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 : Materials
Aggregate-Search Approach for Planning and Scheduling

Several algorithms developed for use in automated planning and scheduling of sets of interdependent activities employ aggregation techniques to increase the efficiency of searching for temporal assignments that are legal in the sense that they do not violate constraints. In the...

Briefs : Materials
Improvements in Electroformed Copper Alloys

Some success has been achieved in a development program directed toward improving the mechanical properties of electroformed copper-alloy structural components. Typical of such components are bundles of tubes and other heat-exchange devices that have complex shapes. Electroforming of copper alloys is...

Briefs : Mechanical & Fluid Systems
Dynamic Balancing of Multiple Independent Stirling Engines

Experiments have shown that an assembly of multiple free-piston Stirling engines can be designed and constructed in such a way as to both (1) make the vibrations of the engines balance each other to minimize the overall level of vibration, and (2) enable the engines to operate...

Briefs : Mechanical & Fluid Systems
Using Artificial Neural Networks To Monitor Stirling Engines

An important secondary topic addressed in the research and development effort described in the preceding article is the use of artificial neural networks to improve the monitoring and thus the control and safety of multiple free-piston Stirling engines. Information collected by...

Briefs : Mechanical & Fluid Systems
Tooling for Controlled Grinding of an Edge To Remove Defects

A special-purpose grinding tool and fixtures have been developed for reworking an edge of a seal surface on a nozzle-throat-support housing in a rocket engine (see Figure 1) to remove defects caused by corrosion. Although the design of the tooling is specific to the original...

Briefs : Information Technology
Cascade Error-Projection Learning in Neural Networks

Cascade error projection (CEP) is an improved learning algorithm for artificial neural networks. CEP is reliable and suitable for efficient implementation in very-large-scale integrated (VLSI) circuitry. In comparison with other neural-network-learning algorithms, CEP involves fewer iterations...

Briefs : Information Technology
Expert System Controls and Monitors Thermal System

The Thermal Expert System (TEXSYS) computer program exerts real-time control over a complicated thermal-regulatory system that includes evaporators, condensers, a pump, valves, and sensors. TEXSYS observes differences between actual and expected conditions and analyzes differences to determine...

Briefs : Physical Sciences
Biomorphic Gliders

Biomorphic gliders are small robotic microflyers proposed for use in scientific exploration of planetary atmospheres and terrains that capture some key features of insect and bird flight. Biomorphic gliders as biomorphic flight systems are a subset of biomorphic explorers. The multidisciplinary system concept of "Biomorphic...

Briefs : Physical Sciences
High-Heat-Flux Thermogravimetric Analysis With Radiography

A process and a laboratory setup to implement the process (see figure) have been devised to enable the acquisition of time-resolved data on the thermal decomposition of a specimen of a solid material exposed to a heat flux comparable to the heat flux in a typical rocket engine. The...

Briefs : Physical Sciences
Thermogravimetric Analysis With Laser Heating

Laser thermogravimetric analysis (laser TGA) is a technique that yields time-resolved data on the thermal decomposition of a specimen of a solid material exposed to a heat flux comparable to the heat flux in a typical rocket engine. Like the technique described in the preceding article, laser TGA...

Briefs : Mechanical & Fluid Systems
Stable Microwave-Beam-Riding Spacecraft

The work considers passive dynamic stability of sail craft, propelled by microwave beams. Such systems are under consideration as low-cost means of interstellar travel. Sail-craft shapes offering passive dynamic (neutral) stability are identified. Passive stability is a key mission-enabling attribute. Very...

Briefs : Physical Sciences
Ultralight Balloon Systems for Exploring Uranus and Neptune

A report proposes ultralight balloon systems to carry a 10-kg payload, including scientific instruments for exploring the atmospheres of Uranus and Neptune. The system masses to be transported to those planets would be kept low by not transporting balloon-inflating gases. Each...

Briefs : Materials
Foaming in Place for Outer-Space Applications

A report discusses the adaptation of foaming-in-place techniques and materials to outer-space applications. Foaming in place is used commercially in terrestrial sealing, insulating, bonding, and retrofitting applications. The room-temperature outer-space versions of foaming in place are...

Briefs : Photonics/Optics
Leakage-Preventing Design of Snapshot Photodiode CMOS Imager

A new design for a complementary metal oxide/semiconductor (CMOS) snapshot imaging device of the photodiode-based, active-pixel-sensor (APS) type calls for features to prevent photogenerated electric charges collected during a given frame period from leaking into in-pixel capacitors...

Briefs : Motion Control
Advanced, Lightweight, Low-Power-Consumption Actuator Brake

An advanced, lightweight, low-power consumption brake has been developed to satisfy NASA's special requirements for use on actuators during spaceflight. This brake can increase the stopping, holding, and parking ability of a spacecraft while reducing its electrical power consumption....

