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Briefs: Information Technology
A fine-pointing scheme that involves correlation of images and maximum-likelihood estimation has been proposed to enable tracking of optical sources. This scheme is intended for...
Briefs: Information Technology
Quantum Superluminal Transmission of Random Messages
In a proposed communication scheme, quantum entanglement and quantum nonlocality would be utilized to effect instantaneous transmission of randomly chosen messages to remote locations. Although the messages would not convey any information, they might nevertheless be of some value under...
Briefs: Information Technology
Goal-Based Fault Tolerance for Spacecraft Systems
A report discusses the concept of goal-based fault tolerance as implemented in NASA’s Mission Data System (MDS), which is a developmental architecture for unified flight, test, and ground software that is intended to be adaptable to a variety of next-generation deep-space missions. In goal-based...
Briefs: Electronics & Computers
PWM and Synchronous Rectifier Controller ASICs
A report describes two radiation-hard application-specific integrated circuits (ASICs) that constitute a mixed-signal chip set that performs all the control functions for a power-converter module (PCM) in a spacecraft power-supply system. One of these ASICs serves mainly as a pulse-width modulation...
Briefs: Physical Sciences
DNS of a Supercritical H₂/O₂ Mixing Layer
This report discusses direct numerical simulations (DNS) of a mixing layer between supercritical flows of oxygen and hydrogen. The governing conservation equations were those of fluctuation- dissipation (FD) theory, in which low-pressure typical transport properties (viscosity, diffusivity and thermal...
Briefs: Information Technology
Remote Agent as Applied to the Deep Space 1 Spacecraft
A report presents updated information about the Remote Agent — a reusable artificial-intelligence software system that was described in “A Remote Agent Prototype for Spacecraft Autonomy” (NPO-19992), NASA Tech Briefs, Vol. 21, No. 3 (March 1997), page 106. This system was conceived to...
Briefs: AR/AI
Multirover Coordination Based on Contract Net Protocol
A computer program coordinates operations of multiple cooperating rovers (small exploratory robotic vehicles deployed from a lander spacecraft), each of which is equipped with computer hardware and software that schedule the tasks assigned to it. The program implements a contract net protocol...
Briefs: Mechanical & Fluid Systems
Pneumatic Accelerator for Launching a Spacecraft
A report proposes the development of a ground-based launch-assist apparatus that would accelerate a spacecraft to a speed of about 270 m/s. The apparatus would include a track along which the spacecraft would ride on a sled coupled to a large piston driven by compressed air along a tube (more...
Briefs: Photonics/Optics
A portable instrumentation system that includes an airborne and a ground-based subsystem acquires multispectral image data over swaths of terrain ranging in width from about 1/2 to 1 km. The system...
Briefs: Photonics/Optics
A lossless image-compression algorithm that can be executed entirely in electronic hardware has been developed. This algorithm yields about 15 percent more compression than does the...
Briefs: Physical Sciences
A highly sensitive, low-power, low-noise multifunctional active-excitation spectral analyzer (MAESA) that would span the wavelength range of 0.5 to 2.5 µm and would operate near room...
Briefs: Photonics/Optics
Software and electronic hardware are being developed to provide cockpit guidance and camera control for an air-to-air schlieren photography system that is to be used to take high-resolution...
Briefs: Photonics/Optics
Hand-Held Optoelectronic Particulate Monitors
Optoelectronic instruments are being developed for use in measuring the concentrations and sizes of microscopic particles suspended in air. The instruments could be used, for example, to detect smoke, explosive dust in grain elevators, or toxic dusts in industrial buildings. Like some older,...
Briefs: Imaging
High-Performance Processor of Hyperspectral Images
The Remote Sensing Hyperspectral Engine (RSHE) is a special-purpose, portable computer that performs high-performance processing of hyperspectral image data collected by a remote-sensing optoelectronic apparatus. Typically, the remote-sensing apparatus is airborne or spaceborne, the images are of...
