1,011 research outputs found

    Voyager spacecraft phase B, task D. Volume 2 - System description. Book 5 - Final report

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    Voyager spacecraft design standards, and operational support and mission-dependent equipment requirement

    Thermal performance enhancement of packaging substrates with integrated vapor chamber

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    The first part of this research investigates the effects of copper structures, such as copper through-package-vias (TPVs), and copper traces in redistribution layer (RDL), on the thermal performance of glass interposers through numerical and experimental approaches. Numerical parametric study on 2.5D interposers shows that as more copper structures are incorporated in glass interposers, the performance of silicon and glass interposers becomes closer, showing 31% difference in thermal resistance, compared to 53% difference without any copper structures in both interposers. In the second part of this study, a thermal model of glass interposer mounted on the vapor chamber integrated PCB is developed using multi-scale modeling scheme. The comparison of thermal performance between silicon and glass interposers shows that integration of vapor chamber with PCB makes thermal performance of both interposers almost identical, overcoming the limitation posed by low thermal conductivity of glass. The third part of this thesis focuses on design, fabrication, and performance measurement of PCB integrated with vapor chamber. Copper micropillar wick structure is fabricated on PCB with electroplating process, and its wettability is enhanced by silica nanoparticle coating. Design of the wick for the vapor chamber is determined based on the capillary performance and permeability test results. Fabricated device with ultra-thin thickness (~800 µm) shows higher thermal performance than copper plated PCB with the same thickness. Finally, 3D computational fluid dynamics/heat transfer model of the vapor chamber is developed, and modeling result is compared with test result.Ph.D

    Retention and application of Skylab experiences to future programs

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    The problems encountered and special techniques and procedures developed on the Skylab program are described along with the experiences and practical benefits obtained for dissemination and use on future programs. Three major topics are discussed: electrical problems, mechanical problems, and special techniques. Special techniques and procedures are identified that were either developed or refined during the Skylab program. These techniques and procedures came from all manufacturing and test phases of the Skylab program and include both flight and GSE items from component level to sophisticated spaceflight systems

    Space station systems analysis study. Part 3: Documentation. Volume 7: SCB alternate EPS evaluation, task 10

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    Power levels up to 100 kWe average were baselined for the electrical power system of the space construction base, a long-duration manned facility capable of supporting manufacturing and large scale construction projects in space. Alternatives to the solar array battery systems discussed include: (1) solar concentrator/brayton; (2) solar concentrator/thermionic; (3) isotope/brayton; (4) nuclear/brayton; (5) nuclear thermoelectric; and (6) nuclear thermionic

    INVESTIGATION OF TECHNIQUES FOR REDUCING UNINTENTIONAL ELECTROMAGNETIC EMISSIONS FROM ELECTRONIC CIRCUITS AND SYSTEMS

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    This dissertation describes three independent studies related to techniques for reducing unintentional electromagnetic emissions from electronic circuits and systems. The topics covered are: low-inductance multi-layer ceramic capacitor for high frequency circuit board decoupling, the application of imbalance difference model to various circuit board and cable geometries, and balanced cable interface for reducing common-mode currents from power inverter. The first chapter discusses the importance and the meaning of the connection inductance associated with MLCCs and analyzes the effect of plate orientation in MLCCs. It demonstrates that vertically oriented plates have no more or less inductance than horizontally oriented plates when the overall dimensions of the plate stack are similar. Decoupling capacitance options at the various levels of a high-speed circuit is investigated to determine the range of frequencies that decoupling at each level is likely to be is effective. Innovative low-inductance capacitive-stem capacitor configurations are described and their connection impedance is compared to that of standard surface-mounted capacitors. The second chapter investigates the imbalance difference model that is a method for modeling how differential-mode signal currents are converted to common-mode noise currents. Various cable geometries to determine how well imbalance factor`s values of DM-to-CM conversion compare to full-wave calculations are explored. The imbalance difference model can be applied to cables with more than two conductors are demonstrated. The third chapter investigates the balanced cable interface for reducing common-mode currents from power inverter. The concept of a balancing network to reduce the common-mode currents on power inverter cables above 30 MHz is introduced. An experimental test set-up is used to demonstrate the effect of a balancing network on the common-mode current, differential-mode current and the common-mode rejection ratio on a balanced cable with an imbalanced termination. The balancing network is also evaluated using a 3-phase brushless DC motor driver to verify its effectiveness in a real application

    Advancing automation and robotics technology for the Space Station Freedom and for the US economy

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    The progress made by levels 1, 2, and 3 of the Office of Space Station in developing and applying advanced automation and robotics technology is described. Emphasis is placed upon the Space Station Freedom Program responses to specific recommendations made in the Advanced Technology Advisory Committee (ATAC) progress report 10, the flight telerobotic servicer, and the Advanced Development Program. Assessments are presented for these and other areas as they apply to the advancement of automation and robotics technology for the Space Station Freedom

    Voyager spacecraft. Volume III - Spacecraft implementation Final technical report, phase IA, task B

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    Voyager spacecraft implementation pla

    Voyager design study. volume vi- program plans

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    Voyager spacecraft design - landing module sterilization effects and requirements, long term space soak effects, high reliability requirements, and entry and operation on Mar

    Application of TOS/AMS to TDRS E and F

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    The development of the Transfer Orbit Stage (TOS) and the study of an Apogee and Maneuvering Stage (AMS) to be used in conjunction with the TOS are presented. A definition of the TOS/AMS configuration is provided along with a detailed design analysis including layout drawings, component definition, performance, sts and spacecraft interface definition, schedules, cost estimates, and specifications documents
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