Tech Briefs

A comprehensive library of technical briefs from engineering experts at NASA and major government, university, and commercial laboratories covering all aspects of innovations in electronics, software, photonics, imaging, motion control, automation, sensors, test, materials, manufacturing, mechanical, and mechatronics.

Briefs : Manufacturing & Prototyping
Radiation-Shielding Polymer/Soil Composites

It has been proposed to fabricate polymer/soil composites primarily from extraterrestrial resources, using relatively lowenergy processes, with the original intended application being that habitat structures constructed from such composites would have sufficient structural integrity and also provide...

Briefs : Physical Sciences
Statistical Model of Evaporating Multicomponent Fuel Drops

An improved statistical model has been developed to describe the chemical composition of an evaporating multicomponent- liquid drop and of the mixture of gases surrounding the drop. The model is intended for use in computational simulations of the evaporation and combustion of sprayed...

Briefs : Physical Sciences
Electrochemical Disposal of Hydrazines in Water

An electrochemical method of disposal of hydrazines dissolved in water has been devised. The method is applicable to hydrazine (N2H4), to monomethyl hydrazine [also denoted by MMH or by its chemical formula, (CH3)HNNH2], and to unsymmetrical dimethyl...

Briefs : Physical Sciences
Resistively Heated SiC Nozzle for Generating Molecular Beams

An improved nozzle has been developed to replace nozzles used previously in an apparatus that generates a substantially unidirectional beam of molecules passing through a vacuum at speeds of several kilometers per second. The need to replace the previous nozzles arose from a complex...

Briefs : Information Technology
Modeling Evaporation of Drops of Different Kerosenes

A mathematical model describes the evaporation of drops of a hydrocarbon liquid composed of as many as hundreds of chemical species. The model is intended especially for application to any of several types of kerosenes commonly used as fuels. Like evaporating- multicomponent- fuel-drop models...

Briefs : Information Technology
A Robustly Stabilizing Model Predictive Control Algorithm

A model predictive control (MPC) algorithm that differs from prior MPC algorithms has been developed for controlling an uncertain nonlinear system. This algorithm guarantees the resolvability of an associated finite-horizon optimal-control problem in a recedinghorizon implementation....

Briefs : Mechanical & Fluid Systems
Development of Vapor-Phase Catalytic Ammonia Removal System

A report describes recent accomplishments of a continuing effort to develop the vapor-phase catalytic ammonia removal (VPCAR) process for recycling wastewater for consumption by humans aboard a spacecraft in transit to Mars. The VPCAR process is implemented by a system of highly...

Briefs : Mechanical & Fluid Systems
Several Developments in Space Tethers

Five reports address different aspects of development of tethers to be deployed from spacecraft in orbit around the Earth. The first report discusses proposed optoelectronic tracking of retroreflective objects located at intervals or of retroreflective coats along the entire length of a tether to measure...

Briefs : Mechanical & Fluid Systems
Design Concept for a Nuclear Reactor-Powered Mars Rover

A report presents a design concept for an instrumented robotic vehicle (rover) to be used on a future mission of exploration of the planet Mars. The design incorporates a nuclear fission power system to provide long range, long life, and high power capabilities unachievable through the use...

Briefs : Mechanical & Fluid Systems
Formation-Initialization Algorithm for N Spacecraft

A paper presents an algorithm to initialize a formation of N distributed spacecraft in deep space. Such formations will enable variable-baseline interferometers in future NASA missions designed to study the structure and origin of the universe. The algorithm described in the paper reflects some...

Briefs : Physical Sciences
DNSs of Multicomponent Gaseous and Drop-Laden Mixing Layers Achieving Transition to Turbulence

A paper describes direct numerical simulations (DNSs) of three-dimensional mixing-layer flows undergoing transition to turbulence; the mixing layers may or may not be laden with evaporating liquid drops. In contrast to most studies in this field, the...

Briefs : Electronics & Computers
Noise-Canceling Helmet Audio System

A prototype helmet audio system has been developed to improve voice communication for the wearer in a noisy environment. The system was originally intended to be used in a space suit, wherein noise generated by airflow of the spacesuit life-support system can make it difficult for remote listeners to...

Briefs : Software
Program Analyzes Spacecraft/Ground Radio Links

A versatile computer program analyzes the link-design control table necessary for designing the telecommunication subsystem of a spacecraft in orbit around the Earth or on a deep-space mission. The program helps to calculate all the important parameter values for spacecraft-to-ground telemetry links...

