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White, Electrically Dissipative Thermal Control Coating

Goddard Space Flight Center, Greenbelt, Maryland A highly reflective, white conductive coating system was developed using various layered coatings to maximize the structural, electrical, and optical reflectance properties for spacecraft radiators. The top layer of the system contains a highly reflective white pigment within a dissipative inorganic binder. This layer is above a highly conductive second layer containing a white conductive pigment within the same binder system.

Posted in: Briefs, TSP

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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: 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: 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.

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Toughened Uni-piece Fibrous Reinforced Oxidation-Resistant Composite (TUFROC)

Ames Research Center, Moffett Field, California TUFROC has an exposed surface edge design and an appropriate materials combination for a space vehicle that will survive the mechanical stresses induced in the initial ascent, and will subsequently survive the extreme heating and mechanically stressful environment of re-entry. It provides a thermal protection tile attachment system, suitable for application to a space vehicle leading edge, and for other uses in extreme heating environments [up to 3,600 °F (1,982 °C), and possibly higher, for short time intervals].

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High-Efficiency Tantalum-Based Ceramic Composite Structures

Ames Research Center, Moffett Field, California High-efficiency tantalum-based ceramic (HETC) composite structures are suitable for use in thermal protection systems. These composite structures have high-efficiency surfaces (low catalytic efficiency and high-emittance), thereby reducing heat flux to a spacecraft during planetary reentry. These low catalytic efficiency and high-emittance ceramic materials were developed in order to increase the capability of a Toughened Uni-Piece Fibrous Insulation (TUFI)-like thermal protection system, with its high-impact resistance, to temperatures above 3,000 °F (≈1,650 °C). These ceramics have been applied to various aerodynamic configurations, such as wedge, wing-leading segment, and conventional tile shapes used on high-speed atmospheric entry vehicles. In addition, this family of tantalum-based ceramics exhibits low catalytic efficiency to atom recombination during exposure to highenergy dissociated hypersonic flow.

Posted in: Briefs

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Use of Solvent-Free Conditions/Dry Mixing for Functionalizing Carbon Nanotubes

Lyndon B. Johnson Space Center, Houston, Texas Two methods have been developed for functionalizing carbon nanotubes in solvent-free conditions. In one method, purified single-walled carbon nanotubes (SWNTs) and a diazonium salt are added to a metal vial, which is loaded with a stainless steel ball bearing. The metal vial is clamped into a mill mixer, and is mixed for one hour. The unreacted diazonium salt is then dissolved in a volume of acetonitrile that efficiently solubilizes the salt to remove the unreacted functionalization reagent. The functionalized nanotubes are then collected by filtration.

Posted in: Briefs

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