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Integrated and Automated Software Test Environment for JPL Software Defined Radio

NASA’s Jet Propulsion Laboratory, Pasadena, California Software has been developed that provides an integrated and automated test environment for the Space Telecommunications Radio System (STRS). This software package is Linux based and provides interactive and scripted control to test the JPL Software Defined Radio (SDR) implementing STRS hardware and software functionality. It also provides error checking and data logging capabilities for system diagnosis. This is a C programming language-based software that uses the host’s serial interfaces, a Ballard Technology, Inc. 1553 bus interface, and Star-Dundee SpaceWire-USB interface to communicate with the JPL SDR to issue test commands, receive telemetry, and transfer files.

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

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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.

Posted in: Manufacturing & Prototyping, Briefs

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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.

Posted in: Manufacturing & Prototyping, Briefs

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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.

Posted in: Manufacturing & Prototyping, Briefs

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Smart Crucibles and Heat Pipes

Molybdenum and molybdenum alloys are the leading candidates for making the new heat pipe modules. Marshall Space Flight Center, Alabama Near-net-shape vacuum plasma spray (VPS) forming techniques were developed to produce advanced components with internal features such as smart heat pipes and crucibles. The initial results demonstrated the ability to incorporate features such as channels and a porous layer within the wall of a smart crucible.

Posted in: Manufacturing & Prototyping, Briefs

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Technology-Independent RHBD Library Through Gate Array Approach

All gates in the library are based on one common cell. Goddard Space Flight Center, Greenbelt, Maryland As semiconductor technology nodes scale down, the limitation on polysilicon pitch makes it almost impossible to shrink libraries built for previous technologies. To design a library for a new technology, all of the cells have to basically start from scratch. Starting over for each technology node shrink is time-consuming and expensive. Further, obtaining space qualification for a technology node will require significant time and money. If a RHBD (radiation-hardened-by-design) library gates invention shares the same transistor structured as the SASIC (Structured Application-Specific Integrated Circuit), it will benefit from the existing qualification effort and high-performance advanced technology of the SASIC design flow.

Posted in: Electronics & Computers, Briefs

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Advanced Pulse Compression System and Testbed

Industrial applications include 3D machine vision systems that rely on radar for target identification and obstacle avoidance. Goddard Space Flight Center, Greenbelt, Maryland Detection of low-level water clouds from space is one of the outstanding challenges in radar remote sensing. Spaceborne remote sensing is the only means of assessing the distribution and variability of cloud cover on a global basis. Uncertainties in models of the Earth’s heating budget will persist until CloudSat and follow-on missions such as ACE (Advanced Composition Explorer), with enhanced radar capabilities, complete their missions. Detecting weak scatters at lower altitudes presents significant challenges. Millimeter-wave radars offer the only chance to measure these scatters from space. Unfortunately, the peak power available at Ka and W-band — desirable wavelengths for cloud remote sensing — does not provide adequate sensitivity at the resolution required. For many spaceborne radars, pulse compression techniques are used to overcome the limitations in peak power and take advantage of the average power available. But the backscatter from clouds, even at W-band, can be 7 to 8 orders of magnitude weaker than the surface backscatter. In order to use pulse compression techniques, peak range sidelobes need to be suppressed by upwards of 80 dB.

Posted in: Electronics & Computers, Briefs

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