Tech Briefs

Pressure Sensor Using Piezoelectric Bending Resonators

This technology applies to any application in which high-pressure measurement is required. NASA’s Jet Propulsion Laboratory, Pasadena, California A pressure sensor was developed based on a piezoelectric bending resonator. The resonator is covered and mechanically coupled with a sealed enclosure. The impedance spectrum of the resonator changes with the deformation of the enclosure induced by pressure or force applied to the enclosure. The changes in the impedance can be mapped to exchanges in the external environment, and the shifts in the resonance can be used to track the pressure.

Posted in: Briefs, Sensors

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Using a Ubiquitous Conductor to Power and Interrogate Wireless Passive Sensors and Construct a Sensor Network

Sensor nodes are used in health monitoring of aircraft and vehicles, building monitoring, human activity monitoring, and information collection for fire and disaster rescue. Langley Research Center, Hampton, Virginia Many methods have been developed for interrogation of wireless passive sensors. Surface acoustic wave (SAW) sensors and RF reflection sensors can receive and reflect electronic magnetic waves that are broadcast and received by the antennas. The interrogation distance can range from several meters to tens of meters. These previously developed technologies have limitations. The signal frequency is very high (usually at GHz level), which increases the difficulties in signal processing and interrogation system development, and the interrogation distance is limited by the power attenuation in the space. Longer interrogation distance requires higher-power-density electromagnetic (EM) waves in signal broadcasting, which increases the EMI hazard to environments.

Posted in: Briefs, Sensors

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Full-Field Inverse Finite Element Method for Deformed Shape- and Stress-Sensing of Plate and Shell Structures

Real-time reconstruction of full-field structural displacements helps provide feedback to the actuation and control systems of aerospace vehicles with morphed-wing architecture. Langley Research Center, Hampton, Virginia Structural health management systems that, by way of real-time monitoring, help mitigate accidents due to structural failures, will become integral technologies of the next-generation aerospace vehicles. Advanced sensor arrays and signal processing technologies are utilized to provide optimally distributed in-situ sensor information related to the states of strain, temperature, and aerodynamic pressure. To process the massive quantities of measured data, and to infer physically admissible structural behavior, requires robust and computationally efficient physics-based algorithms.

Posted in: Briefs, Sensors

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Pressure-Optimized Optical Breath Gas Analyzer for Portable Life Support Systems

This instrument could be used in trace gas sensor applications where rapid sampling in a compact package is required, such as in human-occupied closed volumes. Lyndon B. Johnson Space Center, Houston, Texas Optical detection of gaseous carbon dioxide, water vapor (humidity), and oxygen is desired in Portable Life Support Systems (PLSS) incorporating state-of-the-art CO2 scrubbing architectures. Earlier broadband detectors are nearing their end of life, and recent advances in laser diode technology make replacement of earlier technology compelling. The function of the infrared gas transducer used during extravehicular activity (EVA) in the current spacesuit is to measure and report the concentration of CO2 in the ventilation loop. The next-generation PLSS requires next-generation CO2 sensing technology with performance beyond that presently in use on the Shuttle/International Space Station extravehicular mobility unit (EMU). Accommodation within spacesuits demands that optical sensors meet stringent size, weight, and power requirements. A sensor is required that is compact, low power, low mass, has rapid sampling capability, can operate over a wide pressure range, and can recover from condensing conditions.

Posted in: Briefs, Sensors

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Lightweight Metal Rubber Textile Sensor for In-Situ Lunar Health Monitoring

This personnel status sensor can be used to measure, record, and communicate heart rate, electrocardiogram (ECG), and core body temperature information. Lyndon B. Johnson Space Center, Houston, Texas Extravehicular activities (EVAs) are dangerous to astronauts for a number of reasons, including high levels of physical exertion, potential for impacts by space debris particulates that could puncture the spacesuit and cause depressurization, Moon dust exposure that is abrasive and possibly biologically harmful, harsh thermal environments (extreme variation from –150 to >120 ºC when directly exposed to the Sun), and extreme low pressure (≈0 atm). These harsh environmental conditions inevitably lead to emotional pressure and stress, which directly impact physiological condition and potentially affect performance and safety. Because many EVA operations are time-consuming, astronauts may be extremely uncomfortable for several continuous hours.

Posted in: Briefs, Sensors

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Autonomous Leading-Edge Slat Device for Reduction of Aeroacoustic Noise Associated with Aircraft Wings

Langley Research Center, Hampton, Virginia Conventional transport aircraft wing design is driven mainly by cruise efficiency, i.e., adequate lift is generated at high speed for level flight with minimal drag. Conventional high-lift systems (leading edge slats and trailing edge flaps) were designed to augment lift and stall characteristics at the low speeds encountered during landing.

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StormGen Weather Editor

Ames Research Center, Moffett Field, California Experiments that take into account the impact of convective weather on airspace operations, future concepts, and flight deck tools require a source of weather data that is readily available, of predictable quality, and tailorable to experimental objectives. Real-world weather data is sparse, highly random, and disorganized. Weather is dynamic in that it can change rapidly over time, in size, shape, intensity, and location. Also, weather typically is experienced through displays tied to sensors such as weather radars; different systems in the cockpit and on the ground will have different update rates.

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