Tech Briefs

Cooling Test Samples With a Combined Convective and Conductive System to Rapidly Reach 77 K

This innovation enables rapid cooling to 77 K of James Webb Space Telescope shields, which enables hypervelocity impact testing with micro-particle spheres. Lyndon B. Johnson Space Center, Houston, Texas In this innovation, a team successfully developed and implemented a combined convective and conductive cooling system that permits rapid cooling. Using a spray system, liquid nitrogen (LN2) was injected into a test article enclosure located in the target tank that was evacuated to a lower pressure than the surrounding ambient pressure of the White Sands Test Facility (WSTF). According to the saturation curve for nitrogen, temperatures lower than 77 K can be achieved by using the evaporative process as long as the pressure remains above the triple point where nitrogen ice is formed.

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Guarded Two-Dimensional Flat Plate Insulation Test Calorimeter with Attach Points

Consistent test results are obtained in a cost-effective, safe, reliable, and practical manner. John F. Kennedy Space Center, Florida Insulation systems usually do not operate on their own; they must work together with a structural system that is designed to support the article being insulated. Typically this structure penetrates the insulation, degrading it in some manner, and gives a pathway for the conduction of unwanted heat. High-performance insulation systems that use reflective foils are highly anisotropic (the heat flows more easily in one direction than the others), so disturbing the temperature gradients through the material can cause much greater effects than are due to the disturbances alone.

Posted in: Articles, Briefs, TSP, Data Acquisition, Sensors

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Test, Calibration, and Training Target for a Microwave Sensor

NASA’s Jet Propulsion Laboratory, Pasadena, California Human subjects are unsuitable for objective performance testing of victim detection radar because their heart and respiration rates are not controllable or repeatable. There are limitations on human targets from a safety standpoint as well. It is difficult to relate the ground truth to the measured data for a human target without needing additional equipment that must be attached to the human subject. Artificial targets using pneumatics do not provide sufficient fidelity of the radar return for development of identification algorithms.

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Magnetic Thermometer for High-Resolution 10-mK Scale Thermometry

Device features improved sensitivity. Goddard Space Flight Center, Greenbelt, Maryland A thin-film magnetic thermometer with integrated, superconducting quantum interference device (SQUID) readout has been designed for fast, precision temperature measurements in the 10-mK range. The compact magnetic thermometer consists of a miniature DC SQUID susceptometer with a dilute paramagnetic alloy deposited in one of the two series-configured, gradiometric SQUID pickup loops that form the SQUID inductance. Directly sensing the magnetic signal with the SQUID eliminates coupling losses that occur by transformer-coupling the signal to a remotely located SQUID, usually operating at a higher temperature, and consequently, with a higher noise floor.

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High-Temperature Ultrasonic Probe for In-Service Health Monitoring of Steam Pipes

The probe monitors the height of water condensation in steam pipes through the wall of the pipe. NASA’s Jet Propulsion Laboratory, Pasadena, California This ultrasonic, pulse-echo probe can sustain as high as 250 °C, and uses a piezoelectric transducer to generate and receive the ultrasonic pulses. The transducer is made of a piezoelectric material with high Curie temperature, and the probe is configured such that it is operated as air-backed and, thus, has minimum losses of power.

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Low-Weight, Durable, Low-Cost Metal Rubber Sensor System for Ultra-Long-Duration Scientific Balloons

Sensors integrated onto load-bearing seams measure axial loads in the most extreme environmental conditions. Goddard Space Flight Center, Greenbelt, Maryland Large axial load forces and extreme temperature ranges are typical for scientific balloon missions. Therefore, a durable, flexible, and thermally stable sensor material is needed. In this innovation, sensors have been designed to be integrated onto the load-bearing seams and/or outer balloon mesh polyethylene surface of the pressurized balloon system to measure accurately and continually axial loads under extreme environmental conditions for extended intervals (i.e. more than 100 days).

Posted in: Articles, Briefs, TSP, Coatings & Adhesives, Metals, Sensors

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Low-Power Charged Particle Counter for Space Radiation Monitoring

John H. Glenn Research Center, Cleveland, Ohio A miniature, low-power, solid-state detector for ionizing radiation was developed for use in more locations, and requiring less space and lower power than current technology. An accepted way of counting high-energy charged particles common in space radiation is to detect the light produced when the particles strike a scintillator material.

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