Briefs : Mechanical & Fluid Systems
Six-Message Electromechanical Display System

A proposed electromechanical display system would be capable of presenting as many as six distinct messages. This system would be a more capable and more complex successor to the proposed system reported in "Four-Message Electromechanical Display System" (MFS-31368), NASA Tech Briefs, Vol. 24, No. 4...

Briefs : Electronics & Computers
Two-Way Communication Using RFID Equipment and Techniques

Equipment and techniques used in radio-frequency identification (RFID) would be extended, according to a proposal, to enable short-range, two-way communication between electronic products and host computers. In one example of a typical contemplated application, the purpose of the...

Briefs : Physical Sciences
Compact Packaging of Photonic Millimeter-Wave Receiver

A carrier structure made from a single silicon substrate is the basis of a compact, lightweight, relatively inexpensive package that holds the main optical/electronic coupling components of a photonic millimeter- wave receiver based on a lithium niobate resonator disk. The design of the...

Briefs : Manufacturing & Prototyping
Fabrication of Submillimeter Axisymmetric Optical Components

It is now possible to fashion transparent crystalline materials into axisymmetric optical components having diameters ranging from hundreds down to tens of micrometers, whereas previously, the smallest attainable diameter was 500 m. A major step in the fabrication process that makes...

Photonics Tech Briefs : Photonics/Optics
Mapping Nearby Terrain in 3D by Use of a Grid of Laser Spots

A proposed optoelectronic system, to be mounted aboard an exploratory robotic vehicle, would be used to generate a three-dimensional (3D) map of nearby terrain and obstacles for purposes of navigating the vehicle across the terrain and avoiding the obstacles. Like some other systems...

Briefs : Physical Sciences
Wide-Band, High-Quantum-Efficiency Photodetector

A design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 μm. This and similar photodetectors would afford a capability for detecting single photons...

Briefs : Physical Sciences
Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired...

Briefs : Electronics & Computers
Narrow-Band WGM Optical Filters With Tunable FSRs

Optical resonators of the whispering-gallery-mode (WGM) type featuring DC-tunable free spectral ranges (FSRs) have been demonstrated. Previously, the FSRs of WGM optical resonators were determined solely by the resonator geometries and materials: hence, the FSR of such a resonator could be...

Briefs : Electronics & Computers
Digital Beam Deflectors Based Partly on Liquid Crystals

A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beamsteering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space...

Briefs : Photonics/Optics
Compact Packaging of Photonic Millimeter-Wave Receiver

A carrier structure made from a single silicon substrate is the basis of a compact, lightweight, relatively inexpensive package that holds the main optical/electronic coupling components of a photonic millimeter-wave receiver based on a lithium niobate resonator disk. The design of the...

Briefs : Photonics/Optics
Fabrication of Submillimeter Axisymmetric Optical Components

It is now possible to fashion transparent crystalline materials into axisymmetric optical components having diameters ranging from hundreds down to tens of micrometers, whereas previously, the smallest attainable diameter was 500 μm. A major step in the fabrication process that makes...

Briefs : Photonics/Optics
Wide-Band, High-Quantum-Efficiency Photodetector

A design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 μm. This and similar photodetectors would afford a capability for detecting single photons —...

Briefs : Photonics/Optics
Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired...

Briefs : Photonics/Optics
Narrow-Band WGM Optical Filters With Tunable FSRs

Optical resonators of the whispering-gallery-mode (WGM) type featuring DC-tunable free spectral ranges (FSRs) have been demonstrated. Previously, the FSRs of WGM optical resonators were determined solely by the resonator geometries and materials: hence, the FSR of such a resonator could be...

Briefs : Photonics/Optics
Digital Beam Deflectors Based Partly on Liquid Crystals

A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beam-steering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space...

Briefs : Physical Sciences
Filter Function for Wavefront Sensing Over a Field of View

A filter function has been derived as a means of optimally weighting the wavefront estimates obtained in image-based phase retrieval performed at multiple points distributed over the field of view of a telescope or other optical system. When the data obtained in wavefront sensing and,...

Briefs : Medical
Wearable Environmental and Physiological Sensing Unit

The wearable environmental and physiological sensing unit (WEPS) is a prototype of systems to be worn by emergency workers (e.g., firefighters and members of hazardous-material response teams) to increase their level of safety. The WEPS includes sensors that measure a few key physiological...

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