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Lunar Cold Trap Contamination by Landing Vehicles

Software and methods are developed to assess the magnitude and distribution of lunar surface contamination caused by the engine exhaust of a landing vehicle. John F. Kennedy Space Center, Florida The emerging interest in lunar mining poses a threat of contamination to pristine craters at the lunar poles, which act as cold traps for water, and may harbor other valuable minerals. Lunar Prospector type missions will be looking for volatile (molecular) compounds that may be masked by the exhaust gases from landing vehicle engines. The possible self-contamination of the landing site could negate the scientific value of the soil samples taken in the vicinity of the landing site. Self-contamination may also lead to false-positive readings of resources available on the lunar surface. This innovation addresses the software and methods needed to assess the magnitude and distribution of lunar surface contamination caused by the engine exhaust of landing vehicles on known or planned descent trajectories.

Posted in: Briefs, TSP

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Fabrication of Single-Mode, Distributed-Feedback, Interband Cascade Lasers

Applications exist in the oil and gas industry, automobile emissions monitors, breath analyzers, and fire detection equipment. NASA’s Jet Propulsion Laboratory, Pasadena, California Type-II interband cascade lasers (ICLs) based on the GaSb material system represent an enabling technology for laser absorption spectroscopy in the 3-to-5-μm wavelength range. Instruments operating in this spectral regime can precisely match strong absorption lines of several gas molecules of interest in atmospheric science and environmental monitoring, specifically methane, ethane, other alkanes, and inorganic gases. Compared with non-semiconductor-based laser technologies, ICLs can be made more compact and power efficient, ultimately leading to more portable, robust, and manufacturable spectroscopy instruments.

Posted in: Briefs, Lasers & Laser Systems, Optics, Photonics

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Developing Ceramic-Like Bulk Metallic Glass Gears

This technology has applications in gears, bearings, and gearboxes for automotive, spacecraft, and robotics. NASA’s Jet Propulsion Laboratory, Pasadena, California This invention describes systems and methods for implementing bulk metallic glass-based (BMG) macroscale gears with high wear resistance. This invention creates bulk metallic glasses (BMGs) with selected mechanical properties that are very similar to ceramics, such as high strength and resistance to wear, but without high melting temperatures. Ceramics are high-strength, hard materials that are typically used for their extremely high melting temperatures. Because of their extreme hardness, ceramics are optimal materials for making gears, due to their low wear loss. Unfortunately, ceramics suffer from low fracture toughness (typically <1 MPa·m1/2), and their high melting temperatures prevent them from being cast into net-shaped parts. Ceramic gears, for example, must be ground to a final shape at great expense.

Posted in: Briefs, Ceramics, Metals

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Mechanically Induced Nucleation Improves Crystalline Quality During Melt Growth of Semiconductors

Significantly lower supercooling results in the ideal growth condition of single crystal nucleation. Marshall Space Flight Center, Alabama For certain semiconductors with important applications, the existing bulk crystal growth technique from the melt usually results in poor-quality multi-crystalline ingots that cause the typically low yield of the commercial growth process. The low-quality, multi-grained crystal growth is mainly caused by the large supercool of the melt, which prohibits the ideal growth condition that a small, single-crystal nucleus forms at the very tip and grows into a large single crystal. For instance, semi-insulating cadmium zinc telluride (CdZnTe) crystal is a highly promising material for room-temperature x-ray and gamma ray detectors. However, the major hurdle in using the CdZnTe crystals is its cost. The ability to pack many data acquisition channels (hundreds) with the stopping power for high-energy radiation requires large single crystals of CdZnTe.

Posted in: Briefs

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Fabrication of a Nanopipette Array for Biosensing

Ames Research Center, Moffett Field, California Development of biosensors is an active field due to a wide range of applications in lab-on-a-chip, diagnostics of infectious diseases, cancer diagnostics, environment monitoring, biodetection, and others. One of the strategies used for selective identification of a target is to preselect a probe that has a unique affinity for the target, or can uniquely interact or hybridize with the target — a lock and key approach. In this approach, one then needs a platform to support the probe and a recognizing element that can recognize the said interaction between the probe and the target. Electrical readout biosensors have gained much attention because, in principle, they can be made more compact than optical technologies.

Posted in: Briefs

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Fabrication of a Nanopipette Array for Biosensing

Ames Research Center, Moffett Field, California Development of biosensors is an active field due to a wide range of applications in lab-on-a-chip, diagnostics of infectious diseases, cancer diagnostics, environment monitoring, biodetection, and others. One of the strategies used for selective identification of a target is to preselect a probe that has a unique affinity for the target, or can uniquely interact or hybridize with the target — a lock and key approach. In this approach, one then needs a platform to support the probe and a recognizing element that can recognize the said interaction between the probe and the target. Electrical readout biosensors have gained much attention because, in principle, they can be made more compact than optical technologies.

Posted in: Briefs, Sensors

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Variable-Sweep-Wing Aircraft Configuration

There are significant improvements in structural, aerodynamic, and energy efficiency. Ames Research Center, Moffett Field, California Efficient aircraft designs are increasingly desired in order to support the continued growth of the air transportation industry. Continued expansion of this vital mode of transportation is threatened due to concerns over ever-increasing emissions, noise, and the demand for fuel. Current airport runway, ramp, and terminal facilities are increasingly constrained by encroaching growth and neighborhood environmental issues. The challenges associated with ever-increasing demand for air travel will require the development of aircraft that can fly efficiently over wide speed ranges, minimize their environmental impacts, offer the potential for sizing and growth relative to market demand, and make efficient use of constrained airport and airspace resources.

Posted in: Articles, Briefs, Aviation, Energy Efficiency

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