Tech Briefs

Design of Double Layer Rectenna Array for Fault Isolation of Schottky Diode in Operation Beyond V-Band Frequencies

Langley Research Center, Hampton, Virginia Microwave power transmission using rectenna technology has attracted a strong interest in conjunction with wireless electric power delivery to infrastructure and subjects located at a remote place. A typical rectenna, which is a major component of the wireless power transmission technology, consists of an antenna, a Schottky diode, and low-pass filters for low-frequency electromagnetic wave isolation in the device. To obtain high efficiency, an electromagnetic wave is collected through a high-resonance antenna, and the AC mode of coupled wave energy is delivered to a Schottky diode that rectifies AC power into DC power. By connecting rectennas in series or parallel, or in mixed way — as well as enlarging the receiving area — the rectenna array can capture microwave energy into a desirable mode of high power.

Posted in: Briefs, Electronics & Computers

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Hierarchical Support for Nanocatalysts

Lyndon B. Johnson Space Center, Houston, Texas This work focused on enhancing catalyst activity and durability by developing a method to control size, dispersion, and exposure. Existing nanocatalysts are typically fabricated in bulk or powder form. There are monolithic catalysts, but they rely on meso-porous materials as supports. Bulk nanocatalysts suffer from a lack of complete exposure to reagents, counteracting the benefits of the nanoparticles. Catalysts upon meso-porous support have limited exposure due to diffusion distances through the porous support. This requires higher catalyst loading, and may lead to particle coalescence and deactivation.

Posted in: Briefs, Materials

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Control of Carbon Nanotube Density and Tower Height in an Array

Applications include high-density semiconductor chips, and heat dissipation and thermal conduction in personal computers, smartphones, and televisions. Ames Research Center, Moffett Field, California Use of arrays of carbon nanotubes (CNTs) as an intermediary for transport of electrical particles (e.g., electrons) and/or transport of thermal energy from one body to another has grown. For example, a CNT array may be used for dissipation of thermal energy or accumulated electrical charge associated with operation of an electronics device or system. However, the device or system may require use of different CNT array densities in various regions because of differing transport requirements.

Posted in: Briefs, Materials

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In-Situ Chemical Analysis of Material Surfaces

Composition by freezing uses laser ablation and laser ionization mass spectrometry for detection of chemical, pharmaceutical, biotech, and hazardous materials. NASA’s Jet Propulsion Laboratory, Pasadena, California In order to understand whether the ablation laser would cause chemical reactions within the trapped organic molecules during resonant laser ablation of water ice containing organic molecules, a two-layer approach was devised. The first layer consisted of D2O ice containing organics that are inactive for the laser wavelength used (2.94 microns), and shown not to ablate under these conditions. When an additional layer of H2O ice was deposited on top of the D2O layer, both H2O and D2O layers, and the organics embedded in the D2O layer, became ablated due to resonant excitation of the H2O ice layer that transferred energy to the D2O layer. This showed that the organic matter is not damaged.

Posted in: Briefs, Materials

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Ratcheting Threaded Tapered Collet for use in Planetary Sample Caching Systems

The desired sample tube preload can be tailored to specific applications, and allows each sample to be individually secured. NASA’s Jet Propulsion Laboratory, Pasadena, California Aridged retention interface is necessary to secure planetary sample tubes within a caching system for use in future sample return missions. The assumed retention interface requirements are as follows: the interface shall maintain sample integrity at large deceleration landing loads; the interface shall minimize weight and complexity; and any required actuation for sample tube retention shall be performed by an external source (such as a robotic end-effector).

Posted in: Briefs, Mechanical Components

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Planetary Ice Mining by Down-Hole Energy Injection

This lightweight technology operates in low gravity with energy efficiency. John F. Kennedy Space Center, Florida Ice has been discovered on Mars and is present in the permanently shadowed craters on the Moon and on many asteroids. The ice is usually buried beneath an overburden of regolith. Evidence indicates this overburden may be a meter deep in some locations for the Moon; for Mars, it varies with latitude and may be as deep as or deeper than two meters in many locations. To obtain this ice as a resource in usable quantities, existing technology will require that it be strip-mined.

Posted in: Briefs, Mechanical Components

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Laser Architecture and Atomic Filter for Daytime Measurements Using Spaceborne Sodium Lidar

Goddard Space Flight Center, Greenbelt, Maryland A satellite-borne sodium lidar will provide key measurements that elucidate the complex relation between the chemistry and dynamics of the Earth’s mesosphere, and thus provide a thorough understanding of the composition and dynamics of this region. The inclusion of a well-characterized mesosphere in global models is essential for weather and climate prediction in the lower atmosphere. It also will help to elucidate the complex vertical coupling processes through which atmospheric weather affects space weather. Furthermore, once the technique is developed, it can be used to study the composition of other planetary atmospheres, which is identified as a key point in the recent Planetary Decadal Survey.

Posted in: Briefs, Test & Measurement

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