Manufacturing & Prototyping

Process for Coating Substrates With Catalytic Materials

This process can remove volatile organic compounds from indoor air in planes, automobiles, homes, and industrial plants. Langley Research Center, Hampton, Virginia This invention relates to the process of coating substrates with one or more components to form a catalyst; specifically, the process of layering one or more catalytic components onto a honeycomb monolith to form a carbon monoxide oxidation that combines CO and O2 to form CO2, or alternatively, a volatile organic compound oxidation catalyst that combines the compound and O2 to form CO2 and H2O.

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Portable Friction Stir Welding Machine

The machine is capable of butt-welding aluminum 1,100 workpieces 1/8 in. (≈3 mm) thick. Marshall Space Flight Center, Alabama A preliminary design of a portable friction stir welding (FSW) machine for use in space has been developed. The in-space FSW machine takes the form of a handheld router tool that is historically used in woodworking applications. With the design of the in-space FSW machine, the FSW tool is directly connected to the motor shaft while the motor is mounted to a small frame that supports the tool. The frame has handlebars that allow the operator to grasp the welder and maneuver it along a desired weld path. The key enabler of the in-space FSW machine is an innovative FSW tool design. The FSW tool is a fixed shoulder-to-shoulder bobbin tool that self-aligns and adjusts to the workpiece. The self-aligning and adjusting FSW (SAA-FSW) tool floats freely in the vertical direction, thereby eliminating any external axial load on the machine or operator. The total weight of the in-space FSW machine is 73 lb (≈33 kg), and it only requires one operator. The machine is capable of butt-welding aluminum 1,100 workpieces 1/8 in. (≈3 mm) thick.

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Multimode, Fiber-Coupled, Tungsten Silicide, Superconducting Nanowire Single-Photon Detector Array

Amorphous WSi allows a much greater active area due to lower incidence of nanowire constrictions. NASA’s Jet Propulsion Laboratory, Pasadena, California The superconducting nanowire single-photon detector (SNSPD) arrays created in this innovation were fabricated using a WSi nanowire process. A gold mirror layer is deposited on an oxidized silicon wafer, and amorphous-state WSi is sputtered from a compound target at a thickness of 5 nm. The WSi nanowire is embedded at the center of a three-layer vertical optical cavity consisting of two silica layers and a titanium oxide anti-reflective coating. The layer thicknesses were chosen, on the basis of simulations and measured material parameters, to optimize efficiency at the target communication wavelength of 1,550 nm, and to minimize the polarization dependence of the detector response.

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Sidewall Passivation of GaN Avalanche Photodiodes via Atomic Layer Deposition

Atomic layer deposition is explored as a sidewall passivation method for mesa-isolated gallium nitride. NASA’s Jet Propulsion Laboratory, Pasadena, California The visible-blind detection of UV light has important applications in planetary imaging and spectroscopy, astronomy, communications, and defense-related imaging. Future instruments for imaging in the ultraviolet will require improvements in detector capabilities. An all-solid-state ultraviolet detector will enable substantial improvements in mass, volume, complexity, power, and robustness compared with conventional image-tube-based technologies. One new class of solid-state UV detectors includes those based on the gallium nitride (GaN) family of materials. The electronic passivation methods described here are one promising way to produce detectors with the required low dark current characteristics, and show a significant improvement over current state-of-the-art passivation methods. These methods will contribute to a next-generation solar-blind, solid-state UV detector for a wide range of space-based UV instruments.

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Design and Analysis of Metal-to-Composite Nozzle Extension Joints

A design concept and subcomponent are identified that mitigate the stress associated with the coefficient-of-thermal mismatch. Marshall Space Flight Center, Alabama Analysis, design, fabrication, and testing were performed to create a new joint design for potential use in attaching a domestically available carbon-carbon (C–C) nozzle extension to the turbine exhaust manifold of a J-2X engine. Various attachment methods were investigated for a C–C-to-metallic joint, including the use of higher-thermal-expansion ceramic matrix composites both mechanically attached and also integrally fabricated to the C–C nozzle extension. The goal was to determine the advantages and disadvantages of different material and joint systems in order to converge on a design for a domestic joint and nozzle extension design that resulted in all positive margins of safety.

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Modeling Laser Ablation and Plume Chemistry in a Boron Nitride Nanotube Production Rig

Langley Research Center, Hampton, Virginia The future of manned and unmanned spaceflight and exploration depends on economical access to space through multifunctional, lightweight materials. Boron nitride nanotube (BNNT) composites offer distinct advantages for enhanced survivability during long-term flights. A production technique has been developed to manufacture BNNTs that implements laser energy deposition on a boron sample in a pressurized test rig.

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Damage-Free Finishing of Silicon X-Ray Optics Using Magnetic Field-Assisted Finishing

Goddard Space Flight Center, Greenbelt, Maryland Thin, segmented mirrors have been fabricated from monocrystalline silicon blocks. The material is economically viable, and is virtually free of internal stress because of its nearly perfect crystalline structure. The mirror surfaces will first be accurately figured and finished on thick silicon blocks, then sliced off at the desired thickness by wire electro-discharge machining. A finishing process has been conceived in which existing mirror-finishing processes are adapted to be capable of quickly and accurately figuring and finishing damage-free, segmented, monocrystalline silicon mirrors in a cost-efficient manner.

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