786 research outputs found
Entry guidance and entry autopilot (STS-1 baseline)
Preliminary entry guidance and autopilot software formulations, for use in the Mission Control Center (MCC) entry processor, are presented. The MCC requirements are met by a definition of coordinate systems, a list of parameter definitions for the software formulations, a description of the entry guidance detailed formulation requirements, a description of the detailed autopilot formualtion requirements, a description of the targeting routine, and a set of formulation flow charts
Shuttle program. MCC Level C formulation requirements: Entry guidance and entry autopilot
A set of preliminary entry guidance and autopilot software formulations is presented for use in the Mission Control Center (MCC) entry processor. These software formulations meet all level B requirements. Revision 2 incorporates the modifications required to functionally simulate optimal TAEM targeting capability (OTT). Implementation of this logic in the MCC must be coordinated with flight software OTT implementation and MCC TAEM guidance OTT. The entry guidance logic is based on the Orbiter avionics entry guidance software. This MCC requirements document contains a definition of coordinate systems, a list of parameter definitions for the software formulations, a description of the entry guidance detailed formulation requirements, a description of the detailed autopilot formulation requirements, a description of the targeting routine, and a set of formulation flow charts
Silicon Microleaks for Inlets of Mass Spectrometers
Microleaks for inlets of mass spectrometers used to analyze atmospheric gases can be fabricated in silicon wafers by means of photolithography, etching, and other techniques that are commonly used in the manufacture of integrated circuits and microelectromechanical systems. The microleaks serve to limit the flows of the gases into the mass-spectrometer vacuums to specified very small flow rates consistent with the capacities of the spectrometer vacuum pumps. There is a need to be able to precisely tailor the dimensions of each microleak so as to tailor its conductance to a precise low value. (As used here, "conductance" signifies the ratio between the rate of flow in the leak and the pressure drop from the upstream to the downstream end of the leak.) To date, microleaks have been made, variously, of crimped metal tubes, pulled glass tubes, or frits. Crimped-metal and pulled-glass-tube microleaks cannot readily be fabricated repeatably to precise dimensions and are susceptible to clogging with droplets or particles. Frits tend to be differentially chemically reactive with various gas constituents and, hence, to distort the gas mixtures to be analyzed. The present approach involving microfabrication in silicon largely overcomes the disadvantages of the prior approaches
Systems, methods, and apparatus of a low conductance silicon micro-leak for mass spectrometer inlet
Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels
Systems, Methods, and Apparatus of a Low Conductance Silicon Micro-Leak for Mass Spectrometer Inlet
Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels
Laboratory Simulations of the Titan Surface to Elucidate the Huygens Probe GCMS Observations
The Cassini/Huygens mission has vastly increased the information we have available to stndy Satnro's moon Titan. The complete mission has included an array of observational methods including remote sensing techniques, upper atmosphere in-situ saropling, and the descent of the Huygens probe directly through the atmosphere to the surface [1,2]. The instruments on the Huygens probe remain the ouly source of in-situ measurements at the surface of Titan, and work evaluating these measurements to create a pict.rre of the surface environment is ongoing. In particular, the Gas Chromatograph Mass Spectrometer (GCMS) experiment on Huygens found that although there were no heavy hydrocarbons detected in the lower atmosphere, a rich spectrum of mass peaks arose once the probe landed on the surface [3,4], However, to date it has not been possible to extract the identity and abundances of the many minor components of the spectra due to a lack of temperatnre- and instrumentappropriate data for the relevant species. We are performing laboratory stndies designed to elucidate the spectrum collected on Titan's surface, utilizing a cryogenic charober maintained at appropriate temperature and pressure conditions. The experiments will simulate the temperatnre rise experienced by the surface, which led to an enhanced signal of volatiles detected by the Huygens GCMS. The objective of this study is to exaroine the characteristics of various surface analogs as measured by the Huygens GCMS flight spare instrument, which is currently housed in our laboratory at NASA Goddard Space Flight Center (GSFC). This identification cannot be adequately accomplished through theoretical work alone since the thermodynamic properties of many species at these temperatnres (94 K, HASI measurement [5]) are not known
