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Thermal Cycle Qualification of Radiated Solar Arrays for 50 to 133 K Temperatures in Vacuum

A closed loop system needs no liquid helium. NASA’s Jet Propulsion Laboratory, Pasadena, California Solar arrays (radiated or non-radiated) and other technologies are candidate materials for projects in JPL. Some of the projects need to qualify these potential technologies to cryogenic extreme temperatures (from 133 to 50 K or lower). Those technologies need to survive for more than 120 thermal cycles in a thermal vacuum environment to meet three times mission life of the ECM project per JPL design principles. There is not any published thermal cycling qualification data for solar arrays in vacuum to those of cryogenic temperatures. Therefore, an experimental assessment study was undertaken on behalf of the JPL pre-project office for the proposed Europa Clipper mission.

Posted in: Briefs, TSP, Photonics

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Web-Based Search Service to Support Imaging Spectrometer Instrument Operations

An adaptive matched-filter approach compensates for the context and background characteristics of each scene. NASA’s Jet Propulsion Laboratory, Pasadena, California Imaging spectrometers yield rich and informative data products, but interpreting them demands time and expertise. There is a continual need for new algorithms and methods for rapid firstdraft analyses to assist analysts during instrument operations. Intelligent data analyses can summarize scenes to draft geologic maps, searching images to direct operator attention to key features. This validates data quality while facilitating rapid tactical decision-making to select follow-up targets. Ideally, these algorithms would operate in seconds, never grow bored, and be free from observation bias about the kinds of mineralogy that will be found.

Posted in: Briefs, TSP, Photonics

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Hermetic Phototube Housing

Goddard Space Flight Center, Greenbelt, Maryland This innovation is a hermetically sealed case or very small chamber. A photomultiplier tube (PMT) is mounted inside the chamber. The circuit board is also installed inside the chamber with appropriate feedthroughs for signals. An adapter/floating mount called the phototube to light pipe system mount (PLPSM) allows the hermetic PMT housing to attach to the light guide.

Posted in: Briefs, TSP, Photonics

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Design, Fabrication, and Test of WFIRST/AFTA GRISM Assembly

Goddard Space Flight Center, Greenbelt, Maryland This work originated with the Wide Field InfraRed Survey Telescope (WFIRST) slitless spectrometer design (GRISM assembly), which attempted to follow the Hubble Space Telescope (HST) method of employing a singleelement GRISM as a slitless spectroscope. However, WFIRST’s field of view (FOV) is ~100x of HST’s wide field camera, and the spectral resolution is ~5x higher with a relatively faster f/8 system. The design turned out to be extremely difficult using only one diffractive surface. Even with many freeform optical elements, and putting a grating on a toroid surface, the image performance was still not satisfactory.

Posted in: Briefs, TSP, Photonics

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Spinal Ultrasound Just-in-Time Training Tool

This software facilitates ultrasound imaging of the cervical and lumbar spine by crewmembers in-flight. Lyndon B. Johnson Space Center, Houston, Texas Back pain and injury are recognized risks that can affect the well-being and performance of crewmembers during missions, as well as their long-term health. Spine elongation is a documented effect of microgravity, back pain is a common occurrence in early flight, and the post-flight incidence of spinal injury is higher than the population average. These observations suggest that spinal unloading results in a transition to a new set point for the spine, and causes discomfort and an increased risk of injury.

Posted in: Briefs, TSP, Photonics

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Wide-Spectrum Organic Mass Spectrometer Using Far-Ultraviolet Ionization

Lyndon B. Johnson Space Center, Houston, Texas Two-step laser desorption/photoionization mass spectrometry (L2MS) represents a powerful tool for the organic analysis of astromaterials. The technique has high sensitivity and requires little to no sample preparation.

Posted in: Briefs, TSP, Photonics

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Megahertz-Rate Molecular Tagging Velocimetry

Langley Research Center, Hampton, Virginia In recent years, a large number of Lagrangian-based optical velocimetry techniques have been developed that are known, collectively, as either flow tagging velocimetry or molecular tagging velocimetry. In either case, the method is based on the use of an optical resonance to “tag” a pattern into a flow. After suitable time delay, the displacement of the initially tagged fluid volume is interrogated using optical imaging — either planar laser-induced fluorescence from a second resonant excitation, or, in the case of tracer molecules with sufficiently long radiative lifetime, spontaneous emission. The objective of this innovation is to allow velocity measurement in hypersonic flows at which detecting movement requires very high detection rates.

Posted in: Briefs, TSP, Optics

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