectroscopy (SIMS) that quantitatively determines and maps light elements such as hydrogen, lithium, and boron along with their isotopes, identifies and quantifies very low level impurities even at parts per billion (ppb) levels. Still other methods available at MSFC include X-ray photo-electron spectroscopy (XPS) that can determine oxidation states of elements as well as identify polymers and measure film thicknesses on coated materials, Scanning Auger electron spectroscopy (SAM) which combines surface sensitivity, spatial lateral resolution (approximately 20 nm), and depth profiling capabilities to describe elemental compositions in near surface regions and even the chemical state of analyzed atoms. Conventional Transmission Electron Microscope (TEM) for observing internal microstructures at very high magnifications and the Electron Probe Micro-analyzer (EPMA) for very precise microanalysis are available as needed by the researcher. Space Station researchers are invited to work with MSFC in analyzing their samples using these techniques.