84 research outputs found

    Improving the system capacity of broadband services using multiple high-altitude platforms

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    A method of significantly improving the capacity of high-altitude platform (HAP) communications networks operating in the millimeter-wave bands is presented. It is shown how constellations of HAPs can share a common frequency allocation by exploiting the directionality of the user antenna. The system capacity of such constellations is critically affected by the minimum angular separation of the HAPs and the sidelobe level of the user antenna. For typical antenna beamwidths of approximately 5/spl deg/ an inter-HAP spacing of 4 km is sufficient to deliver optimum performance. The aggregate bandwidth efficiency is evaluated, both theoretically using the Shannon equation, and using practical modulation and coding schemes, for multiple HAP configurations delivering either single or multiple cells. For the user antenna beamwidths used, it is shown that capacity increases are commensurate with the increase in the number of platforms, up to 10 HAPs. For increases beyond this the choice of constellation strategy becomes increasingly important

    Research and Technology Objectives and Plans Summary (RTOPS)

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    A compilation of summary portions of each of the Research and Technology Objectives and Plans (RTOPS) used for management review and control of research currently in progress throughout NASA is presented. Subject, technical monitors, responsible NASA organization, and RTOP number indexes are included

    User benefits and funding strategies

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    The justification, economic and technological benefits of NASA Space Programs (aside from pure scientific objectives), in improving the quality of life in the United States is discussed and outlined. Specifically, a three-step, systematic method is described for selecting relevant and highly beneficial payloads and instruments for the Interim Upper Stage (IUS) that will be used with the space shuttle until the space tug becomes available. Viable Government and private industry cost-sharing strategies which would maximize the number of IUS payloads, and the benefits obtainable under a limited NASA budget were also determined. Charts are shown which list the payload instruments, and their relevance in contributing to such areas as earth resources management, agriculture, weather forecasting, and many others

    Research and Technology Objectives and Plans Summary (RTOPS)

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    A compilation of the summary portions of each of the Research and Technology Objectives and Plans (RTOPS) used for management review and control research currently in progress throughout NASA is presented. Indexes include: subject, technical monitor, responsible NASA organization, and RTOP number

    Research and Technology Objectives and Plans Summary (RTOPS)

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    This publication represents the NASA research and technology program for FY 1985. It is a compilation of the Summary portions of each of the RTOPs (Research and Technology Objectives and Plans) used for management review and control of research currently in progress throughout NASA. The RTOP summary is designed to facilitate communication and coordination among concerned technical personnel in government, in industry, and in universities. The first section containing citations and abstracts of the RTOPs is followed by four indexes: Subject, Technical Monitor, Responsible NASA Organization, and RTOP number

    RV ALKOR Fahrtbericht / Cruise Report AL533 - Mutual Field Trials of the Manned Submersible JAGO and the Hover-AUVs ANTON and LUISE off the Aeolian Islands, Mediterranean Sea, Catania (Italy) – La Seyne-sur-mer (France) 05.02. – 18.02.2020

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    The tight program of scientific research cruises usually does not leave enough time for thorough tests of new research equipment and their system components, nor for extensive pilot and handling training. For this reason, ship time was requested for sea trials of two types of autonomous (not tethered) underwater vehicles owned by GEOMAR, the manned 400-meter submersible JAGO and the Hover-AUVs ANTON and LUISE, type Girona500. The aim was to test several technical and operational aspects with both vehicles at locations with differently structured terrain (from flat ground to steep rocky slopes) and to water depths of up to 500 meters. The Aeolian Islands in the Tyrrhenian Sea north of Sicily were chosen as test area. The volcanic islands offer sheltered sea conditions at their leeway, and bottom currents are usually weak or absent. Rocky and steep slopes are located in short distances to areas with flat underwater topography, providing ideal test conditions

    Aeronautics and space report of the President, 1982 activities

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    Achievements of the space program are summerized in the area of communication, Earth resources, environment, space sciences, transportation, aeronautics, and space energy. Space program activities of the various deprtments and agencies of the Federal Government are discussed in relation to the agencies' goals and policies. Records of U.S. and world spacecraft launchings, successful U.S. launches for 1982, U.S. launched applications and scientific satellites and space probes since 1975, U.S. and Soviet manned spaceflights since 1961, data on U.S. space launch vehicles, and budget summaries are provided. The national space policy and the aeronautical research and technology policy statements are included
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