November 2001

Briefs : Mechanical & Fluid Systems
Saturation Technique for Rapid Binary Image Processing

An improved technique of limited-precision arithmetic has been devised for use in convolutional filtering of image data prior to conversion of the data to binary form. Both limited-precision arithmetic and conversion to binary form reduce the volume of data, thereby contributing to...

Briefs : Electronics & Computers
Network for Forecasting Weather and Diffusion of Toxins

The Meteorological Range Safety Support System/Eastern Range Dispersion Assessment System (MARSS/ERDAS) is a system of interconnected computer workstations designed to acquire, process, and disseminate nearly real-time meteorological data and outputs of mathematical models of the...

Briefs : Software
Software for Processing Serial Cross Sections Into 3D Images

The Reconstruction of Serial Sections (ROSS) computer program processes data from a series of tomograms to generate a three-dimensional (3D) representation of an object, and further processes data from the 3D representation to enable the viewing of any part of the object from any of an...

Briefs : Software
Software for Displaying and Comparing Wind-Tunnel Data

DARWIN is a computer program that provides access, via the Internet, to geographically dispersed NASA computer archives of both meta-data and raw test data from wind tunnels and raw simulation data from computational fluid dynamics (CFD) sites. DARWIN facilitates the manipulation and...

Briefs : Physical Sciences
Integrated Environmental Monitoring Instrument

A miniature, battery-powered, semiautonomous environmental monitoring instrument contains advanced meteorological sensors, a Global Positioning System (GPS) receiver for determining its position, radio-communication circuitry, and a controller that performs measurement, control, and...

Briefs : Electronics & Computers
Improved Model of Spectral Response of an HEB Mixer

An improved mathematical model enables the somewhat more accurate prediction of the spectral response of a mixer circuit (see figure) that comprises a twin-slot antenna coupled via coplanar waveguides to a hot-electron bolometer (HEB). The development of the improved model is part of a...

Briefs : Electronics & Computers
Improved Charge-Termination Technique for Lithium-Ion Cells

An improved charge-termination technique has been developed to obtain a more accurate balance between charge and discharge of rechargeable lithium-ion-based electrochemical cells and batteries. The technique has been demonstrated experimentally and is now in use in a laboratory battery...

Briefs : Electronics & Computers
Equipment for On-Wafer Testing at Frequencies Up to 220 GHz

A suite of electronic test equipment has been developed for use in the measurement of key electrical characteristics of advanced, high-speed integrated circuits for communications, radar, digital networks, imaging systems, and other applications. More specifically, the test equipment is...

Briefs : Software
Software for Ground Operations for a Prototype Mars Rover

A software system has been developed for use in Earth operations centers communicating with a robotic exploratory vehicle (rover) on Mars. The software was designed for and field-tested on the Field Integrated Design and Operations rover — a prototype similar to rovers of the...

Briefs : Software
Software Processes SRTM ScanSAR Data Into Topographical Maps

A computer program automatically generates topographical maps from data collected by scan-mode synthetic-aperture radar (scanSAR) during the Shuttle Radar Topography Mission (SRTM). A preprocessing subprogram subdivides the SAR data, along with ancillary spacecraft-motion,...

Briefs : Software
Algorithm for Autonomous Visual Discovery

An algorithm that can discover potentially interesting objects in image data has been formulated and implemented in software. The algorithm is intended for applications in which the target objects are mathematically ill-defined and/or not known or specified in advance. Potential applications...

Briefs : Software
Computer Program Generates Test Cases

An Automated Test Case Generator computer program generates parameter-based test cases for testing software and hardware systems. Given N parameters — each of which represents a kind of variation for testing — and a finite set of possible values for each parameter, the program generates...

Briefs : Software
Software Manages Documentation in a Large Test Facility

The 3MCS computer program assists an instrumentation engineer in performing the 3 essential functions of design, documentation, and configuration management of measurement and control systems in a large test facility — initially, a propulsion-system test facility at Stennis Space...

Briefs : Software
Software Performs Testing, Monitoring, and Control Functions

The Front End Processor (FEP) Real-Time Embedded Software performs command and data-processing functions for an aeronautical MIL-STD-1553B telemetry link and ground support equipment (GSE) in a spacecraft-equipment-testing environment. The FEP is used in the Test, Control, and...

