June 1998

Briefs : Motion Control
Magnetostrictive Inertial-Reaction Linear Motors

Linear-translation motors containing inertial-reaction masses driven by magnetostrictive actuator elements are undergoing development. These motors could be used to make fine position adjustments in diverse scientific and industrial instruments that operate at temperatures ranging from near...

Briefs : Mechanical & Fluid Systems
Pulse-tube Refrigerator Unit

Pulse-tube Refrigerators can be operated over a wide range of temperatures. These units can be used in numerous space and commercial refrigeration applications, including food refrigerator/freezers, laboratory freezers, and freeze dryers. Pulse-tube Refrigerators can also be used to cool detectors and electronic...

Briefs : Motion Control
Device for High-Pressure Fused Deposition of Engineering Polymers From Feed Rods

A more versatile delivery system for fused deposition has recently been developed. This system uses a very stiff, precise, and compact actuator to drive a small piston/cylinder extruder that has a heated nozzle. Because feed rods are used as the feed material, this...

Briefs : Materials
Reducing CTE Mismatch Between Coatings and Si-Based Ceramics

Two techniques have been proposed to reduce thermal-expansion mismatches between (a) substrates made of silicon, silicon-based ceramics, and silicon-based-ceramic composite materials and (b) surface coats that protect the substrates against chemical attack in oxidizing and/or...

Briefs : Electronics & Computers
Hardware-Command-Decoding ASIC

A hardware-command-decoding application-specific integrated circuit (HCD ASIC) is designed to decode digital command signals transmitted from a ground station to a spacecraft (uplink commands). Implemented in the ASIC is a portion of the spacecraft uplinkprotocol specified in the widely used Consultative Committee...

Briefs : Motion Control
Earthwormlike Exploratory Robots

Mobile robots that would resemble earthworms have been proposed for use in exploring remote, hostile, or inaccessible terrain surface and subsurface environments. This class of robots would be a special case of a more general class of proposed small, lightweight, relatively inexpensive exploratory robots....

Briefs : Electronics & Computers
Instrument Records Electric Fields Generated by Lightning

A portable, self-contained, compact instrument measures and records transient electric fields generated by nearby lightning strikes. This instrument complements, and in many respects is similar to, the one described in "Instrument Records Magnetic Fields Generated by Lightning"...

Briefs : Photonics/Optics
Micromachined Interferometric Optoelectronic Display Devices

Devices containing planar arrays of micromachined, electrostatically adjustable Fabry-Perot interferometers are undergoing development. These devices could be designed, for example, as color high-definition television displays, as larger flat-panel displays for indoor and outdoor...

Briefs : Electronics & Computers
Column-Loading Input Chip for Neural-Network Module

The column-loading input chip (CLIC) is a conceptual integrated-circuit chip that would serve as an interface between (1) any of various sources of image data and (2) a three-dimensional analog neural network (3DANN) of the type described in "Neural-Network Modules for High-Speed Image...

Briefs : Electronics & Computers
DC-Excited Thermostrain-Gauge Signal-Conditioning Circuit

The figure illustrates a dc-excited Anderson-loop circuit that includes (1) thermocouples for measuring the temperature of the strain gauge and (2) a signal-conditioning circuit that separates the temperature and strain-gauge signals in the sense that one output voltage is proportional...

Briefs : Software
Application Specific Integrated Circuit Physical Layout for the RSDL ASIC

An integrated circuit physical layout has been developed for the RSDL ASIC™ — an integrated circuit that encodes telemetry data and transfers the data (which are grouped together in transfer frames) to a radio transmitter. The RSDL ASIC is described in "ASIC for...

Briefs : Materials
Single Crystal Nickel-Base Superalloy

A modified alloy, known as Modified PWA1484, is a single-crystal nickel-base superalloy, developed under a NASA Marshall Space Flight Center contract for use as a turbine blade and vane alloy for the space-shuttle main engine(SSME). This alloy is a modified PWA 1484 composition that uses innovative...

Briefs : Physical Sciences
Software Models Processes in a Gaseous Chemical Reactor

The Simple Analysis of Materials Processing Reactors (SAMPR) computer code is meant for the analysis of plasma and nonplasma processes used in manufacturing semiconductors. The code can also be used to analyze any chemical-processing reactor with gaseous (but not liquid) streams.

Briefs : Photonics/Optics
Active Fiber Optic Microelectromechanical Systems Aligner

As currently practiced, packaging of individual optoelectronic components accounts for 40-50 percent of product cost. The development of higher-volume, lower-cost optoelectronic manufacturing technologies must take place in order to accelerate the installation of optoelectronics in...

Briefs : Electronics & Computers
Estimating Attitude From GPS Measurements on One Antenna

A technique for estimating the boresight direction of a Global Positioning System (GPS) receiver antenna involves utilization of the relationship between the strengths of received signals and the direction-dependent antenna gain pattern. The technique is fundamentally different from, and...

