Tech Briefs

A Common-Mode Digital Holographic Microscope

This instrument has no moving parts and allows scientists to image in 3D and in real time. NASA’s Jet Propulsion Laboratory, Pasadena, California Digital holography is a fast-growing field in optics, recently spurred by the advent of large-format digital cameras and high-speed computers. This method provides a time-series of volumetric information about a sample, but the instrument itself has no moving parts. It does not compromise performance such as image quality and spatial resolution. However, these systems are typically implemented as optical interferometers with two separate beam paths: one is the reference beam and the other is the science beam. Interferometers are sensitive instruments that are subject to misalignment, and they will have significantly reduced performance in the presence of mechanical vibrations.

Posted in: Briefs, Imaging

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High Field Superconducting Magnets

Applications include MRI machines, mass spectrometers, and particle accelerators. Goddard Space Flight Center, Greenbelt, Maryland A modified coil winding machine for small-diameter wire being used to enable higher packing densities for the superconducting magnets. This superconducting magnet developed at NASA Goddard Space Flight Center comprises a superconducting wire wound in adjacent turns about a mandrel to form the superconducting magnet; a thermally conductive potting material configured to fill interstices between the adjacent turns; and a voltage limiting device disposed across each end of the superconducting wire, and is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet. The thermally conductive potting material and the superconducting wire provide a path for dissipation of heat.

Posted in: Briefs, Electronics & Computers

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Distributed Diagnostics and Prognostics

The distributed health management architecture is comprised of a network of smart sensor devices. Ames Research Center, Moffett Field, California NASA has developed a method that prevents total system failure during emergencies, allowing parts of the system to continue to function, and making overall system recovery faster. A heterogeneous set of system components monitored by a varied suite of sensors and a health monitoring framework has been developed with the power and flexibility to adapt to different diagnostic and prognostic needs. Current state-of-the-art monitoring and health management systems are mostly centralized in nature, where all the processing is reliant on a single processor. This requires information to be sent and processed in one location. With increases in the volume of sensor data as well as the need for associated processing, traditional centralized systems tend to be somewhat ungainly; in particular, when faced with multi-tasking of computationally heavy algorithms. The distributed architecture is more efficient, allows for considerable flexibility in number and location of sensors placed, scales up well, and is more robust to sensor or processor failure.

Posted in: Briefs, Electronics & Computers

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Lens-Coupled Dielectric Waveguides

Small, lightweight, low-power interconnect solution with improved reliability and reduced packaging complexity. NASA’s Jet Propulsion Laboratory, Pasadena, California NASA’s Jet Propulsion Laboratory has developed a low-loss dielectric waveguide that provides a simple, versatile, and flexible transmission medium. Dielectric waveguides — long, solid pieces of dielectric that confine electromagnetic waves — offer high bandwidth and low transmission loss compared to conventional metallic waveguides. Despite these advantages, practical use of these waveguides has been limited because a large fraction of signal power is lost at the state-of-the-art interconnects joining conventional metallic waveguides and dielectric waveguides. JPL’s interconnect solution uses lens coupling to reduce these losses by a factor of 10 or more, yielding a reliable, cost-effective alternative to conventional waveguides.

Posted in: Briefs, Electronics & Computers

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Sampling and Control Circuit Board for an Inertial Measurement Unit

John H. Glenn Research Center, Cleveland, Ohio Scientists at NASA’s Glenn Re - search Center have developed a circuit board that serves as a control and sampling interface to an inertial measurement unit (IMU). The circuit board provides sampling and communication abilities that allow the IMU to be sampled at precise intervals. The data is minimally processed onboard and returned to a separate processor for inclusion in an overall system. The circuit board allows the normal overhead associated with IMU data collection to be performed outside of the system processor, freeing up time to run intensive algorithms in parallel. This Glenn technology consists of the circuit schematic, board layout, and microcontroller firmware for the IMU sampling and control circuit board.

Posted in: Briefs, Electronics & Computers

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Efficient Radiation Shielding Through Direct Metal Laser Sintering

Goddard Space Flight Center, Greenbelt, Maryland Functional and parametric degradation of microcircuits due to total ionizing dose (TID) often poses serious obstacles to deployment of critical state-of-the-art (SOTA) technologies in NASA missions. Moreover, because device dielectrics in which such degradation occurs vary from one fabrication lot to the next, these effects must be reevaluated on a lot-by-lot basis. Often, the most effective mitigation against TID degradation is the addition of radiation shielding to the electronics box. Unfortunately, shielding materials can add significant amounts of mass to a system, particularly when vulnerable parts require shielding over 4π steradians. One method for reducing mass is to apply spot shielding located only on the critical components that require it. Reduced box- and/or spacecraft-level shielding will necessitate more complex spot shielding to protect the component from the omnidirectional radiation environment.

Posted in: Briefs, Electronics & Computers

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Polyimide Aerogels with Three-Dimensional Cross-Linked Structure

Applications for the strong, flexible material include thermal insulation and lightweight sandwich structures. John H. Glenn Research Center, Cleveland, Ohio NASA-developed polyimide aerogels are 500 times stronger than conventional silica aerogels. The innovative aerogels represent a revolutionary advance over fragile silica aerogels because they are highly flexible and foldable in thin film form. As a thin film, they can be used to insulate industrial pipelines, automotive shields, and temporary housing structures, and can be used within protective clothing such as firefighting jackets, space suits, and parkas. As a thicker part, they can be easily molded to a shape, or sanded and machined to provide insulation as well as mechanical support. No other aerogel possesses the compressive and tensile strength of the NASA innovation while still retaining its ability to be flexibly folded to contour to whatever shape is needed.

Posted in: Briefs, Materials

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