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 : Information Technology
Software for Planning in a Hierarchical Processing Environment

Decision-support software based on discrete-event simulation (DES) has been undergoing development for use in planning and scheduling work in the Orbiter Processing Facility (OPF) at Kennedy Space Center. The software is also suitable for adaptation to similar use in other facilities...

Briefs : Physical Sciences
Evaluation of Droplet-Evaporation Models for Gas/Liquid Flow

A report presents an evaluation of eight mathematical models of the evaporation of liquid droplets — models that are used in the numerical simulation of a variety of gas/liquid flows, including cooling sprays, burning liquid-fuel sprays, fire-suppression sprays, and...

Briefs : Software
Program for Simulating Dynamics of Multibody Systems

The Dynamics Algorithms for Real-Time Simulation (DARTS) computer program solves the equations of motion of tree-topology, flexible, and/or multibody mechanical systems as diverse as molecules, mechanisms, robots, spacecraft, and ground vehicles. It has proven to be particularly useful for...

Briefs : Electronics & Computers
Hybrid Superconductor/Semiconductor Planar Oscillators

Hybrid high-temperature-superconductor (HTS)/semiconductor planar oscillator circuits that operate at a frequency of 8.4 GHz have been developed. In the original intended application, one of these circuits would serve as a local oscillator in a cryogenic heterodyne receiver in a spaceborne...

Briefs : Information Technology
Work-Measurement and Methods-Analysis Studies of the OPF

Two reports describe early phases of continuing studies directed toward the selection and adaptation of industrial work-measurement and methods-analysis procedures for application to the Orbiter Processing Facility (OPF) at Kennedy Space Center. These studies were prompted by a need to...

Briefs : Photonics/Optics
A High-Repetition-Rate Optical Communications Source

High-speed communications, medical applications, and semiconductor processing would all benefit from a laser that can produce stable, high-repetition-rate pulses at 1.55 micrometers. One goal of the Naval Research Laboratory's program in ultrahigh-speed communications research is to develop...

Briefs : Electronics & Computers
Transmitting Power to Sensor Circuitry via Modulated Light

Modulated (as opposed to steady) light can be used in the optical transmission of power to remotely located sensor circuitry in a system like that described in the preceding article, "General-Purpose Optically Powered Sensor and Control System" (NPO-19604). This is analogous to the use...

Briefs : Physical Sciences
Elevation Corrections for Absolute-Pressure Measurements

A method of correcting absolute-air-pressure measurements for small differences in the elevations of pressure taps and pressure transducers has been devised. The variation in air pressure with elevation is well documented; nevertheless, in such disciplines as process control and...

Briefs : Mechanical & Fluid Systems
Self-Contained Impact-Type Damper for Bellows-Type Face Seals

A self-contained impact-type damper for a bellows-type face seals suppresses dynamic instability or chatter. In current practice, damping in a typical seal is accomplished through rubbing contact between a ground (a stationary member) and a bellows or carrier as the seal translates....

Briefs : Electronics & Computers
General-Purpose Optically Powered Sensor and Control System

The figure schematically illustrates a prototype general-purpose, microprocessor-based sensor and control system in which power, data, and control signals are transmitted via optical fibers. This system serves as an experimental model for the further development of networks of remote...

Briefs : Information Technology
Model for Investigating Human Factors in an Organization

The Kennedy Space Center Human Factors Event Evaluation Model is a model to facilitate long-term gathering and analysis of data to investigate the effects of human factors on the operations of a complex organization. The model was developed specifically for use in comprehensive...

Briefs : Robotics, Automation & Control
All-Terrain Vehicle With Self-Righting and Pose Control

A small prototype robotic all-terrain vehicle features a unique drive and suspension system that affords capabilities for self righting, pose control, and enhanced maneuverability for passing over obstacles. The vehicle is designed for exploration of planets and asteroids, and could just...

Briefs : Photonics/Optics
Measuring Flow Using Spectrally Resolved Rayleigh Scattering

An experimental study has been conducted to demonstrate the feasibility of using spectrally resolved Rayleigh scattering to nonintrusively measure the instantaneous properties of the flow in a small supersonic wind tunnel. Unlike conventional probe flow measurements, Rayleigh...

Briefs : Information Technology
Consortium Benchmarking in a Competitive Environment

The Kennedy Benchmarking Clearinghouse (KBC) is an organization for implementing an emerging methodology called "consortium benchmarking" in a competitive business environment. The partners in the KBC include NASA Kennedy Space Center and a number of its contractors. Within the KBC, the...

Briefs : Physical Sciences
Thermographic Detection of Defects in Refractory Composites

Significant effort and resources are being expended to develop ceramic-matrix composite (CMC), metal-matrix composite (MMC), and polymer-matrix composite (PMC) materials for high-temperature engine components and other parts in advanced aircraft. The development of composite materials...

