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Briefs: Materials
Multi-Shock Blankets for Protecting Spacecraft
A report discusses multi-shock blankets, which are under investigation for use in protecting spacecraft against orbiting debris from prior spacecraft missions. Multi-shock blankets are described in comparison with early protective metallic "bumpers" and with a somewhat more recent invention called the...
Briefs: Mechanical & Fluid Systems
Airlocks for Pressurized Rovers
A report presents a survey of the design engineering and scientific literature on airlocks and on planetary-exploration vehicles ("rovers"), from the perspective of evaluating existing and potential design concepts for airlocks for pressurized rovers. The airlocks are the key to designing a pressurized rover that...
Briefs: Medical
Spacecraft-Facility Microbes Tolerate H2O2, NaCl, and Heat
A report describes experiments that were performed to isolate and characterize microbes that survive conditions of controlled circulation of air, desiccation, low nutrient concentrations, and moderately high temperatures in a spacecraft-assembly facility. These conditions are more severe...
Briefs: Materials
Study of High-Performance Polyimide Foams
This report describes an experimental study of thermal-stability, mechanical, and flammability properties of foams of several different densities made of three different polyimides. The study was performed because (1) prior such studies were performed on polyimide films rather than foams and (2) the...
Briefs: Physical Sciences
Subgrid Analysis of Mixing Layer With Evaporating Droplets
This report presents an analysis of a database from computational simulations of a droplet-laden mixing layer (i.e., evaporating droplets of a liquid fuel in air) undergoing a transition to turbulence. The basic governing equations were those of transport of discrete droplets through a...
Briefs: Physical Sciences
Validated Model of a Fluid Drop for All Pressures
The report "A Validated All-Pressure Fluid Drop Model and Lewis Number Effects for a Binary Mixture" presents one in a series of theoretical and computational studies of the subcritical and subpercritical behaviors of a drop of fluid and, in particular, a drop of heptane surrounded by nitrogen The...
Briefs: Photonics/Optics
A prototype ring laser in which a transparent microsphere serves as an electromagnetic-mode selector has been constructed in a continuing effort to develop optoelectronic oscillators...
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Briefs: Photonics/Optics
A class of proposed photonic switching devices would utilize interactions among light bullets that have been studied theoretically. Because they function at speeds much greater than those of...
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Briefs: Photonics/Optics
The figure depicts an example of a proposed type of optoelectronic oscillator (OEO) based on some of the same principles as those described in the preceding article. In the proposed...
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Briefs: Photonics/Optics
An assembly that includes electromechanical rotary actuators has been developed specifically for use as the shutter mechanism of a cryogenic infrared camera that will be part of an...
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Briefs: Electronics & Computers
Optoelectronic oscillators (OEOs) of a proposed type would be based partly on the use of fiber-optic linear or ring resonators in place of the long fiber-optic delay lines that have...
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Briefs: Mechanical & Fluid Systems
Variable-Specific-Impulse Magnetoplasma Rocket
Johnson Space Center has been leading the development of a high-power, electrothermal plasma rocket — the variable- specific-impulse magnetoplasma rocket (VASIMR) — that is capable of exhaust modulation at constant power. An electrodeless design enables the rocket to operate at power densities much...
Briefs: Electronics & Computers
The "smart" current-signature sensor is an instrument that noninvasively measures and analyzes steady-state and transient components of the magnetic field of (and, thus, indirectly, the...
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Briefs: Electronics & Computers
An improved design for baseplates in silicon microsensors reduces parasitic capacitances between adjacent coplanar electrodes. It also reduces thermal-expansion mismatches, which are...
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Briefs: Mechanical & Fluid Systems
A proposal has been made to develop bimorph actuators and force sensors based on carbon nanotubes. The proposed devices could make it possible to generate, sense, and control displacements and...
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Briefs: Physical Sciences
"Health check" would be built into pressure transducers, according to a proposal, to enable occasional, rapid, in situ testing of the transducers between normal pressure-measurement operations....
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Briefs: Electronics & Computers
Improvements in a Fast Transient-Voltage Recorder
Some improvements have been made in an instrument designed expressly for recording lightning-induced transient voltages on power and signal cables. The instrument as it existed prior to the improvements was described in "Fast Transient-Voltage Recorder" (KSC-11991), NASA Tech Briefs, Vol. 23, No....
Briefs: Electronics & Computers
Microscopic cathodes based on field emission (in contradistinction to thermionic emission) are undergoing development with a view toward using them as miniature or scalable sources of electrons in diverse...
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Briefs: Software
LabVIEW as Flight Software With VxWorks Operating System
A development effort under way at the time of reporting the information for this article is directed toward producing a version of the LabVIEW data-acquisition software that would be suitable for use as flight software that could be executed in the VxWorks real-time operating system. The...
Briefs: Mechanical & Fluid Systems
Robot for Positioning Sensors in a Plant-Growth Chamber
The Advanced Life Support Automated Remote Manipulator (ALSARM) is a three-degree-of-freedom robotic system that positions an array of sensors inside a closed-system hydroponic chamber used in research on the production of biomass and the use of hydroponic subsystems of life-support...
Briefs: Software
MPP Port of PVM to a Beowulf Computer System
The latest version of the Parallel Virtual Machine (PVM) computer program, denoted PVM 3.4.3, incorporates a massively-parallel-processor (MPP) software port that enables a user working on a computer outside a Beowulf system (a cluster of personal computers that run the Linux operating system) to...
Briefs: Software
Software for Iterative Optimization of Plans
The Iterative Plan Optimization computer program automatically optimizes plans with respect to preferences expressed by human planners. This program incorporates a generalization of commonly occurring plan-quality metrics to provide a language for expression of preferences. The program implements a...
Briefs: Software
Software for Planning an SAR Antarctic Mapping Mission
The AMM Automated Mission Planner computer program was developed to save time and money by automating much of the planning of the Second RADARSAT Antarctic Mapping Mission (AMM), which was scheduled to take place at the time of writing this article. The planning problem for this and other...
Briefs: Materials
A methodology for predicting stresses and the resultant cracking in plasma-sprayed thermal-barrier coatings (TBCs) has been developed. The methodology is built around a computer code that...
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Briefs: Motion Control
Self-tuning impact dampers have been proposed as improved means for suppressing vibrations in the rotor blades of turbomachines (turbines and compressors). Dampers are needed because...
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Briefs: Motion Control
A double-parallelogram ("porch swing") carriage mechanism has been devised to provide for free linear motion of one or more retroreflector(s) in a Fourier-transform infrared spectrometer....
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Briefs: Motion Control
Measurement and control systems based on microwave radiometers would be used to prevent unstarts in the next generation of high-speed (up to mach 2.4) civil-transport airplanes, according to a...
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Briefs: Motion Control
Non-Ablative Aeroshells
Two reports propose the development of non-ablative aeroshells for braking of spacecraft entering the atmospheres of Earth, Mars, and other planets. The primary advantages of non-ablative aeroshells, relative to ablative aeroshells, results from reduced mass and increased aerodynamic stability of the aeroshell occasioned by...
Briefs: Electronics & Computers
The NASA Spacecraft Transponding Modem
A report describes the NASA Spacecraft Transponding Modem (STM) — a spacecraft transponder now under development for planned use on deep-space missions scheduled for launch in the year 2003. In comparison with a traditional deep-space transponder, the STM will be smaller and less power hungry; the reductions...

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