Briefs : Materials
Relatively Simple Atmospheric-CO2 Controller

An apparatus has been developed as a means of controlling the partial pressure of CO2 (pCO2) in air in a closed or semiclosed environmental system. The apparatus takes CO2 from the air in a source chamber and supplies the CO2, at a regulated partial...

Briefs : Materials
A Technique for Injecting Ag+ Ions as Biocide into H2O

A simple and reliable technique facilitates the addition of silver ions to water supplies to suppress bacterial contamination. In the original application for which the technique was devised, there is a need for Ag+-ion concentrations at a biocidal levels (0.5 mg/L) in 44-L...

Briefs : Mechanical & Fluid Systems
Breathing-Air and Cooling Apparatus for Protective Suit

The figure schematically illustrates a portable life-support apparatus for any of a variety of protective suits to be worn in hostile environments. A prototype of the apparatus has been fitted to space suits for use underwater. Astronauts wear these suits during training dives in a tank of...

Briefs : Mechanical & Fluid Systems
Thermoelectric Contact Cooler/Freezer

A thermoelectric contact cooler/ freezer is designed to utilize thermal conduction to rapidly freeze blood and urine samples in test tubes and syringes. This apparatus is dependable, wastes little energy, contains no moving parts other than a fan, can operate in a wide temperature range and in any...

Briefs : Physical Sciences
Molten-Carbonate Electrolyzers for Making CO and O2

Electrochemical cells in which molten carbonates would serve as electrolytes have been proposed for use in electrolyzing CO2. The proposal was made in an effort to implement a concept of in situ resource utilization (ISRU) for the exploration of Mars; the basic idea is to generate CO...

Briefs : Physical Sciences
Improved Spherical Energy Analyzer

An improved spherical energy analyzer (a type of electrostatic mass spectrometer) is under development for use in analyzing a beam of ions generated by a Hall thruster. The major improvement, relative to a commercial spherical energy analyzer, is the addition of a quadrupole stage (with refocusing electron...

Briefs : Physical Sciences
Redundant Oxygen-Deficiency Monitoring System

An oxygen-deficiency monitoring system (ODMS) has been developed for a ten-room facility in which the use of large amounts of nitrogen and helium could cause an oxygen deficiency severe enough to be hazardous to personnel. The ODMS comprises three subsystems, of which two monitor three rooms...

Briefs : Mechanical & Fluid Systems
Theory of Formation-Flying Control for Multiple Spacecraft

A report presents the mathematical basis of a method of controlling multiple spacecraft flying in formation, subject to control constraints. The spacecraft are assumed to be equipped with relative-position-sensing, relative-velocity-sensing, and communication infrastructure, and...

Briefs : Information Technology
Self-Organization Based on Quantum Entanglement

A report presents a theoretical study of communication among intelligent agents in the presence of quantum entanglement and the absence of classical (in the sense of non-quantum) communication channels. Several paradigms of self-organization based on quantum entanglement are introduced and...

Briefs : Mechanical & Fluid Systems
Onboard Estimation of Times of Periapsis During Aerobraking

A report proposes a technique for onboard updating of the orbital period of an aerobraking spacecraft in order to estimate the time of the next periapsis. The time of periapsis is nearly centered in the middle of the drag pass, and provides a convenient reference time for events in the...

Briefs : Physical Sciences
Report on User's Guidefor Monthly Vector Wind Profile Model

A report briefly describes a user's guide for a computer program that constructs vector wind profiles on the basis of a statistical model. The monthly vector wind profiles are meant to be used (1) to estimate wind-dispersion-related dispersions of critical aerodynamic loads and...

Briefs : Materials
Experiments on Residual-Stress Bondline Failures in an RSRM

A report describes an experimental study undertaken to verify a finite-element mathematical model used to predict residual stresses and stress-induced failures in the adhesive interfacial layers (bondlines) that join phenolic liners to interior surfaces of metal housings of...

Briefs : Mechanical & Fluid Systems
Improved Micromachined Vaporizing-Liquid Microthruster

A report describes an improved micromachined vaporizing-liquid microthruster (VLM), now under development as a prototype of thrusters for microspacecraft. This thruster is of the resistojet type: the energy for vaporization and expansion of a propellant liquid is provided through...

