October 2004

Briefs : Electronics & Computers
Inter-Valence-Subband/Conduction-Band-Transport IR Detectors

Infrared (IR) detectors characterized by a combination of (1) high-quantum-efficiency photoexcitation of inter-valence-subband transitions of charge carriers and (2) high-mobility conduction-band transport of the thus-excited charge carriers have been proposed in an effort to develop...

Briefs : Mechanical & Fluid Systems
Miniature Robotic Submarine for Exploring Harsh Environments

The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration—especially, looking for signs of life—in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine...

Briefs : Mechanical & Fluid Systems
Lightweight Exoskeletons With Controllable Actuators

A proposed class of lightweight exoskeletal electromechanical systems would include electrically controllable actuators that would generate torques and forces that, depending on specific applications, would resist and/or assist wearers' movements. The proposed systems would be successors to...

Briefs : Manufacturing & Prototyping
Progress in Fabrication of Rocket Combustion Chambers by VPS

Several documents in a collection describe aspects of the development of advanced materials and fabrication processes intended to enable the manufacture of advanced rocket combustion chambers and nozzles at relatively low cost. One concept discussed in most of the documents is the...

Briefs : Information Technology
Indentured Parts List Maintenance and Part Assembly Capture Tool — IMPACT

Johnson Space Center’s (JSC's) indentured parts list (IPL) maintenance and parts assembly capture tool (IMPACT) is an easy-to-use graphical interface for viewing and maintaining the complex assembly hierarchies of large databases. IMPACT, already in use at JSC to...

Briefs : Information Technology
Fast Query-Optimized Kernel-Machine Classification

A recently developed algorithm performs kernel-machine classification via incremental approximate nearest support vectors. The algorithm implements support-vector machines (SVMs) at speeds 10 to 100 times those attainable by use of conventional SVM algorithms. The algorithm offers potential...

Briefs : Information Technology
Forensic Analysis Specialists Discover Product Failure Causes Using FEA Software

Engineers use a wide range of tools and techniques to ensure that the designs they create are safe. However, accidents sometimes happen and when they do, companies need to know if a product failed because the design was inadequate or if some other cause, such as...

Briefs : Information Technology
Software Reduces Radio-Interference Effects in Radar Data

A computer program suppresses the effects of narrow-band radio-frequency interference (RFI) on the data collected by a wide-band radar system. The need for this program arises because some advanced wide-band synthetic-aperture radar systems utilize frequency bands that include frequencies...

Briefs : Information Technology
Coordinating Shared Activities Shared Activity

Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common...

Briefs : Information Technology
Software For Use With Optoelectronic Measuring Tool

A computer program has been written to facilitate and accelerate the process of measurement by use of the apparatus described in "Optoelectronic Tool Adds Scale Marks to Photographic Images" (KSC-12201), NASA Tech Briefs, Vol. 27, No. 1 (January 2003), page 6a. To recapitulate: The tool...

Briefs : Materials
Using Iron To Treat Chlorohydrocarbon Contaminated Soil

A method of in situ remediation of soil contaminated with chlorinated hydrocarbon solvents involves injection of nanometer-size iron particles. This method should not be confused with a similar method, involving injection of emulsified iron particles, reported in "Treatment To Destroy...

Briefs : Mechanical & Fluid Systems
Simple Systems for Detecting Spacecraft Meteoroid Punctures

A report describes proposed systems to be installed in spacecraft to detect punctures by impinging meteoroids or debris. Relative to other systems that have been used for this purpose, the proposed systems would be simpler and more adaptable, and would demand less of astronauts'...

Briefs : Mechanical & Fluid Systems
Mechanism for Self-Reacted Friction Stir Welding

A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below.

Briefs : Mechanical & Fluid Systems
Back Actuators for Segmented Mirrors and Other Applications

Back actuators have been proposed as alternatives to edge actuators considered previously for use in aligning hexagonal segments of lightweight segmented astronomical mirrors planned for use in outer space. The proposed back actuators could also be useful on Earth as parts of...

