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Reliability Testing of GORE® Protective Vents in LED Luminaires

Outdoor lighting systems are designed with sealed housings to protect against environmental contaminants. Atmospheric conditions such as temperature shifts and relative humidity present challenges to the reliability of outdoor luminaires. Changes in ambient temperatures can lead to significant pressure differentials. Over time, pressure on the enclosure seals can cause them to fail and allow contamination and/or water to breach the enclosure. This shortens the life of the luminaire by damaging the wiring, leads and other electronics of the power supply driver and the LEDs. The moisture also reduces light efficiency and can cause condensation to form on the lenses and reflectors.

Posted in: Electronics & Computers, White Papers

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Fourier Transform Spectrometer on Autonomous Self-Healing Hardware Platform

This liquid crystal waveguide-based platform provides self-healing for electronics in dangerous or hard-to-reach locations. NASA’s Jet Propulsion Laboratory, Pasadena, California The autonomous self-healing (eDNA) hardware platform is a reconfigurable field-programmable gate-array (FPGA)-type platform developed by Technical University of Denmark (patent: WO/2010/060923). It is capable of autonomously reconfiguring itself in case a fault is detected and, thusly, restoring functionality at a fault-free location on the chip.

Posted in: Electronics & Computers, Briefs, TSP

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Low-Temperature-Compatible Electronics for a Miniature Nuclear Magnetic Resonance Spectrometer

The electronics have been demonstrated to function down to 77 K. NASA’s Jet Propulsion Laboratory, Pasadena, California Missions to Titan are severely limited in available mass and power because spacecraft have to travel over a billion miles to get there, consuming large masses of propellants. Thus low-mass, low-power instruments are a high priority need for Titan missions. A miniature, liquid-phase, high-resolution, pulsed proton-NMR (1H-NMR) spectrometer was developed with low mass (1.5 kg), requiring low power, that can be operated cryogenically on the surface of Titan. This work focuses on new pulsed electronic circuits, optimized for a nuclear magnetic resonance (NMR) spectrometer for analysis of hydrocarbon liquids on Titan.

Posted in: Electronics & Computers, Briefs, TSP

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Ionospheric Delay Compensation Using a Scale Factor Based on an Altitude of a Receiver

Lyndon B. Johnson Space Center, Houston, Texas GPS receivers must compensate for the delay a GPS signal experiences as it passes through the ionosphere in order to accurately determine the position of the receiver. Receivers limited to terrestrial operation may utilize the Klobuchar parameters transmitted by the GPS satellites to model the ionosphere and remove much of this delay. However, as a GPS receiver passes through the ionosphere, such as in a spacecraft or low-Earth orbit space station, the Klobuchar model no longer adequately approximates the correction to be applied. Other models exist, particularly the IRI 2007 model created by NASA et al., but these are too computationally complex to be performed in real time by common hardware available for space implementations. Moreover, although the IRI model provides extensive insight into the historical characteristics of the ionosphere, it is purely predictive for times beyond the publication date of the model. Still other models exist that can be used during post-processing but are also not available in real time.

Posted in: Electronics & Computers, Briefs, TSP

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Microelectronic Repair Techniques for Wafer-Level Integration

Goddard Space Flight Center, Greenbelt, Maryland Wafer-level integration was employed to mount the microshutter array for the James Webb Space Telescope (JWST) and the detector-read-out hybrid for TIRS (Thermal Infrared Sensor). In the case of the JWST substrate, two conductors (polysilicon and aluminum) separated by a silicon oxide insulating layer were fabricated on a roughly 85-mm-square silicon wafer. The size of the substrate, the density and length of the conductive traces, and the requirement of zero shorts and zero opens on the finished device necessitated nearly impossible cleanroom requirements. Techniques were developed to repair the inevitable shorts and opens created during the wafer fabrication process. The wafers were repaired to zero shorts and zero opens without degradation of device performance.

Posted in: Electronics & Computers, Briefs

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Multi-Gigabit-Rate Radiation Hard Bus

Goddard Space Flight Center, Greenbelt, Maryland A concept was developed for a multi-gigabit-rate, radiation-hardened (RH) bus that would support open-system architecture and provide a cost-effective, high-speed interconnect. This concept is based on Advanced Science and Novel Technology Company’s SerDes system, which supports a variety of interfaces, and operates at frequencies from DC to more than 15 GHz. The design of the improved SerDes is based on the company’s proprietary library of RH cells and functional blocks using annular FETs (field-effect transistors) that are available in commercial CMOS (complementary metal-oxide-semiconductor) technologies. Bus architecture and preliminary SerDes circuit design have been accomplished during this phase. At the time of this reporting, the complete chip was to be designed and fabricated in the next phase.

Posted in: Electronics & Computers, Briefs

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Re:Vision: A New Paradigm for Mid-Lifecycle Design Changes

For decades, replacing key components during the mid-lifecycle design refresh was seen as simply too costly and burdensome. Changes had to wait until the next generation. Today, technology changes too fast to wait to add new capabilities. Fortunately, there are other options. With the right partners and suppliers involved, a mid-lifecycle component change can provide cost savings and greater performance capabilities. This white paper explores when and why a mid-lifecycle component change makes sense.

Posted in: Electronics & Computers, White Papers

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