Briefs : Physical Sciences
Sizes of Surface and Capped InxGa1-xAs/GaAs Quantum Dots

A report describes an experimental study of the sizes and concentrations of capped (buried) and surface In0.6Ga0.4As/GaAs quantum dots that were grown by metal-organic vapor deposition under the same conditions except for the inclusion or exclusion of capping....

Briefs : Physical Sciences
Fuel Cell Would Generate Power From Martian Atmosphere

A report proposes the development of a thin-film fuel cell that would generate electric power from two minor constituents of the Martian atmosphere — O2 and CO. These compounds are generated continuously by photolysis of CO2, the major constituent. The fuel cell...

Briefs : Photonics/Optics
System for Measuring Three Tilts and Distance of an Object

An optoelectronic system discussed herein measures the state of alignment (SOA) of an object under test in four of its six degrees of freedom (DOFs). This system was originally intended for use in determining the SOA of an optical bench in a vacuum chamber. The basic design and mode of...

Briefs : Photonics/Optics
Thermal Imaging for Diagnosing Fuel Cells

Thermal (that is, infrared) imaging has been demonstrated to be an effective technique for the diagnosis of operating fuel cells and fuel-cell stacks. Thermal imaging can be used to identify a variety of phenomena, described below, that are associated with nonuniform generation of heat. Hence, thermal...

Briefs : Photonics/Optics
Tunable Ultraviolet Light Source for Combustion Experiments

An ultraviolet light source that comprises a tunable diode laser and associated optics provides the optical excitation needed for simultaneous wavelength-modulation-absorption spectroscopy (WMS) and laser-induced-fluorescence (LIF) measurements in experiments on combustion. These...

Briefs : Physical Sciences
Fourier-Transform X-Ray Microscope

A proposed x-ray instrument - a Fourier-transform x-ray microscope - would enable high-resolution imaging of objects with sizes of the order of 20 nm. (This size range is typical of cell organelles.) The instrument would also offer a spectroscopic capability for the sensitive detection and identification of...

Briefs : Photonics/Optics
Ring-Resonator/Bragg-Grating Laser-Feedback Elements

Integrated optical structures that contain ring resonators and Bragg gratings have been proposed as external feedback elements for semiconductor lasers. These feedback elements would constrain the laser spectra to narrow lines (more precisely, narrow spectral bands) centered at desired...

Briefs : Photonics/Optics
Computer Program for Designing Diffractive Optics

AMPERES is a prototype computer program that implements the algorithm, described in the preceding article, for optimizing designs of diffractive optics. Several other programs for designing refractive optics are commercially available, but they offer very limited capabilities with respect to...

Briefs : Photonics/Optics
Fiber-Optic Illumination for Microscope

In a simple but very effective method for providing intense illumination of an opaque specimen under a microscope, light is supplied via an optical fiber. This system eliminates the need for traditional Köhler-type vertical illumination system components, such as beam splitters and lenses, and is easily...

Briefs : Photonics/Optics
Algorithm for Optimizing Designs of Diffractive Optics

An algorithm for optimizing the designs of diffractive optics is based on constrained dynamics and the reciprocity of electromagnetic propagation. This algorithm can contribute to realization of the potential of diffractive optics, which offer capabilities greater than those of refractive...

Briefs : Photonics/Optics
Improved Etalon-Type Fiber-Optic Hydrogen Sensors

Three modifications have been proposed for hydrogen sensors in which hydrogen in the air causes changes in the reflection spectra of interferometric film stacks that are interrogated via optical fibers. One of the films in the stack in each such sensor contains palladium, which reacts with...

Briefs : Photonics/Optics
Wavelength-Agile External-Cavity Diode Laser

A prototype wavelength-agile external-cavity diode laser (ECDL) was demonstrated in the first phase of a continuing effort to develop noninvasive laser-based instruments that would measure absolute concentrations of trace gases. As envisioned, these instruments would offer a combination of high...

Briefs : Photonics/Optics
Enhanced Optical Microresonators for Detecting Molecules

Sensors based on microscopic optical resonators and arrays of such resonators have been proposed for detecting trace amounts of specific molecules in small gaseous, liquid, and solid samples. In addition to compactness, these sensors would offer ultrahigh sensitivity - in some cases,...