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NASA Launch Pads Protected Against Lightning-Induced Power Surges

Circuit protection components Littelfuse Chicago, IL 773-628-1000 www.littelfuse.com Circuit protection is an essential part of any electrical or electronic product or system design. As the complexity of the product or system grows, circuit protection design becomes increasingly crucial. As circuitry is increasingly miniaturized, it’s more important than ever to protect it from damaging power surges. For engineers whose work is critical to the safety of a NASA mission, protecting the lives of crewmembers depends to no small extent on protecting delicate digital circuitry from hazards like electrostatic discharges and lightning-induced surges.

Posted in: Application Briefs

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Micro-Accelerometers Monitor Equipment Health

MEMS-based accelerometers used on the International Space Station to control the microgravity environment are also used to monitor industrial machinery. Objects that orbit the Earth, such as the International Space Station (ISS), provide a unique environment called zero-g, or more correctly, microgravity. All objects in orbit are pulled by Earth’s gravity, but they achieve the lack of gravity when they move at just the right speed (in the case of the ISS, around 17,500 miles per hour) so that the curve of their fall matches the curve of the Earth. The result is a perpetual freefall, creating weightlessness.

Posted in: Articles, Spinoff

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Nanosensor/Cellphone Hybrid for Detecting Chemicals and Concentrations

Based on solid-state technology, the sensor requires no reagents and can be refreshed with an ultraviolet diode. Ames Research Center, Moffett Field, California Nanosensors have been developed for chemical detection using carbon nanotubes (CNTs). Unlike other chemical sensors, this solid-state approach requires no reagents and can be refreshed with a solid-state ultraviolet (UV) diode. The sensors possess high sensitivity (ppbv), fast response (≈2 s), high selectivity, low power (μW), and very small size (1 cm2 or less based on advanced miniaturization), and they are ideally suited for integration with wireless networks or cellphone type devices.

Posted in: Physical Sciences, Sensors, Briefs

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Coated or Doped Carbon Nanotube Network Sensors as Affected by Environmental Parameters

Applications include medical diagnostics, gas leak detection, and homeland security and defense. Ames Research Center, Moffett Field, California Chemical sensors have been developed over the past decades to detect gases and vapors at various concentration levels for deployment in a wide range of industrial applications. The detection usually centers on a change of a particular property or status of the sensing material, such as temperature, electrical, and optical characteristics. Other types of sensors include electrochemical cells, conducting polymer sensors, surface acoustic wave sensors, and catalytic bead sensors. Sensors based on nanotechnology promise to provide improved performance on all of these sensors compared to current micro and macro sensors.

Posted in: Physical Sciences, Sensors, Briefs

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Regenerable Internal CO Scrubber for Hydrogen Sensors

A guard electrode would protect the sensing electrode to maintain sensor sensitivity toward hydrogen. Lyndon B. Johnson Space Center, Houston, Texas Amperometric electrochemical sensors are commonly used for the detection of carbon monoxide (CO) and hydrogen (H2) in air. The electrochemistry of heterogeneous CO and H2 oxidations is similar enough that the sensors show significant cross-sensitivities between the two gases. Thus, in applications where H2 is being monitored in the presence of CO, amperometric hydrogen sensors will produce false positive responses due to the presence of CO. This error is further aggravated by the fact that the sensor’s response to CO is typically at least twice that for hydrogen on a volumetric basis. Furthermore, chronic CO exposure will poison or fatigue the H2 sensor electrodes and reduce the sensor sensitivity toward hydrogen.

Posted in: Physical Sciences, Sensors, Briefs

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Nanostructure Sensor Determines Presence and Concentration of a Target Molecule in Fluid

This sensing system works with resonant frequencies. Ames Research Center, Moffett Field, California Several methods are presently being developed to sense the presence of a target molecule in small or modest concentration in a fluid. However, estimation of the concentration of the target molecule is unavailable where the fluid is substantially motionless relative to the sensor, in part because the fluid in equilibrium will have substantially the same concentration everywhere.

Posted in: Physical Sciences, Sensors, Briefs

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Floating Ultrasonic Transducer Inspection System for Nondestructive Evaluation

Langley Research Center, Hampton, Virginia This floating ultrasonic transducer inspection system is based on a “momentary touching” scheme wherein the ultrasonic transducer is in contact with the structure being scanned for a relatively short time while performing the measurement. A vibrating element is a fundamental component, allowing the probe to lift up and down quickly over the surface being scanned. The measurement duty cycle would be long enough to acquire the data. Using this configuration reduces the coefficient of friction significantly by more than 95% based on the measurement duty cycle.

Posted in: Physical Sciences, Sensors, Briefs

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