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Lightweight, High-Strength Nanocomposite Magnesium for Radiators

New material offers an exceptional balance of properties and cost. Marshall Space Flight Center, Alabama The next generation of radiators will be designed using a composite with the combination of the lowest density, highest thermal conductivity, and highest strength. A scalable, low-cost process was developed to advance state-of-the-art metal matrix thermal conductors to reach a theoretical goal of 578 W/mK (270W/mK achieved), a density less than aluminum (1.7g.cc achieved), and a yield strength over 30 ksi (≈207 MPa, 42 ksi achieved). The incorporation of nanofibers into metals has been heavily researched to improve mechanical and thermal properties of materials, with limited technical and commercial success. The problem of incorporating high-aspect-ratio, high-surface-area particles (including fiber and flake) with controlled and repeatable concentration and distribution into molten metals is a large undertaking, and must factor in the molten metal temperature, composition, and surface tension. Direct feeding of the particles does not work, as particles burn, react with the molten metal, or do not stay in the metal. Other feeding mechanisms such as auger feeding into the metal, in-situ formation, and stir casting are cost-prohibitive and not always scalable.

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Advanced Protective Coatings for Graphite Substrates

This innovation enables application of graphite components in a hydrogen environment at very high temperatures. John H. Glenn Research Center, Cleveland, Ohio The purpose of this innovation is to develop advanced multilayered coating architectures to protect graphite substrates from hot hydrogen attack. The concept consists of coating the graphite substrate with metallic and non-metallic layers consisting of ZrC; Nb, Mo, and/or Nb-Mo alloy; and/or Mo2C.

Posted in: Briefs, TSP

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Plasma Extraction of Oxygen from the Martian Atmosphere

Microwave plasmas use systems that are smaller, lighter, and less complex than traditional reactors. Marshall Space Flight Center, Alabama Extraction of oxygen from the abundant carbon dioxide present on Mars (96% atmospheric composition) is an important objective in preparation for missions to the planet. Oxygen is not only a fundamental reactant with high-specific-energy chemical fuels such as hydrogen and methane, but, along with water, it is arguably one of the most critical resources for life support. Using microwave plasma techniques to decompose CO2 into CO and O2, coupled with a technology to separate O2 as it is produced, a robotic processor located on the Martian surface would allow oxygen to be stockpiled for later use. Using innovative standing-wave microwave plasma reactor designs, ubiquitous 2.45-GHz microwave technology was employed to demonstrate 86% single-pass carbon dioxide decomposition.

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Application of Carbon Nanotube Hold-Off Voltage for Determining Gas Composition

Ames Research Center, Moffett Field, California In this innovation, a method and associated system have been created to vary a voltage applied to an exposed end of a carbon nanotube for a selected time interval to promote gas discharge, and to estimate a gas component involved in the discharge. Each component of a gas has a first, lower threshold discharge (voltage value, V∞) at which discharge can occur after a long time delay (t(V∞:ho)≈∞), where “ho” refers to a discharge voltage holdoff value. Application of a voltage V above this lower limit V∞ will cause the gas component to undergo a discharge after a discharge holdoff time t(V:ho) that decreases as V increases above V∞.

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DC Transformer

This transformer can fill a role in which DC conversion potential, coupled with power filtering/storage capability, is required in high-DC power transmission. John F. Kennedy Space Center, Florida A component-level DC transformer was developed in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both DC devices, such that the output voltage of a DC power supply can be stepped up (or down) with a corresponding step down (or up) in current. The DC transformer should be scalable to low-megawatt levels, but is more suited to high-current than high-voltage applications.

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Wallops Flight Facility 6U Advanced CubeSat Ejector (ACE)

Goddard Space Flight Center, Greenbelt, Maryland Six-unit (6U) CubeSats are recognized as the next nanosatellite to be considered for standardization. The CubeSat standard established by California Polytechnic University (Cal Poly), which applies to 1U–3U sizes, has proven to be a valuable asset to the community. It has both provided design guidelines to CubeSat developers and a consistent, low-risk interface to launch service providers. This has ultimately led to more flight opportunities for CubeSats. A similar path is desired for the 6U CubeSat. Through this process of standardization, a consistent, low-risk interface for the 6U needs to be established.

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Improved Attachment Design for Ceramic Turbine Blades Via Hybrid Concepts

This approach facilitates increased precision and ease of handling the blades during assembly. John H. Glenn Research Center, Cleveland, Ohio This innovation is a hybrid metal-ceramic matrix composite (CMC) turbine blade in which a SiC/SiC CMC airfoil section is bonded to a single-crystal superalloy root section in order to mitigate risks associated with an all-CMC blade inserted in a superalloy disk. This will allow current blade attachment technology (SX blade with a dovetail attachment to a slotted Ni disk) to be used with a ceramic airfoil. The bond between the CMC and single crystal will be primarily mechanical in nature, and enhance with clamping arising from thermal expansion mismatch. Two single-crystal root sections will be bonded to each other using diffusion bonding at temperatures near 1,200 °C. The single crystals will form a clamshell around the CMC, with little or no gap between the metal and ceramic. Upon cooling, the metal will shrink around the CMC to firmly clamp it. It is envisioned that this will allow the blade root to operate at temperatures up to about 800 °C. Single crystals will resist stress relaxation at this temperature, thus maintaining clamping loads for long lives. The hybrid concept plus the method of manufacture is new technology.

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