Physical Sciences

Global Fire Detection Constellation

Small satellites could monitor and process images to track fires from space. NASA’s Jet Propulsion Laboratory, Pasadena, California Wildfires that start in backcountry areas sometimes burn for hours before being detected and reported. Satellites offer a vantage point from which infrared sensors can detect fires. Individual satellites in low Earth orbit (LEO) offer infrequent overpasses, making the delay from ignition to detection unacceptably long. Geostationary satellites offer a platform from which to maintain a round-the-clock vigil, but lack geographic precision, and cannot detect a rather small fire within a large pixel definitively above noise.

Posted in: Physical Sciences, Briefs, TSP

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Compact Solid-State Entangled Photon Source

John H. Glenn Research Center, Cleveland, Ohio In the fields of quantum information, quantum optics, quantum cryptography, and quantum communications, there is a need to generate entangled photon pairs. The entangled photon pairs are described by an inseparable wave equation such that if a measurement is performed on one photon, its twin’s photon state is completely determined. The problem up to now is that these sources of entangled photons require large, expensive, and power-intensive Ar-ion lasers to generate light in the UV to pump a nonlinear crystal to produce spontaneous parametric down conversion (SPDC). The SPDC process generates a pair of photons (the signal and the idler) whose momentum and energy sum up to equal the initial pump photon.

Posted in: Physical Sciences, Briefs, TSP

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Photogrammetric Recession Measurement

This method can be used to measure the recession of ablative materials in insulation coatings, ceramics and composites, arc-jet systems, and soil erosion. Ames Research Center, Moffett Field, California The testing of materials that ablate as a design function requires detailed time history of the ablation process. The rate at which the surface recedes during testing is a critically important measure of the performance of thermal protection system (TPS) materials like heat shields for aerospace vehicles. Photogrammetric recession measurement (PRM) meets these needs by recording the surface of the ablating model during heating in hyperthermal test facilities (arc-jets), using two high-resolution digital cameras capable of recording simultaneously. The cameras are calibrated to yield three-dimensional object space measurement for each stereo pair of images, producing surface recession data over the portion of the model for which both cameras share a view.

Posted in: Physical Sciences, Test & Measurement, Briefs

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Tissue-Equivalent Radiation Dosimeteron-a-Chip with Plastic Scintillation Material

This innovation uses solid-state technology to create a compact, lightweight, personal space radiation monitor. Lyndon B. Johnson Space Center, Houston, Texas The complexity of spaceflight design requires reliable, fault-tolerant equipment capable of providing real-time dosimetry during a mission, which is not feasible with existing thermoluminescent dosimeter (TLD) technology. Real-time monitoring is important for low-Earth-orbiting spacecraft and interplanetary spaceflight to alert the crew when solar particle events (SPE) increase the particle flux of the spacecraft environment. In this innovation, the personal dosimeter is comprised of a tissue-equivalent scintillator coupled to a solid-state photomultiplier.

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Measurement of Cryogenic Fluid Level with Laser Propagation and Surface Floor Reflection

The current float sensing system can be augmented with this new development. Stennis Space Center, Mississippi The risks associated with introducing new hardware and methods into an operational environment have in part prohibited cryogen level measurement technology from advancing. In prior art, measurements have been made with invasive probes immersed in the cryogenic fluid. Implementing this approach would require physical retrofitting, as well as requiring the measuring instrument to make contact with the harsh cryogen fluid environment. However, an externally mounted optical measurement system would mitigate these concerns. Therefore, an optical approach was developed that uses and augments existing validated technology in a manner that does not interfere with the current infrastructure.

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Video Acuity Measurement System

The smallest letters that can be automatically identified are used to rate the video system. Ames Research Center, Moffett Field, California There is a widely acknowledged need for metrics to quantify the performance of video systems. Existing metrics are either difficult to measure or are largely theoretical. They do not reflect the full range of effects to which video may be subject, or do not relate easily to video performance in real-world tasks. The empirical Video Acuity metric is simple to measure and relates directly to task performance. Video acuity is determined by the smallest letters that can be automatically identified using a video system. It is expressed most conveniently in letters per degree of visual angle.

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Heat-Flow Probe Design and Development

Applications include measuring heat flow on Earth, where optimal thermal isolation of heaters/temperature sensors is important. Marshall Space Flight Center, Alabama The lunar regolith exhibits extremely low conductivity. Penetrating the regolith presents problems if the geo-technical properties of the regolith are not well understood and accounted for.

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