Tile Number and Space-Efficient Knot Mosaics
In this paper we introduce the concept of a space-efficient knot mosaic. That
is, we seek to determine how to create knot mosaics using the least number of
non-blank tiles necessary to depict the knot. This least number is called the
tile number of the knot. We determine strict bounds for the tile number of a
knot in terms of the mosaic number of the knot. In particular, if is the
tile number of a prime knot with mosaic number , then if is even and if is odd. We also
determine the tile number of several knots and provide space-efficient knot
mosaics for each of them.Comment: The original version of this article was split into two articles
during refereein
Calibration of the Neutral Mass Spectrometer for the Lunar Atmosphere and Dust Environment Explorer
Science objectives of the LADEE Mission are to (1) determine the composition, and time variability of the tenuous lunar atmosphere and (2) to characterize the dust environment and its variability. These studies will extend the in-situ characterization of the environment that were carried out decades ago with the Apollo missions and a variety of ground based studies. The focused LADEE measurements will enable a more complete understanding of dust and gas sources and sinks. Sources of gas include UV photo-stimulated desorption, sputtering by plasma and micrometeorites, as well as thermal release of species such as argon from the cold service or venting from the lunar interior. Sinks include recondensation on the surface and escape through a variety of mechanisms. The LADEE science payload consists of an Ultraviolet Spectrometer, a Neutral Mass Spectrometer, and a Dust Detector. The LADEE orbit will include multiple passes at or below 50 km altitude and will target repeated sampling at the sunrise terminator where exospheric density will be highest for some thermally released species. The science mission will be implemented in approximately three months to allow measurements to be made over a period of one or more lunations In addition to the science mission NASA will use this mission to demonstrate optical communication technology away from low Earth orbit
Mental Cage: A Qualitative Analysis of the Mental Game in the Sport of Mixed Martial Arts
Past research dealing with power sports has dealt mainly with the effects of participation in such sports as boxing and wrestling (Endresen & Olweus, 2005). Results have shown that participation in such sports has led to an increase and enhancement of violent and nonviolent antisocial behavior outside of sport (Endresen & Olweus, 2005; Bloom & Smith, 1996). The sport psychology literature has thus far failed to encompass the lived experience or possible themes that arise that stem from being a part of this culture. The purpose of this study was to examine the amateur Mixed Martial Arts athlete and their experience with mental skill usage in both training and competing. This study utilized existential phenomenological methodology and a humanistic framework. Data was collected from a purposeful sample of six amateur MMA fighters. Results were analyzed to uncover possible common themes experienced by the amateur MMA athlete
Uneven-aged management in the Missouri Ozarks: effects of site conditions, stand density, and prior populations on oak regeneration
While studies have shown the importance of site characteristics and overstory density on the success of white oak regeneration under uneven-aged management, few studies have analyzed the effects of these variables over time in the Missouri Ozarks. Here, we quantify the effects of site variables, stand density, and prior populations of reproduction on temporal patterns of white oak reproduction establishment and recruitment following decades of uneven-aged management. The results of this study indicate that while site characteristics, stand density, and prior populations are all important for white oak regeneration, this is not the case for every site characteristic or stage of regeneration. While xeric conditions often improve white oak regeneration, some xeric site characteristics, such as low available water capacity, reduce white oak regeneration. This study found that stand density reduction is also important for increasing future white oak recruitment; however, it was not important for increasing white oak seedling establishment. Further, under uneven-aged management stand density was not closely related to understory sunlight levels. Finally, prior populations of regeneration are vital to future recruitment, and it is necessary to have prior populations established many years in advance of desired recruitment.Includes bibliographical references
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