Tech Briefs

Systems and Services for Near-Real-Time Web Access to NPP Data

Software for processing and interpreting S-NPP observations and related data has become publicly available and more readily usable. Marshall Space Flight Center, Alabama The recently launched Suomi National Polar-orbiting Partnership (SNPP) satellite, operated by NASA and the National Oceanic and Atmospheric Administration(NOAA), is providing multispectral global observations over the next several years to support a broad array of research and applications. SNPP data products consist of a complex set of data and metadata files in highly specialized formats, and the U.S. government’s operational ground segment delivers these to users with delays of several hours to a few days.

Posted in: Information Sciences, Electronics & Computers, Data Acquisition, Briefs

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CCSDS Telemetry Decoder VHDL Core

Costly ground support equipment can be eliminated. Goddard Space Flight Center, Greenbelt, Maryland A flexible Telemetry Decoder Core (TDC) has been designed to decode Consultative Committee for Space Data Systems (CCSDS) encoded telemetry data. The TDC can be used to eliminate costly ground support equipment by placing the telemetry decoding functions in an inexpensive, commercially available field programmable gate array (FPGA) integrated circuit instead of special-purpose printed circuit boards. The TDC can also be used in the design of telemetry systems by enabling end-toend simulation of these systems’ upfront simulation before any hardware is built. The TDC was developed for the Global Precipitation Measurement (GPM) project and because of its success on that project, it will be used to verify telemetry on the Magnetospheric Multiscale (MMS) project.

Posted in: Electronics & Computers, Briefs

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Thermal Response of a High-Power Switch to Short Pulses

Simulations are used to calculate temperature changes that occur inside semiconductor switch modules, where measurement is not possible. Army Research Laboratory, Aberdeen Proving Ground, Maryland Semiconductor switch modules composed of Super Gate Turn-Off Thyristors (SGTOs) have been evaluated. The switches are intended to handle kiloamplevel currents and may dissipate peak powers measured in megawatts. Recent experiments measured the response of a switch module composed of eight SGTOs to single-short, high-current pulses. Simulations of those experiments were performed to calculate the temperature changes that occur inside the devices, where measurement is not possible. Worst-case operating conditions in which the switches handle several pulses within the space of 4 or 5 seconds (s) also were simulated. Modeling and simulation were performed with SolidWorks 3D modeling software and SolidWorks Simulation computational fluid dynamics software from Dassault Systèmes.

Posted in: Electronics & Computers, Briefs

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Solar Panel and System Design to Reduce Heating and Optimize Corridors for Lower-Risk Planetary Aerobraking

New approach features aggressive load reduction to reduce risk. Goddard Space Flight Center, Greenbelt, Maryland This innovation presents a spacecraft aerobraking approach that reduces heating and optimizes corridors, which reduces overall risk. This is accomplished by combining solar panel aspect ratio and edge features with simple spacecraft packaging optimization and integrated thermal-analysis techniques that also allow specifying a more benign temperature corridor.

Posted in: Manufacturing & Prototyping, Briefs

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Low-Cost, Very Large Diamond-Turned Metal Mirror

Reliable plating and diamond-turning technologies produce visible quality mirrors for applications such as semiconductor manufacturing. Marshall Space Flight Center, Alabama This innovation is a method for fabricating a low-cost, lightweight, large-aperture mirror by constructing only the mirror substrate by electroforming on a master form machined from plastic foam. Electroformed tubes of the same NiP alloy are installed in the foam mirror substrate master. Installing electroformed NiP tubes in the plastic mirror master before plating on the plastic foam mirror substrate allows the mirror faceplate and the back surface of the mirror to be plated onto the ends of the connecting tubes in the foam plastic. Removal of the foam after plating is complete results in a very stiff and lightweight mirror substrate made only of a single material. The low cost of the electroformed mirror substrate is made possible by very fast production of a master surface made of plastic foam that can be rapidly machined with modern, high-speed machining technology to very good mechanical tolerances in only a few hours.

Posted in: Manufacturing & Prototyping, Briefs

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Very-High-Load-Capacity Air Bearing Spindle for Large Diamond Turning Machines

Marshall Space Flight Center, Alabama Large-load-capacity oil hydrostatic bearings generate prohibitive amounts of heat in large sizes when run at speeds useful for diamond turning of optical components. The viscosity of air is more than three orders of magnitude less than the thinnest oil; therefore, the frictional heating of large-diameter air bearings is very small and very manageable. A formidable manufacturing problem with large air bearings is that the extremely low viscosity of air requires that the thickness of the bearing film is also very small. This very small bearing clearance of 5–8 micrometers means that the required accuracy of geometry and dimensions of air bearing components is extremely difficult to achieve.

Posted in: Manufacturing & Prototyping, Briefs

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Elevated-Temperature, Highly Emissive Coating for Energy Dissipation of Large Surfaces

This coating can be used in high-temperature rocket nozzles, control surfaces, industrial furnaces, and transfer lines. Marshall Space Flight Center, Alabama This coating demonstrates high emittance above 80% or better at broad wavelengths within the infrared spectrum. It has shown to have an extremely stable emittance at lower wavelengths within the infrared (IR) spectrum, where energy dissipation is critical at elevated temperatures. The coating has demonstrated increases in surface texturing, and ultimately an increase in emissivity when exposed to temperatures up to 2,050 °F (≈1,120 °C). It is also stable at continuous run, elevated temperatures, and shows no signs of spalling or erosion.

Posted in: Materials, Coatings & Adhesives, Briefs

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