Tech Briefs

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.

Posted in: Sensors, Articles, Briefs, TSP

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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: Materials, Coatings & Adhesives, Metals, Sensors, Articles, Briefs, TSP

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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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Ground-to-Space Laser Calibration System

This is a space-focused application located on the ground, which makes it easily accessible for maintenance and development. Langley Research Center, Hampton, Virginia The accuracy of spaceborne sensors measuring reflected solar radiance can be affected by multiple factors. First, instruments with complex optics are sensitive to polarization. The response of such instruments is characterized before launch; however, sensitivity to polarization can change on orbit significantly. None of the existing on-orbit sensors has the ability to monitor its sensitivity to polarization on orbit. Another factor is the degradation of optics, particularly in blue wavelength range below 500 nm. Currently, there is no reliable method to access spectral changes in the optics of instruments on orbit. The third factor contributing to changes in on-orbit calibration is the instrument response to stray light. The prior method of correcting radiometric measurement for polarization effects was based on vicarious calibration to the SeaWIFS instrument, which was designed not to be sensitive to polarization.

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PATTERNS: Panoptic Aspect Time Triggered Ethernet Robust Network Scheduler, Version 1.0

Lyndon B. Johnson Space Center, Houston, Texas The PATTERNS scheduling tool was created to test the multi-plane concept of a Time Triggered Ethernet (TTE) network. The TTE network interface cards used in the Orion vehicle contain three physical network ports, referred to as planes. Each plane exists to serve as a redundant communication channel for each link in the network. The scheduler used prior to PATTERNS was the vendorprovided demonstration tool, TTE-demo-scheduler, which was unable to schedule Ethernet traffic in a manner that would allow the plane-specific and plane-independent tests required to be performed.

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An Earth-Observing, Frequency-Agile Radar Receiver for RFI Mitigation

Applications include automotive collision-avoidance radar, cellular phone networks, and radar surveillance sensors for unmanned vehicles. NASA’s Jet Propulsion Laboratory, Pasadena, California The Soil Moisture Active Passive (SMAP) mission will have the first L-band radar/radiometer sensor suite dedicated to global measurements of soil moisture. For the radar sensor, the requirements for achieving high backscatter measurement accuracy from low-Earth orbit present a unique design challenge in the presence of terrestrial radio frequency interference (RFI). The SMAP radar shares the same 1,215 to 1,300 MHz spectrum used by high-power ground-based transmitters like air-route and defense surveillance radars, which can generate strong interference in a conventional fixed-frequency spaceborne radar. The noisy ground environment motivated the development of a frequency-hopping (self-tuning) feature in the radar design. As the SMAP spacecraft orbits across various regions of the Earth, the radar continually adjusts its RF operating frequency to quieter areas of the spectrum for improved fidelity in soil-moisture science data observations.

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