Special Coverage

NASA Supercomputer Simulations Reveal 'Noisy' Aerodynamics
Robotic Gripper Cleans Up Space Debris
Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space

A High-Cross-Polarization-Isolation, Multi-Frequency Antenna for Cloud and Precipitation Research

Goddard Space Flight Center, Greenbelt, Maryland

The Global Precipitation Mission (GPM) has an immediate need for a matched-beam Ku-band/Ka-band antenna system that can be used as a component of a ground validation radar. Retrieval techniques based on both polarization and differential absorption at the two wavelengths can be used to provide additional insight into precipitation type and particle size distribution over a 10- to 40-km spatial domain. These measurements can then be compared with long range radar, such as the WSR-88D, and in situ sensors to provide a comprehensive dataset for evaluating and improving satellite-based precipitation estimates.

Posted in: Briefs, TSP, Physical Sciences, Antennas, Radar, Sensors and actuators, Antennas, Radar, Sensors and actuators

External Magnetic Field Reduction Technique for Advanced Stirling Radioisotope Generator

New generators can be configured for very low magnetic emissions so as not to interfere with sensitive instrumentation.

John H. Glenn Research Center, Cleveland, Ohio

Linear alternators coupled to Stirling power converters are promising candidates for high-efficiency heat-to-electricity power conversion in space. Presently, the external magnetic field emissions of such converters may exceed the allowed emission limits for use with certain sensitive scientific instrumentation. This invention, based on concepts of magnetic moment balancing, can reduce such field emissions sufficiently to enable use of the space power Stirling converters in sensitive instrumentation missions.

Posted in: Briefs, Physical Sciences, Emissions, Electric power

Advanced P-Band Spaceborne Radar System

A new imaging approach can overcome the fundamental limitations of conventional radar systems.

Goddard Space Flight Center, Greenbelt, Maryland

Low-cost, flexible spaceborne radar architectures are needed to provide critical data for Earth and science applications. An instrument concept was developed for an advanced spaceborne radar system that can measure terrestrial biomass (woody mass per unit area), ecosystem structure (height and density), and extent on a global scale. The PNTB band polarimetric radar architecture employs advanced techniques to increase the science value of the measurements while achieving it at a lower cost. The spaceborne radar concept leverages the existing airborne L-band digital beamforming synthetic aperture radar (DBSAR) and the new P-band digital beamforming (DBF) polarimetric and interferometric EcoSAR (ESTO IIP) architectures that employ DBF and reconfigurable hardware to provide advanced radar capabilities not possible with conventional radar instruments.

Posted in: Briefs, TSP, Physical Sciences, Architecture, Radar, Architecture, Radar, Test equipment and instrumentation

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: Briefs, TSP, Physical Sciences, Fire detection, Satellites

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: Briefs, TSP, Physical Sciences, Optics, Optics

Photogrammetric Recession Measurement

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: Briefs, Physical Sciences, Test & Measurement, Failure modes and effects analysis, Optics, Optics, Protective structures, Thermal testing

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

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.

Posted in: Briefs, Physical Sciences, Test & Measurement, Plastics, Test equipment and instrumentation, Spacecraft

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

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.

Posted in: Briefs, Physical Sciences, Test & Measurement, Optics, Optics, Test equipment and instrumentation

Video Acuity Measurement System

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.

Posted in: Briefs, Physical Sciences, Test & Measurement, Mathematical analysis, Imaging, Imaging and visualization, Imaging, Imaging and visualization

Heat-Flow Probe Design and Development

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.

Posted in: Briefs, Physical Sciences, Test & Measurement, Test equipment and instrumentation, Thermal testing

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