Electrical/Electronics

Time-Scaled Activity Diagram Simulator

NASA’s Jet Propulsion Laboratory, Pasadena, California The Time-Scaled Activity Diagram Simulator software simulates and animates time-tagged events as an overlay on activity and internal block diagrams in MagicDraw as a plugin application. “Events” are quite generic and include atomic actions, compound actions, signal and message exchanges, invocations, and more. Events are specified in a schedule in a text file, which is ingested by the plug-in application. Concurrent and synchronized execution specified in the event schedule is illustrated within and across diagrams. Events correspond to nodes and edges of hierarchical activity models and corresponding structural decomposition. This software can be used to visually communicate the execution and timeline of any collection of scheduled events, including business, software, and spacecraft processes and procedures, and is applicable to most if not all missions.

Posted in: Briefs

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General-Use Nodal Network Solver (GUNNS)

GUNNS is a flow system modeling software package that combines nodal analysis and the hydraulic-electric analogy to simulate fluid, electrical, and thermal systems. Lyndon B. Johnson Space Center, Houston, Texas Crewed space vehicle training has always required highfidelity models of vehicle systems. Many of these systems, particularly of the “flow” variety, benefit from modeling the system as a whole, rather than relying only on the interactions between individual components. In general, system properties (temperatures, voltages, flow rates, etc.) are modeled both internal to and between physical components (valves, batteries, etc.). Lacking knowledge of the system atlarge, integration of flows between individual components is extremely difficult without incurring model instability and errors. The same analogous problem applies among fluid, thermal, and electrical systems. Nodal analysis is a method commonly used in industry to avoid this problem by representing these systems as a simultaneous system of equations.

Posted in: Briefs, TSP

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Modularized SIR-to-NetCDF Conversion Command-Line Tool

NASA’s Jet Propulsion Laboratory, Pasadena, California This innovation reads in a proprietary formatted binary data format known as Scatterometer Image Reconstruction (SIR), and converts these data files to netCDF-classic format. This software is provided as a command-line tool for Linux/UNIX-based systems, and includes built-in regression testing and command line options. The software is configured to output the netCDF files using a metadata conformance to Attribute Convention for Dataset Discovery (ACDD) and Climate and Forecasting (CF) version 1.6. This software is initially tested and designed for SIR files created for datasets originating from QuikSCAT and SeaWinds on ADEOS-II.

Posted in: Briefs

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Fault Recovery for Multi-Phase Power Converters

This method has application in power converters for thin film deposition to prevent loss of expensive silicon wafer products. John H. Glenn Research Center, Cleveland, Ohio A fault recovery method for multiphase power converters enables delivery of reduced output power of as much as 66% of normal power in the event of a shorted power switch component. The need for redundant power converters in conventional multi-phase space power systems is reduced, if not eliminated. Fault recovery includes detecting a shorted power switch fault, providing short circuit current protection, providing isolation of the shorted power switch, and reconfiguring the remaining undamaged power switches.

Posted in: Briefs, TSP, Power Management

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Isolated Bidirectional DC Converters for Distributed Battery Energy Applications

This development is applicable to electric propulsion systems of vehicles. John H. Glenn Research Center, Cleveland, Ohio Power systems are the core heartbeat of any advanced vehicle. Reliability and flexibility of these systems are of the highest priority. This innovation is a highly efficient and modular isolated bidirectional DC converter for battery energy applications that has been translated into high-priority NASA power system applications, demonstrating transferability, robustness, and scalability.

Posted in: Briefs, TSP, Power Management

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Device Accommodating Volume Expansion and Contraction for Water-Ice Phase Change Material Heat Sinks

This innovation enables the use of water as a phase change material for thermal energy storage. Lyndon B. Johnson Space Center, Houston, Texas This invention accommodates the volume expansion and contraction of water ice as it freezes and thaws, thus enabling the use of water as a phase change material (PCM) for thermal energy storage. Due to the relatively large volume expansion of water upon freezing, and the relatively large bulk modulus of elasticity of ice, it is imperative to accommodate the volume expansion in order to prevent rupture of the containment vessel. In addition to accommodating the volume expansion associated with the phase change from liquid water to solid ice, this invention is usable at temperatures as low as –150 °C, thus enabling the ice to be super-cooled for additional sensible thermal storage capacity. Finally, this invention operates independent of gravity, enabling its use in space applications.

Posted in: Briefs, TSP, Power Management

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High-Power, Solid-State Power Amplifier System

Marshall Space Flight Center, Alabama The purpose of the invention was to increase the operational power levels of solid-state power amplifiers using state-ofthe- art power amplifier design and combining methodology. Using 1-kW RF modules and proper RF combining techniques, a system was built that generated 16 kW of RF power for use in electric plasma propulsion. The 1-kW units were fault-protected against excessive power, excessive current, and high VSWR, since the RF power devices are extremely sensitive to variations in their operating conditions.

Posted in: Briefs, Power Management

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