Briefs : Photonics/Optics
Pulse Shepherding in Nonlinear Fiber Optics

Pulse shepherding is a nonlinear signal-propagation phenomenon that can occur when several pulses of light at different wavelengths are launched simultaneously or nearly simultaneously along the same single-mode optical fiber under suitable conditions. As its name suggests, pulse shepherding involves...

Briefs : Software
Software for Scheduling Use of Shared Resources

The Quick Utility for Intelligence Planning and Scheduling (QUIPS) computer program automates the scheduling of resources that must be shared among multiple tasks or groups. Designed to aid coordination of military intelligence operations at the division and brigade levels, QUIPS might also prove...

Briefs : Mechanical & Fluid Systems
Passive Magnetic Bearings With Ferrofluid Stabilization

Permanent-magnet rotary bearings with ferrofluid stabilization in the axial degree of freedom are undergoing development. These bearings are totally passive, yet stable in all degrees of freedom. In contrast, previously developed electromagnet and permanent-magnet bearings all exhibit...

Briefs : Motion Control
Large Gimbal Mount Enables Focal-Plane Testing

The latest missile guidance and tracking guidance systems deliver unprecedented performance, in terms of range, precision, and the ability to function in very unfavorable atmospheric conditions. These systems rely on a new generation of high-resolution, multifunction focal plane arrays to image...

Briefs : Electronics & Computers
ASIC for Viterbi Decoding With 2 ≤ K ≤ 15 and 1/2 ≥ r ≥ 1/6

An application-specific integrated circuit (ASIC) serves as a building block for a digital system that effects maximum-likelihood decoding of a Viterbi code (a binary convolutional error-correcting code) with a constraint length (K) in the range of 2 through 15 and a rate (r) in...

Briefs : Electronics & Computers
Fabricating Diffusion-Cooled Hot-Electron-Bolometer Elements

Microbridges that constitute the superconducting-transition sensory elements of electron-diffusion-cooled hot-electron bolometers can now be fabricated in increased yield and quality. This improvement is made possible by a fabrication process that notably includes the use of a...

Briefs : Software
Software for Processing SAR Images of the Polar Oceans

The RADARSAT/ERS-1,2 Geophysical Processor System (RGPS) is an automated system of hardware and software that processes synthetic-aperture-radar (SAR) images of ice and open water in polar oceans to generate higher-level geophysical-data products. Information in such products includes the...

Briefs : Information Technology
Diagnosing Helicopter Gearboxes Using Connectionist Networks

A method of automated diagnosis of helicopter gearboxes involves processing of selected features of digitized outputs of vibration sensors via structure-based connectionist networks (SBCNs), which are mathematical constructs that incorporate elements from the disciplines of dynamical...

Briefs : Software
Software for Development of Spacecraft-Simulation Programs

DARTS Shell (Dshell) is a multimission spacecraft simulator for the development, integration, and test of flight software and hardware. Dshell reduces the time and cost of developing simulation programs by enabling the development of the software in modular, reusable form and by...

Briefs : Physical Sciences
Mass Analyzer With Rotating Electric Fields

A device for measuring the distribution of masses in an atmosphere or plasma exploits the electrostatic deflection of ions in a rotating magnetic field. A magnetic field is not required. The device is simple to construct, can be made small, and is amenable to micromachining techniques such as LIGA...

Briefs : Photonics/Optics
Program for Analysis of a Complex Optomechanical System

The IMOS computer program contains subprograms that, collectively, provide a unique capability for multidisciplinary analysis of a system represented by a combination of mathematical models of structural (mechanical), control, thermal, and optical characteristics. One example of such a...

Briefs : Electronics & Computers
Algorithm Estimates Doppler Shift in a Received DPSK Signal

An algorithm estimates the Doppler frequency shift in a received radio signal with square-wave-pulse binary differential-phase-shift-keyed (DPSK) modulation. [With little modification, the algorithm is also extensible to M-ary (where M is an integer > 2) DPSK modulation with pulse...

Briefs : Software
Software for Tracking the Performance of Other Software

The Flight Software Memory Tracker (FMT) computer program is a collection of utility subprograms developed for use on the ground to track images of the flight software (FSW) in the computers aboard the Cassini spacecraft. [As used here, "images" signifies both (1) the memory load and...

Briefs : Physical Sciences
Production of Tar in Pyrolysis of Large Biomass Particles

A paper presents a study of the production of tar in the pyrolysis of spherical biomass particles, with computational simulations performed by using the macroparticle portion of the model described in "Generalized Mathematical Model of Pyrolysis of Plant Biomass" (NPO-20068) elsewhere...

Briefs : Materials
Phospha-s-Triazines and Other Compounds for Use as Additives

A report describes research on selected compounds as additives to perfluoroalkyether (PFPAE) fluids that are used as synthetic lubricants for metal parts. Additives are needed to inhibit both thermo-oxidative degradation of, and corrosion of metals by, the PFPAE fluids in the presence...

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