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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4

An approach to studying the reliability of microgravity experiments

The identification of key factors that influence the non-success of experiments conducted under microgravity conditions will aid in the planning, design and implementation of future space shuttle experiments, as well as other microgravity experiments (i.e., experiments conducted on the Space Station). Similarly, knowledge of the experiments' reliability will assist in forecasting the success of forthcoming experiments. Since a relatively large number of Space Shuttle experiments have been conducted to date, a substantial pool of data exists for assessing the possible causes or factors which influence experiment non-successes. This report details the task being undertaken at NASA Lewis Research Center (LeRC) to measure the Space Shuttle experiments non-success trends and identify causes that significantly affect their performance. It addresses the activities associated with correlating experiment macro-factors with experiment non-successes. The development and implementation of a microgravity database to be used for tracking and correlating experiment non-success factors, as well as the criteria for measuring experiment success and non-success is also discussed.

Thaggard, Michael↗

An Approach to Studying the Reliability of Microgravity Experiments

The identification of key factors that influence the nonsuccess of experiments conducted under microgravity conditions will aid in the planning, design, and implementation of future space shuttle experiments, as well as other microgravity experiments (i.e., experiments conducted on the space station). Similarly, knowledge of the experiments' reliability will assist in forecasting the success of forthcoming experiments. Since a relatively large number of space shuttle experiments have been conducted to date, a substantial pool of data exists for assessing the possible causes or factors which influence experiment nonsuccesses. This report details the task being undertaken at NASA Lewis Research Center (LeRC) to measure the space shuttle experiments' nonsuccess trends and identify causes that significantly affect their performance. It addresses the activities associated with correlating experiment macro-factors with experiment nonsuccesses. The development and implementation of a microgravity database to be used for tracking and correlating experiment nonsuccess factors, as well as the criteria for measuring experiment success and nonsuccess, are also discussed.

Thaggard, Michael↗

Comprehensive Design Reliability Activities for Aerospace Propulsion Systems

This technical publication describes the methodology, model, software tool, input data, and analysis result that support aerospace design reliability studies. The focus of these activities is on propulsion systems mechanical design reliability. The goal of these activities is to support design from a reliability perspective. Paralleling performance analyses in schedule and method, this requires the proper use of metrics in a validated reliability model useful for design, sensitivity, and trade studies. Design reliability analysis in this view is one of several critical design functions. A design reliability method is detailed and two example analyses are provided-one qualitative and the other quantitative. The use of aerospace and commercial data sources for quantification is discussed and sources listed. A tool that was developed to support both types of analyses is presented. Finally, special topics discussed include the development of design criteria, issues of reliability quantification, quality control, and reliability verification.

Christenson, R. L.↗

Study of Two Digital Charge-Coupled Devices

Recent report describes reliability study of two charge-coupled-device (CCD) shift registers. Major objective of study was to establish methodology for selecting, testing, screening, derating and applying CCD's. Includes a discussion of CCD structures and operating principles. Characteristics of SCCD and BCCD types are compared.

Wilson, D. D.↗

Photovoltaic module and array reliability

Several statistical reliability studies have been conducted in areas of photovoltaic component design covering cell failure, interconnect fatigue, glass breakage and electrical insulation breakdown. This paper integrates the results from these various studies and draws general conclusions relative to optimal reliability features for future modules. The described analysis is based on designing for specified low levels of component failures and then controlling the degrading effects of the failures through the use of fault tolerant circuitry and module replacement. Means of selecting the cost-optimal level of component failures, circuit redundancy, and module replacement are described.

Ross, R. G., Jr.↗

Physics of Failure Analysis of Xilinx Flip Chip CCGA Packages: Effects of Mission Environments on Properties of LP2 Underfill and ATI Lid Adhesive Materials

The Xilinx Virtex 4QV and 5QV (V4 and V5) are next-generation field-programmable gate arrays (FPGAs) for space applications. However, there have been concerns within the space community regarding the non-hermeticity of V4/V5 packages; polymeric materials such as the underfill and lid adhesive will be directly exposed to the space environment. In this study, reliability concerns associated with the non-hermeticity of V4/V5 packages were investigated by studying properties and behavior of the underfill and the lid adhesvie materials used in V4/V5 packages.

Suh, Jong-ook↗

Physics of failure analysis of Xilinx Flip Chip CCGA packages: effects of mission environments on properties of LP2 underfill and ATI lid adhesive materials

The Xilinx Virtex 4QV and 5QV (V4 and V5) are next-generation field-programmable gate arrays (FPGAs) for space applications. However, there have been concerns within the space community regarding the non-hermeticity of V4/V5 packages; polymeric materials such as the underfill and lid adhesive will be directly exposed to the space environment. In this study, reliability concerns associated with the non-hermeticity of V4/V5 packages were investigated by studying properties and behavior of the underfill and the lid adhesvie materials used in V4/V5 packages.

Suh, Jong-ook↗