Briefs : Mechanical & Fluid Systems
Thermally Insulating, Kinematic Tensioned-Fiber Suspension

Figure 1 shows a salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic demagnetization refrigerator (ADR). “Salt pill” in this context denotes a unit comprising a cylindrical container, a matrix of gold wires...

Briefs : Physical Sciences
Electron-Spin Filters Based on the Rashba Effect

Semiconductor electron-spin filters of a proposed type would be based on the Rashba effect, which is described briefly below. Electron-spin filters — more precisely, sources of spin-polarized electron currents — have been sought for research on, and development of, the emerging...

Briefs : Physical Sciences
Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The...

Briefs : Physical Sciences
Improved Position Sensor for Feedback Control of Levitation

An improved optoelectronic apparatus has been developed to provide the position feedback needed for controlling the levitation subsystem of a containerless processing system. As explained below, the advantage of this apparatus over prior optoelectronic apparatuses that have served this...

Briefs : Physical Sciences
Relative-Motion Sensors and Actuators for Two Optical Tables

Optoelectronic sensors and magnetic actuators have been developed as parts of a system for controlling the relative position and attitude of two massive optical tables that float on separate standard air suspensions that attenuate ground vibrations. In the specific application for...

Briefs : Electronics & Computers
Compact Tactile Sensors for Robot Fingers

Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure-or force-distribution feedback provided by these sensors is essential for the further...

Briefs : Electronics & Computers
Improved Ion-Channel Biosensors

An effort is underway to develop improved biosensors of a type based on ion channels in biomimetic membranes. These sensors are microfabricated from silicon and other materials compatible with silicon. As described below, these sensors offer a number of advantages over prior sensors of this type.

Briefs : Electronics & Computers
Suspended-Patch Antenna With Inverted, EM-Coupled Feed

An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna (see Figure 1) includes a parasitic patch on top of a suspended dielectric superstrate, an...

Briefs : Electronics & Computers
System Would Predictively Preempt Traffic Lights for Emergency Vehicles

Two electronic communication-and- control systems have been proposed as means of modifying the switching of traffic lights to give priority to emergency vehicles. Both systems would utilize the inductive loops already installed in the streets of many municipalities to detect...

Briefs : Electronics & Computers
Hyperboloid Wire Basket Connector Technology Provides High-Performance Interconnect Solutions

As high-end electronics become more and more pervasive, reliability and the need to minimize failure are top priorities for many manufacturers. Traditionally, reliability has been a key issue for military, aerospace, and lifecritical systems. Today,...

Briefs : Electronics & Computers
CHEM-Based Self-Deploying Spacecraft Radar Antennas

A document proposes self-deploying spacecraft radar antennas based on cold hibernated elastic memory (CHEM) structures. Described in a number of prior NASA Tech Briefs articles, the CHEM concept is one of utilizing open-cell shape-memory-polymer (SMP) foams to make lightweight structures that...

Briefs : Electronics & Computers
Scalable Multiprocessor for High-Speed Computing in Space

A report discusses the continuing development of a scalable multiprocessor computing system for hard real-time applications aboard a spacecraft. "Hard real-time applications" signifies applications, like real-time radar signal processing, in which the data to be processed are generated at...

Briefs : Electronics & Computers
Additional Drive Circuitry for Piezoelectric Screw Motors

Modules of additional drive circuitry have been developed to enhance the functionality of a family of commercially available positioning motors (Picomotor™ or equivalent) that provide linear motion controllable, in principle, to within increments ≤30 nm. A motor of this type includes...

Briefs : Electronics & Computers
Optical Position Encoders for High or Low Temperatures

Optoelectronic pattern-recognition systems (optical encoders)for measuring positions of objects of interest at temperatures well below or well above room temperature are undergoing development.At present,the development effort is concentrated on absolute linear, rotary, and Cartesian...

Briefs : Photonics/Optics
Tunable Optical True-Time Delay Devices Would Exploit EIT

Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters,...

Briefs : Information Technology
An Architecture for Controlling Multiple Robots

The Control Architecture for Multirobot Outpost (CAMPOUT) is a distributed-control architecture for coordinating the activities of multiple robots. In the CAMPOUT, multiple-agent activities and sensor-based controls are derived as group compositions and involve coordination of more basic...