Briefs : Physical Sciences
Automated Calibration of Temperature Transducers

An automated system of laboratory equipment and computer hardware and software reduces the time that technicians must spend in calibrating temperature transducers. The laboratory equipment includes a controlled-temperature bath, two digital multimeters for processing the outputs of two...

Briefs : Electronics & Computers
Lightweight, Radiation-Resistant EMI Shields

Due to their low density and exceptionally high strength and modulus, graphite fiber composites are being used increasingly for the fabrication of aircraft and spacecraft. Because of their superior mechanical properties, these composites have been replacing metals, such as aluminum alloys, in many...

Briefs : Motion Control
Miniature Multispeed Transmissions for Small Motors

A design has been developed for manufacturing multispeed transmissions that are small enough to be used with minimotors - electromagnetic motors with power ratings of less than 1 W. Like similar, larger systems, such as those in automobiles, the proposed mechanism could be used to satisfy a...

Briefs : Photonics/Optics
Enhancements to Fiber Optic Bragg Grating Sensors and Demodulation Systems

The Boeing Company has developed and patented certain enhancements to commercially available Bragg grating sensors and demodulation systems. These patents (Nos. 4,471,659, 4,668,093, 5,380,995, 5,563,967, and 5,627,927) are available for license. Knowhow related to these...

Briefs : Manufacturing & Prototyping
Apparatus for Coating and Cold Welding in Vacuum

The figure illustrates selected aspects of a manually actuated apparatus for use in coating two small objects with suitable metals, then forcing the two objects together at the coated flat surfaces with uniform pressure to cold-weld them to each other. The design of this apparatus provides for...

Briefs : Mechanical & Fluid Systems
Automated PreLaunch Loads Estimation (APLLE)

Over the past year, the Structural Dynamics and Loads Branch of Marshall Space Flight Center has been calculating prelaunch ground winds for several different launch-vehicle configurations. Engineers developed a computer programming system to streamline the analysis cycle.

Briefs : Photonics/Optics
Variable-Wavelength Micromachined Fabry-Perot Interferometers

The figure schematically shows a micromachined Fabry-Perot interferometer that, when fully developed, would be part of a two-dimensional array of such interferometers in a flat-panel display device. The interferometers, arrays, and display devices according to this concept would be...

Briefs : Information Technology
Automated System for Acting on Findings From Inspections

The Automated Nonconformance System, based at Stennis Space Center, is a computer network dedicated to administration of inspections and repairs of rocket engines. This automated system was developed to replace a manual system in which paper documents were used to document the steps of...

Briefs : Photonics/Optics
Room-Temperature External-Cavity Diode Lasers at 2.0 µm

External-cavity diode lasers (ECDLs) have been commercially available for several years. Since their introduction, they have found applications ranging from telecommunications to atomic spectroscopy. These lasers provide a combination of extremely narrow linewidth, broad tunability, and...

Briefs : Electronics & Computers
Performance of a Soft Digital-Data-Transition Tracking Loop

A report discusses the performance of a soft digital-data-transition tracking loop (DTTL) in a radio receiver that recovers digital data conveyed by binary phase-shift keying. The DTTL is used as a symbol synchronizer; it provides symbol timing to essential parts of the receiver. The...

Briefs : Motion Control
Navigation and Control of Continuous Mining Systems

Research conducted at the Pittsburgh Research Center (formerly U.S. Bureau of Mines) developed technology that will allow computer-assisted operation of mechanized equipment normally used in underground room-and-pillar coal mining, while permitting workers to be located away from the hazardous...

Briefs : Physical Sciences
Solar/Infrared Aerobots for Exploring Several Planets

A report discusses a class of balloon-borne robotic instrumentation systems that have been proposed for use in exploring Venus, Jupiter, Saturn, Uranus, and Neptune. The balloons would be of the Montgolfier type; that is, buoyancy would be achieved through heating of atmospheric gases...

Briefs : Electronics & Computers
Computer System for Managing Construction Projects

An automated system of computer hardware and software has been developed for managing construction projects at Stennis Space Center. This system replaces an older collection of paper-based subsystems, wherein documents were copied, filed, and distributed in labor-intensive processes. Data...

Briefs : Motion Control
Hydraulically Driven High-Speed Spindle for General Machining

A hydraulically driven high-speed spindle system for milling, machining, facing, drilling, and joining metallic and nonmetallic materials has been developed. Spindles are the most critical elements of high-speed milling machines. The keys to successful design of high-speed spindles...

Briefs : Physical Sciences
Analysis of Stresses and Deflections in RTDs

A report presents an analysis of stresses and deflections in resistance temperature detectors (RTDs) of various model numbers with standard sizes and shapes. The RTDs are assumed to be installed in pipes that contain flows of oxygen and hydrogen in a test facility at Stennis Space Center. The...