Briefs : Photonics/Optics
Microsphere and Microcavity Optical-Absorption Sensors

Miniature high-resolution optical-absorption sensors for detecting trace amounts of chemical species of interest in gas and liquid samples are undergoing development. The transducer in a sensor of this type is a fiber-optic-coupled optical resonator in the form of a transparent microsphere,...

Briefs : Motion Control
Controlling Speed of a Robotic Vehicle Over Rough Terrain

A method of computing the speed at which to command an autonomous robotic vehicle to travel over rough terrain has been devised. The method amounts to a robotic implementation of the practice in which, during approach to a visibly rough surface, a human driver intuitively reduces the...

Briefs : Photonics/Optics
Confocal Single-Mode-Fiber-Optic Raman Microspectrometer

A proposed optoelectronic apparatus would perform the combined functions of a confocal microscope and a Raman spectrometer. It would be used to acquire Raman-spectral-image and/or monochromatic-image data from mineral and/or biological specimens with high three-dimensional spatial...

Briefs : Photonics/Optics
Coarse Alignment of a Segmented Telescope Mirror

A method of coarse alignment has been proposed for a primary telescope mirror that comprises multiple segments mounted on actuators that can be used to tilt and translate the segments to effect wavefront control in increments as fine as a fraction of a wavelength of light. The method was...

Briefs : Photonics/Optics
Highly Oblate Microspheroid as an Optical Resonator

Experiments have shown that a highly oblate microspheroid made of low-dielectric-loss silica glass can function as a high-performance optical resonator. The shape of this resonator (see figure) is intermediate between that of (1) microdisk or microring resonators and (2) microsphere...

Briefs : Motion Control
Estimation of Wheel-Contact State of a Robotic Vehicle

A method of estimating the state of contact between (1) the wheels of a robotic vehicle equipped with a rocker-bogey suspension and (2) the ground has been devised. The contact-state information is used to estimate the position of the vehicle with an accuracy greater than that achievable by...

Briefs : Photonics/Optics
Software for Generating Mosaics of Astronomical Images

Software is being developed to "stitch" together multiple astronomical images of small, adjacent patches of the sky into a single mosaic image of a large portion of the sky. These mosaics make data from large areas of the sky readily available for efficient viewing of many types of...

Briefs : Photonics/Optics
Ion-Exchange Films for Luminescence Spectrometry of Rare-Earth Ions

Thin, initially transparent films made of variants of a polymeric cation-exchange material have been found to be useful for facilitating the luminescence detection and quantitation of several rare-earth ions dissolved in aqueous solutions. A film of this type is prepared in an...

Briefs : Information Technology
Partial Subtractive Dither for Lossy Data Compression

A technique of partial subtractive dither has been developed to improve the performance of any of a variety of near-lossless data-compression algorithms. The technique may be applicable to compression of scientific and medical image data.

Briefs : Electronics & Computers
Acquisition, Tracking, and Pointing in Optical Communication

A document in the form of lecture slides outlines a program of development of capabilities for acquisition of signals, tracking of signal sources, and pointing of transmitters and receivers in deep-space optical communications. Topics addressed on the first few slides include the...

Briefs : Information Technology
Software for Preprocessing of Raw SAR Data

The SAR Processing System Raw Data Processor (SPS RDS) computer program is used in the Alaska SAR Facility (ASF) to scan and decode raw data that have been downlinked from the European Remote Sensing Satellite (ERS), the Japanese Earth Resources Satellite (JERS), and the RADARSAT (a Canadian...

Briefs : Electronics & Computers
Variable Telemetry Playback Rate for Increased Data Return

In a scheme to increase the overall data return from a phase-modulation, suppressed-carrier telemetry transmitter, the telemetry playback symbol rate is adjusted essentially continuously. More precisely, the playback symbol rate is adjusted frequently (as often as once per symbol...

Briefs : Information Technology
Software for Locating Heterogeneous Data in Different Places

The Object Oriented Data Technology group at NASA's Jet Propulsion Laboratory is developing software for locating data — especially scientific data — stored in various formats on heterogeneous computer systems at different locations. The software is intended to exploit and extend...

Briefs : Test & Measurement
Measuring Contact Angles of a Sessile Drop and Imaging Convection Within It

Figure 1 depicts an apparatus that simultaneously and synchronously records magnified ordinary top-view video images and laser-shadowgraph video images of a sessile drop. The real-time values of contact angle and rate of evaporation of the drop as functions of time can...

Briefs : Electronics & Computers
Improved Encryption-Mode GPS Receiver

An improved Global Positioning System (GPS) receiver, which processes an encrypted P-code signal without knowledge of the encryption code (denoted here as A-codeless mode), includes an auxiliary antenna and associated additional signal-processing circuitry. The improved design of this receiver makes it...

Question of the Week
Will Cooling Coatings Catch On?

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