GENERAL

Keith L. Bedingfield*, Richard D. Leach** and Margaret B. Alexander, Editor, Spacecraft System Failures and Anomalies Attributed to the Natural Space Environment, NASA RP-1390, Systems Analysis and Integration Laboratory, Science and Engineering Directorate. NASA Marshall Space Flight Center, AL 35812 and *Universities Space Research Association, **Computer Sciences Corporation, August 1996, pp. 54.

Keywords: natural space environment, environments, environmental effects, environmental impacts, spacecraft environments, space environments

Abstract: The natural space environment is characterized by many complex and subtle phenomena hostile to spacecraft. The effects of these phenomena impact spacecraft design, development, and operations. Space systems become increasingly susceptible to the space environment as use of composite materials and smaller, faster electronics increases. This trend makes an understanding of the natural space environment essential to accomplish overall mission objectives, especially in the current climate of better/cheaper/faster. This primer provides a brief overview of the natural space environment -- definition, related programmatic issues, and effects on various spacecraft subsystems. The primary focus, however, is to catalog, through representative case histories, spacecraft failures and anomalies attributed to the natural space environment. This primer is one in a series of NASA Reference Publications currently being developed by the Electromagnetics and Aerospace Environments Branch, Systems Analysis and Integration Laboratory, Marshall Space Flight Center (MSFC), National Aeronautics and Space Administration (NASA).

B.F. James, O.A. Norton, M.B. Alexander, B.J. Anderson and H.C. Euler, The Natural Space Environment: Effects on Spacecraft, NASA RP-1350, Electromagnetics and Environments Branch, Systems Analysis and Integration Laboratory, Science and Engineering Directorate NASA Marshall Space Flight Center, AL 35812, November 1994, pp. 29.

Keywords: natural space environment, environments, environmental effects, environmentalimpacts, spacecraft environments, space environments

Abstract: The effects of the natural space environments on spacecraft design, development, and operation are the topic of a series of NASA Reference Publications currently being developed by the Electromagnetics and Environment Branch, Systems Analysis and Integration Laboratory, Marshall Space Flight Center. This primer provides an overview of the natural space environments and their effect on spacecraft design, development, and operations, and also highlight some of the new developments in science and technology for each space environment. It is hoped that a better understanding of the space environment and its effect on spacecraft will enable program management to more effectively minimize program risks and costs, optimize design quality, and successfully achieve mission objectives.

B.J. Anderson, Editor, and R.E. Smith, Compiler, Natural Orbital Environment Definition Guidelines for Use in Aerospace Vehicle Development, NASA TM-4527 , Systems Analysis and Integration Laboratory, NASA Marshall Space Flight Center, AL 35812, June 1994, (N94-36175).

Abstract: This document provides definitions of the natural near-Earth space environment suitable for use in the initial development/design phase of any space vehicle. The natural environment includes the neutral atmosphere, plasma, charged particle radiation, electromagnetic radiation (EMR), meteoroids, orbital debris, magnetic field, physical and thermal constants, and gravitational field. Communications and other unmanned satellites operate in geosynchronous-Earth orbit (GEO); therefore, some data are given for GEO, but emphasis is on altitudes from 200 to 1,000 km (low-Earth orbit (LEO)). This document does not cover the induced environment or other effects resulting from presence of the space vehicle. Manmade factors are included as part of the ambient natural environment; i.e., orbital debris and radio frequency (RF) noise generated on Earth, because they are not caused by the presence of the space vehicle but form part of the ambient environment that the space vehicle experiences.

D.L. Johnson, Editor, Terrestrial Environment (Climatic) Criteria Guidelines for Use in Aerospace Vehicle Development, 1993 Revision, NASA TM-4511, Space Sciences Laboratory, NASA Marshall Space Flight Center, AL 35812, August 1993, (N94-14824).

Abstract: This document provides guidelines on terrestrial environment data specifically applicable in the development of design requirements/specifications for NASA aerospace vehicles and associated equipment development. The primary geographic areas encompassed are the John F. Kennedy Space Center, FL: Vandenberg AFB; Edwards AFB, CA; Michoud Assembly Facility, New Orleans, LA; John C. Stennis Space Center, MS; Lyndon B. Johnson Space Center, Houston, TX; and the White Sands Missile Range, NM. In addition, a section has been included to provide information on the general distribution of natural environmental extremes in the conterminous United States that may be needed to specify design criteria in the transportation of space vehicle subsystems and components. A summary of climatic extremes for worldwide operational needs is also included. Although not considered as a specific vehicle design criterion, a section on atmospheric attenuation has been added since sensors on certain Earth orbital experiment missions are influenced by the Earth's atmosphere. This document presents the latest available information on probable climatic extremes and supersedes information presented in TM- X-64589, TM X-64757, TM X-78118, and TM-82473. Information is included on atmospheric chemistry, seismic criteria, and on a mathematical model to predict atmospheric dispersion of aerospace engine exhaust cloud rise and growth. There is also a section on atmospheric cloud phenomena. The information in this report is recommended for use in the development of aerospace vehicle and associated equipment design and operational criteria, unless otherwise stated in contract work specifications. The environmental data in this report are primarily limited to information below 90 km.

C.G. Justus,*, W.R. Jeffries III,*, S.P. Yung,* and D.L. Johnson, The NASA/MSFC Global Reference Atmospheric Model-1995 Version (GRAM-95), NASA TM-4715, Systems Integration and Analysis Laboratory, Science and Engineering Directorate. NASA Marshall Space Flight Center, AL 35812 and *Computer Sciences Corporation, Huntsville, AL., August 1995, pp. 126.

Keywords: Global Reference Atmospheric Model, Orbital Altitude Atmosphere Model, Pressure, Temperature, Density, Winds, Atmospheric Perturbation Upper Atmosphere, Technical Description/Users Guide

Abstract: The latest version of the Global Reference Atmospheric Model (GRAM-95) is presented and discussed. GRAM-95 uses the new Global Upper Air Climatic Atlas (GUACA) CD-ROM data set, for 0- to 27-km altitudes. As with earlier versions, GRAM-95 provides complete geographical and altitude coverage for each month of the year. Individual years 1985 to 1991 and a period-of-record (1980 to 1991) can be simulated for the GUACA height range. GRAM-95 uses a specially developed data set, based on Middle Atmosphere Program (MAP) data, for the 20- to 120-km height range, and the NASA Marshall Engineering Thermosphere (MET) model for heights above 90 km. Fairing techniques assure a smooth transition in the overlap height ranges (20 to 27 km and 90 to 120 km). In addition to the traditional GRAM variables of pressure, density, temperature and wind components, GRAM-95 now includes water vapor and 11 other atmospheric constituents (O3, N2O, CO, CH4, CO2, N2, O2, O , A, He, and H). A new, variable-scale perturbation model provides both large-scale and small-scale deviations from mean values for the thermodynamic variables and horizontal and vertical wind components. The perturbation model includes new features that simulate intermittency (ñpatchinessî) in turbulence and small-scale perturbation fields. The density perturbations and density gradients (density shears) computed by the new model compare favorably in their statistical characteristics with observed density perturbations and density shears from 32 space shuttle reentry profiles. GRAM-95 provides considerable improvement in wind estimates from the new GUACA data set, compared to winds calculated from the geostrophic wind relations previously used in the 0- to 25-km height range. The GRAM-95 code has been put into a more modular form, easier to incorporate as subroutines in other programs (e.g., trajectory codes). A complete user's guide for running the program, plus sample input and output, is provided.

     
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