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Ultra-High-Temperature Ceramic Composites with SiC Reinforcements

Potential applications are at temperatures approaching 4,000 °F (≈2,200 °C). Ames Research Center, Moffett Field, California Future-generation materials for use on space transportation vehicles require substantial improvements in material properties, leading to increased reliability and safety, as well as intelligent design to allow for current materials to meet future needs. Ultra-high-temperature ceramics (UHTCs) composed primarily of metal diborides are candidate materials for sharp leading edges on hypersonic re-entry vehicles. The mechanical performance of ceramics in general would benefit from a high-aspect reinforcement phase.

Posted in: Materials, Briefs

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Cathode Discharge Catalytic Systems for Hydrogen Recovery from Methane

Methane previously vented into space is now used for hydrogen recovery. Marshall Space Flight Center, Alabama In the process of recovery and regeneration of cabin atmosphere to supply oxygen to facilitate extended-duration manned missions, including expeditions to Mars or a return to the Moon, one of the byproducts of this reaction is waste methane, which is vented into space. This innovation reclaims hydrogen from the methane using a low-power, non-thermal plasma discharge process based on distributed hollow-cathode and filamentary discharges. This hollow-cathode, non-thermal plasma (HCNTP) is characterized by electrons and heavy particles being in thermodynamic non-equilibrium with electrons heated to 10,000 K and above, while ions and neutral species remain at near ambient temperature. By using pulsed voltage waveforms for generating the plasma discharge, a majority of electric energy goes into heating electrons.

Posted in: Materials, Briefs

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Beneficiation of Planetary Regolith by Pneumatically Enhanced Tribocharging of Granular Material

This technique has applications in all types of material handling, mining, and processing. John F. Kennedy Space Center, Florida Liberation of oxygen from the mineral ilmenite (FeTiO3), which may be found on the Moon, Mars, or asteroids, is inefficient due to the abundance of other minerals in the excavated regolith that are present but not needed during the chemical processing. Energy for the reduction reaction is in short supply on the lunar, Martian, and asteroid surfaces. The ilmenite should be separated from other minerals to simplify and improve the process efficiency. Lunar and planetary basaltic lavas contain ilmenite, but they consist only of 12 to 20 percent by weight.

Posted in: Materials, Briefs

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Robotic Fabric Moves and Contracts

Researchers are developing a robotic, sensor-embedded fabric that moves and contracts. Such an elastic technology could enable a new class of soft robots, stretchable garments, "g-suits" for pilots or astronauts to counteract acceleration effects, and lightweight, versatile robots to roam alien landscapes during space missions.The robotic fabric is a cotton material containing sensors made of a flexible polymer and threadlike strands of a shape-memory alloy. The strands return to a coiled shape when heated, causing the fabric to move."We have integrated both actuation and sensing, whereas most robotic fabrics currently in development feature only sensing or other electronic components that utilize conductive thread," said Rebecca Kramer, an assistant professor of mechanical engineering at Purdue University. "We also use standard sewing techniques to introduce the thread-like actuators and sensors into the fabric, so they could conceivably be integrated into the existing textile manufacturing infrastructure."SourceAlso: See other Sensors tech briefs.

Posted in: Materials, Plastics, Motion Control, Sensors, Aerospace, Machinery & Automation, Robotics, News

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3D Printer Heads to International Space Station

The first 3D printer is soon to fly into Earth orbit, finding a home aboard the International Space Station (ISS). The size of a small microwave, the unit is called Portal. The hardware serves as a testbed for evaluating how well 3D printing and the microgravity of space combine. The soon-to-fly 3D printer can churn out plastic objects within a span of 15 minutes to an hour.The technology works by extruding heated plastic, and then builds successive layers to make a three-dimensional object. In essence, the test on the ISS might well lead to establishing a “machine shop” in space. The 3D printer experiment is being done under the tech directorate's Game Changing Development Program, a NASA thrust that seeks to identify and rapidly mature innovative/high impact capabilities and technologies for infusion in a broad array of future NASA missions.According to the team, manufacturing assets in space, as opposed to launching them from Earth, will accelerate and broaden space development while providing unprecedented access for people on Earth to use in-space capabilities. SourceAlso: Learn about Ammonia Leak Detection on the ISS.

Posted in: Manufacturing & Prototyping, Rapid Prototyping & Tooling, Materials, Plastics, Test & Measurement, Aerospace, News

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Researchers Equip Robot with Novel Tactile Sensor

Researchers at MIT and Northeastern University have equipped a robot with a novel tactile sensor that lets it grasp a USB cable draped freely over a hook and insert it into a USB port.The sensor is an adaptation of a technology called GelSight, which was developed by the lab of Edward Adelson, the John and Dorothy Wilson Professor of Vision Science at MIT, and first described in 2009. The new sensor isn’t as sensitive as the original GelSight sensor, which could resolve details on the micrometer scale. But it’s smaller — small enough to fit on a robot’s gripper — and its processing algorithm is faster, so it can give the robot feedback in real time.A GelSight sensor — both the original and the new, robot-mounted version — consists of a slab of transparent, synthetic rubber coated on one side with a metallic paint. The rubber conforms to any object it’s pressed against, and the metallic paint evens out the light-reflective properties of diverse materials, making it much easier to make precise optical measurements.In the new device, the gel is mounted in a cubic plastic housing, with just the paint-covered face exposed. The four walls of the cube adjacent to the sensor face are translucent, and each conducts a different color of light — red, green, blue, or white — emitted by light-emitting diodes at the opposite end of the cube. When the gel is deformed, light bounces off of the metallic paint and is captured by a camera mounted on the same cube face as the diodes.From the different intensities of the different-colored light, the algorithms developed by Adelson’s team can infer the three-dimensional structure of ridges or depressions of the surface against which the sensor is pressed. Source Read other Sensors tech briefs.

Posted in: Photonics, Optics, Materials, Motion Control, Sensors, Lighting, LEDs, Machinery & Automation, Robotics, News

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Researchers Control Surface Tension of Liquid Metals

Researchers from North Carolina State University have developed a technique for controlling the surface tension of liquid metals by applying very low voltages, opening the door to a new generation of reconfigurable electronic circuits, antennas and other technologies. The technique hinges on the fact that the oxide “skin” of the metal – which can be deposited or removed – acts as a surfactant, lowering the surface tension between the metal and the surrounding fluid.The researchers used a liquid metal alloy of gallium and indium. In base, the bare alloy has a remarkably high surface tension of about 500 millinewtons (mN)/meter, which causes the metal to bead up into a spherical blob. “But we discovered that applying a small, positive charge – less than 1 volt – causes an electrochemical reaction that creates an oxide layer on the surface of the metal, dramatically lowering the surface tension from 500 mN/meter to around 2 mN/meter,” says Dr. Michael Dickey, an associate professor of chemical and biomolecular engineering at NC State and senior author of a paper describing the work. “This change allows the liquid metal to spread out like a pancake, due to gravity.”The researchers also showed that the change in surface tension is reversible. If researchers flip the polarity of the charge from positive to negative, the oxide is eliminated and high surface tension is restored.  The surface tension can be tuned between these two extremes by varying the voltage in small steps.SourceAlso: Learn about Gradient Metal Alloys Fabricated Using Additive Manufacturing.

Posted in: Electronics & Computers, Electronics, Power Management, Materials, Metals, RF & Microwave Electronics, Antennas, News

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