Briefs: Photonics/Optics
Arrays of HgCdTe infrared photodetectors have been developed to satisfy stringent performance requirements for use in NASA’s Tropospheric Emission Spectrometer. The design of these...
Briefs: Physical Sciences
The Propulsion group at Dryden Flight Research Center is performing analyses of the effectiveness of chemical-species sensors for detecting and assessing leakage. The group is also...
Briefs: Motion Control
Equipment for Removal of EDM Water Filters
An assembly of lifting equipment has been devised to enable the safe removal of water filters used in electrical-discharge machining (EDM). As explained below, this equipment prevents injuries of a type formerly associated with changing the filters.
Briefs: Physical Sciences
Micromachined Emitter/Bolometer Structures for Infrared Gas Sensors
Infrared gas sensors that could be mass-produced at relatively low cost have been proposed for a variety of applications — for example, detecting carbon monoxide in air inside houses. A sensor of this type would include a housing into which ambient air could diffuse. The gas of...
Briefs: Motion Control
Measuring Turbomachine-Blade Deflections in Two Dimensions
A report describes a method of simultaneously measuring steady-state axial and tangential turbomachine-blade deflections by use of fiber-optic probes and probe actuators designed specifically for this purpose. Each fiber-optic probe illuminates a small spot and, by measuring a change in...
Briefs: Motion Control
Motorized Rotator for an Ultrasonic Probe
An apparatus has been devised to enable accurate, reproducible angular positioning of an ultrasonic probe used to diagnose the carotid artery. More specifically, the apparatus is intended for use in a clinical setting in which the intima-media thickness (IMT) of the carotid artery is measured by use of...
Briefs: Motion Control
Progress in Magnetoelastic Vibration Dampers
A report describes uniaxial-stress-versus-strain experiments that were performed on polycrystalline Tb76Dy24 alloy specimens. [Also see "Magnetoelastic Vibration Dampers" (NPO-20988) on page 56 of this issue.] The proposal is to use Tb-Dy alloys as vibration-damping materials at temperatures -100 K,...
Briefs: Electronics & Computers
Complementary metal oxide semiconductor (CMOS) integrated-circuit image sensors that are highly tolerant of high-energy radiation ("radiation hard") are undergoing development. These devices are sensitive...
Briefs: Motion Control
Software for Analyzing Traversability of Terrain
Grid-Based Estimation of Surface Traversability Applied to Local Terrain (GESTALT) is a software library that helps a robotic wheeled vehicle choose a safe path across nearby terrain. The input to GESTALT consists mainly of three-dimensional range measurements of the nearby terrain taken by sensors...
Briefs: Physical Sciences
Deployable Shell Structures With Shape-Control Actuators
Advanced control systems that include built-in smart-material elastic-deformation structural actuators have been proposed for deployable thin-shell structures that are required to be maintained in precise shapes once deployed. This approach to structural shape control was conceived to enable...
Briefs: Motion Control
The figure depicts the Legged Excursion Mechanical Utility Robot (LEMUR) - a six-legged robot for demonstrating robotic capabilities for assembly, maintenance, and inspection. LEMUR is designed to be capable of...
Briefs: Mechanical & Fluid Systems
An active-control surface modal (ACSM) device has been developed as an improved means of alleviating buffet of an aircraft. The ACSM device is a "smart" actuator system that includes an array...
Briefs: Motion Control
The figure depicts a tendon-driven, three-fingered robot hand (or foot, depending on one's perspective) designed to be installed on the end of the left front leg of the six-legged robot...
Briefs: Electronics & Computers
The figure depicts the basic geometric features of an antenna system designed to be part of a miniature atmosphere-sounding passive microwave radiometer to be flown at high altitude...
Briefs: Motion Control
Magnetoelastic Vibration Dampers
Magnetoelastic dampers have been proposed for use in suppressing vibrations of large motors and transformers that operate at temperatures below 100 K. [Also see "Progress in Magnetoelastic Vibration Dampers," (NPO-20887) on page 57 of this issue.] These dampers would be made of magnetostrictive materials -...
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