Special Coverage

Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines

Coated Glass for Transparent Heating Elements

This coated glass can be used in high-humidity and high-altitude applications such as architectural and aircraft windows.

Applying an electric current to specially coated glass results in radiant heat energy. This process creates a transparent heating element with near- uniform surface temperatures. Manufacturing the heating element requires an ordinary pane of float glass. A fluorine-doped tin oxide coating (SnO2:F) measuring 0.25 micron thick is applied to one surface of the glass during fabrication. The coating conducts electricity, has a very tightly controlled resistance, has no appreciable color or structure, and is quite transparent. The coating has low emissivity properties that help contribute to the efficiency of the heated glass.

Posted in: Briefs, Materials, Heat transfer, Heat transfer, Fabrication, Coatings Colorants and Finishes, Coatings, colorants, and finishes, Conductivity, Glass

Deep-Sea Hydrothermal-Vent Sampler

This apparatus collects hydrothermal-plume samples uncontaminated by surrounding water.

An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300°C), deep-sea hydrothermal- vent samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Water, Bacteria, Test equipment and instrumentation, Marine vehicles and equipment

Mars Rocket Propulsion System

A report discusses the methane and carbon monoxide/LOX (McLOx) rocket for ascent from Mars as well as other critical space propulsion tasks. The system offers a specific impulse over 370 s — roughly 50 s higher than existing space-storable bio- propellants. Current Mars in-situ propellant production (ISPP) technologies produce impure methane and carbon monoxide in various combinations. While separation and purification of methane fuel is possible, it adds complexity to the propellant production process and discards an otherwise useful fuel product. The McLOx makes such complex and wasteful processes unnecessary by burning the methane/CO mixtures produced by the Mars ISPP systems without the need for further refinement.

Posted in: Briefs, Mechanical Components, Mechanics, Carbon dioxide, Methane, Propellants, Spacecraft fuel, Rocket engines

Two-Stage Passive Vibration Isolator

The design and testing of a structural system were implemented to hold the optics of the planned Space Interferometry Mission (SIM) at positions and orientations characterized by vibrational translation and rotation errors of no more than a few nanometers or a few milliarcseconds, respectively. Much of the effort was devoted to a test bed for verifying the predicted behavior of a vibration-isolation structural subsystem working together with an active control system for positioning and orienting the SIM optics.

Posted in: Briefs, Mechanical Components, Mechanics, Calibration, Optics, Optics, Vibration, Vibration, Mountings, Spacecraft

Altimetry Using GPS-Reflection/Occultation Interferometry

A Global Positioning System (GPS)- reflection/occultation interferometry was examined as a means of altimetry of water and ice surfaces in polar regions. In GPS- reflection/occultation interferometry, a GPS receiver aboard a satellite in a low orbit around the Earth is used to determine the temporally varying carrier-phase delay between (1) one component of a signal from a GPS transmitter propagating directly through the atmosphere just as the GPS transmitter falls below the horizon and (2) another component of the same signal, propagating along a slightly different path, reflected at glancing incidence upon the water or ice surface.

Posted in: Briefs, Physical Sciences, Altimeters, Global positioning systems, Global positioning systems (GPS), Altimeters, Global positioning systems, Global positioning systems (GPS), Weather and climate, Satellites

Improved Thermal Design of a Compression Mold

A compression tool used to make 1-in. (2.5-cm) diameter disks of high-temperature polymers was designed to be shorter and of larger diameter than conventional tools to reduce heat loss to the surrounding air, thus making more efficient use of applied heat. This system is less sensitive to the amount and quality of insulation than previous tools, provides more repeatable processing, and improves the quality of the samples produced. These improvements come without increasing the weight of the punch portion of the tool over that of a conventional version, an important quality when handling lower-viscosity resins.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Manufacturing equipment and machinery, Molding, Resins, Reliability, Reliability

Enhanced Pseudo-Waypoint Guidance for Spacecraft Maneuvers

An enhanced version of the scheme reported in “Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers” (NPO-42753), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 73 was developed. To recapitulate: the scheme provides algorithms for guidance and control (G&C) of a spacecraft maneuvering near a small astronomical body. The open-loop guidance problem is solved in advance or in real time by use of the pseudo-waypoint generation (PWG) method. Feedback control is implemented to track PWG trajectories, in a manner that enables updating of G&C in a model-predictive manner. The scheme includes silent periods following each thruster firing.

Posted in: Briefs, Mechanical Components, Mechanics, Mathematical models, Spacecraft guidance, Spacecraft guidance, Booster rocket engines

Thermally Driven Josephson Effect

A concept is proposed of the thermally driven Josephson effect in superfluid helium. Heretofore, the Josephson effect in a superfluid has been recognized as an oscillatory flow that arises in response to a steady pressure difference between two superfluid reservoirs separated by an array of submicron-sized orifices, which act in unison as a single Josephson junction. Analogously, the thermally driven Josephson effect is an oscillatory flow that arises in response to a steady temperature difference.

Posted in: Briefs, Physical Sciences, Computational fluid dynamics, Thermodynamics, Thermodynamics, Gases

Determining Concentration of Nanoparticles From Ellipsometry

Counting of particles is not necessary.

A method of using ellipsometry or polarization analysis of light in total internal reflection of a surface to determine the number density of gold nanoparticles on a smooth substrate has been developed. The method can be modified to enable determination of densities of sparse distributions of nanoparticles in general, and is expected to be especially useful for measuring gold-nanoparticle-labeled biomolecules on microarrays.

Posted in: Briefs, Physical Sciences, Nanomaterials

Gold Nanoparticle Labels Amplify Ellipsometric Signals

The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation.

Posted in: Briefs, Physical Sciences, Amplifiers, Amplifiers, Biomaterials, Materials identification

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