Briefs : Information Technology
Computer Network for Management of Inspection Data

The Nondestructive Inspection and Evaluation Management System (NIMS), based at Stennis Space Center, is a computer network dedicated to administration of a large data base pertaining to nondestructive inspections of rocket-engine components. The NIMS serves as both an electronic archive of...

Briefs : Robotics, Automation & Control
Improved Hybrid System Protects Airfoils Against Icing

An improved hybrid thermal/mechanical system has been developed to protect airplane wings and other airfoils against the accretion of ice, which degrades aerodynamic performance. The system is designed with particular attention to advanced, high-performance airfoils, which exhibit...

Briefs : Mechanical & Fluid Systems
The Modified Fully Utilized Design Method

The modified fully utilized design (MFUD) method is undergoing development for use by engineers who favor traditional methods of designing structures over methods based on advanced calculus and nonlinear mathematical programming techniques. Thus far, the MFUD has been developed for trusses, with...

Briefs : Motion Control
A Technique For Compensating Joint Limits in a Robot Manipulator

A robust, optimal, adaptive technique for compensating rate and position limits in the joints of a six-degree-of-freedom manipulator has been developed. In this new algorithm, the unmet demand as a result of actuator saturation is redistributed among the remaining unsaturated...

Briefs : Physical Sciences
Carbon/Carbon Shield/Antenna Structure

A proposed lightweight, off-axis reflector structure for a microwave communication antenna would be made of a carbon/carbon composite material. The structure was conceived for use aboard the Solar Probe spacecraft, where it would also serve as a shield to protect the spacecraft against solar radiation at...

Briefs : Electronics & Computers
ASIC Physical Layout for the HCD ASIC

An integrated circuit (IC) physical layout has been developed for the HCD ASIC - an application-specific integrated circuit that decodes digital command signals transmitted from a ground station to a spacecraft (uplink commands). The HCD ASIC is described in "Hardware-Command-Decoding ASIC" (NPO-19615),...

Briefs : Electronics & Computers
ASIC for Reed-Solomon Coding and Related Functions

The Reed-Solomon downlink application-specific integrated circuit (RSDL ASIC) performs Reed-Solomon encoding of telemetry data, internally generates all timing and control signals necessary for the RS encoder, transfers frames of encoded data to a radio transmitter, and performs ancillary...

Briefs : Photonics/Optics
Making Single-Crystal Fibers in a Laser-Heated Floating Zone

Figure 1 shows an apparatus for growing a single-crystal fiber by solidification from a floating zone of laser-heated molten material on the tip of a feed rod. The apparatus can be used to produce single-crystal fibers of various highly pure ceramic and metal compositions, controlled...

Briefs : Robotics, Automation & Control
Evaluation of a "Smart" Aircraft Control Actuator

An aircraft control actuator that incorporates self-contained control electronics has been installed in the F-18 Systems Research Aircraft and evaluated in flight tests. This "smart" actuator is a prototype of fly-by-wire servoactuators for future advanced aircraft.

Briefs : Electronics & Computers
Micromachined Tunneling Accelerometer for Use in Outer Space

Two short reports describe a micromachined quantum-mechanical-tunneling accelerometer and radiation-hardened support electronics designed for use in outer space. Like the micromachined tunneling accelerometers described previously in NASA Tech Briefs, this device is based on the use...

Briefs : Materials
Muscle Wires for Planetary-Exploration Robots

A report proposes the use of muscle wires as mechanical actuators for planetary-exploration robots. Muscle wires are commercially available in kit form in the hobby market, and have been described (though not explicitly called "muscle wires") in previous articles in NASA Tech Briefs. A muscle wire...

Briefs : Information Technology
Wavelet Processing for Aeroservoelastic-Stability Analysis

A wavelet-based modal-parameter-extraction procedure has been developed to augment wavelet filtering and thereby produce more-realistic, robust aeroservoelastic-stability margins. The procedure is intended for use in processing data from aircraft flight tests.

Briefs : Motion Control
Hybrid Propulsion System for Returning a Sample From Mars

A paper suggests the development of a hybrid rocket engine and associated equipment for returning a sample of material from Mars at relatively low cost. In a hybrid rocket engine, a solid fuel is burned by use of a liquid or gaseous oxidizer, the flow of which can be throttled to control...

Briefs : Electronics & Computers
Optoelectronic System Measures Tile Cavities

A hand-held optoelectronic shop tool measures cavities of the order of 6 in. (15 cm) in length and width, 2 to 4 in. (5 to 10 cm) in depth, with nominally flat side walls, and either curved or flat outer and inner surfaces. The system is called the Tile Cavity Measurement System (TCMS) because in the...